diff --git a/src/coins.cpp b/src/coins.cpp
index f5e3b5b17..0e2503b76 100644
--- a/src/coins.cpp
+++ b/src/coins.cpp
@@ -1,376 +1,376 @@
 // Copyright (c) 2012-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include "coins.h"
 
 #include "memusage.h"
 #include "random.h"
 
 #include <cassert>
 
 /**
  * calculate number of bytes for the bitmask, and its number of non-zero bytes
  * each bit in the bitmask represents the availability of one output, but the
  * availabilities of the first two outputs are encoded separately
  */
 void CCoins::CalcMaskSize(unsigned int &nBytes,
                           unsigned int &nNonzeroBytes) const {
     unsigned int nLastUsedByte = 0;
     for (unsigned int b = 0; 2 + b * 8 < vout.size(); b++) {
         bool fZero = true;
         for (unsigned int i = 0; i < 8 && 2 + b * 8 + i < vout.size(); i++) {
             if (!vout[2 + b * 8 + i].IsNull()) {
                 fZero = false;
                 continue;
             }
         }
         if (!fZero) {
             nLastUsedByte = b + 1;
             nNonzeroBytes++;
         }
     }
     nBytes += nLastUsedByte;
 }
 
 bool CCoins::Spend(uint32_t nPos) {
     if (nPos >= vout.size() || vout[nPos].IsNull()) return false;
     vout[nPos].SetNull();
     Cleanup();
     return true;
 }
 
 bool CCoinsView::GetCoins(const uint256 &txid, CCoins &coins) const {
     return false;
 }
 bool CCoinsView::HaveCoins(const uint256 &txid) const {
     return false;
 }
 uint256 CCoinsView::GetBestBlock() const {
     return uint256();
 }
 bool CCoinsView::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) {
     return false;
 }
 CCoinsViewCursor *CCoinsView::Cursor() const {
     return 0;
 }
 
 CCoinsViewBacked::CCoinsViewBacked(CCoinsView *viewIn) : base(viewIn) {}
 bool CCoinsViewBacked::GetCoins(const uint256 &txid, CCoins &coins) const {
     return base->GetCoins(txid, coins);
 }
 bool CCoinsViewBacked::HaveCoins(const uint256 &txid) const {
-    return base->HaveCoins(txid);
+    return base->HaveCoins_DONOTUSE(txid);
 }
 uint256 CCoinsViewBacked::GetBestBlock() const {
     return base->GetBestBlock();
 }
 void CCoinsViewBacked::SetBackend(CCoinsView &viewIn) {
     base = &viewIn;
 }
 bool CCoinsViewBacked::BatchWrite(CCoinsMap &mapCoins,
                                   const uint256 &hashBlock) {
     return base->BatchWrite(mapCoins, hashBlock);
 }
 CCoinsViewCursor *CCoinsViewBacked::Cursor() const {
     return base->Cursor();
 }
 
 SaltedTxidHasher::SaltedTxidHasher()
     : k0(GetRand(std::numeric_limits<uint64_t>::max())),
       k1(GetRand(std::numeric_limits<uint64_t>::max())) {}
 
 CCoinsViewCache::CCoinsViewCache(CCoinsView *baseIn)
     : CCoinsViewBacked(baseIn), hasModifier(false), cachedCoinsUsage(0) {}
 
 CCoinsViewCache::~CCoinsViewCache() {
     assert(!hasModifier);
 }
 
 size_t CCoinsViewCache::DynamicMemoryUsage() const {
     return memusage::DynamicUsage(cacheCoins) + cachedCoinsUsage;
 }
 
 CCoinsMap::const_iterator
 CCoinsViewCache::FetchCoins(const uint256 &txid) const {
     CCoinsMap::iterator it = cacheCoins.find(txid);
     if (it != cacheCoins.end()) {
         return it;
     }
     CCoins tmp;
     if (!base->GetCoins(txid, tmp)) {
         return cacheCoins.end();
     }
     CCoinsMap::iterator ret =
         cacheCoins.insert(std::make_pair(txid, CCoinsCacheEntry())).first;
     tmp.swap(ret->second.coins);
     if (ret->second.coins.IsPruned()) {
         // The parent only has an empty entry for this txid; we can consider our
         // version as fresh.
         ret->second.flags = CCoinsCacheEntry::FRESH;
     }
     cachedCoinsUsage += ret->second.coins.DynamicMemoryUsage();
     return ret;
 }
 
 bool CCoinsViewCache::GetCoins(const uint256 &txid, CCoins &coins) const {
     CCoinsMap::const_iterator it = FetchCoins(txid);
     if (it != cacheCoins.end()) {
         coins = it->second.coins;
         return true;
     }
     return false;
 }
 
 CCoinsModifier CCoinsViewCache::ModifyCoins(const uint256 &txid) {
     assert(!hasModifier);
     std::pair<CCoinsMap::iterator, bool> ret =
         cacheCoins.insert(std::make_pair(txid, CCoinsCacheEntry()));
     size_t cachedCoinUsage = 0;
     if (ret.second) {
         if (!base->GetCoins(txid, ret.first->second.coins)) {
             // The parent view does not have this entry; mark it as fresh.
             ret.first->second.coins.Clear();
             ret.first->second.flags = CCoinsCacheEntry::FRESH;
         } else if (ret.first->second.coins.IsPruned()) {
             // The parent view only has a pruned entry for this; mark it as
             // fresh.
             ret.first->second.flags = CCoinsCacheEntry::FRESH;
         }
     } else {
         cachedCoinUsage = ret.first->second.coins.DynamicMemoryUsage();
     }
     // Assume that whenever ModifyCoins is called, the entry will be modified.
     ret.first->second.flags |= CCoinsCacheEntry::DIRTY;
     return CCoinsModifier(*this, ret.first, cachedCoinUsage);
 }
 
 /**
  * ModifyNewCoins allows for faster coin modification when creating the new
  * outputs from a transaction. It assumes that BIP 30 (no duplicate txids)
  * applies and has already been tested for (or the test is not required due to
  * BIP 34, height in coinbase). If we can assume BIP 30 then we know that any
  * non-coinbase transaction we are adding to the UTXO must not already exist in
  * the utxo unless it is fully spent. Thus we can check only if it exists DIRTY
  * at the current level of the cache, in which case it is not safe to mark it
  * FRESH (b/c then its spentness still needs to flushed). If it's not dirty and
  * doesn't exist or is pruned in the current cache, we know it either doesn't
  * exist or is pruned in parent caches, which is the definition of FRESH. The
  * exception to this is the two historical violations of BIP 30 in the chain,
  * both of which were coinbases. We do not mark these fresh so we we can ensure
  * that they will still be properly overwritten when spent.
  */
 CCoinsModifier CCoinsViewCache::ModifyNewCoins(const uint256 &txid,
                                                bool coinbase) {
     assert(!hasModifier);
     std::pair<CCoinsMap::iterator, bool> ret =
         cacheCoins.insert(std::make_pair(txid, CCoinsCacheEntry()));
     if (!coinbase) {
         // New coins must not already exist.
         if (!ret.first->second.coins.IsPruned())
             throw std::logic_error("ModifyNewCoins should not find "
                                    "pre-existing coins on a non-coinbase "
                                    "unless they are pruned!");
 
         if (!(ret.first->second.flags & CCoinsCacheEntry::DIRTY)) {
             // If the coin is known to be pruned (have no unspent outputs) in
             // the current view and the cache entry is not dirty, we know the
             // coin also must be pruned in the parent view as well, so it is
             // safe to mark this fresh.
             ret.first->second.flags |= CCoinsCacheEntry::FRESH;
         }
     }
     ret.first->second.coins.Clear();
     ret.first->second.flags |= CCoinsCacheEntry::DIRTY;
     return CCoinsModifier(*this, ret.first, 0);
 }
 
 const CCoins *CCoinsViewCache::AccessCoins(const uint256 &txid) const {
     CCoinsMap::const_iterator it = FetchCoins(txid);
     if (it == cacheCoins.end()) {
         return nullptr;
     } else {
         return &it->second.coins;
     }
 }
 
 bool CCoinsViewCache::HaveCoins(const uint256 &txid) const {
     CCoinsMap::const_iterator it = FetchCoins(txid);
     // We're using vtx.empty() instead of IsPruned here for performance reasons,
     // as we only care about the case where a transaction was replaced entirely
     // in a reorganization (which wipes vout entirely, as opposed to spending
     // which just cleans individual outputs).
     return (it != cacheCoins.end() && !it->second.coins.vout.empty());
 }
 
-bool CCoinsViewCache::HaveCoinsInCache(const uint256 &txid) const {
-    CCoinsMap::const_iterator it = cacheCoins.find(txid);
-    return it != cacheCoins.end();
+bool CCoinsViewCache::HaveCoinInCache(const COutPoint &outpoint) const {
+    CCoinsMap::const_iterator it = cacheCoins.find(outpoint.hash);
+    return it != cacheCoins.end() && it->second.coins.IsAvailable(outpoint.n);
 }
 
 uint256 CCoinsViewCache::GetBestBlock() const {
     if (hashBlock.IsNull()) hashBlock = base->GetBestBlock();
     return hashBlock;
 }
 
 void CCoinsViewCache::SetBestBlock(const uint256 &hashBlockIn) {
     hashBlock = hashBlockIn;
 }
 
 bool CCoinsViewCache::BatchWrite(CCoinsMap &mapCoins,
                                  const uint256 &hashBlockIn) {
     assert(!hasModifier);
     for (CCoinsMap::iterator it = mapCoins.begin(); it != mapCoins.end();) {
         // Ignore non-dirty entries (optimization).
         if (it->second.flags & CCoinsCacheEntry::DIRTY) {
             CCoinsMap::iterator itUs = cacheCoins.find(it->first);
             if (itUs == cacheCoins.end()) {
                 // The parent cache does not have an entry, while the child does
                 // We can ignore it if it's both FRESH and pruned in the child
                 if (!(it->second.flags & CCoinsCacheEntry::FRESH &&
                       it->second.coins.IsPruned())) {
                     // Otherwise we will need to create it in the parent and
                     // move the data up and mark it as dirty
                     CCoinsCacheEntry &entry = cacheCoins[it->first];
                     entry.coins.swap(it->second.coins);
                     cachedCoinsUsage += entry.coins.DynamicMemoryUsage();
                     entry.flags = CCoinsCacheEntry::DIRTY;
                     // We can mark it FRESH in the parent if it was FRESH in the
                     // child. Otherwise it might have just been flushed from the
                     // parent's cache and already exist in the grandparent
                     if (it->second.flags & CCoinsCacheEntry::FRESH)
                         entry.flags |= CCoinsCacheEntry::FRESH;
                 }
             } else {
                 // Assert that the child cache entry was not marked FRESH if the
                 // parent cache entry has unspent outputs. If this ever happens,
                 // it means the FRESH flag was misapplied and there is a logic
                 // error in the calling code.
                 if ((it->second.flags & CCoinsCacheEntry::FRESH) &&
                     !itUs->second.coins.IsPruned())
                     throw std::logic_error("FRESH flag misapplied to cache "
                                            "entry for base transaction with "
                                            "spendable outputs");
 
                 // Found the entry in the parent cache
                 if ((itUs->second.flags & CCoinsCacheEntry::FRESH) &&
                     it->second.coins.IsPruned()) {
                     // The grandparent does not have an entry, and the child is
                     // modified and being pruned. This means we can just delete
                     // it from the parent.
                     cachedCoinsUsage -= itUs->second.coins.DynamicMemoryUsage();
                     cacheCoins.erase(itUs);
                 } else {
                     // A normal modification.
                     cachedCoinsUsage -= itUs->second.coins.DynamicMemoryUsage();
                     itUs->second.coins.swap(it->second.coins);
                     cachedCoinsUsage += itUs->second.coins.DynamicMemoryUsage();
                     itUs->second.flags |= CCoinsCacheEntry::DIRTY;
                     // NOTE: It is possible the child has a FRESH flag here in
                     // the event the entry we found in the parent is pruned. But
                     // we must not copy that FRESH flag to the parent as that
                     // pruned state likely still needs to be communicated to the
                     // grandparent.
                 }
             }
         }
         CCoinsMap::iterator itOld = it++;
         mapCoins.erase(itOld);
     }
     hashBlock = hashBlockIn;
     return true;
 }
 
 bool CCoinsViewCache::Flush() {
     bool fOk = base->BatchWrite(cacheCoins, hashBlock);
     cacheCoins.clear();
     cachedCoinsUsage = 0;
     return fOk;
 }
 
 void CCoinsViewCache::Uncache(const uint256 &hash) {
     CCoinsMap::iterator it = cacheCoins.find(hash);
     if (it != cacheCoins.end() && it->second.flags == 0) {
         cachedCoinsUsage -= it->second.coins.DynamicMemoryUsage();
         cacheCoins.erase(it);
     }
 }
 
 unsigned int CCoinsViewCache::GetCacheSize() const {
     return cacheCoins.size();
 }
 
 const CTxOut &CCoinsViewCache::GetOutputFor(const CTxIn &input) const {
     const CCoins *coins = AccessCoins(input.prevout.hash);
     assert(coins && coins->IsAvailable(input.prevout.n));
     return coins->vout[input.prevout.n];
 }
 
 CAmount CCoinsViewCache::GetValueIn(const CTransaction &tx) const {
     if (tx.IsCoinBase()) return 0;
 
     CAmount nResult = 0;
     for (unsigned int i = 0; i < tx.vin.size(); i++)
         nResult += GetOutputFor(tx.vin[i]).nValue;
 
     return nResult;
 }
 
 bool CCoinsViewCache::HaveInputs(const CTransaction &tx) const {
     if (tx.IsCoinBase()) {
         return true;
     }
 
     for (unsigned int i = 0; i < tx.vin.size(); i++) {
         const COutPoint &prevout = tx.vin[i].prevout;
         const CCoins *coins = AccessCoins(prevout.hash);
         if (!coins || !coins->IsAvailable(prevout.n)) {
             return false;
         }
     }
 
     return true;
 }
 
 double CCoinsViewCache::GetPriority(const CTransaction &tx, int nHeight,
                                     CAmount &inChainInputValue) const {
     inChainInputValue = 0;
     if (tx.IsCoinBase()) return 0.0;
     double dResult = 0.0;
     for (const CTxIn &txin : tx.vin) {
         const CCoins *coins = AccessCoins(txin.prevout.hash);
         assert(coins);
         if (!coins->IsAvailable(txin.prevout.n)) continue;
         if (coins->nHeight <= nHeight) {
             dResult += (double)(coins->vout[txin.prevout.n].nValue) *
                        (nHeight - coins->nHeight);
             inChainInputValue += coins->vout[txin.prevout.n].nValue;
         }
     }
     return tx.ComputePriority(dResult);
 }
 
 CCoinsModifier::CCoinsModifier(CCoinsViewCache &cache_, CCoinsMap::iterator it_,
                                size_t usage)
     : cache(cache_), it(it_), cachedCoinUsage(usage) {
     assert(!cache.hasModifier);
     cache.hasModifier = true;
 }
 
 CCoinsModifier::~CCoinsModifier() {
     assert(cache.hasModifier);
     cache.hasModifier = false;
     it->second.coins.Cleanup();
     // Subtract the old usage
     cache.cachedCoinsUsage -= cachedCoinUsage;
     if ((it->second.flags & CCoinsCacheEntry::FRESH) &&
         it->second.coins.IsPruned()) {
         cache.cacheCoins.erase(it);
     } else {
         // If the coin still exists after the modification, add the new usage
         cache.cachedCoinsUsage += it->second.coins.DynamicMemoryUsage();
     }
 }
 
 CCoinsViewCursor::~CCoinsViewCursor() {}
diff --git a/src/coins.h b/src/coins.h
index 7774934ed..1482d7e1f 100644
--- a/src/coins.h
+++ b/src/coins.h
@@ -1,528 +1,546 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_COINS_H
 #define BITCOIN_COINS_H
 
 #include "compressor.h"
 #include "core_memusage.h"
 #include "hash.h"
 #include "memusage.h"
 #include "serialize.h"
 #include "uint256.h"
 
 #include <cassert>
 #include <cstdint>
 
 #include <boost/unordered_map.hpp>
 
 /**
  * A UTXO entry.
  *
  * Serialized format:
  * - VARINT((coinbase ? 1 : 0) | (height << 1))
  * - the non-spent CTxOut (via CTxOutCompressor)
  */
 class Coin {
     //! Unspent transaction output.
     CTxOut out;
 
     //! Whether containing transaction was a coinbase and height at which the
     //! transaction was included into a block.
     uint32_t nHeightAndIsCoinBase;
 
 public:
     //! Empty constructor
     Coin() : nHeightAndIsCoinBase(0) {}
 
     //! Constructor from a CTxOut and height/coinbase information.
     Coin(CTxOut outIn, uint32_t nHeightIn, bool IsCoinbase)
         : out(std::move(outIn)),
           nHeightAndIsCoinBase((nHeightIn << 1) | IsCoinbase) {}
 
     uint32_t GetHeight() const { return nHeightAndIsCoinBase >> 1; }
     bool IsCoinBase() const { return nHeightAndIsCoinBase & 0x01; }
     bool IsSpent() const { return out.IsNull(); }
 
     CTxOut &GetTxOut() { return out; }
     const CTxOut &GetTxOut() const { return out; }
 
     void Clear() {
         out.SetNull();
         nHeightAndIsCoinBase = 0;
     }
 
     template <typename Stream> void Serialize(Stream &s) const {
         assert(!IsSpent());
         ::Serialize(s, VARINT(nHeightAndIsCoinBase));
         ::Serialize(s, CTxOutCompressor(REF(out)));
     }
 
     template <typename Stream> void Unserialize(Stream &s) {
         ::Unserialize(s, VARINT(nHeightAndIsCoinBase));
         ::Unserialize(s, REF(CTxOutCompressor(out)));
     }
 
     size_t DynamicMemoryUsage() const {
         return memusage::DynamicUsage(out.scriptPubKey);
     }
 };
 
 /**
  * Pruned version of CTransaction: only retains metadata and unspent transaction outputs
  *
  * Serialized format:
  * - VARINT(nVersion)
  * - VARINT(nCode)
  * - unspentness bitvector, for vout[2] and further; least significant byte first
  * - the non-spent CTxOuts (via CTxOutCompressor)
  * - VARINT(nHeight)
  *
  * The nCode value consists of:
  * - bit 0: IsCoinBase()
  * - bit 1: vout[0] is not spent
  * - bit 2: vout[1] is not spent
  * - The higher bits encode N, the number of non-zero bytes in the following bitvector.
  *   - In case both bit 1 and bit 2 are unset, they encode N-1, as there must be at
  *     least one non-spent output).
  *
  * Example: 0104835800816115944e077fe7c803cfa57f29b36bf87c1d358bb85e
  *          <><><--------------------------------------------><---->
  *          |  \                  |                             /
  *    version   code             vout[1]                  height
  *
  *    - version = 1
  *    - code = 4 (vout[1] is not spent, and 0 non-zero bytes of bitvector follow)
  *    - unspentness bitvector: as 0 non-zero bytes follow, it has length 0
  *    - vout[1]: 835800816115944e077fe7c803cfa57f29b36bf87c1d35
  *               * 8358: compact amount representation for 60000000000 (600 BTC)
  *               * 00: special txout type pay-to-pubkey-hash
  *               * 816115944e077fe7c803cfa57f29b36bf87c1d35: address uint160
  *    - height = 203998
  *
  *
  * Example: 0109044086ef97d5790061b01caab50f1b8e9c50a5057eb43c2d9563a4eebbd123008c988f1a4a4de2161e0f50aac7f17e7f9555caa486af3b
  *          <><><--><--------------------------------------------------><----------------------------------------------><---->
  *         /  \   \                     |                                                           |                     /
  *  version  code  unspentness       vout[4]                                                     vout[16]           height
  *
  *  - version = 1
  *  - code = 9 (coinbase, neither vout[0] or vout[1] are unspent,
  *                2 (1, +1 because both bit 1 and bit 2 are unset) non-zero bitvector bytes follow)
  *  - unspentness bitvector: bits 2 (0x04) and 14 (0x4000) are set, so vout[2+2] and vout[14+2] are unspent
  *  - vout[4]: 86ef97d5790061b01caab50f1b8e9c50a5057eb43c2d9563a4ee
  *             * 86ef97d579: compact amount representation for 234925952 (2.35 BTC)
  *             * 00: special txout type pay-to-pubkey-hash
  *             * 61b01caab50f1b8e9c50a5057eb43c2d9563a4ee: address uint160
  *  - vout[16]: bbd123008c988f1a4a4de2161e0f50aac7f17e7f9555caa4
  *              * bbd123: compact amount representation for 110397 (0.001 BTC)
  *              * 00: special txout type pay-to-pubkey-hash
  *              * 8c988f1a4a4de2161e0f50aac7f17e7f9555caa4: address uint160
  *  - height = 120891
  *
  * @DISABLE FORMATING FOR THIS COMMENT@
  */
 class CCoins {
 public:
     //! whether transaction is a coinbase
     bool fCoinBase;
 
     //! unspent transaction outputs; spent outputs are .IsNull(); spent outputs
     //! at the end of the array are dropped
     std::vector<CTxOut> vout;
 
     //! at which height this transaction was included in the active block chain
     int nHeight;
 
     //! version of the CTransaction; accesses to this value should probably
     //! check for nHeight as well, as new tx version will probably only be
     //! introduced at certain heights
     int nVersion;
 
     void FromTx(const CTransaction &tx, int nHeightIn) {
         fCoinBase = tx.IsCoinBase();
         vout = tx.vout;
         nHeight = nHeightIn;
         nVersion = tx.nVersion;
         ClearUnspendable();
     }
 
     //! construct a CCoins from a CTransaction, at a given height
     CCoins(const CTransaction &tx, int nHeightIn) { FromTx(tx, nHeightIn); }
 
     void Clear() {
         fCoinBase = false;
         std::vector<CTxOut>().swap(vout);
         nHeight = 0;
         nVersion = 0;
     }
 
     //! empty constructor
     CCoins() : fCoinBase(false), vout(0), nHeight(0), nVersion(0) {}
 
     //! remove spent outputs at the end of vout
     void Cleanup() {
         while (vout.size() > 0 && vout.back().IsNull())
             vout.pop_back();
         if (vout.empty()) std::vector<CTxOut>().swap(vout);
     }
 
     void ClearUnspendable() {
         for (CTxOut &txout : vout) {
             if (txout.scriptPubKey.IsUnspendable()) txout.SetNull();
         }
         Cleanup();
     }
 
     void swap(CCoins &to) {
         std::swap(to.fCoinBase, fCoinBase);
         to.vout.swap(vout);
         std::swap(to.nHeight, nHeight);
         std::swap(to.nVersion, nVersion);
     }
 
     //! equality test
     friend bool operator==(const CCoins &a, const CCoins &b) {
         // Empty CCoins objects are always equal.
         if (a.IsPruned() && b.IsPruned()) return true;
         return a.fCoinBase == b.fCoinBase && a.nHeight == b.nHeight &&
                a.nVersion == b.nVersion && a.vout == b.vout;
     }
 
     friend bool operator!=(const CCoins &a, const CCoins &b) {
         return !(a == b);
     }
 
     void CalcMaskSize(unsigned int &nBytes, unsigned int &nNonzeroBytes) const;
 
     bool IsCoinBase() const { return fCoinBase; }
 
     template <typename Stream> void Serialize(Stream &s) const {
         unsigned int nMaskSize = 0, nMaskCode = 0;
         CalcMaskSize(nMaskSize, nMaskCode);
         bool fFirst = vout.size() > 0 && !vout[0].IsNull();
         bool fSecond = vout.size() > 1 && !vout[1].IsNull();
         assert(fFirst || fSecond || nMaskCode);
         unsigned int nCode = 8 * (nMaskCode - (fFirst || fSecond ? 0 : 1)) +
                              (fCoinBase ? 1 : 0) + (fFirst ? 2 : 0) +
                              (fSecond ? 4 : 0);
         // version
         ::Serialize(s, VARINT(this->nVersion));
         // header code
         ::Serialize(s, VARINT(nCode));
         // spentness bitmask
         for (unsigned int b = 0; b < nMaskSize; b++) {
             unsigned char chAvail = 0;
             for (unsigned int i = 0; i < 8 && 2 + b * 8 + i < vout.size(); i++)
                 if (!vout[2 + b * 8 + i].IsNull()) chAvail |= (1 << i);
             ::Serialize(s, chAvail);
         }
         // txouts themself
         for (unsigned int i = 0; i < vout.size(); i++) {
             if (!vout[i].IsNull())
                 ::Serialize(s, CTxOutCompressor(REF(vout[i])));
         }
         // coinbase height
         ::Serialize(s, VARINT(nHeight));
     }
 
     template <typename Stream> void Unserialize(Stream &s) {
         unsigned int nCode = 0;
         // version
         ::Unserialize(s, VARINT(this->nVersion));
         // header code
         ::Unserialize(s, VARINT(nCode));
         fCoinBase = nCode & 1;
         std::vector<bool> vAvail(2, false);
         vAvail[0] = (nCode & 2) != 0;
         vAvail[1] = (nCode & 4) != 0;
         unsigned int nMaskCode = (nCode / 8) + ((nCode & 6) != 0 ? 0 : 1);
         // spentness bitmask
         while (nMaskCode > 0) {
             unsigned char chAvail = 0;
             ::Unserialize(s, chAvail);
             for (unsigned int p = 0; p < 8; p++) {
                 bool f = (chAvail & (1 << p)) != 0;
                 vAvail.push_back(f);
             }
             if (chAvail != 0) nMaskCode--;
         }
         // txouts themself
         vout.assign(vAvail.size(), CTxOut());
         for (unsigned int i = 0; i < vAvail.size(); i++) {
             if (vAvail[i]) ::Unserialize(s, REF(CTxOutCompressor(vout[i])));
         }
         // coinbase height
         ::Unserialize(s, VARINT(nHeight));
         Cleanup();
     }
 
     //! mark a vout spent
     bool Spend(uint32_t nPos);
 
     //! check whether a particular output is still available
     bool IsAvailable(unsigned int nPos) const {
         return (nPos < vout.size() && !vout[nPos].IsNull());
     }
 
     //! check whether the entire CCoins is spent
     //! note that only !IsPruned() CCoins can be serialized
     bool IsPruned() const {
         for (const CTxOut &out : vout)
             if (!out.IsNull()) return false;
         return true;
     }
 
     size_t DynamicMemoryUsage() const {
         size_t ret = memusage::DynamicUsage(vout);
         for (const CTxOut &out : vout) {
             ret += RecursiveDynamicUsage(out.scriptPubKey);
         }
         return ret;
     }
 };
 
 class SaltedTxidHasher {
 private:
     /** Salt */
     const uint64_t k0, k1;
 
 public:
     SaltedTxidHasher();
 
     /**
      * This *must* return size_t. With Boost 1.46 on 32-bit systems the
      * unordered_map will behave unpredictably if the custom hasher returns a
      * uint64_t, resulting in failures when syncing the chain (#4634).
      */
     size_t operator()(const uint256 &txid) const {
         return SipHashUint256(k0, k1, txid);
     }
 };
 
 struct CCoinsCacheEntry {
     CCoins coins; // The actual cached data.
     unsigned char flags;
 
     enum Flags {
         // This cache entry is potentially different from the version in the
         // parent view.
         DIRTY = (1 << 0),
         // The parent view does not have this entry (or it is pruned).
         FRESH = (1 << 1),
         /* Note that FRESH is a performance optimization with which we can erase
            coins that are fully spent if we know we do not need to flush the
            changes to the parent cache. It is always safe to not mark FRESH if
            that condition is not guaranteed. */
     };
 
     CCoinsCacheEntry() : coins(), flags(0) {}
 };
 
 typedef boost::unordered_map<uint256, CCoinsCacheEntry, SaltedTxidHasher>
     CCoinsMap;
 
 /** Cursor for iterating over CoinsView state */
 class CCoinsViewCursor {
 public:
     CCoinsViewCursor(const uint256 &hashBlockIn) : hashBlock(hashBlockIn) {}
     virtual ~CCoinsViewCursor();
 
     virtual bool GetKey(uint256 &key) const = 0;
     virtual bool GetValue(CCoins &coins) const = 0;
     /* Don't care about GetKeySize here */
     virtual unsigned int GetValueSize() const = 0;
 
     virtual bool Valid() const = 0;
     virtual void Next() = 0;
 
     //! Get best block at the time this cursor was created
     const uint256 &GetBestBlock() const { return hashBlock; }
 
 private:
     uint256 hashBlock;
 };
 
 /** Abstract view on the open txout dataset. */
 class CCoinsView {
+protected:
+    //! Just check whether we have data for a given txid.
+    //! This may (but cannot always) return true for fully spent transactions
+    virtual bool HaveCoins(const uint256 &txid) const;
+
 public:
     //! Retrieve the CCoins (unspent transaction outputs) for a given txid
     virtual bool GetCoins(const uint256 &txid, CCoins &coins) const;
 
-    //! Just check whether we have data for a given txid.
-    //! This may (but cannot always) return true for fully spent transactions
-    virtual bool HaveCoins(const uint256 &txid) const;
+    //! Transitional function to move from HaveCoins to HaveCoin.
+    bool HaveCoins_DONOTUSE(const uint256 &txid) const {
+        return HaveCoins(txid);
+    }
+
+    //! Just check whether we have data for a given outpoint.
+    //! This may (but cannot always) return true for spent outputs.
+    bool HaveCoin(const COutPoint &outpoint) const {
+        CCoins coins;
+        if (!GetCoins(outpoint.hash, coins)) {
+            return false;
+        }
+        return coins.IsAvailable(outpoint.n);
+    }
 
     //! Retrieve the block hash whose state this CCoinsView currently represents
     virtual uint256 GetBestBlock() const;
 
     //! Do a bulk modification (multiple CCoins changes + BestBlock change).
     //! The passed mapCoins can be modified.
     virtual bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock);
 
     //! Get a cursor to iterate over the whole state
     virtual CCoinsViewCursor *Cursor() const;
 
     //! As we use CCoinsViews polymorphically, have a virtual destructor
     virtual ~CCoinsView() {}
 };
 
 /** CCoinsView backed by another CCoinsView */
 class CCoinsViewBacked : public CCoinsView {
 protected:
     CCoinsView *base;
 
+    bool HaveCoins(const uint256 &txid) const;
+
 public:
     CCoinsViewBacked(CCoinsView *viewIn);
     bool GetCoins(const uint256 &txid, CCoins &coins) const;
-    bool HaveCoins(const uint256 &txid) const;
     uint256 GetBestBlock() const;
     void SetBackend(CCoinsView &viewIn);
     bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock);
     CCoinsViewCursor *Cursor() const;
 };
 
 class CCoinsViewCache;
 
 /**
  * A reference to a mutable cache entry. Encapsulating it allows us to run
  *  cleanup code after the modification is finished, and keeping track of
  *  concurrent modifications.
  */
 class CCoinsModifier {
 private:
     CCoinsViewCache &cache;
     CCoinsMap::iterator it;
     // Cached memory usage of the CCoins object before modification.
     size_t cachedCoinUsage;
 
     CCoinsModifier(CCoinsViewCache &cache_, CCoinsMap::iterator it_,
                    size_t usage);
 
 public:
     CCoins *operator->() { return &it->second.coins; }
     CCoins &operator*() { return it->second.coins; }
     ~CCoinsModifier();
     friend class CCoinsViewCache;
 };
 
 /** CCoinsView that adds a memory cache for transactions to another CCoinsView
  */
 class CCoinsViewCache : public CCoinsViewBacked {
 protected:
     /* Whether this cache has an active modifier. */
     bool hasModifier;
 
     /**
      * Make mutable so that we can "fill the cache" even from Get-methods
      * declared as "const".
      */
     mutable uint256 hashBlock;
     mutable CCoinsMap cacheCoins;
 
     /* Cached dynamic memory usage for the inner CCoins objects. */
     mutable size_t cachedCoinsUsage;
 
+    bool HaveCoins(const uint256 &txid) const;
+
 public:
     CCoinsViewCache(CCoinsView *baseIn);
     ~CCoinsViewCache();
 
     // Standard CCoinsView methods
     bool GetCoins(const uint256 &txid, CCoins &coins) const;
-    bool HaveCoins(const uint256 &txid) const;
     uint256 GetBestBlock() const;
     void SetBestBlock(const uint256 &hashBlock);
     bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock);
 
     /**
-     * Check if we have the given tx already loaded in this cache.
-     * The semantics are the same as HaveCoins(), but no calls to
-     * the backing CCoinsView are made.
+     * Check if we have the given utxo already loaded in this cache.
+     * The semantics are the same as HaveCoin(), but no calls to the backing
+     * CCoinsView are made.
      */
-    bool HaveCoinsInCache(const uint256 &txid) const;
+    bool HaveCoinInCache(const COutPoint &outpoint) const;
 
     /**
      * Return a pointer to CCoins in the cache, or nullptr if not found. This is
      * more efficient than GetCoins. Modifications to other cache entries are
      * allowed while accessing the returned pointer.
      */
     const CCoins *AccessCoins(const uint256 &txid) const;
 
     /**
      * Return a modifiable reference to a CCoins. If no entry with the given
      * txid exists, a new one is created. Simultaneous modifications are not
      * allowed.
      */
     CCoinsModifier ModifyCoins(const uint256 &txid);
 
     /**
      * Return a modifiable reference to a CCoins. Assumes that no entry with the
      * given txid exists and creates a new one. This saves a database access in
      * the case where the coins were to be wiped out by FromTx anyway. This
      * should not be called with the 2 historical coinbase duplicate pairs
      * because the new coins are marked fresh, and in the event the duplicate
      * coinbase was spent before a flush, the now pruned coins would not
      * properly overwrite the first coinbase of the pair. Simultaneous
      * modifications are not allowed.
      */
     CCoinsModifier ModifyNewCoins(const uint256 &txid, bool coinbase);
 
     /**
      * Push the modifications applied to this cache to its base.
      * Failure to call this method before destruction will cause the changes to
      * be forgotten. If false is returned, the state of this cache (and its
      * backing view) will be undefined.
      */
     bool Flush();
 
     /**
      * Removes the transaction with the given hash from the cache, if it is
      * not modified.
      */
     void Uncache(const uint256 &txid);
 
     //! Calculate the size of the cache (in number of transactions)
     unsigned int GetCacheSize() const;
 
     //! Calculate the size of the cache (in bytes)
     size_t DynamicMemoryUsage() const;
 
     /**
      * Amount of bitcoins coming in to a transaction
      * Note that lightweight clients may not know anything besides the hash of
      * previous transactions, so may not be able to calculate this.
      *
      * @param[in] tx	transaction for which we are checking input total
      * @return	Sum of value of all inputs (scriptSigs)
      */
     CAmount GetValueIn(const CTransaction &tx) const;
 
     //! Check whether all prevouts of the transaction are present in the UTXO
     //! set represented by this view
     bool HaveInputs(const CTransaction &tx) const;
 
     /**
      * Return priority of tx at height nHeight. Also calculate the sum of the
      * values of the inputs that are already in the chain. These are the inputs
      * that will age and increase priority as new blocks are added to the chain.
      */
     double GetPriority(const CTransaction &tx, int nHeight,
                        CAmount &inChainInputValue) const;
 
     const CTxOut &GetOutputFor(const CTxIn &input) const;
 
     friend class CCoinsModifier;
 
 private:
     CCoinsMap::const_iterator FetchCoins(const uint256 &txid) const;
 
     /**
      * By making the copy constructor private, we prevent accidentally using it
      * when one intends to create a cache on top of a base cache.
      */
     CCoinsViewCache(const CCoinsViewCache &);
 };
 
 #endif // BITCOIN_COINS_H
diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 75586e095..7b2062393 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -1,3660 +1,3663 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include "net_processing.h"
 
 #include "addrman.h"
 #include "arith_uint256.h"
 #include "blockencodings.h"
 #include "chainparams.h"
 #include "config.h"
 #include "consensus/validation.h"
 #include "hash.h"
 #include "init.h"
 #include "merkleblock.h"
 #include "net.h"
 #include "netbase.h"
 #include "netmessagemaker.h"
 #include "policy/fees.h"
 #include "policy/policy.h"
 #include "primitives/block.h"
 #include "primitives/transaction.h"
 #include "random.h"
 #include "tinyformat.h"
 #include "txmempool.h"
 #include "ui_interface.h"
 #include "util.h"
 #include "utilmoneystr.h"
 #include "utilstrencodings.h"
 #include "validation.h"
 #include "validationinterface.h"
 
 #include <boost/range/adaptor/reversed.hpp>
 #include <boost/thread.hpp>
 
 #if defined(NDEBUG)
 #error "Bitcoin cannot be compiled without assertions."
 #endif
 
 // Used only to inform the wallet of when we last received a block.
 std::atomic<int64_t> nTimeBestReceived(0);
 
 struct IteratorComparator {
     template <typename I> bool operator()(const I &a, const I &b) {
         return &(*a) < &(*b);
     }
 };
 
 struct COrphanTx {
     // When modifying, adapt the copy of this definition in tests/DoS_tests.
     CTransactionRef tx;
     NodeId fromPeer;
     int64_t nTimeExpire;
 };
 std::map<uint256, COrphanTx> mapOrphanTransactions GUARDED_BY(cs_main);
 std::map<COutPoint,
          std::set<std::map<uint256, COrphanTx>::iterator, IteratorComparator>>
     mapOrphanTransactionsByPrev GUARDED_BY(cs_main);
 void EraseOrphansFor(NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
 static size_t vExtraTxnForCompactIt = 0;
 static std::vector<std::pair<uint256, CTransactionRef>>
     vExtraTxnForCompact GUARDED_BY(cs_main);
 
 // SHA256("main address relay")[0:8]
 static const uint64_t RANDOMIZER_ID_ADDRESS_RELAY = 0x3cac0035b5866b90ULL;
 
 // Internal stuff
 namespace {
 /** Number of nodes with fSyncStarted. */
 int nSyncStarted = 0;
 
 /**
  * Sources of received blocks, saved to be able to send them reject messages or
  * ban them when processing happens afterwards. Protected by cs_main.
  * Set mapBlockSource[hash].second to false if the node should not be punished
  * if the block is invalid.
  */
 std::map<uint256, std::pair<NodeId, bool>> mapBlockSource;
 
 /**
  * Filter for transactions that were recently rejected by AcceptToMemoryPool.
  * These are not rerequested until the chain tip changes, at which point the
  * entire filter is reset. Protected by cs_main.
  *
  * Without this filter we'd be re-requesting txs from each of our peers,
  * increasing bandwidth consumption considerably. For instance, with 100 peers,
  * half of which relay a tx we don't accept, that might be a 50x bandwidth
  * increase. A flooding attacker attempting to roll-over the filter using
  * minimum-sized, 60byte, transactions might manage to send 1000/sec if we have
  * fast peers, so we pick 120,000 to give our peers a two minute window to send
  * invs to us.
  *
  * Decreasing the false positive rate is fairly cheap, so we pick one in a
  * million to make it highly unlikely for users to have issues with this filter.
  *
  * Memory used: 1.3 MB
  */
 std::unique_ptr<CRollingBloomFilter> recentRejects;
 uint256 hashRecentRejectsChainTip;
 
 /** Blocks that are in flight, and that are in the queue to be downloaded.
  * Protected by cs_main. */
 struct QueuedBlock {
     uint256 hash;
     //!< Optional.
     const CBlockIndex *pindex;
     //!< Whether this block has validated headers at the time of request.
     bool fValidatedHeaders;
     //!< Optional, used for CMPCTBLOCK downloads
     std::unique_ptr<PartiallyDownloadedBlock> partialBlock;
 };
 std::map<uint256, std::pair<NodeId, std::list<QueuedBlock>::iterator>>
     mapBlocksInFlight;
 
 /** Stack of nodes which we have set to announce using compact blocks */
 std::list<NodeId> lNodesAnnouncingHeaderAndIDs;
 
 /** Number of preferable block download peers. */
 int nPreferredDownload = 0;
 
 /** Number of peers from which we're downloading blocks. */
 int nPeersWithValidatedDownloads = 0;
 
 /** Relay map, protected by cs_main. */
 typedef std::map<uint256, CTransactionRef> MapRelay;
 MapRelay mapRelay;
 /** Expiration-time ordered list of (expire time, relay map entry) pairs,
  * protected by cs_main). */
 std::deque<std::pair<int64_t, MapRelay::iterator>> vRelayExpiration;
 } // anon namespace
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // Registration of network node signals.
 //
 
 namespace {
 
 struct CBlockReject {
     unsigned char chRejectCode;
     std::string strRejectReason;
     uint256 hashBlock;
 };
 
 /**
  * Maintain validation-specific state about nodes, protected by cs_main, instead
  * by CNode's own locks. This simplifies asynchronous operation, where
  * processing of incoming data is done after the ProcessMessage call returns,
  * and we're no longer holding the node's locks.
  */
 struct CNodeState {
     //! The peer's address
     const CService address;
     //! Whether we have a fully established connection.
     bool fCurrentlyConnected;
     //! Accumulated misbehaviour score for this peer.
     int nMisbehavior;
     //! Whether this peer should be disconnected and banned (unless
     //! whitelisted).
     bool fShouldBan;
     //! String name of this peer (debugging/logging purposes).
     const std::string name;
     //! List of asynchronously-determined block rejections to notify this peer
     //! about.
     std::vector<CBlockReject> rejects;
     //! The best known block we know this peer has announced.
     const CBlockIndex *pindexBestKnownBlock;
     //! The hash of the last unknown block this peer has announced.
     uint256 hashLastUnknownBlock;
     //! The last full block we both have.
     const CBlockIndex *pindexLastCommonBlock;
     //! The best header we have sent our peer.
     const CBlockIndex *pindexBestHeaderSent;
     //! Length of current-streak of unconnecting headers announcements
     int nUnconnectingHeaders;
     //! Whether we've started headers synchronization with this peer.
     bool fSyncStarted;
     //! Since when we're stalling block download progress (in microseconds), or
     //! 0.
     int64_t nStallingSince;
     std::list<QueuedBlock> vBlocksInFlight;
     //! When the first entry in vBlocksInFlight started downloading. Don't care
     //! when vBlocksInFlight is empty.
     int64_t nDownloadingSince;
     int nBlocksInFlight;
     int nBlocksInFlightValidHeaders;
     //! Whether we consider this a preferred download peer.
     bool fPreferredDownload;
     //! Whether this peer wants invs or headers (when possible) for block
     //! announcements.
     bool fPreferHeaders;
     //! Whether this peer wants invs or cmpctblocks (when possible) for block
     //! announcements.
     bool fPreferHeaderAndIDs;
     /**
      * Whether this peer will send us cmpctblocks if we request them.
      * This is not used to gate request logic, as we really only care about
      * fSupportsDesiredCmpctVersion, but is used as a flag to "lock in" the
      * version of compact blocks we send.
      */
     bool fProvidesHeaderAndIDs;
     /**
      * If we've announced NODE_WITNESS to this peer: whether the peer sends
      * witnesses in cmpctblocks/blocktxns, otherwise: whether this peer sends
      * non-witnesses in cmpctblocks/blocktxns.
      */
     bool fSupportsDesiredCmpctVersion;
 
     CNodeState(CAddress addrIn, std::string addrNameIn)
         : address(addrIn), name(addrNameIn) {
         fCurrentlyConnected = false;
         nMisbehavior = 0;
         fShouldBan = false;
         pindexBestKnownBlock = nullptr;
         hashLastUnknownBlock.SetNull();
         pindexLastCommonBlock = nullptr;
         pindexBestHeaderSent = nullptr;
         nUnconnectingHeaders = 0;
         fSyncStarted = false;
         nStallingSince = 0;
         nDownloadingSince = 0;
         nBlocksInFlight = 0;
         nBlocksInFlightValidHeaders = 0;
         fPreferredDownload = false;
         fPreferHeaders = false;
         fPreferHeaderAndIDs = false;
         fProvidesHeaderAndIDs = false;
         fSupportsDesiredCmpctVersion = false;
     }
 };
 
 /** Map maintaining per-node state. Requires cs_main. */
 std::map<NodeId, CNodeState> mapNodeState;
 
 // Requires cs_main.
 CNodeState *State(NodeId pnode) {
     std::map<NodeId, CNodeState>::iterator it = mapNodeState.find(pnode);
     if (it == mapNodeState.end()) return nullptr;
     return &it->second;
 }
 
 void UpdatePreferredDownload(CNode *node, CNodeState *state) {
     nPreferredDownload -= state->fPreferredDownload;
 
     // Whether this node should be marked as a preferred download node.
     state->fPreferredDownload = (!node->fInbound || node->fWhitelisted) &&
                                 !node->fOneShot && !node->fClient;
 
     nPreferredDownload += state->fPreferredDownload;
 }
 
 void PushNodeVersion(const Config &config, CNode *pnode, CConnman &connman,
                      int64_t nTime) {
     ServiceFlags nLocalNodeServices = pnode->GetLocalServices();
     uint64_t nonce = pnode->GetLocalNonce();
     int nNodeStartingHeight = pnode->GetMyStartingHeight();
     NodeId nodeid = pnode->GetId();
     CAddress addr = pnode->addr;
 
     CAddress addrYou = (addr.IsRoutable() && !IsProxy(addr)
                             ? addr
                             : CAddress(CService(), addr.nServices));
     CAddress addrMe = CAddress(CService(), nLocalNodeServices);
 
     connman.PushMessage(pnode,
                         CNetMsgMaker(INIT_PROTO_VERSION)
                             .Make(NetMsgType::VERSION, PROTOCOL_VERSION,
                                   (uint64_t)nLocalNodeServices, nTime, addrYou,
                                   addrMe, nonce, userAgent(config),
                                   nNodeStartingHeight, ::fRelayTxes));
 
     if (fLogIPs)
         LogPrint("net", "send version message: version %d, blocks=%d, us=%s, "
                         "them=%s, peer=%d\n",
                  PROTOCOL_VERSION, nNodeStartingHeight, addrMe.ToString(),
                  addrYou.ToString(), nodeid);
     else
         LogPrint(
             "net",
             "send version message: version %d, blocks=%d, us=%s, peer=%d\n",
             PROTOCOL_VERSION, nNodeStartingHeight, addrMe.ToString(), nodeid);
 }
 
 void InitializeNode(const Config &config, CNode *pnode, CConnman &connman) {
     CAddress addr = pnode->addr;
     std::string addrName = pnode->GetAddrName();
     NodeId nodeid = pnode->GetId();
     {
         LOCK(cs_main);
         mapNodeState.emplace_hint(
             mapNodeState.end(), std::piecewise_construct,
             std::forward_as_tuple(nodeid),
             std::forward_as_tuple(addr, std::move(addrName)));
     }
     if (!pnode->fInbound) PushNodeVersion(config, pnode, connman, GetTime());
 }
 
 void FinalizeNode(NodeId nodeid, bool &fUpdateConnectionTime) {
     fUpdateConnectionTime = false;
     LOCK(cs_main);
     CNodeState *state = State(nodeid);
 
     if (state->fSyncStarted) nSyncStarted--;
 
     if (state->nMisbehavior == 0 && state->fCurrentlyConnected) {
         fUpdateConnectionTime = true;
     }
 
     for (const QueuedBlock &entry : state->vBlocksInFlight) {
         mapBlocksInFlight.erase(entry.hash);
     }
     EraseOrphansFor(nodeid);
     nPreferredDownload -= state->fPreferredDownload;
     nPeersWithValidatedDownloads -= (state->nBlocksInFlightValidHeaders != 0);
     assert(nPeersWithValidatedDownloads >= 0);
 
     mapNodeState.erase(nodeid);
 
     if (mapNodeState.empty()) {
         // Do a consistency check after the last peer is removed.
         assert(mapBlocksInFlight.empty());
         assert(nPreferredDownload == 0);
         assert(nPeersWithValidatedDownloads == 0);
     }
 }
 
 // Requires cs_main.
 // Returns a bool indicating whether we requested this block.
 // Also used if a block was /not/ received and timed out or started with another
 // peer.
 bool MarkBlockAsReceived(const uint256 &hash) {
     std::map<uint256,
              std::pair<NodeId, std::list<QueuedBlock>::iterator>>::iterator
         itInFlight = mapBlocksInFlight.find(hash);
     if (itInFlight != mapBlocksInFlight.end()) {
         CNodeState *state = State(itInFlight->second.first);
         state->nBlocksInFlightValidHeaders -=
             itInFlight->second.second->fValidatedHeaders;
         if (state->nBlocksInFlightValidHeaders == 0 &&
             itInFlight->second.second->fValidatedHeaders) {
             // Last validated block on the queue was received.
             nPeersWithValidatedDownloads--;
         }
         if (state->vBlocksInFlight.begin() == itInFlight->second.second) {
             // First block on the queue was received, update the start download
             // time for the next one
             state->nDownloadingSince =
                 std::max(state->nDownloadingSince, GetTimeMicros());
         }
         state->vBlocksInFlight.erase(itInFlight->second.second);
         state->nBlocksInFlight--;
         state->nStallingSince = 0;
         mapBlocksInFlight.erase(itInFlight);
         return true;
     }
     return false;
 }
 
 // Requires cs_main.
 // returns false, still setting pit, if the block was already in flight from the
 // same peer pit will only be valid as long as the same cs_main lock is being
 // held.
 static bool
 MarkBlockAsInFlight(const Config &config, NodeId nodeid, const uint256 &hash,
                     const Consensus::Params &consensusParams,
                     const CBlockIndex *pindex = nullptr,
                     std::list<QueuedBlock>::iterator **pit = nullptr) {
     CNodeState *state = State(nodeid);
     assert(state != nullptr);
 
     // Short-circuit most stuff in case its from the same node.
     std::map<uint256,
              std::pair<NodeId, std::list<QueuedBlock>::iterator>>::iterator
         itInFlight = mapBlocksInFlight.find(hash);
     if (itInFlight != mapBlocksInFlight.end() &&
         itInFlight->second.first == nodeid) {
         *pit = &itInFlight->second.second;
         return false;
     }
 
     // Make sure it's not listed somewhere already.
     MarkBlockAsReceived(hash);
 
     std::list<QueuedBlock>::iterator it = state->vBlocksInFlight.insert(
         state->vBlocksInFlight.end(),
         {hash, pindex, pindex != nullptr,
          std::unique_ptr<PartiallyDownloadedBlock>(
              pit ? new PartiallyDownloadedBlock(config, &mempool) : nullptr)});
     state->nBlocksInFlight++;
     state->nBlocksInFlightValidHeaders += it->fValidatedHeaders;
     if (state->nBlocksInFlight == 1) {
         // We're starting a block download (batch) from this peer.
         state->nDownloadingSince = GetTimeMicros();
     }
     if (state->nBlocksInFlightValidHeaders == 1 && pindex != nullptr) {
         nPeersWithValidatedDownloads++;
     }
     itInFlight = mapBlocksInFlight
                      .insert(std::make_pair(hash, std::make_pair(nodeid, it)))
                      .first;
     if (pit) *pit = &itInFlight->second.second;
     return true;
 }
 
 /** Check whether the last unknown block a peer advertised is not yet known. */
 void ProcessBlockAvailability(NodeId nodeid) {
     CNodeState *state = State(nodeid);
     assert(state != nullptr);
 
     if (!state->hashLastUnknownBlock.IsNull()) {
         BlockMap::iterator itOld =
             mapBlockIndex.find(state->hashLastUnknownBlock);
         if (itOld != mapBlockIndex.end() && itOld->second->nChainWork > 0) {
             if (state->pindexBestKnownBlock == nullptr ||
                 itOld->second->nChainWork >=
                     state->pindexBestKnownBlock->nChainWork)
                 state->pindexBestKnownBlock = itOld->second;
             state->hashLastUnknownBlock.SetNull();
         }
     }
 }
 
 /** Update tracking information about which blocks a peer is assumed to have. */
 void UpdateBlockAvailability(NodeId nodeid, const uint256 &hash) {
     CNodeState *state = State(nodeid);
     assert(state != nullptr);
 
     ProcessBlockAvailability(nodeid);
 
     BlockMap::iterator it = mapBlockIndex.find(hash);
     if (it != mapBlockIndex.end() && it->second->nChainWork > 0) {
         // An actually better block was announced.
         if (state->pindexBestKnownBlock == nullptr ||
             it->second->nChainWork >= state->pindexBestKnownBlock->nChainWork)
             state->pindexBestKnownBlock = it->second;
     } else {
         // An unknown block was announced; just assume that the latest one is
         // the best one.
         state->hashLastUnknownBlock = hash;
     }
 }
 
 void MaybeSetPeerAsAnnouncingHeaderAndIDs(NodeId nodeid, CConnman &connman) {
     AssertLockHeld(cs_main);
     CNodeState *nodestate = State(nodeid);
     if (!nodestate) {
         LogPrint("net", "node state unavailable: peer=%d\n", nodeid);
         return;
     }
     if (!nodestate->fProvidesHeaderAndIDs) {
         return;
     }
     for (std::list<NodeId>::iterator it = lNodesAnnouncingHeaderAndIDs.begin();
          it != lNodesAnnouncingHeaderAndIDs.end(); it++) {
         if (*it == nodeid) {
             lNodesAnnouncingHeaderAndIDs.erase(it);
             lNodesAnnouncingHeaderAndIDs.push_back(nodeid);
             return;
         }
     }
     connman.ForNode(nodeid, [&connman](CNode *pfrom) {
         bool fAnnounceUsingCMPCTBLOCK = false;
         uint64_t nCMPCTBLOCKVersion = 1;
         if (lNodesAnnouncingHeaderAndIDs.size() >= 3) {
             // As per BIP152, we only get 3 of our peers to announce
             // blocks using compact encodings.
             connman.ForNode(lNodesAnnouncingHeaderAndIDs.front(),
                             [&connman, fAnnounceUsingCMPCTBLOCK,
                              nCMPCTBLOCKVersion](CNode *pnodeStop) {
                                 connman.PushMessage(
                                     pnodeStop,
                                     CNetMsgMaker(pnodeStop->GetSendVersion())
                                         .Make(NetMsgType::SENDCMPCT,
                                               fAnnounceUsingCMPCTBLOCK,
                                               nCMPCTBLOCKVersion));
                                 return true;
                             });
             lNodesAnnouncingHeaderAndIDs.pop_front();
         }
         fAnnounceUsingCMPCTBLOCK = true;
         connman.PushMessage(pfrom, CNetMsgMaker(pfrom->GetSendVersion())
                                        .Make(NetMsgType::SENDCMPCT,
                                              fAnnounceUsingCMPCTBLOCK,
                                              nCMPCTBLOCKVersion));
         lNodesAnnouncingHeaderAndIDs.push_back(pfrom->GetId());
         return true;
     });
 }
 
 // Requires cs_main
 bool CanDirectFetch(const Consensus::Params &consensusParams) {
     return chainActive.Tip()->GetBlockTime() >
            GetAdjustedTime() - consensusParams.nPowTargetSpacing * 20;
 }
 
 // Requires cs_main
 bool PeerHasHeader(CNodeState *state, const CBlockIndex *pindex) {
     if (state->pindexBestKnownBlock &&
         pindex == state->pindexBestKnownBlock->GetAncestor(pindex->nHeight))
         return true;
     if (state->pindexBestHeaderSent &&
         pindex == state->pindexBestHeaderSent->GetAncestor(pindex->nHeight))
         return true;
     return false;
 }
 
 /**
  * Find the last common ancestor two blocks have.
  * Both pa and pb must be non null.
  */
 const CBlockIndex *LastCommonAncestor(const CBlockIndex *pa,
                                       const CBlockIndex *pb) {
     if (pa->nHeight > pb->nHeight) {
         pa = pa->GetAncestor(pb->nHeight);
     } else if (pb->nHeight > pa->nHeight) {
         pb = pb->GetAncestor(pa->nHeight);
     }
 
     while (pa != pb && pa && pb) {
         pa = pa->pprev;
         pb = pb->pprev;
     }
 
     // Eventually all chain branches meet at the genesis block.
     assert(pa == pb);
     return pa;
 }
 
 /** Update pindexLastCommonBlock and add not-in-flight missing successors to
  * vBlocks, until it has at most count entries. */
 void FindNextBlocksToDownload(NodeId nodeid, unsigned int count,
                               std::vector<const CBlockIndex *> &vBlocks,
                               NodeId &nodeStaller,
                               const Consensus::Params &consensusParams) {
     if (count == 0) return;
 
     vBlocks.reserve(vBlocks.size() + count);
     CNodeState *state = State(nodeid);
     assert(state != nullptr);
 
     // Make sure pindexBestKnownBlock is up to date, we'll need it.
     ProcessBlockAvailability(nodeid);
 
     if (state->pindexBestKnownBlock == nullptr ||
         state->pindexBestKnownBlock->nChainWork <
             chainActive.Tip()->nChainWork) {
         // This peer has nothing interesting.
         return;
     }
 
     if (state->pindexLastCommonBlock == nullptr) {
         // Bootstrap quickly by guessing a parent of our best tip is the forking
         // point. Guessing wrong in either direction is not a problem.
         state->pindexLastCommonBlock = chainActive[std::min(
             state->pindexBestKnownBlock->nHeight, chainActive.Height())];
     }
 
     // If the peer reorganized, our previous pindexLastCommonBlock may not be an
     // ancestor of its current tip anymore. Go back enough to fix that.
     state->pindexLastCommonBlock = LastCommonAncestor(
         state->pindexLastCommonBlock, state->pindexBestKnownBlock);
     if (state->pindexLastCommonBlock == state->pindexBestKnownBlock) return;
 
     std::vector<const CBlockIndex *> vToFetch;
     const CBlockIndex *pindexWalk = state->pindexLastCommonBlock;
     // Never fetch further than the best block we know the peer has, or more
     // than BLOCK_DOWNLOAD_WINDOW + 1 beyond the last linked block we have in
     // common with this peer. The +1 is so we can detect stalling, namely if we
     // would be able to download that next block if the window were 1 larger.
     int nWindowEnd =
         state->pindexLastCommonBlock->nHeight + BLOCK_DOWNLOAD_WINDOW;
     int nMaxHeight =
         std::min<int>(state->pindexBestKnownBlock->nHeight, nWindowEnd + 1);
     NodeId waitingfor = -1;
     while (pindexWalk->nHeight < nMaxHeight) {
         // Read up to 128 (or more, if more blocks than that are needed)
         // successors of pindexWalk (towards pindexBestKnownBlock) into
         // vToFetch. We fetch 128, because CBlockIndex::GetAncestor may be as
         // expensive as iterating over ~100 CBlockIndex* entries anyway.
         int nToFetch = std::min(nMaxHeight - pindexWalk->nHeight,
                                 std::max<int>(count - vBlocks.size(), 128));
         vToFetch.resize(nToFetch);
         pindexWalk = state->pindexBestKnownBlock->GetAncestor(
             pindexWalk->nHeight + nToFetch);
         vToFetch[nToFetch - 1] = pindexWalk;
         for (unsigned int i = nToFetch - 1; i > 0; i--) {
             vToFetch[i - 1] = vToFetch[i]->pprev;
         }
 
         // Iterate over those blocks in vToFetch (in forward direction), adding
         // the ones that are not yet downloaded and not in flight to vBlocks. In
         // the mean time, update pindexLastCommonBlock as long as all ancestors
         // are already downloaded, or if it's already part of our chain (and
         // therefore don't need it even if pruned).
         for (const CBlockIndex *pindex : vToFetch) {
             if (!pindex->IsValid(BLOCK_VALID_TREE)) {
                 // We consider the chain that this peer is on invalid.
                 return;
             }
             if (pindex->nStatus & BLOCK_HAVE_DATA ||
                 chainActive.Contains(pindex)) {
                 if (pindex->nChainTx) state->pindexLastCommonBlock = pindex;
             } else if (mapBlocksInFlight.count(pindex->GetBlockHash()) == 0) {
                 // The block is not already downloaded, and not yet in flight.
                 if (pindex->nHeight > nWindowEnd) {
                     // We reached the end of the window.
                     if (vBlocks.size() == 0 && waitingfor != nodeid) {
                         // We aren't able to fetch anything, but we would be if
                         // the download window was one larger.
                         nodeStaller = waitingfor;
                     }
                     return;
                 }
                 vBlocks.push_back(pindex);
                 if (vBlocks.size() == count) {
                     return;
                 }
             } else if (waitingfor == -1) {
                 // This is the first already-in-flight block.
                 waitingfor = mapBlocksInFlight[pindex->GetBlockHash()].first;
             }
         }
     }
 }
 
 } // anon namespace
 
 bool GetNodeStateStats(NodeId nodeid, CNodeStateStats &stats) {
     LOCK(cs_main);
     CNodeState *state = State(nodeid);
     if (state == nullptr) return false;
     stats.nMisbehavior = state->nMisbehavior;
     stats.nSyncHeight =
         state->pindexBestKnownBlock ? state->pindexBestKnownBlock->nHeight : -1;
     stats.nCommonHeight = state->pindexLastCommonBlock
                               ? state->pindexLastCommonBlock->nHeight
                               : -1;
     for (const QueuedBlock &queue : state->vBlocksInFlight) {
         if (queue.pindex)
             stats.vHeightInFlight.push_back(queue.pindex->nHeight);
     }
     return true;
 }
 
 void RegisterNodeSignals(CNodeSignals &nodeSignals) {
     nodeSignals.ProcessMessages.connect(&ProcessMessages);
     nodeSignals.SendMessages.connect(&SendMessages);
     nodeSignals.InitializeNode.connect(&InitializeNode);
     nodeSignals.FinalizeNode.connect(&FinalizeNode);
 }
 
 void UnregisterNodeSignals(CNodeSignals &nodeSignals) {
     nodeSignals.ProcessMessages.disconnect(&ProcessMessages);
     nodeSignals.SendMessages.disconnect(&SendMessages);
     nodeSignals.InitializeNode.disconnect(&InitializeNode);
     nodeSignals.FinalizeNode.disconnect(&FinalizeNode);
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // mapOrphanTransactions
 //
 
 void AddToCompactExtraTransactions(const CTransactionRef &tx) {
     size_t max_extra_txn = GetArg("-blockreconstructionextratxn",
                                   DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN);
     if (max_extra_txn <= 0) return;
     if (!vExtraTxnForCompact.size()) vExtraTxnForCompact.resize(max_extra_txn);
     vExtraTxnForCompact[vExtraTxnForCompactIt] =
         std::make_pair(tx->GetHash(), tx);
     vExtraTxnForCompactIt = (vExtraTxnForCompactIt + 1) % max_extra_txn;
 }
 
 bool AddOrphanTx(const CTransactionRef &tx, NodeId peer)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     const uint256 &txid = tx->GetId();
     if (mapOrphanTransactions.count(txid)) return false;
 
     // Ignore big transactions, to avoid a send-big-orphans memory exhaustion
     // attack. If a peer has a legitimate large transaction with a missing
     // parent then we assume it will rebroadcast it later, after the parent
     // transaction(s) have been mined or received.
     // 100 orphans, each of which is at most 99,999 bytes big is at most 10
     // megabytes of orphans and somewhat more byprev index (in the worst case):
     unsigned int sz = GetTransactionSize(*tx);
     if (sz >= MAX_STANDARD_TX_SIZE) {
         LogPrint("mempool", "ignoring large orphan tx (size: %u, hash: %s)\n",
                  sz, txid.ToString());
         return false;
     }
 
     auto ret = mapOrphanTransactions.emplace(
         txid, COrphanTx{tx, peer, GetTime() + ORPHAN_TX_EXPIRE_TIME});
     assert(ret.second);
     for (const CTxIn &txin : tx->vin) {
         mapOrphanTransactionsByPrev[txin.prevout].insert(ret.first);
     }
 
     AddToCompactExtraTransactions(tx);
 
     LogPrint("mempool", "stored orphan tx %s (mapsz %u outsz %u)\n",
              txid.ToString(), mapOrphanTransactions.size(),
              mapOrphanTransactionsByPrev.size());
     return true;
 }
 
 int static EraseOrphanTx(uint256 hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     std::map<uint256, COrphanTx>::iterator it =
         mapOrphanTransactions.find(hash);
     if (it == mapOrphanTransactions.end()) return 0;
     for (const CTxIn &txin : it->second.tx->vin) {
         auto itPrev = mapOrphanTransactionsByPrev.find(txin.prevout);
         if (itPrev == mapOrphanTransactionsByPrev.end()) continue;
         itPrev->second.erase(it);
         if (itPrev->second.empty()) mapOrphanTransactionsByPrev.erase(itPrev);
     }
     mapOrphanTransactions.erase(it);
     return 1;
 }
 
 void EraseOrphansFor(NodeId peer) {
     int nErased = 0;
     std::map<uint256, COrphanTx>::iterator iter = mapOrphanTransactions.begin();
     while (iter != mapOrphanTransactions.end()) {
         // Increment to avoid iterator becoming invalid.
         std::map<uint256, COrphanTx>::iterator maybeErase = iter++;
         if (maybeErase->second.fromPeer == peer) {
             nErased += EraseOrphanTx(maybeErase->second.tx->GetId());
         }
     }
     if (nErased > 0)
         LogPrint("mempool", "Erased %d orphan tx from peer=%d\n", nErased,
                  peer);
 }
 
 unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans)
     EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     unsigned int nEvicted = 0;
     static int64_t nNextSweep;
     int64_t nNow = GetTime();
     if (nNextSweep <= nNow) {
         // Sweep out expired orphan pool entries:
         int nErased = 0;
         int64_t nMinExpTime =
             nNow + ORPHAN_TX_EXPIRE_TIME - ORPHAN_TX_EXPIRE_INTERVAL;
         std::map<uint256, COrphanTx>::iterator iter =
             mapOrphanTransactions.begin();
         while (iter != mapOrphanTransactions.end()) {
             std::map<uint256, COrphanTx>::iterator maybeErase = iter++;
             if (maybeErase->second.nTimeExpire <= nNow) {
                 nErased += EraseOrphanTx(maybeErase->second.tx->GetId());
             } else {
                 nMinExpTime =
                     std::min(maybeErase->second.nTimeExpire, nMinExpTime);
             }
         }
         // Sweep again 5 minutes after the next entry that expires in order to
         // batch the linear scan.
         nNextSweep = nMinExpTime + ORPHAN_TX_EXPIRE_INTERVAL;
         if (nErased > 0)
             LogPrint("mempool", "Erased %d orphan tx due to expiration\n",
                      nErased);
     }
     while (mapOrphanTransactions.size() > nMaxOrphans) {
         // Evict a random orphan:
         uint256 randomhash = GetRandHash();
         std::map<uint256, COrphanTx>::iterator it =
             mapOrphanTransactions.lower_bound(randomhash);
         if (it == mapOrphanTransactions.end())
             it = mapOrphanTransactions.begin();
         EraseOrphanTx(it->first);
         ++nEvicted;
     }
     return nEvicted;
 }
 
 // Requires cs_main.
 void Misbehaving(NodeId pnode, int howmuch) {
     if (howmuch == 0) return;
 
     CNodeState *state = State(pnode);
     if (state == nullptr) return;
 
     state->nMisbehavior += howmuch;
     int banscore = GetArg("-banscore", DEFAULT_BANSCORE_THRESHOLD);
     if (state->nMisbehavior >= banscore &&
         state->nMisbehavior - howmuch < banscore) {
         LogPrintf("%s: %s peer=%d (%d -> %d) BAN THRESHOLD EXCEEDED\n",
                   __func__, state->name, pnode, state->nMisbehavior - howmuch,
                   state->nMisbehavior);
         state->fShouldBan = true;
     } else
         LogPrintf("%s: %s peer=%d (%d -> %d)\n", __func__, state->name, pnode,
                   state->nMisbehavior - howmuch, state->nMisbehavior);
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // blockchain -> download logic notification
 //
 
 PeerLogicValidation::PeerLogicValidation(CConnman *connmanIn)
     : connman(connmanIn) {
     // Initialize global variables that cannot be constructed at startup.
     recentRejects.reset(new CRollingBloomFilter(120000, 0.000001));
 }
 
 void PeerLogicValidation::SyncTransaction(const CTransaction &tx,
                                           const CBlockIndex *pindex,
                                           int nPosInBlock) {
     if (nPosInBlock == CMainSignals::SYNC_TRANSACTION_NOT_IN_BLOCK) return;
 
     LOCK(cs_main);
 
     std::vector<uint256> vOrphanErase;
     // Which orphan pool entries must we evict?
     for (size_t j = 0; j < tx.vin.size(); j++) {
         auto itByPrev = mapOrphanTransactionsByPrev.find(tx.vin[j].prevout);
         if (itByPrev == mapOrphanTransactionsByPrev.end()) continue;
         for (auto mi = itByPrev->second.begin(); mi != itByPrev->second.end();
              ++mi) {
             const CTransaction &orphanTx = *(*mi)->second.tx;
             const uint256 &orphanId = orphanTx.GetId();
             vOrphanErase.push_back(orphanId);
         }
     }
 
     // Erase orphan transactions include or precluded by this block
     if (vOrphanErase.size()) {
         int nErased = 0;
         for (uint256 &orphanId : vOrphanErase) {
             nErased += EraseOrphanTx(orphanId);
         }
         LogPrint("mempool",
                  "Erased %d orphan tx included or conflicted by block\n",
                  nErased);
     }
 }
 
 static CCriticalSection cs_most_recent_block;
 static std::shared_ptr<const CBlock> most_recent_block;
 static std::shared_ptr<const CBlockHeaderAndShortTxIDs>
     most_recent_compact_block;
 static uint256 most_recent_block_hash;
 
 void PeerLogicValidation::NewPoWValidBlock(
     const CBlockIndex *pindex, const std::shared_ptr<const CBlock> &pblock) {
     std::shared_ptr<const CBlockHeaderAndShortTxIDs> pcmpctblock =
         std::make_shared<const CBlockHeaderAndShortTxIDs>(*pblock);
     const CNetMsgMaker msgMaker(PROTOCOL_VERSION);
 
     LOCK(cs_main);
 
     static int nHighestFastAnnounce = 0;
     if (pindex->nHeight <= nHighestFastAnnounce) return;
     nHighestFastAnnounce = pindex->nHeight;
 
     uint256 hashBlock(pblock->GetHash());
 
     {
         LOCK(cs_most_recent_block);
         most_recent_block_hash = hashBlock;
         most_recent_block = pblock;
         most_recent_compact_block = pcmpctblock;
     }
 
     connman->ForEachNode([this, &pcmpctblock, pindex, &msgMaker,
                           &hashBlock](CNode *pnode) {
         // TODO: Avoid the repeated-serialization here
         if (pnode->nVersion < INVALID_CB_NO_BAN_VERSION || pnode->fDisconnect)
             return;
         ProcessBlockAvailability(pnode->GetId());
         CNodeState &state = *State(pnode->GetId());
         // If the peer has, or we announced to them the previous block already,
         // but we don't think they have this one, go ahead and announce it.
         if (state.fPreferHeaderAndIDs && !PeerHasHeader(&state, pindex) &&
             PeerHasHeader(&state, pindex->pprev)) {
 
             LogPrint("net", "%s sending header-and-ids %s to peer=%d\n",
                      "PeerLogicValidation::NewPoWValidBlock",
                      hashBlock.ToString(), pnode->id);
             connman->PushMessage(
                 pnode, msgMaker.Make(NetMsgType::CMPCTBLOCK, *pcmpctblock));
             state.pindexBestHeaderSent = pindex;
         }
     });
 }
 
 void PeerLogicValidation::UpdatedBlockTip(const CBlockIndex *pindexNew,
                                           const CBlockIndex *pindexFork,
                                           bool fInitialDownload) {
     const int nNewHeight = pindexNew->nHeight;
     connman->SetBestHeight(nNewHeight);
 
     if (!fInitialDownload) {
         // Find the hashes of all blocks that weren't previously in the best
         // chain.
         std::vector<uint256> vHashes;
         const CBlockIndex *pindexToAnnounce = pindexNew;
         while (pindexToAnnounce != pindexFork) {
             vHashes.push_back(pindexToAnnounce->GetBlockHash());
             pindexToAnnounce = pindexToAnnounce->pprev;
             if (vHashes.size() == MAX_BLOCKS_TO_ANNOUNCE) {
                 // Limit announcements in case of a huge reorganization. Rely on
                 // the peer's synchronization mechanism in that case.
                 break;
             }
         }
         // Relay inventory, but don't relay old inventory during initial block
         // download.
         connman->ForEachNode([nNewHeight, &vHashes](CNode *pnode) {
             if (nNewHeight > (pnode->nStartingHeight != -1
                                   ? pnode->nStartingHeight - 2000
                                   : 0)) {
                 for (const uint256 &hash : boost::adaptors::reverse(vHashes)) {
                     pnode->PushBlockHash(hash);
                 }
             }
         });
         connman->WakeMessageHandler();
     }
 
     nTimeBestReceived = GetTime();
 }
 
 void PeerLogicValidation::BlockChecked(const CBlock &block,
                                        const CValidationState &state) {
     LOCK(cs_main);
 
     const uint256 hash(block.GetHash());
     std::map<uint256, std::pair<NodeId, bool>>::iterator it =
         mapBlockSource.find(hash);
 
     int nDoS = 0;
     if (state.IsInvalid(nDoS)) {
         if (it != mapBlockSource.end() && State(it->second.first)) {
             // Blocks are never rejected with internal reject codes.
             assert(state.GetRejectCode() < REJECT_INTERNAL);
             CBlockReject reject = {
                 (unsigned char)state.GetRejectCode(),
                 state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH),
                 hash};
             State(it->second.first)->rejects.push_back(reject);
             if (nDoS > 0 && it->second.second)
                 Misbehaving(it->second.first, nDoS);
         }
     }
     // Check that:
     // 1. The block is valid
     // 2. We're not in initial block download
     // 3. This is currently the best block we're aware of. We haven't updated
     //    the tip yet so we have no way to check this directly here. Instead we
     //    just check that there are currently no other blocks in flight.
     else if (state.IsValid() && !IsInitialBlockDownload() &&
              mapBlocksInFlight.count(hash) == mapBlocksInFlight.size()) {
         if (it != mapBlockSource.end()) {
             MaybeSetPeerAsAnnouncingHeaderAndIDs(it->second.first, *connman);
         }
     }
     if (it != mapBlockSource.end()) mapBlockSource.erase(it);
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // Messages
 //
 
 bool static AlreadyHave(const CInv &inv) EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     switch (inv.type) {
         case MSG_TX: {
             assert(recentRejects);
             if (chainActive.Tip()->GetBlockHash() !=
                 hashRecentRejectsChainTip) {
                 // If the chain tip has changed previously rejected transactions
                 // might be now valid, e.g. due to a nLockTime'd tx becoming
                 // valid, or a double-spend. Reset the rejects filter and give
                 // those txs a second chance.
                 hashRecentRejectsChainTip = chainActive.Tip()->GetBlockHash();
                 recentRejects->reset();
             }
 
-            // Use pcoinsTip->HaveCoinsInCache as a quick approximation to
+            // Use pcoinsTip->HaveCoinInCache as a quick approximation to
             // exclude requesting or processing some txs which have already been
-            // included in a block.
+            // included in a block. As this is best effort, we only check for
+            // output 0 and 1. This works well enough in practice and we get
+            // diminishing returns with 2 onward.
             return recentRejects->contains(inv.hash) ||
                    mempool.exists(inv.hash) ||
                    mapOrphanTransactions.count(inv.hash) ||
-                   pcoinsTip->HaveCoinsInCache(inv.hash);
+                   pcoinsTip->HaveCoinInCache(COutPoint(inv.hash, 0)) ||
+                   pcoinsTip->HaveCoinInCache(COutPoint(inv.hash, 1));
         }
         case MSG_BLOCK:
             return mapBlockIndex.count(inv.hash);
     }
     // Don't know what it is, just say we already got one
     return true;
 }
 
 static void RelayTransaction(const CTransaction &tx, CConnman &connman) {
     CInv inv(MSG_TX, tx.GetId());
     connman.ForEachNode([&inv](CNode *pnode) { pnode->PushInventory(inv); });
 }
 
 static void RelayAddress(const CAddress &addr, bool fReachable,
                          CConnman &connman) {
     // Limited relaying of addresses outside our network(s)
     unsigned int nRelayNodes = fReachable ? 2 : 1;
 
     // Relay to a limited number of other nodes.
     // Use deterministic randomness to send to the same nodes for 24 hours at a
     // time so the addrKnowns of the chosen nodes prevent repeats.
     uint64_t hashAddr = addr.GetHash();
     const CSipHasher hasher =
         connman.GetDeterministicRandomizer(RANDOMIZER_ID_ADDRESS_RELAY)
             .Write(hashAddr << 32)
             .Write((GetTime() + hashAddr) / (24 * 60 * 60));
     FastRandomContext insecure_rand;
 
     std::array<std::pair<uint64_t, CNode *>, 2> best{
         {{0, nullptr}, {0, nullptr}}};
     assert(nRelayNodes <= best.size());
 
     auto sortfunc = [&best, &hasher, nRelayNodes](CNode *pnode) {
         if (pnode->nVersion >= CADDR_TIME_VERSION) {
             uint64_t hashKey = CSipHasher(hasher).Write(pnode->id).Finalize();
             for (unsigned int i = 0; i < nRelayNodes; i++) {
                 if (hashKey > best[i].first) {
                     std::copy(best.begin() + i, best.begin() + nRelayNodes - 1,
                               best.begin() + i + 1);
                     best[i] = std::make_pair(hashKey, pnode);
                     break;
                 }
             }
         }
     };
 
     auto pushfunc = [&addr, &best, nRelayNodes, &insecure_rand] {
         for (unsigned int i = 0; i < nRelayNodes && best[i].first != 0; i++) {
             best[i].second->PushAddress(addr, insecure_rand);
         }
     };
 
     connman.ForEachNodeThen(std::move(sortfunc), std::move(pushfunc));
 }
 
 void static ProcessGetData(const Config &config, CNode *pfrom,
                            const Consensus::Params &consensusParams,
                            CConnman &connman,
                            const std::atomic<bool> &interruptMsgProc) {
     std::deque<CInv>::iterator it = pfrom->vRecvGetData.begin();
     std::vector<CInv> vNotFound;
     const CNetMsgMaker msgMaker(pfrom->GetSendVersion());
     LOCK(cs_main);
 
     while (it != pfrom->vRecvGetData.end()) {
         // Don't bother if send buffer is too full to respond anyway.
         if (pfrom->fPauseSend) break;
 
         const CInv &inv = *it;
         {
             if (interruptMsgProc) return;
 
             it++;
 
             if (inv.type == MSG_BLOCK || inv.type == MSG_FILTERED_BLOCK ||
                 inv.type == MSG_CMPCT_BLOCK) {
                 bool send = false;
                 BlockMap::iterator mi = mapBlockIndex.find(inv.hash);
                 if (mi != mapBlockIndex.end()) {
                     if (mi->second->nChainTx &&
                         !mi->second->IsValid(BLOCK_VALID_SCRIPTS) &&
                         mi->second->IsValid(BLOCK_VALID_TREE)) {
                         // If we have the block and all of its parents, but have
                         // not yet validated it, we might be in the middle of
                         // connecting it (ie in the unlock of cs_main before
                         // ActivateBestChain but after AcceptBlock). In this
                         // case, we need to run ActivateBestChain prior to
                         // checking the relay conditions below.
                         std::shared_ptr<const CBlock> a_recent_block;
                         {
                             LOCK(cs_most_recent_block);
                             a_recent_block = most_recent_block;
                         }
                         CValidationState dummy;
                         ActivateBestChain(config, dummy, a_recent_block);
                     }
                     if (chainActive.Contains(mi->second)) {
                         send = true;
                     } else {
                         static const int nOneMonth = 30 * 24 * 60 * 60;
                         // To prevent fingerprinting attacks, only send blocks
                         // outside of the active chain if they are valid, and no
                         // more than a month older (both in time, and in best
                         // equivalent proof of work) than the best header chain
                         // we know about.
                         send = mi->second->IsValid(BLOCK_VALID_SCRIPTS) &&
                                (pindexBestHeader != nullptr) &&
                                (pindexBestHeader->GetBlockTime() -
                                     mi->second->GetBlockTime() <
                                 nOneMonth) &&
                                (GetBlockProofEquivalentTime(
                                     *pindexBestHeader, *mi->second,
                                     *pindexBestHeader,
                                     consensusParams) < nOneMonth);
                         if (!send) {
                             LogPrintf("%s: ignoring request from peer=%i for "
                                       "old block that isn't in the main "
                                       "chain\n",
                                       __func__, pfrom->GetId());
                         }
                     }
                 }
 
                 // Disconnect node in case we have reached the outbound limit
                 // for serving historical blocks never disconnect whitelisted
                 // nodes.
                 // assume > 1 week = historical
                 static const int nOneWeek = 7 * 24 * 60 * 60;
                 if (send && connman.OutboundTargetReached(true) &&
                     (((pindexBestHeader != nullptr) &&
                       (pindexBestHeader->GetBlockTime() -
                            mi->second->GetBlockTime() >
                        nOneWeek)) ||
                      inv.type == MSG_FILTERED_BLOCK) &&
                     !pfrom->fWhitelisted) {
                     LogPrint("net", "historical block serving limit reached, "
                                     "disconnect peer=%d\n",
                              pfrom->GetId());
 
                     // disconnect node
                     pfrom->fDisconnect = true;
                     send = false;
                 }
                 // Pruned nodes may have deleted the block, so check whether
                 // it's available before trying to send.
                 if (send && (mi->second->nStatus & BLOCK_HAVE_DATA)) {
                     // Send block from disk
                     CBlock block;
                     if (!ReadBlockFromDisk(block, (*mi).second,
                                            consensusParams))
                         assert(!"cannot load block from disk");
                     if (inv.type == MSG_BLOCK)
                         connman.PushMessage(
                             pfrom, msgMaker.Make(NetMsgType::BLOCK, block));
                     else if (inv.type == MSG_FILTERED_BLOCK) {
                         bool sendMerkleBlock = false;
                         CMerkleBlock merkleBlock;
                         {
                             LOCK(pfrom->cs_filter);
                             if (pfrom->pfilter) {
                                 sendMerkleBlock = true;
                                 merkleBlock =
                                     CMerkleBlock(block, *pfrom->pfilter);
                             }
                         }
                         if (sendMerkleBlock) {
                             connman.PushMessage(
                                 pfrom, msgMaker.Make(NetMsgType::MERKLEBLOCK,
                                                      merkleBlock));
                             // CMerkleBlock just contains hashes, so also push
                             // any transactions in the block the client did not
                             // see. This avoids hurting performance by
                             // pointlessly requiring a round-trip. Note that
                             // there is currently no way for a node to request
                             // any single transactions we didn't send here -
                             // they must either disconnect and retry or request
                             // the full block. Thus, the protocol spec specified
                             // allows for us to provide duplicate txn here,
                             // however we MUST always provide at least what the
                             // remote peer needs.
                             typedef std::pair<unsigned int, uint256> PairType;
                             for (PairType &pair : merkleBlock.vMatchedTxn) {
                                 connman.PushMessage(
                                     pfrom,
                                     msgMaker.Make(NetMsgType::TX,
                                                   *block.vtx[pair.first]));
                             }
                         }
                         // else
                         // no response
                     } else if (inv.type == MSG_CMPCT_BLOCK) {
                         // If a peer is asking for old blocks, we're almost
                         // guaranteed they won't have a useful mempool to match
                         // against a compact block, and we don't feel like
                         // constructing the object for them, so instead we
                         // respond with the full, non-compact block.
                         int nSendFlags = 0;
                         if (CanDirectFetch(consensusParams) &&
                             mi->second->nHeight >=
                                 chainActive.Height() - MAX_CMPCTBLOCK_DEPTH) {
                             CBlockHeaderAndShortTxIDs cmpctblock(block);
                             connman.PushMessage(
                                 pfrom, msgMaker.Make(nSendFlags,
                                                      NetMsgType::CMPCTBLOCK,
                                                      cmpctblock));
                         } else
                             connman.PushMessage(
                                 pfrom, msgMaker.Make(nSendFlags,
                                                      NetMsgType::BLOCK, block));
                     }
 
                     // Trigger the peer node to send a getblocks request for the
                     // next batch of inventory.
                     if (inv.hash == pfrom->hashContinue) {
                         // Bypass PushInventory, this must send even if
                         // redundant, and we want it right after the last block
                         // so they don't wait for other stuff first.
                         std::vector<CInv> vInv;
                         vInv.push_back(
                             CInv(MSG_BLOCK, chainActive.Tip()->GetBlockHash()));
                         connman.PushMessage(
                             pfrom, msgMaker.Make(NetMsgType::INV, vInv));
                         pfrom->hashContinue.SetNull();
                     }
                 }
             } else if (inv.type == MSG_TX) {
                 // Send stream from relay memory
                 bool push = false;
                 auto mi = mapRelay.find(inv.hash);
                 int nSendFlags = 0;
                 if (mi != mapRelay.end()) {
                     connman.PushMessage(
                         pfrom,
                         msgMaker.Make(nSendFlags, NetMsgType::TX, *mi->second));
                     push = true;
                 } else if (pfrom->timeLastMempoolReq) {
                     auto txinfo = mempool.info(inv.hash);
                     // To protect privacy, do not answer getdata using the
                     // mempool when that TX couldn't have been INVed in reply to
                     // a MEMPOOL request.
                     if (txinfo.tx &&
                         txinfo.nTime <= pfrom->timeLastMempoolReq) {
                         connman.PushMessage(pfrom, msgMaker.Make(nSendFlags,
                                                                  NetMsgType::TX,
                                                                  *txinfo.tx));
                         push = true;
                     }
                 }
                 if (!push) {
                     vNotFound.push_back(inv);
                 }
             }
 
             // Track requests for our stuff.
             GetMainSignals().Inventory(inv.hash);
 
             if (inv.type == MSG_BLOCK || inv.type == MSG_FILTERED_BLOCK ||
                 inv.type == MSG_CMPCT_BLOCK)
                 break;
         }
     }
 
     pfrom->vRecvGetData.erase(pfrom->vRecvGetData.begin(), it);
 
     if (!vNotFound.empty()) {
         // Let the peer know that we didn't find what it asked for, so it
         // doesn't have to wait around forever. Currently only SPV clients
         // actually care about this message: it's needed when they are
         // recursively walking the dependencies of relevant unconfirmed
         // transactions. SPV clients want to do that because they want to know
         // about (and store and rebroadcast and risk analyze) the dependencies
         // of transactions relevant to them, without having to download the
         // entire memory pool.
         connman.PushMessage(pfrom,
                             msgMaker.Make(NetMsgType::NOTFOUND, vNotFound));
     }
 }
 
 uint32_t GetFetchFlags(CNode *pfrom, const CBlockIndex *pprev,
                        const Consensus::Params &chainparams) {
     uint32_t nFetchFlags = 0;
     return nFetchFlags;
 }
 
 inline void static SendBlockTransactions(const CBlock &block,
                                          const BlockTransactionsRequest &req,
                                          CNode *pfrom, CConnman &connman) {
     BlockTransactions resp(req);
     for (size_t i = 0; i < req.indexes.size(); i++) {
         if (req.indexes[i] >= block.vtx.size()) {
             LOCK(cs_main);
             Misbehaving(pfrom->GetId(), 100);
             LogPrintf(
                 "Peer %d sent us a getblocktxn with out-of-bounds tx indices",
                 pfrom->id);
             return;
         }
         resp.txn[i] = block.vtx[req.indexes[i]];
     }
     LOCK(cs_main);
     const CNetMsgMaker msgMaker(pfrom->GetSendVersion());
     int nSendFlags = 0;
     connman.PushMessage(pfrom,
                         msgMaker.Make(nSendFlags, NetMsgType::BLOCKTXN, resp));
 }
 
 bool static ProcessMessage(const Config &config, CNode *pfrom,
                            const std::string &strCommand, CDataStream &vRecv,
                            int64_t nTimeReceived,
                            const CChainParams &chainparams, CConnman &connman,
                            const std::atomic<bool> &interruptMsgProc) {
     LogPrint("net", "received: %s (%u bytes) peer=%d\n",
              SanitizeString(strCommand), vRecv.size(), pfrom->id);
     if (IsArgSet("-dropmessagestest") &&
         GetRand(GetArg("-dropmessagestest", 0)) == 0) {
         LogPrintf("dropmessagestest DROPPING RECV MESSAGE\n");
         return true;
     }
 
     if (!(pfrom->GetLocalServices() & NODE_BLOOM) &&
         (strCommand == NetMsgType::FILTERLOAD ||
          strCommand == NetMsgType::FILTERADD)) {
         if (pfrom->nVersion >= NO_BLOOM_VERSION) {
             LOCK(cs_main);
             Misbehaving(pfrom->GetId(), 100);
             return false;
         } else {
             pfrom->fDisconnect = true;
             return false;
         }
     }
 
     if (strCommand == NetMsgType::REJECT) {
         if (fDebug) {
             try {
                 std::string strMsg;
                 unsigned char ccode;
                 std::string strReason;
                 vRecv >> LIMITED_STRING(strMsg, CMessageHeader::COMMAND_SIZE) >>
                     ccode >>
                     LIMITED_STRING(strReason, MAX_REJECT_MESSAGE_LENGTH);
 
                 std::ostringstream ss;
                 ss << strMsg << " code " << itostr(ccode) << ": " << strReason;
 
                 if (strMsg == NetMsgType::BLOCK || strMsg == NetMsgType::TX) {
                     uint256 hash;
                     vRecv >> hash;
                     ss << ": hash " << hash.ToString();
                 }
                 LogPrint("net", "Reject %s\n", SanitizeString(ss.str()));
             } catch (const std::ios_base::failure &) {
                 // Avoid feedback loops by preventing reject messages from
                 // triggering a new reject message.
                 LogPrint("net", "Unparseable reject message received\n");
             }
         }
     }
 
     else if (strCommand == NetMsgType::VERSION) {
         // Each connection can only send one version message
         if (pfrom->nVersion != 0) {
             connman.PushMessage(
                 pfrom,
                 CNetMsgMaker(INIT_PROTO_VERSION)
                     .Make(NetMsgType::REJECT, strCommand, REJECT_DUPLICATE,
                           std::string("Duplicate version message")));
             LOCK(cs_main);
             Misbehaving(pfrom->GetId(), 1);
             return false;
         }
 
         int64_t nTime;
         CAddress addrMe;
         CAddress addrFrom;
         uint64_t nNonce = 1;
         uint64_t nServiceInt;
         ServiceFlags nServices;
         int nVersion;
         int nSendVersion;
         std::string strSubVer;
         std::string cleanSubVer;
         int nStartingHeight = -1;
         bool fRelay = true;
 
         vRecv >> nVersion >> nServiceInt >> nTime >> addrMe;
         nSendVersion = std::min(nVersion, PROTOCOL_VERSION);
         nServices = ServiceFlags(nServiceInt);
         if (!pfrom->fInbound) {
             connman.SetServices(pfrom->addr, nServices);
         }
         if (pfrom->nServicesExpected & ~nServices) {
             LogPrint("net", "peer=%d does not offer the expected services "
                             "(%08x offered, %08x expected); disconnecting\n",
                      pfrom->id, nServices, pfrom->nServicesExpected);
             connman.PushMessage(
                 pfrom,
                 CNetMsgMaker(INIT_PROTO_VERSION)
                     .Make(NetMsgType::REJECT, strCommand, REJECT_NONSTANDARD,
                           strprintf("Expected to offer services %08x",
                                     pfrom->nServicesExpected)));
             pfrom->fDisconnect = true;
             return false;
         }
 
         if (nVersion < MIN_PEER_PROTO_VERSION) {
             // disconnect from peers older than this proto version
             LogPrintf("peer=%d using obsolete version %i; disconnecting\n",
                       pfrom->id, nVersion);
             connman.PushMessage(
                 pfrom,
                 CNetMsgMaker(INIT_PROTO_VERSION)
                     .Make(NetMsgType::REJECT, strCommand, REJECT_OBSOLETE,
                           strprintf("Version must be %d or greater",
                                     MIN_PEER_PROTO_VERSION)));
             pfrom->fDisconnect = true;
             return false;
         }
 
         if (!vRecv.empty()) vRecv >> addrFrom >> nNonce;
         if (!vRecv.empty()) {
             vRecv >> LIMITED_STRING(strSubVer, MAX_SUBVERSION_LENGTH);
             cleanSubVer = SanitizeString(strSubVer);
         }
         if (!vRecv.empty()) {
             vRecv >> nStartingHeight;
         }
         if (!vRecv.empty()) vRecv >> fRelay;
         // Disconnect if we connected to ourself
         if (pfrom->fInbound && !connman.CheckIncomingNonce(nNonce)) {
             LogPrintf("connected to self at %s, disconnecting\n",
                       pfrom->addr.ToString());
             pfrom->fDisconnect = true;
             return true;
         }
 
         if (pfrom->fInbound && addrMe.IsRoutable()) {
             SeenLocal(addrMe);
         }
 
         // Be shy and don't send version until we hear
         if (pfrom->fInbound)
             PushNodeVersion(config, pfrom, connman, GetAdjustedTime());
 
         connman.PushMessage(
             pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::VERACK));
 
         pfrom->nServices = nServices;
         pfrom->SetAddrLocal(addrMe);
         {
             LOCK(pfrom->cs_SubVer);
             pfrom->strSubVer = strSubVer;
             pfrom->cleanSubVer = cleanSubVer;
         }
         pfrom->nStartingHeight = nStartingHeight;
         pfrom->fClient = !(nServices & NODE_NETWORK);
         {
             LOCK(pfrom->cs_filter);
             pfrom->fRelayTxes =
                 fRelay; // set to true after we get the first filter* message
         }
 
         // Change version
         pfrom->SetSendVersion(nSendVersion);
         pfrom->nVersion = nVersion;
 
         // Potentially mark this peer as a preferred download peer.
         {
             LOCK(cs_main);
             UpdatePreferredDownload(pfrom, State(pfrom->GetId()));
         }
 
         if (!pfrom->fInbound) {
             // Advertise our address
             if (fListen && !IsInitialBlockDownload()) {
                 CAddress addr =
                     GetLocalAddress(&pfrom->addr, pfrom->GetLocalServices());
                 FastRandomContext insecure_rand;
                 if (addr.IsRoutable()) {
                     LogPrint("net", "ProcessMessages: advertising address %s\n",
                              addr.ToString());
                     pfrom->PushAddress(addr, insecure_rand);
                 } else if (IsPeerAddrLocalGood(pfrom)) {
                     addr.SetIP(addrMe);
                     LogPrint("net", "ProcessMessages: advertising address %s\n",
                              addr.ToString());
                     pfrom->PushAddress(addr, insecure_rand);
                 }
             }
 
             // Get recent addresses
             if (pfrom->fOneShot || pfrom->nVersion >= CADDR_TIME_VERSION ||
                 connman.GetAddressCount() < 1000) {
                 connman.PushMessage(
                     pfrom,
                     CNetMsgMaker(nSendVersion).Make(NetMsgType::GETADDR));
                 pfrom->fGetAddr = true;
             }
             connman.MarkAddressGood(pfrom->addr);
         }
 
         std::string remoteAddr;
         if (fLogIPs) remoteAddr = ", peeraddr=" + pfrom->addr.ToString();
 
         LogPrintf("receive version message: %s: version %d, blocks=%d, us=%s, "
                   "peer=%d%s\n",
                   cleanSubVer, pfrom->nVersion, pfrom->nStartingHeight,
                   addrMe.ToString(), pfrom->id, remoteAddr);
 
         int64_t nTimeOffset = nTime - GetTime();
         pfrom->nTimeOffset = nTimeOffset;
         AddTimeData(pfrom->addr, nTimeOffset);
 
         // If the peer is old enough to have the old alert system, send it the
         // final alert.
         if (pfrom->nVersion <= 70012) {
             CDataStream finalAlert(
                 ParseHex("60010000000000000000000000ffffff7f00000000ffffff7ffef"
                          "fff7f01ffffff7f00000000ffffff7f00ffffff7f002f55524745"
                          "4e543a20416c657274206b657920636f6d70726f6d697365642c2"
                          "075706772616465207265717569726564004630440220653febd6"
                          "410f470f6bae11cad19c48413becb1ac2c17f908fd0fd53bdc3ab"
                          "d5202206d0e9c96fe88d4a0f01ed9dedae2b6f9e00da94cad0fec"
                          "aae66ecf689bf71b50"),
                 SER_NETWORK, PROTOCOL_VERSION);
             connman.PushMessage(
                 pfrom, CNetMsgMaker(nSendVersion).Make("alert", finalAlert));
         }
 
         // Feeler connections exist only to verify if address is online.
         if (pfrom->fFeeler) {
             assert(pfrom->fInbound == false);
             pfrom->fDisconnect = true;
         }
         return true;
     }
 
     else if (pfrom->nVersion == 0) {
         // Must have a version message before anything else
         LOCK(cs_main);
         Misbehaving(pfrom->GetId(), 1);
         return false;
     }
 
     // At this point, the outgoing message serialization version can't change.
     const CNetMsgMaker msgMaker(pfrom->GetSendVersion());
 
     if (strCommand == NetMsgType::VERACK) {
         pfrom->SetRecvVersion(
             std::min(pfrom->nVersion.load(), PROTOCOL_VERSION));
 
         if (!pfrom->fInbound) {
             // Mark this node as currently connected, so we update its timestamp
             // later.
             LOCK(cs_main);
             State(pfrom->GetId())->fCurrentlyConnected = true;
         }
 
         if (pfrom->nVersion >= SENDHEADERS_VERSION) {
             // Tell our peer we prefer to receive headers rather than inv's
             // We send this to non-NODE NETWORK peers as well, because even
             // non-NODE NETWORK peers can announce blocks (such as pruning
             // nodes)
             connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::SENDHEADERS));
         }
         if (pfrom->nVersion >= SHORT_IDS_BLOCKS_VERSION) {
             // Tell our peer we are willing to provide version 1 or 2
             // cmpctblocks. However, we do not request new block announcements
             // using cmpctblock messages. We send this to non-NODE NETWORK peers
             // as well, because they may wish to request compact blocks from us.
             bool fAnnounceUsingCMPCTBLOCK = false;
             uint64_t nCMPCTBLOCKVersion = 1;
             connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::SENDCMPCT,
                                                      fAnnounceUsingCMPCTBLOCK,
                                                      nCMPCTBLOCKVersion));
         }
         pfrom->fSuccessfullyConnected = true;
     }
 
     else if (!pfrom->fSuccessfullyConnected) {
         // Must have a verack message before anything else
         LOCK(cs_main);
         Misbehaving(pfrom->GetId(), 1);
         return false;
     }
 
     else if (strCommand == NetMsgType::ADDR) {
         std::vector<CAddress> vAddr;
         vRecv >> vAddr;
 
         // Don't want addr from older versions unless seeding
         if (pfrom->nVersion < CADDR_TIME_VERSION &&
             connman.GetAddressCount() > 1000)
             return true;
         if (vAddr.size() > 1000) {
             LOCK(cs_main);
             Misbehaving(pfrom->GetId(), 20);
             return error("message addr size() = %u", vAddr.size());
         }
 
         // Store the new addresses
         std::vector<CAddress> vAddrOk;
         int64_t nNow = GetAdjustedTime();
         int64_t nSince = nNow - 10 * 60;
         for (CAddress &addr : vAddr) {
             if (interruptMsgProc) return true;
 
             if ((addr.nServices & REQUIRED_SERVICES) != REQUIRED_SERVICES)
                 continue;
 
             if (addr.nTime <= 100000000 || addr.nTime > nNow + 10 * 60)
                 addr.nTime = nNow - 5 * 24 * 60 * 60;
             pfrom->AddAddressKnown(addr);
             bool fReachable = IsReachable(addr);
             if (addr.nTime > nSince && !pfrom->fGetAddr && vAddr.size() <= 10 &&
                 addr.IsRoutable()) {
                 // Relay to a limited number of other nodes
                 RelayAddress(addr, fReachable, connman);
             }
             // Do not store addresses outside our network
             if (fReachable) vAddrOk.push_back(addr);
         }
         connman.AddNewAddresses(vAddrOk, pfrom->addr, 2 * 60 * 60);
         if (vAddr.size() < 1000) pfrom->fGetAddr = false;
         if (pfrom->fOneShot) pfrom->fDisconnect = true;
     }
 
     else if (strCommand == NetMsgType::SENDHEADERS) {
         LOCK(cs_main);
         State(pfrom->GetId())->fPreferHeaders = true;
     }
 
     else if (strCommand == NetMsgType::SENDCMPCT) {
         bool fAnnounceUsingCMPCTBLOCK = false;
         uint64_t nCMPCTBLOCKVersion = 0;
         vRecv >> fAnnounceUsingCMPCTBLOCK >> nCMPCTBLOCKVersion;
         if (nCMPCTBLOCKVersion == 1) {
             LOCK(cs_main);
             // fProvidesHeaderAndIDs is used to "lock in" version of compact
             // blocks we send.
             if (!State(pfrom->GetId())->fProvidesHeaderAndIDs) {
                 State(pfrom->GetId())->fProvidesHeaderAndIDs = true;
             }
 
             State(pfrom->GetId())->fPreferHeaderAndIDs =
                 fAnnounceUsingCMPCTBLOCK;
             if (!State(pfrom->GetId())->fSupportsDesiredCmpctVersion) {
                 State(pfrom->GetId())->fSupportsDesiredCmpctVersion = true;
             }
         }
     }
 
     else if (strCommand == NetMsgType::INV) {
         std::vector<CInv> vInv;
         vRecv >> vInv;
         if (vInv.size() > MAX_INV_SZ) {
             LOCK(cs_main);
             Misbehaving(pfrom->GetId(), 20);
             return error("message inv size() = %u", vInv.size());
         }
 
         bool fBlocksOnly = !fRelayTxes;
 
         // Allow whitelisted peers to send data other than blocks in blocks only
         // mode if whitelistrelay is true
         if (pfrom->fWhitelisted &&
             GetBoolArg("-whitelistrelay", DEFAULT_WHITELISTRELAY))
             fBlocksOnly = false;
 
         LOCK(cs_main);
 
         uint32_t nFetchFlags =
             GetFetchFlags(pfrom, chainActive.Tip(), chainparams.GetConsensus());
 
         std::vector<CInv> vToFetch;
 
         for (unsigned int nInv = 0; nInv < vInv.size(); nInv++) {
             CInv &inv = vInv[nInv];
 
             if (interruptMsgProc) return true;
 
             bool fAlreadyHave = AlreadyHave(inv);
             LogPrint("net", "got inv: %s  %s peer=%d\n", inv.ToString(),
                      fAlreadyHave ? "have" : "new", pfrom->id);
 
             if (inv.type == MSG_TX) {
                 inv.type |= nFetchFlags;
             }
 
             if (inv.type == MSG_BLOCK) {
                 UpdateBlockAvailability(pfrom->GetId(), inv.hash);
                 if (!fAlreadyHave && !fImporting && !fReindex &&
                     !mapBlocksInFlight.count(inv.hash)) {
                     // We used to request the full block here, but since
                     // headers-announcements are now the primary method of
                     // announcement on the network, and since, in the case that
                     // a node fell back to inv we probably have a reorg which we
                     // should get the headers for first, we now only provide a
                     // getheaders response here. When we receive the headers, we
                     // will then ask for the blocks we need.
                     connman.PushMessage(
                         pfrom,
                         msgMaker.Make(NetMsgType::GETHEADERS,
                                       chainActive.GetLocator(pindexBestHeader),
                                       inv.hash));
                     LogPrint("net", "getheaders (%d) %s to peer=%d\n",
                              pindexBestHeader->nHeight, inv.hash.ToString(),
                              pfrom->id);
                 }
             } else {
                 pfrom->AddInventoryKnown(inv);
                 if (fBlocksOnly)
                     LogPrint("net", "transaction (%s) inv sent in violation of "
                                     "protocol peer=%d\n",
                              inv.hash.ToString(), pfrom->id);
                 else if (!fAlreadyHave && !fImporting && !fReindex &&
                          !IsInitialBlockDownload())
                     pfrom->AskFor(inv);
             }
 
             // Track requests for our stuff
             GetMainSignals().Inventory(inv.hash);
         }
 
         if (!vToFetch.empty())
             connman.PushMessage(pfrom,
                                 msgMaker.Make(NetMsgType::GETDATA, vToFetch));
     }
 
     else if (strCommand == NetMsgType::GETDATA) {
         std::vector<CInv> vInv;
         vRecv >> vInv;
         if (vInv.size() > MAX_INV_SZ) {
             LOCK(cs_main);
             Misbehaving(pfrom->GetId(), 20);
             return error("message getdata size() = %u", vInv.size());
         }
 
         if (fDebug || (vInv.size() != 1))
             LogPrint("net", "received getdata (%u invsz) peer=%d\n",
                      vInv.size(), pfrom->id);
 
         if ((fDebug && vInv.size() > 0) || (vInv.size() == 1))
             LogPrint("net", "received getdata for: %s peer=%d\n",
                      vInv[0].ToString(), pfrom->id);
 
         pfrom->vRecvGetData.insert(pfrom->vRecvGetData.end(), vInv.begin(),
                                    vInv.end());
         ProcessGetData(config, pfrom, chainparams.GetConsensus(), connman,
                        interruptMsgProc);
     }
 
     else if (strCommand == NetMsgType::GETBLOCKS) {
         CBlockLocator locator;
         uint256 hashStop;
         vRecv >> locator >> hashStop;
 
         // We might have announced the currently-being-connected tip using a
         // compact block, which resulted in the peer sending a getblocks
         // request, which we would otherwise respond to without the new block.
         // To avoid this situation we simply verify that we are on our best
         // known chain now. This is super overkill, but we handle it better
         // for getheaders requests, and there are no known nodes which support
         // compact blocks but still use getblocks to request blocks.
         {
             std::shared_ptr<const CBlock> a_recent_block;
             {
                 LOCK(cs_most_recent_block);
                 a_recent_block = most_recent_block;
             }
             CValidationState dummy;
             ActivateBestChain(config, dummy, a_recent_block);
         }
 
         LOCK(cs_main);
 
         // Find the last block the caller has in the main chain
         const CBlockIndex *pindex = FindForkInGlobalIndex(chainActive, locator);
 
         // Send the rest of the chain
         if (pindex) pindex = chainActive.Next(pindex);
         int nLimit = 500;
         LogPrint("net", "getblocks %d to %s limit %d from peer=%d\n",
                  (pindex ? pindex->nHeight : -1),
                  hashStop.IsNull() ? "end" : hashStop.ToString(), nLimit,
                  pfrom->id);
         for (; pindex; pindex = chainActive.Next(pindex)) {
             if (pindex->GetBlockHash() == hashStop) {
                 LogPrint("net", "  getblocks stopping at %d %s\n",
                          pindex->nHeight, pindex->GetBlockHash().ToString());
                 break;
             }
             // If pruning, don't inv blocks unless we have on disk and are
             // likely to still have for some reasonable time window (1 hour)
             // that block relay might require.
             const int nPrunedBlocksLikelyToHave =
                 MIN_BLOCKS_TO_KEEP -
                 3600 / chainparams.GetConsensus().nPowTargetSpacing;
             if (fPruneMode &&
                 (!(pindex->nStatus & BLOCK_HAVE_DATA) ||
                  pindex->nHeight <=
                      chainActive.Tip()->nHeight - nPrunedBlocksLikelyToHave)) {
                 LogPrint(
                     "net",
                     " getblocks stopping, pruned or too old block at %d %s\n",
                     pindex->nHeight, pindex->GetBlockHash().ToString());
                 break;
             }
             pfrom->PushInventory(CInv(MSG_BLOCK, pindex->GetBlockHash()));
             if (--nLimit <= 0) {
                 // When this block is requested, we'll send an inv that'll
                 // trigger the peer to getblocks the next batch of inventory.
                 LogPrint("net", "  getblocks stopping at limit %d %s\n",
                          pindex->nHeight, pindex->GetBlockHash().ToString());
                 pfrom->hashContinue = pindex->GetBlockHash();
                 break;
             }
         }
     }
 
     else if (strCommand == NetMsgType::GETBLOCKTXN) {
         BlockTransactionsRequest req;
         vRecv >> req;
 
         std::shared_ptr<const CBlock> recent_block;
         {
             LOCK(cs_most_recent_block);
             if (most_recent_block_hash == req.blockhash)
                 recent_block = most_recent_block;
             // Unlock cs_most_recent_block to avoid cs_main lock inversion
         }
         if (recent_block) {
             SendBlockTransactions(*recent_block, req, pfrom, connman);
             return true;
         }
 
         LOCK(cs_main);
 
         BlockMap::iterator it = mapBlockIndex.find(req.blockhash);
         if (it == mapBlockIndex.end() ||
             !(it->second->nStatus & BLOCK_HAVE_DATA)) {
             LogPrintf("Peer %d sent us a getblocktxn for a block we don't have",
                       pfrom->id);
             return true;
         }
 
         if (it->second->nHeight < chainActive.Height() - MAX_BLOCKTXN_DEPTH) {
             // If an older block is requested (should never happen in practice,
             // but can happen in tests) send a block response instead of a
             // blocktxn response. Sending a full block response instead of a
             // small blocktxn response is preferable in the case where a peer
             // might maliciously send lots of getblocktxn requests to trigger
             // expensive disk reads, because it will require the peer to
             // actually receive all the data read from disk over the network.
             LogPrint("net",
                      "Peer %d sent us a getblocktxn for a block > %i deep",
                      pfrom->id, MAX_BLOCKTXN_DEPTH);
             CInv inv;
             inv.type = MSG_BLOCK;
             inv.hash = req.blockhash;
             pfrom->vRecvGetData.push_back(inv);
             ProcessGetData(config, pfrom, chainparams.GetConsensus(), connman,
                            interruptMsgProc);
             return true;
         }
 
         CBlock block;
         bool ret =
             ReadBlockFromDisk(block, it->second, chainparams.GetConsensus());
         assert(ret);
 
         SendBlockTransactions(block, req, pfrom, connman);
     }
 
     else if (strCommand == NetMsgType::GETHEADERS) {
         CBlockLocator locator;
         uint256 hashStop;
         vRecv >> locator >> hashStop;
 
         LOCK(cs_main);
         if (IsInitialBlockDownload() && !pfrom->fWhitelisted) {
             LogPrint("net", "Ignoring getheaders from peer=%d because node is "
                             "in initial block download\n",
                      pfrom->id);
             return true;
         }
 
         CNodeState *nodestate = State(pfrom->GetId());
         const CBlockIndex *pindex = nullptr;
         if (locator.IsNull()) {
             // If locator is null, return the hashStop block
             BlockMap::iterator mi = mapBlockIndex.find(hashStop);
             if (mi == mapBlockIndex.end()) return true;
             pindex = (*mi).second;
         } else {
             // Find the last block the caller has in the main chain
             pindex = FindForkInGlobalIndex(chainActive, locator);
             if (pindex) pindex = chainActive.Next(pindex);
         }
 
         // we must use CBlocks, as CBlockHeaders won't include the 0x00 nTx
         // count at the end
         std::vector<CBlock> vHeaders;
         int nLimit = MAX_HEADERS_RESULTS;
         LogPrint("net", "getheaders %d to %s from peer=%d\n",
                  (pindex ? pindex->nHeight : -1),
                  hashStop.IsNull() ? "end" : hashStop.ToString(), pfrom->id);
         for (; pindex; pindex = chainActive.Next(pindex)) {
             vHeaders.push_back(pindex->GetBlockHeader());
             if (--nLimit <= 0 || pindex->GetBlockHash() == hashStop) break;
         }
         // pindex can be nullptr either if we sent chainActive.Tip() OR
         // if our peer has chainActive.Tip() (and thus we are sending an empty
         // headers message). In both cases it's safe to update
         // pindexBestHeaderSent to be our tip.
         //
         // It is important that we simply reset the BestHeaderSent value here,
         // and not max(BestHeaderSent, newHeaderSent). We might have announced
         // the currently-being-connected tip using a compact block, which
         // resulted in the peer sending a headers request, which we respond to
         // without the new block. By resetting the BestHeaderSent, we ensure we
         // will re-announce the new block via headers (or compact blocks again)
         // in the SendMessages logic.
         nodestate->pindexBestHeaderSent = pindex ? pindex : chainActive.Tip();
         connman.PushMessage(pfrom,
                             msgMaker.Make(NetMsgType::HEADERS, vHeaders));
     }
 
     else if (strCommand == NetMsgType::TX) {
         // Stop processing the transaction early if
         // We are in blocks only mode and peer is either not whitelisted or
         // whitelistrelay is off
         if (!fRelayTxes &&
             (!pfrom->fWhitelisted ||
              !GetBoolArg("-whitelistrelay", DEFAULT_WHITELISTRELAY))) {
             LogPrint("net",
                      "transaction sent in violation of protocol peer=%d\n",
                      pfrom->id);
             return true;
         }
 
         std::deque<COutPoint> vWorkQueue;
         std::vector<uint256> vEraseQueue;
         CTransactionRef ptx;
         vRecv >> ptx;
         const CTransaction &tx = *ptx;
 
         CInv inv(MSG_TX, tx.GetId());
         pfrom->AddInventoryKnown(inv);
 
         LOCK(cs_main);
 
         bool fMissingInputs = false;
         CValidationState state;
 
         pfrom->setAskFor.erase(inv.hash);
         mapAlreadyAskedFor.erase(inv.hash);
 
         std::list<CTransactionRef> lRemovedTxn;
 
         if (!AlreadyHave(inv) &&
             AcceptToMemoryPool(config, mempool, state, ptx, true,
                                &fMissingInputs, &lRemovedTxn)) {
             mempool.check(pcoinsTip);
             RelayTransaction(tx, connman);
             for (unsigned int i = 0; i < tx.vout.size(); i++) {
                 vWorkQueue.emplace_back(inv.hash, i);
             }
 
             pfrom->nLastTXTime = GetTime();
 
             LogPrint("mempool", "AcceptToMemoryPool: peer=%d: accepted %s "
                                 "(poolsz %u txn, %u kB)\n",
                      pfrom->id, tx.GetId().ToString(), mempool.size(),
                      mempool.DynamicMemoryUsage() / 1000);
 
             // Recursively process any orphan transactions that depended on this
             // one
             std::set<NodeId> setMisbehaving;
             while (!vWorkQueue.empty()) {
                 auto itByPrev =
                     mapOrphanTransactionsByPrev.find(vWorkQueue.front());
                 vWorkQueue.pop_front();
                 if (itByPrev == mapOrphanTransactionsByPrev.end()) continue;
                 for (auto mi = itByPrev->second.begin();
                      mi != itByPrev->second.end(); ++mi) {
                     const CTransactionRef &porphanTx = (*mi)->second.tx;
                     const CTransaction &orphanTx = *porphanTx;
                     const uint256 &orphanId = orphanTx.GetId();
                     NodeId fromPeer = (*mi)->second.fromPeer;
                     bool fMissingInputs2 = false;
                     // Use a dummy CValidationState so someone can't setup nodes
                     // to counter-DoS based on orphan resolution (that is,
                     // feeding people an invalid transaction based on LegitTxX
                     // in order to get anyone relaying LegitTxX banned)
                     CValidationState stateDummy;
 
                     if (setMisbehaving.count(fromPeer)) continue;
                     if (AcceptToMemoryPool(config, mempool, stateDummy,
                                            porphanTx, true, &fMissingInputs2,
                                            &lRemovedTxn)) {
                         LogPrint("mempool", "   accepted orphan tx %s\n",
                                  orphanId.ToString());
                         RelayTransaction(orphanTx, connman);
                         for (unsigned int i = 0; i < orphanTx.vout.size();
                              i++) {
                             vWorkQueue.emplace_back(orphanId, i);
                         }
                         vEraseQueue.push_back(orphanId);
                     } else if (!fMissingInputs2) {
                         int nDos = 0;
                         if (stateDummy.IsInvalid(nDos) && nDos > 0) {
                             // Punish peer that gave us an invalid orphan tx
                             Misbehaving(fromPeer, nDos);
                             setMisbehaving.insert(fromPeer);
                             LogPrint("mempool", "   invalid orphan tx %s\n",
                                      orphanId.ToString());
                         }
                         // Has inputs but not accepted to mempool
                         // Probably non-standard or insufficient fee/priority
                         LogPrint("mempool", "   removed orphan tx %s\n",
                                  orphanId.ToString());
                         vEraseQueue.push_back(orphanId);
                         if (!stateDummy.CorruptionPossible()) {
                             // Do not use rejection cache for witness
                             // transactions or witness-stripped transactions, as
                             // they can have been malleated. See
                             // https://github.com/bitcoin/bitcoin/issues/8279
                             // for details.
                             assert(recentRejects);
                             recentRejects->insert(orphanId);
                         }
                     }
                     mempool.check(pcoinsTip);
                 }
             }
 
             for (uint256 hash : vEraseQueue) {
                 EraseOrphanTx(hash);
             }
         } else if (fMissingInputs) {
             // It may be the case that the orphans parents have all been
             // rejected.
             bool fRejectedParents = false;
             for (const CTxIn &txin : tx.vin) {
                 if (recentRejects->contains(txin.prevout.hash)) {
                     fRejectedParents = true;
                     break;
                 }
             }
             if (!fRejectedParents) {
                 uint32_t nFetchFlags = GetFetchFlags(
                     pfrom, chainActive.Tip(), chainparams.GetConsensus());
                 for (const CTxIn &txin : tx.vin) {
                     CInv _inv(MSG_TX | nFetchFlags, txin.prevout.hash);
                     pfrom->AddInventoryKnown(_inv);
                     if (!AlreadyHave(_inv)) pfrom->AskFor(_inv);
                 }
                 AddOrphanTx(ptx, pfrom->GetId());
 
                 // DoS prevention: do not allow mapOrphanTransactions to grow
                 // unbounded
                 unsigned int nMaxOrphanTx = (unsigned int)std::max(
                     (int64_t)0,
                     GetArg("-maxorphantx", DEFAULT_MAX_ORPHAN_TRANSACTIONS));
                 unsigned int nEvicted = LimitOrphanTxSize(nMaxOrphanTx);
                 if (nEvicted > 0)
                     LogPrint("mempool", "mapOrphan overflow, removed %u tx\n",
                              nEvicted);
             } else {
                 LogPrint("mempool",
                          "not keeping orphan with rejected parents %s\n",
                          tx.GetId().ToString());
                 // We will continue to reject this tx since it has rejected
                 // parents so avoid re-requesting it from other peers.
                 recentRejects->insert(tx.GetId());
             }
         } else {
             if (!state.CorruptionPossible()) {
                 // Do not use rejection cache for witness transactions or
                 // witness-stripped transactions, as they can have been
                 // malleated. See https://github.com/bitcoin/bitcoin/issues/8279
                 // for details.
                 assert(recentRejects);
                 recentRejects->insert(tx.GetId());
                 if (RecursiveDynamicUsage(*ptx) < 100000) {
                     AddToCompactExtraTransactions(ptx);
                 }
             }
 
             if (pfrom->fWhitelisted &&
                 GetBoolArg("-whitelistforcerelay",
                            DEFAULT_WHITELISTFORCERELAY)) {
                 // Always relay transactions received from whitelisted peers,
                 // even if they were already in the mempool or rejected from it
                 // due to policy, allowing the node to function as a gateway for
                 // nodes hidden behind it.
                 //
                 // Never relay transactions that we would assign a non-zero DoS
                 // score for, as we expect peers to do the same with us in that
                 // case.
                 int nDoS = 0;
                 if (!state.IsInvalid(nDoS) || nDoS == 0) {
                     LogPrintf("Force relaying tx %s from whitelisted peer=%d\n",
                               tx.GetId().ToString(), pfrom->id);
                     RelayTransaction(tx, connman);
                 } else {
                     LogPrintf("Not relaying invalid transaction %s from "
                               "whitelisted peer=%d (%s)\n",
                               tx.GetId().ToString(), pfrom->id,
                               FormatStateMessage(state));
                 }
             }
         }
 
         for (const CTransactionRef &removedTx : lRemovedTxn)
             AddToCompactExtraTransactions(removedTx);
 
         int nDoS = 0;
         if (state.IsInvalid(nDoS)) {
             LogPrint("mempoolrej", "%s from peer=%d was not accepted: %s\n",
                      tx.GetId().ToString(), pfrom->id,
                      FormatStateMessage(state));
             // Never send AcceptToMemoryPool's internal codes over P2P.
             if (state.GetRejectCode() < REJECT_INTERNAL)
                 connman.PushMessage(
                     pfrom, msgMaker.Make(NetMsgType::REJECT, strCommand,
                                          (unsigned char)state.GetRejectCode(),
                                          state.GetRejectReason().substr(
                                              0, MAX_REJECT_MESSAGE_LENGTH),
                                          inv.hash));
             if (nDoS > 0) {
                 Misbehaving(pfrom->GetId(), nDoS);
             }
         }
     }
 
     else if (strCommand == NetMsgType::CMPCTBLOCK && !fImporting &&
              !fReindex) // Ignore blocks received while importing
     {
         CBlockHeaderAndShortTxIDs cmpctblock;
         vRecv >> cmpctblock;
 
         {
             LOCK(cs_main);
 
             if (mapBlockIndex.find(cmpctblock.header.hashPrevBlock) ==
                 mapBlockIndex.end()) {
                 // Doesn't connect (or is genesis), instead of DoSing in
                 // AcceptBlockHeader, request deeper headers
                 if (!IsInitialBlockDownload())
                     connman.PushMessage(
                         pfrom,
                         msgMaker.Make(NetMsgType::GETHEADERS,
                                       chainActive.GetLocator(pindexBestHeader),
                                       uint256()));
                 return true;
             }
         }
 
         const CBlockIndex *pindex = nullptr;
         CValidationState state;
         if (!ProcessNewBlockHeaders(config, {cmpctblock.header}, state,
                                     &pindex)) {
             int nDoS;
             if (state.IsInvalid(nDoS)) {
                 if (nDoS > 0) {
                     LOCK(cs_main);
                     Misbehaving(pfrom->GetId(), nDoS);
                 }
                 LogPrintf("Peer %d sent us invalid header via cmpctblock\n",
                           pfrom->id);
                 return true;
             }
         }
 
         // When we succeed in decoding a block's txids from a cmpctblock
         // message we typically jump to the BLOCKTXN handling code, with a
         // dummy (empty) BLOCKTXN message, to re-use the logic there in
         // completing processing of the putative block (without cs_main).
         bool fProcessBLOCKTXN = false;
         CDataStream blockTxnMsg(SER_NETWORK, PROTOCOL_VERSION);
 
         // If we end up treating this as a plain headers message, call that as
         // well
         // without cs_main.
         bool fRevertToHeaderProcessing = false;
         CDataStream vHeadersMsg(SER_NETWORK, PROTOCOL_VERSION);
 
         // Keep a CBlock for "optimistic" compactblock reconstructions (see
         // below)
         std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
         bool fBlockReconstructed = false;
 
         {
             LOCK(cs_main);
             // If AcceptBlockHeader returned true, it set pindex
             assert(pindex);
             UpdateBlockAvailability(pfrom->GetId(), pindex->GetBlockHash());
 
             std::map<uint256,
                      std::pair<NodeId, std::list<QueuedBlock>::iterator>>::
                 iterator blockInFlightIt =
                     mapBlocksInFlight.find(pindex->GetBlockHash());
             bool fAlreadyInFlight = blockInFlightIt != mapBlocksInFlight.end();
 
             if (pindex->nStatus & BLOCK_HAVE_DATA) // Nothing to do here
                 return true;
 
             if (pindex->nChainWork <=
                     chainActive.Tip()->nChainWork || // We know something better
                 pindex->nTx !=
                     0) { // We had this block at some point, but pruned it
                 if (fAlreadyInFlight) {
                     // We requested this block for some reason, but our mempool
                     // will probably be useless so we just grab the block via
                     // normal getdata.
                     std::vector<CInv> vInv(1);
                     vInv[0] = CInv(
                         MSG_BLOCK | GetFetchFlags(pfrom, pindex->pprev,
                                                   chainparams.GetConsensus()),
                         cmpctblock.header.GetHash());
                     connman.PushMessage(
                         pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv));
                 }
                 return true;
             }
 
             // If we're not close to tip yet, give up and let parallel block
             // fetch work its magic.
             if (!fAlreadyInFlight &&
                 !CanDirectFetch(chainparams.GetConsensus()))
                 return true;
 
             CNodeState *nodestate = State(pfrom->GetId());
 
             // We want to be a bit conservative just to be extra careful about
             // DoS possibilities in compact block processing...
             if (pindex->nHeight <= chainActive.Height() + 2) {
                 if ((!fAlreadyInFlight &&
                      nodestate->nBlocksInFlight <
                          MAX_BLOCKS_IN_TRANSIT_PER_PEER) ||
                     (fAlreadyInFlight &&
                      blockInFlightIt->second.first == pfrom->GetId())) {
                     std::list<QueuedBlock>::iterator *queuedBlockIt = nullptr;
                     if (!MarkBlockAsInFlight(config, pfrom->GetId(),
                                              pindex->GetBlockHash(),
                                              chainparams.GetConsensus(), pindex,
                                              &queuedBlockIt)) {
                         if (!(*queuedBlockIt)->partialBlock)
                             (*queuedBlockIt)
                                 ->partialBlock.reset(
                                     new PartiallyDownloadedBlock(config,
                                                                  &mempool));
                         else {
                             // The block was already in flight using compact
                             // blocks from the same peer.
                             LogPrint("net", "Peer sent us compact block we "
                                             "were already syncing!\n");
                             return true;
                         }
                     }
 
                     PartiallyDownloadedBlock &partialBlock =
                         *(*queuedBlockIt)->partialBlock;
                     ReadStatus status =
                         partialBlock.InitData(cmpctblock, vExtraTxnForCompact);
                     if (status == READ_STATUS_INVALID) {
                         MarkBlockAsReceived(
                             pindex->GetBlockHash()); // Reset in-flight state in
                                                      // case of whitelist
                         Misbehaving(pfrom->GetId(), 100);
                         LogPrintf("Peer %d sent us invalid compact block\n",
                                   pfrom->id);
                         return true;
                     } else if (status == READ_STATUS_FAILED) {
                         // Duplicate txindexes, the block is now in-flight, so
                         // just request it.
                         std::vector<CInv> vInv(1);
                         vInv[0] =
                             CInv(MSG_BLOCK |
                                      GetFetchFlags(pfrom, pindex->pprev,
                                                    chainparams.GetConsensus()),
                                  cmpctblock.header.GetHash());
                         connman.PushMessage(
                             pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv));
                         return true;
                     }
 
                     BlockTransactionsRequest req;
                     for (size_t i = 0; i < cmpctblock.BlockTxCount(); i++) {
                         if (!partialBlock.IsTxAvailable(i))
                             req.indexes.push_back(i);
                     }
                     if (req.indexes.empty()) {
                         // Dirty hack to jump to BLOCKTXN code (TODO: move
                         // message handling into their own functions)
                         BlockTransactions txn;
                         txn.blockhash = cmpctblock.header.GetHash();
                         blockTxnMsg << txn;
                         fProcessBLOCKTXN = true;
                     } else {
                         req.blockhash = pindex->GetBlockHash();
                         connman.PushMessage(
                             pfrom, msgMaker.Make(NetMsgType::GETBLOCKTXN, req));
                     }
                 } else {
                     // This block is either already in flight from a different
                     // peer, or this peer has too many blocks outstanding to
                     // download from. Optimistically try to reconstruct anyway
                     // since we might be able to without any round trips.
                     PartiallyDownloadedBlock tempBlock(config, &mempool);
                     ReadStatus status =
                         tempBlock.InitData(cmpctblock, vExtraTxnForCompact);
                     if (status != READ_STATUS_OK) {
                         // TODO: don't ignore failures
                         return true;
                     }
                     std::vector<CTransactionRef> dummy;
                     status = tempBlock.FillBlock(*pblock, dummy);
                     if (status == READ_STATUS_OK) {
                         fBlockReconstructed = true;
                     }
                 }
             } else {
                 if (fAlreadyInFlight) {
                     // We requested this block, but its far into the future, so
                     // our mempool will probably be useless - request the block
                     // normally.
                     std::vector<CInv> vInv(1);
                     vInv[0] = CInv(
                         MSG_BLOCK | GetFetchFlags(pfrom, pindex->pprev,
                                                   chainparams.GetConsensus()),
                         cmpctblock.header.GetHash());
                     connman.PushMessage(
                         pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv));
                     return true;
                 } else {
                     // If this was an announce-cmpctblock, we want the same
                     // treatment as a header message. Dirty hack to process as
                     // if it were just a headers message (TODO: move message
                     // handling into their own functions)
                     std::vector<CBlock> headers;
                     headers.push_back(cmpctblock.header);
                     vHeadersMsg << headers;
                     fRevertToHeaderProcessing = true;
                 }
             }
         } // cs_main
 
         if (fProcessBLOCKTXN)
             return ProcessMessage(config, pfrom, NetMsgType::BLOCKTXN,
                                   blockTxnMsg, nTimeReceived, chainparams,
                                   connman, interruptMsgProc);
 
         if (fRevertToHeaderProcessing)
             return ProcessMessage(config, pfrom, NetMsgType::HEADERS,
                                   vHeadersMsg, nTimeReceived, chainparams,
                                   connman, interruptMsgProc);
 
         if (fBlockReconstructed) {
             // If we got here, we were able to optimistically reconstruct a
             // block that is in flight from some other peer.
             {
                 LOCK(cs_main);
                 mapBlockSource.emplace(pblock->GetHash(),
                                        std::make_pair(pfrom->GetId(), false));
             }
             bool fNewBlock = false;
             ProcessNewBlock(config, pblock, true, &fNewBlock);
             if (fNewBlock) pfrom->nLastBlockTime = GetTime();
 
             LOCK(cs_main); // hold cs_main for CBlockIndex::IsValid()
             if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS)) {
                 // Clear download state for this block, which is in process from
                 // some other peer. We do this after calling. ProcessNewBlock so
                 // that a malleated cmpctblock announcement can't be used to
                 // interfere with block relay.
                 MarkBlockAsReceived(pblock->GetHash());
             }
         }
 
     }
 
     else if (strCommand == NetMsgType::BLOCKTXN && !fImporting &&
              !fReindex) // Ignore blocks received while importing
     {
         BlockTransactions resp;
         vRecv >> resp;
 
         std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
         bool fBlockRead = false;
         {
             LOCK(cs_main);
 
             std::map<uint256,
                      std::pair<NodeId,
                                std::list<QueuedBlock>::iterator>>::iterator it =
                 mapBlocksInFlight.find(resp.blockhash);
             if (it == mapBlocksInFlight.end() ||
                 !it->second.second->partialBlock ||
                 it->second.first != pfrom->GetId()) {
                 LogPrint("net", "Peer %d sent us block transactions for block "
                                 "we weren't expecting\n",
                          pfrom->id);
                 return true;
             }
 
             PartiallyDownloadedBlock &partialBlock =
                 *it->second.second->partialBlock;
             ReadStatus status = partialBlock.FillBlock(*pblock, resp.txn);
             if (status == READ_STATUS_INVALID) {
                 // Reset in-flight state in case of whitelist.
                 MarkBlockAsReceived(resp.blockhash);
                 Misbehaving(pfrom->GetId(), 100);
                 LogPrintf("Peer %d sent us invalid compact block/non-matching "
                           "block transactions\n",
                           pfrom->id);
                 return true;
             } else if (status == READ_STATUS_FAILED) {
                 // Might have collided, fall back to getdata now :(
                 std::vector<CInv> invs;
                 invs.push_back(
                     CInv(MSG_BLOCK | GetFetchFlags(pfrom, chainActive.Tip(),
                                                    chainparams.GetConsensus()),
                          resp.blockhash));
                 connman.PushMessage(pfrom,
                                     msgMaker.Make(NetMsgType::GETDATA, invs));
             } else {
                 // Block is either okay, or possibly we received
                 // READ_STATUS_CHECKBLOCK_FAILED.
                 // Note that CheckBlock can only fail for one of a few reasons:
                 // 1. bad-proof-of-work (impossible here, because we've already
                 //    accepted the header)
                 // 2. merkleroot doesn't match the transactions given (already
                 //    caught in FillBlock with READ_STATUS_FAILED, so
                 //    impossible here)
                 // 3. the block is otherwise invalid (eg invalid coinbase,
                 //    block is too big, too many legacy sigops, etc).
                 // So if CheckBlock failed, #3 is the only possibility.
                 // Under BIP 152, we don't DoS-ban unless proof of work is
                 // invalid (we don't require all the stateless checks to have
                 // been run). This is handled below, so just treat this as
                 // though the block was successfully read, and rely on the
                 // handling in ProcessNewBlock to ensure the block index is
                 // updated, reject messages go out, etc.
 
                 // it is now an empty pointer
                 MarkBlockAsReceived(resp.blockhash);
                 fBlockRead = true;
                 // mapBlockSource is only used for sending reject messages and
                 // DoS scores, so the race between here and cs_main in
                 // ProcessNewBlock is fine. BIP 152 permits peers to relay
                 // compact blocks after validating the header only; we should
                 // not punish peers if the block turns out to be invalid.
                 mapBlockSource.emplace(resp.blockhash,
                                        std::make_pair(pfrom->GetId(), false));
             }
         } // Don't hold cs_main when we call into ProcessNewBlock
         if (fBlockRead) {
             bool fNewBlock = false;
             // Since we requested this block (it was in mapBlocksInFlight),
             // force it to be processed, even if it would not be a candidate for
             // new tip (missing previous block, chain not long enough, etc)
             ProcessNewBlock(config, pblock, true, &fNewBlock);
             if (fNewBlock) pfrom->nLastBlockTime = GetTime();
         }
     }
 
     else if (strCommand == NetMsgType::HEADERS && !fImporting &&
              !fReindex) // Ignore headers received while importing
     {
         std::vector<CBlockHeader> headers;
 
         // Bypass the normal CBlock deserialization, as we don't want to risk
         // deserializing 2000 full blocks.
         unsigned int nCount = ReadCompactSize(vRecv);
         if (nCount > MAX_HEADERS_RESULTS) {
             LOCK(cs_main);
             Misbehaving(pfrom->GetId(), 20);
             return error("headers message size = %u", nCount);
         }
         headers.resize(nCount);
         for (unsigned int n = 0; n < nCount; n++) {
             vRecv >> headers[n];
             // ignore tx count; assume it is 0.
             ReadCompactSize(vRecv);
         }
 
         if (nCount == 0) {
             // Nothing interesting. Stop asking this peers for more headers.
             return true;
         }
 
         const CBlockIndex *pindexLast = nullptr;
         {
             LOCK(cs_main);
             CNodeState *nodestate = State(pfrom->GetId());
 
             // If this looks like it could be a block announcement (nCount <
             // MAX_BLOCKS_TO_ANNOUNCE), use special logic for handling headers
             // that
             // don't connect:
             // - Send a getheaders message in response to try to connect the
             // chain.
             // - The peer can send up to MAX_UNCONNECTING_HEADERS in a row that
             //   don't connect before giving DoS points
             // - Once a headers message is received that is valid and does
             // connect,
             //   nUnconnectingHeaders gets reset back to 0.
             if (mapBlockIndex.find(headers[0].hashPrevBlock) ==
                     mapBlockIndex.end() &&
                 nCount < MAX_BLOCKS_TO_ANNOUNCE) {
                 nodestate->nUnconnectingHeaders++;
                 connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::GETHEADERS,
                                                          chainActive.GetLocator(
                                                              pindexBestHeader),
                                                          uint256()));
                 LogPrint("net", "received header %s: missing prev block %s, "
                                 "sending getheaders (%d) to end (peer=%d, "
                                 "nUnconnectingHeaders=%d)\n",
                          headers[0].GetHash().ToString(),
                          headers[0].hashPrevBlock.ToString(),
                          pindexBestHeader->nHeight, pfrom->id,
                          nodestate->nUnconnectingHeaders);
                 // Set hashLastUnknownBlock for this peer, so that if we
                 // eventually get the headers - even from a different peer -
                 // we can use this peer to download.
                 UpdateBlockAvailability(pfrom->GetId(),
                                         headers.back().GetHash());
 
                 if (nodestate->nUnconnectingHeaders %
                         MAX_UNCONNECTING_HEADERS ==
                     0) {
                     Misbehaving(pfrom->GetId(), 20);
                 }
                 return true;
             }
 
             uint256 hashLastBlock;
             for (const CBlockHeader &header : headers) {
                 if (!hashLastBlock.IsNull() &&
                     header.hashPrevBlock != hashLastBlock) {
                     Misbehaving(pfrom->GetId(), 20);
                     return error("non-continuous headers sequence");
                 }
                 hashLastBlock = header.GetHash();
             }
         }
 
         CValidationState state;
         if (!ProcessNewBlockHeaders(config, headers, state, &pindexLast)) {
             int nDoS;
             if (state.IsInvalid(nDoS)) {
                 if (nDoS > 0) {
                     LOCK(cs_main);
                     Misbehaving(pfrom->GetId(), nDoS);
                 }
                 return error("invalid header received");
             }
         }
 
         {
             LOCK(cs_main);
             CNodeState *nodestate = State(pfrom->GetId());
             if (nodestate->nUnconnectingHeaders > 0) {
                 LogPrint("net",
                          "peer=%d: resetting nUnconnectingHeaders (%d -> 0)\n",
                          pfrom->id, nodestate->nUnconnectingHeaders);
             }
             nodestate->nUnconnectingHeaders = 0;
 
             assert(pindexLast);
             UpdateBlockAvailability(pfrom->GetId(), pindexLast->GetBlockHash());
 
             if (nCount == MAX_HEADERS_RESULTS) {
                 // Headers message had its maximum size; the peer may have more
                 // headers.
                 // TODO: optimize: if pindexLast is an ancestor of
                 // chainActive.Tip or pindexBestHeader, continue from there
                 // instead.
                 LogPrint(
                     "net",
                     "more getheaders (%d) to end to peer=%d (startheight:%d)\n",
                     pindexLast->nHeight, pfrom->id, pfrom->nStartingHeight);
                 connman.PushMessage(
                     pfrom, msgMaker.Make(NetMsgType::GETHEADERS,
                                          chainActive.GetLocator(pindexLast),
                                          uint256()));
             }
 
             bool fCanDirectFetch = CanDirectFetch(chainparams.GetConsensus());
             // If this set of headers is valid and ends in a block with at least
             // as much work as our tip, download as much as possible.
             if (fCanDirectFetch && pindexLast->IsValid(BLOCK_VALID_TREE) &&
                 chainActive.Tip()->nChainWork <= pindexLast->nChainWork) {
                 std::vector<const CBlockIndex *> vToFetch;
                 const CBlockIndex *pindexWalk = pindexLast;
                 // Calculate all the blocks we'd need to switch to pindexLast,
                 // up to a limit.
                 while (pindexWalk && !chainActive.Contains(pindexWalk) &&
                        vToFetch.size() <= MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
                     if (!(pindexWalk->nStatus & BLOCK_HAVE_DATA) &&
                         !mapBlocksInFlight.count(pindexWalk->GetBlockHash())) {
                         // We don't have this block, and it's not yet in flight.
                         vToFetch.push_back(pindexWalk);
                     }
                     pindexWalk = pindexWalk->pprev;
                 }
                 // If pindexWalk still isn't on our main chain, we're looking at
                 // a very large reorg at a time we think we're close to caught
                 // up to the main chain -- this shouldn't really happen. Bail
                 // out on the direct fetch and rely on parallel download
                 // instead.
                 if (!chainActive.Contains(pindexWalk)) {
                     LogPrint("net",
                              "Large reorg, won't direct fetch to %s (%d)\n",
                              pindexLast->GetBlockHash().ToString(),
                              pindexLast->nHeight);
                 } else {
                     std::vector<CInv> vGetData;
                     // Download as much as possible, from earliest to latest.
                     for (const CBlockIndex *pindex :
                          boost::adaptors::reverse(vToFetch)) {
                         if (nodestate->nBlocksInFlight >=
                             MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
                             // Can't download any more from this peer
                             break;
                         }
                         uint32_t nFetchFlags = GetFetchFlags(
                             pfrom, pindex->pprev, chainparams.GetConsensus());
                         vGetData.push_back(CInv(MSG_BLOCK | nFetchFlags,
                                                 pindex->GetBlockHash()));
                         MarkBlockAsInFlight(config, pfrom->GetId(),
                                             pindex->GetBlockHash(),
                                             chainparams.GetConsensus(), pindex);
                         LogPrint("net", "Requesting block %s from  peer=%d\n",
                                  pindex->GetBlockHash().ToString(), pfrom->id);
                     }
                     if (vGetData.size() > 1) {
                         LogPrint("net", "Downloading blocks toward %s (%d) via "
                                         "headers direct fetch\n",
                                  pindexLast->GetBlockHash().ToString(),
                                  pindexLast->nHeight);
                     }
                     if (vGetData.size() > 0) {
                         if (nodestate->fSupportsDesiredCmpctVersion &&
                             vGetData.size() == 1 &&
                             mapBlocksInFlight.size() == 1 &&
                             pindexLast->pprev->IsValid(BLOCK_VALID_CHAIN)) {
                             // In any case, we want to download using a compact
                             // block, not a regular one.
                             vGetData[0] =
                                 CInv(MSG_CMPCT_BLOCK, vGetData[0].hash);
                         }
                         connman.PushMessage(
                             pfrom,
                             msgMaker.Make(NetMsgType::GETDATA, vGetData));
                     }
                 }
             }
         }
     }
 
     else if (strCommand == NetMsgType::BLOCK && !fImporting &&
              !fReindex) // Ignore blocks received while importing
     {
         std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
         vRecv >> *pblock;
 
         LogPrint("net", "received block %s peer=%d\n",
                  pblock->GetHash().ToString(), pfrom->id);
 
         // Process all blocks from whitelisted peers, even if not requested,
         // unless we're still syncing with the network. Such an unrequested
         // block may still be processed, subject to the conditions in
         // AcceptBlock().
         bool forceProcessing = pfrom->fWhitelisted && !IsInitialBlockDownload();
         const uint256 hash(pblock->GetHash());
         {
             LOCK(cs_main);
             // Also always process if we requested the block explicitly, as we
             // may need it even though it is not a candidate for a new best tip.
             forceProcessing |= MarkBlockAsReceived(hash);
             // mapBlockSource is only used for sending reject messages and DoS
             // scores, so the race between here and cs_main in ProcessNewBlock
             // is fine.
             mapBlockSource.emplace(hash, std::make_pair(pfrom->GetId(), true));
         }
         bool fNewBlock = false;
         ProcessNewBlock(config, pblock, forceProcessing, &fNewBlock);
         if (fNewBlock) pfrom->nLastBlockTime = GetTime();
     }
 
     else if (strCommand == NetMsgType::GETADDR) {
         // This asymmetric behavior for inbound and outbound connections was
         // introduced to prevent a fingerprinting attack: an attacker can send
         // specific fake addresses to users' AddrMan and later request them by
         // sending getaddr messages. Making nodes which are behind NAT and can
         // only make outgoing connections ignore the getaddr message mitigates
         // the attack.
         if (!pfrom->fInbound) {
             LogPrint("net",
                      "Ignoring \"getaddr\" from outbound connection. peer=%d\n",
                      pfrom->id);
             return true;
         }
 
         // Only send one GetAddr response per connection to reduce resource
         // waste and discourage addr stamping of INV announcements.
         if (pfrom->fSentAddr) {
             LogPrint("net", "Ignoring repeated \"getaddr\". peer=%d\n",
                      pfrom->id);
             return true;
         }
         pfrom->fSentAddr = true;
 
         pfrom->vAddrToSend.clear();
         std::vector<CAddress> vAddr = connman.GetAddresses();
         FastRandomContext insecure_rand;
         for (const CAddress &addr : vAddr) {
             pfrom->PushAddress(addr, insecure_rand);
         }
     }
 
     else if (strCommand == NetMsgType::MEMPOOL) {
         if (!(pfrom->GetLocalServices() & NODE_BLOOM) && !pfrom->fWhitelisted) {
             LogPrint("net", "mempool request with bloom filters disabled, "
                             "disconnect peer=%d\n",
                      pfrom->GetId());
             pfrom->fDisconnect = true;
             return true;
         }
 
         if (connman.OutboundTargetReached(false) && !pfrom->fWhitelisted) {
             LogPrint("net", "mempool request with bandwidth limit reached, "
                             "disconnect peer=%d\n",
                      pfrom->GetId());
             pfrom->fDisconnect = true;
             return true;
         }
 
         LOCK(pfrom->cs_inventory);
         pfrom->fSendMempool = true;
     }
 
     else if (strCommand == NetMsgType::PING) {
         if (pfrom->nVersion > BIP0031_VERSION) {
             uint64_t nonce = 0;
             vRecv >> nonce;
             // Echo the message back with the nonce. This allows for two useful
             // features:
             //
             // 1) A remote node can quickly check if the connection is
             // operational.
             // 2) Remote nodes can measure the latency of the network thread. If
             // this node is overloaded it won't respond to pings quickly and the
             // remote node can avoid sending us more work, like chain download
             // requests.
             //
             // The nonce stops the remote getting confused between different
             // pings: without it, if the remote node sends a ping once per
             // second and this node takes 5 seconds to respond to each, the 5th
             // ping the remote sends would appear to return very quickly.
             connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::PONG, nonce));
         }
     }
 
     else if (strCommand == NetMsgType::PONG) {
         int64_t pingUsecEnd = nTimeReceived;
         uint64_t nonce = 0;
         size_t nAvail = vRecv.in_avail();
         bool bPingFinished = false;
         std::string sProblem;
 
         if (nAvail >= sizeof(nonce)) {
             vRecv >> nonce;
 
             // Only process pong message if there is an outstanding ping (old
             // ping without nonce should never pong)
             if (pfrom->nPingNonceSent != 0) {
                 if (nonce == pfrom->nPingNonceSent) {
                     // Matching pong received, this ping is no longer
                     // outstanding
                     bPingFinished = true;
                     int64_t pingUsecTime = pingUsecEnd - pfrom->nPingUsecStart;
                     if (pingUsecTime > 0) {
                         // Successful ping time measurement, replace previous
                         pfrom->nPingUsecTime = pingUsecTime;
                         pfrom->nMinPingUsecTime = std::min(
                             pfrom->nMinPingUsecTime.load(), pingUsecTime);
                     } else {
                         // This should never happen
                         sProblem = "Timing mishap";
                     }
                 } else {
                     // Nonce mismatches are normal when pings are overlapping
                     sProblem = "Nonce mismatch";
                     if (nonce == 0) {
                         // This is most likely a bug in another implementation
                         // somewhere; cancel this ping
                         bPingFinished = true;
                         sProblem = "Nonce zero";
                     }
                 }
             } else {
                 sProblem = "Unsolicited pong without ping";
             }
         } else {
             // This is most likely a bug in another implementation somewhere;
             // cancel this ping
             bPingFinished = true;
             sProblem = "Short payload";
         }
 
         if (!(sProblem.empty())) {
             LogPrint("net",
                      "pong peer=%d: %s, %x expected, %x received, %u bytes\n",
                      pfrom->id, sProblem, pfrom->nPingNonceSent, nonce, nAvail);
         }
         if (bPingFinished) {
             pfrom->nPingNonceSent = 0;
         }
     }
 
     else if (strCommand == NetMsgType::FILTERLOAD) {
         CBloomFilter filter;
         vRecv >> filter;
 
         if (!filter.IsWithinSizeConstraints()) {
             // There is no excuse for sending a too-large filter
             LOCK(cs_main);
             Misbehaving(pfrom->GetId(), 100);
         } else {
             LOCK(pfrom->cs_filter);
             delete pfrom->pfilter;
             pfrom->pfilter = new CBloomFilter(filter);
             pfrom->pfilter->UpdateEmptyFull();
             pfrom->fRelayTxes = true;
         }
     }
 
     else if (strCommand == NetMsgType::FILTERADD) {
         std::vector<unsigned char> vData;
         vRecv >> vData;
 
         // Nodes must NEVER send a data item > 520 bytes (the max size for a
         // script data object, and thus, the maximum size any matched object can
         // have) in a filteradd message.
         bool bad = false;
         if (vData.size() > MAX_SCRIPT_ELEMENT_SIZE) {
             bad = true;
         } else {
             LOCK(pfrom->cs_filter);
             if (pfrom->pfilter) {
                 pfrom->pfilter->insert(vData);
             } else {
                 bad = true;
             }
         }
         if (bad) {
             LOCK(cs_main);
             Misbehaving(pfrom->GetId(), 100);
         }
     }
 
     else if (strCommand == NetMsgType::FILTERCLEAR) {
         LOCK(pfrom->cs_filter);
         if (pfrom->GetLocalServices() & NODE_BLOOM) {
             delete pfrom->pfilter;
             pfrom->pfilter = new CBloomFilter();
         }
         pfrom->fRelayTxes = true;
     }
 
     else if (strCommand == NetMsgType::FEEFILTER) {
         CAmount newFeeFilter = 0;
         vRecv >> newFeeFilter;
         if (MoneyRange(newFeeFilter)) {
             {
                 LOCK(pfrom->cs_feeFilter);
                 pfrom->minFeeFilter = newFeeFilter;
             }
             LogPrint("net", "received: feefilter of %s from peer=%d\n",
                      CFeeRate(newFeeFilter).ToString(), pfrom->id);
         }
     }
 
     else if (strCommand == NetMsgType::NOTFOUND) {
         // We do not care about the NOTFOUND message, but logging an Unknown
         // Command message would be undesirable as we transmit it ourselves.
     }
 
     else {
         // Ignore unknown commands for extensibility
         LogPrint("net", "Unknown command \"%s\" from peer=%d\n",
                  SanitizeString(strCommand), pfrom->id);
     }
 
     return true;
 }
 
 static bool SendRejectsAndCheckIfBanned(CNode *pnode, CConnman &connman) {
     AssertLockHeld(cs_main);
     CNodeState &state = *State(pnode->GetId());
 
     for (const CBlockReject &reject : state.rejects) {
         connman.PushMessage(
             pnode, CNetMsgMaker(INIT_PROTO_VERSION)
                        .Make(NetMsgType::REJECT, (std::string)NetMsgType::BLOCK,
                              reject.chRejectCode, reject.strRejectReason,
                              reject.hashBlock));
     }
     state.rejects.clear();
 
     if (state.fShouldBan) {
         state.fShouldBan = false;
         if (pnode->fWhitelisted)
             LogPrintf("Warning: not punishing whitelisted peer %s!\n",
                       pnode->addr.ToString());
         else if (pnode->fAddnode)
             LogPrintf("Warning: not punishing addnoded peer %s!\n",
                       pnode->addr.ToString());
         else {
             pnode->fDisconnect = true;
             if (pnode->addr.IsLocal())
                 LogPrintf("Warning: not banning local peer %s!\n",
                           pnode->addr.ToString());
             else {
                 connman.Ban(pnode->addr, BanReasonNodeMisbehaving);
             }
         }
         return true;
     }
     return false;
 }
 
 bool ProcessMessages(const Config &config, CNode *pfrom, CConnman &connman,
                      const std::atomic<bool> &interruptMsgProc) {
     const CChainParams &chainparams = Params();
     //
     // Message format
     //  (4) message start
     //  (12) command
     //  (4) size
     //  (4) checksum
     //  (x) data
     //
     bool fMoreWork = false;
 
     if (!pfrom->vRecvGetData.empty())
         ProcessGetData(config, pfrom, chainparams.GetConsensus(), connman,
                        interruptMsgProc);
 
     if (pfrom->fDisconnect) return false;
 
     // this maintains the order of responses
     if (!pfrom->vRecvGetData.empty()) return true;
 
     // Don't bother if send buffer is too full to respond anyway
     if (pfrom->fPauseSend) return false;
 
     std::list<CNetMessage> msgs;
     {
         LOCK(pfrom->cs_vProcessMsg);
         if (pfrom->vProcessMsg.empty()) return false;
         // Just take one message
         msgs.splice(msgs.begin(), pfrom->vProcessMsg,
                     pfrom->vProcessMsg.begin());
         pfrom->nProcessQueueSize -=
             msgs.front().vRecv.size() + CMessageHeader::HEADER_SIZE;
         pfrom->fPauseRecv =
             pfrom->nProcessQueueSize > connman.GetReceiveFloodSize();
         fMoreWork = !pfrom->vProcessMsg.empty();
     }
     CNetMessage &msg(msgs.front());
 
     msg.SetVersion(pfrom->GetRecvVersion());
     // Scan for message start
     if (memcmp(msg.hdr.pchMessageStart, chainparams.MessageStart(),
                CMessageHeader::MESSAGE_START_SIZE) != 0) {
         LogPrintf("PROCESSMESSAGE: INVALID MESSAGESTART %s peer=%d\n",
                   SanitizeString(msg.hdr.GetCommand()), pfrom->id);
         pfrom->fDisconnect = true;
         return false;
     }
 
     // Read header
     CMessageHeader &hdr = msg.hdr;
     if (!hdr.IsValid(chainparams.MessageStart())) {
         LogPrintf("PROCESSMESSAGE: ERRORS IN HEADER %s peer=%d\n",
                   SanitizeString(hdr.GetCommand()), pfrom->id);
         return fMoreWork;
     }
     std::string strCommand = hdr.GetCommand();
 
     // Message size
     unsigned int nMessageSize = hdr.nMessageSize;
 
     // Checksum
     CDataStream &vRecv = msg.vRecv;
     const uint256 &hash = msg.GetMessageHash();
     if (memcmp(hash.begin(), hdr.pchChecksum, CMessageHeader::CHECKSUM_SIZE) !=
         0) {
         LogPrintf(
             "%s(%s, %u bytes): CHECKSUM ERROR expected %s was %s\n", __func__,
             SanitizeString(strCommand), nMessageSize,
             HexStr(hash.begin(), hash.begin() + CMessageHeader::CHECKSUM_SIZE),
             HexStr(hdr.pchChecksum,
                    hdr.pchChecksum + CMessageHeader::CHECKSUM_SIZE));
         return fMoreWork;
     }
 
     // Process message
     bool fRet = false;
     try {
         fRet = ProcessMessage(config, pfrom, strCommand, vRecv, msg.nTime,
                               chainparams, connman, interruptMsgProc);
         if (interruptMsgProc) return false;
         if (!pfrom->vRecvGetData.empty()) fMoreWork = true;
     } catch (const std::ios_base::failure &e) {
         connman.PushMessage(
             pfrom, CNetMsgMaker(INIT_PROTO_VERSION)
                        .Make(NetMsgType::REJECT, strCommand, REJECT_MALFORMED,
                              std::string("error parsing message")));
         if (strstr(e.what(), "end of data")) {
             // Allow exceptions from under-length message on vRecv
             LogPrintf(
                 "%s(%s, %u bytes): Exception '%s' caught, normally caused by a "
                 "message being shorter than its stated length\n",
                 __func__, SanitizeString(strCommand), nMessageSize, e.what());
         } else if (strstr(e.what(), "size too large")) {
             // Allow exceptions from over-long size
             LogPrintf("%s(%s, %u bytes): Exception '%s' caught\n", __func__,
                       SanitizeString(strCommand), nMessageSize, e.what());
         } else if (strstr(e.what(), "non-canonical ReadCompactSize()")) {
             // Allow exceptions from non-canonical encoding
             LogPrintf("%s(%s, %u bytes): Exception '%s' caught\n", __func__,
                       SanitizeString(strCommand), nMessageSize, e.what());
         } else {
             PrintExceptionContinue(&e, "ProcessMessages()");
         }
     } catch (const std::exception &e) {
         PrintExceptionContinue(&e, "ProcessMessages()");
     } catch (...) {
         PrintExceptionContinue(nullptr, "ProcessMessages()");
     }
 
     if (!fRet) {
         LogPrintf("%s(%s, %u bytes) FAILED peer=%d\n", __func__,
                   SanitizeString(strCommand), nMessageSize, pfrom->id);
     }
 
     LOCK(cs_main);
     SendRejectsAndCheckIfBanned(pfrom, connman);
 
     return fMoreWork;
 }
 
 class CompareInvMempoolOrder {
     CTxMemPool *mp;
 
 public:
     CompareInvMempoolOrder(CTxMemPool *_mempool) { mp = _mempool; }
 
     bool operator()(std::set<uint256>::iterator a,
                     std::set<uint256>::iterator b) {
         /* As std::make_heap produces a max-heap, we want the entries with the
          * fewest ancestors/highest fee to sort later. */
         return mp->CompareDepthAndScore(*b, *a);
     }
 };
 
 bool SendMessages(const Config &config, CNode *pto, CConnman &connman,
                   const std::atomic<bool> &interruptMsgProc) {
     const Consensus::Params &consensusParams = Params().GetConsensus();
     {
         // Don't send anything until the version handshake is complete
         if (!pto->fSuccessfullyConnected || pto->fDisconnect) return true;
 
         // If we get here, the outgoing message serialization version is set and
         // can't change.
         const CNetMsgMaker msgMaker(pto->GetSendVersion());
 
         //
         // Message: ping
         //
         bool pingSend = false;
         if (pto->fPingQueued) {
             // RPC ping request by user
             pingSend = true;
         }
         if (pto->nPingNonceSent == 0 &&
             pto->nPingUsecStart + PING_INTERVAL * 1000000 < GetTimeMicros()) {
             // Ping automatically sent as a latency probe & keepalive.
             pingSend = true;
         }
         if (pingSend) {
             uint64_t nonce = 0;
             while (nonce == 0) {
                 GetRandBytes((unsigned char *)&nonce, sizeof(nonce));
             }
             pto->fPingQueued = false;
             pto->nPingUsecStart = GetTimeMicros();
             if (pto->nVersion > BIP0031_VERSION) {
                 pto->nPingNonceSent = nonce;
                 connman.PushMessage(pto,
                                     msgMaker.Make(NetMsgType::PING, nonce));
             } else {
                 // Peer is too old to support ping command with nonce, pong will
                 // never arrive.
                 pto->nPingNonceSent = 0;
                 connman.PushMessage(pto, msgMaker.Make(NetMsgType::PING));
             }
         }
 
         // Acquire cs_main for IsInitialBlockDownload() and CNodeState()
         TRY_LOCK(cs_main, lockMain);
         if (!lockMain) return true;
 
         if (SendRejectsAndCheckIfBanned(pto, connman)) return true;
         CNodeState &state = *State(pto->GetId());
 
         // Address refresh broadcast
         int64_t nNow = GetTimeMicros();
         if (!IsInitialBlockDownload() && pto->nNextLocalAddrSend < nNow) {
             AdvertiseLocal(pto);
             pto->nNextLocalAddrSend =
                 PoissonNextSend(nNow, AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL);
         }
 
         //
         // Message: addr
         //
         if (pto->nNextAddrSend < nNow) {
             pto->nNextAddrSend =
                 PoissonNextSend(nNow, AVG_ADDRESS_BROADCAST_INTERVAL);
             std::vector<CAddress> vAddr;
             vAddr.reserve(pto->vAddrToSend.size());
             for (const CAddress &addr : pto->vAddrToSend) {
                 if (!pto->addrKnown.contains(addr.GetKey())) {
                     pto->addrKnown.insert(addr.GetKey());
                     vAddr.push_back(addr);
                     // receiver rejects addr messages larger than 1000
                     if (vAddr.size() >= 1000) {
                         connman.PushMessage(
                             pto, msgMaker.Make(NetMsgType::ADDR, vAddr));
                         vAddr.clear();
                     }
                 }
             }
             pto->vAddrToSend.clear();
             if (!vAddr.empty())
                 connman.PushMessage(pto,
                                     msgMaker.Make(NetMsgType::ADDR, vAddr));
             // we only send the big addr message once
             if (pto->vAddrToSend.capacity() > 40)
                 pto->vAddrToSend.shrink_to_fit();
         }
 
         // Start block sync
         if (pindexBestHeader == nullptr) pindexBestHeader = chainActive.Tip();
         bool fFetch = state.fPreferredDownload ||
                       (nPreferredDownload == 0 && !pto->fClient &&
                        !pto->fOneShot); // Download if this is a nice peer, or
                                         // we have no nice peers and this one
                                         // might do.
         if (!state.fSyncStarted && !pto->fClient && !fImporting && !fReindex) {
             // Only actively request headers from a single peer, unless we're
             // close to today.
             if ((nSyncStarted == 0 && fFetch) ||
                 pindexBestHeader->GetBlockTime() >
                     GetAdjustedTime() - 24 * 60 * 60) {
                 state.fSyncStarted = true;
                 nSyncStarted++;
                 const CBlockIndex *pindexStart = pindexBestHeader;
                 /* If possible, start at the block preceding the currently
                    best known header.  This ensures that we always get a
                    non-empty list of headers back as long as the peer
                    is up-to-date.  With a non-empty response, we can initialise
                    the peer's known best block.  This wouldn't be possible
                    if we requested starting at pindexBestHeader and
                    got back an empty response.  */
                 if (pindexStart->pprev) pindexStart = pindexStart->pprev;
                 LogPrint(
                     "net",
                     "initial getheaders (%d) to peer=%d (startheight:%d)\n",
                     pindexStart->nHeight, pto->id, pto->nStartingHeight);
                 connman.PushMessage(
                     pto, msgMaker.Make(NetMsgType::GETHEADERS,
                                        chainActive.GetLocator(pindexStart),
                                        uint256()));
             }
         }
 
         // Resend wallet transactions that haven't gotten in a block yet
         // Except during reindex, importing and IBD, when old wallet
         // transactions become unconfirmed and spams other nodes.
         if (!fReindex && !fImporting && !IsInitialBlockDownload()) {
             GetMainSignals().Broadcast(nTimeBestReceived, &connman);
         }
 
         //
         // Try sending block announcements via headers
         //
         {
             // If we have less than MAX_BLOCKS_TO_ANNOUNCE in our
             // list of block hashes we're relaying, and our peer wants
             // headers announcements, then find the first header
             // not yet known to our peer but would connect, and send.
             // If no header would connect, or if we have too many
             // blocks, or if the peer doesn't want headers, just
             // add all to the inv queue.
             LOCK(pto->cs_inventory);
             std::vector<CBlock> vHeaders;
             bool fRevertToInv =
                 ((!state.fPreferHeaders &&
                   (!state.fPreferHeaderAndIDs ||
                    pto->vBlockHashesToAnnounce.size() > 1)) ||
                  pto->vBlockHashesToAnnounce.size() > MAX_BLOCKS_TO_ANNOUNCE);
             // last header queued for delivery
             const CBlockIndex *pBestIndex = nullptr;
             ProcessBlockAvailability(
                 pto->id); // ensure pindexBestKnownBlock is up-to-date
 
             if (!fRevertToInv) {
                 bool fFoundStartingHeader = false;
                 // Try to find first header that our peer doesn't have, and
                 // then send all headers past that one.  If we come across any
                 // headers that aren't on chainActive, give up.
                 for (const uint256 &hash : pto->vBlockHashesToAnnounce) {
                     BlockMap::iterator mi = mapBlockIndex.find(hash);
                     assert(mi != mapBlockIndex.end());
                     const CBlockIndex *pindex = mi->second;
                     if (chainActive[pindex->nHeight] != pindex) {
                         // Bail out if we reorged away from this block
                         fRevertToInv = true;
                         break;
                     }
                     if (pBestIndex != nullptr && pindex->pprev != pBestIndex) {
                         // This means that the list of blocks to announce don't
                         // connect to each other.
                         // This shouldn't really be possible to hit during
                         // regular operation (because reorgs should take us to
                         // a chain that has some block not on the prior chain,
                         // which should be caught by the prior check), but one
                         // way this could happen is by using invalidateblock /
                         // reconsiderblock repeatedly on the tip, causing it to
                         // be added multiple times to vBlockHashesToAnnounce.
                         // Robustly deal with this rare situation by reverting
                         // to an inv.
                         fRevertToInv = true;
                         break;
                     }
                     pBestIndex = pindex;
                     if (fFoundStartingHeader) {
                         // add this to the headers message
                         vHeaders.push_back(pindex->GetBlockHeader());
                     } else if (PeerHasHeader(&state, pindex)) {
                         continue; // keep looking for the first new block
                     } else if (pindex->pprev == nullptr ||
                                PeerHasHeader(&state, pindex->pprev)) {
                         // Peer doesn't have this header but they do have the
                         // prior one.
                         // Start sending headers.
                         fFoundStartingHeader = true;
                         vHeaders.push_back(pindex->GetBlockHeader());
                     } else {
                         // Peer doesn't have this header or the prior one --
                         // nothing will connect, so bail out.
                         fRevertToInv = true;
                         break;
                     }
                 }
             }
             if (!fRevertToInv && !vHeaders.empty()) {
                 if (vHeaders.size() == 1 && state.fPreferHeaderAndIDs) {
                     // We only send up to 1 block as header-and-ids, as
                     // otherwise probably means we're doing an initial-ish-sync
                     // or they're slow.
                     LogPrint("net", "%s sending header-and-ids %s to peer=%d\n",
                              __func__, vHeaders.front().GetHash().ToString(),
                              pto->id);
 
                     int nSendFlags = 0;
 
                     bool fGotBlockFromCache = false;
                     {
                         LOCK(cs_most_recent_block);
                         if (most_recent_block_hash ==
                             pBestIndex->GetBlockHash()) {
                             CBlockHeaderAndShortTxIDs cmpctblock(
                                 *most_recent_block);
                             connman.PushMessage(
                                 pto, msgMaker.Make(nSendFlags,
                                                    NetMsgType::CMPCTBLOCK,
                                                    cmpctblock));
                             fGotBlockFromCache = true;
                         }
                     }
                     if (!fGotBlockFromCache) {
                         CBlock block;
                         bool ret = ReadBlockFromDisk(block, pBestIndex,
                                                      consensusParams);
                         assert(ret);
                         CBlockHeaderAndShortTxIDs cmpctblock(block);
                         connman.PushMessage(
                             pto,
                             msgMaker.Make(nSendFlags, NetMsgType::CMPCTBLOCK,
                                           cmpctblock));
                     }
                     state.pindexBestHeaderSent = pBestIndex;
                 } else if (state.fPreferHeaders) {
                     if (vHeaders.size() > 1) {
                         LogPrint("net",
                                  "%s: %u headers, range (%s, %s), to peer=%d\n",
                                  __func__, vHeaders.size(),
                                  vHeaders.front().GetHash().ToString(),
                                  vHeaders.back().GetHash().ToString(), pto->id);
                     } else {
                         LogPrint("net", "%s: sending header %s to peer=%d\n",
                                  __func__,
                                  vHeaders.front().GetHash().ToString(),
                                  pto->id);
                     }
                     connman.PushMessage(
                         pto, msgMaker.Make(NetMsgType::HEADERS, vHeaders));
                     state.pindexBestHeaderSent = pBestIndex;
                 } else
                     fRevertToInv = true;
             }
             if (fRevertToInv) {
                 // If falling back to using an inv, just try to inv the tip. The
                 // last entry in vBlockHashesToAnnounce was our tip at some
                 // point in the past.
                 if (!pto->vBlockHashesToAnnounce.empty()) {
                     const uint256 &hashToAnnounce =
                         pto->vBlockHashesToAnnounce.back();
                     BlockMap::iterator mi = mapBlockIndex.find(hashToAnnounce);
                     assert(mi != mapBlockIndex.end());
                     const CBlockIndex *pindex = mi->second;
 
                     // Warn if we're announcing a block that is not on the main
                     // chain. This should be very rare and could be optimized
                     // out. Just log for now.
                     if (chainActive[pindex->nHeight] != pindex) {
                         LogPrint(
                             "net",
                             "Announcing block %s not on main chain (tip=%s)\n",
                             hashToAnnounce.ToString(),
                             chainActive.Tip()->GetBlockHash().ToString());
                     }
 
                     // If the peer's chain has this block, don't inv it back.
                     if (!PeerHasHeader(&state, pindex)) {
                         pto->PushInventory(CInv(MSG_BLOCK, hashToAnnounce));
                         LogPrint("net", "%s: sending inv peer=%d hash=%s\n",
                                  __func__, pto->id, hashToAnnounce.ToString());
                     }
                 }
             }
             pto->vBlockHashesToAnnounce.clear();
         }
 
         //
         // Message: inventory
         //
         std::vector<CInv> vInv;
         {
             LOCK(pto->cs_inventory);
             vInv.reserve(std::max<size_t>(pto->vInventoryBlockToSend.size(),
                                           INVENTORY_BROADCAST_MAX));
 
             // Add blocks
             for (const uint256 &hash : pto->vInventoryBlockToSend) {
                 vInv.push_back(CInv(MSG_BLOCK, hash));
                 if (vInv.size() == MAX_INV_SZ) {
                     connman.PushMessage(pto,
                                         msgMaker.Make(NetMsgType::INV, vInv));
                     vInv.clear();
                 }
             }
             pto->vInventoryBlockToSend.clear();
 
             // Check whether periodic sends should happen
             bool fSendTrickle = pto->fWhitelisted;
             if (pto->nNextInvSend < nNow) {
                 fSendTrickle = true;
                 // Use half the delay for outbound peers, as there is less
                 // privacy concern for them.
                 pto->nNextInvSend = PoissonNextSend(
                     nNow, INVENTORY_BROADCAST_INTERVAL >> !pto->fInbound);
             }
 
             // Time to send but the peer has requested we not relay
             // transactions.
             if (fSendTrickle) {
                 LOCK(pto->cs_filter);
                 if (!pto->fRelayTxes) pto->setInventoryTxToSend.clear();
             }
 
             // Respond to BIP35 mempool requests
             if (fSendTrickle && pto->fSendMempool) {
                 auto vtxinfo = mempool.infoAll();
                 pto->fSendMempool = false;
                 CAmount filterrate = 0;
                 {
                     LOCK(pto->cs_feeFilter);
                     filterrate = pto->minFeeFilter;
                 }
 
                 LOCK(pto->cs_filter);
 
                 for (const auto &txinfo : vtxinfo) {
                     const uint256 &txid = txinfo.tx->GetId();
                     CInv inv(MSG_TX, txid);
                     pto->setInventoryTxToSend.erase(txid);
                     if (filterrate) {
                         if (txinfo.feeRate.GetFeePerK() < filterrate) continue;
                     }
                     if (pto->pfilter) {
                         if (!pto->pfilter->IsRelevantAndUpdate(*txinfo.tx))
                             continue;
                     }
                     pto->filterInventoryKnown.insert(txid);
                     vInv.push_back(inv);
                     if (vInv.size() == MAX_INV_SZ) {
                         connman.PushMessage(
                             pto, msgMaker.Make(NetMsgType::INV, vInv));
                         vInv.clear();
                     }
                 }
                 pto->timeLastMempoolReq = GetTime();
             }
 
             // Determine transactions to relay
             if (fSendTrickle) {
                 // Produce a vector with all candidates for sending
                 std::vector<std::set<uint256>::iterator> vInvTx;
                 vInvTx.reserve(pto->setInventoryTxToSend.size());
                 for (std::set<uint256>::iterator it =
                          pto->setInventoryTxToSend.begin();
                      it != pto->setInventoryTxToSend.end(); it++) {
                     vInvTx.push_back(it);
                 }
                 CAmount filterrate = 0;
                 {
                     LOCK(pto->cs_feeFilter);
                     filterrate = pto->minFeeFilter;
                 }
                 // Topologically and fee-rate sort the inventory we send for
                 // privacy and priority reasons. A heap is used so that not all
                 // items need sorting if only a few are being sent.
                 CompareInvMempoolOrder compareInvMempoolOrder(&mempool);
                 std::make_heap(vInvTx.begin(), vInvTx.end(),
                                compareInvMempoolOrder);
                 // No reason to drain out at many times the network's capacity,
                 // especially since we have many peers and some will draw much
                 // shorter delays.
                 unsigned int nRelayedTransactions = 0;
                 LOCK(pto->cs_filter);
                 while (!vInvTx.empty() &&
                        nRelayedTransactions < INVENTORY_BROADCAST_MAX) {
                     // Fetch the top element from the heap
                     std::pop_heap(vInvTx.begin(), vInvTx.end(),
                                   compareInvMempoolOrder);
                     std::set<uint256>::iterator it = vInvTx.back();
                     vInvTx.pop_back();
                     uint256 hash = *it;
                     // Remove it from the to-be-sent set
                     pto->setInventoryTxToSend.erase(it);
                     // Check if not in the filter already
                     if (pto->filterInventoryKnown.contains(hash)) {
                         continue;
                     }
                     // Not in the mempool anymore? don't bother sending it.
                     auto txinfo = mempool.info(hash);
                     if (!txinfo.tx) {
                         continue;
                     }
                     if (filterrate &&
                         txinfo.feeRate.GetFeePerK() < filterrate) {
                         continue;
                     }
                     if (pto->pfilter &&
                         !pto->pfilter->IsRelevantAndUpdate(*txinfo.tx))
                         continue;
                     // Send
                     vInv.push_back(CInv(MSG_TX, hash));
                     nRelayedTransactions++;
                     {
                         // Expire old relay messages
                         while (!vRelayExpiration.empty() &&
                                vRelayExpiration.front().first < nNow) {
                             mapRelay.erase(vRelayExpiration.front().second);
                             vRelayExpiration.pop_front();
                         }
 
                         auto ret = mapRelay.insert(
                             std::make_pair(hash, std::move(txinfo.tx)));
                         if (ret.second) {
                             vRelayExpiration.push_back(std::make_pair(
                                 nNow + 15 * 60 * 1000000, ret.first));
                         }
                     }
                     if (vInv.size() == MAX_INV_SZ) {
                         connman.PushMessage(
                             pto, msgMaker.Make(NetMsgType::INV, vInv));
                         vInv.clear();
                     }
                     pto->filterInventoryKnown.insert(hash);
                 }
             }
         }
         if (!vInv.empty())
             connman.PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv));
 
         // Detect whether we're stalling
         nNow = GetTimeMicros();
         if (state.nStallingSince &&
             state.nStallingSince < nNow - 1000000 * BLOCK_STALLING_TIMEOUT) {
             // Stalling only triggers when the block download window cannot
             // move. During normal steady state, the download window should be
             // much larger than the to-be-downloaded set of blocks, so
             // disconnection should only happen during initial block download.
             LogPrintf("Peer=%d is stalling block download, disconnecting\n",
                       pto->id);
             pto->fDisconnect = true;
             return true;
         }
         // In case there is a block that has been in flight from this peer for 2
         // + 0.5 * N times the block interval (with N the number of peers from
         // which we're downloading validated blocks), disconnect due to timeout.
         // We compensate for other peers to prevent killing off peers due to our
         // own downstream link being saturated. We only count validated
         // in-flight blocks so peers can't advertise non-existing block hashes
         // to unreasonably increase our timeout.
         if (state.vBlocksInFlight.size() > 0) {
             QueuedBlock &queuedBlock = state.vBlocksInFlight.front();
             int nOtherPeersWithValidatedDownloads =
                 nPeersWithValidatedDownloads -
                 (state.nBlocksInFlightValidHeaders > 0);
             if (nNow > state.nDownloadingSince +
                            consensusParams.nPowTargetSpacing *
                                (BLOCK_DOWNLOAD_TIMEOUT_BASE +
                                 BLOCK_DOWNLOAD_TIMEOUT_PER_PEER *
                                     nOtherPeersWithValidatedDownloads)) {
                 LogPrintf("Timeout downloading block %s from peer=%d, "
                           "disconnecting\n",
                           queuedBlock.hash.ToString(), pto->id);
                 pto->fDisconnect = true;
                 return true;
             }
         }
 
         //
         // Message: getdata (blocks)
         //
         std::vector<CInv> vGetData;
         if (!pto->fClient && (fFetch || !IsInitialBlockDownload()) &&
             state.nBlocksInFlight < MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
             std::vector<const CBlockIndex *> vToDownload;
             NodeId staller = -1;
             FindNextBlocksToDownload(pto->GetId(),
                                      MAX_BLOCKS_IN_TRANSIT_PER_PEER -
                                          state.nBlocksInFlight,
                                      vToDownload, staller, consensusParams);
             for (const CBlockIndex *pindex : vToDownload) {
                 uint32_t nFetchFlags =
                     GetFetchFlags(pto, pindex->pprev, consensusParams);
                 vGetData.push_back(
                     CInv(MSG_BLOCK | nFetchFlags, pindex->GetBlockHash()));
                 MarkBlockAsInFlight(config, pto->GetId(),
                                     pindex->GetBlockHash(), consensusParams,
                                     pindex);
                 LogPrint("net", "Requesting block %s (%d) peer=%d\n",
                          pindex->GetBlockHash().ToString(), pindex->nHeight,
                          pto->id);
             }
             if (state.nBlocksInFlight == 0 && staller != -1) {
                 if (State(staller)->nStallingSince == 0) {
                     State(staller)->nStallingSince = nNow;
                     LogPrint("net", "Stall started peer=%d\n", staller);
                 }
             }
         }
 
         //
         // Message: getdata (non-blocks)
         //
         while (!pto->mapAskFor.empty() &&
                (*pto->mapAskFor.begin()).first <= nNow) {
             const CInv &inv = (*pto->mapAskFor.begin()).second;
             if (!AlreadyHave(inv)) {
                 if (fDebug)
                     LogPrint("net", "Requesting %s peer=%d\n", inv.ToString(),
                              pto->id);
                 vGetData.push_back(inv);
                 if (vGetData.size() >= 1000) {
                     connman.PushMessage(
                         pto, msgMaker.Make(NetMsgType::GETDATA, vGetData));
                     vGetData.clear();
                 }
             } else {
                 // If we're not going to ask, don't expect a response.
                 pto->setAskFor.erase(inv.hash);
             }
             pto->mapAskFor.erase(pto->mapAskFor.begin());
         }
         if (!vGetData.empty())
             connman.PushMessage(pto,
                                 msgMaker.Make(NetMsgType::GETDATA, vGetData));
 
         //
         // Message: feefilter
         //
         // We don't want white listed peers to filter txs to us if we have
         // -whitelistforcerelay
         if (pto->nVersion >= FEEFILTER_VERSION &&
             GetBoolArg("-feefilter", DEFAULT_FEEFILTER) &&
             !(pto->fWhitelisted && GetBoolArg("-whitelistforcerelay",
                                               DEFAULT_WHITELISTFORCERELAY))) {
             CAmount currentFilter =
                 mempool
                     .GetMinFee(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) *
                                1000000)
                     .GetFeePerK();
             int64_t timeNow = GetTimeMicros();
             if (timeNow > pto->nextSendTimeFeeFilter) {
                 static CFeeRate default_feerate(DEFAULT_MIN_RELAY_TX_FEE);
                 static FeeFilterRounder filterRounder(default_feerate);
                 CAmount filterToSend = filterRounder.round(currentFilter);
                 // If we don't allow free transactions, then we always have a
                 // fee filter of at least minRelayTxFee
                 if (GetArg("-limitfreerelay", DEFAULT_LIMITFREERELAY) <= 0)
                     filterToSend =
                         std::max(filterToSend, ::minRelayTxFee.GetFeePerK());
                 if (filterToSend != pto->lastSentFeeFilter) {
                     connman.PushMessage(
                         pto,
                         msgMaker.Make(NetMsgType::FEEFILTER, filterToSend));
                     pto->lastSentFeeFilter = filterToSend;
                 }
                 pto->nextSendTimeFeeFilter =
                     PoissonNextSend(timeNow, AVG_FEEFILTER_BROADCAST_INTERVAL);
             }
             // If the fee filter has changed substantially and it's still more
             // than MAX_FEEFILTER_CHANGE_DELAY until scheduled broadcast, then
             // move the broadcast to within MAX_FEEFILTER_CHANGE_DELAY.
             else if (timeNow + MAX_FEEFILTER_CHANGE_DELAY * 1000000 <
                          pto->nextSendTimeFeeFilter &&
                      (currentFilter < 3 * pto->lastSentFeeFilter / 4 ||
                       currentFilter > 4 * pto->lastSentFeeFilter / 3)) {
                 pto->nextSendTimeFeeFilter =
                     timeNow + GetRandInt(MAX_FEEFILTER_CHANGE_DELAY) * 1000000;
             }
         }
     }
     return true;
 }
 
 class CNetProcessingCleanup {
 public:
     CNetProcessingCleanup() {}
     ~CNetProcessingCleanup() {
         // orphan transactions
         mapOrphanTransactions.clear();
         mapOrphanTransactionsByPrev.clear();
     }
 } instance_of_cnetprocessingcleanup;
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index 0ae6c953e..e925134f9 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -1,1220 +1,1220 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include "txmempool.h"
 
 #include "chainparams.h" // for GetConsensus.
 #include "clientversion.h"
 #include "config.h"
 #include "consensus/consensus.h"
 #include "consensus/validation.h"
 #include "policy/fees.h"
 #include "policy/policy.h"
 #include "streams.h"
 #include "timedata.h"
 #include "util.h"
 #include "utilmoneystr.h"
 #include "utiltime.h"
 #include "validation.h"
 #include "version.h"
 
 #include <boost/range/adaptor/reversed.hpp>
 
 CTxMemPoolEntry::CTxMemPoolEntry(const CTransactionRef &_tx,
                                  const CAmount &_nFee, int64_t _nTime,
                                  double _entryPriority,
                                  unsigned int _entryHeight,
                                  CAmount _inChainInputValue,
                                  bool _spendsCoinbase, int64_t _sigOpsCount,
                                  LockPoints lp)
     : tx(_tx), nFee(_nFee), nTime(_nTime), entryPriority(_entryPriority),
       entryHeight(_entryHeight), inChainInputValue(_inChainInputValue),
       spendsCoinbase(_spendsCoinbase), sigOpCount(_sigOpsCount),
       lockPoints(lp) {
     nTxSize = GetTransactionSize(*tx);
     nModSize = tx->CalculateModifiedSize(GetTxSize());
     nUsageSize = RecursiveDynamicUsage(*tx) + memusage::DynamicUsage(tx);
 
     nCountWithDescendants = 1;
     nSizeWithDescendants = GetTxSize();
     nModFeesWithDescendants = nFee;
     CAmount nValueIn = tx->GetValueOut() + nFee;
     assert(inChainInputValue <= nValueIn);
 
     feeDelta = 0;
 
     nCountWithAncestors = 1;
     nSizeWithAncestors = GetTxSize();
     nModFeesWithAncestors = nFee;
     nSigOpCountWithAncestors = sigOpCount;
 }
 
 CTxMemPoolEntry::CTxMemPoolEntry(const CTxMemPoolEntry &other) {
     *this = other;
 }
 
 double CTxMemPoolEntry::GetPriority(unsigned int currentHeight) const {
     double deltaPriority =
         ((double)(currentHeight - entryHeight) * inChainInputValue) / nModSize;
     double dResult = entryPriority + deltaPriority;
     // This should only happen if it was called with a height below entry height
     if (dResult < 0) dResult = 0;
     return dResult;
 }
 
 void CTxMemPoolEntry::UpdateFeeDelta(int64_t newFeeDelta) {
     nModFeesWithDescendants += newFeeDelta - feeDelta;
     nModFeesWithAncestors += newFeeDelta - feeDelta;
     feeDelta = newFeeDelta;
 }
 
 void CTxMemPoolEntry::UpdateLockPoints(const LockPoints &lp) {
     lockPoints = lp;
 }
 
 // Update the given tx for any in-mempool descendants.
 // Assumes that setMemPoolChildren is correct for the given tx and all
 // descendants.
 void CTxMemPool::UpdateForDescendants(txiter updateIt,
                                       cacheMap &cachedDescendants,
                                       const std::set<uint256> &setExclude) {
     setEntries stageEntries, setAllDescendants;
     stageEntries = GetMemPoolChildren(updateIt);
 
     while (!stageEntries.empty()) {
         const txiter cit = *stageEntries.begin();
         setAllDescendants.insert(cit);
         stageEntries.erase(cit);
         const setEntries &setChildren = GetMemPoolChildren(cit);
         for (const txiter childEntry : setChildren) {
             cacheMap::iterator cacheIt = cachedDescendants.find(childEntry);
             if (cacheIt != cachedDescendants.end()) {
                 // We've already calculated this one, just add the entries for
                 // this set but don't traverse again.
                 for (const txiter cacheEntry : cacheIt->second) {
                     setAllDescendants.insert(cacheEntry);
                 }
             } else if (!setAllDescendants.count(childEntry)) {
                 // Schedule for later processing
                 stageEntries.insert(childEntry);
             }
         }
     }
     // setAllDescendants now contains all in-mempool descendants of updateIt.
     // Update and add to cached descendant map
     int64_t modifySize = 0;
     CAmount modifyFee = 0;
     int64_t modifyCount = 0;
     for (txiter cit : setAllDescendants) {
         if (!setExclude.count(cit->GetTx().GetId())) {
             modifySize += cit->GetTxSize();
             modifyFee += cit->GetModifiedFee();
             modifyCount++;
             cachedDescendants[updateIt].insert(cit);
             // Update ancestor state for each descendant
             mapTx.modify(cit,
                          update_ancestor_state(updateIt->GetTxSize(),
                                                updateIt->GetModifiedFee(), 1,
                                                updateIt->GetSigOpCount()));
         }
     }
     mapTx.modify(updateIt,
                  update_descendant_state(modifySize, modifyFee, modifyCount));
 }
 
 // vHashesToUpdate is the set of transaction hashes from a disconnected block
 // which has been re-added to the mempool. For each entry, look for descendants
 // that are outside hashesToUpdate, and add fee/size information for such
 // descendants to the parent. For each such descendant, also update the ancestor
 // state to include the parent.
 void CTxMemPool::UpdateTransactionsFromBlock(
     const std::vector<uint256> &vHashesToUpdate) {
     LOCK(cs);
     // For each entry in vHashesToUpdate, store the set of in-mempool, but not
     // in-vHashesToUpdate transactions, so that we don't have to recalculate
     // descendants when we come across a previously seen entry.
     cacheMap mapMemPoolDescendantsToUpdate;
 
     // Use a set for lookups into vHashesToUpdate (these entries are already
     // accounted for in the state of their ancestors)
     std::set<uint256> setAlreadyIncluded(vHashesToUpdate.begin(),
                                          vHashesToUpdate.end());
 
     // Iterate in reverse, so that whenever we are looking at at a transaction
     // we are sure that all in-mempool descendants have already been processed.
     // This maximizes the benefit of the descendant cache and guarantees that
     // setMemPoolChildren will be updated, an assumption made in
     // UpdateForDescendants.
     for (const uint256 &hash : boost::adaptors::reverse(vHashesToUpdate)) {
         // we cache the in-mempool children to avoid duplicate updates
         setEntries setChildren;
         // calculate children from mapNextTx
         txiter it = mapTx.find(hash);
         if (it == mapTx.end()) {
             continue;
         }
         auto iter = mapNextTx.lower_bound(COutPoint(hash, 0));
         // First calculate the children, and update setMemPoolChildren to
         // include them, and update their setMemPoolParents to include this tx.
         for (; iter != mapNextTx.end() && iter->first->hash == hash; ++iter) {
             const uint256 &childHash = iter->second->GetId();
             txiter childIter = mapTx.find(childHash);
             assert(childIter != mapTx.end());
             // We can skip updating entries we've encountered before or that are
             // in the block (which are already accounted for).
             if (setChildren.insert(childIter).second &&
                 !setAlreadyIncluded.count(childHash)) {
                 UpdateChild(it, childIter, true);
                 UpdateParent(childIter, it, true);
             }
         }
         UpdateForDescendants(it, mapMemPoolDescendantsToUpdate,
                              setAlreadyIncluded);
     }
 }
 
 bool CTxMemPool::CalculateMemPoolAncestors(
     const CTxMemPoolEntry &entry, setEntries &setAncestors,
     uint64_t limitAncestorCount, uint64_t limitAncestorSize,
     uint64_t limitDescendantCount, uint64_t limitDescendantSize,
     std::string &errString, bool fSearchForParents /* = true */) const {
     LOCK(cs);
 
     setEntries parentHashes;
     const CTransaction &tx = entry.GetTx();
 
     if (fSearchForParents) {
         // Get parents of this transaction that are in the mempool
         // GetMemPoolParents() is only valid for entries in the mempool, so we
         // iterate mapTx to find parents.
         for (unsigned int i = 0; i < tx.vin.size(); i++) {
             txiter piter = mapTx.find(tx.vin[i].prevout.hash);
             if (piter != mapTx.end()) {
                 parentHashes.insert(piter);
                 if (parentHashes.size() + 1 > limitAncestorCount) {
                     errString =
                         strprintf("too many unconfirmed parents [limit: %u]",
                                   limitAncestorCount);
                     return false;
                 }
             }
         }
     } else {
         // If we're not searching for parents, we require this to be an entry in
         // the mempool already.
         txiter it = mapTx.iterator_to(entry);
         parentHashes = GetMemPoolParents(it);
     }
 
     size_t totalSizeWithAncestors = entry.GetTxSize();
 
     while (!parentHashes.empty()) {
         txiter stageit = *parentHashes.begin();
 
         setAncestors.insert(stageit);
         parentHashes.erase(stageit);
         totalSizeWithAncestors += stageit->GetTxSize();
 
         if (stageit->GetSizeWithDescendants() + entry.GetTxSize() >
             limitDescendantSize) {
             errString = strprintf(
                 "exceeds descendant size limit for tx %s [limit: %u]",
                 stageit->GetTx().GetId().ToString(), limitDescendantSize);
             return false;
         } else if (stageit->GetCountWithDescendants() + 1 >
                    limitDescendantCount) {
             errString = strprintf("too many descendants for tx %s [limit: %u]",
                                   stageit->GetTx().GetId().ToString(),
                                   limitDescendantCount);
             return false;
         } else if (totalSizeWithAncestors > limitAncestorSize) {
             errString = strprintf("exceeds ancestor size limit [limit: %u]",
                                   limitAncestorSize);
             return false;
         }
 
         const setEntries &setMemPoolParents = GetMemPoolParents(stageit);
         for (const txiter &phash : setMemPoolParents) {
             // If this is a new ancestor, add it.
             if (setAncestors.count(phash) == 0) {
                 parentHashes.insert(phash);
             }
             if (parentHashes.size() + setAncestors.size() + 1 >
                 limitAncestorCount) {
                 errString =
                     strprintf("too many unconfirmed ancestors [limit: %u]",
                               limitAncestorCount);
                 return false;
             }
         }
     }
 
     return true;
 }
 
 void CTxMemPool::UpdateAncestorsOf(bool add, txiter it,
                                    setEntries &setAncestors) {
     setEntries parentIters = GetMemPoolParents(it);
     // add or remove this tx as a child of each parent
     for (txiter piter : parentIters) {
         UpdateChild(piter, it, add);
     }
     const int64_t updateCount = (add ? 1 : -1);
     const int64_t updateSize = updateCount * it->GetTxSize();
     const CAmount updateFee = updateCount * it->GetModifiedFee();
     for (txiter ancestorIt : setAncestors) {
         mapTx.modify(ancestorIt, update_descendant_state(updateSize, updateFee,
                                                          updateCount));
     }
 }
 
 void CTxMemPool::UpdateEntryForAncestors(txiter it,
                                          const setEntries &setAncestors) {
     int64_t updateCount = setAncestors.size();
     int64_t updateSize = 0;
     CAmount updateFee = 0;
     int64_t updateSigOpsCount = 0;
     for (txiter ancestorIt : setAncestors) {
         updateSize += ancestorIt->GetTxSize();
         updateFee += ancestorIt->GetModifiedFee();
         updateSigOpsCount += ancestorIt->GetSigOpCount();
     }
     mapTx.modify(it, update_ancestor_state(updateSize, updateFee, updateCount,
                                            updateSigOpsCount));
 }
 
 void CTxMemPool::UpdateChildrenForRemoval(txiter it) {
     const setEntries &setMemPoolChildren = GetMemPoolChildren(it);
     for (txiter updateIt : setMemPoolChildren) {
         UpdateParent(updateIt, it, false);
     }
 }
 
 void CTxMemPool::UpdateForRemoveFromMempool(const setEntries &entriesToRemove,
                                             bool updateDescendants) {
     // For each entry, walk back all ancestors and decrement size associated
     // with this transaction.
     const uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
     if (updateDescendants) {
         // updateDescendants should be true whenever we're not recursively
         // removing a tx and all its descendants, eg when a transaction is
         // confirmed in a block. Here we only update statistics and not data in
         // mapLinks (which we need to preserve until we're finished with all
         // operations that need to traverse the mempool).
         for (txiter removeIt : entriesToRemove) {
             setEntries setDescendants;
             CalculateDescendants(removeIt, setDescendants);
             setDescendants.erase(removeIt); // don't update state for self
             int64_t modifySize = -((int64_t)removeIt->GetTxSize());
             CAmount modifyFee = -removeIt->GetModifiedFee();
             int modifySigOps = -removeIt->GetSigOpCount();
             for (txiter dit : setDescendants) {
                 mapTx.modify(dit, update_ancestor_state(modifySize, modifyFee,
                                                         -1, modifySigOps));
             }
         }
     }
 
     for (txiter removeIt : entriesToRemove) {
         setEntries setAncestors;
         const CTxMemPoolEntry &entry = *removeIt;
         std::string dummy;
         // Since this is a tx that is already in the mempool, we can call CMPA
         // with fSearchForParents = false.  If the mempool is in a consistent
         // state, then using true or false should both be correct, though false
         // should be a bit faster.
         // However, if we happen to be in the middle of processing a reorg, then
         // the mempool can be in an inconsistent state. In this case, the set of
         // ancestors reachable via mapLinks will be the same as the set of
         // ancestors whose packages include this transaction, because when we
         // add a new transaction to the mempool in addUnchecked(), we assume it
         // has no children, and in the case of a reorg where that assumption is
         // false, the in-mempool children aren't linked to the in-block tx's
         // until UpdateTransactionsFromBlock() is called. So if we're being
         // called during a reorg, ie before UpdateTransactionsFromBlock() has
         // been called, then mapLinks[] will differ from the set of mempool
         // parents we'd calculate by searching, and it's important that we use
         // the mapLinks[] notion of ancestor transactions as the set of things
         // to update for removal.
         CalculateMemPoolAncestors(entry, setAncestors, nNoLimit, nNoLimit,
                                   nNoLimit, nNoLimit, dummy, false);
         // Note that UpdateAncestorsOf severs the child links that point to
         // removeIt in the entries for the parents of removeIt.
         UpdateAncestorsOf(false, removeIt, setAncestors);
     }
     // After updating all the ancestor sizes, we can now sever the link between
     // each transaction being removed and any mempool children (ie, update
     // setMemPoolParents for each direct child of a transaction being removed).
     for (txiter removeIt : entriesToRemove) {
         UpdateChildrenForRemoval(removeIt);
     }
 }
 
 void CTxMemPoolEntry::UpdateDescendantState(int64_t modifySize,
                                             CAmount modifyFee,
                                             int64_t modifyCount) {
     nSizeWithDescendants += modifySize;
     assert(int64_t(nSizeWithDescendants) > 0);
     nModFeesWithDescendants += modifyFee;
     nCountWithDescendants += modifyCount;
     assert(int64_t(nCountWithDescendants) > 0);
 }
 
 void CTxMemPoolEntry::UpdateAncestorState(int64_t modifySize, CAmount modifyFee,
                                           int64_t modifyCount,
                                           int modifySigOps) {
     nSizeWithAncestors += modifySize;
     assert(int64_t(nSizeWithAncestors) > 0);
     nModFeesWithAncestors += modifyFee;
     nCountWithAncestors += modifyCount;
     assert(int64_t(nCountWithAncestors) > 0);
     nSigOpCountWithAncestors += modifySigOps;
     assert(int(nSigOpCountWithAncestors) >= 0);
 }
 
 CTxMemPool::CTxMemPool(const CFeeRate &_minReasonableRelayFee)
     : nTransactionsUpdated(0) {
     // lock free clear
     _clear();
 
     // Sanity checks off by default for performance, because otherwise accepting
     // transactions becomes O(N^2) where N is the number of transactions in the
     // pool
     nCheckFrequency = 0;
 
     minerPolicyEstimator = new CBlockPolicyEstimator(_minReasonableRelayFee);
 }
 
 CTxMemPool::~CTxMemPool() {
     delete minerPolicyEstimator;
 }
 
 void CTxMemPool::pruneSpent(const uint256 &txid, CCoins &coins) {
     LOCK(cs);
 
     auto it = mapNextTx.lower_bound(COutPoint(txid, 0));
 
     // iterate over all COutPoints in mapNextTx whose hash equals the provided
     // hashTx
     while (it != mapNextTx.end() && it->first->hash == txid) {
         // and remove those outputs from coins
         coins.Spend(it->first->n);
         it++;
     }
 }
 
 unsigned int CTxMemPool::GetTransactionsUpdated() const {
     LOCK(cs);
     return nTransactionsUpdated;
 }
 
 void CTxMemPool::AddTransactionsUpdated(unsigned int n) {
     LOCK(cs);
     nTransactionsUpdated += n;
 }
 
 bool CTxMemPool::addUnchecked(const uint256 &hash, const CTxMemPoolEntry &entry,
                               setEntries &setAncestors, bool validFeeEstimate) {
     NotifyEntryAdded(entry.GetSharedTx());
     // Add to memory pool without checking anything.
     // Used by AcceptToMemoryPool(), which DOES do all the appropriate checks.
     LOCK(cs);
     indexed_transaction_set::iterator newit = mapTx.insert(entry).first;
     mapLinks.insert(make_pair(newit, TxLinks()));
 
     // Update transaction for any feeDelta created by PrioritiseTransaction
     // TODO: refactor so that the fee delta is calculated before inserting into
     // mapTx.
     std::map<uint256, std::pair<double, CAmount>>::const_iterator pos =
         mapDeltas.find(hash);
     if (pos != mapDeltas.end()) {
         const std::pair<double, CAmount> &deltas = pos->second;
         if (deltas.second) {
             mapTx.modify(newit, update_fee_delta(deltas.second));
         }
     }
 
     // Update cachedInnerUsage to include contained transaction's usage.
     // (When we update the entry for in-mempool parents, memory usage will be
     // further updated.)
     cachedInnerUsage += entry.DynamicMemoryUsage();
 
     const CTransaction &tx = newit->GetTx();
     std::set<uint256> setParentTransactions;
     for (unsigned int i = 0; i < tx.vin.size(); i++) {
         mapNextTx.insert(std::make_pair(&tx.vin[i].prevout, &tx));
         setParentTransactions.insert(tx.vin[i].prevout.hash);
     }
     // Don't bother worrying about child transactions of this one. Normal case
     // of a new transaction arriving is that there can't be any children,
     // because such children would be orphans. An exception to that is if a
     // transaction enters that used to be in a block. In that case, our
     // disconnect block logic will call UpdateTransactionsFromBlock to clean up
     // the mess we're leaving here.
 
     // Update ancestors with information about this tx
     for (const uint256 &phash : setParentTransactions) {
         txiter pit = mapTx.find(phash);
         if (pit != mapTx.end()) {
             UpdateParent(newit, pit, true);
         }
     }
     UpdateAncestorsOf(true, newit, setAncestors);
     UpdateEntryForAncestors(newit, setAncestors);
 
     nTransactionsUpdated++;
     totalTxSize += entry.GetTxSize();
     minerPolicyEstimator->processTransaction(entry, validFeeEstimate);
 
     vTxHashes.emplace_back(tx.GetHash(), newit);
     newit->vTxHashesIdx = vTxHashes.size() - 1;
 
     return true;
 }
 
 void CTxMemPool::removeUnchecked(txiter it, MemPoolRemovalReason reason) {
     NotifyEntryRemoved(it->GetSharedTx(), reason);
     const uint256 txid = it->GetTx().GetId();
     for (const CTxIn &txin : it->GetTx().vin) {
         mapNextTx.erase(txin.prevout);
     }
 
     if (vTxHashes.size() > 1) {
         vTxHashes[it->vTxHashesIdx] = std::move(vTxHashes.back());
         vTxHashes[it->vTxHashesIdx].second->vTxHashesIdx = it->vTxHashesIdx;
         vTxHashes.pop_back();
         if (vTxHashes.size() * 2 < vTxHashes.capacity())
             vTxHashes.shrink_to_fit();
     } else
         vTxHashes.clear();
 
     totalTxSize -= it->GetTxSize();
     cachedInnerUsage -= it->DynamicMemoryUsage();
     cachedInnerUsage -= memusage::DynamicUsage(mapLinks[it].parents) +
                         memusage::DynamicUsage(mapLinks[it].children);
     mapLinks.erase(it);
     mapTx.erase(it);
     nTransactionsUpdated++;
     minerPolicyEstimator->removeTx(txid);
 }
 
 // Calculates descendants of entry that are not already in setDescendants, and
 // adds to setDescendants. Assumes entryit is already a tx in the mempool and
 // setMemPoolChildren is correct for tx and all descendants. Also assumes that
 // if an entry is in setDescendants already, then all in-mempool descendants of
 // it are already in setDescendants as well, so that we can save time by not
 // iterating over those entries.
 void CTxMemPool::CalculateDescendants(txiter entryit,
                                       setEntries &setDescendants) {
     setEntries stage;
     if (setDescendants.count(entryit) == 0) {
         stage.insert(entryit);
     }
     // Traverse down the children of entry, only adding children that are not
     // accounted for in setDescendants already (because those children have
     // either already been walked, or will be walked in this iteration).
     while (!stage.empty()) {
         txiter it = *stage.begin();
         setDescendants.insert(it);
         stage.erase(it);
 
         const setEntries &setChildren = GetMemPoolChildren(it);
         for (const txiter &childiter : setChildren) {
             if (!setDescendants.count(childiter)) {
                 stage.insert(childiter);
             }
         }
     }
 }
 
 void CTxMemPool::removeRecursive(const CTransaction &origTx,
                                  MemPoolRemovalReason reason) {
     // Remove transaction from memory pool
     {
         LOCK(cs);
         setEntries txToRemove;
         txiter origit = mapTx.find(origTx.GetId());
         if (origit != mapTx.end()) {
             txToRemove.insert(origit);
         } else {
             // When recursively removing but origTx isn't in the mempool be sure
             // to remove any children that are in the pool. This can happen
             // during chain re-orgs if origTx isn't re-accepted into the mempool
             // for any reason.
             for (unsigned int i = 0; i < origTx.vout.size(); i++) {
                 auto it = mapNextTx.find(COutPoint(origTx.GetId(), i));
                 if (it == mapNextTx.end()) continue;
                 txiter nextit = mapTx.find(it->second->GetId());
                 assert(nextit != mapTx.end());
                 txToRemove.insert(nextit);
             }
         }
         setEntries setAllRemoves;
         for (txiter it : txToRemove) {
             CalculateDescendants(it, setAllRemoves);
         }
 
         RemoveStaged(setAllRemoves, false, reason);
     }
 }
 
 void CTxMemPool::removeForReorg(const CCoinsViewCache *pcoins,
                                 unsigned int nMemPoolHeight, int flags) {
     // Remove transactions spending a coinbase which are now immature and
     // no-longer-final transactions
     LOCK(cs);
     setEntries txToRemove;
     for (indexed_transaction_set::const_iterator it = mapTx.begin();
          it != mapTx.end(); it++) {
         const CTransaction &tx = it->GetTx();
         LockPoints lp = it->GetLockPoints();
         bool validLP = TestLockPointValidity(&lp);
 
         auto &config = GetConfig();
         CValidationState state;
         if (!ContextualCheckTransactionForCurrentBlock(
                 config, tx, state, config.GetChainParams().GetConsensus(),
                 flags) ||
             !CheckSequenceLocks(tx, flags, &lp, validLP)) {
             // Note if CheckSequenceLocks fails the LockPoints may still be
             // invalid. So it's critical that we remove the tx and not depend on
             // the LockPoints.
             txToRemove.insert(it);
         } else if (it->GetSpendsCoinbase()) {
             for (const CTxIn &txin : tx.vin) {
                 indexed_transaction_set::const_iterator it2 =
                     mapTx.find(txin.prevout.hash);
                 if (it2 != mapTx.end()) continue;
                 const CCoins *coins = pcoins->AccessCoins(txin.prevout.hash);
                 if (nCheckFrequency != 0) assert(coins);
                 if (!coins || (coins->IsCoinBase() &&
                                ((signed long)nMemPoolHeight) - coins->nHeight <
                                    COINBASE_MATURITY)) {
                     txToRemove.insert(it);
                     break;
                 }
             }
         }
         if (!validLP) {
             mapTx.modify(it, update_lock_points(lp));
         }
     }
     setEntries setAllRemoves;
     for (txiter it : txToRemove) {
         CalculateDescendants(it, setAllRemoves);
     }
     RemoveStaged(setAllRemoves, false, MemPoolRemovalReason::REORG);
 }
 
 void CTxMemPool::removeConflicts(const CTransaction &tx) {
     // Remove transactions which depend on inputs of tx, recursively
     LOCK(cs);
     for (const CTxIn &txin : tx.vin) {
         auto it = mapNextTx.find(txin.prevout);
         if (it != mapNextTx.end()) {
             const CTransaction &txConflict = *it->second;
             if (txConflict != tx) {
                 ClearPrioritisation(txConflict.GetId());
                 removeRecursive(txConflict, MemPoolRemovalReason::CONFLICT);
             }
         }
     }
 }
 
 /**
  * Called when a block is connected. Removes from mempool and updates the miner
  * fee estimator.
  */
 void CTxMemPool::removeForBlock(const std::vector<CTransactionRef> &vtx,
                                 unsigned int nBlockHeight) {
     LOCK(cs);
     std::vector<const CTxMemPoolEntry *> entries;
     for (const auto &tx : vtx) {
         uint256 txid = tx->GetId();
 
         indexed_transaction_set::iterator i = mapTx.find(txid);
         if (i != mapTx.end()) entries.push_back(&*i);
     }
     // Before the txs in the new block have been removed from the mempool,
     // update policy estimates
     minerPolicyEstimator->processBlock(nBlockHeight, entries);
     for (const auto &tx : vtx) {
         txiter it = mapTx.find(tx->GetId());
         if (it != mapTx.end()) {
             setEntries stage;
             stage.insert(it);
             RemoveStaged(stage, true, MemPoolRemovalReason::BLOCK);
         }
         removeConflicts(*tx);
         ClearPrioritisation(tx->GetId());
     }
     lastRollingFeeUpdate = GetTime();
     blockSinceLastRollingFeeBump = true;
 }
 
 void CTxMemPool::_clear() {
     mapLinks.clear();
     mapTx.clear();
     mapNextTx.clear();
     totalTxSize = 0;
     cachedInnerUsage = 0;
     lastRollingFeeUpdate = GetTime();
     blockSinceLastRollingFeeBump = false;
     rollingMinimumFeeRate = 0;
     ++nTransactionsUpdated;
 }
 
 void CTxMemPool::clear() {
     LOCK(cs);
     _clear();
 }
 
 void CTxMemPool::check(const CCoinsViewCache *pcoins) const {
     if (nCheckFrequency == 0) return;
 
     if (GetRand(std::numeric_limits<uint32_t>::max()) >= nCheckFrequency)
         return;
 
     LogPrint("mempool", "Checking mempool with %u transactions and %u inputs\n",
              (unsigned int)mapTx.size(), (unsigned int)mapNextTx.size());
 
     uint64_t checkTotal = 0;
     uint64_t innerUsage = 0;
 
     CCoinsViewCache mempoolDuplicate(const_cast<CCoinsViewCache *>(pcoins));
     const int64_t nSpendHeight = GetSpendHeight(mempoolDuplicate);
 
     LOCK(cs);
     std::list<const CTxMemPoolEntry *> waitingOnDependants;
     for (indexed_transaction_set::const_iterator it = mapTx.begin();
          it != mapTx.end(); it++) {
         unsigned int i = 0;
         checkTotal += it->GetTxSize();
         innerUsage += it->DynamicMemoryUsage();
         const CTransaction &tx = it->GetTx();
         txlinksMap::const_iterator linksiter = mapLinks.find(it);
         assert(linksiter != mapLinks.end());
         const TxLinks &links = linksiter->second;
         innerUsage += memusage::DynamicUsage(links.parents) +
                       memusage::DynamicUsage(links.children);
         bool fDependsWait = false;
         setEntries setParentCheck;
         int64_t parentSizes = 0;
         int64_t parentSigOpCount = 0;
         for (const CTxIn &txin : tx.vin) {
             // Check that every mempool transaction's inputs refer to available
             // coins, or other mempool tx's.
             indexed_transaction_set::const_iterator it2 =
                 mapTx.find(txin.prevout.hash);
             if (it2 != mapTx.end()) {
                 const CTransaction &tx2 = it2->GetTx();
                 assert(tx2.vout.size() > txin.prevout.n &&
                        !tx2.vout[txin.prevout.n].IsNull());
                 fDependsWait = true;
                 if (setParentCheck.insert(it2).second) {
                     parentSizes += it2->GetTxSize();
                     parentSigOpCount += it2->GetSigOpCount();
                 }
             } else {
                 const CCoins *coins = pcoins->AccessCoins(txin.prevout.hash);
                 assert(coins && coins->IsAvailable(txin.prevout.n));
             }
             // Check whether its inputs are marked in mapNextTx.
             auto it3 = mapNextTx.find(txin.prevout);
             assert(it3 != mapNextTx.end());
             assert(it3->first == &txin.prevout);
             assert(it3->second == &tx);
             i++;
         }
         assert(setParentCheck == GetMemPoolParents(it));
         // Verify ancestor state is correct.
         setEntries setAncestors;
         uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
         std::string dummy;
         CalculateMemPoolAncestors(*it, setAncestors, nNoLimit, nNoLimit,
                                   nNoLimit, nNoLimit, dummy);
         uint64_t nCountCheck = setAncestors.size() + 1;
         uint64_t nSizeCheck = it->GetTxSize();
         CAmount nFeesCheck = it->GetModifiedFee();
         int64_t nSigOpCheck = it->GetSigOpCount();
 
         for (txiter ancestorIt : setAncestors) {
             nSizeCheck += ancestorIt->GetTxSize();
             nFeesCheck += ancestorIt->GetModifiedFee();
             nSigOpCheck += ancestorIt->GetSigOpCount();
         }
 
         assert(it->GetCountWithAncestors() == nCountCheck);
         assert(it->GetSizeWithAncestors() == nSizeCheck);
         assert(it->GetSigOpCountWithAncestors() == nSigOpCheck);
         assert(it->GetModFeesWithAncestors() == nFeesCheck);
 
         // Check children against mapNextTx
         CTxMemPool::setEntries setChildrenCheck;
         auto iter = mapNextTx.lower_bound(COutPoint(it->GetTx().GetId(), 0));
         int64_t childSizes = 0;
         for (; iter != mapNextTx.end() &&
                iter->first->hash == it->GetTx().GetId();
              ++iter) {
             txiter childit = mapTx.find(iter->second->GetId());
             assert(childit !=
                    mapTx.end()); // mapNextTx points to in-mempool transactions
             if (setChildrenCheck.insert(childit).second) {
                 childSizes += childit->GetTxSize();
             }
         }
         assert(setChildrenCheck == GetMemPoolChildren(it));
         // Also check to make sure size is greater than sum with immediate
         // children. Just a sanity check, not definitive that this calc is
         // correct...
         assert(it->GetSizeWithDescendants() >= childSizes + it->GetTxSize());
 
         if (fDependsWait)
             waitingOnDependants.push_back(&(*it));
         else {
             CValidationState state;
             bool fCheckResult = tx.IsCoinBase() ||
                                 Consensus::CheckTxInputs(
                                     tx, state, mempoolDuplicate, nSpendHeight);
             assert(fCheckResult);
             UpdateCoins(tx, mempoolDuplicate, 1000000);
         }
     }
     unsigned int stepsSinceLastRemove = 0;
     while (!waitingOnDependants.empty()) {
         const CTxMemPoolEntry *entry = waitingOnDependants.front();
         waitingOnDependants.pop_front();
         CValidationState state;
         if (!mempoolDuplicate.HaveInputs(entry->GetTx())) {
             waitingOnDependants.push_back(entry);
             stepsSinceLastRemove++;
             assert(stepsSinceLastRemove < waitingOnDependants.size());
         } else {
             bool fCheckResult =
                 entry->GetTx().IsCoinBase() ||
                 Consensus::CheckTxInputs(entry->GetTx(), state,
                                          mempoolDuplicate, nSpendHeight);
             assert(fCheckResult);
             UpdateCoins(entry->GetTx(), mempoolDuplicate, 1000000);
             stepsSinceLastRemove = 0;
         }
     }
     for (auto it = mapNextTx.cbegin(); it != mapNextTx.cend(); it++) {
         uint256 txid = it->second->GetId();
         indexed_transaction_set::const_iterator it2 = mapTx.find(txid);
         const CTransaction &tx = it2->GetTx();
         assert(it2 != mapTx.end());
         assert(&tx == it->second);
     }
 
     assert(totalTxSize == checkTotal);
     assert(innerUsage == cachedInnerUsage);
 }
 
 bool CTxMemPool::CompareDepthAndScore(const uint256 &hasha,
                                       const uint256 &hashb) {
     LOCK(cs);
     indexed_transaction_set::const_iterator i = mapTx.find(hasha);
     if (i == mapTx.end()) return false;
     indexed_transaction_set::const_iterator j = mapTx.find(hashb);
     if (j == mapTx.end()) return true;
     uint64_t counta = i->GetCountWithAncestors();
     uint64_t countb = j->GetCountWithAncestors();
     if (counta == countb) {
         return CompareTxMemPoolEntryByScore()(*i, *j);
     }
     return counta < countb;
 }
 
 namespace {
 class DepthAndScoreComparator {
 public:
     bool
     operator()(const CTxMemPool::indexed_transaction_set::const_iterator &a,
                const CTxMemPool::indexed_transaction_set::const_iterator &b) {
         uint64_t counta = a->GetCountWithAncestors();
         uint64_t countb = b->GetCountWithAncestors();
         if (counta == countb) {
             return CompareTxMemPoolEntryByScore()(*a, *b);
         }
         return counta < countb;
     }
 };
 }
 
 std::vector<CTxMemPool::indexed_transaction_set::const_iterator>
 CTxMemPool::GetSortedDepthAndScore() const {
     std::vector<indexed_transaction_set::const_iterator> iters;
     AssertLockHeld(cs);
 
     iters.reserve(mapTx.size());
 
     for (indexed_transaction_set::iterator mi = mapTx.begin();
          mi != mapTx.end(); ++mi) {
         iters.push_back(mi);
     }
     std::sort(iters.begin(), iters.end(), DepthAndScoreComparator());
     return iters;
 }
 
 void CTxMemPool::queryHashes(std::vector<uint256> &vtxid) {
     LOCK(cs);
     auto iters = GetSortedDepthAndScore();
 
     vtxid.clear();
     vtxid.reserve(mapTx.size());
 
     for (auto it : iters) {
         vtxid.push_back(it->GetTx().GetId());
     }
 }
 
 static TxMempoolInfo
 GetInfo(CTxMemPool::indexed_transaction_set::const_iterator it) {
     return TxMempoolInfo{it->GetSharedTx(), it->GetTime(),
                          CFeeRate(it->GetFee(), it->GetTxSize()),
                          it->GetModifiedFee() - it->GetFee()};
 }
 
 std::vector<TxMempoolInfo> CTxMemPool::infoAll() const {
     LOCK(cs);
     auto iters = GetSortedDepthAndScore();
 
     std::vector<TxMempoolInfo> ret;
     ret.reserve(mapTx.size());
     for (auto it : iters) {
         ret.push_back(GetInfo(it));
     }
 
     return ret;
 }
 
 CTransactionRef CTxMemPool::get(const uint256 &txid) const {
     LOCK(cs);
     indexed_transaction_set::const_iterator i = mapTx.find(txid);
     if (i == mapTx.end()) return nullptr;
     return i->GetSharedTx();
 }
 
 TxMempoolInfo CTxMemPool::info(const uint256 &txid) const {
     LOCK(cs);
     indexed_transaction_set::const_iterator i = mapTx.find(txid);
     if (i == mapTx.end()) return TxMempoolInfo();
     return GetInfo(i);
 }
 
 CFeeRate CTxMemPool::estimateFee(int nBlocks) const {
     LOCK(cs);
     return minerPolicyEstimator->estimateFee(nBlocks);
 }
 CFeeRate CTxMemPool::estimateSmartFee(int nBlocks,
                                       int *answerFoundAtBlocks) const {
     LOCK(cs);
     return minerPolicyEstimator->estimateSmartFee(nBlocks, answerFoundAtBlocks,
                                                   *this);
 }
 double CTxMemPool::estimatePriority(int nBlocks) const {
     LOCK(cs);
     return minerPolicyEstimator->estimatePriority(nBlocks);
 }
 double CTxMemPool::estimateSmartPriority(int nBlocks,
                                          int *answerFoundAtBlocks) const {
     LOCK(cs);
     return minerPolicyEstimator->estimateSmartPriority(
         nBlocks, answerFoundAtBlocks, *this);
 }
 
 bool CTxMemPool::WriteFeeEstimates(CAutoFile &fileout) const {
     try {
         LOCK(cs);
         // version required to read: 0.13.99 or later
         fileout << 139900;
         // version that wrote the file
         fileout << CLIENT_VERSION;
         minerPolicyEstimator->Write(fileout);
     } catch (const std::exception &) {
         LogPrintf("CTxMemPool::WriteFeeEstimates(): unable to write policy "
                   "estimator data (non-fatal)\n");
         return false;
     }
     return true;
 }
 
 bool CTxMemPool::ReadFeeEstimates(CAutoFile &filein) {
     try {
         int nVersionRequired, nVersionThatWrote;
         filein >> nVersionRequired >> nVersionThatWrote;
         if (nVersionRequired > CLIENT_VERSION)
             return error("CTxMemPool::ReadFeeEstimates(): up-version (%d) fee "
                          "estimate file",
                          nVersionRequired);
         LOCK(cs);
         minerPolicyEstimator->Read(filein, nVersionThatWrote);
     } catch (const std::exception &) {
         LogPrintf("CTxMemPool::ReadFeeEstimates(): unable to read policy "
                   "estimator data (non-fatal)\n");
         return false;
     }
     return true;
 }
 
 void CTxMemPool::PrioritiseTransaction(const uint256 hash,
                                        const std::string strHash,
                                        double dPriorityDelta,
                                        const CAmount &nFeeDelta) {
     {
         LOCK(cs);
         std::pair<double, CAmount> &deltas = mapDeltas[hash];
         deltas.first += dPriorityDelta;
         deltas.second += nFeeDelta;
         txiter it = mapTx.find(hash);
         if (it != mapTx.end()) {
             mapTx.modify(it, update_fee_delta(deltas.second));
             // Now update all ancestors' modified fees with descendants
             setEntries setAncestors;
             uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
             std::string dummy;
             CalculateMemPoolAncestors(*it, setAncestors, nNoLimit, nNoLimit,
                                       nNoLimit, nNoLimit, dummy, false);
             for (txiter ancestorIt : setAncestors) {
                 mapTx.modify(ancestorIt,
                              update_descendant_state(0, nFeeDelta, 0));
             }
             // Now update all descendants' modified fees with ancestors
             setEntries setDescendants;
             CalculateDescendants(it, setDescendants);
             setDescendants.erase(it);
             for (txiter descendantIt : setDescendants) {
                 mapTx.modify(descendantIt,
                              update_ancestor_state(0, nFeeDelta, 0, 0));
             }
         }
     }
     LogPrintf("PrioritiseTransaction: %s priority += %f, fee += %d\n", strHash,
               dPriorityDelta, FormatMoney(nFeeDelta));
 }
 
 void CTxMemPool::ApplyDeltas(const uint256 hash, double &dPriorityDelta,
                              CAmount &nFeeDelta) const {
     LOCK(cs);
     std::map<uint256, std::pair<double, CAmount>>::const_iterator pos =
         mapDeltas.find(hash);
     if (pos == mapDeltas.end()) return;
     const std::pair<double, CAmount> &deltas = pos->second;
     dPriorityDelta += deltas.first;
     nFeeDelta += deltas.second;
 }
 
 void CTxMemPool::ClearPrioritisation(const uint256 hash) {
     LOCK(cs);
     mapDeltas.erase(hash);
 }
 
 bool CTxMemPool::HasNoInputsOf(const CTransaction &tx) const {
     for (unsigned int i = 0; i < tx.vin.size(); i++)
         if (exists(tx.vin[i].prevout.hash)) return false;
     return true;
 }
 
 CCoinsViewMemPool::CCoinsViewMemPool(CCoinsView *baseIn,
                                      const CTxMemPool &mempoolIn)
     : CCoinsViewBacked(baseIn), mempool(mempoolIn) {}
 
 bool CCoinsViewMemPool::GetCoins(const uint256 &txid, CCoins &coins) const {
     // If an entry in the mempool exists, always return that one, as it's
     // guaranteed to never conflict with the underlying cache, and it cannot
     // have pruned entries (as it contains full) transactions. First checking
     // the underlying cache risks returning a pruned entry instead.
     CTransactionRef ptx = mempool.get(txid);
     if (ptx) {
         coins = CCoins(*ptx, MEMPOOL_HEIGHT);
         return true;
     }
     return (base->GetCoins(txid, coins) && !coins.IsPruned());
 }
 
 bool CCoinsViewMemPool::HaveCoins(const uint256 &txid) const {
-    return mempool.exists(txid) || base->HaveCoins(txid);
+    return mempool.exists(txid) || base->HaveCoins_DONOTUSE(txid);
 }
 
 size_t CTxMemPool::DynamicMemoryUsage() const {
     LOCK(cs);
     // Estimate the overhead of mapTx to be 15 pointers + an allocation, as no
     // exact formula for boost::multi_index_contained is implemented.
     return memusage::MallocUsage(sizeof(CTxMemPoolEntry) +
                                  15 * sizeof(void *)) *
                mapTx.size() +
            memusage::DynamicUsage(mapNextTx) +
            memusage::DynamicUsage(mapDeltas) +
            memusage::DynamicUsage(mapLinks) +
            memusage::DynamicUsage(vTxHashes) + cachedInnerUsage;
 }
 
 void CTxMemPool::RemoveStaged(setEntries &stage, bool updateDescendants,
                               MemPoolRemovalReason reason) {
     AssertLockHeld(cs);
     UpdateForRemoveFromMempool(stage, updateDescendants);
     for (const txiter &it : stage) {
         removeUnchecked(it, reason);
     }
 }
 
 int CTxMemPool::Expire(int64_t time) {
     LOCK(cs);
     indexed_transaction_set::index<entry_time>::type::iterator it =
         mapTx.get<entry_time>().begin();
     setEntries toremove;
     while (it != mapTx.get<entry_time>().end() && it->GetTime() < time) {
         toremove.insert(mapTx.project<0>(it));
         it++;
     }
     setEntries stage;
     for (txiter removeit : toremove) {
         CalculateDescendants(removeit, stage);
     }
     RemoveStaged(stage, false, MemPoolRemovalReason::EXPIRY);
     return stage.size();
 }
 
 bool CTxMemPool::addUnchecked(const uint256 &hash, const CTxMemPoolEntry &entry,
                               bool validFeeEstimate) {
     LOCK(cs);
     setEntries setAncestors;
     uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
     std::string dummy;
     CalculateMemPoolAncestors(entry, setAncestors, nNoLimit, nNoLimit, nNoLimit,
                               nNoLimit, dummy);
     return addUnchecked(hash, entry, setAncestors, validFeeEstimate);
 }
 
 void CTxMemPool::UpdateChild(txiter entry, txiter child, bool add) {
     setEntries s;
     if (add && mapLinks[entry].children.insert(child).second) {
         cachedInnerUsage += memusage::IncrementalDynamicUsage(s);
     } else if (!add && mapLinks[entry].children.erase(child)) {
         cachedInnerUsage -= memusage::IncrementalDynamicUsage(s);
     }
 }
 
 void CTxMemPool::UpdateParent(txiter entry, txiter parent, bool add) {
     setEntries s;
     if (add && mapLinks[entry].parents.insert(parent).second) {
         cachedInnerUsage += memusage::IncrementalDynamicUsage(s);
     } else if (!add && mapLinks[entry].parents.erase(parent)) {
         cachedInnerUsage -= memusage::IncrementalDynamicUsage(s);
     }
 }
 
 const CTxMemPool::setEntries &
 CTxMemPool::GetMemPoolParents(txiter entry) const {
     assert(entry != mapTx.end());
     txlinksMap::const_iterator it = mapLinks.find(entry);
     assert(it != mapLinks.end());
     return it->second.parents;
 }
 
 const CTxMemPool::setEntries &
 CTxMemPool::GetMemPoolChildren(txiter entry) const {
     assert(entry != mapTx.end());
     txlinksMap::const_iterator it = mapLinks.find(entry);
     assert(it != mapLinks.end());
     return it->second.children;
 }
 
 CFeeRate CTxMemPool::GetMinFee(size_t sizelimit) const {
     LOCK(cs);
     if (!blockSinceLastRollingFeeBump || rollingMinimumFeeRate == 0)
         return CFeeRate(rollingMinimumFeeRate);
 
     int64_t time = GetTime();
     if (time > lastRollingFeeUpdate + 10) {
         double halflife = ROLLING_FEE_HALFLIFE;
         if (DynamicMemoryUsage() < sizelimit / 4)
             halflife /= 4;
         else if (DynamicMemoryUsage() < sizelimit / 2)
             halflife /= 2;
 
         rollingMinimumFeeRate =
             rollingMinimumFeeRate /
             pow(2.0, (time - lastRollingFeeUpdate) / halflife);
         lastRollingFeeUpdate = time;
 
         if (rollingMinimumFeeRate <
             (double)incrementalRelayFee.GetFeePerK() / 2) {
             rollingMinimumFeeRate = 0;
             return CFeeRate(0);
         }
     }
     return std::max(CFeeRate(rollingMinimumFeeRate), incrementalRelayFee);
 }
 
 void CTxMemPool::trackPackageRemoved(const CFeeRate &rate) {
     AssertLockHeld(cs);
     if (rate.GetFeePerK() > rollingMinimumFeeRate) {
         rollingMinimumFeeRate = rate.GetFeePerK();
         blockSinceLastRollingFeeBump = false;
     }
 }
 
 void CTxMemPool::TrimToSize(size_t sizelimit,
                             std::vector<uint256> *pvNoSpendsRemaining) {
     LOCK(cs);
 
     unsigned nTxnRemoved = 0;
     CFeeRate maxFeeRateRemoved(0);
     while (!mapTx.empty() && DynamicMemoryUsage() > sizelimit) {
         indexed_transaction_set::index<descendant_score>::type::iterator it =
             mapTx.get<descendant_score>().begin();
 
         // We set the new mempool min fee to the feerate of the removed set,
         // plus the "minimum reasonable fee rate" (ie some value under which we
         // consider txn to have 0 fee). This way, we don't allow txn to enter
         // mempool with feerate equal to txn which were removed with no block in
         // between.
         CFeeRate removed(it->GetModFeesWithDescendants(),
                          it->GetSizeWithDescendants());
         removed += incrementalRelayFee;
         trackPackageRemoved(removed);
         maxFeeRateRemoved = std::max(maxFeeRateRemoved, removed);
 
         setEntries stage;
         CalculateDescendants(mapTx.project<0>(it), stage);
         nTxnRemoved += stage.size();
 
         std::vector<CTransaction> txn;
         if (pvNoSpendsRemaining) {
             txn.reserve(stage.size());
             for (txiter iter : stage) {
                 txn.push_back(iter->GetTx());
             }
         }
         RemoveStaged(stage, false, MemPoolRemovalReason::SIZELIMIT);
         if (pvNoSpendsRemaining) {
             for (const CTransaction &tx : txn) {
                 for (const CTxIn &txin : tx.vin) {
                     if (exists(txin.prevout.hash)) continue;
                     auto iter =
                         mapNextTx.lower_bound(COutPoint(txin.prevout.hash, 0));
                     if (iter == mapNextTx.end() ||
                         iter->first->hash != txin.prevout.hash)
                         pvNoSpendsRemaining->push_back(txin.prevout.hash);
                 }
             }
         }
     }
 
     if (maxFeeRateRemoved > CFeeRate(0))
         LogPrint("mempool",
                  "Removed %u txn, rolling minimum fee bumped to %s\n",
                  nTxnRemoved, maxFeeRateRemoved.ToString());
 }
 
 bool CTxMemPool::TransactionWithinChainLimit(const uint256 &txid,
                                              size_t chainLimit) const {
     LOCK(cs);
     auto it = mapTx.find(txid);
     return it == mapTx.end() || (it->GetCountWithAncestors() < chainLimit &&
                                  it->GetCountWithDescendants() < chainLimit);
 }
diff --git a/src/txmempool.h b/src/txmempool.h
index c537107f7..f80f258ef 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -1,793 +1,794 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_TXMEMPOOL_H
 #define BITCOIN_TXMEMPOOL_H
 
 #include <map>
 #include <memory>
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "amount.h"
 #include "coins.h"
 #include "indirectmap.h"
 #include "primitives/transaction.h"
 #include "random.h"
 #include "sync.h"
 
 #undef foreach
 #include "boost/multi_index/hashed_index.hpp"
 #include "boost/multi_index/ordered_index.hpp"
 #include "boost/multi_index_container.hpp"
 
 #include <boost/signals2/signal.hpp>
 
 class CAutoFile;
 class CBlockIndex;
 
 inline double AllowFreeThreshold() {
     return COIN * 144 / 250;
 }
 
 inline bool AllowFree(double dPriority) {
     // Large (in bytes) low-priority (new, small-coin) transactions need a fee.
     return dPriority > AllowFreeThreshold();
 }
 
 /** Fake height value used in CCoins to signify they are only in the memory pool
  * (since 0.8) */
 static const unsigned int MEMPOOL_HEIGHT = 0x7FFFFFFF;
 
 struct LockPoints {
     // Will be set to the blockchain height and median time past values that
     // would be necessary to satisfy all relative locktime constraints (BIP68)
     // of this tx given our view of block chain history
     int height;
     int64_t time;
     // As long as the current chain descends from the highest height block
     // containing one of the inputs used in the calculation, then the cached
     // values are still valid even after a reorg.
     CBlockIndex *maxInputBlock;
 
     LockPoints() : height(0), time(0), maxInputBlock(nullptr) {}
 };
 
 class CTxMemPool;
 
 /** \class CTxMemPoolEntry
  *
  * CTxMemPoolEntry stores data about the corresponding transaction, as well as
  * data about all in-mempool transactions that depend on the transaction
  * ("descendant" transactions).
  *
  * When a new entry is added to the mempool, we update the descendant state
  * (nCountWithDescendants, nSizeWithDescendants, and nModFeesWithDescendants)
  * for all ancestors of the newly added transaction.
  *
  * If updating the descendant state is skipped, we can mark the entry as
  * "dirty", and set nSizeWithDescendants/nModFeesWithDescendants to equal
  * nTxSize/nFee+feeDelta. (This can potentially happen during a reorg, where we
  * limit the amount of work we're willing to do to avoid consuming too much
  * CPU.)
  */
 
 class CTxMemPoolEntry {
 private:
     CTransactionRef tx;
     //!< Cached to avoid expensive parent-transaction lookups
     CAmount nFee;
     //!< ... and avoid recomputing tx size
     size_t nTxSize;
     //!< ... and modified size for priority
     size_t nModSize;
     //!< ... and total memory usage
     size_t nUsageSize;
     //!< Local time when entering the mempool
     int64_t nTime;
     //!< Priority when entering the mempool
     double entryPriority;
     //!< Chain height when entering the mempool
     unsigned int entryHeight;
     //!< Sum of all txin values that are already in blockchain
     CAmount inChainInputValue;
     //!< keep track of transactions that spend a coinbase
     bool spendsCoinbase;
     //!< Total sigop plus P2SH sigops count
     int64_t sigOpCount;
     //!< Used for determining the priority of the transaction for mining in a
     //! block
     int64_t feeDelta;
     //!< Track the height and time at which tx was final
     LockPoints lockPoints;
 
     // Information about descendants of this transaction that are in the
     // mempool; if we remove this transaction we must remove all of these
     // descendants as well.  if nCountWithDescendants is 0, treat this entry as
     // dirty, and nSizeWithDescendants and nModFeesWithDescendants will not be
     // correct.
     //!< number of descendant transactions
     uint64_t nCountWithDescendants;
     //!< ... and size
     uint64_t nSizeWithDescendants;
     //!< ... and total fees (all including us)
     CAmount nModFeesWithDescendants;
 
     // Analogous statistics for ancestor transactions
     uint64_t nCountWithAncestors;
     uint64_t nSizeWithAncestors;
     CAmount nModFeesWithAncestors;
     int64_t nSigOpCountWithAncestors;
 
 public:
     CTxMemPoolEntry(const CTransactionRef &_tx, const CAmount &_nFee,
                     int64_t _nTime, double _entryPriority,
                     unsigned int _entryHeight, CAmount _inChainInputValue,
                     bool spendsCoinbase, int64_t nSigOpsCost, LockPoints lp);
 
     CTxMemPoolEntry(const CTxMemPoolEntry &other);
 
     const CTransaction &GetTx() const { return *this->tx; }
     CTransactionRef GetSharedTx() const { return this->tx; }
     /**
      * Fast calculation of lower bound of current priority as update from entry
      * priority. Only inputs that were originally in-chain will age.
      */
     double GetPriority(unsigned int currentHeight) const;
     const CAmount &GetFee() const { return nFee; }
     size_t GetTxSize() const { return nTxSize; }
     int64_t GetTime() const { return nTime; }
     unsigned int GetHeight() const { return entryHeight; }
     int64_t GetSigOpCount() const { return sigOpCount; }
     int64_t GetModifiedFee() const { return nFee + feeDelta; }
     size_t DynamicMemoryUsage() const { return nUsageSize; }
     const LockPoints &GetLockPoints() const { return lockPoints; }
 
     // Adjusts the descendant state, if this entry is not dirty.
     void UpdateDescendantState(int64_t modifySize, CAmount modifyFee,
                                int64_t modifyCount);
     // Adjusts the ancestor state
     void UpdateAncestorState(int64_t modifySize, CAmount modifyFee,
                              int64_t modifyCount, int modifySigOps);
     // Updates the fee delta used for mining priority score, and the
     // modified fees with descendants.
     void UpdateFeeDelta(int64_t feeDelta);
     // Update the LockPoints after a reorg
     void UpdateLockPoints(const LockPoints &lp);
 
     uint64_t GetCountWithDescendants() const { return nCountWithDescendants; }
     uint64_t GetSizeWithDescendants() const { return nSizeWithDescendants; }
     CAmount GetModFeesWithDescendants() const {
         return nModFeesWithDescendants;
     }
 
     bool GetSpendsCoinbase() const { return spendsCoinbase; }
 
     uint64_t GetCountWithAncestors() const { return nCountWithAncestors; }
     uint64_t GetSizeWithAncestors() const { return nSizeWithAncestors; }
     CAmount GetModFeesWithAncestors() const { return nModFeesWithAncestors; }
     int64_t GetSigOpCountWithAncestors() const {
         return nSigOpCountWithAncestors;
     }
 
     //!< Index in mempool's vTxHashes
     mutable size_t vTxHashesIdx;
 };
 
 // Helpers for modifying CTxMemPool::mapTx, which is a boost multi_index.
 struct update_descendant_state {
     update_descendant_state(int64_t _modifySize, CAmount _modifyFee,
                             int64_t _modifyCount)
         : modifySize(_modifySize), modifyFee(_modifyFee),
           modifyCount(_modifyCount) {}
 
     void operator()(CTxMemPoolEntry &e) {
         e.UpdateDescendantState(modifySize, modifyFee, modifyCount);
     }
 
 private:
     int64_t modifySize;
     CAmount modifyFee;
     int64_t modifyCount;
 };
 
 struct update_ancestor_state {
     update_ancestor_state(int64_t _modifySize, CAmount _modifyFee,
                           int64_t _modifyCount, int64_t _modifySigOpsCost)
         : modifySize(_modifySize), modifyFee(_modifyFee),
           modifyCount(_modifyCount), modifySigOpsCost(_modifySigOpsCost) {}
 
     void operator()(CTxMemPoolEntry &e) {
         e.UpdateAncestorState(modifySize, modifyFee, modifyCount,
                               modifySigOpsCost);
     }
 
 private:
     int64_t modifySize;
     CAmount modifyFee;
     int64_t modifyCount;
     int64_t modifySigOpsCost;
 };
 
 struct update_fee_delta {
     update_fee_delta(int64_t _feeDelta) : feeDelta(_feeDelta) {}
 
     void operator()(CTxMemPoolEntry &e) { e.UpdateFeeDelta(feeDelta); }
 
 private:
     int64_t feeDelta;
 };
 
 struct update_lock_points {
     update_lock_points(const LockPoints &_lp) : lp(_lp) {}
 
     void operator()(CTxMemPoolEntry &e) { e.UpdateLockPoints(lp); }
 
 private:
     const LockPoints &lp;
 };
 
 // extracts a TxMemPoolEntry's transaction hash
 struct mempoolentry_txid {
     typedef uint256 result_type;
     result_type operator()(const CTxMemPoolEntry &entry) const {
         return entry.GetTx().GetId();
     }
 };
 
 /** \class CompareTxMemPoolEntryByDescendantScore
  *
  *  Sort an entry by max(score/size of entry's tx, score/size with all
  * descendants).
  */
 class CompareTxMemPoolEntryByDescendantScore {
 public:
     bool operator()(const CTxMemPoolEntry &a, const CTxMemPoolEntry &b) {
         bool fUseADescendants = UseDescendantScore(a);
         bool fUseBDescendants = UseDescendantScore(b);
 
         double aModFee = fUseADescendants ? a.GetModFeesWithDescendants()
                                           : a.GetModifiedFee();
         double aSize =
             fUseADescendants ? a.GetSizeWithDescendants() : a.GetTxSize();
 
         double bModFee = fUseBDescendants ? b.GetModFeesWithDescendants()
                                           : b.GetModifiedFee();
         double bSize =
             fUseBDescendants ? b.GetSizeWithDescendants() : b.GetTxSize();
 
         // Avoid division by rewriting (a/b > c/d) as (a*d > c*b).
         double f1 = aModFee * bSize;
         double f2 = aSize * bModFee;
 
         if (f1 == f2) {
             return a.GetTime() >= b.GetTime();
         }
         return f1 < f2;
     }
 
     // Calculate which score to use for an entry (avoiding division).
     bool UseDescendantScore(const CTxMemPoolEntry &a) {
         double f1 = (double)a.GetModifiedFee() * a.GetSizeWithDescendants();
         double f2 = (double)a.GetModFeesWithDescendants() * a.GetTxSize();
         return f2 > f1;
     }
 };
 
 /** \class CompareTxMemPoolEntryByScore
  *
  *  Sort by score of entry ((fee+delta)/size) in descending order
  */
 class CompareTxMemPoolEntryByScore {
 public:
     bool operator()(const CTxMemPoolEntry &a, const CTxMemPoolEntry &b) {
         double f1 = (double)a.GetModifiedFee() * b.GetTxSize();
         double f2 = (double)b.GetModifiedFee() * a.GetTxSize();
         if (f1 == f2) {
             return b.GetTx().GetId() < a.GetTx().GetId();
         }
         return f1 > f2;
     }
 };
 
 class CompareTxMemPoolEntryByEntryTime {
 public:
     bool operator()(const CTxMemPoolEntry &a, const CTxMemPoolEntry &b) {
         return a.GetTime() < b.GetTime();
     }
 };
 
 class CompareTxMemPoolEntryByAncestorFee {
 public:
     bool operator()(const CTxMemPoolEntry &a, const CTxMemPoolEntry &b) {
         double aFees = a.GetModFeesWithAncestors();
         double aSize = a.GetSizeWithAncestors();
 
         double bFees = b.GetModFeesWithAncestors();
         double bSize = b.GetSizeWithAncestors();
 
         // Avoid division by rewriting (a/b > c/d) as (a*d > c*b).
         double f1 = aFees * bSize;
         double f2 = aSize * bFees;
 
         if (f1 == f2) {
             return a.GetTx().GetId() < b.GetTx().GetId();
         }
 
         return f1 > f2;
     }
 };
 
 // Multi_index tag names
 struct descendant_score {};
 struct entry_time {};
 struct mining_score {};
 struct ancestor_score {};
 
 class CBlockPolicyEstimator;
 
 /**
  * Information about a mempool transaction.
  */
 struct TxMempoolInfo {
     /** The transaction itself */
     CTransactionRef tx;
 
     /** Time the transaction entered the mempool. */
     int64_t nTime;
 
     /** Feerate of the transaction. */
     CFeeRate feeRate;
 
     /** The fee delta. */
     int64_t nFeeDelta;
 };
 
 /**
  * Reason why a transaction was removed from the mempool, this is passed to the
  * notification signal.
  */
 enum class MemPoolRemovalReason {
     //! Manually removed or unknown reason
     UNKNOWN = 0,
     //! Expired from mempool
     EXPIRY,
     //! Removed in size limiting
     SIZELIMIT,
     //! Removed for reorganization
     REORG,
     //! Removed for block
     BLOCK,
     //! Removed for conflict with in-block transaction
     CONFLICT,
     //! Removed for replacement
     REPLACED
 };
 
 /**
  * CTxMemPool stores valid-according-to-the-current-best-chain transactions that
  * may be included in the next block.
  *
  * Transactions are added when they are seen on the network (or created by the
  * local node), but not all transactions seen are added to the pool. For
  * example, the following new transactions will not be added to the mempool:
  * - a transaction which doesn't meet the minimum fee requirements.
  * - a new transaction that double-spends an input of a transaction already in
  * the pool where the new transaction does not meet the Replace-By-Fee
  * requirements as defined in BIP 125.
  * - a non-standard transaction.
  *
  * CTxMemPool::mapTx, and CTxMemPoolEntry bookkeeping:
  *
  * mapTx is a boost::multi_index that sorts the mempool on 4 criteria:
  * - transaction hash
  * - feerate [we use max(feerate of tx, feerate of tx with all descendants)]
  * - time in mempool
  * - mining score (feerate modified by any fee deltas from
  * PrioritiseTransaction)
  *
  * Note: the term "descendant" refers to in-mempool transactions that depend on
  * this one, while "ancestor" refers to in-mempool transactions that a given
  * transaction depends on.
  *
  * In order for the feerate sort to remain correct, we must update transactions
  * in the mempool when new descendants arrive. To facilitate this, we track the
  * set of in-mempool direct parents and direct children in mapLinks. Within each
  * CTxMemPoolEntry, we track the size and fees of all descendants.
  *
  * Usually when a new transaction is added to the mempool, it has no in-mempool
  * children (because any such children would be an orphan). So in
  * addUnchecked(), we:
  * - update a new entry's setMemPoolParents to include all in-mempool parents
  * - update the new entry's direct parents to include the new tx as a child
  * - update all ancestors of the transaction to include the new tx's size/fee
  *
  * When a transaction is removed from the mempool, we must:
  * - update all in-mempool parents to not track the tx in setMemPoolChildren
  * - update all ancestors to not include the tx's size/fees in descendant state
  * - update all in-mempool children to not include it as a parent
  *
  * These happen in UpdateForRemoveFromMempool(). (Note that when removing a
  * transaction along with its descendants, we must calculate that set of
  * transactions to be removed before doing the removal, or else the mempool can
  * be in an inconsistent state where it's impossible to walk the ancestors of a
  * transaction.)
  *
  * In the event of a reorg, the assumption that a newly added tx has no
  * in-mempool children is false.  In particular, the mempool is in an
  * inconsistent state while new transactions are being added, because there may
  * be descendant transactions of a tx coming from a disconnected block that are
  * unreachable from just looking at transactions in the mempool (the linking
  * transactions may also be in the disconnected block, waiting to be added).
  * Because of this, there's not much benefit in trying to search for in-mempool
  * children in addUnchecked(). Instead, in the special case of transactions
  * being added from a disconnected block, we require the caller to clean up the
  * state, to account for in-mempool, out-of-block descendants for all the
  * in-block transactions by calling UpdateTransactionsFromBlock(). Note that
  * until this is called, the mempool state is not consistent, and in particular
  * mapLinks may not be correct (and therefore functions like
  * CalculateMemPoolAncestors() and CalculateDescendants() that rely on them to
  * walk the mempool are not generally safe to use).
  *
  * Computational limits:
  *
  * Updating all in-mempool ancestors of a newly added transaction can be slow,
  * if no bound exists on how many in-mempool ancestors there may be.
  * CalculateMemPoolAncestors() takes configurable limits that are designed to
  * prevent these calculations from being too CPU intensive.
  *
  * Adding transactions from a disconnected block can be very time consuming,
  * because we don't have a way to limit the number of in-mempool descendants. To
  * bound CPU processing, we limit the amount of work we're willing to do to
  * properly update the descendant information for a tx being added from a
  * disconnected block. If we would exceed the limit, then we instead mark the
  * entry as "dirty", and set the feerate for sorting purposes to be equal the
  * feerate of the transaction without any descendants.
  */
 class CTxMemPool {
 private:
     //!< Value n means that n times in 2^32 we check.
     uint32_t nCheckFrequency;
     unsigned int nTransactionsUpdated;
     CBlockPolicyEstimator *minerPolicyEstimator;
 
     //!< sum of all mempool tx's virtual sizes.
     uint64_t totalTxSize;
     //!< sum of dynamic memory usage of all the map elements (NOT the maps
     //! themselves)
     uint64_t cachedInnerUsage;
 
     mutable int64_t lastRollingFeeUpdate;
     mutable bool blockSinceLastRollingFeeBump;
     //!< minimum fee to get into the pool, decreases exponentially
     mutable double rollingMinimumFeeRate;
 
     void trackPackageRemoved(const CFeeRate &rate);
 
 public:
     // public only for testing
     static const int ROLLING_FEE_HALFLIFE = 60 * 60 * 12;
 
     typedef boost::multi_index_container<
         CTxMemPoolEntry, boost::multi_index::indexed_by<
                              // sorted by txid
                              boost::multi_index::hashed_unique<
                                  mempoolentry_txid, SaltedTxidHasher>,
                              // sorted by fee rate
                              boost::multi_index::ordered_non_unique<
                                  boost::multi_index::tag<descendant_score>,
                                  boost::multi_index::identity<CTxMemPoolEntry>,
                                  CompareTxMemPoolEntryByDescendantScore>,
                              // sorted by entry time
                              boost::multi_index::ordered_non_unique<
                                  boost::multi_index::tag<entry_time>,
                                  boost::multi_index::identity<CTxMemPoolEntry>,
                                  CompareTxMemPoolEntryByEntryTime>,
                              // sorted by score (for mining prioritization)
                              boost::multi_index::ordered_unique<
                                  boost::multi_index::tag<mining_score>,
                                  boost::multi_index::identity<CTxMemPoolEntry>,
                                  CompareTxMemPoolEntryByScore>,
                              // sorted by fee rate with ancestors
                              boost::multi_index::ordered_non_unique<
                                  boost::multi_index::tag<ancestor_score>,
                                  boost::multi_index::identity<CTxMemPoolEntry>,
                                  CompareTxMemPoolEntryByAncestorFee>>>
         indexed_transaction_set;
 
     mutable CCriticalSection cs;
     indexed_transaction_set mapTx;
 
     typedef indexed_transaction_set::nth_index<0>::type::iterator txiter;
     //!< All tx hashes/entries in mapTx, in random order
     std::vector<std::pair<uint256, txiter>> vTxHashes;
 
     struct CompareIteratorByHash {
         bool operator()(const txiter &a, const txiter &b) const {
             return a->GetTx().GetId() < b->GetTx().GetId();
         }
     };
     typedef std::set<txiter, CompareIteratorByHash> setEntries;
 
     const setEntries &GetMemPoolParents(txiter entry) const;
     const setEntries &GetMemPoolChildren(txiter entry) const;
 
 private:
     typedef std::map<txiter, setEntries, CompareIteratorByHash> cacheMap;
 
     struct TxLinks {
         setEntries parents;
         setEntries children;
     };
 
     typedef std::map<txiter, TxLinks, CompareIteratorByHash> txlinksMap;
     txlinksMap mapLinks;
 
     void UpdateParent(txiter entry, txiter parent, bool add);
     void UpdateChild(txiter entry, txiter child, bool add);
 
     std::vector<indexed_transaction_set::const_iterator>
     GetSortedDepthAndScore() const;
 
 public:
     indirectmap<COutPoint, const CTransaction *> mapNextTx;
     std::map<uint256, std::pair<double, CAmount>> mapDeltas;
 
     /** Create a new CTxMemPool.
      */
     CTxMemPool(const CFeeRate &_minReasonableRelayFee);
     ~CTxMemPool();
 
     /**
      * If sanity-checking is turned on, check makes sure the pool is consistent
      * (does not contain two transactions that spend the same inputs, all inputs
      * are in the mapNextTx array). If sanity-checking is turned off, check does
      * nothing.
      */
     void check(const CCoinsViewCache *pcoins) const;
     void setSanityCheck(double dFrequency = 1.0) {
         nCheckFrequency = dFrequency * 4294967295.0;
     }
 
     // addUnchecked must updated state for all ancestors of a given transaction,
     // to track size/count of descendant transactions. First version of
     // addUnchecked can be used to have it call CalculateMemPoolAncestors(), and
     // then invoke the second version.
     bool addUnchecked(const uint256 &hash, const CTxMemPoolEntry &entry,
                       bool validFeeEstimate = true);
     bool addUnchecked(const uint256 &hash, const CTxMemPoolEntry &entry,
                       setEntries &setAncestors, bool validFeeEstimate = true);
 
     void removeRecursive(
         const CTransaction &tx,
         MemPoolRemovalReason reason = MemPoolRemovalReason::UNKNOWN);
     void removeForReorg(const CCoinsViewCache *pcoins,
                         unsigned int nMemPoolHeight, int flags);
     void removeConflicts(const CTransaction &tx);
     void removeForBlock(const std::vector<CTransactionRef> &vtx,
                         unsigned int nBlockHeight);
 
     void clear();
     // lock free
     void _clear();
     bool CompareDepthAndScore(const uint256 &hasha, const uint256 &hashb);
     void queryHashes(std::vector<uint256> &vtxid);
     void pruneSpent(const uint256 &hash, CCoins &coins);
     unsigned int GetTransactionsUpdated() const;
     void AddTransactionsUpdated(unsigned int n);
     /**
      * Check that none of this transactions inputs are in the mempool, and thus
      * the tx is not dependent on other mempool transactions to be included in a
      * block.
      */
     bool HasNoInputsOf(const CTransaction &tx) const;
 
     /** Affect CreateNewBlock prioritisation of transactions */
     void PrioritiseTransaction(const uint256 hash, const std::string strHash,
                                double dPriorityDelta, const CAmount &nFeeDelta);
     void ApplyDeltas(const uint256 hash, double &dPriorityDelta,
                      CAmount &nFeeDelta) const;
     void ClearPrioritisation(const uint256 hash);
 
 public:
     /**
      * Remove a set of transactions from the mempool. If a transaction is in
      * this set, then all in-mempool descendants must also be in the set, unless
      * this transaction is being removed for being in a block. Set
      * updateDescendants to true when removing a tx that was in a block, so that
      * any in-mempool descendants have their ancestor state updated.
      */
     void
     RemoveStaged(setEntries &stage, bool updateDescendants,
                  MemPoolRemovalReason reason = MemPoolRemovalReason::UNKNOWN);
 
     /**
      * When adding transactions from a disconnected block back to the mempool,
      * new mempool entries may have children in the mempool (which is generally
      * not the case when otherwise adding transactions).
      * UpdateTransactionsFromBlock() will find child transactions and update the
      * descendant state for each transaction in hashesToUpdate (excluding any
      * child transactions present in hashesToUpdate, which are already accounted
      * for).  Note: hashesToUpdate should be the set of transactions from the
      * disconnected block that have been accepted back into the mempool.
      */
     void
     UpdateTransactionsFromBlock(const std::vector<uint256> &hashesToUpdate);
 
     /**
      * Try to calculate all in-mempool ancestors of entry.
      *  (these are all calculated including the tx itself)
      *  limitAncestorCount = max number of ancestors
      *  limitAncestorSize = max size of ancestors
      *  limitDescendantCount = max number of descendants any ancestor can have
      *  limitDescendantSize = max size of descendants any ancestor can have
      *  errString = populated with error reason if any limits are hit
      * fSearchForParents = whether to search a tx's vin for in-mempool parents,
      * or look up parents from mapLinks. Must be true for entries not in the
      * mempool
      */
     bool CalculateMemPoolAncestors(
         const CTxMemPoolEntry &entry, setEntries &setAncestors,
         uint64_t limitAncestorCount, uint64_t limitAncestorSize,
         uint64_t limitDescendantCount, uint64_t limitDescendantSize,
         std::string &errString, bool fSearchForParents = true) const;
 
     /**
      * Populate setDescendants with all in-mempool descendants of hash.
      * Assumes that setDescendants includes all in-mempool descendants of
      * anything already in it.  */
     void CalculateDescendants(txiter it, setEntries &setDescendants);
 
     /**
      * The minimum fee to get into the mempool, which may itself not be enough
      * for larger-sized transactions. The incrementalRelayFee policy variable is
      * used to bound the time it takes the fee rate to go back down all the way
      * to 0. When the feerate would otherwise be half of this, it is set to 0
      * instead.
      */
     CFeeRate GetMinFee(size_t sizelimit) const;
 
     /**
      * Remove transactions from the mempool until its dynamic size is <=
      * sizelimit. pvNoSpendsRemaining, if set, will be populated with the list
      * of transactions which are not in mempool which no longer have any spends
      * in this mempool.
      */
     void TrimToSize(size_t sizelimit,
                     std::vector<uint256> *pvNoSpendsRemaining = nullptr);
 
     /** Expire all transaction (and their dependencies) in the mempool older
      * than time. Return the number of removed transactions. */
     int Expire(int64_t time);
 
     /** Returns false if the transaction is in the mempool and not within the
      * chain limit specified. */
     bool TransactionWithinChainLimit(const uint256 &txid,
                                      size_t chainLimit) const;
 
     unsigned long size() {
         LOCK(cs);
         return mapTx.size();
     }
 
     uint64_t GetTotalTxSize() {
         LOCK(cs);
         return totalTxSize;
     }
 
     bool exists(uint256 hash) const {
         LOCK(cs);
         return (mapTx.count(hash) != 0);
     }
 
     CTransactionRef get(const uint256 &hash) const;
     TxMempoolInfo info(const uint256 &hash) const;
     std::vector<TxMempoolInfo> infoAll() const;
 
     /**
      * Estimate fee rate needed to get into the next nBlocks. If no answer can
      * be given at nBlocks, return an estimate at the lowest number of blocks
      * where one can be given.
      */
     CFeeRate estimateSmartFee(int nBlocks,
                               int *answerFoundAtBlocks = nullptr) const;
 
     /** Estimate fee rate needed to get into the next nBlocks */
     CFeeRate estimateFee(int nBlocks) const;
 
     /**
      * Estimate priority needed to get into the next nBlocks. If no answer can
      * be given at nBlocks, return an estimate at the lowest number of blocks
      * where one can be given.
      */
     double estimateSmartPriority(int nBlocks,
                                  int *answerFoundAtBlocks = nullptr) const;
 
     /** Estimate priority needed to get into the next nBlocks */
     double estimatePriority(int nBlocks) const;
 
     /** Write/Read estimates to disk */
     bool WriteFeeEstimates(CAutoFile &fileout) const;
     bool ReadFeeEstimates(CAutoFile &filein);
 
     size_t DynamicMemoryUsage() const;
 
     boost::signals2::signal<void(CTransactionRef)> NotifyEntryAdded;
     boost::signals2::signal<void(CTransactionRef, MemPoolRemovalReason)>
         NotifyEntryRemoved;
 
 private:
     /**
      * UpdateForDescendants is used by UpdateTransactionsFromBlock to update the
      * descendants for a single transaction that has been added to the mempool
      * but may have child transactions in the mempool, eg during a chain reorg.
      * setExclude is the set of descendant transactions in the mempool that must
      * not be accounted for (because any descendants in setExclude were added to
      * the mempool after the transaction being updated and hence their state is
      * already reflected in the parent state).
      *
      * cachedDescendants will be updated with the descendants of the transaction
      * being updated, so that future invocations don't need to walk the same
      * transaction again, if encountered in another transaction chain.
      */
     void UpdateForDescendants(txiter updateIt, cacheMap &cachedDescendants,
                               const std::set<uint256> &setExclude);
     /** Update ancestors of hash to add/remove it as a descendant transaction.
      */
     void UpdateAncestorsOf(bool add, txiter hash, setEntries &setAncestors);
     /** Set ancestor state for an entry */
     void UpdateEntryForAncestors(txiter it, const setEntries &setAncestors);
     /**
      * For each transaction being removed, update ancestors and any direct
      * children. If updateDescendants is true, then also update in-mempool
      * descendants' ancestor state.
      */
     void UpdateForRemoveFromMempool(const setEntries &entriesToRemove,
                                     bool updateDescendants);
     /** Sever link between specified transaction and direct children. */
     void UpdateChildrenForRemoval(txiter entry);
 
     /**
      * Before calling removeUnchecked for a given transaction,
      * UpdateForRemoveFromMempool must be called on the entire (dependent) set
      * of transactions being removed at the same time. We use each
      * CTxMemPoolEntry's setMemPoolParents in order to walk ancestors of a given
      * transaction that is removed, so we can't remove intermediate transactions
      * in a chain before we've updated all the state for the removal.
      */
     void removeUnchecked(txiter entry, MemPoolRemovalReason reason =
                                            MemPoolRemovalReason::UNKNOWN);
 };
 
 /**
  * CCoinsView that brings transactions from a memorypool into view.
  * It does not check for spendings by memory pool transactions.
  */
 class CCoinsViewMemPool : public CCoinsViewBacked {
 protected:
     const CTxMemPool &mempool;
 
+    bool HaveCoins(const uint256 &txid) const;
+
 public:
     CCoinsViewMemPool(CCoinsView *baseIn, const CTxMemPool &mempoolIn);
     bool GetCoins(const uint256 &txid, CCoins &coins) const;
-    bool HaveCoins(const uint256 &txid) const;
 };
 
 // We want to sort transactions by coin age priority
 typedef std::pair<double, CTxMemPool::txiter> TxCoinAgePriority;
 
 struct TxCoinAgePriorityCompare {
     bool operator()(const TxCoinAgePriority &a, const TxCoinAgePriority &b) {
         if (a.first == b.first) {
             // Reverse order to make sort less than
             return CompareTxMemPoolEntryByScore()(*(b.second), *(a.second));
         }
         return a.first < b.first;
     }
 };
 
 #endif // BITCOIN_TXMEMPOOL_H
diff --git a/src/validation.cpp b/src/validation.cpp
index cb41117af..67cb182df 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1,4804 +1,4807 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Copyright (c) 2017 The Bitcoin developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include "validation.h"
 
 #include "arith_uint256.h"
 #include "chainparams.h"
 #include "checkpoints.h"
 #include "checkqueue.h"
 #include "config.h"
 #include "consensus/consensus.h"
 #include "consensus/merkle.h"
 #include "consensus/validation.h"
 #include "hash.h"
 #include "init.h"
 #include "policy/fees.h"
 #include "policy/policy.h"
 #include "pow.h"
 #include "primitives/block.h"
 #include "primitives/transaction.h"
 #include "random.h"
 #include "script/script.h"
 #include "script/sigcache.h"
 #include "script/standard.h"
 #include "timedata.h"
 #include "tinyformat.h"
 #include "txdb.h"
 #include "txmempool.h"
 #include "ui_interface.h"
 #include "undo.h"
 #include "util.h"
 #include "utilmoneystr.h"
 #include "utilstrencodings.h"
 #include "validationinterface.h"
 #include "versionbits.h"
 #include "warnings.h"
 
 #include <atomic>
 #include <sstream>
 
 #include <boost/algorithm/string/join.hpp>
 #include <boost/algorithm/string/replace.hpp>
 #include <boost/filesystem.hpp>
 #include <boost/filesystem/fstream.hpp>
 #include <boost/math/distributions/poisson.hpp>
 #include <boost/range/adaptor/reversed.hpp>
 #include <boost/thread.hpp>
 
 #if defined(NDEBUG)
 #error "Bitcoin cannot be compiled without assertions."
 #endif
 
 /**
  * Global state
  */
 
 CCriticalSection cs_main;
 
 BlockMap mapBlockIndex;
 CChain chainActive;
 CBlockIndex *pindexBestHeader = nullptr;
 CWaitableCriticalSection csBestBlock;
 CConditionVariable cvBlockChange;
 int nScriptCheckThreads = 0;
 std::atomic_bool fImporting(false);
 bool fReindex = false;
 bool fTxIndex = false;
 bool fHavePruned = false;
 bool fPruneMode = false;
 bool fIsBareMultisigStd = DEFAULT_PERMIT_BAREMULTISIG;
 bool fRequireStandard = true;
 bool fCheckBlockIndex = false;
 bool fCheckpointsEnabled = DEFAULT_CHECKPOINTS_ENABLED;
 size_t nCoinCacheUsage = 5000 * 300;
 uint64_t nPruneTarget = 0;
 int64_t nMaxTipAge = DEFAULT_MAX_TIP_AGE;
 
 uint256 hashAssumeValid;
 
 CFeeRate minRelayTxFee = CFeeRate(DEFAULT_MIN_RELAY_TX_FEE);
 CAmount maxTxFee = DEFAULT_TRANSACTION_MAXFEE;
 
 CTxMemPool mempool(::minRelayTxFee);
 
 static void CheckBlockIndex(const Consensus::Params &consensusParams);
 
 /** Constant stuff for coinbase transactions we create: */
 CScript COINBASE_FLAGS;
 
 const std::string strMessageMagic = "Bitcoin Signed Message:\n";
 
 // Internal stuff
 namespace {
 
 struct CBlockIndexWorkComparator {
     bool operator()(CBlockIndex *pa, CBlockIndex *pb) const {
         // First sort by most total work, ...
         if (pa->nChainWork > pb->nChainWork) return false;
         if (pa->nChainWork < pb->nChainWork) return true;
 
         // ... then by earliest time received, ...
         if (pa->nSequenceId < pb->nSequenceId) return false;
         if (pa->nSequenceId > pb->nSequenceId) return true;
 
         // Use pointer address as tie breaker (should only happen with blocks
         // loaded from disk, as those all have id 0).
         if (pa < pb) return false;
         if (pa > pb) return true;
 
         // Identical blocks.
         return false;
     }
 };
 
 CBlockIndex *pindexBestInvalid;
 
 /**
  * The set of all CBlockIndex entries with BLOCK_VALID_TRANSACTIONS (for itself
  * and all ancestors) and as good as our current tip or better. Entries may be
  * failed, though, and pruning nodes may be missing the data for the block.
  */
 std::set<CBlockIndex *, CBlockIndexWorkComparator> setBlockIndexCandidates;
 /**
  * All pairs A->B, where A (or one of its ancestors) misses transactions, but B
  * has transactions. Pruned nodes may have entries where B is missing data.
  */
 std::multimap<CBlockIndex *, CBlockIndex *> mapBlocksUnlinked;
 
 CCriticalSection cs_LastBlockFile;
 std::vector<CBlockFileInfo> vinfoBlockFile;
 int nLastBlockFile = 0;
 /**
  * Global flag to indicate we should check to see if there are block/undo files
  * that should be deleted. Set on startup or if we allocate more file space when
  * we're in prune mode.
  */
 bool fCheckForPruning = false;
 
 /**
  * Every received block is assigned a unique and increasing identifier, so we
  * know which one to give priority in case of a fork.
  */
 CCriticalSection cs_nBlockSequenceId;
 /** Blocks loaded from disk are assigned id 0, so start the counter at 1. */
 int32_t nBlockSequenceId = 1;
 /** Decreasing counter (used by subsequent preciousblock calls). */
 int32_t nBlockReverseSequenceId = -1;
 /** chainwork for the last block that preciousblock has been applied to. */
 arith_uint256 nLastPreciousChainwork = 0;
 
 /** Dirty block index entries. */
 std::set<CBlockIndex *> setDirtyBlockIndex;
 
 /** Dirty block file entries. */
 std::set<int> setDirtyFileInfo;
 } // anon namespace
 
 /* Use this class to start tracking transactions that are removed from the
  * mempool and pass all those transactions through SyncTransaction when the
  * object goes out of scope. This is currently only used to call SyncTransaction
  * on conflicts removed from the mempool during block connection.  Applied in
  * ActivateBestChain around ActivateBestStep which in turn calls:
  * ConnectTip->removeForBlock->removeConflicts
  */
 class MemPoolConflictRemovalTracker {
 private:
     std::vector<CTransactionRef> conflictedTxs;
     CTxMemPool &pool;
 
 public:
     MemPoolConflictRemovalTracker(CTxMemPool &_pool) : pool(_pool) {
         pool.NotifyEntryRemoved.connect(boost::bind(
             &MemPoolConflictRemovalTracker::NotifyEntryRemoved, this, _1, _2));
     }
 
     void NotifyEntryRemoved(CTransactionRef txRemoved,
                             MemPoolRemovalReason reason) {
         if (reason == MemPoolRemovalReason::CONFLICT) {
             conflictedTxs.push_back(txRemoved);
         }
     }
 
     ~MemPoolConflictRemovalTracker() {
         pool.NotifyEntryRemoved.disconnect(boost::bind(
             &MemPoolConflictRemovalTracker::NotifyEntryRemoved, this, _1, _2));
         for (const auto &tx : conflictedTxs) {
             GetMainSignals().SyncTransaction(
                 *tx, nullptr, CMainSignals::SYNC_TRANSACTION_NOT_IN_BLOCK);
         }
         conflictedTxs.clear();
     }
 };
 
 CBlockIndex *FindForkInGlobalIndex(const CChain &chain,
                                    const CBlockLocator &locator) {
     // Find the first block the caller has in the main chain
     for (const uint256 &hash : locator.vHave) {
         BlockMap::iterator mi = mapBlockIndex.find(hash);
         if (mi != mapBlockIndex.end()) {
             CBlockIndex *pindex = (*mi).second;
             if (chain.Contains(pindex)) return pindex;
             if (pindex->GetAncestor(chain.Height()) == chain.Tip()) {
                 return chain.Tip();
             }
         }
     }
     return chain.Genesis();
 }
 
 CCoinsViewCache *pcoinsTip = nullptr;
 CBlockTreeDB *pblocktree = nullptr;
 
 enum FlushStateMode {
     FLUSH_STATE_NONE,
     FLUSH_STATE_IF_NEEDED,
     FLUSH_STATE_PERIODIC,
     FLUSH_STATE_ALWAYS
 };
 
 // See definition for documentation
 bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode,
                              int nManualPruneHeight = 0);
 void FindFilesToPruneManual(std::set<int> &setFilesToPrune,
                             int nManualPruneHeight);
 
 static bool IsFinalTx(const CTransaction &tx, int nBlockHeight,
                       int64_t nBlockTime) {
     if (tx.nLockTime == 0) {
         return true;
     }
 
     int64_t lockTime = tx.nLockTime;
     int64_t lockTimeLimit =
         (lockTime < LOCKTIME_THRESHOLD) ? nBlockHeight : nBlockTime;
     if (lockTime < lockTimeLimit) {
         return true;
     }
 
     for (const auto &txin : tx.vin) {
         if (txin.nSequence != CTxIn::SEQUENCE_FINAL) {
             return false;
         }
     }
     return true;
 }
 
 /**
  * Calculates the block height and previous block's median time past at
  * which the transaction will be considered final in the context of BIP 68.
  * Also removes from the vector of input heights any entries which did not
  * correspond to sequence locked inputs as they do not affect the calculation.
  */
 static std::pair<int, int64_t>
 CalculateSequenceLocks(const CTransaction &tx, int flags,
                        std::vector<int> *prevHeights,
                        const CBlockIndex &block) {
     assert(prevHeights->size() == tx.vin.size());
 
     // Will be set to the equivalent height- and time-based nLockTime
     // values that would be necessary to satisfy all relative lock-
     // time constraints given our view of block chain history.
     // The semantics of nLockTime are the last invalid height/time, so
     // use -1 to have the effect of any height or time being valid.
     int nMinHeight = -1;
     int64_t nMinTime = -1;
 
     // tx.nVersion is signed integer so requires cast to unsigned otherwise
     // we would be doing a signed comparison and half the range of nVersion
     // wouldn't support BIP 68.
     bool fEnforceBIP68 = static_cast<uint32_t>(tx.nVersion) >= 2 &&
                          flags & LOCKTIME_VERIFY_SEQUENCE;
 
     // Do not enforce sequence numbers as a relative lock time
     // unless we have been instructed to
     if (!fEnforceBIP68) {
         return std::make_pair(nMinHeight, nMinTime);
     }
 
     for (size_t txinIndex = 0; txinIndex < tx.vin.size(); txinIndex++) {
         const CTxIn &txin = tx.vin[txinIndex];
 
         // Sequence numbers with the most significant bit set are not
         // treated as relative lock-times, nor are they given any
         // consensus-enforced meaning at this point.
         if (txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_DISABLE_FLAG) {
             // The height of this input is not relevant for sequence locks
             (*prevHeights)[txinIndex] = 0;
             continue;
         }
 
         int nCoinHeight = (*prevHeights)[txinIndex];
 
         if (txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG) {
             int64_t nCoinTime = block.GetAncestor(std::max(nCoinHeight - 1, 0))
                                     ->GetMedianTimePast();
             // NOTE: Subtract 1 to maintain nLockTime semantics.
             // BIP 68 relative lock times have the semantics of calculating the
             // first block or time at which the transaction would be valid. When
             // calculating the effective block time or height for the entire
             // transaction, we switch to using the semantics of nLockTime which
             // is the last invalid block time or height. Thus we subtract 1 from
             // the calculated time or height.
 
             // Time-based relative lock-times are measured from the smallest
             // allowed timestamp of the block containing the txout being spent,
             // which is the median time past of the block prior.
             nMinTime = std::max(
                 nMinTime,
                 nCoinTime +
                     (int64_t)((txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_MASK)
                               << CTxIn::SEQUENCE_LOCKTIME_GRANULARITY) -
                     1);
         } else {
             nMinHeight = std::max(
                 nMinHeight,
                 nCoinHeight +
                     (int)(txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_MASK) - 1);
         }
     }
 
     return std::make_pair(nMinHeight, nMinTime);
 }
 
 static bool EvaluateSequenceLocks(const CBlockIndex &block,
                                   std::pair<int, int64_t> lockPair) {
     assert(block.pprev);
     int64_t nBlockTime = block.pprev->GetMedianTimePast();
     if (lockPair.first >= block.nHeight || lockPair.second >= nBlockTime)
         return false;
 
     return true;
 }
 
 bool SequenceLocks(const CTransaction &tx, int flags,
                    std::vector<int> *prevHeights, const CBlockIndex &block) {
     return EvaluateSequenceLocks(
         block, CalculateSequenceLocks(tx, flags, prevHeights, block));
 }
 
 bool TestLockPointValidity(const LockPoints *lp) {
     AssertLockHeld(cs_main);
     assert(lp);
     // If there are relative lock times then the maxInputBlock will be set
     // If there are no relative lock times, the LockPoints don't depend on the
     // chain
     if (lp->maxInputBlock) {
         // Check whether chainActive is an extension of the block at which the
         // LockPoints
         // calculation was valid.  If not LockPoints are no longer valid
         if (!chainActive.Contains(lp->maxInputBlock)) {
             return false;
         }
     }
 
     // LockPoints still valid
     return true;
 }
 
 bool CheckSequenceLocks(const CTransaction &tx, int flags, LockPoints *lp,
                         bool useExistingLockPoints) {
     AssertLockHeld(cs_main);
     AssertLockHeld(mempool.cs);
 
     CBlockIndex *tip = chainActive.Tip();
     CBlockIndex index;
     index.pprev = tip;
     // CheckSequenceLocks() uses chainActive.Height()+1 to evaluate
     // height based locks because when SequenceLocks() is called within
     // ConnectBlock(), the height of the block *being*
     // evaluated is what is used.
     // Thus if we want to know if a transaction can be part of the
     // *next* block, we need to use one more than chainActive.Height()
     index.nHeight = tip->nHeight + 1;
 
     std::pair<int, int64_t> lockPair;
     if (useExistingLockPoints) {
         assert(lp);
         lockPair.first = lp->height;
         lockPair.second = lp->time;
     } else {
         // pcoinsTip contains the UTXO set for chainActive.Tip()
         CCoinsViewMemPool viewMemPool(pcoinsTip, mempool);
         std::vector<int> prevheights;
         prevheights.resize(tx.vin.size());
         for (size_t txinIndex = 0; txinIndex < tx.vin.size(); txinIndex++) {
             const CTxIn &txin = tx.vin[txinIndex];
             CCoins coins;
             if (!viewMemPool.GetCoins(txin.prevout.hash, coins)) {
                 return error("%s: Missing input", __func__);
             }
             if (coins.nHeight == MEMPOOL_HEIGHT) {
                 // Assume all mempool transaction confirm in the next block
                 prevheights[txinIndex] = tip->nHeight + 1;
             } else {
                 prevheights[txinIndex] = coins.nHeight;
             }
         }
         lockPair = CalculateSequenceLocks(tx, flags, &prevheights, index);
         if (lp) {
             lp->height = lockPair.first;
             lp->time = lockPair.second;
             // Also store the hash of the block with the highest height of all
             // the blocks which have sequence locked prevouts. This hash needs
             // to still be on the chain for these LockPoint calculations to be
             // valid.
             // Note: It is impossible to correctly calculate a maxInputBlock if
             // any of the sequence locked inputs depend on unconfirmed txs,
             // except in the special case where the relative lock time/height is
             // 0, which is equivalent to no sequence lock. Since we assume input
             // height of tip+1 for mempool txs and test the resulting lockPair
             // from CalculateSequenceLocks against tip+1. We know
             // EvaluateSequenceLocks will fail if there was a non-zero sequence
             // lock on a mempool input, so we can use the return value of
             // CheckSequenceLocks to indicate the LockPoints validity
             int maxInputHeight = 0;
             for (int height : prevheights) {
                 // Can ignore mempool inputs since we'll fail if they had
                 // non-zero locks
                 if (height != tip->nHeight + 1) {
                     maxInputHeight = std::max(maxInputHeight, height);
                 }
             }
             lp->maxInputBlock = tip->GetAncestor(maxInputHeight);
         }
     }
     return EvaluateSequenceLocks(index, lockPair);
 }
 
 uint64_t GetSigOpCountWithoutP2SH(const CTransaction &tx) {
     uint64_t nSigOps = 0;
     for (const auto &txin : tx.vin) {
         nSigOps += txin.scriptSig.GetSigOpCount(false);
     }
     for (const auto &txout : tx.vout) {
         nSigOps += txout.scriptPubKey.GetSigOpCount(false);
     }
     return nSigOps;
 }
 
 uint64_t GetP2SHSigOpCount(const CTransaction &tx,
                            const CCoinsViewCache &inputs) {
     if (tx.IsCoinBase()) return 0;
 
     uint64_t nSigOps = 0;
     for (unsigned int i = 0; i < tx.vin.size(); i++) {
         const CTxOut &prevout = inputs.GetOutputFor(tx.vin[i]);
         if (prevout.scriptPubKey.IsPayToScriptHash())
             nSigOps += prevout.scriptPubKey.GetSigOpCount(tx.vin[i].scriptSig);
     }
     return nSigOps;
 }
 
 uint64_t GetTransactionSigOpCount(const CTransaction &tx,
                                   const CCoinsViewCache &inputs, int flags) {
     uint64_t nSigOps = GetSigOpCountWithoutP2SH(tx);
 
     if (tx.IsCoinBase()) return nSigOps;
 
     if (flags & SCRIPT_VERIFY_P2SH) {
         nSigOps += GetP2SHSigOpCount(tx, inputs);
     }
 
     return nSigOps;
 }
 
 static bool CheckTransactionCommon(const CTransaction &tx,
                                    CValidationState &state,
                                    bool fCheckDuplicateInputs) {
     // Basic checks that don't depend on any context
     if (tx.vin.empty()) {
         return state.DoS(10, false, REJECT_INVALID, "bad-txns-vin-empty");
     }
 
     if (tx.vout.empty()) {
         return state.DoS(10, false, REJECT_INVALID, "bad-txns-vout-empty");
     }
 
     // Size limit
     if (::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION) > MAX_TX_SIZE) {
         return state.DoS(100, false, REJECT_INVALID, "bad-txns-oversize");
     }
 
     // Check for negative or overflow output values
     CAmount nValueOut = 0;
     for (const auto &txout : tx.vout) {
         if (txout.nValue < 0) {
             return state.DoS(100, false, REJECT_INVALID,
                              "bad-txns-vout-negative");
         }
 
         if (txout.nValue > MAX_MONEY) {
             return state.DoS(100, false, REJECT_INVALID,
                              "bad-txns-vout-toolarge");
         }
 
         nValueOut += txout.nValue;
         if (!MoneyRange(nValueOut)) {
             return state.DoS(100, false, REJECT_INVALID,
                              "bad-txns-txouttotal-toolarge");
         }
     }
 
     if (GetSigOpCountWithoutP2SH(tx) > MAX_TX_SIGOPS_COUNT) {
         return state.DoS(100, false, REJECT_INVALID, "bad-txn-sigops");
     }
 
     // Check for duplicate inputs - note that this check is slow so we skip it
     // in CheckBlock
     if (fCheckDuplicateInputs) {
         std::set<COutPoint> vInOutPoints;
         for (const auto &txin : tx.vin) {
             if (!vInOutPoints.insert(txin.prevout).second) {
                 return state.DoS(100, false, REJECT_INVALID,
                                  "bad-txns-inputs-duplicate");
             }
         }
     }
 
     return true;
 }
 
 bool CheckCoinbase(const CTransaction &tx, CValidationState &state,
                    bool fCheckDuplicateInputs) {
     if (!tx.IsCoinBase()) {
         return state.DoS(100, false, REJECT_INVALID, "bad-cb-missing", false,
                          "first tx is not coinbase");
     }
 
     if (!CheckTransactionCommon(tx, state, fCheckDuplicateInputs)) {
         // CheckTransactionCommon fill in the state.
         return false;
     }
 
     if (tx.vin[0].scriptSig.size() < 2 || tx.vin[0].scriptSig.size() > 100) {
         return state.DoS(100, false, REJECT_INVALID, "bad-cb-length");
     }
 
     return true;
 }
 
 bool CheckRegularTransaction(const CTransaction &tx, CValidationState &state,
                              bool fCheckDuplicateInputs) {
     if (tx.IsCoinBase()) {
         return state.DoS(100, false, REJECT_INVALID, "bad-tx-coinbase");
     }
 
     if (!CheckTransactionCommon(tx, state, fCheckDuplicateInputs)) {
         // CheckTransactionCommon fill in the state.
         return false;
     }
 
     for (const auto &txin : tx.vin) {
         if (txin.prevout.IsNull()) {
             return state.DoS(10, false, REJECT_INVALID,
                              "bad-txns-prevout-null");
         }
     }
 
     return true;
 }
 
 void LimitMempoolSize(CTxMemPool &pool, size_t limit, unsigned long age) {
     int expired = pool.Expire(GetTime() - age);
     if (expired != 0)
         LogPrint("mempool", "Expired %i transactions from the memory pool\n",
                  expired);
 
     std::vector<uint256> vNoSpendsRemaining;
     pool.TrimToSize(limit, &vNoSpendsRemaining);
     for (const uint256 &removed : vNoSpendsRemaining) {
         pcoinsTip->Uncache(removed);
     }
 }
 
 /** Convert CValidationState to a human-readable message for logging */
 std::string FormatStateMessage(const CValidationState &state) {
     return strprintf(
         "%s%s (code %i)", state.GetRejectReason(),
         state.GetDebugMessage().empty() ? "" : ", " + state.GetDebugMessage(),
         state.GetRejectCode());
 }
 
 static bool IsCurrentForFeeEstimation() {
     AssertLockHeld(cs_main);
     if (IsInitialBlockDownload()) return false;
     if (chainActive.Tip()->GetBlockTime() <
         (GetTime() - MAX_FEE_ESTIMATION_TIP_AGE))
         return false;
     if (chainActive.Height() < pindexBestHeader->nHeight - 1) return false;
     return true;
 }
 
 static bool IsUAHFenabled(const Config &config, int64_t nMedianTimePast) {
     return nMedianTimePast >= config.GetUAHFStartTime();
 }
 
 bool IsUAHFenabled(const Config &config, const CBlockIndex *pindexPrev) {
     if (pindexPrev == nullptr) {
         return false;
     }
 
     return IsUAHFenabled(config, pindexPrev->GetMedianTimePast());
 }
 
 bool IsUAHFenabledForCurrentBlock(const Config &config) {
     AssertLockHeld(cs_main);
     return IsUAHFenabled(config, chainActive.Tip());
 }
 
 static bool AcceptToMemoryPoolWorker(
     const Config &config, CTxMemPool &pool, CValidationState &state,
     const CTransactionRef &ptx, bool fLimitFree, bool *pfMissingInputs,
     int64_t nAcceptTime, std::list<CTransactionRef> *plTxnReplaced,
     bool fOverrideMempoolLimit, const CAmount &nAbsurdFee,
     std::vector<uint256> &vHashTxnToUncache) {
     AssertLockHeld(cs_main);
 
     const CTransaction &tx = *ptx;
     const uint256 txid = tx.GetId();
     if (pfMissingInputs) {
         *pfMissingInputs = false;
     }
 
     // Coinbase is only valid in a block, not as a loose transaction.
     if (!CheckRegularTransaction(tx, state, true)) {
         // state filled in by CheckRegularTransaction.
         return false;
     }
 
     // Rather not work on nonstandard transactions (unless -testnet/-regtest)
     std::string reason;
     if (fRequireStandard && !IsStandardTx(tx, reason)) {
         return state.DoS(0, false, REJECT_NONSTANDARD, reason);
     }
 
     // Only accept nLockTime-using transactions that can be mined in the next
     // block; we don't want our mempool filled up with transactions that can't
     // be mined yet.
     if (!ContextualCheckTransactionForCurrentBlock(
             config, tx, state, config.GetChainParams().GetConsensus(),
             STANDARD_LOCKTIME_VERIFY_FLAGS)) {
         return state.DoS(0, false, REJECT_NONSTANDARD, "non-final");
     }
 
     // Is it already in the memory pool?
     if (pool.exists(txid)) {
         return state.Invalid(false, REJECT_ALREADY_KNOWN,
                              "txn-already-in-mempool");
     }
 
     // Check for conflicts with in-memory transactions
     {
         // Protect pool.mapNextTx
         LOCK(pool.cs);
         for (const CTxIn &txin : tx.vin) {
             auto itConflicting = pool.mapNextTx.find(txin.prevout);
             if (itConflicting != pool.mapNextTx.end()) {
                 // Disable replacement feature for good
                 return state.Invalid(false, REJECT_CONFLICT,
                                      "txn-mempool-conflict");
             }
         }
     }
 
     {
         CCoinsView dummy;
         CCoinsViewCache view(&dummy);
 
         CAmount nValueIn = 0;
         LockPoints lp;
         {
             LOCK(pool.cs);
             CCoinsViewMemPool viewMemPool(pcoinsTip, pool);
             view.SetBackend(viewMemPool);
 
             // Do we already have it?
-            bool fHadTxInCache = pcoinsTip->HaveCoinsInCache(txid);
-            if (view.HaveCoins(txid)) {
-                if (!fHadTxInCache) {
-                    vHashTxnToUncache.push_back(txid);
-                }
+            for (size_t out = 0; out < tx.vout.size(); out++) {
+                COutPoint outpoint(txid, out);
+                bool fHadTxInCache = pcoinsTip->HaveCoinInCache(outpoint);
+                if (view.HaveCoin(outpoint)) {
+                    if (!fHadTxInCache) {
+                        vHashTxnToUncache.push_back(txid);
+                    }
 
-                return state.Invalid(false, REJECT_ALREADY_KNOWN,
-                                     "txn-already-known");
+                    return state.Invalid(false, REJECT_ALREADY_KNOWN,
+                                         "txn-already-known");
+                }
             }
 
             // Do all inputs exist? Note that this does not check for the
             // presence of actual outputs (see the next check for that), and
             // only helps with filling in pfMissingInputs (to determine missing
             // vs spent).
             for (const CTxIn txin : tx.vin) {
-                if (!pcoinsTip->HaveCoinsInCache(txin.prevout.hash)) {
+                if (!pcoinsTip->HaveCoinInCache(txin.prevout)) {
                     vHashTxnToUncache.push_back(txin.prevout.hash);
                 }
 
-                if (!view.HaveCoins(txin.prevout.hash)) {
+                if (!view.HaveCoin(txin.prevout)) {
                     if (pfMissingInputs) {
                         *pfMissingInputs = true;
                     }
 
                     // fMissingInputs and !state.IsInvalid() is used to detect
                     // this condition, don't set state.Invalid()
                     return false;
                 }
             }
 
             // Are the actual inputs available?
             if (!view.HaveInputs(tx)) {
                 return state.Invalid(false, REJECT_DUPLICATE,
                                      "bad-txns-inputs-spent");
             }
 
             // Bring the best block into scope.
             view.GetBestBlock();
 
             nValueIn = view.GetValueIn(tx);
 
             // We have all inputs cached now, so switch back to dummy, so we
             // don't need to keep lock on mempool.
             view.SetBackend(dummy);
 
             // Only accept BIP68 sequence locked transactions that can be mined
             // in the next block; we don't want our mempool filled up with
             // transactions that can't be mined yet. Must keep pool.cs for this
             // unless we change CheckSequenceLocks to take a CoinsViewCache
             // instead of create its own.
             if (!CheckSequenceLocks(tx, STANDARD_LOCKTIME_VERIFY_FLAGS, &lp)) {
                 return state.DoS(0, false, REJECT_NONSTANDARD,
                                  "non-BIP68-final");
             }
         }
 
         // Check for non-standard pay-to-script-hash in inputs
         if (fRequireStandard && !AreInputsStandard(tx, view)) {
             return state.Invalid(false, REJECT_NONSTANDARD,
                                  "bad-txns-nonstandard-inputs");
         }
 
         int64_t nSigOpsCount =
             GetTransactionSigOpCount(tx, view, STANDARD_SCRIPT_VERIFY_FLAGS);
 
         CAmount nValueOut = tx.GetValueOut();
         CAmount nFees = nValueIn - nValueOut;
         // nModifiedFees includes any fee deltas from PrioritiseTransaction
         CAmount nModifiedFees = nFees;
         double nPriorityDummy = 0;
         pool.ApplyDeltas(txid, nPriorityDummy, nModifiedFees);
 
         CAmount inChainInputValue;
         double dPriority =
             view.GetPriority(tx, chainActive.Height(), inChainInputValue);
 
         // Keep track of transactions that spend a coinbase, which we re-scan
         // during reorgs to ensure COINBASE_MATURITY is still met.
         bool fSpendsCoinbase = false;
         for (const CTxIn &txin : tx.vin) {
             const CCoins *coins = view.AccessCoins(txin.prevout.hash);
             if (coins->IsCoinBase()) {
                 fSpendsCoinbase = true;
                 break;
             }
         }
 
         CTxMemPoolEntry entry(ptx, nFees, nAcceptTime, dPriority,
                               chainActive.Height(), inChainInputValue,
                               fSpendsCoinbase, nSigOpsCount, lp);
         unsigned int nSize = entry.GetTxSize();
 
         // Check that the transaction doesn't have an excessive number of
         // sigops, making it impossible to mine. Since the coinbase transaction
         // itself can contain sigops MAX_STANDARD_TX_SIGOPS is less than
         // MAX_BLOCK_SIGOPS_PER_MB; we still consider this an invalid rather
         // than merely non-standard transaction.
         if (nSigOpsCount > MAX_STANDARD_TX_SIGOPS) {
             return state.DoS(0, false, REJECT_NONSTANDARD,
                              "bad-txns-too-many-sigops", false,
                              strprintf("%d", nSigOpsCount));
         }
 
         CAmount mempoolRejectFee =
             pool.GetMinFee(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) *
                            1000000)
                 .GetFee(nSize);
         if (mempoolRejectFee > 0 && nModifiedFees < mempoolRejectFee) {
             return state.DoS(0, false, REJECT_INSUFFICIENTFEE,
                              "mempool min fee not met", false,
                              strprintf("%d < %d", nFees, mempoolRejectFee));
         } else if (GetBoolArg("-relaypriority", DEFAULT_RELAYPRIORITY) &&
                    nModifiedFees < ::minRelayTxFee.GetFee(nSize) &&
                    !AllowFree(entry.GetPriority(chainActive.Height() + 1))) {
             // Require that free transactions have sufficient priority to be
             // mined in the next block.
             return state.DoS(0, false, REJECT_INSUFFICIENTFEE,
                              "insufficient priority");
         }
 
         // Continuously rate-limit free (really, very-low-fee) transactions.
         // This mitigates 'penny-flooding' -- sending thousands of free
         // transactions just to be annoying or make others' transactions take
         // longer to confirm.
         if (fLimitFree && nModifiedFees < ::minRelayTxFee.GetFee(nSize)) {
             static CCriticalSection csFreeLimiter;
             static double dFreeCount;
             static int64_t nLastTime;
             int64_t nNow = GetTime();
 
             LOCK(csFreeLimiter);
 
             // Use an exponentially decaying ~10-minute window:
             dFreeCount *= pow(1.0 - 1.0 / 600.0, (double)(nNow - nLastTime));
             nLastTime = nNow;
             // -limitfreerelay unit is thousand-bytes-per-minute
             // At default rate it would take over a month to fill 1GB
             if (dFreeCount + nSize >=
                 GetArg("-limitfreerelay", DEFAULT_LIMITFREERELAY) * 10 * 1000) {
                 return state.DoS(0, false, REJECT_INSUFFICIENTFEE,
                                  "rate limited free transaction");
             }
 
             LogPrint("mempool", "Rate limit dFreeCount: %g => %g\n", dFreeCount,
                      dFreeCount + nSize);
             dFreeCount += nSize;
         }
 
         if (nAbsurdFee && nFees > nAbsurdFee) {
             return state.Invalid(false, REJECT_HIGHFEE, "absurdly-high-fee",
                                  strprintf("%d > %d", nFees, nAbsurdFee));
         }
 
         // Calculate in-mempool ancestors, up to a limit.
         CTxMemPool::setEntries setAncestors;
         size_t nLimitAncestors =
             GetArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT);
         size_t nLimitAncestorSize =
             GetArg("-limitancestorsize", DEFAULT_ANCESTOR_SIZE_LIMIT) * 1000;
         size_t nLimitDescendants =
             GetArg("-limitdescendantcount", DEFAULT_DESCENDANT_LIMIT);
         size_t nLimitDescendantSize =
             GetArg("-limitdescendantsize", DEFAULT_DESCENDANT_SIZE_LIMIT) *
             1000;
         std::string errString;
         if (!pool.CalculateMemPoolAncestors(
                 entry, setAncestors, nLimitAncestors, nLimitAncestorSize,
                 nLimitDescendants, nLimitDescendantSize, errString)) {
             return state.DoS(0, false, REJECT_NONSTANDARD,
                              "too-long-mempool-chain", false, errString);
         }
 
         unsigned int scriptVerifyFlags = STANDARD_SCRIPT_VERIFY_FLAGS;
         if (!Params().RequireStandard()) {
             scriptVerifyFlags =
                 GetArg("-promiscuousmempoolflags", scriptVerifyFlags);
         }
 
         if (IsUAHFenabledForCurrentBlock(config)) {
             scriptVerifyFlags |= SCRIPT_ENABLE_SIGHASH_FORKID;
         }
 
         // Check against previous transactions. This is done last to help
         // prevent CPU exhaustion denial-of-service attacks.
         PrecomputedTransactionData txdata(tx);
         if (!CheckInputs(tx, state, view, true, scriptVerifyFlags, true,
                          txdata)) {
             // State filled in by CheckInputs.
             return false;
         }
 
         // Check again against just the consensus-critical mandatory script
         // verification flags, in case of bugs in the standard flags that cause
         // transactions to pass as valid when they're actually invalid. For
         // instance the STRICTENC flag was incorrectly allowing certain
         // CHECKSIG NOT scripts to pass, even though they were invalid.
         //
         // There is a similar check in CreateNewBlock() to prevent creating
         // invalid blocks, however allowing such transactions into the mempool
         // can be exploited as a DoS attack.
         //
         // SCRIPT_ENABLE_SIGHASH_FORKID is also added as to ensure we do not
         // filter out transactions using the antireplay feature.
         if (!CheckInputs(tx, state, view, true,
                          MANDATORY_SCRIPT_VERIFY_FLAGS |
                              SCRIPT_ENABLE_SIGHASH_FORKID,
                          true, txdata)) {
             return error("%s: BUG! PLEASE REPORT THIS! ConnectInputs failed "
                          "against MANDATORY but not STANDARD flags %s, %s",
                          __func__, txid.ToString(), FormatStateMessage(state));
         }
 
         // This transaction should only count for fee estimation if
         // the node is not behind and it is not dependent on any other
         // transactions in the mempool.
         bool validForFeeEstimation =
             IsCurrentForFeeEstimation() && pool.HasNoInputsOf(tx);
 
         // Store transaction in memory.
         pool.addUnchecked(txid, entry, setAncestors, validForFeeEstimation);
 
         // Trim mempool and check if tx was trimmed.
         if (!fOverrideMempoolLimit) {
             LimitMempoolSize(
                 pool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000,
                 GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
             if (!pool.exists(txid))
                 return state.DoS(0, false, REJECT_INSUFFICIENTFEE,
                                  "mempool full");
         }
     }
 
     GetMainSignals().SyncTransaction(
         tx, nullptr, CMainSignals::SYNC_TRANSACTION_NOT_IN_BLOCK);
 
     return true;
 }
 
 bool AcceptToMemoryPoolWithTime(const Config &config, CTxMemPool &pool,
                                 CValidationState &state,
                                 const CTransactionRef &tx, bool fLimitFree,
                                 bool *pfMissingInputs, int64_t nAcceptTime,
                                 std::list<CTransactionRef> *plTxnReplaced,
                                 bool fOverrideMempoolLimit,
                                 const CAmount nAbsurdFee) {
     std::vector<uint256> vHashTxToUncache;
     bool res = AcceptToMemoryPoolWorker(
         config, pool, state, tx, fLimitFree, pfMissingInputs, nAcceptTime,
         plTxnReplaced, fOverrideMempoolLimit, nAbsurdFee, vHashTxToUncache);
     if (!res) {
         for (const uint256 &txid : vHashTxToUncache) {
             pcoinsTip->Uncache(txid);
         }
     }
     // After we've (potentially) uncached entries, ensure our coins cache is
     // still within its size limits
     CValidationState stateDummy;
     FlushStateToDisk(stateDummy, FLUSH_STATE_PERIODIC);
     return res;
 }
 
 bool AcceptToMemoryPool(const Config &config, CTxMemPool &pool,
                         CValidationState &state, const CTransactionRef &tx,
                         bool fLimitFree, bool *pfMissingInputs,
                         std::list<CTransactionRef> *plTxnReplaced,
                         bool fOverrideMempoolLimit, const CAmount nAbsurdFee) {
     return AcceptToMemoryPoolWithTime(config, pool, state, tx, fLimitFree,
                                       pfMissingInputs, GetTime(), plTxnReplaced,
                                       fOverrideMempoolLimit, nAbsurdFee);
 }
 
 /** Return transaction in txOut, and if it was found inside a block, its hash is
  * placed in hashBlock */
 bool GetTransaction(const Config &config, const uint256 &txid,
                     CTransactionRef &txOut, uint256 &hashBlock,
                     bool fAllowSlow) {
     CBlockIndex *pindexSlow = nullptr;
 
     LOCK(cs_main);
 
     CTransactionRef ptx = mempool.get(txid);
     if (ptx) {
         txOut = ptx;
         return true;
     }
 
     if (fTxIndex) {
         CDiskTxPos postx;
         if (pblocktree->ReadTxIndex(txid, postx)) {
             CAutoFile file(OpenBlockFile(postx, true), SER_DISK,
                            CLIENT_VERSION);
             if (file.IsNull())
                 return error("%s: OpenBlockFile failed", __func__);
             CBlockHeader header;
             try {
                 file >> header;
                 fseek(file.Get(), postx.nTxOffset, SEEK_CUR);
                 file >> txOut;
             } catch (const std::exception &e) {
                 return error("%s: Deserialize or I/O error - %s", __func__,
                              e.what());
             }
             hashBlock = header.GetHash();
             if (txOut->GetId() != txid)
                 return error("%s: txid mismatch", __func__);
             return true;
         }
     }
 
     // use coin database to locate block that contains transaction, and scan it
     if (fAllowSlow) {
         int nHeight = -1;
         {
             const CCoinsViewCache &view = *pcoinsTip;
             const CCoins *coins = view.AccessCoins(txid);
             if (coins) nHeight = coins->nHeight;
         }
         if (nHeight > 0) pindexSlow = chainActive[nHeight];
     }
 
     if (pindexSlow) {
         auto &params = config.GetChainParams().GetConsensus();
 
         CBlock block;
         if (ReadBlockFromDisk(block, pindexSlow, params)) {
             for (const auto &tx : block.vtx) {
                 if (tx->GetId() == txid) {
                     txOut = tx;
                     hashBlock = pindexSlow->GetBlockHash();
                     return true;
                 }
             }
         }
     }
 
     return false;
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // CBlock and CBlockIndex
 //
 
 bool WriteBlockToDisk(const CBlock &block, CDiskBlockPos &pos,
                       const CMessageHeader::MessageStartChars &messageStart) {
     // Open history file to append
     CAutoFile fileout(OpenBlockFile(pos), SER_DISK, CLIENT_VERSION);
     if (fileout.IsNull())
         return error("WriteBlockToDisk: OpenBlockFile failed");
 
     // Write index header
     unsigned int nSize = GetSerializeSize(fileout, block);
     fileout << FLATDATA(messageStart) << nSize;
 
     // Write block
     long fileOutPos = ftell(fileout.Get());
     if (fileOutPos < 0) return error("WriteBlockToDisk: ftell failed");
     pos.nPos = (unsigned int)fileOutPos;
     fileout << block;
 
     return true;
 }
 
 bool ReadBlockFromDisk(CBlock &block, const CDiskBlockPos &pos,
                        const Consensus::Params &consensusParams) {
     block.SetNull();
 
     // Open history file to read
     CAutoFile filein(OpenBlockFile(pos, true), SER_DISK, CLIENT_VERSION);
     if (filein.IsNull())
         return error("ReadBlockFromDisk: OpenBlockFile failed for %s",
                      pos.ToString());
 
     // Read block
     try {
         filein >> block;
     } catch (const std::exception &e) {
         return error("%s: Deserialize or I/O error - %s at %s", __func__,
                      e.what(), pos.ToString());
     }
 
     // Check the header
     if (!CheckProofOfWork(block.GetHash(), block.nBits, consensusParams))
         return error("ReadBlockFromDisk: Errors in block header at %s",
                      pos.ToString());
 
     return true;
 }
 
 bool ReadBlockFromDisk(CBlock &block, const CBlockIndex *pindex,
                        const Consensus::Params &consensusParams) {
     if (!ReadBlockFromDisk(block, pindex->GetBlockPos(), consensusParams))
         return false;
     if (block.GetHash() != pindex->GetBlockHash())
         return error("ReadBlockFromDisk(CBlock&, CBlockIndex*): GetHash() "
                      "doesn't match index for %s at %s",
                      pindex->ToString(), pindex->GetBlockPos().ToString());
     return true;
 }
 
 CAmount GetBlockSubsidy(int nHeight, const Consensus::Params &consensusParams) {
     int halvings = nHeight / consensusParams.nSubsidyHalvingInterval;
     // Force block reward to zero when right shift is undefined.
     if (halvings >= 64) return 0;
 
     CAmount nSubsidy = 50 * COIN;
     // Subsidy is cut in half every 210,000 blocks which will occur
     // approximately every 4 years.
     nSubsidy >>= halvings;
     return nSubsidy;
 }
 
 bool IsInitialBlockDownload() {
     const CChainParams &chainParams = Params();
 
     // Once this function has returned false, it must remain false.
     static std::atomic<bool> latchToFalse{false};
     // Optimization: pre-test latch before taking the lock.
     if (latchToFalse.load(std::memory_order_relaxed)) return false;
 
     LOCK(cs_main);
     if (latchToFalse.load(std::memory_order_relaxed)) return false;
     if (fImporting || fReindex) return true;
     if (chainActive.Tip() == nullptr) return true;
     if (chainActive.Tip()->nChainWork <
         UintToArith256(chainParams.GetConsensus().nMinimumChainWork))
         return true;
     if (chainActive.Tip()->GetBlockTime() < (GetTime() - nMaxTipAge))
         return true;
     latchToFalse.store(true, std::memory_order_relaxed);
     return false;
 }
 
 CBlockIndex *pindexBestForkTip = nullptr, *pindexBestForkBase = nullptr;
 
 static void AlertNotify(const std::string &strMessage) {
     uiInterface.NotifyAlertChanged();
     std::string strCmd = GetArg("-alertnotify", "");
     if (strCmd.empty()) return;
 
     // Alert text should be plain ascii coming from a trusted source, but to be
     // safe we first strip anything not in safeChars, then add single quotes
     // around the whole string before passing it to the shell:
     std::string singleQuote("'");
     std::string safeStatus = SanitizeString(strMessage);
     safeStatus = singleQuote + safeStatus + singleQuote;
     boost::replace_all(strCmd, "%s", safeStatus);
 
     boost::thread t(runCommand, strCmd); // thread runs free
 }
 
 void CheckForkWarningConditions() {
     AssertLockHeld(cs_main);
     // Before we get past initial download, we cannot reliably alert about forks
     // (we assume we don't get stuck on a fork before finishing our initial
     // sync)
     if (IsInitialBlockDownload()) return;
 
     // If our best fork is no longer within 72 blocks (+/- 12 hours if no one
     // mines it) of our head, drop it
     if (pindexBestForkTip &&
         chainActive.Height() - pindexBestForkTip->nHeight >= 72)
         pindexBestForkTip = nullptr;
 
     if (pindexBestForkTip ||
         (pindexBestInvalid &&
          pindexBestInvalid->nChainWork >
              chainActive.Tip()->nChainWork +
                  (GetBlockProof(*chainActive.Tip()) * 6))) {
         if (!GetfLargeWorkForkFound() && pindexBestForkBase) {
             std::string warning =
                 std::string("'Warning: Large-work fork detected, forking after "
                             "block ") +
                 pindexBestForkBase->phashBlock->ToString() + std::string("'");
             AlertNotify(warning);
         }
         if (pindexBestForkTip && pindexBestForkBase) {
             LogPrintf("%s: Warning: Large valid fork found\n  forking the "
                       "chain at height %d (%s)\n  lasting to height %d "
                       "(%s).\nChain state database corruption likely.\n",
                       __func__, pindexBestForkBase->nHeight,
                       pindexBestForkBase->phashBlock->ToString(),
                       pindexBestForkTip->nHeight,
                       pindexBestForkTip->phashBlock->ToString());
             SetfLargeWorkForkFound(true);
         } else {
             LogPrintf("%s: Warning: Found invalid chain at least ~6 blocks "
                       "longer than our best chain.\nChain state database "
                       "corruption likely.\n",
                       __func__);
             SetfLargeWorkInvalidChainFound(true);
         }
     } else {
         SetfLargeWorkForkFound(false);
         SetfLargeWorkInvalidChainFound(false);
     }
 }
 
 void CheckForkWarningConditionsOnNewFork(CBlockIndex *pindexNewForkTip) {
     AssertLockHeld(cs_main);
     // If we are on a fork that is sufficiently large, set a warning flag
     CBlockIndex *pfork = pindexNewForkTip;
     CBlockIndex *plonger = chainActive.Tip();
     while (pfork && pfork != plonger) {
         while (plonger && plonger->nHeight > pfork->nHeight)
             plonger = plonger->pprev;
         if (pfork == plonger) break;
         pfork = pfork->pprev;
     }
 
     // We define a condition where we should warn the user about as a fork of at
     // least 7 blocks with a tip within 72 blocks (+/- 12 hours if no one mines
     // it) of ours. We use 7 blocks rather arbitrarily as it represents just
     // under 10% of sustained network hash rate operating on the fork, or a
     // chain that is entirely longer than ours and invalid (note that this
     // should be detected by both). We define it this way because it allows us
     // to only store the highest fork tip (+ base) which meets the 7-block
     // condition and from this always have the most-likely-to-cause-warning fork
     if (pfork && (!pindexBestForkTip ||
                   (pindexBestForkTip &&
                    pindexNewForkTip->nHeight > pindexBestForkTip->nHeight)) &&
         pindexNewForkTip->nChainWork - pfork->nChainWork >
             (GetBlockProof(*pfork) * 7) &&
         chainActive.Height() - pindexNewForkTip->nHeight < 72) {
         pindexBestForkTip = pindexNewForkTip;
         pindexBestForkBase = pfork;
     }
 
     CheckForkWarningConditions();
 }
 
 static void InvalidChainFound(CBlockIndex *pindexNew) {
     if (!pindexBestInvalid ||
         pindexNew->nChainWork > pindexBestInvalid->nChainWork)
         pindexBestInvalid = pindexNew;
 
     LogPrintf(
         "%s: invalid block=%s  height=%d  log2_work=%.8g  date=%s\n", __func__,
         pindexNew->GetBlockHash().ToString(), pindexNew->nHeight,
         log(pindexNew->nChainWork.getdouble()) / log(2.0),
         DateTimeStrFormat("%Y-%m-%d %H:%M:%S", pindexNew->GetBlockTime()));
     CBlockIndex *tip = chainActive.Tip();
     assert(tip);
     LogPrintf("%s:  current best=%s  height=%d  log2_work=%.8g  date=%s\n",
               __func__, tip->GetBlockHash().ToString(), chainActive.Height(),
               log(tip->nChainWork.getdouble()) / log(2.0),
               DateTimeStrFormat("%Y-%m-%d %H:%M:%S", tip->GetBlockTime()));
     CheckForkWarningConditions();
 }
 
 static void InvalidBlockFound(CBlockIndex *pindex,
                               const CValidationState &state) {
     if (!state.CorruptionPossible()) {
         pindex->nStatus |= BLOCK_FAILED_VALID;
         setDirtyBlockIndex.insert(pindex);
         setBlockIndexCandidates.erase(pindex);
         InvalidChainFound(pindex);
     }
 }
 
 void UpdateCoins(const CTransaction &tx, CCoinsViewCache &inputs,
                  CTxUndo &txundo, int nHeight) {
     // mark inputs spent
     if (!tx.IsCoinBase()) {
         txundo.vprevout.reserve(tx.vin.size());
         for (const CTxIn &txin : tx.vin) {
             CCoinsModifier coins = inputs.ModifyCoins(txin.prevout.hash);
             unsigned nPos = txin.prevout.n;
 
             if (nPos >= coins->vout.size() || coins->vout[nPos].IsNull())
                 assert(false);
             // mark an outpoint spent, and construct undo information
             txundo.vprevout.push_back(CTxInUndo(coins->vout[nPos]));
             coins->Spend(nPos);
             if (coins->vout.size() == 0) {
                 CTxInUndo &undo = txundo.vprevout.back();
                 undo.nHeight = coins->nHeight;
                 undo.fCoinBase = coins->fCoinBase;
                 undo.nVersion = coins->nVersion;
             }
         }
     }
     // add outputs
     inputs.ModifyNewCoins(tx.GetId(), tx.IsCoinBase())->FromTx(tx, nHeight);
 }
 
 void UpdateCoins(const CTransaction &tx, CCoinsViewCache &inputs, int nHeight) {
     CTxUndo txundo;
     UpdateCoins(tx, inputs, txundo, nHeight);
 }
 
 bool CScriptCheck::operator()() {
     const CScript &scriptSig = ptxTo->vin[nIn].scriptSig;
     if (!VerifyScript(scriptSig, scriptPubKey, nFlags,
                       CachingTransactionSignatureChecker(ptxTo, nIn, amount,
                                                          cacheStore, txdata),
                       &error)) {
         return false;
     }
     return true;
 }
 
 int GetSpendHeight(const CCoinsViewCache &inputs) {
     LOCK(cs_main);
     CBlockIndex *pindexPrev = mapBlockIndex.find(inputs.GetBestBlock())->second;
     return pindexPrev->nHeight + 1;
 }
 
 namespace Consensus {
 bool CheckTxInputs(const CTransaction &tx, CValidationState &state,
                    const CCoinsViewCache &inputs, int nSpendHeight) {
     // This doesn't trigger the DoS code on purpose; if it did, it would make it
     // easier
     // for an attacker to attempt to split the network.
     if (!inputs.HaveInputs(tx))
         return state.Invalid(false, 0, "", "Inputs unavailable");
 
     CAmount nValueIn = 0;
     CAmount nFees = 0;
     for (unsigned int i = 0; i < tx.vin.size(); i++) {
         const COutPoint &prevout = tx.vin[i].prevout;
         const CCoins *coins = inputs.AccessCoins(prevout.hash);
         assert(coins);
 
         // If prev is coinbase, check that it's matured
         if (coins->IsCoinBase()) {
             if (nSpendHeight - coins->nHeight < COINBASE_MATURITY)
                 return state.Invalid(
                     false, REJECT_INVALID,
                     "bad-txns-premature-spend-of-coinbase",
                     strprintf("tried to spend coinbase at depth %d",
                               nSpendHeight - coins->nHeight));
         }
 
         // Check for negative or overflow input values
         nValueIn += coins->vout[prevout.n].nValue;
         if (!MoneyRange(coins->vout[prevout.n].nValue) || !MoneyRange(nValueIn))
             return state.DoS(100, false, REJECT_INVALID,
                              "bad-txns-inputvalues-outofrange");
     }
 
     if (nValueIn < tx.GetValueOut())
         return state.DoS(100, false, REJECT_INVALID, "bad-txns-in-belowout",
                          false, strprintf("value in (%s) < value out (%s)",
                                           FormatMoney(nValueIn),
                                           FormatMoney(tx.GetValueOut())));
 
     // Tally transaction fees
     CAmount nTxFee = nValueIn - tx.GetValueOut();
     if (nTxFee < 0)
         return state.DoS(100, false, REJECT_INVALID, "bad-txns-fee-negative");
     nFees += nTxFee;
     if (!MoneyRange(nFees))
         return state.DoS(100, false, REJECT_INVALID, "bad-txns-fee-outofrange");
     return true;
 }
 } // namespace Consensus
 
 bool CheckInputs(const CTransaction &tx, CValidationState &state,
                  const CCoinsViewCache &inputs, bool fScriptChecks,
                  unsigned int flags, bool cacheStore,
                  const PrecomputedTransactionData &txdata,
                  std::vector<CScriptCheck> *pvChecks) {
     assert(!tx.IsCoinBase());
 
     if (!Consensus::CheckTxInputs(tx, state, inputs, GetSpendHeight(inputs))) {
         return false;
     }
 
     if (pvChecks) {
         pvChecks->reserve(tx.vin.size());
     }
 
     // The first loop above does all the inexpensive checks. Only if ALL inputs
     // pass do we perform expensive ECDSA signature checks. Helps prevent CPU
     // exhaustion attacks.
 
     // Skip script verification when connecting blocks under the assumedvalid
     // block. Assuming the assumedvalid block is valid this is safe because
     // block merkle hashes are still computed and checked, of course, if an
     // assumed valid block is invalid due to false scriptSigs this optimization
     // would allow an invalid chain to be accepted.
     if (!fScriptChecks) {
         return true;
     }
 
     for (unsigned int i = 0; i < tx.vin.size(); i++) {
         const COutPoint &prevout = tx.vin[i].prevout;
         const CCoins *coins = inputs.AccessCoins(prevout.hash);
         assert(coins);
 
         // Verify signature
         CScriptCheck check(*coins, tx, i, flags, cacheStore, txdata);
         if (pvChecks) {
             pvChecks->push_back(std::move(check));
         } else if (!check()) {
             if (flags & STANDARD_NOT_MANDATORY_VERIFY_FLAGS) {
                 // Check whether the failure was caused by a non-mandatory
                 // script verification check, such as non-standard DER encodings
                 // or non-null dummy arguments; if so, don't trigger DoS
                 // protection to avoid splitting the network between upgraded
                 // and non-upgraded nodes.
                 CScriptCheck check2(
                     *coins, tx, i, flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS,
                     cacheStore, txdata);
                 if (check2()) {
                     return state.Invalid(
                         false, REJECT_NONSTANDARD,
                         strprintf("non-mandatory-script-verify-flag (%s)",
                                   ScriptErrorString(check.GetScriptError())));
                 }
             }
 
             // Failures of other flags indicate a transaction that is invalid in
             // new blocks, e.g. a invalid P2SH. We DoS ban such nodes as they
             // are not following the protocol. That said during an upgrade
             // careful thought should be taken as to the correct behavior - we
             // may want to continue peering with non-upgraded nodes even after
             // soft-fork super-majority signaling has occurred.
             return state.DoS(
                 100, false, REJECT_INVALID,
                 strprintf("mandatory-script-verify-flag-failed (%s)",
                           ScriptErrorString(check.GetScriptError())));
         }
     }
 
     return true;
 }
 
 namespace {
 
 bool UndoWriteToDisk(const CBlockUndo &blockundo, CDiskBlockPos &pos,
                      const uint256 &hashBlock,
                      const CMessageHeader::MessageStartChars &messageStart) {
     // Open history file to append
     CAutoFile fileout(OpenUndoFile(pos), SER_DISK, CLIENT_VERSION);
     if (fileout.IsNull()) return error("%s: OpenUndoFile failed", __func__);
 
     // Write index header
     unsigned int nSize = GetSerializeSize(fileout, blockundo);
     fileout << FLATDATA(messageStart) << nSize;
 
     // Write undo data
     long fileOutPos = ftell(fileout.Get());
     if (fileOutPos < 0) return error("%s: ftell failed", __func__);
     pos.nPos = (unsigned int)fileOutPos;
     fileout << blockundo;
 
     // calculate & write checksum
     CHashWriter hasher(SER_GETHASH, PROTOCOL_VERSION);
     hasher << hashBlock;
     hasher << blockundo;
     fileout << hasher.GetHash();
 
     return true;
 }
 
 bool UndoReadFromDisk(CBlockUndo &blockundo, const CDiskBlockPos &pos,
                       const uint256 &hashBlock) {
     // Open history file to read
     CAutoFile filein(OpenUndoFile(pos, true), SER_DISK, CLIENT_VERSION);
     if (filein.IsNull()) return error("%s: OpenUndoFile failed", __func__);
 
     // Read block
     uint256 hashChecksum;
     try {
         filein >> blockundo;
         filein >> hashChecksum;
     } catch (const std::exception &e) {
         return error("%s: Deserialize or I/O error - %s", __func__, e.what());
     }
 
     // Verify checksum
     CHashWriter hasher(SER_GETHASH, PROTOCOL_VERSION);
     hasher << hashBlock;
     hasher << blockundo;
     if (hashChecksum != hasher.GetHash())
         return error("%s: Checksum mismatch", __func__);
 
     return true;
 }
 
 /** Abort with a message */
 bool AbortNode(const std::string &strMessage,
                const std::string &userMessage = "") {
     SetMiscWarning(strMessage);
     LogPrintf("*** %s\n", strMessage);
     uiInterface.ThreadSafeMessageBox(
         userMessage.empty() ? _("Error: A fatal internal error occurred, see "
                                 "debug.log for details")
                             : userMessage,
         "", CClientUIInterface::MSG_ERROR);
     StartShutdown();
     return false;
 }
 
 bool AbortNode(CValidationState &state, const std::string &strMessage,
                const std::string &userMessage = "") {
     AbortNode(strMessage, userMessage);
     return state.Error(strMessage);
 }
 
 } // anon namespace
 
 /**
  * Apply the undo operation of a CTxInUndo to the given chain state.
  * @param undo The undo object.
  * @param view The coins view to which to apply the changes.
  * @param out The out point that corresponds to the tx input.
  * @return True on success.
  */
 bool ApplyTxInUndo(const CTxInUndo &undo, CCoinsViewCache &view,
                    const COutPoint &out) {
     bool fClean = true;
 
     CCoinsModifier coins = view.ModifyCoins(out.hash);
     if (undo.nHeight != 0) {
         // undo data contains height: this is the last output of the prevout tx
         // being spent
         if (!coins->IsPruned())
             fClean = fClean &&
                      error("%s: undo data overwriting existing transaction",
                            __func__);
         coins->Clear();
         coins->fCoinBase = undo.fCoinBase;
         coins->nHeight = undo.nHeight;
         coins->nVersion = undo.nVersion;
     } else {
         if (coins->IsPruned())
             fClean = fClean &&
                      error("%s: undo data adding output to missing transaction",
                            __func__);
     }
     if (coins->IsAvailable(out.n))
         fClean = fClean &&
                  error("%s: undo data overwriting existing output", __func__);
     if (coins->vout.size() < out.n + 1) coins->vout.resize(out.n + 1);
     coins->vout[out.n] = undo.txout;
 
     return fClean;
 }
 
 bool DisconnectBlock(const CBlock &block, CValidationState &state,
                      const CBlockIndex *pindex, CCoinsViewCache &view,
                      bool *pfClean) {
     assert(pindex->GetBlockHash() == view.GetBestBlock());
 
     if (pfClean) *pfClean = false;
 
     CBlockUndo blockUndo;
     CDiskBlockPos pos = pindex->GetUndoPos();
     if (pos.IsNull()) return error("DisconnectBlock(): no undo data available");
     if (!UndoReadFromDisk(blockUndo, pos, pindex->pprev->GetBlockHash()))
         return error("DisconnectBlock(): failure reading undo data");
 
     return ApplyBlockUndo(block, state, pindex, view, blockUndo, pfClean);
 }
 
 bool ApplyBlockUndo(const CBlock &block, CValidationState &state,
                     const CBlockIndex *pindex, CCoinsViewCache &view,
                     const CBlockUndo &blockUndo, bool *pfClean) {
     if (pfClean) *pfClean = false;
     bool fClean = true;
 
     if (blockUndo.vtxundo.size() + 1 != block.vtx.size())
         return error("DisconnectBlock(): block and undo data inconsistent");
 
     // Undo transactions in reverse order.
     size_t i = block.vtx.size();
     while (i-- > 0) {
         const CTransaction &tx = *(block.vtx[i]);
         uint256 txid = tx.GetId();
 
         // Check that all outputs are available and match the outputs in the
         // block itself exactly.
         {
             CCoinsModifier outs = view.ModifyCoins(txid);
             outs->ClearUnspendable();
 
             CCoins outsBlock(tx, pindex->nHeight);
             // The CCoins serialization does not serialize negative numbers. No
             // network rules currently depend on the version here, so an
             // inconsistency is harmless but it must be corrected before txout
             // nversion ever influences a network rule.
             if (outsBlock.nVersion < 0) outs->nVersion = outsBlock.nVersion;
             if (*outs != outsBlock)
                 fClean = fClean && error("DisconnectBlock(): added transaction "
                                          "mismatch? database corrupted");
 
             // Remove outputs.
             outs->Clear();
         }
 
         // Restore inputs.
         if (i < 1) {
             // Skip the coinbase.
             continue;
         }
 
         const CTxUndo &txundo = blockUndo.vtxundo[i - 1];
         if (txundo.vprevout.size() != tx.vin.size())
             return error("DisconnectBlock(): transaction and undo data "
                          "inconsistent");
         for (unsigned int j = tx.vin.size(); j-- > 0;) {
             const COutPoint &out = tx.vin[j].prevout;
             const CTxInUndo &undo = txundo.vprevout[j];
             if (!ApplyTxInUndo(undo, view, out)) fClean = false;
         }
     }
 
     // Move best block pointer to previous block.
     view.SetBestBlock(block.hashPrevBlock);
     if (pfClean) {
         *pfClean = fClean;
         return true;
     }
 
     return fClean;
 }
 
 void static FlushBlockFile(bool fFinalize = false) {
     LOCK(cs_LastBlockFile);
 
     CDiskBlockPos posOld(nLastBlockFile, 0);
 
     FILE *fileOld = OpenBlockFile(posOld);
     if (fileOld) {
         if (fFinalize)
             TruncateFile(fileOld, vinfoBlockFile[nLastBlockFile].nSize);
         FileCommit(fileOld);
         fclose(fileOld);
     }
 
     fileOld = OpenUndoFile(posOld);
     if (fileOld) {
         if (fFinalize)
             TruncateFile(fileOld, vinfoBlockFile[nLastBlockFile].nUndoSize);
         FileCommit(fileOld);
         fclose(fileOld);
     }
 }
 
 bool FindUndoPos(CValidationState &state, int nFile, CDiskBlockPos &pos,
                  unsigned int nAddSize);
 
 static CCheckQueue<CScriptCheck> scriptcheckqueue(128);
 
 void ThreadScriptCheck() {
     RenameThread("bitcoin-scriptch");
     scriptcheckqueue.Thread();
 }
 
 // Protected by cs_main
 VersionBitsCache versionbitscache;
 
 int32_t ComputeBlockVersion(const CBlockIndex *pindexPrev,
                             const Consensus::Params &params) {
     LOCK(cs_main);
     int32_t nVersion = VERSIONBITS_TOP_BITS;
 
     for (int i = 0; i < (int)Consensus::MAX_VERSION_BITS_DEPLOYMENTS; i++) {
         ThresholdState state = VersionBitsState(
             pindexPrev, params, (Consensus::DeploymentPos)i, versionbitscache);
         if (state == THRESHOLD_LOCKED_IN || state == THRESHOLD_STARTED) {
             nVersion |= VersionBitsMask(params, (Consensus::DeploymentPos)i);
         }
     }
 
     return nVersion;
 }
 
 /**
  * Threshold condition checker that triggers when unknown versionbits are seen
  * on the network.
  */
 class WarningBitsConditionChecker : public AbstractThresholdConditionChecker {
 private:
     int bit;
 
 public:
     WarningBitsConditionChecker(int bitIn) : bit(bitIn) {}
 
     int64_t BeginTime(const Consensus::Params &params) const { return 0; }
     int64_t EndTime(const Consensus::Params &params) const {
         return std::numeric_limits<int64_t>::max();
     }
     int Period(const Consensus::Params &params) const {
         return params.nMinerConfirmationWindow;
     }
     int Threshold(const Consensus::Params &params) const {
         return params.nRuleChangeActivationThreshold;
     }
 
     bool Condition(const CBlockIndex *pindex,
                    const Consensus::Params &params) const {
         return ((pindex->nVersion & VERSIONBITS_TOP_MASK) ==
                 VERSIONBITS_TOP_BITS) &&
                ((pindex->nVersion >> bit) & 1) != 0 &&
                ((ComputeBlockVersion(pindex->pprev, params) >> bit) & 1) == 0;
     }
 };
 
 // Protected by cs_main
 static ThresholdConditionCache warningcache[VERSIONBITS_NUM_BITS];
 
 static int64_t nTimeCheck = 0;
 static int64_t nTimeForks = 0;
 static int64_t nTimeVerify = 0;
 static int64_t nTimeConnect = 0;
 static int64_t nTimeIndex = 0;
 static int64_t nTimeCallbacks = 0;
 static int64_t nTimeTotal = 0;
 
 bool ConnectBlock(const Config &config, const CBlock &block,
                   CValidationState &state, CBlockIndex *pindex,
                   CCoinsViewCache &view, const CChainParams &chainparams,
                   bool fJustCheck) {
     AssertLockHeld(cs_main);
 
     int64_t nTimeStart = GetTimeMicros();
 
     // Check it again in case a previous version let a bad block in
     if (!CheckBlock(config, block, state, chainparams.GetConsensus(),
                     !fJustCheck, !fJustCheck))
         return error("%s: Consensus::CheckBlock: %s", __func__,
                      FormatStateMessage(state));
 
     // verify that the view's current state corresponds to the previous block
     uint256 hashPrevBlock =
         pindex->pprev == nullptr ? uint256() : pindex->pprev->GetBlockHash();
     assert(hashPrevBlock == view.GetBestBlock());
 
     // Special case for the genesis block, skipping connection of its
     // transactions (its coinbase is unspendable)
     if (block.GetHash() == chainparams.GetConsensus().hashGenesisBlock) {
         if (!fJustCheck) view.SetBestBlock(pindex->GetBlockHash());
         return true;
     }
 
     bool fScriptChecks = true;
     if (!hashAssumeValid.IsNull()) {
         // We've been configured with the hash of a block which has been
         // externally verified to have a valid history. A suitable default value
         // is included with the software and updated from time to time. Because
         // validity relative to a piece of software is an objective fact these
         // defaults can be easily reviewed. This setting doesn't force the
         // selection of any particular chain but makes validating some faster by
         // effectively caching the result of part of the verification.
         BlockMap::const_iterator it = mapBlockIndex.find(hashAssumeValid);
         if (it != mapBlockIndex.end()) {
             if (it->second->GetAncestor(pindex->nHeight) == pindex &&
                 pindexBestHeader->GetAncestor(pindex->nHeight) == pindex &&
                 pindexBestHeader->nChainWork >=
                     UintToArith256(
                         chainparams.GetConsensus().nMinimumChainWork)) {
                 // This block is a member of the assumed verified chain and an
                 // ancestor of the best header. The equivalent time check
                 // discourages hashpower from extorting the network via DOS
                 // attack into accepting an invalid block through telling users
                 // they must manually set assumevalid. Requiring a software
                 // change or burying the invalid block, regardless of the
                 // setting, makes it hard to hide the implication of the demand.
                 // This also avoids having release candidates that are hardly
                 // doing any signature verification at all in testing without
                 // having to artificially set the default assumed verified block
                 // further back. The test against nMinimumChainWork prevents the
                 // skipping when denied access to any chain at least as good as
                 // the expected chain.
                 fScriptChecks =
                     (GetBlockProofEquivalentTime(
                          *pindexBestHeader, *pindex, *pindexBestHeader,
                          chainparams.GetConsensus()) <= 60 * 60 * 24 * 7 * 2);
             }
         }
     }
 
     int64_t nTime1 = GetTimeMicros();
     nTimeCheck += nTime1 - nTimeStart;
     LogPrint("bench", "    - Sanity checks: %.2fms [%.2fs]\n",
              0.001 * (nTime1 - nTimeStart), nTimeCheck * 0.000001);
 
     // Do not allow blocks that contain transactions which 'overwrite' older
     // transactions, unless those are already completely spent. If such
     // overwrites are allowed, coinbases and transactions depending upon those
     // can be duplicated to remove the ability to spend the first instance --
     // even after being sent to another address. See BIP30 and
     // http://r6.ca/blog/20120206T005236Z.html for more information. This logic
     // is not necessary for memory pool transactions, as AcceptToMemoryPool
     // already refuses previously-known transaction ids entirely. This rule was
     // originally applied to all blocks with a timestamp after March 15, 2012,
     // 0:00 UTC. Now that the whole chain is irreversibly beyond that time it is
     // applied to all blocks except the two in the chain that violate it. This
     // prevents exploiting the issue against nodes during their initial block
     // download.
     bool fEnforceBIP30 = (!pindex->phashBlock) || // Enforce on CreateNewBlock
                                                   // invocations which don't
                                                   // have a hash.
                          !((pindex->nHeight == 91842 &&
                             pindex->GetBlockHash() ==
                                 uint256S("0x00000000000a4d0a398161ffc163c503763"
                                          "b1f4360639393e0e4c8e300e0caec")) ||
                            (pindex->nHeight == 91880 &&
                             pindex->GetBlockHash() ==
                                 uint256S("0x00000000000743f190a18c5577a3c2d2a1f"
                                          "610ae9601ac046a38084ccb7cd721")));
 
     // Once BIP34 activated it was not possible to create new duplicate
     // coinbases and thus other than starting with the 2 existing duplicate
     // coinbase pairs, not possible to create overwriting txs. But by the time
     // BIP34 activated, in each of the existing pairs the duplicate coinbase had
     // overwritten the first before the first had been spent. Since those
     // coinbases are sufficiently buried its no longer possible to create
     // further duplicate transactions descending from the known pairs either. If
     // we're on the known chain at height greater than where BIP34 activated, we
     // can save the db accesses needed for the BIP30 check.
     CBlockIndex *pindexBIP34height =
         pindex->pprev->GetAncestor(chainparams.GetConsensus().BIP34Height);
     // Only continue to enforce if we're below BIP34 activation height or the
     // block hash at that height doesn't correspond.
     fEnforceBIP30 = fEnforceBIP30 && (!pindexBIP34height ||
                                       !(pindexBIP34height->GetBlockHash() ==
                                         chainparams.GetConsensus().BIP34Hash));
 
     if (fEnforceBIP30) {
         for (const auto &tx : block.vtx) {
             const CCoins *coins = view.AccessCoins(tx->GetId());
             if (coins && !coins->IsPruned())
                 return state.DoS(
                     100,
                     error("ConnectBlock(): tried to overwrite transaction"),
                     REJECT_INVALID, "bad-txns-BIP30");
         }
     }
 
     // BIP16 didn't become active until Apr 1 2012
     int64_t nBIP16SwitchTime = 1333238400;
     bool fStrictPayToScriptHash = (pindex->GetBlockTime() >= nBIP16SwitchTime);
 
     unsigned int flags =
         fStrictPayToScriptHash ? SCRIPT_VERIFY_P2SH : SCRIPT_VERIFY_NONE;
 
     // Start enforcing the DERSIG (BIP66) rule
     if (pindex->nHeight >= chainparams.GetConsensus().BIP66Height) {
         flags |= SCRIPT_VERIFY_DERSIG;
     }
 
     // Start enforcing CHECKLOCKTIMEVERIFY (BIP65) rule
     if (pindex->nHeight >= chainparams.GetConsensus().BIP65Height) {
         flags |= SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY;
     }
 
     // Start enforcing BIP68 (sequence locks) and BIP112 (CHECKSEQUENCEVERIFY)
     // using versionbits logic.
     int nLockTimeFlags = 0;
     if (VersionBitsState(pindex->pprev, chainparams.GetConsensus(),
                          Consensus::DEPLOYMENT_CSV,
                          versionbitscache) == THRESHOLD_ACTIVE) {
         flags |= SCRIPT_VERIFY_CHECKSEQUENCEVERIFY;
         nLockTimeFlags |= LOCKTIME_VERIFY_SEQUENCE;
     }
 
     // If the UAHF is enabled, we start accepting replay protected txns
     if (IsUAHFenabled(config, pindex->pprev)) {
         flags |= SCRIPT_ENABLE_SIGHASH_FORKID;
     }
 
     int64_t nTime2 = GetTimeMicros();
     nTimeForks += nTime2 - nTime1;
     LogPrint("bench", "    - Fork checks: %.2fms [%.2fs]\n",
              0.001 * (nTime2 - nTime1), nTimeForks * 0.000001);
 
     CBlockUndo blockundo;
 
     CCheckQueueControl<CScriptCheck> control(
         fScriptChecks && nScriptCheckThreads ? &scriptcheckqueue : nullptr);
 
     std::vector<int> prevheights;
     CAmount nFees = 0;
     int nInputs = 0;
 
     // Sigops counting. We need to do it again because of P2SH.
     uint64_t nSigOpsCount = 0;
     const uint64_t currentBlockSize =
         ::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION);
     const uint64_t nMaxSigOpsCount = GetMaxBlockSigOpsCount(currentBlockSize);
 
     CDiskTxPos pos(pindex->GetBlockPos(),
                    GetSizeOfCompactSize(block.vtx.size()));
     std::vector<std::pair<uint256, CDiskTxPos>> vPos;
     vPos.reserve(block.vtx.size());
     blockundo.vtxundo.reserve(block.vtx.size() - 1);
 
     for (unsigned int i = 0; i < block.vtx.size(); i++) {
         const CTransaction &tx = *(block.vtx[i]);
 
         nInputs += tx.vin.size();
 
         if (!tx.IsCoinBase()) {
             if (!view.HaveInputs(tx))
                 return state.DoS(
                     100, error("ConnectBlock(): inputs missing/spent"),
                     REJECT_INVALID, "bad-txns-inputs-missingorspent");
 
             // Check that transaction is BIP68 final BIP68 lock checks (as
             // opposed to nLockTime checks) must be in ConnectBlock because they
             // require the UTXO set.
             prevheights.resize(tx.vin.size());
             for (size_t j = 0; j < tx.vin.size(); j++) {
                 prevheights[j] =
                     view.AccessCoins(tx.vin[j].prevout.hash)->nHeight;
             }
 
             if (!SequenceLocks(tx, nLockTimeFlags, &prevheights, *pindex)) {
                 return state.DoS(
                     100, error("%s: contains a non-BIP68-final transaction",
                                __func__),
                     REJECT_INVALID, "bad-txns-nonfinal");
             }
         }
 
         // GetTransactionSigOpCount counts 2 types of sigops:
         // * legacy (always)
         // * p2sh (when P2SH enabled in flags and excludes coinbase)
         auto txSigOpsCount = GetTransactionSigOpCount(tx, view, flags);
         if (txSigOpsCount > MAX_TX_SIGOPS_COUNT) {
             return state.DoS(100, false, REJECT_INVALID, "bad-txn-sigops");
         }
 
         nSigOpsCount += txSigOpsCount;
         if (nSigOpsCount > nMaxSigOpsCount) {
             return state.DoS(100, error("ConnectBlock(): too many sigops"),
                              REJECT_INVALID, "bad-blk-sigops");
         }
 
         if (!tx.IsCoinBase()) {
             nFees += view.GetValueIn(tx) - tx.GetValueOut();
 
             // Don't cache results if we're actually connecting blocks (still
             // consult the cache, though).
             bool fCacheResults = fJustCheck;
 
             std::vector<CScriptCheck> vChecks;
             if (!CheckInputs(tx, state, view, fScriptChecks, flags,
                              fCacheResults, PrecomputedTransactionData(tx),
                              nScriptCheckThreads ? &vChecks : nullptr)) {
                 return error("ConnectBlock(): CheckInputs on %s failed with %s",
                              tx.GetId().ToString(), FormatStateMessage(state));
             }
 
             control.Add(vChecks);
         }
 
         CTxUndo undoDummy;
         if (i > 0) {
             blockundo.vtxundo.push_back(CTxUndo());
         }
         UpdateCoins(tx, view, i == 0 ? undoDummy : blockundo.vtxundo.back(),
                     pindex->nHeight);
 
         vPos.push_back(std::make_pair(tx.GetId(), pos));
         pos.nTxOffset += ::GetSerializeSize(tx, SER_DISK, CLIENT_VERSION);
     }
 
     int64_t nTime3 = GetTimeMicros();
     nTimeConnect += nTime3 - nTime2;
     LogPrint("bench", "      - Connect %u transactions: %.2fms (%.3fms/tx, "
                       "%.3fms/txin) [%.2fs]\n",
              (unsigned)block.vtx.size(), 0.001 * (nTime3 - nTime2),
              0.001 * (nTime3 - nTime2) / block.vtx.size(),
              nInputs <= 1 ? 0 : 0.001 * (nTime3 - nTime2) / (nInputs - 1),
              nTimeConnect * 0.000001);
 
     CAmount blockReward =
         nFees + GetBlockSubsidy(pindex->nHeight, chainparams.GetConsensus());
     if (block.vtx[0]->GetValueOut() > blockReward) {
         return state.DoS(100, error("ConnectBlock(): coinbase pays too much "
                                     "(actual=%d vs limit=%d)",
                                     block.vtx[0]->GetValueOut(), blockReward),
                          REJECT_INVALID, "bad-cb-amount");
     }
 
     if (!control.Wait()) {
         return state.DoS(100, false, REJECT_INVALID, "blk-bad-inputs", false,
                          "parallel script check failed");
     }
 
     int64_t nTime4 = GetTimeMicros();
     nTimeVerify += nTime4 - nTime2;
     LogPrint("bench", "    - Verify %u txins: %.2fms (%.3fms/txin) [%.2fs]\n",
              nInputs - 1, 0.001 * (nTime4 - nTime2),
              nInputs <= 1 ? 0 : 0.001 * (nTime4 - nTime2) / (nInputs - 1),
              nTimeVerify * 0.000001);
 
     if (fJustCheck) {
         return true;
     }
 
     // Write undo information to disk
     if (pindex->GetUndoPos().IsNull() ||
         !pindex->IsValid(BLOCK_VALID_SCRIPTS)) {
         if (pindex->GetUndoPos().IsNull()) {
             CDiskBlockPos _pos;
             if (!FindUndoPos(
                     state, pindex->nFile, _pos,
                     ::GetSerializeSize(blockundo, SER_DISK, CLIENT_VERSION) +
                         40)) {
                 return error("ConnectBlock(): FindUndoPos failed");
             }
             if (!UndoWriteToDisk(blockundo, _pos, pindex->pprev->GetBlockHash(),
                                  chainparams.MessageStart())) {
                 return AbortNode(state, "Failed to write undo data");
             }
 
             // update nUndoPos in block index
             pindex->nUndoPos = _pos.nPos;
             pindex->nStatus |= BLOCK_HAVE_UNDO;
         }
 
         pindex->RaiseValidity(BLOCK_VALID_SCRIPTS);
         setDirtyBlockIndex.insert(pindex);
     }
 
     if (fTxIndex && !pblocktree->WriteTxIndex(vPos)) {
         return AbortNode(state, "Failed to write transaction index");
     }
 
     // add this block to the view's block chain
     view.SetBestBlock(pindex->GetBlockHash());
 
     int64_t nTime5 = GetTimeMicros();
     nTimeIndex += nTime5 - nTime4;
     LogPrint("bench", "    - Index writing: %.2fms [%.2fs]\n",
              0.001 * (nTime5 - nTime4), nTimeIndex * 0.000001);
 
     // Watch for changes to the previous coinbase transaction.
     static uint256 hashPrevBestCoinBase;
     GetMainSignals().UpdatedTransaction(hashPrevBestCoinBase);
     hashPrevBestCoinBase = block.vtx[0]->GetId();
 
     int64_t nTime6 = GetTimeMicros();
     nTimeCallbacks += nTime6 - nTime5;
     LogPrint("bench", "    - Callbacks: %.2fms [%.2fs]\n",
              0.001 * (nTime6 - nTime5), nTimeCallbacks * 0.000001);
 
     return true;
 }
 
 /**
  * Update the on-disk chain state.
  * The caches and indexes are flushed depending on the mode we're called with
  * if they're too large, if it's been a while since the last write,
  * or always and in all cases if we're in prune mode and are deleting files.
  */
 bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode,
                              int nManualPruneHeight) {
     int64_t nMempoolUsage = mempool.DynamicMemoryUsage();
     const CChainParams &chainparams = Params();
     LOCK2(cs_main, cs_LastBlockFile);
     static int64_t nLastWrite = 0;
     static int64_t nLastFlush = 0;
     static int64_t nLastSetChain = 0;
     std::set<int> setFilesToPrune;
     bool fFlushForPrune = false;
     try {
         if (fPruneMode && (fCheckForPruning || nManualPruneHeight > 0) &&
             !fReindex) {
             if (nManualPruneHeight > 0) {
                 FindFilesToPruneManual(setFilesToPrune, nManualPruneHeight);
             } else {
                 FindFilesToPrune(setFilesToPrune,
                                  chainparams.PruneAfterHeight());
                 fCheckForPruning = false;
             }
             if (!setFilesToPrune.empty()) {
                 fFlushForPrune = true;
                 if (!fHavePruned) {
                     pblocktree->WriteFlag("prunedblockfiles", true);
                     fHavePruned = true;
                 }
             }
         }
         int64_t nNow = GetTimeMicros();
         // Avoid writing/flushing immediately after startup.
         if (nLastWrite == 0) {
             nLastWrite = nNow;
         }
         if (nLastFlush == 0) {
             nLastFlush = nNow;
         }
         if (nLastSetChain == 0) {
             nLastSetChain = nNow;
         }
         int64_t nMempoolSizeMax =
             GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000;
         int64_t cacheSize =
             pcoinsTip->DynamicMemoryUsage() * DB_PEAK_USAGE_FACTOR;
         int64_t nTotalSpace =
             nCoinCacheUsage +
             std::max<int64_t>(nMempoolSizeMax - nMempoolUsage, 0);
         // The cache is large and we're within 10% and 200 MiB or 50% and 50MiB
         // of the limit, but we have time now (not in the middle of a block
         // processing).
         bool fCacheLarge =
             mode == FLUSH_STATE_PERIODIC &&
             cacheSize >
                 std::min(std::max(nTotalSpace / 2,
                                   nTotalSpace -
                                       MIN_BLOCK_COINSDB_USAGE * 1024 * 1024),
                          std::max((9 * nTotalSpace) / 10,
                                   nTotalSpace -
                                       MAX_BLOCK_COINSDB_USAGE * 1024 * 1024));
         // The cache is over the limit, we have to write now.
         bool fCacheCritical =
             mode == FLUSH_STATE_IF_NEEDED && cacheSize > nTotalSpace;
         // It's been a while since we wrote the block index to disk. Do this
         // frequently, so we don't need to redownload after a crash.
         bool fPeriodicWrite =
             mode == FLUSH_STATE_PERIODIC &&
             nNow > nLastWrite + (int64_t)DATABASE_WRITE_INTERVAL * 1000000;
         // It's been very long since we flushed the cache. Do this infrequently,
         // to optimize cache usage.
         bool fPeriodicFlush =
             mode == FLUSH_STATE_PERIODIC &&
             nNow > nLastFlush + (int64_t)DATABASE_FLUSH_INTERVAL * 1000000;
         // Combine all conditions that result in a full cache flush.
         bool fDoFullFlush = (mode == FLUSH_STATE_ALWAYS) || fCacheLarge ||
                             fCacheCritical || fPeriodicFlush || fFlushForPrune;
         // Write blocks and block index to disk.
         if (fDoFullFlush || fPeriodicWrite) {
             // Depend on nMinDiskSpace to ensure we can write block index
             if (!CheckDiskSpace(0)) return state.Error("out of disk space");
             // First make sure all block and undo data is flushed to disk.
             FlushBlockFile();
             // Then update all block file information (which may refer to block
             // and undo files).
             {
                 std::vector<std::pair<int, const CBlockFileInfo *>> vFiles;
                 vFiles.reserve(setDirtyFileInfo.size());
                 for (std::set<int>::iterator it = setDirtyFileInfo.begin();
                      it != setDirtyFileInfo.end();) {
                     vFiles.push_back(std::make_pair(*it, &vinfoBlockFile[*it]));
                     setDirtyFileInfo.erase(it++);
                 }
                 std::vector<const CBlockIndex *> vBlocks;
                 vBlocks.reserve(setDirtyBlockIndex.size());
                 for (std::set<CBlockIndex *>::iterator it =
                          setDirtyBlockIndex.begin();
                      it != setDirtyBlockIndex.end();) {
                     vBlocks.push_back(*it);
                     setDirtyBlockIndex.erase(it++);
                 }
                 if (!pblocktree->WriteBatchSync(vFiles, nLastBlockFile,
                                                 vBlocks)) {
                     return AbortNode(state,
                                      "Failed to write to block index database");
                 }
             }
             // Finally remove any pruned files
             if (fFlushForPrune) UnlinkPrunedFiles(setFilesToPrune);
             nLastWrite = nNow;
         }
         // Flush best chain related state. This can only be done if the blocks /
         // block index write was also done.
         if (fDoFullFlush) {
             // Typical CCoins structures on disk are around 128 bytes in size.
             // Pushing a new one to the database can cause it to be written
             // twice (once in the log, and once in the tables). This is already
             // an overestimation, as most will delete an existing entry or
             // overwrite one. Still, use a conservative safety factor of 2.
             if (!CheckDiskSpace(128 * 2 * 2 * pcoinsTip->GetCacheSize()))
                 return state.Error("out of disk space");
             // Flush the chainstate (which may refer to block index entries).
             if (!pcoinsTip->Flush())
                 return AbortNode(state, "Failed to write to coin database");
             nLastFlush = nNow;
         }
         if (fDoFullFlush ||
             ((mode == FLUSH_STATE_ALWAYS || mode == FLUSH_STATE_PERIODIC) &&
              nNow >
                  nLastSetChain + (int64_t)DATABASE_WRITE_INTERVAL * 1000000)) {
             // Update best block in wallet (so we can detect restored wallets).
             GetMainSignals().SetBestChain(chainActive.GetLocator());
             nLastSetChain = nNow;
         }
     } catch (const std::runtime_error &e) {
         return AbortNode(state, std::string("System error while flushing: ") +
                                     e.what());
     }
     return true;
 }
 
 void FlushStateToDisk() {
     CValidationState state;
     FlushStateToDisk(state, FLUSH_STATE_ALWAYS);
 }
 
 void PruneAndFlush() {
     CValidationState state;
     fCheckForPruning = true;
     FlushStateToDisk(state, FLUSH_STATE_NONE);
 }
 
 /** Update chainActive and related internal data structures. */
 static void UpdateTip(const Config &config, CBlockIndex *pindexNew) {
     const CChainParams &chainParams = config.GetChainParams();
 
     chainActive.SetTip(pindexNew);
 
     // New best block
     mempool.AddTransactionsUpdated(1);
 
     cvBlockChange.notify_all();
 
     static bool fWarned = false;
     std::vector<std::string> warningMessages;
     if (!IsInitialBlockDownload()) {
         int nUpgraded = 0;
         const CBlockIndex *pindex = chainActive.Tip();
         for (int bit = 0; bit < VERSIONBITS_NUM_BITS; bit++) {
             WarningBitsConditionChecker checker(bit);
             ThresholdState state = checker.GetStateFor(
                 pindex, chainParams.GetConsensus(), warningcache[bit]);
             if (state == THRESHOLD_ACTIVE || state == THRESHOLD_LOCKED_IN) {
                 if (state == THRESHOLD_ACTIVE) {
                     std::string strWarning =
                         strprintf(_("Warning: unknown new rules activated "
                                     "(versionbit %i)"),
                                   bit);
                     SetMiscWarning(strWarning);
                     if (!fWarned) {
                         AlertNotify(strWarning);
                         fWarned = true;
                     }
                 } else {
                     warningMessages.push_back(
                         strprintf("unknown new rules are about to activate "
                                   "(versionbit %i)",
                                   bit));
                 }
             }
         }
         // Check the version of the last 100 blocks to see if we need to
         // upgrade:
         for (int i = 0; i < 100 && pindex != nullptr; i++) {
             int32_t nExpectedVersion =
                 ComputeBlockVersion(pindex->pprev, chainParams.GetConsensus());
             if (pindex->nVersion > VERSIONBITS_LAST_OLD_BLOCK_VERSION &&
                 (pindex->nVersion & ~nExpectedVersion) != 0)
                 ++nUpgraded;
             pindex = pindex->pprev;
         }
         if (nUpgraded > 0)
             warningMessages.push_back(strprintf(
                 "%d of last 100 blocks have unexpected version", nUpgraded));
         if (nUpgraded > 100 / 2) {
             std::string strWarning =
                 _("Warning: Unknown block versions being mined! It's possible "
                   "unknown rules are in effect");
             // notify GetWarnings(), called by Qt and the JSON-RPC code to warn
             // the user:
             SetMiscWarning(strWarning);
             if (!fWarned) {
                 AlertNotify(strWarning);
                 fWarned = true;
             }
         }
     }
     LogPrintf(
         "%s: new best=%s height=%d version=0x%08x log2_work=%.8g tx=%lu "
         "date='%s' progress=%f cache=%.1fMiB(%utx)",
         __func__, chainActive.Tip()->GetBlockHash().ToString(),
         chainActive.Height(), chainActive.Tip()->nVersion,
         log(chainActive.Tip()->nChainWork.getdouble()) / log(2.0),
         (unsigned long)chainActive.Tip()->nChainTx,
         DateTimeStrFormat("%Y-%m-%d %H:%M:%S",
                           chainActive.Tip()->GetBlockTime()),
         GuessVerificationProgress(chainParams.TxData(), chainActive.Tip()),
         pcoinsTip->DynamicMemoryUsage() * (1.0 / (1 << 20)),
         pcoinsTip->GetCacheSize());
     if (!warningMessages.empty())
         LogPrintf(" warning='%s'",
                   boost::algorithm::join(warningMessages, ", "));
     LogPrintf("\n");
 }
 
 /**
  * Disconnect chainActive's tip. You probably want to call
  * mempool.removeForReorg and manually re-limit mempool size after this, with
  * cs_main held.
  */
 static bool DisconnectTip(const Config &config, CValidationState &state,
                           bool fBare = false) {
     const Consensus::Params &consensusParams =
         config.GetChainParams().GetConsensus();
     CBlockIndex *pindexDelete = chainActive.Tip();
     assert(pindexDelete);
     // Read block from disk.
     CBlock block;
     if (!ReadBlockFromDisk(block, pindexDelete, consensusParams)) {
         return AbortNode(state, "Failed to read block");
     }
     // Apply the block atomically to the chain state.
     int64_t nStart = GetTimeMicros();
     {
         CCoinsViewCache view(pcoinsTip);
         if (!DisconnectBlock(block, state, pindexDelete, view)) {
             return error("DisconnectTip(): DisconnectBlock %s failed",
                          pindexDelete->GetBlockHash().ToString());
         }
         bool flushed = view.Flush();
         assert(flushed);
     }
     LogPrint("bench", "- Disconnect block: %.2fms\n",
              (GetTimeMicros() - nStart) * 0.001);
     // Write the chain state to disk, if necessary.
     if (!FlushStateToDisk(state, FLUSH_STATE_IF_NEEDED)) {
         return false;
     }
 
     // If this block was the activation of the UAHF, then we need to remove
     // transactions that are valid only on the HF chain. There is no easy way to
     // do this so we'll just discard the whole mempool and then add the
     // transaction of the block we just disconnected back.
     if (IsUAHFenabled(config, pindexDelete) &&
         !IsUAHFenabled(config, pindexDelete->pprev)) {
         mempool.clear();
     }
 
     if (!fBare) {
         // Resurrect mempool transactions from the disconnected block.
         std::vector<uint256> vHashUpdate;
         for (const auto &it : block.vtx) {
             const CTransaction &tx = *it;
             // ignore validation errors in resurrected transactions
             CValidationState stateDummy;
             if (tx.IsCoinBase() ||
                 !AcceptToMemoryPool(config, mempool, stateDummy, it, false,
                                     nullptr, nullptr, true)) {
                 mempool.removeRecursive(tx, MemPoolRemovalReason::REORG);
             } else if (mempool.exists(tx.GetId())) {
                 vHashUpdate.push_back(tx.GetId());
             }
         }
         // AcceptToMemoryPool/addUnchecked all assume that new mempool entries
         // have no in-mempool children, which is generally not true when adding
         // previously-confirmed transactions back to the mempool.
         // UpdateTransactionsFromBlock finds descendants of any transactions in
         // this block that were added back and cleans up the mempool state.
         mempool.UpdateTransactionsFromBlock(vHashUpdate);
     }
 
     // Update chainActive and related variables.
     UpdateTip(config, pindexDelete->pprev);
     // Let wallets know transactions went from 1-confirmed to
     // 0-confirmed or conflicted:
     for (const auto &tx : block.vtx) {
         GetMainSignals().SyncTransaction(
             *tx, pindexDelete->pprev,
             CMainSignals::SYNC_TRANSACTION_NOT_IN_BLOCK);
     }
     return true;
 }
 
 static int64_t nTimeReadFromDisk = 0;
 static int64_t nTimeConnectTotal = 0;
 static int64_t nTimeFlush = 0;
 static int64_t nTimeChainState = 0;
 static int64_t nTimePostConnect = 0;
 
 /**
  * Used to track blocks whose transactions were applied to the UTXO state as a
  * part of a single ActivateBestChainStep call.
  */
 struct ConnectTrace {
     std::vector<std::pair<CBlockIndex *, std::shared_ptr<const CBlock>>>
         blocksConnected;
 };
 
 /**
  * Connect a new block to chainActive. pblock is either nullptr or a pointer to
  * a CBlock corresponding to pindexNew, to bypass loading it again from disk.
  *
  * The block is always added to connectTrace (either after loading from disk or
  * by copying pblock) - if that is not intended, care must be taken to remove
  * the last entry in blocksConnected in case of failure.
  */
 static bool ConnectTip(const Config &config, CValidationState &state,
                        CBlockIndex *pindexNew,
                        const std::shared_ptr<const CBlock> &pblock,
                        ConnectTrace &connectTrace) {
     const CChainParams &chainparams = config.GetChainParams();
     assert(pindexNew->pprev == chainActive.Tip());
     // Read block from disk.
     int64_t nTime1 = GetTimeMicros();
     if (!pblock) {
         std::shared_ptr<CBlock> pblockNew = std::make_shared<CBlock>();
         connectTrace.blocksConnected.emplace_back(pindexNew, pblockNew);
         if (!ReadBlockFromDisk(*pblockNew, pindexNew,
                                chainparams.GetConsensus()))
             return AbortNode(state, "Failed to read block");
     } else {
         connectTrace.blocksConnected.emplace_back(pindexNew, pblock);
     }
     const CBlock &blockConnecting = *connectTrace.blocksConnected.back().second;
     // Apply the block atomically to the chain state.
     int64_t nTime2 = GetTimeMicros();
     nTimeReadFromDisk += nTime2 - nTime1;
     int64_t nTime3;
     LogPrint("bench", "  - Load block from disk: %.2fms [%.2fs]\n",
              (nTime2 - nTime1) * 0.001, nTimeReadFromDisk * 0.000001);
     {
         CCoinsViewCache view(pcoinsTip);
         bool rv = ConnectBlock(config, blockConnecting, state, pindexNew, view,
                                chainparams);
         GetMainSignals().BlockChecked(blockConnecting, state);
         if (!rv) {
             if (state.IsInvalid()) {
                 InvalidBlockFound(pindexNew, state);
             }
             return error("ConnectTip(): ConnectBlock %s failed",
                          pindexNew->GetBlockHash().ToString());
         }
         nTime3 = GetTimeMicros();
         nTimeConnectTotal += nTime3 - nTime2;
         LogPrint("bench", "  - Connect total: %.2fms [%.2fs]\n",
                  (nTime3 - nTime2) * 0.001, nTimeConnectTotal * 0.000001);
         bool flushed = view.Flush();
         assert(flushed);
     }
     int64_t nTime4 = GetTimeMicros();
     nTimeFlush += nTime4 - nTime3;
     LogPrint("bench", "  - Flush: %.2fms [%.2fs]\n", (nTime4 - nTime3) * 0.001,
              nTimeFlush * 0.000001);
     // Write the chain state to disk, if necessary.
     if (!FlushStateToDisk(state, FLUSH_STATE_IF_NEEDED)) return false;
     int64_t nTime5 = GetTimeMicros();
     nTimeChainState += nTime5 - nTime4;
     LogPrint("bench", "  - Writing chainstate: %.2fms [%.2fs]\n",
              (nTime5 - nTime4) * 0.001, nTimeChainState * 0.000001);
     // Remove conflicting transactions from the mempool.;
     mempool.removeForBlock(blockConnecting.vtx, pindexNew->nHeight);
     // Update chainActive & related variables.
     UpdateTip(config, pindexNew);
 
     int64_t nTime6 = GetTimeMicros();
     nTimePostConnect += nTime6 - nTime5;
     nTimeTotal += nTime6 - nTime1;
     LogPrint("bench", "  - Connect postprocess: %.2fms [%.2fs]\n",
              (nTime6 - nTime5) * 0.001, nTimePostConnect * 0.000001);
     LogPrint("bench", "- Connect block: %.2fms [%.2fs]\n",
              (nTime6 - nTime1) * 0.001, nTimeTotal * 0.000001);
     return true;
 }
 
 /**
  * Return the tip of the chain with the most work in it, that isn't known to be
  * invalid (it's however far from certain to be valid).
  */
 static CBlockIndex *FindMostWorkChain() {
     do {
         CBlockIndex *pindexNew = nullptr;
 
         // Find the best candidate header.
         {
             std::set<CBlockIndex *, CBlockIndexWorkComparator>::reverse_iterator
                 it = setBlockIndexCandidates.rbegin();
             if (it == setBlockIndexCandidates.rend()) return nullptr;
             pindexNew = *it;
         }
 
         // Check whether all blocks on the path between the currently active
         // chain and the candidate are valid. Just going until the active chain
         // is an optimization, as we know all blocks in it are valid already.
         CBlockIndex *pindexTest = pindexNew;
         bool fInvalidAncestor = false;
         while (pindexTest && !chainActive.Contains(pindexTest)) {
             assert(pindexTest->nChainTx || pindexTest->nHeight == 0);
 
             // Pruned nodes may have entries in setBlockIndexCandidates for
             // which block files have been deleted. Remove those as candidates
             // for the most work chain if we come across them; we can't switch
             // to a chain unless we have all the non-active-chain parent blocks.
             bool fFailedChain = pindexTest->nStatus & BLOCK_FAILED_MASK;
             bool fMissingData = !(pindexTest->nStatus & BLOCK_HAVE_DATA);
             if (fFailedChain || fMissingData) {
                 // Candidate chain is not usable (either invalid or missing
                 // data)
                 if (fFailedChain &&
                     (pindexBestInvalid == nullptr ||
                      pindexNew->nChainWork > pindexBestInvalid->nChainWork))
                     pindexBestInvalid = pindexNew;
                 CBlockIndex *pindexFailed = pindexNew;
                 // Remove the entire chain from the set.
                 while (pindexTest != pindexFailed) {
                     if (fFailedChain) {
                         pindexFailed->nStatus |= BLOCK_FAILED_CHILD;
                     } else if (fMissingData) {
                         // If we're missing data, then add back to
                         // mapBlocksUnlinked, so that if the block arrives in
                         // the future we can try adding to
                         // setBlockIndexCandidates again.
                         mapBlocksUnlinked.insert(
                             std::make_pair(pindexFailed->pprev, pindexFailed));
                     }
                     setBlockIndexCandidates.erase(pindexFailed);
                     pindexFailed = pindexFailed->pprev;
                 }
                 setBlockIndexCandidates.erase(pindexTest);
                 fInvalidAncestor = true;
                 break;
             }
             pindexTest = pindexTest->pprev;
         }
         if (!fInvalidAncestor) return pindexNew;
     } while (true);
 }
 
 /** Delete all entries in setBlockIndexCandidates that are worse than the
  * current tip. */
 static void PruneBlockIndexCandidates() {
     // Note that we can't delete the current block itself, as we may need to
     // return to it later in case a reorganization to a better block fails.
     std::set<CBlockIndex *, CBlockIndexWorkComparator>::iterator it =
         setBlockIndexCandidates.begin();
     while (it != setBlockIndexCandidates.end() &&
            setBlockIndexCandidates.value_comp()(*it, chainActive.Tip())) {
         setBlockIndexCandidates.erase(it++);
     }
     // Either the current tip or a successor of it we're working towards is left
     // in setBlockIndexCandidates.
     assert(!setBlockIndexCandidates.empty());
 }
 
 /**
  * Try to make some progress towards making pindexMostWork the active block.
  * pblock is either nullptr or a pointer to a CBlock corresponding to
  * pindexMostWork.
  */
 static bool ActivateBestChainStep(const Config &config, CValidationState &state,
                                   CBlockIndex *pindexMostWork,
                                   const std::shared_ptr<const CBlock> &pblock,
                                   bool &fInvalidFound,
                                   ConnectTrace &connectTrace) {
     AssertLockHeld(cs_main);
     const CBlockIndex *pindexOldTip = chainActive.Tip();
     const CBlockIndex *pindexFork = chainActive.FindFork(pindexMostWork);
 
     // Disconnect active blocks which are no longer in the best chain.
     bool fBlocksDisconnected = false;
     while (chainActive.Tip() && chainActive.Tip() != pindexFork) {
         if (!DisconnectTip(config, state)) return false;
         fBlocksDisconnected = true;
     }
 
     // Build list of new blocks to connect.
     std::vector<CBlockIndex *> vpindexToConnect;
     bool fContinue = true;
     int nHeight = pindexFork ? pindexFork->nHeight : -1;
     while (fContinue && nHeight != pindexMostWork->nHeight) {
         // Don't iterate the entire list of potential improvements toward the
         // best tip, as we likely only need a few blocks along the way.
         int nTargetHeight = std::min(nHeight + 32, pindexMostWork->nHeight);
         vpindexToConnect.clear();
         vpindexToConnect.reserve(nTargetHeight - nHeight);
         CBlockIndex *pindexIter = pindexMostWork->GetAncestor(nTargetHeight);
         while (pindexIter && pindexIter->nHeight != nHeight) {
             vpindexToConnect.push_back(pindexIter);
             pindexIter = pindexIter->pprev;
         }
         nHeight = nTargetHeight;
 
         // Connect new blocks.
         for (CBlockIndex *pindexConnect :
              boost::adaptors::reverse(vpindexToConnect)) {
             if (!ConnectTip(config, state, pindexConnect,
                             pindexConnect == pindexMostWork
                                 ? pblock
                                 : std::shared_ptr<const CBlock>(),
                             connectTrace)) {
                 if (state.IsInvalid()) {
                     // The block violates a consensus rule.
                     if (!state.CorruptionPossible())
                         InvalidChainFound(vpindexToConnect.back());
                     state = CValidationState();
                     fInvalidFound = true;
                     fContinue = false;
                     // If we didn't actually connect the block, don't notify
                     // listeners about it
                     connectTrace.blocksConnected.pop_back();
                     break;
                 } else {
                     // A system error occurred (disk space, database error,
                     // ...).
                     return false;
                 }
             } else {
                 PruneBlockIndexCandidates();
                 if (!pindexOldTip ||
                     chainActive.Tip()->nChainWork > pindexOldTip->nChainWork) {
                     // We're in a better position than we were. Return
                     // temporarily to release the lock.
                     fContinue = false;
                     break;
                 }
             }
         }
     }
 
     if (fBlocksDisconnected) {
         mempool.removeForReorg(pcoinsTip, chainActive.Tip()->nHeight + 1,
                                STANDARD_LOCKTIME_VERIFY_FLAGS);
         LimitMempoolSize(
             mempool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000,
             GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
     }
     mempool.check(pcoinsTip);
 
     // Callbacks/notifications for a new best chain.
     if (fInvalidFound)
         CheckForkWarningConditionsOnNewFork(vpindexToConnect.back());
     else
         CheckForkWarningConditions();
 
     return true;
 }
 
 static void NotifyHeaderTip() {
     bool fNotify = false;
     bool fInitialBlockDownload = false;
     static CBlockIndex *pindexHeaderOld = nullptr;
     CBlockIndex *pindexHeader = nullptr;
     {
         LOCK(cs_main);
         pindexHeader = pindexBestHeader;
 
         if (pindexHeader != pindexHeaderOld) {
             fNotify = true;
             fInitialBlockDownload = IsInitialBlockDownload();
             pindexHeaderOld = pindexHeader;
         }
     }
     // Send block tip changed notifications without cs_main
     if (fNotify) {
         uiInterface.NotifyHeaderTip(fInitialBlockDownload, pindexHeader);
     }
 }
 
 /**
  * Make the best chain active, in multiple steps. The result is either failure
  * or an activated best chain. pblock is either nullptr or a pointer to a block
  * that is already loaded (to avoid loading it again from disk).
  */
 bool ActivateBestChain(const Config &config, CValidationState &state,
                        std::shared_ptr<const CBlock> pblock) {
     // Note that while we're often called here from ProcessNewBlock, this is
     // far from a guarantee. Things in the P2P/RPC will often end up calling
     // us in the middle of ProcessNewBlock - do not assume pblock is set
     // sanely for performance or correctness!
 
     CBlockIndex *pindexMostWork = nullptr;
     CBlockIndex *pindexNewTip = nullptr;
     do {
         boost::this_thread::interruption_point();
         if (ShutdownRequested()) break;
 
         const CBlockIndex *pindexFork;
         ConnectTrace connectTrace;
         bool fInitialDownload;
         {
             LOCK(cs_main);
             {
                 // TODO: Tempoarily ensure that mempool removals are notified
                 // before connected transactions. This shouldn't matter, but the
                 // abandoned state of transactions in our wallet is currently
                 // cleared when we receive another notification and there is a
                 // race condition where notification of a connected conflict
                 // might cause an outside process to abandon a transaction and
                 // then have it inadvertantly cleared by the notification that
                 // the conflicted transaction was evicted.
                 MemPoolConflictRemovalTracker mrt(mempool);
                 CBlockIndex *pindexOldTip = chainActive.Tip();
                 if (pindexMostWork == nullptr) {
                     pindexMostWork = FindMostWorkChain();
                 }
 
                 // Whether we have anything to do at all.
                 if (pindexMostWork == nullptr ||
                     pindexMostWork == chainActive.Tip())
                     return true;
 
                 bool fInvalidFound = false;
                 std::shared_ptr<const CBlock> nullBlockPtr;
                 if (!ActivateBestChainStep(
                         config, state, pindexMostWork,
                         pblock &&
                                 pblock->GetHash() ==
                                     pindexMostWork->GetBlockHash()
                             ? pblock
                             : nullBlockPtr,
                         fInvalidFound, connectTrace))
                     return false;
 
                 if (fInvalidFound) {
                     // Wipe cache, we may need another branch now.
                     pindexMostWork = nullptr;
                 }
                 pindexNewTip = chainActive.Tip();
                 pindexFork = chainActive.FindFork(pindexOldTip);
                 fInitialDownload = IsInitialBlockDownload();
 
                 // throw all transactions though the signal-interface
 
             } // MemPoolConflictRemovalTracker destroyed and conflict evictions
               // are notified
 
             // Transactions in the connnected block are notified
             for (const auto &pair : connectTrace.blocksConnected) {
                 assert(pair.second);
                 const CBlock &block = *(pair.second);
                 for (unsigned int i = 0; i < block.vtx.size(); i++)
                     GetMainSignals().SyncTransaction(*block.vtx[i], pair.first,
                                                      i);
             }
         }
         // When we reach this point, we switched to a new tip (stored in
         // pindexNewTip).
 
         // Notifications/callbacks that can run without cs_main
 
         // Notify external listeners about the new tip.
         GetMainSignals().UpdatedBlockTip(pindexNewTip, pindexFork,
                                          fInitialDownload);
 
         // Always notify the UI if a new block tip was connected
         if (pindexFork != pindexNewTip) {
             uiInterface.NotifyBlockTip(fInitialDownload, pindexNewTip);
         }
     } while (pindexNewTip != pindexMostWork);
     CheckBlockIndex(config.GetChainParams().GetConsensus());
 
     // Write changes periodically to disk, after relay.
     if (!FlushStateToDisk(state, FLUSH_STATE_PERIODIC)) {
         return false;
     }
 
     return true;
 }
 
 bool PreciousBlock(const Config &config, CValidationState &state,
                    CBlockIndex *pindex) {
     {
         LOCK(cs_main);
         if (pindex->nChainWork < chainActive.Tip()->nChainWork) {
             // Nothing to do, this block is not at the tip.
             return true;
         }
         if (chainActive.Tip()->nChainWork > nLastPreciousChainwork) {
             // The chain has been extended since the last call, reset the
             // counter.
             nBlockReverseSequenceId = -1;
         }
         nLastPreciousChainwork = chainActive.Tip()->nChainWork;
         setBlockIndexCandidates.erase(pindex);
         pindex->nSequenceId = nBlockReverseSequenceId;
         if (nBlockReverseSequenceId > std::numeric_limits<int32_t>::min()) {
             // We can't keep reducing the counter if somebody really wants to
             // call preciousblock 2**31-1 times on the same set of tips...
             nBlockReverseSequenceId--;
         }
         if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS) && pindex->nChainTx) {
             setBlockIndexCandidates.insert(pindex);
             PruneBlockIndexCandidates();
         }
     }
 
     return ActivateBestChain(config, state);
 }
 
 bool InvalidateBlock(const Config &config, CValidationState &state,
                      CBlockIndex *pindex) {
     AssertLockHeld(cs_main);
 
     // Mark the block itself as invalid.
     pindex->nStatus |= BLOCK_FAILED_VALID;
     setDirtyBlockIndex.insert(pindex);
     setBlockIndexCandidates.erase(pindex);
 
     while (chainActive.Contains(pindex)) {
         CBlockIndex *pindexWalk = chainActive.Tip();
         pindexWalk->nStatus |= BLOCK_FAILED_CHILD;
         setDirtyBlockIndex.insert(pindexWalk);
         setBlockIndexCandidates.erase(pindexWalk);
         // ActivateBestChain considers blocks already in chainActive
         // unconditionally valid already, so force disconnect away from it.
         if (!DisconnectTip(config, state)) {
             mempool.removeForReorg(pcoinsTip, chainActive.Tip()->nHeight + 1,
                                    STANDARD_LOCKTIME_VERIFY_FLAGS);
             return false;
         }
     }
 
     LimitMempoolSize(
         mempool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000,
         GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
 
     // The resulting new best tip may not be in setBlockIndexCandidates anymore,
     // so add it again.
     BlockMap::iterator it = mapBlockIndex.begin();
     while (it != mapBlockIndex.end()) {
         if (it->second->IsValid(BLOCK_VALID_TRANSACTIONS) &&
             it->second->nChainTx &&
             !setBlockIndexCandidates.value_comp()(it->second,
                                                   chainActive.Tip())) {
             setBlockIndexCandidates.insert(it->second);
         }
         it++;
     }
 
     InvalidChainFound(pindex);
     mempool.removeForReorg(pcoinsTip, chainActive.Tip()->nHeight + 1,
                            STANDARD_LOCKTIME_VERIFY_FLAGS);
     uiInterface.NotifyBlockTip(IsInitialBlockDownload(), pindex->pprev);
     return true;
 }
 
 bool ResetBlockFailureFlags(CBlockIndex *pindex) {
     AssertLockHeld(cs_main);
 
     int nHeight = pindex->nHeight;
 
     // Remove the invalidity flag from this block and all its descendants.
     BlockMap::iterator it = mapBlockIndex.begin();
     while (it != mapBlockIndex.end()) {
         if (!it->second->IsValid() &&
             it->second->GetAncestor(nHeight) == pindex) {
             it->second->nStatus &= ~BLOCK_FAILED_MASK;
             setDirtyBlockIndex.insert(it->second);
             if (it->second->IsValid(BLOCK_VALID_TRANSACTIONS) &&
                 it->second->nChainTx &&
                 setBlockIndexCandidates.value_comp()(chainActive.Tip(),
                                                      it->second)) {
                 setBlockIndexCandidates.insert(it->second);
             }
             if (it->second == pindexBestInvalid) {
                 // Reset invalid block marker if it was pointing to one of
                 // those.
                 pindexBestInvalid = nullptr;
             }
         }
         it++;
     }
 
     // Remove the invalidity flag from all ancestors too.
     while (pindex != nullptr) {
         if (pindex->nStatus & BLOCK_FAILED_MASK) {
             pindex->nStatus &= ~BLOCK_FAILED_MASK;
             setDirtyBlockIndex.insert(pindex);
         }
         pindex = pindex->pprev;
     }
     return true;
 }
 
 CBlockIndex *AddToBlockIndex(const CBlockHeader &block) {
     // Check for duplicate
     uint256 hash = block.GetHash();
     BlockMap::iterator it = mapBlockIndex.find(hash);
     if (it != mapBlockIndex.end()) return it->second;
 
     // Construct new block index object
     CBlockIndex *pindexNew = new CBlockIndex(block);
     assert(pindexNew);
     // We assign the sequence id to blocks only when the full data is available,
     // to avoid miners withholding blocks but broadcasting headers, to get a
     // competitive advantage.
     pindexNew->nSequenceId = 0;
     BlockMap::iterator mi =
         mapBlockIndex.insert(std::make_pair(hash, pindexNew)).first;
     pindexNew->phashBlock = &((*mi).first);
     BlockMap::iterator miPrev = mapBlockIndex.find(block.hashPrevBlock);
     if (miPrev != mapBlockIndex.end()) {
         pindexNew->pprev = (*miPrev).second;
         pindexNew->nHeight = pindexNew->pprev->nHeight + 1;
         pindexNew->BuildSkip();
     }
     pindexNew->nTimeMax =
         (pindexNew->pprev
              ? std::max(pindexNew->pprev->nTimeMax, pindexNew->nTime)
              : pindexNew->nTime);
     pindexNew->nChainWork =
         (pindexNew->pprev ? pindexNew->pprev->nChainWork : 0) +
         GetBlockProof(*pindexNew);
     pindexNew->RaiseValidity(BLOCK_VALID_TREE);
     if (pindexBestHeader == nullptr ||
         pindexBestHeader->nChainWork < pindexNew->nChainWork)
         pindexBestHeader = pindexNew;
 
     setDirtyBlockIndex.insert(pindexNew);
 
     return pindexNew;
 }
 
 /** Mark a block as having its data received and checked (up to
  * BLOCK_VALID_TRANSACTIONS). */
 bool ReceivedBlockTransactions(const CBlock &block, CValidationState &state,
                                CBlockIndex *pindexNew,
                                const CDiskBlockPos &pos) {
     pindexNew->nTx = block.vtx.size();
     pindexNew->nChainTx = 0;
     pindexNew->nFile = pos.nFile;
     pindexNew->nDataPos = pos.nPos;
     pindexNew->nUndoPos = 0;
     pindexNew->nStatus |= BLOCK_HAVE_DATA;
     pindexNew->RaiseValidity(BLOCK_VALID_TRANSACTIONS);
     setDirtyBlockIndex.insert(pindexNew);
 
     if (pindexNew->pprev == nullptr || pindexNew->pprev->nChainTx) {
         // If pindexNew is the genesis block or all parents are
         // BLOCK_VALID_TRANSACTIONS.
         std::deque<CBlockIndex *> queue;
         queue.push_back(pindexNew);
 
         // Recursively process any descendant blocks that now may be eligible to
         // be connected.
         while (!queue.empty()) {
             CBlockIndex *pindex = queue.front();
             queue.pop_front();
             pindex->nChainTx =
                 (pindex->pprev ? pindex->pprev->nChainTx : 0) + pindex->nTx;
             {
                 LOCK(cs_nBlockSequenceId);
                 pindex->nSequenceId = nBlockSequenceId++;
             }
             if (chainActive.Tip() == nullptr ||
                 !setBlockIndexCandidates.value_comp()(pindex,
                                                       chainActive.Tip())) {
                 setBlockIndexCandidates.insert(pindex);
             }
             std::pair<std::multimap<CBlockIndex *, CBlockIndex *>::iterator,
                       std::multimap<CBlockIndex *, CBlockIndex *>::iterator>
                 range = mapBlocksUnlinked.equal_range(pindex);
             while (range.first != range.second) {
                 std::multimap<CBlockIndex *, CBlockIndex *>::iterator it =
                     range.first;
                 queue.push_back(it->second);
                 range.first++;
                 mapBlocksUnlinked.erase(it);
             }
         }
     } else {
         if (pindexNew->pprev && pindexNew->pprev->IsValid(BLOCK_VALID_TREE)) {
             mapBlocksUnlinked.insert(
                 std::make_pair(pindexNew->pprev, pindexNew));
         }
     }
 
     return true;
 }
 
 bool FindBlockPos(CValidationState &state, CDiskBlockPos &pos,
                   unsigned int nAddSize, unsigned int nHeight, uint64_t nTime,
                   bool fKnown = false) {
     LOCK(cs_LastBlockFile);
 
     unsigned int nFile = fKnown ? pos.nFile : nLastBlockFile;
     if (vinfoBlockFile.size() <= nFile) {
         vinfoBlockFile.resize(nFile + 1);
     }
 
     if (!fKnown) {
         while (vinfoBlockFile[nFile].nSize + nAddSize >= MAX_BLOCKFILE_SIZE) {
             nFile++;
             if (vinfoBlockFile.size() <= nFile) {
                 vinfoBlockFile.resize(nFile + 1);
             }
         }
         pos.nFile = nFile;
         pos.nPos = vinfoBlockFile[nFile].nSize;
     }
 
     if ((int)nFile != nLastBlockFile) {
         if (!fKnown) {
             LogPrintf("Leaving block file %i: %s\n", nLastBlockFile,
                       vinfoBlockFile[nLastBlockFile].ToString());
         }
         FlushBlockFile(!fKnown);
         nLastBlockFile = nFile;
     }
 
     vinfoBlockFile[nFile].AddBlock(nHeight, nTime);
     if (fKnown)
         vinfoBlockFile[nFile].nSize =
             std::max(pos.nPos + nAddSize, vinfoBlockFile[nFile].nSize);
     else
         vinfoBlockFile[nFile].nSize += nAddSize;
 
     if (!fKnown) {
         unsigned int nOldChunks =
             (pos.nPos + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
         unsigned int nNewChunks =
             (vinfoBlockFile[nFile].nSize + BLOCKFILE_CHUNK_SIZE - 1) /
             BLOCKFILE_CHUNK_SIZE;
         if (nNewChunks > nOldChunks) {
             if (fPruneMode) fCheckForPruning = true;
             if (CheckDiskSpace(nNewChunks * BLOCKFILE_CHUNK_SIZE - pos.nPos)) {
                 FILE *file = OpenBlockFile(pos);
                 if (file) {
                     LogPrintf(
                         "Pre-allocating up to position 0x%x in blk%05u.dat\n",
                         nNewChunks * BLOCKFILE_CHUNK_SIZE, pos.nFile);
                     AllocateFileRange(file, pos.nPos,
                                       nNewChunks * BLOCKFILE_CHUNK_SIZE -
                                           pos.nPos);
                     fclose(file);
                 }
             } else
                 return state.Error("out of disk space");
         }
     }
 
     setDirtyFileInfo.insert(nFile);
     return true;
 }
 
 bool FindUndoPos(CValidationState &state, int nFile, CDiskBlockPos &pos,
                  unsigned int nAddSize) {
     pos.nFile = nFile;
 
     LOCK(cs_LastBlockFile);
 
     unsigned int nNewSize;
     pos.nPos = vinfoBlockFile[nFile].nUndoSize;
     nNewSize = vinfoBlockFile[nFile].nUndoSize += nAddSize;
     setDirtyFileInfo.insert(nFile);
 
     unsigned int nOldChunks =
         (pos.nPos + UNDOFILE_CHUNK_SIZE - 1) / UNDOFILE_CHUNK_SIZE;
     unsigned int nNewChunks =
         (nNewSize + UNDOFILE_CHUNK_SIZE - 1) / UNDOFILE_CHUNK_SIZE;
     if (nNewChunks > nOldChunks) {
         if (fPruneMode) fCheckForPruning = true;
         if (CheckDiskSpace(nNewChunks * UNDOFILE_CHUNK_SIZE - pos.nPos)) {
             FILE *file = OpenUndoFile(pos);
             if (file) {
                 LogPrintf("Pre-allocating up to position 0x%x in rev%05u.dat\n",
                           nNewChunks * UNDOFILE_CHUNK_SIZE, pos.nFile);
                 AllocateFileRange(file, pos.nPos,
                                   nNewChunks * UNDOFILE_CHUNK_SIZE - pos.nPos);
                 fclose(file);
             }
         } else
             return state.Error("out of disk space");
     }
 
     return true;
 }
 
 bool CheckBlockHeader(const CBlockHeader &block, CValidationState &state,
                       const Consensus::Params &consensusParams,
                       bool fCheckPOW) {
     // Check proof of work matches claimed amount
     if (fCheckPOW &&
         !CheckProofOfWork(block.GetHash(), block.nBits, consensusParams))
         return state.DoS(50, false, REJECT_INVALID, "high-hash", false,
                          "proof of work failed");
 
     return true;
 }
 
 bool CheckBlock(const Config &config, const CBlock &block,
                 CValidationState &state,
                 const Consensus::Params &consensusParams, bool fCheckPOW,
                 bool fCheckMerkleRoot) {
     // These are checks that are independent of context.
     if (block.fChecked) return true;
 
     // Check that the header is valid (particularly PoW).  This is mostly
     // redundant with the call in AcceptBlockHeader.
     if (!CheckBlockHeader(block, state, consensusParams, fCheckPOW))
         return false;
 
     // Check the merkle root.
     if (fCheckMerkleRoot) {
         bool mutated;
         uint256 hashMerkleRoot2 = BlockMerkleRoot(block, &mutated);
         if (block.hashMerkleRoot != hashMerkleRoot2)
             return state.DoS(100, false, REJECT_INVALID, "bad-txnmrklroot",
                              true, "hashMerkleRoot mismatch");
 
         // Check for merkle tree malleability (CVE-2012-2459): repeating
         // sequences of transactions in a block without affecting the merkle
         // root of a block, while still invalidating it.
         if (mutated)
             return state.DoS(100, false, REJECT_INVALID, "bad-txns-duplicate",
                              true, "duplicate transaction");
     }
 
     // All potential-corruption validation must be done before we do any
     // transaction validation, as otherwise we may mark the header as invalid
     // because we receive the wrong transactions for it.
 
     // First transaction must be coinbase.
     if (block.vtx.empty()) {
         return state.DoS(100, false, REJECT_INVALID, "bad-cb-missing", false,
                          "first tx is not coinbase");
     }
 
     // Size limits.
     auto nMaxBlockSize = config.GetMaxBlockSize();
 
     // Bail early if there is no way this block is of reasonable size.
     if ((block.vtx.size() * MIN_TRANSACTION_SIZE) > nMaxBlockSize) {
         return state.DoS(100, false, REJECT_INVALID, "bad-blk-length", false,
                          "size limits failed");
     }
 
     auto currentBlockSize =
         ::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION);
     if (currentBlockSize > nMaxBlockSize) {
         return state.DoS(100, false, REJECT_INVALID, "bad-blk-length", false,
                          "size limits failed");
     }
 
     // And a valid coinbase.
     if (!CheckCoinbase(*block.vtx[0], state, false)) {
         return state.Invalid(false, state.GetRejectCode(),
                              state.GetRejectReason(),
                              strprintf("Coinbase check failed (txid %s) %s",
                                        block.vtx[0]->GetId().ToString(),
                                        state.GetDebugMessage()));
     }
 
     // Keep track of the sigops count.
     uint64_t nSigOps = 0;
     auto nMaxSigOpsCount = GetMaxBlockSigOpsCount(currentBlockSize);
 
     // Check transactions
     auto txCount = block.vtx.size();
     auto *tx = block.vtx[0].get();
 
     size_t i = 0;
     while (true) {
         // Count the sigops for the current transaction. If the total sigops
         // count is too high, the the block is invalid.
         nSigOps += GetSigOpCountWithoutP2SH(*tx);
         if (nSigOps > nMaxSigOpsCount) {
             return state.DoS(100, false, REJECT_INVALID, "bad-blk-sigops",
                              false, "out-of-bounds SigOpCount");
         }
 
         // Go to the next transaction.
         i++;
 
         // We reached the end of the block, success.
         if (i >= txCount) break;
 
         // Check that the transaction is valid. because this check differs for
         // the coinbase, the loos is arranged such as this only runs after at
         // least one increment.
         tx = block.vtx[i].get();
         if (!CheckRegularTransaction(*tx, state, false)) {
             return state.Invalid(
                 false, state.GetRejectCode(), state.GetRejectReason(),
                 strprintf("Transaction check failed (txid %s) %s",
                           tx->GetId().ToString(), state.GetDebugMessage()));
         }
     }
 
     if (fCheckPOW && fCheckMerkleRoot) {
         block.fChecked = true;
     }
 
     return true;
 }
 
 static bool CheckIndexAgainstCheckpoint(const CBlockIndex *pindexPrev,
                                         CValidationState &state,
                                         const CChainParams &chainparams,
                                         const uint256 &hash) {
     if (*pindexPrev->phashBlock == chainparams.GetConsensus().hashGenesisBlock)
         return true;
 
     int nHeight = pindexPrev->nHeight + 1;
     // Don't accept any forks from the main chain prior to last checkpoint
     CBlockIndex *pcheckpoint =
         Checkpoints::GetLastCheckpoint(chainparams.Checkpoints());
     if (pcheckpoint && nHeight < pcheckpoint->nHeight)
         return state.DoS(
             100,
             error("%s: forked chain older than last checkpoint (height %d)",
                   __func__, nHeight));
 
     return true;
 }
 
 bool ContextualCheckBlockHeader(const CBlockHeader &block,
                                 CValidationState &state,
                                 const Consensus::Params &consensusParams,
                                 const CBlockIndex *pindexPrev,
                                 int64_t nAdjustedTime) {
     const int nHeight = pindexPrev == nullptr ? 0 : pindexPrev->nHeight + 1;
 
     // Check proof of work
     if (block.nBits !=
         GetNextWorkRequired(pindexPrev, &block, consensusParams)) {
         return state.DoS(100, false, REJECT_INVALID, "bad-diffbits", false,
                          "incorrect proof of work");
     }
 
     // Check timestamp against prev
     if (block.GetBlockTime() <= pindexPrev->GetMedianTimePast()) {
         return state.Invalid(false, REJECT_INVALID, "time-too-old",
                              "block's timestamp is too early");
     }
 
     // Check timestamp
     if (block.GetBlockTime() > nAdjustedTime + 2 * 60 * 60) {
         return state.Invalid(false, REJECT_INVALID, "time-too-new",
                              "block timestamp too far in the future");
     }
 
     // Reject outdated version blocks when 95% (75% on testnet) of the network
     // has upgraded:
     // check for version 2, 3 and 4 upgrades
     if ((block.nVersion < 2 && nHeight >= consensusParams.BIP34Height) ||
         (block.nVersion < 3 && nHeight >= consensusParams.BIP66Height) ||
         (block.nVersion < 4 && nHeight >= consensusParams.BIP65Height)) {
         return state.Invalid(
             false, REJECT_OBSOLETE,
             strprintf("bad-version(0x%08x)", block.nVersion),
             strprintf("rejected nVersion=0x%08x block", block.nVersion));
     }
 
     return true;
 }
 
 bool ContextualCheckTransaction(const Config &config, const CTransaction &tx,
                                 CValidationState &state,
                                 const Consensus::Params &consensusParams,
                                 int nHeight, int64_t nLockTimeCutoff,
                                 int64_t nMedianTimePast) {
     if (!IsFinalTx(tx, nHeight, nLockTimeCutoff)) {
         // While this is only one transaction, we use txns in the error to
         // ensure continuity with other clients.
         return state.DoS(10, false, REJECT_INVALID, "bad-txns-nonfinal", false,
                          "non-final transaction");
     }
 
     if (IsUAHFenabled(config, nMedianTimePast) &&
         nHeight <= consensusParams.antiReplayOpReturnSunsetHeight) {
         for (const CTxOut &o : tx.vout) {
             if (o.scriptPubKey.IsCommitment(
                     consensusParams.antiReplayOpReturnCommitment)) {
                 return state.DoS(10, false, REJECT_INVALID, "bad-txn-replay",
                                  false, "non playable transaction");
             }
         }
     }
 
     return true;
 }
 
 bool ContextualCheckTransactionForCurrentBlock(
     const Config &config, const CTransaction &tx, CValidationState &state,
     const Consensus::Params &consensusParams, int flags) {
     AssertLockHeld(cs_main);
 
     // By convention a negative value for flags indicates that the current
     // network-enforced consensus rules should be used. In a future soft-fork
     // scenario that would mean checking which rules would be enforced for the
     // next block and setting the appropriate flags. At the present time no
     // soft-forks are scheduled, so no flags are set.
     flags = std::max(flags, 0);
 
     // ContextualCheckTransactionForCurrentBlock() uses chainActive.Height()+1
     // to evaluate nLockTime because when IsFinalTx() is called within
     // CBlock::AcceptBlock(), the height of the block *being* evaluated is what
     // is used. Thus if we want to know if a transaction can be part of the
     // *next* block, we need to call ContextualCheckTransaction() with one more
     // than chainActive.Height().
     const int nBlockHeight = chainActive.Height() + 1;
 
     // BIP113 will require that time-locked transactions have nLockTime set to
     // less than the median time of the previous block they're contained in.
     // When the next block is created its previous block will be the current
     // chain tip, so we use that to calculate the median time passed to
     // ContextualCheckTransaction() if LOCKTIME_MEDIAN_TIME_PAST is set.
     const int64_t nMedianTimePast = chainActive.Tip()->GetMedianTimePast();
     const int64_t nLockTimeCutoff = (flags & LOCKTIME_MEDIAN_TIME_PAST)
                                         ? nMedianTimePast
                                         : GetAdjustedTime();
 
     return ContextualCheckTransaction(config, tx, state, consensusParams,
                                       nBlockHeight, nLockTimeCutoff,
                                       nMedianTimePast);
 }
 
 bool ContextualCheckBlock(const Config &config, const CBlock &block,
                           CValidationState &state,
                           const Consensus::Params &consensusParams,
                           const CBlockIndex *pindexPrev) {
     const int nHeight = pindexPrev == nullptr ? 0 : pindexPrev->nHeight + 1;
 
     // Start enforcing BIP113 (Median Time Past) using versionbits logic.
     int nLockTimeFlags = 0;
     if (VersionBitsState(pindexPrev, consensusParams, Consensus::DEPLOYMENT_CSV,
                          versionbitscache) == THRESHOLD_ACTIVE) {
         nLockTimeFlags |= LOCKTIME_MEDIAN_TIME_PAST;
     }
 
     if (IsUAHFenabled(config, pindexPrev)) {
         // If UAHF is enabled for the curent block, but not for the previous
         // block, we must check that the block is larger than 1MB.
         if (!IsUAHFenabled(config, pindexPrev->pprev)) {
             const uint64_t currentBlockSize =
                 ::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION);
             if (currentBlockSize <= LEGACY_MAX_BLOCK_SIZE) {
                 return state.DoS(100, false, REJECT_INVALID,
                                  "bad-blk-too-small", false,
                                  "size limits failed");
             }
         }
     } else {
         // When UAHF is not enabled, block cannot be bigger than
         // LEGACY_MAX_BLOCK_SIZE .
         const uint64_t currentBlockSize =
             ::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION);
         if (currentBlockSize > LEGACY_MAX_BLOCK_SIZE) {
             return state.DoS(100, false, REJECT_INVALID, "bad-blk-length",
                              false, "size limits failed");
         }
     }
 
     const int64_t nMedianTimePast =
         pindexPrev == nullptr ? 0 : pindexPrev->GetMedianTimePast();
 
     const int64_t nLockTimeCutoff = (nLockTimeFlags & LOCKTIME_MEDIAN_TIME_PAST)
                                         ? nMedianTimePast
                                         : block.GetBlockTime();
 
     // Check that all transactions are finalized
     for (const auto &tx : block.vtx) {
         if (!ContextualCheckTransaction(config, *tx, state, consensusParams,
                                         nHeight, nLockTimeCutoff,
                                         nMedianTimePast)) {
             // state set by ContextualCheckTransaction.
             return false;
         }
     }
 
     // Enforce rule that the coinbase starts with serialized block height
     if (nHeight >= consensusParams.BIP34Height) {
         CScript expect = CScript() << nHeight;
         if (block.vtx[0]->vin[0].scriptSig.size() < expect.size() ||
             !std::equal(expect.begin(), expect.end(),
                         block.vtx[0]->vin[0].scriptSig.begin())) {
             return state.DoS(100, false, REJECT_INVALID, "bad-cb-height", false,
                              "block height mismatch in coinbase");
         }
     }
 
     return true;
 }
 
 static bool AcceptBlockHeader(const Config &config, const CBlockHeader &block,
                               CValidationState &state, CBlockIndex **ppindex) {
     AssertLockHeld(cs_main);
     const CChainParams &chainparams = config.GetChainParams();
 
     // Check for duplicate
     uint256 hash = block.GetHash();
     BlockMap::iterator miSelf = mapBlockIndex.find(hash);
     CBlockIndex *pindex = nullptr;
     if (hash != chainparams.GetConsensus().hashGenesisBlock) {
 
         if (miSelf != mapBlockIndex.end()) {
             // Block header is already known.
             pindex = miSelf->second;
             if (ppindex) *ppindex = pindex;
             if (pindex->nStatus & BLOCK_FAILED_MASK)
                 return state.Invalid(error("%s: block %s is marked invalid",
                                            __func__, hash.ToString()),
                                      0, "duplicate");
             return true;
         }
 
         if (!CheckBlockHeader(block, state, chainparams.GetConsensus()))
             return error("%s: Consensus::CheckBlockHeader: %s, %s", __func__,
                          hash.ToString(), FormatStateMessage(state));
 
         // Get prev block index
         CBlockIndex *pindexPrev = nullptr;
         BlockMap::iterator mi = mapBlockIndex.find(block.hashPrevBlock);
         if (mi == mapBlockIndex.end())
             return state.DoS(10, error("%s: prev block not found", __func__), 0,
                              "bad-prevblk");
         pindexPrev = (*mi).second;
         if (pindexPrev->nStatus & BLOCK_FAILED_MASK)
             return state.DoS(100, error("%s: prev block invalid", __func__),
                              REJECT_INVALID, "bad-prevblk");
 
         assert(pindexPrev);
         if (fCheckpointsEnabled &&
             !CheckIndexAgainstCheckpoint(pindexPrev, state, chainparams, hash))
             return error("%s: CheckIndexAgainstCheckpoint(): %s", __func__,
                          state.GetRejectReason().c_str());
 
         if (!ContextualCheckBlockHeader(block, state,
                                         chainparams.GetConsensus(), pindexPrev,
                                         GetAdjustedTime()))
             return error("%s: Consensus::ContextualCheckBlockHeader: %s, %s",
                          __func__, hash.ToString(), FormatStateMessage(state));
     }
     if (pindex == nullptr) pindex = AddToBlockIndex(block);
 
     if (ppindex) *ppindex = pindex;
 
     CheckBlockIndex(chainparams.GetConsensus());
 
     return true;
 }
 
 // Exposed wrapper for AcceptBlockHeader
 bool ProcessNewBlockHeaders(const Config &config,
                             const std::vector<CBlockHeader> &headers,
                             CValidationState &state,
                             const CBlockIndex **ppindex) {
     {
         LOCK(cs_main);
         for (const CBlockHeader &header : headers) {
             // Use a temp pindex instead of ppindex to avoid a const_cast
             CBlockIndex *pindex = nullptr;
             if (!AcceptBlockHeader(config, header, state, &pindex)) {
                 return false;
             }
             if (ppindex) {
                 *ppindex = pindex;
             }
         }
     }
     NotifyHeaderTip();
     return true;
 }
 
 /**
  * Store block on disk. If dbp is non-null, the file is known to already reside
  * on disk.
  */
 static bool AcceptBlock(const Config &config,
                         const std::shared_ptr<const CBlock> &pblock,
                         CValidationState &state, CBlockIndex **ppindex,
                         bool fRequested, const CDiskBlockPos *dbp,
                         bool *fNewBlock) {
     const CBlock &block = *pblock;
 
     if (fNewBlock) *fNewBlock = false;
     AssertLockHeld(cs_main);
 
     CBlockIndex *pindexDummy = nullptr;
     CBlockIndex *&pindex = ppindex ? *ppindex : pindexDummy;
 
     if (!AcceptBlockHeader(config, block, state, &pindex)) return false;
 
     // Try to process all requested blocks that we don't have, but only
     // process an unrequested block if it's new and has enough work to
     // advance our tip, and isn't too many blocks ahead.
     bool fAlreadyHave = pindex->nStatus & BLOCK_HAVE_DATA;
     bool fHasMoreWork =
         (chainActive.Tip() ? pindex->nChainWork > chainActive.Tip()->nChainWork
                            : true);
     // Blocks that are too out-of-order needlessly limit the effectiveness of
     // pruning, because pruning will not delete block files that contain any
     // blocks which are too close in height to the tip.  Apply this test
     // regardless of whether pruning is enabled; it should generally be safe to
     // not process unrequested blocks.
     bool fTooFarAhead =
         (pindex->nHeight > int(chainActive.Height() + MIN_BLOCKS_TO_KEEP));
 
     // TODO: Decouple this function from the block download logic by removing
     // fRequested
     // This requires some new chain datastructure to efficiently look up if a
     // block is in a chain leading to a candidate for best tip, despite not
     // being such a candidate itself.
 
     // TODO: deal better with return value and error conditions for duplicate
     // and unrequested blocks.
     if (fAlreadyHave) {
         return true;
     }
 
     // If we didn't ask for it:
     if (!fRequested) {
         // This is a previously-processed block that was pruned.
         if (pindex->nTx != 0) return true;
         // Don't process less-work chains.
         if (!fHasMoreWork) return true;
         // Block height is too high.
         if (fTooFarAhead) return true;
     }
 
     if (fNewBlock) {
         *fNewBlock = true;
     }
 
     const CChainParams &chainparams = config.GetChainParams();
     if (!CheckBlock(config, block, state, chainparams.GetConsensus()) ||
         !ContextualCheckBlock(config, block, state, chainparams.GetConsensus(),
                               pindex->pprev)) {
         if (state.IsInvalid() && !state.CorruptionPossible()) {
             pindex->nStatus |= BLOCK_FAILED_VALID;
             setDirtyBlockIndex.insert(pindex);
         }
         return error("%s: %s", __func__, FormatStateMessage(state));
     }
 
     // Header is valid/has work, merkle tree and segwit merkle tree are
     // good...RELAY NOW (but if it does not build on our best tip, let the
     // SendMessages loop relay it)
     if (!IsInitialBlockDownload() && chainActive.Tip() == pindex->pprev)
         GetMainSignals().NewPoWValidBlock(pindex, pblock);
 
     int nHeight = pindex->nHeight;
 
     // Write block to history file
     try {
         unsigned int nBlockSize =
             ::GetSerializeSize(block, SER_DISK, CLIENT_VERSION);
         CDiskBlockPos blockPos;
         if (dbp != nullptr) blockPos = *dbp;
         if (!FindBlockPos(state, blockPos, nBlockSize + 8, nHeight,
                           block.GetBlockTime(), dbp != nullptr))
             return error("AcceptBlock(): FindBlockPos failed");
         if (dbp == nullptr)
             if (!WriteBlockToDisk(block, blockPos, chainparams.MessageStart()))
                 AbortNode(state, "Failed to write block");
         if (!ReceivedBlockTransactions(block, state, pindex, blockPos))
             return error("AcceptBlock(): ReceivedBlockTransactions failed");
     } catch (const std::runtime_error &e) {
         return AbortNode(state, std::string("System error: ") + e.what());
     }
 
     if (fCheckForPruning) {
         // we just allocated more disk space for block files.
         FlushStateToDisk(state, FLUSH_STATE_NONE);
     }
 
     return true;
 }
 
 bool ProcessNewBlock(const Config &config,
                      const std::shared_ptr<const CBlock> pblock,
                      bool fForceProcessing, bool *fNewBlock) {
     {
         CBlockIndex *pindex = nullptr;
         if (fNewBlock) *fNewBlock = false;
 
         const CChainParams &chainparams = config.GetChainParams();
 
         CValidationState state;
         // Ensure that CheckBlock() passes before calling AcceptBlock, as
         // belt-and-suspenders.
         bool ret =
             CheckBlock(config, *pblock, state, chainparams.GetConsensus());
 
         LOCK(cs_main);
 
         if (ret) {
             // Store to disk
             ret = AcceptBlock(config, pblock, state, &pindex, fForceProcessing,
                               nullptr, fNewBlock);
         }
         CheckBlockIndex(chainparams.GetConsensus());
         if (!ret) {
             GetMainSignals().BlockChecked(*pblock, state);
             return error("%s: AcceptBlock FAILED", __func__);
         }
     }
 
     NotifyHeaderTip();
 
     // Only used to report errors, not invalidity - ignore it
     CValidationState state;
     if (!ActivateBestChain(config, state, pblock))
         return error("%s: ActivateBestChain failed", __func__);
 
     return true;
 }
 
 bool TestBlockValidity(const Config &config, CValidationState &state,
                        const CChainParams &chainparams, const CBlock &block,
                        CBlockIndex *pindexPrev, bool fCheckPOW,
                        bool fCheckMerkleRoot) {
     AssertLockHeld(cs_main);
     assert(pindexPrev && pindexPrev == chainActive.Tip());
     if (fCheckpointsEnabled &&
         !CheckIndexAgainstCheckpoint(pindexPrev, state, chainparams,
                                      block.GetHash()))
         return error("%s: CheckIndexAgainstCheckpoint(): %s", __func__,
                      state.GetRejectReason().c_str());
 
     CCoinsViewCache viewNew(pcoinsTip);
     CBlockIndex indexDummy(block);
     indexDummy.pprev = pindexPrev;
     indexDummy.nHeight = pindexPrev->nHeight + 1;
 
     // NOTE: CheckBlockHeader is called by CheckBlock
     if (!ContextualCheckBlockHeader(block, state, chainparams.GetConsensus(),
                                     pindexPrev, GetAdjustedTime()))
         return error("%s: Consensus::ContextualCheckBlockHeader: %s", __func__,
                      FormatStateMessage(state));
     if (!CheckBlock(config, block, state, chainparams.GetConsensus(), fCheckPOW,
                     fCheckMerkleRoot))
         return error("%s: Consensus::CheckBlock: %s", __func__,
                      FormatStateMessage(state));
     if (!ContextualCheckBlock(config, block, state, chainparams.GetConsensus(),
                               pindexPrev))
         return error("%s: Consensus::ContextualCheckBlock: %s", __func__,
                      FormatStateMessage(state));
     if (!ConnectBlock(config, block, state, &indexDummy, viewNew, chainparams,
                       true))
         return false;
     assert(state.IsValid());
 
     return true;
 }
 
 /**
  * BLOCK PRUNING CODE
  */
 
 /* Calculate the amount of disk space the block & undo files currently use */
 uint64_t CalculateCurrentUsage() {
     uint64_t retval = 0;
     for (const CBlockFileInfo &file : vinfoBlockFile) {
         retval += file.nSize + file.nUndoSize;
     }
     return retval;
 }
 
 /* Prune a block file (modify associated database entries)*/
 void PruneOneBlockFile(const int fileNumber) {
     for (BlockMap::iterator it = mapBlockIndex.begin();
          it != mapBlockIndex.end(); ++it) {
         CBlockIndex *pindex = it->second;
         if (pindex->nFile == fileNumber) {
             pindex->nStatus &= ~BLOCK_HAVE_DATA;
             pindex->nStatus &= ~BLOCK_HAVE_UNDO;
             pindex->nFile = 0;
             pindex->nDataPos = 0;
             pindex->nUndoPos = 0;
             setDirtyBlockIndex.insert(pindex);
 
             // Prune from mapBlocksUnlinked -- any block we prune would have
             // to be downloaded again in order to consider its chain, at which
             // point it would be considered as a candidate for
             // mapBlocksUnlinked or setBlockIndexCandidates.
             std::pair<std::multimap<CBlockIndex *, CBlockIndex *>::iterator,
                       std::multimap<CBlockIndex *, CBlockIndex *>::iterator>
                 range = mapBlocksUnlinked.equal_range(pindex->pprev);
             while (range.first != range.second) {
                 std::multimap<CBlockIndex *, CBlockIndex *>::iterator _it =
                     range.first;
                 range.first++;
                 if (_it->second == pindex) {
                     mapBlocksUnlinked.erase(_it);
                 }
             }
         }
     }
 
     vinfoBlockFile[fileNumber].SetNull();
     setDirtyFileInfo.insert(fileNumber);
 }
 
 void UnlinkPrunedFiles(const std::set<int> &setFilesToPrune) {
     for (std::set<int>::iterator it = setFilesToPrune.begin();
          it != setFilesToPrune.end(); ++it) {
         CDiskBlockPos pos(*it, 0);
         boost::filesystem::remove(GetBlockPosFilename(pos, "blk"));
         boost::filesystem::remove(GetBlockPosFilename(pos, "rev"));
         LogPrintf("Prune: %s deleted blk/rev (%05u)\n", __func__, *it);
     }
 }
 
 /* Calculate the block/rev files to delete based on height specified by user
  * with RPC command pruneblockchain */
 void FindFilesToPruneManual(std::set<int> &setFilesToPrune,
                             int nManualPruneHeight) {
     assert(fPruneMode && nManualPruneHeight > 0);
 
     LOCK2(cs_main, cs_LastBlockFile);
     if (chainActive.Tip() == nullptr) return;
 
     // last block to prune is the lesser of (user-specified height,
     // MIN_BLOCKS_TO_KEEP from the tip)
     unsigned int nLastBlockWeCanPrune =
         std::min((unsigned)nManualPruneHeight,
                  chainActive.Tip()->nHeight - MIN_BLOCKS_TO_KEEP);
     int count = 0;
     for (int fileNumber = 0; fileNumber < nLastBlockFile; fileNumber++) {
         if (vinfoBlockFile[fileNumber].nSize == 0 ||
             vinfoBlockFile[fileNumber].nHeightLast > nLastBlockWeCanPrune)
             continue;
         PruneOneBlockFile(fileNumber);
         setFilesToPrune.insert(fileNumber);
         count++;
     }
     LogPrintf("Prune (Manual): prune_height=%d removed %d blk/rev pairs\n",
               nLastBlockWeCanPrune, count);
 }
 
 /* This function is called from the RPC code for pruneblockchain */
 void PruneBlockFilesManual(int nManualPruneHeight) {
     CValidationState state;
     FlushStateToDisk(state, FLUSH_STATE_NONE, nManualPruneHeight);
 }
 
 /* Calculate the block/rev files that should be deleted to remain under target*/
 void FindFilesToPrune(std::set<int> &setFilesToPrune,
                       uint64_t nPruneAfterHeight) {
     LOCK2(cs_main, cs_LastBlockFile);
     if (chainActive.Tip() == nullptr || nPruneTarget == 0) {
         return;
     }
     if ((uint64_t)chainActive.Tip()->nHeight <= nPruneAfterHeight) {
         return;
     }
 
     unsigned int nLastBlockWeCanPrune =
         chainActive.Tip()->nHeight - MIN_BLOCKS_TO_KEEP;
     uint64_t nCurrentUsage = CalculateCurrentUsage();
     // We don't check to prune until after we've allocated new space for files,
     // so we should leave a buffer under our target to account for another
     // allocation before the next pruning.
     uint64_t nBuffer = BLOCKFILE_CHUNK_SIZE + UNDOFILE_CHUNK_SIZE;
     uint64_t nBytesToPrune;
     int count = 0;
 
     if (nCurrentUsage + nBuffer >= nPruneTarget) {
         for (int fileNumber = 0; fileNumber < nLastBlockFile; fileNumber++) {
             nBytesToPrune = vinfoBlockFile[fileNumber].nSize +
                             vinfoBlockFile[fileNumber].nUndoSize;
 
             if (vinfoBlockFile[fileNumber].nSize == 0) continue;
 
             if (nCurrentUsage + nBuffer <
                 nPruneTarget) // are we below our target?
                 break;
 
             // don't prune files that could have a block within
             // MIN_BLOCKS_TO_KEEP of the main chain's tip but keep scanning
             if (vinfoBlockFile[fileNumber].nHeightLast > nLastBlockWeCanPrune)
                 continue;
 
             PruneOneBlockFile(fileNumber);
             // Queue up the files for removal
             setFilesToPrune.insert(fileNumber);
             nCurrentUsage -= nBytesToPrune;
             count++;
         }
     }
 
     LogPrint("prune", "Prune: target=%dMiB actual=%dMiB diff=%dMiB "
                       "max_prune_height=%d removed %d blk/rev pairs\n",
              nPruneTarget / 1024 / 1024, nCurrentUsage / 1024 / 1024,
              ((int64_t)nPruneTarget - (int64_t)nCurrentUsage) / 1024 / 1024,
              nLastBlockWeCanPrune, count);
 }
 
 bool CheckDiskSpace(uint64_t nAdditionalBytes) {
     uint64_t nFreeBytesAvailable =
         boost::filesystem::space(GetDataDir()).available;
 
     // Check for nMinDiskSpace bytes (currently 50MB)
     if (nFreeBytesAvailable < nMinDiskSpace + nAdditionalBytes)
         return AbortNode("Disk space is low!", _("Error: Disk space is low!"));
 
     return true;
 }
 
 FILE *OpenDiskFile(const CDiskBlockPos &pos, const char *prefix,
                    bool fReadOnly) {
     if (pos.IsNull()) return nullptr;
     boost::filesystem::path path = GetBlockPosFilename(pos, prefix);
     boost::filesystem::create_directories(path.parent_path());
     FILE *file = fopen(path.string().c_str(), "rb+");
     if (!file && !fReadOnly) file = fopen(path.string().c_str(), "wb+");
     if (!file) {
         LogPrintf("Unable to open file %s\n", path.string());
         return nullptr;
     }
     if (pos.nPos) {
         if (fseek(file, pos.nPos, SEEK_SET)) {
             LogPrintf("Unable to seek to position %u of %s\n", pos.nPos,
                       path.string());
             fclose(file);
             return nullptr;
         }
     }
     return file;
 }
 
 FILE *OpenBlockFile(const CDiskBlockPos &pos, bool fReadOnly) {
     return OpenDiskFile(pos, "blk", fReadOnly);
 }
 
 FILE *OpenUndoFile(const CDiskBlockPos &pos, bool fReadOnly) {
     return OpenDiskFile(pos, "rev", fReadOnly);
 }
 
 boost::filesystem::path GetBlockPosFilename(const CDiskBlockPos &pos,
                                             const char *prefix) {
     return GetDataDir() / "blocks" / strprintf("%s%05u.dat", prefix, pos.nFile);
 }
 
 CBlockIndex *InsertBlockIndex(uint256 hash) {
     if (hash.IsNull()) return nullptr;
 
     // Return existing
     BlockMap::iterator mi = mapBlockIndex.find(hash);
     if (mi != mapBlockIndex.end()) return (*mi).second;
 
     // Create new
     CBlockIndex *pindexNew = new CBlockIndex();
     if (!pindexNew)
         throw std::runtime_error(std::string(__func__) +
                                  ": new CBlockIndex failed");
     mi = mapBlockIndex.insert(std::make_pair(hash, pindexNew)).first;
     pindexNew->phashBlock = &((*mi).first);
 
     return pindexNew;
 }
 
 bool static LoadBlockIndexDB(const CChainParams &chainparams) {
     if (!pblocktree->LoadBlockIndexGuts(InsertBlockIndex)) return false;
 
     boost::this_thread::interruption_point();
 
     // Calculate nChainWork
     std::vector<std::pair<int, CBlockIndex *>> vSortedByHeight;
     vSortedByHeight.reserve(mapBlockIndex.size());
     for (const std::pair<uint256, CBlockIndex *> &item : mapBlockIndex) {
         CBlockIndex *pindex = item.second;
         vSortedByHeight.push_back(std::make_pair(pindex->nHeight, pindex));
     }
     sort(vSortedByHeight.begin(), vSortedByHeight.end());
     for (const std::pair<int, CBlockIndex *> &item : vSortedByHeight) {
         CBlockIndex *pindex = item.second;
         pindex->nChainWork = (pindex->pprev ? pindex->pprev->nChainWork : 0) +
                              GetBlockProof(*pindex);
         pindex->nTimeMax =
             (pindex->pprev ? std::max(pindex->pprev->nTimeMax, pindex->nTime)
                            : pindex->nTime);
         // We can link the chain of blocks for which we've received transactions
         // at some point. Pruned nodes may have deleted the block.
         if (pindex->nTx > 0) {
             if (pindex->pprev) {
                 if (pindex->pprev->nChainTx) {
                     pindex->nChainTx = pindex->pprev->nChainTx + pindex->nTx;
                 } else {
                     pindex->nChainTx = 0;
                     mapBlocksUnlinked.insert(
                         std::make_pair(pindex->pprev, pindex));
                 }
             } else {
                 pindex->nChainTx = pindex->nTx;
             }
         }
         if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS) &&
             (pindex->nChainTx || pindex->pprev == nullptr))
             setBlockIndexCandidates.insert(pindex);
         if (pindex->nStatus & BLOCK_FAILED_MASK &&
             (!pindexBestInvalid ||
              pindex->nChainWork > pindexBestInvalid->nChainWork))
             pindexBestInvalid = pindex;
         if (pindex->pprev) pindex->BuildSkip();
         if (pindex->IsValid(BLOCK_VALID_TREE) &&
             (pindexBestHeader == nullptr ||
              CBlockIndexWorkComparator()(pindexBestHeader, pindex)))
             pindexBestHeader = pindex;
     }
 
     // Load block file info
     pblocktree->ReadLastBlockFile(nLastBlockFile);
     vinfoBlockFile.resize(nLastBlockFile + 1);
     LogPrintf("%s: last block file = %i\n", __func__, nLastBlockFile);
     for (int nFile = 0; nFile <= nLastBlockFile; nFile++) {
         pblocktree->ReadBlockFileInfo(nFile, vinfoBlockFile[nFile]);
     }
     LogPrintf("%s: last block file info: %s\n", __func__,
               vinfoBlockFile[nLastBlockFile].ToString());
     for (int nFile = nLastBlockFile + 1; true; nFile++) {
         CBlockFileInfo info;
         if (pblocktree->ReadBlockFileInfo(nFile, info)) {
             vinfoBlockFile.push_back(info);
         } else {
             break;
         }
     }
 
     // Check presence of blk files
     LogPrintf("Checking all blk files are present...\n");
     std::set<int> setBlkDataFiles;
     for (const std::pair<uint256, CBlockIndex *> &item : mapBlockIndex) {
         CBlockIndex *pindex = item.second;
         if (pindex->nStatus & BLOCK_HAVE_DATA) {
             setBlkDataFiles.insert(pindex->nFile);
         }
     }
     for (std::set<int>::iterator it = setBlkDataFiles.begin();
          it != setBlkDataFiles.end(); it++) {
         CDiskBlockPos pos(*it, 0);
         if (CAutoFile(OpenBlockFile(pos, true), SER_DISK, CLIENT_VERSION)
                 .IsNull()) {
             return false;
         }
     }
 
     // Check whether we have ever pruned block & undo files
     pblocktree->ReadFlag("prunedblockfiles", fHavePruned);
     if (fHavePruned)
         LogPrintf(
             "LoadBlockIndexDB(): Block files have previously been pruned\n");
 
     // Check whether we need to continue reindexing
     bool fReindexing = false;
     pblocktree->ReadReindexing(fReindexing);
     fReindex |= fReindexing;
 
     // Check whether we have a transaction index
     pblocktree->ReadFlag("txindex", fTxIndex);
     LogPrintf("%s: transaction index %s\n", __func__,
               fTxIndex ? "enabled" : "disabled");
 
     // Load pointer to end of best chain
     BlockMap::iterator it = mapBlockIndex.find(pcoinsTip->GetBestBlock());
     if (it == mapBlockIndex.end()) return true;
     chainActive.SetTip(it->second);
 
     PruneBlockIndexCandidates();
 
     LogPrintf(
         "%s: hashBestChain=%s height=%d date=%s progress=%f\n", __func__,
         chainActive.Tip()->GetBlockHash().ToString(), chainActive.Height(),
         DateTimeStrFormat("%Y-%m-%d %H:%M:%S",
                           chainActive.Tip()->GetBlockTime()),
         GuessVerificationProgress(chainparams.TxData(), chainActive.Tip()));
 
     return true;
 }
 
 CVerifyDB::CVerifyDB() {
     uiInterface.ShowProgress(_("Verifying blocks..."), 0);
 }
 
 CVerifyDB::~CVerifyDB() {
     uiInterface.ShowProgress("", 100);
 }
 
 bool CVerifyDB::VerifyDB(const Config &config, const CChainParams &chainparams,
                          CCoinsView *coinsview, int nCheckLevel,
                          int nCheckDepth) {
     LOCK(cs_main);
     if (chainActive.Tip() == nullptr || chainActive.Tip()->pprev == nullptr)
         return true;
 
     // Verify blocks in the best chain
     if (nCheckDepth <= 0)
         nCheckDepth = 1000000000; // suffices until the year 19000
     if (nCheckDepth > chainActive.Height()) nCheckDepth = chainActive.Height();
     nCheckLevel = std::max(0, std::min(4, nCheckLevel));
     LogPrintf("Verifying last %i blocks at level %i\n", nCheckDepth,
               nCheckLevel);
     CCoinsViewCache coins(coinsview);
     CBlockIndex *pindexState = chainActive.Tip();
     CBlockIndex *pindexFailure = nullptr;
     int nGoodTransactions = 0;
     CValidationState state;
     int reportDone = 0;
     LogPrintf("[0%%]...");
     for (CBlockIndex *pindex = chainActive.Tip(); pindex && pindex->pprev;
          pindex = pindex->pprev) {
         boost::this_thread::interruption_point();
         int percentageDone = std::max(
             1, std::min(
                    99,
                    (int)(((double)(chainActive.Height() - pindex->nHeight)) /
                          (double)nCheckDepth * (nCheckLevel >= 4 ? 50 : 100))));
         if (reportDone < percentageDone / 10) {
             // report every 10% step
             LogPrintf("[%d%%]...", percentageDone);
             reportDone = percentageDone / 10;
         }
         uiInterface.ShowProgress(_("Verifying blocks..."), percentageDone);
         if (pindex->nHeight < chainActive.Height() - nCheckDepth) break;
         if (fPruneMode && !(pindex->nStatus & BLOCK_HAVE_DATA)) {
             // If pruning, only go back as far as we have data.
             LogPrintf("VerifyDB(): block verification stopping at height %d "
                       "(pruning, no data)\n",
                       pindex->nHeight);
             break;
         }
         CBlock block;
         // check level 0: read from disk
         if (!ReadBlockFromDisk(block, pindex, chainparams.GetConsensus()))
             return error(
                 "VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s",
                 pindex->nHeight, pindex->GetBlockHash().ToString());
         // check level 1: verify block validity
         if (nCheckLevel >= 1 &&
             !CheckBlock(config, block, state, chainparams.GetConsensus()))
             return error("%s: *** found bad block at %d, hash=%s (%s)\n",
                          __func__, pindex->nHeight,
                          pindex->GetBlockHash().ToString(),
                          FormatStateMessage(state));
         // check level 2: verify undo validity
         if (nCheckLevel >= 2 && pindex) {
             CBlockUndo undo;
             CDiskBlockPos pos = pindex->GetUndoPos();
             if (!pos.IsNull()) {
                 if (!UndoReadFromDisk(undo, pos, pindex->pprev->GetBlockHash()))
                     return error(
                         "VerifyDB(): *** found bad undo data at %d, hash=%s\n",
                         pindex->nHeight, pindex->GetBlockHash().ToString());
             }
         }
         // check level 3: check for inconsistencies during memory-only
         // disconnect of tip blocks
         if (nCheckLevel >= 3 && pindex == pindexState &&
             (coins.DynamicMemoryUsage() + pcoinsTip->DynamicMemoryUsage()) <=
                 nCoinCacheUsage) {
             bool fClean = true;
             if (!DisconnectBlock(block, state, pindex, coins, &fClean))
                 return error("VerifyDB(): *** irrecoverable inconsistency in "
                              "block data at %d, hash=%s",
                              pindex->nHeight,
                              pindex->GetBlockHash().ToString());
             pindexState = pindex->pprev;
             if (!fClean) {
                 nGoodTransactions = 0;
                 pindexFailure = pindex;
             } else
                 nGoodTransactions += block.vtx.size();
         }
         if (ShutdownRequested()) return true;
     }
     if (pindexFailure)
         return error("VerifyDB(): *** coin database inconsistencies found "
                      "(last %i blocks, %i good transactions before that)\n",
                      chainActive.Height() - pindexFailure->nHeight + 1,
                      nGoodTransactions);
 
     // check level 4: try reconnecting blocks
     if (nCheckLevel >= 4) {
         CBlockIndex *pindex = pindexState;
         while (pindex != chainActive.Tip()) {
             boost::this_thread::interruption_point();
             uiInterface.ShowProgress(
                 _("Verifying blocks..."),
                 std::max(
                     1, std::min(99, 100 - (int)(((double)(chainActive.Height() -
                                                           pindex->nHeight)) /
                                                 (double)nCheckDepth * 50))));
             pindex = chainActive.Next(pindex);
             CBlock block;
             if (!ReadBlockFromDisk(block, pindex, chainparams.GetConsensus()))
                 return error(
                     "VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s",
                     pindex->nHeight, pindex->GetBlockHash().ToString());
             if (!ConnectBlock(config, block, state, pindex, coins, chainparams))
                 return error(
                     "VerifyDB(): *** found unconnectable block at %d, hash=%s",
                     pindex->nHeight, pindex->GetBlockHash().ToString());
         }
     }
 
     LogPrintf("[DONE].\n");
     LogPrintf("No coin database inconsistencies in last %i blocks (%i "
               "transactions)\n",
               chainActive.Height() - pindexState->nHeight, nGoodTransactions);
 
     return true;
 }
 
 bool RewindBlockIndex(const Config &config, const CChainParams &params) {
     LOCK(cs_main);
 
     int nHeight = chainActive.Height() + 1;
 
     // nHeight is now the height of the first insufficiently-validated block, or
     // tipheight + 1
     CValidationState state;
     CBlockIndex *pindex = chainActive.Tip();
     while (chainActive.Height() >= nHeight) {
         if (fPruneMode && !(chainActive.Tip()->nStatus & BLOCK_HAVE_DATA)) {
             // If pruning, don't try rewinding past the HAVE_DATA point; since
             // older blocks can't be served anyway, there's no need to walk
             // further, and trying to DisconnectTip() will fail (and require a
             // needless reindex/redownload of the blockchain).
             break;
         }
         if (!DisconnectTip(config, state, true)) {
             return error(
                 "RewindBlockIndex: unable to disconnect block at height %i",
                 pindex->nHeight);
         }
         // Occasionally flush state to disk.
         if (!FlushStateToDisk(state, FLUSH_STATE_PERIODIC)) return false;
     }
 
     // Reduce validity flag and have-data flags.
     // We do this after actual disconnecting, otherwise we'll end up writing the
     // lack of data to disk before writing the chainstate, resulting in a
     // failure to continue if interrupted.
     for (BlockMap::iterator it = mapBlockIndex.begin();
          it != mapBlockIndex.end(); it++) {
         CBlockIndex *pindexIter = it->second;
 
         if (pindexIter->IsValid(BLOCK_VALID_TRANSACTIONS) &&
             pindexIter->nChainTx) {
             setBlockIndexCandidates.insert(pindexIter);
         }
     }
 
     PruneBlockIndexCandidates();
 
     CheckBlockIndex(params.GetConsensus());
 
     if (!FlushStateToDisk(state, FLUSH_STATE_ALWAYS)) {
         return false;
     }
 
     return true;
 }
 
 // May NOT be used after any connections are up as much of the peer-processing
 // logic assumes a consistent block index state
 void UnloadBlockIndex() {
     LOCK(cs_main);
     setBlockIndexCandidates.clear();
     chainActive.SetTip(nullptr);
     pindexBestInvalid = nullptr;
     pindexBestHeader = nullptr;
     mempool.clear();
     mapBlocksUnlinked.clear();
     vinfoBlockFile.clear();
     nLastBlockFile = 0;
     nBlockSequenceId = 1;
     setDirtyBlockIndex.clear();
     setDirtyFileInfo.clear();
     versionbitscache.Clear();
     for (int b = 0; b < VERSIONBITS_NUM_BITS; b++) {
         warningcache[b].clear();
     }
 
     for (BlockMap::value_type &entry : mapBlockIndex) {
         delete entry.second;
     }
     mapBlockIndex.clear();
     fHavePruned = false;
 }
 
 bool LoadBlockIndex(const CChainParams &chainparams) {
     // Load block index from databases
     if (!fReindex && !LoadBlockIndexDB(chainparams)) return false;
     return true;
 }
 
 bool InitBlockIndex(const Config &config) {
     LOCK(cs_main);
 
     // Check whether we're already initialized
     if (chainActive.Genesis() != nullptr) return true;
 
     // Use the provided setting for -txindex in the new database
     fTxIndex = GetBoolArg("-txindex", DEFAULT_TXINDEX);
     pblocktree->WriteFlag("txindex", fTxIndex);
     LogPrintf("Initializing databases...\n");
 
     // Only add the genesis block if not reindexing (in which case we reuse the
     // one already on disk)
     if (!fReindex) {
         try {
             const CChainParams &chainparams = config.GetChainParams();
             CBlock &block = const_cast<CBlock &>(chainparams.GenesisBlock());
             // Start new block file
             unsigned int nBlockSize =
                 ::GetSerializeSize(block, SER_DISK, CLIENT_VERSION);
             CDiskBlockPos blockPos;
             CValidationState state;
             if (!FindBlockPos(state, blockPos, nBlockSize + 8, 0,
                               block.GetBlockTime()))
                 return error("LoadBlockIndex(): FindBlockPos failed");
             if (!WriteBlockToDisk(block, blockPos, chainparams.MessageStart()))
                 return error(
                     "LoadBlockIndex(): writing genesis block to disk failed");
             CBlockIndex *pindex = AddToBlockIndex(block);
             if (!ReceivedBlockTransactions(block, state, pindex, blockPos))
                 return error("LoadBlockIndex(): genesis block not accepted");
             // Force a chainstate write so that when we VerifyDB in a moment, it
             // doesn't check stale data
             return FlushStateToDisk(state, FLUSH_STATE_ALWAYS);
         } catch (const std::runtime_error &e) {
             return error(
                 "LoadBlockIndex(): failed to initialize block database: %s",
                 e.what());
         }
     }
 
     return true;
 }
 
 bool LoadExternalBlockFile(const Config &config, FILE *fileIn,
                            CDiskBlockPos *dbp) {
     // Map of disk positions for blocks with unknown parent (only used for
     // reindex)
     static std::multimap<uint256, CDiskBlockPos> mapBlocksUnknownParent;
     int64_t nStart = GetTimeMillis();
 
     const CChainParams &chainparams = config.GetChainParams();
 
     int nLoaded = 0;
     try {
         // This takes over fileIn and calls fclose() on it in the CBufferedFile
         // destructor. Make sure we have at least 2*MAX_TX_SIZE space in there
         // so any transaction can fit in the buffer.
         CBufferedFile blkdat(fileIn, 2 * MAX_TX_SIZE, MAX_TX_SIZE + 8, SER_DISK,
                              CLIENT_VERSION);
         uint64_t nRewind = blkdat.GetPos();
         while (!blkdat.eof()) {
             boost::this_thread::interruption_point();
 
             blkdat.SetPos(nRewind);
             // Start one byte further next time, in case of failure.
             nRewind++;
             // Remove former limit.
             blkdat.SetLimit();
             unsigned int nSize = 0;
             try {
                 // Locate a header.
                 unsigned char buf[CMessageHeader::MESSAGE_START_SIZE];
                 blkdat.FindByte(chainparams.MessageStart()[0]);
                 nRewind = blkdat.GetPos() + 1;
                 blkdat >> FLATDATA(buf);
                 if (memcmp(buf, chainparams.MessageStart(),
                            CMessageHeader::MESSAGE_START_SIZE))
                     continue;
                 // Read size.
                 blkdat >> nSize;
                 if (nSize < 80) continue;
             } catch (const std::exception &) {
                 // No valid block header found; don't complain.
                 break;
             }
             try {
                 // read block
                 uint64_t nBlockPos = blkdat.GetPos();
                 if (dbp) dbp->nPos = nBlockPos;
                 blkdat.SetLimit(nBlockPos + nSize);
                 blkdat.SetPos(nBlockPos);
                 std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
                 CBlock &block = *pblock;
                 blkdat >> block;
                 nRewind = blkdat.GetPos();
 
                 // detect out of order blocks, and store them for later
                 uint256 hash = block.GetHash();
                 if (hash != chainparams.GetConsensus().hashGenesisBlock &&
                     mapBlockIndex.find(block.hashPrevBlock) ==
                         mapBlockIndex.end()) {
                     LogPrint("reindex",
                              "%s: Out of order block %s, parent %s not known\n",
                              __func__, hash.ToString(),
                              block.hashPrevBlock.ToString());
                     if (dbp)
                         mapBlocksUnknownParent.insert(
                             std::make_pair(block.hashPrevBlock, *dbp));
                     continue;
                 }
 
                 // process in case the block isn't known yet
                 if (mapBlockIndex.count(hash) == 0 ||
                     (mapBlockIndex[hash]->nStatus & BLOCK_HAVE_DATA) == 0) {
                     LOCK(cs_main);
                     CValidationState state;
                     if (AcceptBlock(config, pblock, state, nullptr, true, dbp,
                                     nullptr))
                         nLoaded++;
                     if (state.IsError()) break;
                 } else if (hash !=
                                chainparams.GetConsensus().hashGenesisBlock &&
                            mapBlockIndex[hash]->nHeight % 1000 == 0) {
                     LogPrint(
                         "reindex",
                         "Block Import: already had block %s at height %d\n",
                         hash.ToString(), mapBlockIndex[hash]->nHeight);
                 }
 
                 // Activate the genesis block so normal node progress can
                 // continue
                 if (hash == chainparams.GetConsensus().hashGenesisBlock) {
                     CValidationState state;
                     if (!ActivateBestChain(config, state)) {
                         break;
                     }
                 }
 
                 NotifyHeaderTip();
 
                 // Recursively process earlier encountered successors of this
                 // block
                 std::deque<uint256> queue;
                 queue.push_back(hash);
                 while (!queue.empty()) {
                     uint256 head = queue.front();
                     queue.pop_front();
                     std::pair<std::multimap<uint256, CDiskBlockPos>::iterator,
                               std::multimap<uint256, CDiskBlockPos>::iterator>
                         range = mapBlocksUnknownParent.equal_range(head);
                     while (range.first != range.second) {
                         std::multimap<uint256, CDiskBlockPos>::iterator it =
                             range.first;
                         std::shared_ptr<CBlock> pblockrecursive =
                             std::make_shared<CBlock>();
                         if (ReadBlockFromDisk(*pblockrecursive, it->second,
                                               chainparams.GetConsensus())) {
                             LogPrint(
                                 "reindex",
                                 "%s: Processing out of order child %s of %s\n",
                                 __func__, pblockrecursive->GetHash().ToString(),
                                 head.ToString());
                             LOCK(cs_main);
                             CValidationState dummy;
                             if (AcceptBlock(config, pblockrecursive, dummy,
                                             nullptr, true, &it->second,
                                             nullptr)) {
                                 nLoaded++;
                                 queue.push_back(pblockrecursive->GetHash());
                             }
                         }
                         range.first++;
                         mapBlocksUnknownParent.erase(it);
                         NotifyHeaderTip();
                     }
                 }
             } catch (const std::exception &e) {
                 LogPrintf("%s: Deserialize or I/O error - %s\n", __func__,
                           e.what());
             }
         }
     } catch (const std::runtime_error &e) {
         AbortNode(std::string("System error: ") + e.what());
     }
     if (nLoaded > 0)
         LogPrintf("Loaded %i blocks from external file in %dms\n", nLoaded,
                   GetTimeMillis() - nStart);
     return nLoaded > 0;
 }
 
 void static CheckBlockIndex(const Consensus::Params &consensusParams) {
     if (!fCheckBlockIndex) {
         return;
     }
 
     LOCK(cs_main);
 
     // During a reindex, we read the genesis block and call CheckBlockIndex
     // before ActivateBestChain, so we have the genesis block in mapBlockIndex
     // but no active chain. (A few of the tests when iterating the block tree
     // require that chainActive has been initialized.)
     if (chainActive.Height() < 0) {
         assert(mapBlockIndex.size() <= 1);
         return;
     }
 
     // Build forward-pointing map of the entire block tree.
     std::multimap<CBlockIndex *, CBlockIndex *> forward;
     for (BlockMap::iterator it = mapBlockIndex.begin();
          it != mapBlockIndex.end(); it++) {
         forward.insert(std::make_pair(it->second->pprev, it->second));
     }
 
     assert(forward.size() == mapBlockIndex.size());
 
     std::pair<std::multimap<CBlockIndex *, CBlockIndex *>::iterator,
               std::multimap<CBlockIndex *, CBlockIndex *>::iterator>
         rangeGenesis = forward.equal_range(nullptr);
     CBlockIndex *pindex = rangeGenesis.first->second;
     rangeGenesis.first++;
     // There is only one index entry with parent nullptr.
     assert(rangeGenesis.first == rangeGenesis.second);
 
     // Iterate over the entire block tree, using depth-first search.
     // Along the way, remember whether there are blocks on the path from genesis
     // block being explored which are the first to have certain properties.
     size_t nNodes = 0;
     int nHeight = 0;
     // Oldest ancestor of pindex which is invalid.
     CBlockIndex *pindexFirstInvalid = nullptr;
     // Oldest ancestor of pindex which does not have BLOCK_HAVE_DATA.
     CBlockIndex *pindexFirstMissing = nullptr;
     // Oldest ancestor of pindex for which nTx == 0.
     CBlockIndex *pindexFirstNeverProcessed = nullptr;
     // Oldest ancestor of pindex which does not have BLOCK_VALID_TREE
     // (regardless of being valid or not).
     CBlockIndex *pindexFirstNotTreeValid = nullptr;
     // Oldest ancestor of pindex which does not have BLOCK_VALID_TRANSACTIONS
     // (regardless of being valid or not).
     CBlockIndex *pindexFirstNotTransactionsValid = nullptr;
     // Oldest ancestor of pindex which does not have BLOCK_VALID_CHAIN
     // (regardless of being valid or not).
     CBlockIndex *pindexFirstNotChainValid = nullptr;
     // Oldest ancestor of pindex which does not have BLOCK_VALID_SCRIPTS
     // (regardless of being valid or not).
     CBlockIndex *pindexFirstNotScriptsValid = nullptr;
     while (pindex != nullptr) {
         nNodes++;
         if (pindexFirstInvalid == nullptr &&
             pindex->nStatus & BLOCK_FAILED_VALID)
             pindexFirstInvalid = pindex;
         if (pindexFirstMissing == nullptr &&
             !(pindex->nStatus & BLOCK_HAVE_DATA))
             pindexFirstMissing = pindex;
         if (pindexFirstNeverProcessed == nullptr && pindex->nTx == 0)
             pindexFirstNeverProcessed = pindex;
         if (pindex->pprev != nullptr && pindexFirstNotTreeValid == nullptr &&
             (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TREE)
             pindexFirstNotTreeValid = pindex;
         if (pindex->pprev != nullptr &&
             pindexFirstNotTransactionsValid == nullptr &&
             (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TRANSACTIONS)
             pindexFirstNotTransactionsValid = pindex;
         if (pindex->pprev != nullptr && pindexFirstNotChainValid == nullptr &&
             (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_CHAIN)
             pindexFirstNotChainValid = pindex;
         if (pindex->pprev != nullptr && pindexFirstNotScriptsValid == nullptr &&
             (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_SCRIPTS)
             pindexFirstNotScriptsValid = pindex;
 
         // Begin: actual consistency checks.
         if (pindex->pprev == nullptr) {
             // Genesis block checks.
             // Genesis block's hash must match.
             assert(pindex->GetBlockHash() == consensusParams.hashGenesisBlock);
             // The current active chain's genesis block must be this block.
             assert(pindex == chainActive.Genesis());
         }
         if (pindex->nChainTx == 0) {
             // nSequenceId can't be set positive for blocks that aren't linked
             // (negative is used for preciousblock)
             assert(pindex->nSequenceId <= 0);
         }
         // VALID_TRANSACTIONS is equivalent to nTx > 0 for all nodes (whether or
         // not pruning has occurred). HAVE_DATA is only equivalent to nTx > 0
         // (or VALID_TRANSACTIONS) if no pruning has occurred.
         if (!fHavePruned) {
             // If we've never pruned, then HAVE_DATA should be equivalent to nTx
             // > 0
             assert(!(pindex->nStatus & BLOCK_HAVE_DATA) == (pindex->nTx == 0));
             assert(pindexFirstMissing == pindexFirstNeverProcessed);
         } else {
             // If we have pruned, then we can only say that HAVE_DATA implies
             // nTx > 0
             if (pindex->nStatus & BLOCK_HAVE_DATA) assert(pindex->nTx > 0);
         }
         if (pindex->nStatus & BLOCK_HAVE_UNDO)
             assert(pindex->nStatus & BLOCK_HAVE_DATA);
         // This is pruning-independent.
         assert(((pindex->nStatus & BLOCK_VALID_MASK) >=
                 BLOCK_VALID_TRANSACTIONS) == (pindex->nTx > 0));
         // All parents having had data (at some point) is equivalent to all
         // parents being VALID_TRANSACTIONS, which is equivalent to nChainTx
         // being set.
         // nChainTx != 0 is used to signal that all parent blocks have been
         // processed (but may have been pruned).
         assert((pindexFirstNeverProcessed != nullptr) ==
                (pindex->nChainTx == 0));
         assert((pindexFirstNotTransactionsValid != nullptr) ==
                (pindex->nChainTx == 0));
         // nHeight must be consistent.
         assert(pindex->nHeight == nHeight);
         // For every block except the genesis block, the chainwork must be
         // larger than the parent's.
         assert(pindex->pprev == nullptr ||
                pindex->nChainWork >= pindex->pprev->nChainWork);
         // The pskip pointer must point back for all but the first 2 blocks.
         assert(nHeight < 2 ||
                (pindex->pskip && (pindex->pskip->nHeight < nHeight)));
         // All mapBlockIndex entries must at least be TREE valid
         assert(pindexFirstNotTreeValid == nullptr);
         if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TREE) {
             // TREE valid implies all parents are TREE valid
             assert(pindexFirstNotTreeValid == nullptr);
         }
         if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_CHAIN) {
             // CHAIN valid implies all parents are CHAIN valid
             assert(pindexFirstNotChainValid == nullptr);
         }
         if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_SCRIPTS) {
             // SCRIPTS valid implies all parents are SCRIPTS valid
             assert(pindexFirstNotScriptsValid == nullptr);
         }
         if (pindexFirstInvalid == nullptr) {
             // Checks for not-invalid blocks.
             // The failed mask cannot be set for blocks without invalid parents.
             assert((pindex->nStatus & BLOCK_FAILED_MASK) == 0);
         }
         if (!CBlockIndexWorkComparator()(pindex, chainActive.Tip()) &&
             pindexFirstNeverProcessed == nullptr) {
             if (pindexFirstInvalid == nullptr) {
                 // If this block sorts at least as good as the current tip and
                 // is valid and we have all data for its parents, it must be in
                 // setBlockIndexCandidates. chainActive.Tip() must also be there
                 // even if some data has been pruned.
                 if (pindexFirstMissing == nullptr ||
                     pindex == chainActive.Tip()) {
                     assert(setBlockIndexCandidates.count(pindex));
                 }
                 // If some parent is missing, then it could be that this block
                 // was in setBlockIndexCandidates but had to be removed because
                 // of the missing data. In this case it must be in
                 // mapBlocksUnlinked -- see test below.
             }
         } else {
             // If this block sorts worse than the current tip or some ancestor's
             // block has never been seen, it cannot be in
             // setBlockIndexCandidates.
             assert(setBlockIndexCandidates.count(pindex) == 0);
         }
         // Check whether this block is in mapBlocksUnlinked.
         std::pair<std::multimap<CBlockIndex *, CBlockIndex *>::iterator,
                   std::multimap<CBlockIndex *, CBlockIndex *>::iterator>
             rangeUnlinked = mapBlocksUnlinked.equal_range(pindex->pprev);
         bool foundInUnlinked = false;
         while (rangeUnlinked.first != rangeUnlinked.second) {
             assert(rangeUnlinked.first->first == pindex->pprev);
             if (rangeUnlinked.first->second == pindex) {
                 foundInUnlinked = true;
                 break;
             }
             rangeUnlinked.first++;
         }
         if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) &&
             pindexFirstNeverProcessed != nullptr &&
             pindexFirstInvalid == nullptr) {
             // If this block has block data available, some parent was never
             // received, and has no invalid parents, it must be in
             // mapBlocksUnlinked.
             assert(foundInUnlinked);
         }
         if (!(pindex->nStatus & BLOCK_HAVE_DATA)) {
             // Can't be in mapBlocksUnlinked if we don't HAVE_DATA
             assert(!foundInUnlinked);
         }
         if (pindexFirstMissing == nullptr) {
             // We aren't missing data for any parent -- cannot be in
             // mapBlocksUnlinked.
             assert(!foundInUnlinked);
         }
         if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) &&
             pindexFirstNeverProcessed == nullptr &&
             pindexFirstMissing != nullptr) {
             // We HAVE_DATA for this block, have received data for all parents
             // at some point, but we're currently missing data for some parent.
             // We must have pruned.
             assert(fHavePruned);
             // This block may have entered mapBlocksUnlinked if:
             //  - it has a descendant that at some point had more work than the
             //    tip, and
             //  - we tried switching to that descendant but were missing
             //    data for some intermediate block between chainActive and the
             //    tip.
             // So if this block is itself better than chainActive.Tip() and it
             // wasn't in
             // setBlockIndexCandidates, then it must be in mapBlocksUnlinked.
             if (!CBlockIndexWorkComparator()(pindex, chainActive.Tip()) &&
                 setBlockIndexCandidates.count(pindex) == 0) {
                 if (pindexFirstInvalid == nullptr) {
                     assert(foundInUnlinked);
                 }
             }
         }
         // assert(pindex->GetBlockHash() == pindex->GetBlockHeader().GetHash());
         // // Perhaps too slow
         // End: actual consistency checks.
 
         // Try descending into the first subnode.
         std::pair<std::multimap<CBlockIndex *, CBlockIndex *>::iterator,
                   std::multimap<CBlockIndex *, CBlockIndex *>::iterator>
             range = forward.equal_range(pindex);
         if (range.first != range.second) {
             // A subnode was found.
             pindex = range.first->second;
             nHeight++;
             continue;
         }
         // This is a leaf node. Move upwards until we reach a node of which we
         // have not yet visited the last child.
         while (pindex) {
             // We are going to either move to a parent or a sibling of pindex.
             // If pindex was the first with a certain property, unset the
             // corresponding variable.
             if (pindex == pindexFirstInvalid) pindexFirstInvalid = nullptr;
             if (pindex == pindexFirstMissing) pindexFirstMissing = nullptr;
             if (pindex == pindexFirstNeverProcessed)
                 pindexFirstNeverProcessed = nullptr;
             if (pindex == pindexFirstNotTreeValid)
                 pindexFirstNotTreeValid = nullptr;
             if (pindex == pindexFirstNotTransactionsValid)
                 pindexFirstNotTransactionsValid = nullptr;
             if (pindex == pindexFirstNotChainValid)
                 pindexFirstNotChainValid = nullptr;
             if (pindex == pindexFirstNotScriptsValid)
                 pindexFirstNotScriptsValid = nullptr;
             // Find our parent.
             CBlockIndex *pindexPar = pindex->pprev;
             // Find which child we just visited.
             std::pair<std::multimap<CBlockIndex *, CBlockIndex *>::iterator,
                       std::multimap<CBlockIndex *, CBlockIndex *>::iterator>
                 rangePar = forward.equal_range(pindexPar);
             while (rangePar.first->second != pindex) {
                 // Our parent must have at least the node we're coming from as
                 // child.
                 assert(rangePar.first != rangePar.second);
                 rangePar.first++;
             }
             // Proceed to the next one.
             rangePar.first++;
             if (rangePar.first != rangePar.second) {
                 // Move to the sibling.
                 pindex = rangePar.first->second;
                 break;
             } else {
                 // Move up further.
                 pindex = pindexPar;
                 nHeight--;
                 continue;
             }
         }
     }
 
     // Check that we actually traversed the entire map.
     assert(nNodes == forward.size());
 }
 
 std::string CBlockFileInfo::ToString() const {
     return strprintf(
         "CBlockFileInfo(blocks=%u, size=%u, heights=%u...%u, time=%s...%s)",
         nBlocks, nSize, nHeightFirst, nHeightLast,
         DateTimeStrFormat("%Y-%m-%d", nTimeFirst),
         DateTimeStrFormat("%Y-%m-%d", nTimeLast));
 }
 
 CBlockFileInfo *GetBlockFileInfo(size_t n) {
     return &vinfoBlockFile.at(n);
 }
 
 ThresholdState VersionBitsTipState(const Consensus::Params &params,
                                    Consensus::DeploymentPos pos) {
     LOCK(cs_main);
     return VersionBitsState(chainActive.Tip(), params, pos, versionbitscache);
 }
 
 int VersionBitsTipStateSinceHeight(const Consensus::Params &params,
                                    Consensus::DeploymentPos pos) {
     LOCK(cs_main);
     return VersionBitsStateSinceHeight(chainActive.Tip(), params, pos,
                                        versionbitscache);
 }
 
 static const uint64_t MEMPOOL_DUMP_VERSION = 1;
 
 bool LoadMempool(const Config &config) {
     int64_t nExpiryTimeout =
         GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60;
     FILE *filestr =
         fopen((GetDataDir() / "mempool.dat").string().c_str(), "rb");
     CAutoFile file(filestr, SER_DISK, CLIENT_VERSION);
     if (file.IsNull()) {
         LogPrintf(
             "Failed to open mempool file from disk. Continuing anyway.\n");
         return false;
     }
 
     int64_t count = 0;
     int64_t skipped = 0;
     int64_t failed = 0;
     int64_t nNow = GetTime();
 
     try {
         uint64_t version;
         file >> version;
         if (version != MEMPOOL_DUMP_VERSION) {
             return false;
         }
         uint64_t num;
         file >> num;
         double prioritydummy = 0;
         while (num--) {
             CTransactionRef tx;
             int64_t nTime;
             int64_t nFeeDelta;
             file >> tx;
             file >> nTime;
             file >> nFeeDelta;
 
             CAmount amountdelta = nFeeDelta;
             if (amountdelta) {
                 mempool.PrioritiseTransaction(tx->GetId(),
                                               tx->GetId().ToString(),
                                               prioritydummy, amountdelta);
             }
             CValidationState state;
             if (nTime + nExpiryTimeout > nNow) {
                 LOCK(cs_main);
                 AcceptToMemoryPoolWithTime(config, mempool, state, tx, true,
                                            nullptr, nTime);
                 if (state.IsValid()) {
                     ++count;
                 } else {
                     ++failed;
                 }
             } else {
                 ++skipped;
             }
             if (ShutdownRequested()) return false;
         }
         std::map<uint256, CAmount> mapDeltas;
         file >> mapDeltas;
 
         for (const auto &i : mapDeltas) {
             mempool.PrioritiseTransaction(i.first, i.first.ToString(),
                                           prioritydummy, i.second);
         }
     } catch (const std::exception &e) {
         LogPrintf("Failed to deserialize mempool data on disk: %s. Continuing "
                   "anyway.\n",
                   e.what());
         return false;
     }
 
     LogPrintf("Imported mempool transactions from disk: %i successes, %i "
               "failed, %i expired\n",
               count, failed, skipped);
     return true;
 }
 
 void DumpMempool(void) {
     int64_t start = GetTimeMicros();
 
     std::map<uint256, CAmount> mapDeltas;
     std::vector<TxMempoolInfo> vinfo;
 
     {
         LOCK(mempool.cs);
         for (const auto &i : mempool.mapDeltas) {
             mapDeltas[i.first] = i.second.second;
         }
         vinfo = mempool.infoAll();
     }
 
     int64_t mid = GetTimeMicros();
 
     try {
         FILE *filestr =
             fopen((GetDataDir() / "mempool.dat.new").string().c_str(), "wb");
         if (!filestr) {
             return;
         }
 
         CAutoFile file(filestr, SER_DISK, CLIENT_VERSION);
 
         uint64_t version = MEMPOOL_DUMP_VERSION;
         file << version;
 
         file << (uint64_t)vinfo.size();
         for (const auto &i : vinfo) {
             file << *(i.tx);
             file << (int64_t)i.nTime;
             file << (int64_t)i.nFeeDelta;
             mapDeltas.erase(i.tx->GetId());
         }
 
         file << mapDeltas;
         FileCommit(file.Get());
         file.fclose();
         RenameOver(GetDataDir() / "mempool.dat.new",
                    GetDataDir() / "mempool.dat");
         int64_t last = GetTimeMicros();
         LogPrintf("Dumped mempool: %gs to copy, %gs to dump\n",
                   (mid - start) * 0.000001, (last - mid) * 0.000001);
     } catch (const std::exception &e) {
         LogPrintf("Failed to dump mempool: %s. Continuing anyway.\n", e.what());
     }
 }
 
 //! Guess how far we are in the verification process at the given block index
 double GuessVerificationProgress(const ChainTxData &data, CBlockIndex *pindex) {
     if (pindex == nullptr) return 0.0;
 
     int64_t nNow = time(nullptr);
 
     double fTxTotal;
 
     if (pindex->nChainTx <= data.nTxCount) {
         fTxTotal = data.nTxCount + (nNow - data.nTime) * data.dTxRate;
     } else {
         fTxTotal =
             pindex->nChainTx + (nNow - pindex->GetBlockTime()) * data.dTxRate;
     }
 
     return pindex->nChainTx / fTxTotal;
 }
 
 class CMainCleanup {
 public:
     CMainCleanup() {}
     ~CMainCleanup() {
         // block headers
         BlockMap::iterator it1 = mapBlockIndex.begin();
         for (; it1 != mapBlockIndex.end(); it1++)
             delete (*it1).second;
         mapBlockIndex.clear();
     }
 } instance_of_cmaincleanup;