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	diff --git a/src/checkqueue.h b/src/checkqueue.h
	index f0f46fa45..b8ab4ba23 100644
	--- a/src/checkqueue.h
	+++ b/src/checkqueue.h
	@@ -1,211 +1,252 @@
	// Copyright (c) 2012-2018 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_CHECKQUEUE_H
	#define BITCOIN_CHECKQUEUE_H

	#include <sync.h>
	+#include <tinyformat.h>
	+#include <util/threadnames.h>

	#include <algorithm>
	#include <vector>

	#include <boost/thread/condition_variable.hpp>
	#include <boost/thread/mutex.hpp>

	template <typename T> class CCheckQueueControl;

	/**
	* Queue for verifications that have to be performed.
	* The verifications are represented by a type T, which must provide an
	* operator(), returning a bool.
	*
	* One thread (the master) is assumed to push batches of verifications onto the
	* queue, where they are processed by N-1 worker threads. When the master is
	* done adding work, it temporarily joins the worker pool as an N'th worker,
	* until all jobs are done.
	*/
	template <typename T> class CCheckQueue {
	private:
	//! Mutex to protect the inner state
	boost::mutex mutex;

	//! Worker threads block on this when out of work
	boost::condition_variable condWorker;

	//! Master thread blocks on this when out of work
	boost::condition_variable condMaster;

	//! The queue of elements to be processed.
	//! As the order of booleans doesn't matter, it is used as a LIFO (stack)
	std::vector<T> queue;

	//! The number of workers (including the master) that are idle.
	int nIdle{0};

	//! The total number of workers (including the master).
	int nTotal{0};

	//! The temporary evaluation result.
	bool fAllOk{true};

	/**
	* Number of verifications that haven't completed yet.
	* This includes elements that are no longer queued, but still in the
	* worker's own batches.
	*/
	unsigned int nTodo{0};

	//! The maximum number of elements to be processed in one batch
	const unsigned int nBatchSize;

	+ std::vector<std::thread> m_worker_threads;
	+ bool m_request_stop{false};
	+
	/** Internal function that does bulk of the verification work. */
	- bool Loop(bool fMaster = false) {
	+ bool Loop(bool fMaster) {
	boost::condition_variable &cond = fMaster ? condMaster : condWorker;
	std::vector<T> vChecks;
	vChecks.reserve(nBatchSize);
	unsigned int nNow = 0;
	bool fOk = true;
	do {
	{
	boost::unique_lock<boost::mutex> lock(mutex);
	// first do the clean-up of the previous loop run (allowing us
	// to do it in the same critsect)
	if (nNow) {
	fAllOk &= fOk;
	nTodo -= nNow;
	if (nTodo == 0 && !fMaster) {
	// We processed the last element; inform the master it
	// can exit and return the result
	condMaster.notify_one();
	}
	} else {
	// first iteration
	nTotal++;
	}
	// logically, the do loop starts here
	- while (queue.empty()) {
	+ while (queue.empty() && !m_request_stop) {
	if (fMaster && nTodo == 0) {
	nTotal--;
	bool fRet = fAllOk;
	// reset the status for new work later
	fAllOk = true;
	// return the current status
	return fRet;
	}
	nIdle++;
	cond.wait(lock); // wait
	nIdle--;
	}
	+ if (m_request_stop) {
	+ return false;
	+ }
	+
	// Decide how many work units to process now.
	// * Do not try to do everything at once, but aim for
	// increasingly smaller batches so all workers finish
	// approximately simultaneously.
	// * Try to account for idle jobs which will instantly start
	// helping.
	// * Don't do batches smaller than 1 (duh), or larger than
	// nBatchSize.
	nNow = std::max(
	1U, std::min(nBatchSize, (unsigned int)queue.size() /
	(nTotal + nIdle + 1)));
	vChecks.resize(nNow);
	for (unsigned int i = 0; i < nNow; i++) {
	// We want the lock on the mutex to be as short as possible,
	// so swap jobs from the global queue to the local batch
	// vector instead of copying.
	vChecks[i].swap(queue.back());
	queue.pop_back();
	}
	// Check whether we need to do work at all
	fOk = fAllOk;
	}
	// execute work
	for (T &check : vChecks) {
	if (fOk) {
	fOk = check();
	}
	}
	vChecks.clear();
	} while (true);
	}

	public:
	//! Mutex to ensure only one concurrent CCheckQueueControl
	boost::mutex ControlMutex;

	//! Create a new check queue
	explicit CCheckQueue(unsigned int nBatchSizeIn)
	: nBatchSize(nBatchSizeIn) {}

	+ //! Create a pool of new worker threads.
	+ void StartWorkerThreads(const int threads_num) {
	+ {
	+ boost::unique_lock<boost::mutex> lock(mutex);
	+ nIdle = 0;
	+ nTotal = 0;
	+ fAllOk = true;
	+ }
	+ assert(m_worker_threads.empty());
	+ for (int n = 0; n < threads_num; ++n) {
	+ m_worker_threads.emplace_back([this, n]() {
	+ util::ThreadRename(strprintf("scriptch.%i", n));
	+ Loop(false /* worker thread */);
	+ });
	+ }
	+ }
	+
	//! Worker thread
	- void Thread() { Loop(); }
	+ void Thread() { Loop(false /* worker thread */); }

	//! Wait until execution finishes, and return whether all evaluations were
	//! successful.
	- bool Wait() { return Loop(true); }
	+ bool Wait() { return Loop(true /* master thread */); }

	//! Add a batch of checks to the queue
	void Add(std::vector<T> &vChecks) {
	boost::unique_lock<boost::mutex> lock(mutex);
	for (T &check : vChecks) {
	queue.push_back(T());
	check.swap(queue.back());
	}
	nTodo += vChecks.size();
	if (vChecks.size() == 1) {
	condWorker.notify_one();
	} else if (vChecks.size() > 1) {
	condWorker.notify_all();
	}
	}

	- ~CCheckQueue() {}
	+ //! Stop all of the worker threads.
	+ void StopWorkerThreads() {
	+ {
	+ boost::unique_lock<boost::mutex> lock(mutex);
	+ m_request_stop = true;
	+ }
	+ condWorker.notify_all();
	+ for (std::thread &t : m_worker_threads) {
	+ t.join();
	+ }
	+ m_worker_threads.clear();
	+ boost::unique_lock<boost::mutex> lock(mutex);
	+ m_request_stop = false;
	+ }
	+
	+ ~CCheckQueue() { assert(m_worker_threads.empty()); }
	};

	/**
	* RAII-style controller object for a CCheckQueue that guarantees the passed
	* queue is finished before continuing.
	*/
	template <typename T> class CCheckQueueControl {
	private:
	CCheckQueue<T> *const pqueue;
	bool fDone;

	public:
	CCheckQueueControl() = delete;
	CCheckQueueControl(const CCheckQueueControl &) = delete;
	CCheckQueueControl &operator=(const CCheckQueueControl &) = delete;
	explicit CCheckQueueControl(CCheckQueue<T> *const pqueueIn)
	: pqueue(pqueueIn), fDone(false) {
	// passed queue is supposed to be unused, or nullptr
	if (pqueue != nullptr) {
	ENTER_CRITICAL_SECTION(pqueue->ControlMutex);
	}
	}

	bool Wait() {
	if (pqueue == nullptr) {
	return true;
	}
	bool fRet = pqueue->Wait();
	fDone = true;
	return fRet;
	}

	void Add(std::vector<T> &vChecks) {
	if (pqueue != nullptr) {
	pqueue->Add(vChecks);
	}
	}

	~CCheckQueueControl() {
	if (!fDone) {
	Wait();
	}
	if (pqueue != nullptr) {
	LEAVE_CRITICAL_SECTION(pqueue->ControlMutex);
	}
	}
	};

	#endif // BITCOIN_CHECKQUEUE_H
	diff --git a/src/init.cpp b/src/init.cpp
	index e4d26f742..1e13231e8 100644
	--- a/src/init.cpp
	+++ b/src/init.cpp
	@@ -1,3115 +1,3114 @@
	// Copyright (c) 2009-2010 Satoshi Nakamoto
	// Copyright (c) 2009-2018 The Bitcoin Core developers
	// Distributed under the MIT software license, see the accompanying
	// file COPYING or http://www.opensource.org/licenses/mit-license.php.

	#if defined(HAVE_CONFIG_H)
	#include <config/bitcoin-config.h>
	#endif

	#include <init.h>

	#include <addrman.h>
	#include <amount.h>
	#include <avalanche/avalanche.h>
	#include <avalanche/processor.h>
	#include <avalanche/proof.h> // For AVALANCHE_LEGACY_PROOF_DEFAULT
	#include <avalanche/validation.h>
	#include <banman.h>
	#include <blockdb.h>
	#include <blockfilter.h>
	#include <chain.h>
	#include <chainparams.h>
	#include <checkpoints.h>
	#include <compat/sanity.h>
	#include <config.h>
	#include <consensus/validation.h>
	#include <currencyunit.h>
	#include <flatfile.h>
	#include <fs.h>
	#include <hash.h>
	#include <httprpc.h>
	#include <httpserver.h>
	#include <index/blockfilterindex.h>
	#include <index/txindex.h>
	#include <interfaces/chain.h>
	#include <interfaces/node.h>
	#include <key.h>
	#include <miner.h>
	#include <net.h>
	#include <net_permissions.h>
	#include <net_processing.h>
	#include <netbase.h>
	#include <network.h>
	#include <node/context.h>
	#include <node/ui_interface.h>
	#include <policy/mempool.h>
	#include <policy/policy.h>
	#include <policy/settings.h>
	#include <rpc/blockchain.h>
	#include <rpc/register.h>
	#include <rpc/server.h>
	#include <rpc/util.h>
	#include <scheduler.h>
	#include <script/scriptcache.h>
	#include <script/sigcache.h>
	#include <script/standard.h>
	#include <shutdown.h>
	#include <sync.h>
	#include <timedata.h>
	#include <torcontrol.h>
	#include <txdb.h>
	#include <txmempool.h>
	#include <util/asmap.h>
	#include <util/check.h>
	#include <util/moneystr.h>
	#include <util/string.h>
	#include <util/threadnames.h>
	#include <util/translation.h>
	#include <validation.h>
	#include <validationinterface.h>
	#include <walletinitinterface.h>

	#include <boost/algorithm/string/replace.hpp>
	#include <boost/signals2/signal.hpp>
	#include <boost/thread/thread.hpp>

	#if ENABLE_ZMQ
	#include <zmq/zmqabstractnotifier.h>
	#include <zmq/zmqnotificationinterface.h>
	#include <zmq/zmqrpc.h>
	#endif

	#ifndef WIN32
	#include <attributes.h>
	#include <cerrno>
	#include <csignal>
	#include <sys/stat.h>
	#endif
	#include <cstdint>
	#include <cstdio>
	#include <functional>
	#include <set>

	static const bool DEFAULT_PROXYRANDOMIZE = true;
	static const bool DEFAULT_REST_ENABLE = false;
	static const bool DEFAULT_STOPAFTERBLOCKIMPORT = false;

	#ifdef WIN32
	// Win32 LevelDB doesn't use filedescriptors, and the ones used for accessing
	// block files don't count towards the fd_set size limit anyway.
	#define MIN_CORE_FILEDESCRIPTORS 0
	#else
	#define MIN_CORE_FILEDESCRIPTORS 150
	#endif

	static const char *DEFAULT_ASMAP_FILENAME = "ip_asn.map";

	/**
	* The PID file facilities.
	*/
	static const char *BITCOIN_PID_FILENAME = "bitcoind.pid";

	static fs::path GetPidFile(const ArgsManager &args) {
	return AbsPathForConfigVal(
	fs::PathFromString(args.GetArg("-pid", BITCOIN_PID_FILENAME)));
	}

	[[nodiscard]] static bool CreatePidFile(const ArgsManager &args) {
	fsbridge::ofstream file{GetPidFile(args)};
	if (file) {
	#ifdef WIN32
	tfm::format(file, "%d\n", GetCurrentProcessId());
	#else
	tfm::format(file, "%d\n", getpid());
	#endif
	return true;
	} else {
	return InitError(strprintf(_("Unable to create the PID file '%s': %s"),
	fs::PathToString(GetPidFile(args)),
	std::strerror(errno)));
	}
	}

	//////////////////////////////////////////////////////////////////////////////
	//
	// Shutdown
	//

	//
	// Thread management and startup/shutdown:
	//
	// The network-processing threads are all part of a thread group created by
	// AppInit() or the Qt main() function.
	//
	// A clean exit happens when StartShutdown() or the SIGTERM signal handler sets
	// fRequestShutdown, which makes main thread's WaitForShutdown() interrupts the
	// thread group.
	// And then, WaitForShutdown() makes all other on-going threads in the thread
	// group join the main thread.
	// Shutdown() is then called to clean up database connections, and stop other
	// threads that should only be stopped after the main network-processing threads
	// have exited.
	//
	// Shutdown for Qt is very similar, only it uses a QTimer to detect
	// ShutdownRequested() getting set, and then does the normal Qt shutdown thing.
	//

	static std::unique_ptr<ECCVerifyHandle> globalVerifyHandle;

	static std::thread g_load_block;

	static boost::thread_group threadGroup;

	void Interrupt(NodeContext &node) {
	InterruptHTTPServer();
	InterruptHTTPRPC();
	InterruptRPC();
	InterruptREST();
	InterruptTorControl();
	InterruptMapPort();
	if (g_avalanche) {
	// Avalanche needs to be stopped before we interrupt the thread group as
	// the scheduler will stop working then.
	g_avalanche->stopEventLoop();
	}
	if (node.connman) {
	node.connman->Interrupt();
	}
	if (g_txindex) {
	g_txindex->Interrupt();
	}
	ForEachBlockFilterIndex([](BlockFilterIndex &index) { index.Interrupt(); });
	}

	void Shutdown(NodeContext &node) {
	static Mutex g_shutdown_mutex;
	TRY_LOCK(g_shutdown_mutex, lock_shutdown);
	if (!lock_shutdown) {
	return;
	}
	LogPrintf("%s: In progress...\n", __func__);
	Assert(node.args);

	/// Note: Shutdown() must be able to handle cases in which initialization
	/// failed part of the way, for example if the data directory was found to
	/// be locked. Be sure that anything that writes files or flushes caches
	/// only does this if the respective module was initialized.
	util::ThreadRename("shutoff");
	if (node.mempool) {
	node.mempool->AddTransactionsUpdated(1);
	}

	StopHTTPRPC();
	StopREST();
	StopRPC();
	StopHTTPServer();
	for (const auto &client : node.chain_clients) {
	client->flush();
	}
	StopMapPort();

	// Because avalanche and the network depend on each other, it is important
	// to shut them down in this order:
	// 1. Stop avalanche event loop.
	// 2. Shutdown network processing.
	// 3. Destroy avalanche::Processor.
	// 4. Destroy CConnman
	if (g_avalanche) {
	g_avalanche->stopEventLoop();
	}

	// Because these depend on each-other, we make sure that neither can be
	// using the other before destroying them.
	if (node.peerman) {
	UnregisterValidationInterface(node.peerman.get());
	}
	// Follow the lock order requirements:
	// * CheckForStaleTipAndEvictPeers locks cs_main before indirectly calling
	// GetExtraFullOutboundCount which locks cs_vNodes.
	// * ProcessMessage locks cs_main and g_cs_orphans before indirectly calling
	// ForEachNode which locks cs_vNodes.
	// * CConnman::Stop calls DeleteNode, which calls FinalizeNode, which locks
	// cs_main and calls EraseOrphansFor, which locks g_cs_orphans.
	//
	// Thus the implicit locking order requirement is:
	// (1) cs_main, (2) g_cs_orphans, (3) cs_vNodes.
	if (node.connman) {
	node.connman->StopThreads();
	LOCK2(::cs_main, ::g_cs_orphans);
	node.connman->StopNodes();
	}

	StopTorControl();

	// After everything has been shut down, but before things get flushed, stop
	// the CScheduler/checkqueue, threadGroup and load block thread.
	if (node.scheduler) {
	node.scheduler->stop();
	}
	if (g_load_block.joinable()) {
	g_load_block.join();
	}
	threadGroup.interrupt_all();
	threadGroup.join_all();
	+ StopScriptCheckWorkerThreads();

	// After the threads that potentially access these pointers have been
	// stopped, destruct and reset all to nullptr.
	node.peerman.reset();

	// Destroy various global instances
	g_avalanche.reset();
	node.connman.reset();
	node.banman.reset();

	if (node.mempool && node.mempool->IsLoaded() &&
	node.args->GetArg("-persistmempool", DEFAULT_PERSIST_MEMPOOL)) {
	DumpMempool(*node.mempool);
	}

	// FlushStateToDisk generates a ChainStateFlushed callback, which we should
	// avoid missing
	if (node.chainman) {
	LOCK(cs_main);
	for (CChainState *chainstate : node.chainman->GetAll()) {
	if (chainstate->CanFlushToDisk()) {
	chainstate->ForceFlushStateToDisk();
	}
	}
	}

	// After there are no more peers/RPC left to give us new data which may
	// generate CValidationInterface callbacks, flush them...
	GetMainSignals().FlushBackgroundCallbacks();

	// Stop and delete all indexes only after flushing background callbacks.
	if (g_txindex) {
	g_txindex->Stop();
	g_txindex.reset();
	}
	ForEachBlockFilterIndex([](BlockFilterIndex &index) { index.Stop(); });
	DestroyAllBlockFilterIndexes();

	// Any future callbacks will be dropped. This should absolutely be safe - if
	// missing a callback results in an unrecoverable situation, unclean
	// shutdown would too. The only reason to do the above flushes is to let the
	// wallet catch up with our current chain to avoid any strange pruning edge
	// cases and make next startup faster by avoiding rescan.

	if (node.chainman) {
	LOCK(cs_main);
	for (CChainState *chainstate : node.chainman->GetAll()) {
	if (chainstate->CanFlushToDisk()) {
	chainstate->ForceFlushStateToDisk();
	chainstate->ResetCoinsViews();
	}
	}
	pblocktree.reset();
	}
	for (const auto &client : node.chain_clients) {
	client->stop();
	}

	#if ENABLE_ZMQ
	if (g_zmq_notification_interface) {
	UnregisterValidationInterface(g_zmq_notification_interface);
	delete g_zmq_notification_interface;
	g_zmq_notification_interface = nullptr;
	}
	#endif

	node.chain_clients.clear();
	UnregisterAllValidationInterfaces();
	GetMainSignals().UnregisterBackgroundSignalScheduler();
	globalVerifyHandle.reset();
	ECC_Stop();
	node.mempool.reset();
	node.chainman = nullptr;
	node.scheduler.reset();

	try {
	if (!fs::remove(GetPidFile(*node.args))) {
	LogPrintf("%s: Unable to remove PID file: File does not exist\n",
	__func__);
	}
	} catch (const fs::filesystem_error &e) {
	LogPrintf("%s: Unable to remove PID file: %s\n", __func__,
	fsbridge::get_filesystem_error_message(e));
	}

	node.args = nullptr;
	LogPrintf("%s: done\n", __func__);
	}

	/**
	* Signal handlers are very limited in what they are allowed to do.
	* The execution context the handler is invoked in is not guaranteed,
	* so we restrict handler operations to just touching variables:
	*/
	#ifndef WIN32
	static void HandleSIGTERM(int) {
	StartShutdown();
	}

	static void HandleSIGHUP(int) {
	LogInstance().m_reopen_file = true;
	}
	#else
	static BOOL WINAPI consoleCtrlHandler(DWORD dwCtrlType) {
	StartShutdown();
	Sleep(INFINITE);
	return true;
	}
	#endif

	#ifndef WIN32
	static void registerSignalHandler(int signal, void (*handler)(int)) {
	struct sigaction sa;
	sa.sa_handler = handler;
	sigemptyset(&sa.sa_mask);
	sa.sa_flags = 0;
	sigaction(signal, &sa, NULL);
	}
	#endif

	static boost::signals2::connection rpc_notify_block_change_connection;
	static void OnRPCStarted() {
	rpc_notify_block_change_connection = uiInterface.NotifyBlockTip_connect(
	std::bind(RPCNotifyBlockChange, std::placeholders::_2));
	}

	static void OnRPCStopped() {
	rpc_notify_block_change_connection.disconnect();
	RPCNotifyBlockChange(nullptr);
	g_best_block_cv.notify_all();
	LogPrint(BCLog::RPC, "RPC stopped.\n");
	}

	void SetupServerArgs(NodeContext &node) {
	assert(!node.args);
	node.args = &gArgs;
	ArgsManager &argsman = *node.args;

	SetupHelpOptions(argsman);
	SetupCurrencyUnitOptions(argsman);
	// server-only for now
	argsman.AddArg("-help-debug",
	"Print help message with debugging options and exit", false,
	OptionsCategory::DEBUG_TEST);

	const auto defaultBaseParams =
	CreateBaseChainParams(CBaseChainParams::MAIN);
	const auto testnetBaseParams =
	CreateBaseChainParams(CBaseChainParams::TESTNET);
	const auto regtestBaseParams =
	CreateBaseChainParams(CBaseChainParams::REGTEST);
	const auto defaultChainParams = CreateChainParams(CBaseChainParams::MAIN);
	const auto testnetChainParams =
	CreateChainParams(CBaseChainParams::TESTNET);
	const auto regtestChainParams =
	CreateChainParams(CBaseChainParams::REGTEST);

	// Hidden Options
	std::vector<std::string> hidden_args = {
	"-dbcrashratio", "-forcecompactdb", "-maxaddrtosend", "-parkdeepreorg",
	"-automaticunparking", "-replayprotectionactivationtime",
	"-enableminerfund",
	// GUI args. These will be overwritten by SetupUIArgs for the GUI
	"-allowselfsignedrootcertificates", "-choosedatadir", "-lang=<lang>",
	"-min", "-resetguisettings", "-rootcertificates=<file>", "-splash",
	"-uiplatform",
	// TODO remove after the November 2020 upgrade
	"-axionactivationtime"};

	// Set all of the args and their help
	// When adding new options to the categories, please keep and ensure
	// alphabetical ordering. Do not translate _(...) -help-debug options, Many
	// technical terms, and only a very small audience, so is unnecessary stress
	// to translators.
	argsman.AddArg("-version", "Print version and exit", ArgsManager::ALLOW_ANY,
	OptionsCategory::OPTIONS);
	#if defined(HAVE_SYSTEM)
	argsman.AddArg(
	"-alertnotify=<cmd>",
	"Execute command when a relevant alert is received or we see "
	"a really long fork (%s in cmd is replaced by message)",
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	#endif
	argsman.AddArg(
	"-assumevalid=<hex>",
	strprintf(
	"If this block is in the chain assume that it and its ancestors "
	"are valid and potentially skip their script verification (0 to "
	"verify all, default: %s, testnet: %s)",
	defaultChainParams->GetConsensus().defaultAssumeValid.GetHex(),
	testnetChainParams->GetConsensus().defaultAssumeValid.GetHex()),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg("-blocksdir=<dir>",
	"Specify directory to hold blocks subdirectory for *.dat "
	"files (default: <datadir>)",
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	#if defined(HAVE_SYSTEM)
	argsman.AddArg("-blocknotify=<cmd>",
	"Execute command when the best block changes (%s in cmd is "
	"replaced by block hash)",
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	#endif
	argsman.AddArg("-blockreconstructionextratxn=<n>",
	strprintf("Extra transactions to keep in memory for compact "
	"block reconstructions (default: %u)",
	DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-blocksonly",
	strprintf("Whether to reject transactions from network peers. "
	"Automatic broadcast and rebroadcast of any transactions "
	"from inbound peers is disabled, unless the peer has the "
	"'forcerelay' permission. RPC transactions are"
	" not affected. (default: %u)",
	DEFAULT_BLOCKSONLY),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-conf=<file>",
	strprintf("Specify path to read-only configuration file. Relative "
	"paths will be prefixed by datadir location. (default: %s)",
	BITCOIN_CONF_FILENAME),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg("-datadir=<dir>", "Specify data directory",
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-dbbatchsize",
	strprintf("Maximum database write batch size in bytes (default: %u)",
	DEFAULT_DB_BATCH_SIZE),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-dbcache=<n>",
	strprintf("Set database cache size in MiB (%d to %d, default: %d)",
	MIN_DB_CACHE_MB, MAX_DB_CACHE_MB, DEFAULT_DB_CACHE_MB),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-debuglogfile=<file>",
	strprintf("Specify location of debug log file. Relative paths "
	"will be prefixed by a net-specific datadir "
	"location. (0 to disable; default: %s)",
	DEFAULT_DEBUGLOGFILE),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg("-feefilter",
	strprintf("Tell other nodes to filter invs to us by our "
	"mempool min fee (default: %d)",
	DEFAULT_FEEFILTER),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-finalizationdelay=<n>",
	strprintf("Set the minimum amount of time to wait between a "
	"block header reception and the block finalization. "
	"Unit is seconds (default: %d)",
	DEFAULT_MIN_FINALIZATION_DELAY),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-includeconf=<file>",
	"Specify additional configuration file, relative to the -datadir path "
	"(only useable from configuration file, not command line)",
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg("-maxreorgdepth=<n>",
	strprintf("Configure at what depth blocks are considered "
	"final (default: %d). Use -1 to disable.",
	DEFAULT_MAX_REORG_DEPTH),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg("-loadblock=<file>",
	"Imports blocks from external file on startup",
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg("-maxmempool=<n>",
	strprintf("Keep the transaction memory pool below <n> "
	"megabytes (default: %u)",
	DEFAULT_MAX_MEMPOOL_SIZE),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg("-maxorphantx=<n>",
	strprintf("Keep at most <n> unconnectable transactions in "
	"memory (default: %u)",
	DEFAULT_MAX_ORPHAN_TRANSACTIONS),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg("-mempoolexpiry=<n>",
	strprintf("Do not keep transactions in the mempool longer "
	"than <n> hours (default: %u)",
	DEFAULT_MEMPOOL_EXPIRY),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-minimumchainwork=<hex>",
	strprintf(
	"Minimum work assumed to exist on a valid chain in hex "
	"(default: %s, testnet: %s)",
	defaultChainParams->GetConsensus().nMinimumChainWork.GetHex(),
	testnetChainParams->GetConsensus().nMinimumChainWork.GetHex()),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-par=<n>",
	strprintf("Set the number of script verification threads (%u to %d, 0 "
	"= auto, <0 = leave that many cores free, default: %d)",
	-GetNumCores(), MAX_SCRIPTCHECK_THREADS,
	DEFAULT_SCRIPTCHECK_THREADS),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg("-persistmempool",
	strprintf("Whether to save the mempool on shutdown and load "
	"on restart (default: %u)",
	DEFAULT_PERSIST_MEMPOOL),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-pid=<file>",
	strprintf("Specify pid file. Relative paths will be prefixed "
	"by a net-specific datadir location. (default: %s)",
	BITCOIN_PID_FILENAME),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-prune=<n>",
	strprintf("Reduce storage requirements by enabling pruning (deleting) "
	"of old blocks. This allows the pruneblockchain RPC to be "
	"called to delete specific blocks, and enables automatic "
	"pruning of old blocks if a target size in MiB is provided. "
	"This mode is incompatible with -txindex and -rescan. "
	"Warning: Reverting this setting requires re-downloading the "
	"entire blockchain. (default: 0 = disable pruning blocks, 1 "
	"= allow manual pruning via RPC, >=%u = automatically prune "
	"block files to stay under the specified target size in MiB)",
	MIN_DISK_SPACE_FOR_BLOCK_FILES / 1024 / 1024),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-reindex-chainstate",
	"Rebuild chain state from the currently indexed blocks. When "
	"in pruning mode or if blocks on disk might be corrupted, use "
	"full -reindex instead.",
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-reindex",
	"Rebuild chain state and block index from the blk*.dat files on disk",
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-settings=<file>",
	strprintf(
	"Specify path to dynamic settings data file. Can be disabled with "
	"-nosettings. File is written at runtime and not meant to be "
	"edited by users (use %s instead for custom settings). Relative "
	"paths will be prefixed by datadir location. (default: %s)",
	BITCOIN_CONF_FILENAME, BITCOIN_SETTINGS_FILENAME),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	#if HAVE_SYSTEM
	argsman.AddArg("-startupnotify=<cmd>", "Execute command on startup.",
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	#endif
	#ifndef WIN32
	argsman.AddArg(
	"-sysperms",
	"Create new files with system default permissions, instead of umask "
	"077 (only effective with disabled wallet functionality)",
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	#else
	hidden_args.emplace_back("-sysperms");
	#endif
	argsman.AddArg("-txindex",
	strprintf("Maintain a full transaction index, used by the "
	"getrawtransaction rpc call (default: %d)",
	DEFAULT_TXINDEX),
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-blockfilterindex=<type>",
	strprintf("Maintain an index of compact filters by block "
	"(default: %s, values: %s).",
	DEFAULT_BLOCKFILTERINDEX, ListBlockFilterTypes()) +
	" If <type> is not supplied or if <type> = 1, indexes for "
	"all known types are enabled.",
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	argsman.AddArg(
	"-usecashaddr",
	"Use Cash Address for destination encoding instead of base58 "
	"(activate by default on Jan, 14)",
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);

	argsman.AddArg(
	"-addnode=<ip>",
	"Add a node to connect to and attempt to keep the connection "
	"open (see the `addnode` RPC command help for more info)",
	ArgsManager::ALLOW_ANY \| ArgsManager::NETWORK_ONLY,
	OptionsCategory::CONNECTION);
	argsman.AddArg("-asmap=<file>",
	strprintf("Specify asn mapping used for bucketing of the "
	"peers (default: %s). Relative paths will be "
	"prefixed by the net-specific datadir location.",
	DEFAULT_ASMAP_FILENAME),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg("-bantime=<n>",
	strprintf("Default duration (in seconds) of manually "
	"configured bans (default: %u)",
	DEFAULT_MISBEHAVING_BANTIME),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-bind=<addr>[:<port>][=onion]",
	strprintf("Bind to given address and always listen on it (default: "
	"0.0.0.0). Use [host]:port notation for IPv6. Append =onion "
	"to tag any incoming connections to that address and port as "
	"incoming Tor connections (default: 127.0.0.1:%u=onion, "
	"testnet: 127.0.0.1:%u=onion, regtest: 127.0.0.1:%u=onion)",
	defaultBaseParams->OnionServiceTargetPort(),
	testnetBaseParams->OnionServiceTargetPort(),
	regtestBaseParams->OnionServiceTargetPort()),
	ArgsManager::ALLOW_ANY \| ArgsManager::NETWORK_ONLY,
	OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-connect=<ip>",
	"Connect only to the specified node(s); -connect=0 disables automatic "
	"connections (the rules for this peer are the same as for -addnode)",
	ArgsManager::ALLOW_ANY \| ArgsManager::NETWORK_ONLY,
	OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-discover",
	"Discover own IP addresses (default: 1 when listening and no "
	"-externalip or -proxy)",
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg("-dns",
	strprintf("Allow DNS lookups for -addnode, -seednode and "
	"-connect (default: %d)",
	DEFAULT_NAME_LOOKUP),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-dnsseed",
	strprintf(
	"Query for peer addresses via DNS lookup, if low on addresses "
	"(default: %u unless -connect used)",
	DEFAULT_DNSSEED),
	ArgsManager::ALLOW_BOOL, OptionsCategory::CONNECTION);
	argsman.AddArg("-externalip=<ip>", "Specify your own public address",
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-fixedseeds",
	strprintf(
	"Allow fixed seeds if DNS seeds don't provide peers (default: %u)",
	DEFAULT_FIXEDSEEDS),
	ArgsManager::ALLOW_BOOL, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-forcednsseed",
	strprintf(
	"Always query for peer addresses via DNS lookup (default: %d)",
	DEFAULT_FORCEDNSSEED),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg("-overridednsseed",
	"If set, only use the specified DNS seed when "
	"querying for peer addresses via DNS lookup.",
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-listen",
	"Accept connections from outside (default: 1 if no -proxy or -connect)",
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-listenonion",
	strprintf("Automatically create Tor onion service (default: %d)",
	DEFAULT_LISTEN_ONION),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-maxconnections=<n>",
	strprintf("Maintain at most <n> connections to peers. The effective "
	"limit depends on system limitations and might be lower than "
	"the specified value (default: %u)",
	DEFAULT_MAX_PEER_CONNECTIONS),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg("-maxreceivebuffer=<n>",
	strprintf("Maximum per-connection receive buffer, <n>*1000 "
	"bytes (default: %u)",
	DEFAULT_MAXRECEIVEBUFFER),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-maxsendbuffer=<n>",
	strprintf(
	"Maximum per-connection send buffer, <n>*1000 bytes (default: %u)",
	DEFAULT_MAXSENDBUFFER),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-maxtimeadjustment",
	strprintf("Maximum allowed median peer time offset adjustment. Local "
	"perspective of time may be influenced by peers forward or "
	"backward by this amount. (default: %u seconds)",
	DEFAULT_MAX_TIME_ADJUSTMENT),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg("-onion=<ip:port>",
	strprintf("Use separate SOCKS5 proxy to reach peers via Tor "
	"onion services (default: %s)",
	"-proxy"),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-onlynet=<net>",
	"Make outgoing connections only through network <net> (ipv4, ipv6 or "
	"onion). Incoming connections are not affected by this option. This "
	"option can be specified multiple times to allow multiple networks.",
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg("-peerbloomfilters",
	strprintf("Support filtering of blocks and transaction with "
	"bloom filters (default: %d)",
	DEFAULT_PEERBLOOMFILTERS),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-peerblockfilters",
	strprintf(
	"Serve compact block filters to peers per BIP 157 (default: %u)",
	DEFAULT_PEERBLOCKFILTERS),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg("-permitbaremultisig",
	strprintf("Relay non-P2SH multisig (default: %d)",
	DEFAULT_PERMIT_BAREMULTISIG),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg("-port=<port>",
	strprintf("Listen for connections on <port> (default: %u, "
	"testnet: %u, regtest: %u)",
	defaultChainParams->GetDefaultPort(),
	testnetChainParams->GetDefaultPort(),
	regtestChainParams->GetDefaultPort()),
	ArgsManager::ALLOW_ANY \| ArgsManager::NETWORK_ONLY,
	OptionsCategory::CONNECTION);
	argsman.AddArg("-proxy=<ip:port>", "Connect through SOCKS5 proxy",
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-proxyrandomize",
	strprintf("Randomize credentials for every proxy connection. "
	"This enables Tor stream isolation (default: %d)",
	DEFAULT_PROXYRANDOMIZE),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-seednode=<ip>",
	"Connect to a node to retrieve peer addresses, and disconnect",
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	gArgs.AddArg("-networkactive",
	"Enable all P2P network activity (default: 1). Can be changed "
	"by the setnetworkactive RPC command",
	ArgsManager::ALLOW_BOOL, OptionsCategory::CONNECTION);
	argsman.AddArg("-timeout=<n>",
	strprintf("Specify connection timeout in milliseconds "
	"(minimum: 1, default: %d)",
	DEFAULT_CONNECT_TIMEOUT),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-peertimeout=<n>",
	strprintf("Specify p2p connection timeout in seconds. This option "
	"determines the amount of time a peer may be inactive before "
	"the connection to it is dropped. (minimum: 1, default: %d)",
	DEFAULT_PEER_CONNECT_TIMEOUT),
	true, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-torcontrol=<ip>:<port>",
	strprintf(
	"Tor control port to use if onion listening enabled (default: %s)",
	DEFAULT_TOR_CONTROL),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg("-torpassword=<pass>",
	"Tor control port password (default: empty)",
	ArgsManager::ALLOW_ANY \| ArgsManager::SENSITIVE,
	OptionsCategory::CONNECTION);
	#ifdef USE_UPNP
	#if USE_UPNP
	argsman.AddArg("-upnp",
	"Use UPnP to map the listening port (default: 1 when "
	"listening and no -proxy)",
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	#else
	argsman.AddArg(
	"-upnp",
	strprintf("Use UPnP to map the listening port (default: %u)", 0),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	#endif
	#else
	hidden_args.emplace_back("-upnp");
	#endif
	argsman.AddArg(
	"-whitebind=<[permissions@]addr>",
	"Bind to the given address and add permission flags to the peers "
	"connecting to it."
	"Use [host]:port notation for IPv6. Allowed permissions: " +
	Join(NET_PERMISSIONS_DOC, ", ") +
	". "
	"Specify multiple permissions separated by commas (default: "
	"download,noban,mempool,relay). Can be specified multiple times.",
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);

	argsman.AddArg("-whitelist=<[permissions@]IP address or network>",
	"Add permission flags to the peers connecting from the "
	"given IP address (e.g. 1.2.3.4) or CIDR-notated network "
	"(e.g. 1.2.3.0/24). "
	"Uses the same permissions as -whitebind. Can be specified "
	"multiple times.",
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
	argsman.AddArg(
	"-maxuploadtarget=<n>",
	strprintf("Tries to keep outbound traffic under the given target (in "
	"MiB per 24h). Limit does not apply to peers with 'download' "
	"permission. 0 = no limit (default: %d)",
	DEFAULT_MAX_UPLOAD_TARGET),
	ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);

	g_wallet_init_interface.AddWalletOptions(argsman);

	#if ENABLE_ZMQ
	argsman.AddArg("-zmqpubhashblock=<address>",
	"Enable publish hash block in <address>",
	ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
	argsman.AddArg("-zmqpubhashtx=<address>",
	"Enable publish hash transaction in <address>",
	ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
	argsman.AddArg("-zmqpubrawblock=<address>",
	"Enable publish raw block in <address>",
	ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
	argsman.AddArg("-zmqpubrawtx=<address>",
	"Enable publish raw transaction in <address>",
	ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
	argsman.AddArg("-zmqpubsequence=<address>",
	"Enable publish hash block and tx sequence in <address>",
	ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
	argsman.AddArg(
	"-zmqpubhashblockhwm=<n>",
	strprintf("Set publish hash block outbound message high water "
	"mark (default: %d)",
	CZMQAbstractNotifier::DEFAULT_ZMQ_SNDHWM),
	ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
	argsman.AddArg(
	"-zmqpubhashtxhwm=<n>",
	strprintf("Set publish hash transaction outbound message high "
	"water mark (default: %d)",
	CZMQAbstractNotifier::DEFAULT_ZMQ_SNDHWM),
	false, OptionsCategory::ZMQ);
	argsman.AddArg(
	"-zmqpubrawblockhwm=<n>",
	strprintf("Set publish raw block outbound message high water "
	"mark (default: %d)",
	CZMQAbstractNotifier::DEFAULT_ZMQ_SNDHWM),
	ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
	argsman.AddArg(
	"-zmqpubrawtxhwm=<n>",
	strprintf("Set publish raw transaction outbound message high "
	"water mark (default: %d)",
	CZMQAbstractNotifier::DEFAULT_ZMQ_SNDHWM),
	ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
	argsman.AddArg("-zmqpubsequencehwm=<n>",
	strprintf("Set publish hash sequence message high water mark"
	" (default: %d)",
	CZMQAbstractNotifier::DEFAULT_ZMQ_SNDHWM),
	ArgsManager::ALLOW_ANY, OptionsCategory::ZMQ);
	#else
	hidden_args.emplace_back("-zmqpubhashblock=<address>");
	hidden_args.emplace_back("-zmqpubhashtx=<address>");
	hidden_args.emplace_back("-zmqpubrawblock=<address>");
	hidden_args.emplace_back("-zmqpubrawtx=<address>");
	hidden_args.emplace_back("-zmqpubsequence=<n>");
	hidden_args.emplace_back("-zmqpubhashblockhwm=<n>");
	hidden_args.emplace_back("-zmqpubhashtxhwm=<n>");
	hidden_args.emplace_back("-zmqpubrawblockhwm=<n>");
	hidden_args.emplace_back("-zmqpubrawtxhwm=<n>");
	hidden_args.emplace_back("-zmqpubsequencehwm=<n>");
	#endif

	argsman.AddArg(
	"-checkblocks=<n>",
	strprintf("How many blocks to check at startup (default: %u, 0 = all)",
	DEFAULT_CHECKBLOCKS),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg("-checklevel=<n>",
	strprintf("How thorough the block verification of "
	"-checkblocks is: %s (0-4, default: %u)",
	Join(CHECKLEVEL_DOC, ", "), DEFAULT_CHECKLEVEL),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg("-checkblockindex",
	strprintf("Do a consistency check for the block tree, "
	"chainstate, and other validation data structures "
	"occasionally. (default: %u, regtest: %u)",
	defaultChainParams->DefaultConsistencyChecks(),
	regtestChainParams->DefaultConsistencyChecks()),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg(
	"-checkmempool=<n>",
	strprintf(
	"Run checks every <n> transactions (default: %u, regtest: %u)",
	defaultChainParams->DefaultConsistencyChecks(),
	regtestChainParams->DefaultConsistencyChecks()),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg("-checkpoints",
	strprintf("Only accept block chain matching built-in "
	"checkpoints (default: %d)",
	DEFAULT_CHECKPOINTS_ENABLED),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg("-deprecatedrpc=<method>",
	"Allows deprecated RPC method(s) to be used",
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg(
	"-stopafterblockimport",
	strprintf("Stop running after importing blocks from disk (default: %d)",
	DEFAULT_STOPAFTERBLOCKIMPORT),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg("-stopatheight",
	strprintf("Stop running after reaching the given height in "
	"the main chain (default: %u)",
	DEFAULT_STOPATHEIGHT),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg(
	"-limitancestorcount=<n>",
	strprintf("Do not accept transactions if number of in-mempool "
	"ancestors is <n> or more (default: %u)",
	DEFAULT_ANCESTOR_LIMIT),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg(
	"-limitancestorsize=<n>",
	strprintf("Do not accept transactions whose size with all in-mempool "
	"ancestors exceeds <n> kilobytes (default: %u)",
	DEFAULT_ANCESTOR_SIZE_LIMIT),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg(
	"-limitdescendantcount=<n>",
	strprintf("Do not accept transactions if any ancestor would have <n> "
	"or more in-mempool descendants (default: %u)",
	DEFAULT_DESCENDANT_LIMIT),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg(
	"-limitdescendantsize=<n>",
	strprintf("Do not accept transactions if any ancestor would have more "
	"than <n> kilobytes of in-mempool descendants (default: %u).",
	DEFAULT_DESCENDANT_SIZE_LIMIT),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg("-addrmantest", "Allows to test address relay on localhost",
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);

	argsman.AddArg("-debug=<category>",
	strprintf("Output debugging information (default: %u, "
	"supplying <category> is optional)",
	0) +
	". " +
	"If <category> is not supplied or if <category> = 1, "
	"output all debugging information. <category> can be: " +
	LogInstance().LogCategoriesString() + ".",
	ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
	argsman.AddArg(
	"-debugexclude=<category>",
	strprintf("Exclude debugging information for a category. Can be used "
	"in conjunction with -debug=1 to output debug logs for all "
	"categories except one or more specified categories."),
	ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
	argsman.AddArg(
	"-logips",
	strprintf("Include IP addresses in debug output (default: %d)",
	DEFAULT_LOGIPS),
	ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
	argsman.AddArg(
	"-logtimestamps",
	strprintf("Prepend debug output with timestamp (default: %d)",
	DEFAULT_LOGTIMESTAMPS),
	ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
	#ifdef HAVE_THREAD_LOCAL
	argsman.AddArg(
	"-logthreadnames",
	strprintf(
	"Prepend debug output with name of the originating thread (only "
	"available on platforms supporting thread_local) (default: %u)",
	DEFAULT_LOGTHREADNAMES),
	ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
	#else
	hidden_args.emplace_back("-logthreadnames");
	#endif
	argsman.AddArg(
	"-logsourcelocations",
	strprintf(
	"Prepend debug output with name of the originating source location "
	"(source file, line number and function name) (default: %u)",
	DEFAULT_LOGSOURCELOCATIONS),
	ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
	argsman.AddArg(
	"-logtimemicros",
	strprintf("Add microsecond precision to debug timestamps (default: %d)",
	DEFAULT_LOGTIMEMICROS),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg("-mocktime=<n>",
	"Replace actual time with " + UNIX_EPOCH_TIME +
	" (default: 0)",
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg(
	"-maxsigcachesize=<n>",
	strprintf("Limit size of signature cache to <n> MiB (default: %u)",
	DEFAULT_MAX_SIG_CACHE_SIZE),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg(
	"-maxscriptcachesize=<n>",
	strprintf("Limit size of script cache to <n> MiB (default: %u)",
	DEFAULT_MAX_SCRIPT_CACHE_SIZE),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg("-maxtipage=<n>",
	strprintf("Maximum tip age in seconds to consider node in "
	"initial block download (default: %u)",
	DEFAULT_MAX_TIP_AGE),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);

	argsman.AddArg(
	"-printtoconsole",
	"Send trace/debug info to console instead of debug.log file (default: "
	"1 when no -daemon. To disable logging to file, set debuglogfile=0)",
	ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
	argsman.AddArg("-printpriority",
	strprintf("Log transaction priority and fee per kB when "
	"mining blocks (default: %d)",
	DEFAULT_PRINTPRIORITY),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::DEBUG_TEST);
	argsman.AddArg(
	"-shrinkdebugfile",
	"Shrink debug.log file on client startup (default: 1 when no -debug)",
	ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);

	argsman.AddArg("-uacomment=<cmt>",
	"Append comment to the user agent string",
	ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
	argsman.AddArg("-uaclientname=<clientname>", "Set user agent client name",
	ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
	argsman.AddArg("-uaclientversion=<clientversion>",
	"Set user agent client version", ArgsManager::ALLOW_ANY,
	OptionsCategory::DEBUG_TEST);

	SetupChainParamsBaseOptions(argsman);

	argsman.AddArg(
	"-acceptnonstdtxn",
	strprintf(
	"Relay and mine \"non-standard\" transactions (%sdefault: %u)",
	"testnet/regtest only; ", defaultChainParams->RequireStandard()),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::NODE_RELAY);
	argsman.AddArg("-excessiveblocksize=<n>",
	strprintf("Do not accept blocks larger than this limit, in "
	"bytes (default: %d)",
	DEFAULT_MAX_BLOCK_SIZE),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::NODE_RELAY);
	const auto &ticker = Currency::get().ticker;
	argsman.AddArg(
	"-dustrelayfee=<amt>",
	strprintf("Fee rate (in %s/kB) used to define dust, the value of an "
	"output such that it will cost about 1/3 of its value in "
	"fees at this fee rate to spend it. (default: %s)",
	ticker, FormatMoney(DUST_RELAY_TX_FEE)),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::NODE_RELAY);

	argsman.AddArg("-bytespersigop",
	strprintf("Equivalent bytes per sigop in transactions for "
	"relay and mining (default: %u)",
	DEFAULT_BYTES_PER_SIGOP),
	ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
	argsman.AddArg(
	"-datacarrier",
	strprintf("Relay and mine data carrier transactions (default: %d)",
	DEFAULT_ACCEPT_DATACARRIER),
	ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
	argsman.AddArg(
	"-datacarriersize",
	strprintf("Maximum size of data in data carrier transactions "
	"we relay and mine (default: %u)",
	MAX_OP_RETURN_RELAY),
	ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
	argsman.AddArg(
	"-minrelaytxfee=<amt>",
	strprintf("Fees (in %s/kB) smaller than this are rejected for "
	"relaying, mining and transaction creation (default: %s)",
	ticker, FormatMoney(DEFAULT_MIN_RELAY_TX_FEE_PER_KB)),
	ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
	argsman.AddArg(
	"-whitelistrelay",
	strprintf("Add 'relay' permission to whitelisted inbound peers "
	"with default permissions. This will accept relayed "
	"transactions even when not relaying transactions "
	"(default: %d)",
	DEFAULT_WHITELISTRELAY),
	ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
	argsman.AddArg(
	"-whitelistforcerelay",
	strprintf("Add 'forcerelay' permission to whitelisted inbound peers"
	" with default permissions. This will relay transactions "
	"even if the transactions were already in the mempool "
	"(default: %d)",
	DEFAULT_WHITELISTFORCERELAY),
	ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);

	// Not sure this really belongs here, but it will do for now.
	// FIXME: This doesn't work anyways.
	argsman.AddArg("-excessutxocharge=<amt>",
	strprintf("Fees (in %s/kB) to charge per utxo created for "
	"relaying, and mining (default: %s)",
	ticker, FormatMoney(DEFAULT_UTXO_FEE)),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::NODE_RELAY);

	argsman.AddArg("-blockmaxsize=<n>",
	strprintf("Set maximum block size in bytes (default: %d)",
	DEFAULT_MAX_GENERATED_BLOCK_SIZE),
	ArgsManager::ALLOW_ANY, OptionsCategory::BLOCK_CREATION);
	argsman.AddArg(
	"-blockmintxfee=<amt>",
	strprintf("Set lowest fee rate (in %s/kB) for transactions to "
	"be included in block creation. (default: %s)",
	ticker, FormatMoney(DEFAULT_BLOCK_MIN_TX_FEE_PER_KB)),
	ArgsManager::ALLOW_ANY, OptionsCategory::BLOCK_CREATION);

	argsman.AddArg("-blockversion=<n>",
	"Override block version to test forking scenarios",
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::BLOCK_CREATION);

	argsman.AddArg("-server", "Accept command line and JSON-RPC commands",
	ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
	argsman.AddArg("-rest",
	strprintf("Accept public REST requests (default: %d)",
	DEFAULT_REST_ENABLE),
	ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
	argsman.AddArg(
	"-rpcbind=<addr>[:port]",
	"Bind to given address to listen for JSON-RPC connections. Do not "
	"expose the RPC server to untrusted networks such as the public "
	"internet! This option is ignored unless -rpcallowip is also passed. "
	"Port is optional and overrides -rpcport. Use [host]:port notation "
	"for IPv6. This option can be specified multiple times (default: "
	"127.0.0.1 and ::1 i.e., localhost)",
	ArgsManager::ALLOW_ANY \| ArgsManager::NETWORK_ONLY \|
	ArgsManager::SENSITIVE,
	OptionsCategory::RPC);
	argsman.AddArg(
	"-rpccookiefile=<loc>",
	"Location of the auth cookie. Relative paths will be prefixed "
	"by a net-specific datadir location. (default: data dir)",
	ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
	argsman.AddArg("-rpcuser=<user>", "Username for JSON-RPC connections",
	ArgsManager::ALLOW_ANY \| ArgsManager::SENSITIVE,
	OptionsCategory::RPC);
	argsman.AddArg("-rpcpassword=<pw>", "Password for JSON-RPC connections",
	ArgsManager::ALLOW_ANY \| ArgsManager::SENSITIVE,
	OptionsCategory::RPC);
	argsman.AddArg(
	"-rpcwhitelist=<whitelist>",
	"Set a whitelist to filter incoming RPC calls for a specific user. The "
	"field <whitelist> comes in the format: <USERNAME>:<rpc 1>,<rpc "
	"2>,...,<rpc n>. If multiple whitelists are set for a given user, they "
	"are set-intersected. See -rpcwhitelistdefault documentation for "
	"information on default whitelist behavior.",
	ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
	argsman.AddArg(
	"-rpcwhitelistdefault",
	"Sets default behavior for rpc whitelisting. Unless "
	"rpcwhitelistdefault is set to 0, if any -rpcwhitelist is set, the rpc "
	"server acts as if all rpc users are subject to "
	"empty-unless-otherwise-specified whitelists. If rpcwhitelistdefault "
	"is set to 1 and no -rpcwhitelist is set, rpc server acts as if all "
	"rpc users are subject to empty whitelists.",
	ArgsManager::ALLOW_BOOL, OptionsCategory::RPC);
	argsman.AddArg(
	"-rpcauth=<userpw>",
	"Username and HMAC-SHA-256 hashed password for JSON-RPC connections. "
	"The field <userpw> comes in the format: <USERNAME>:<SALT>$<HASH>. A "
	"canonical python script is included in share/rpcauth. The client then "
	"connects normally using the rpcuser=<USERNAME>/rpcpassword=<PASSWORD> "
	"pair of arguments. This option can be specified multiple times",
	ArgsManager::ALLOW_ANY \| ArgsManager::SENSITIVE, OptionsCategory::RPC);
	argsman.AddArg("-rpcport=<port>",
	strprintf("Listen for JSON-RPC connections on <port> "
	"(default: %u, testnet: %u, regtest: %u)",
	defaultBaseParams->RPCPort(),
	testnetBaseParams->RPCPort(),
	regtestBaseParams->RPCPort()),
	ArgsManager::ALLOW_ANY \| ArgsManager::NETWORK_ONLY,
	OptionsCategory::RPC);
	argsman.AddArg(
	"-rpcallowip=<ip>",
	"Allow JSON-RPC connections from specified source. Valid for "
	"<ip> are a single IP (e.g. 1.2.3.4), a network/netmask (e.g. "
	"1.2.3.4/255.255.255.0) or a network/CIDR (e.g. 1.2.3.4/24). "
	"This option can be specified multiple times",
	ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
	argsman.AddArg(
	"-rpcthreads=<n>",
	strprintf(
	"Set the number of threads to service RPC calls (default: %d)",
	DEFAULT_HTTP_THREADS),
	ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
	argsman.AddArg(
	"-rpccorsdomain=value",
	"Domain from which to accept cross origin requests (browser enforced)",
	ArgsManager::ALLOW_ANY, OptionsCategory::RPC);

	argsman.AddArg("-rpcworkqueue=<n>",
	strprintf("Set the depth of the work queue to service RPC "
	"calls (default: %d)",
	DEFAULT_HTTP_WORKQUEUE),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::RPC);
	argsman.AddArg("-rpcservertimeout=<n>",
	strprintf("Timeout during HTTP requests (default: %d)",
	DEFAULT_HTTP_SERVER_TIMEOUT),
	ArgsManager::ALLOW_ANY \| ArgsManager::DEBUG_ONLY,
	OptionsCategory::RPC);

	#if HAVE_DECL_DAEMON
	argsman.AddArg("-daemon",
	"Run in the background as a daemon and accept commands",
	ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
	#else
	hidden_args.emplace_back("-daemon");
	#endif

	// Avalanche options.
	argsman.AddArg(
	"-enableavalanche",
	strprintf("Enable avalanche (default: %u)", AVALANCHE_DEFAULT_ENABLED),
	ArgsManager::ALLOW_ANY, OptionsCategory::AVALANCHE);
	argsman.AddArg("-enableavalanchepeerdiscovery",
	strprintf("Enable avalanche peer discovery (default: %u)",
	AVALANCHE_DEFAULT_PEER_DISCOVERY_ENABLED),
	ArgsManager::ALLOW_ANY, OptionsCategory::AVALANCHE);
	argsman.AddArg(
	"-avacooldown",
	strprintf("Mandatory cooldown between two avapoll (default: %u)",
	AVALANCHE_DEFAULT_COOLDOWN),
	ArgsManager::ALLOW_ANY, OptionsCategory::AVALANCHE);
	argsman.AddArg(
	"-avadelegation",
	"Avalanche proof delegation to the master key used by this node "
	"(default: none). Should be used in conjunction with -avaproof and "
	"-avamasterkey",
	ArgsManager::ALLOW_ANY, OptionsCategory::AVALANCHE);
	argsman.AddArg("-avaproof",
	"Avalanche proof to be used by this node (default: none)",
	ArgsManager::ALLOW_ANY, OptionsCategory::AVALANCHE);
	argsman.AddArg(
	"-legacyavaproof",
	strprintf("Use the legacy avalanche proof format (default: %u)",
	AVALANCHE_DEFAULT_LEGACY_PROOF),
	ArgsManager::ALLOW_BOOL, OptionsCategory::AVALANCHE);
	argsman.AddArg("-avamasterkey",
	"Master key associated with the proof. If a proof is "
	"required, this is mandatory.",
	ArgsManager::ALLOW_ANY, OptionsCategory::AVALANCHE);
	argsman.AddArg("-avasessionkey", "Avalanche session key (default: random)",
	ArgsManager::ALLOW_ANY, OptionsCategory::AVALANCHE);

	// Add the hidden options
	argsman.AddHiddenArgs(hidden_args);
	}

	std::string LicenseInfo() {
	const std::string URL_SOURCE_CODE =
	"<https://github.com/Bitcoin-ABC/bitcoin-abc>";
	const std::string URL_WEBSITE = "<https://www.bitcoinabc.org>";

	return CopyrightHolders(strprintf(_("Copyright (C) %i-%i").translated, 2009,
	COPYRIGHT_YEAR) +
	" ") +
	"\n" + "\n" +
	strprintf(_("Please contribute if you find %s useful. "
	"Visit %s for further information about the software.")
	.translated,
	PACKAGE_NAME, URL_WEBSITE) +
	"\n" +
	strprintf(_("The source code is available from %s.").translated,
	URL_SOURCE_CODE) +
	"\n" + "\n" + _("This is experimental software.").translated + "\n" +
	strprintf(_("Distributed under the MIT software license, see the "
	"accompanying file %s or %s")
	.translated,
	"COPYING", "<https://opensource.org/licenses/MIT>") +
	"\n" + "\n" +
	strprintf(_("This product includes software developed by the "
	"OpenSSL Project for use in the OpenSSL Toolkit %s and "
	"cryptographic software written by Eric Young and UPnP "
	"software written by Thomas Bernard.")
	.translated,
	"<https://www.openssl.org>") +
	"\n";
	}

	static bool fHaveGenesis = false;
	static Mutex g_genesis_wait_mutex;
	static std::condition_variable g_genesis_wait_cv;

	static void BlockNotifyGenesisWait(const CBlockIndex *pBlockIndex) {
	if (pBlockIndex != nullptr) {
	{
	LOCK(g_genesis_wait_mutex);
	fHaveGenesis = true;
	}
	g_genesis_wait_cv.notify_all();
	}
	}

	struct CImportingNow {
	CImportingNow() {
	assert(fImporting == false);
	fImporting = true;
	}

	~CImportingNow() {
	assert(fImporting == true);
	fImporting = false;
	}
	};

	// If we're using -prune with -reindex, then delete block files that will be
	// ignored by the reindex. Since reindexing works by starting at block file 0
	// and looping until a blockfile is missing, do the same here to delete any
	// later block files after a gap. Also delete all rev files since they'll be
	// rewritten by the reindex anyway. This ensures that vinfoBlockFile is in sync
	// with what's actually on disk by the time we start downloading, so that
	// pruning works correctly.
	static void CleanupBlockRevFiles() {
	std::map<std::string, fs::path> mapBlockFiles;

	// Glob all blk?????.dat and rev?????.dat files from the blocks directory.
	// Remove the rev files immediately and insert the blk file paths into an
	// ordered map keyed by block file index.
	LogPrintf("Removing unusable blk?????.dat and rev?????.dat files for "
	"-reindex with -prune\n");
	for (const auto &file : fs::directory_iterator{gArgs.GetBlocksDirPath()}) {
	const std::string path = fs::PathToString(file.path().filename());
	if (fs::is_regular_file(file) && path.length() == 12 &&
	path.substr(8, 4) == ".dat") {
	if (path.substr(0, 3) == "blk") {
	mapBlockFiles[path.substr(3, 5)] = file.path();
	} else if (path.substr(0, 3) == "rev") {
	remove(file.path());
	}
	}
	}

	// Remove all block files that aren't part of a contiguous set starting at
	// zero by walking the ordered map (keys are block file indices) by keeping
	// a separate counter. Once we hit a gap (or if 0 doesn't exist) start
	// removing block files.
	int contiguousCounter = 0;
	for (const auto &item : mapBlockFiles) {
	if (atoi(item.first) == contiguousCounter) {
	contiguousCounter++;
	continue;
	}
	remove(item.second);
	}
	}

	#if HAVE_SYSTEM
	static void StartupNotify(const ArgsManager &args) {
	std::string cmd = args.GetArg("-startupnotify", "");
	if (!cmd.empty()) {
	std::thread t(runCommand, cmd);
	// thread runs free
	t.detach();
	}
	}
	#endif

	static void ThreadImport(const Config &config, ChainstateManager &chainman,
	std::vector<fs::path> vImportFiles,
	const ArgsManager &args) {
	ScheduleBatchPriority();

	{
	const CChainParams &chainParams = config.GetChainParams();

	CImportingNow imp;

	// -reindex
	if (fReindex) {
	int nFile = 0;
	while (true) {
	FlatFilePos pos(nFile, 0);
	if (!fs::exists(GetBlockPosFilename(pos))) {
	// No block files left to reindex
	break;
	}
	FILE *file = OpenBlockFile(pos, true);
	if (!file) {
	// This error is logged in OpenBlockFile
	break;
	}
	LogPrintf("Reindexing block file blk%05u.dat...\n",
	(unsigned int)nFile);
	LoadExternalBlockFile(config, file, &pos);
	if (ShutdownRequested()) {
	LogPrintf("Shutdown requested. Exit %s\n", __func__);
	return;
	}
	nFile++;
	}
	pblocktree->WriteReindexing(false);
	fReindex = false;
	LogPrintf("Reindexing finished\n");
	// To avoid ending up in a situation without genesis block, re-try
	// initializing (no-op if reindexing worked):
	LoadGenesisBlock(chainParams);
	}

	// -loadblock=
	for (const fs::path &path : vImportFiles) {
	FILE *file = fsbridge::fopen(path, "rb");
	if (file) {
	LogPrintf("Importing blocks file %s...\n",
	fs::PathToString(path));
	LoadExternalBlockFile(config, file);
	if (ShutdownRequested()) {
	LogPrintf("Shutdown requested. Exit %s\n", __func__);
	return;
	}
	} else {
	LogPrintf("Warning: Could not open blocks file %s\n",
	fs::PathToString(path));
	}
	}

	// Reconsider blocks we know are valid. They may have been marked
	// invalid by, for instance, running an outdated version of the node
	// software.
	const MapCheckpoints &checkpoints =
	chainParams.Checkpoints().mapCheckpoints;
	for (const MapCheckpoints::value_type &i : checkpoints) {
	const BlockHash &hash = i.second;

	LOCK(cs_main);
	CBlockIndex *pblockindex = LookupBlockIndex(hash);
	if (pblockindex && !pblockindex->nStatus.isValid()) {
	LogPrintf("Reconsidering checkpointed block %s ...\n",
	hash.GetHex());
	ResetBlockFailureFlags(pblockindex);
	}
	}

	// scan for better chains in the block chain database, that are not yet
	// connected in the active best chain

	// We can't hold cs_main during ActivateBestChain even though we're
	// accessing the chainman unique_ptrs since ABC requires us not to be
	// holding cs_main, so retrieve the relevant pointers before the ABC
	// call.
	for (CChainState *chainstate :
	WITH_LOCK(::cs_main, return chainman.GetAll())) {
	BlockValidationState state;
	if (!chainstate->ActivateBestChain(config, state, nullptr)) {
	LogPrintf("Failed to connect best block (%s)\n",
	state.ToString());
	StartShutdown();
	return;
	}
	}

	if (args.GetBoolArg("-stopafterblockimport",
	DEFAULT_STOPAFTERBLOCKIMPORT)) {
	LogPrintf("Stopping after block import\n");
	StartShutdown();
	return;
	}
	} // End scope of CImportingNow
	chainman.ActiveChainstate().LoadMempool(config, args);
	}

	/** Sanity checks
	* Ensure that Bitcoin is running in a usable environment with all
	* necessary library support.
	*/
	static bool InitSanityCheck() {
	if (!ECC_InitSanityCheck()) {
	return InitError(Untranslated(
	"Elliptic curve cryptography sanity check failure. Aborting."));
	}

	if (!glibcxx_sanity_test()) {
	return false;
	}

	if (!Random_SanityCheck()) {
	return InitError(Untranslated(
	"OS cryptographic RNG sanity check failure. Aborting."));
	}

	return true;
	}

	static bool AppInitServers(Config &config,
	HTTPRPCRequestProcessor &httpRPCRequestProcessor,
	NodeContext &node) {
	const ArgsManager &args = *Assert(node.args);
	RPCServerSignals::OnStarted(&OnRPCStarted);
	RPCServerSignals::OnStopped(&OnRPCStopped);
	if (!InitHTTPServer(config)) {
	return false;
	}

	StartRPC();
	node.rpc_interruption_point = RpcInterruptionPoint;

	if (!StartHTTPRPC(httpRPCRequestProcessor)) {
	return false;
	}
	if (args.GetBoolArg("-rest", DEFAULT_REST_ENABLE)) {
	StartREST(httpRPCRequestProcessor.context);
	}

	StartHTTPServer();
	return true;
	}

	// Parameter interaction based on rules
	void InitParameterInteraction(ArgsManager &args) {
	// when specifying an explicit binding address, you want to listen on it
	// even when -connect or -proxy is specified.
	if (args.IsArgSet("-bind")) {
	if (args.SoftSetBoolArg("-listen", true)) {
	LogPrintf(
	"%s: parameter interaction: -bind set -> setting -listen=1\n",
	__func__);
	}
	}
	if (args.IsArgSet("-whitebind")) {
	if (args.SoftSetBoolArg("-listen", true)) {
	LogPrintf("%s: parameter interaction: -whitebind set -> setting "
	"-listen=1\n",
	__func__);
	}
	}

	if (args.IsArgSet("-connect")) {
	// when only connecting to trusted nodes, do not seed via DNS, or listen
	// by default.
	if (args.SoftSetBoolArg("-dnsseed", false)) {
	LogPrintf("%s: parameter interaction: -connect set -> setting "
	"-dnsseed=0\n",
	__func__);
	}
	if (args.SoftSetBoolArg("-listen", false)) {
	LogPrintf("%s: parameter interaction: -connect set -> setting "
	"-listen=0\n",
	__func__);
	}
	}

	if (args.IsArgSet("-proxy")) {
	// to protect privacy, do not listen by default if a default proxy
	// server is specified.
	if (args.SoftSetBoolArg("-listen", false)) {
	LogPrintf(
	"%s: parameter interaction: -proxy set -> setting -listen=0\n",
	__func__);
	}
	// to protect privacy, do not use UPNP when a proxy is set. The user may
	// still specify -listen=1 to listen locally, so don't rely on this
	// happening through -listen below.
	if (args.SoftSetBoolArg("-upnp", false)) {
	LogPrintf(
	"%s: parameter interaction: -proxy set -> setting -upnp=0\n",
	__func__);
	}
	// to protect privacy, do not discover addresses by default
	if (args.SoftSetBoolArg("-discover", false)) {
	LogPrintf("%s: parameter interaction: -proxy set -> setting "
	"-discover=0\n",
	__func__);
	}
	}

	if (!args.GetBoolArg("-listen", DEFAULT_LISTEN)) {
	// do not map ports or try to retrieve public IP when not listening
	// (pointless)
	if (args.SoftSetBoolArg("-upnp", false)) {
	LogPrintf(
	"%s: parameter interaction: -listen=0 -> setting -upnp=0\n",
	__func__);
	}
	if (args.SoftSetBoolArg("-discover", false)) {
	LogPrintf(
	"%s: parameter interaction: -listen=0 -> setting -discover=0\n",
	__func__);
	}
	if (args.SoftSetBoolArg("-listenonion", false)) {
	LogPrintf("%s: parameter interaction: -listen=0 -> setting "
	"-listenonion=0\n",
	__func__);
	}
	}

	if (args.IsArgSet("-externalip")) {
	// if an explicit public IP is specified, do not try to find others
	if (args.SoftSetBoolArg("-discover", false)) {
	LogPrintf("%s: parameter interaction: -externalip set -> setting "
	"-discover=0\n",
	__func__);
	}
	}

	// disable whitelistrelay in blocksonly mode
	if (args.GetBoolArg("-blocksonly", DEFAULT_BLOCKSONLY)) {
	if (args.SoftSetBoolArg("-whitelistrelay", false)) {
	LogPrintf("%s: parameter interaction: -blocksonly=1 -> setting "
	"-whitelistrelay=0\n",
	__func__);
	}
	}

	// Forcing relay from whitelisted hosts implies we will accept relays from
	// them in the first place.
	if (args.GetBoolArg("-whitelistforcerelay", DEFAULT_WHITELISTFORCERELAY)) {
	if (args.SoftSetBoolArg("-whitelistrelay", true)) {
	LogPrintf("%s: parameter interaction: -whitelistforcerelay=1 -> "
	"setting -whitelistrelay=1\n",
	__func__);
	}
	}
	}

	/**
	* Initialize global loggers.
	*
	* Note that this is called very early in the process lifetime, so you should be
	* careful about what global state you rely on here.
	*/
	void InitLogging(const ArgsManager &args) {
	LogInstance().m_print_to_file = !args.IsArgNegated("-debuglogfile");
	LogInstance().m_file_path = AbsPathForConfigVal(
	fs::PathFromString(args.GetArg("-debuglogfile", DEFAULT_DEBUGLOGFILE)));

	LogInstance().m_print_to_console =
	args.GetBoolArg("-printtoconsole", !args.GetBoolArg("-daemon", false));
	LogInstance().m_log_timestamps =
	args.GetBoolArg("-logtimestamps", DEFAULT_LOGTIMESTAMPS);
	LogInstance().m_log_time_micros =
	args.GetBoolArg("-logtimemicros", DEFAULT_LOGTIMEMICROS);
	#ifdef HAVE_THREAD_LOCAL
	LogInstance().m_log_threadnames =
	args.GetBoolArg("-logthreadnames", DEFAULT_LOGTHREADNAMES);
	#endif
	LogInstance().m_log_sourcelocations =
	args.GetBoolArg("-logsourcelocations", DEFAULT_LOGSOURCELOCATIONS);

	fLogIPs = args.GetBoolArg("-logips", DEFAULT_LOGIPS);

	std::string version_string = FormatFullVersion();
	#ifdef DEBUG
	version_string += " (debug build)";
	#else
	version_string += " (release build)";
	#endif
	LogPrintf("%s version %s\n", CLIENT_NAME, version_string);
	}

	namespace { // Variables internal to initialization process only

	int nMaxConnections;
	int nUserMaxConnections;
	int nFD;
	ServiceFlags nLocalServices = ServiceFlags(NODE_NETWORK \| NODE_NETWORK_LIMITED);
	int64_t peer_connect_timeout;
	std::set<BlockFilterType> g_enabled_filter_types;

	} // namespace

	[[noreturn]] static void new_handler_terminate() {
	// Rather than throwing std::bad-alloc if allocation fails, terminate
	// immediately to (try to) avoid chain corruption. Since LogPrintf may
	// itself allocate memory, set the handler directly to terminate first.
	std::set_new_handler(std::terminate);
	LogPrintf("Error: Out of memory. Terminating.\n");

	// The log was successful, terminate now.
	std::terminate();
	};

	bool AppInitBasicSetup(ArgsManager &args) {
	// Step 1: setup
	#ifdef _MSC_VER
	// Turn off Microsoft heap dump noise
	_CrtSetReportMode(_CRT_WARN, _CRTDBG_MODE_FILE);
	_CrtSetReportFile(_CRT_WARN, CreateFileA("NUL", GENERIC_WRITE, 0, nullptr,
	OPEN_EXISTING, 0, 0));
	// Disable confusing "helpful" text message on abort, Ctrl-C
	_set_abort_behavior(0, _WRITE_ABORT_MSG \| _CALL_REPORTFAULT);
	#endif
	#ifdef WIN32
	// Enable Data Execution Prevention (DEP)
	SetProcessDEPPolicy(PROCESS_DEP_ENABLE);
	#endif

	if (!SetupNetworking()) {
	return InitError(Untranslated("Initializing networking failed"));
	}

	#ifndef WIN32
	if (!args.GetBoolArg("-sysperms", false)) {
	umask(077);
	}

	// Clean shutdown on SIGTERM
	registerSignalHandler(SIGTERM, HandleSIGTERM);
	registerSignalHandler(SIGINT, HandleSIGTERM);

	// Reopen debug.log on SIGHUP
	registerSignalHandler(SIGHUP, HandleSIGHUP);

	// Ignore SIGPIPE, otherwise it will bring the daemon down if the client
	// closes unexpectedly
	signal(SIGPIPE, SIG_IGN);
	#else
	SetConsoleCtrlHandler(consoleCtrlHandler, true);
	#endif

	std::set_new_handler(new_handler_terminate);

	return true;
	}

	bool AppInitParameterInteraction(Config &config, const ArgsManager &args) {
	const CChainParams &chainparams = config.GetChainParams();
	// Step 2: parameter interactions

	// also see: InitParameterInteraction()

	// Error if network-specific options (-addnode, -connect, etc) are
	// specified in default section of config file, but not overridden
	// on the command line or in this network's section of the config file.
	std::string network = args.GetChainName();
	bilingual_str errors;
	for (const auto &arg : args.GetUnsuitableSectionOnlyArgs()) {
	errors += strprintf(_("Config setting for %s only applied on %s "
	"network when in [%s] section.") +
	Untranslated("\n"),
	arg, network, network);
	}

	if (!errors.empty()) {
	return InitError(errors);
	}

	// Warn if unrecognized section name are present in the config file.
	bilingual_str warnings;
	for (const auto &section : args.GetUnrecognizedSections()) {
	warnings += strprintf(Untranslated("%s:%i ") +
	_("Section [%s] is not recognized.") +
	Untranslated("\n"),
	section.m_file, section.m_line, section.m_name);
	}

	if (!warnings.empty()) {
	InitWarning(warnings);
	}

	if (!fs::is_directory(gArgs.GetBlocksDirPath())) {
	return InitError(
	strprintf(_("Specified blocks directory \"%s\" does not exist."),
	args.GetArg("-blocksdir", "")));
	}

	// parse and validate enabled filter types
	std::string blockfilterindex_value =
	args.GetArg("-blockfilterindex", DEFAULT_BLOCKFILTERINDEX);
	if (blockfilterindex_value == "" \|\| blockfilterindex_value == "1") {
	g_enabled_filter_types = AllBlockFilterTypes();
	} else if (blockfilterindex_value != "0") {
	const std::vector<std::string> names =
	args.GetArgs("-blockfilterindex");
	for (const auto &name : names) {
	BlockFilterType filter_type;
	if (!BlockFilterTypeByName(name, filter_type)) {
	return InitError(
	strprintf(_("Unknown -blockfilterindex value %s."), name));
	}
	g_enabled_filter_types.insert(filter_type);
	}
	}

	// Signal NODE_COMPACT_FILTERS if peerblockfilters and basic filters index
	// are both enabled.
	if (gArgs.GetBoolArg("-peerblockfilters", DEFAULT_PEERBLOCKFILTERS)) {
	if (g_enabled_filter_types.count(BlockFilterType::BASIC) != 1) {
	return InitError(
	_("Cannot set -peerblockfilters without -blockfilterindex."));
	}

	nLocalServices = ServiceFlags(nLocalServices \| NODE_COMPACT_FILTERS);
	}

	// if using block pruning, then disallow txindex
	if (args.GetArg("-prune", 0)) {
	if (args.GetBoolArg("-txindex", DEFAULT_TXINDEX)) {
	return InitError(_("Prune mode is incompatible with -txindex."));
	}
	if (!g_enabled_filter_types.empty()) {
	return InitError(
	_("Prune mode is incompatible with -blockfilterindex."));
	}
	}

	// -bind and -whitebind can't be set when not listening
	size_t nUserBind =
	args.GetArgs("-bind").size() + args.GetArgs("-whitebind").size();
	if (nUserBind != 0 && !args.GetBoolArg("-listen", DEFAULT_LISTEN)) {
	return InitError(Untranslated(
	"Cannot set -bind or -whitebind together with -listen=0"));
	}

	// Make sure enough file descriptors are available
	int nBind = std::max(nUserBind, size_t(1));
	nUserMaxConnections =
	args.GetArg("-maxconnections", DEFAULT_MAX_PEER_CONNECTIONS);
	nMaxConnections = std::max(nUserMaxConnections, 0);

	// Trim requested connection counts, to fit into system limitations
	// <int> in std::min<int>(...) to work around FreeBSD compilation issue
	// described in #2695
	nFD = RaiseFileDescriptorLimit(nMaxConnections + nBind +
	MIN_CORE_FILEDESCRIPTORS +
	MAX_ADDNODE_CONNECTIONS);
	#ifdef USE_POLL
	int fd_max = nFD;
	#else
	int fd_max = FD_SETSIZE;
	#endif
	nMaxConnections =
	std::max(std::min<int>(nMaxConnections, fd_max - nBind -
	MIN_CORE_FILEDESCRIPTORS -
	MAX_ADDNODE_CONNECTIONS),
	0);
	if (nFD < MIN_CORE_FILEDESCRIPTORS) {
	return InitError(_("Not enough file descriptors available."));
	}
	nMaxConnections =
	std::min(nFD - MIN_CORE_FILEDESCRIPTORS - MAX_ADDNODE_CONNECTIONS,
	nMaxConnections);

	if (nMaxConnections < nUserMaxConnections) {
	// Not categorizing as "Warning" because this is the normal behavior for
	// platforms using the select() interface for which FD_SETSIZE is
	// usually 1024.
	LogPrintf("Reducing -maxconnections from %d to %d, because of system "
	"limitations.\n",
	nUserMaxConnections, nMaxConnections);
	}

	// Step 3: parameter-to-internal-flags
	if (args.IsArgSet("-debug")) {
	// Special-case: if -debug=0/-nodebug is set, turn off debugging
	// messages
	const std::vector<std::string> &categories = args.GetArgs("-debug");
	if (std::none_of(
	categories.begin(), categories.end(),
	[](std::string cat) { return cat == "0" \|\| cat == "none"; })) {
	for (const auto &cat : categories) {
	if (!LogInstance().EnableCategory(cat)) {
	InitWarning(
	strprintf(_("Unsupported logging category %s=%s."),
	"-debug", cat));
	}
	}
	}
	}

	// Now remove the logging categories which were explicitly excluded
	for (const std::string &cat : args.GetArgs("-debugexclude")) {
	if (!LogInstance().DisableCategory(cat)) {
	InitWarning(strprintf(_("Unsupported logging category %s=%s."),
	"-debugexclude", cat));
	}
	}

	fCheckBlockIndex = args.GetBoolArg("-checkblockindex",
	chainparams.DefaultConsistencyChecks());
	fCheckpointsEnabled =
	args.GetBoolArg("-checkpoints", DEFAULT_CHECKPOINTS_ENABLED);
	if (fCheckpointsEnabled) {
	LogPrintf("Checkpoints will be verified.\n");
	} else {
	LogPrintf("Skipping checkpoint verification.\n");
	}

	hashAssumeValid = BlockHash::fromHex(
	args.GetArg("-assumevalid",
	chainparams.GetConsensus().defaultAssumeValid.GetHex()));
	if (!hashAssumeValid.IsNull()) {
	LogPrintf("Assuming ancestors of block %s have valid signatures.\n",
	hashAssumeValid.GetHex());
	} else {
	LogPrintf("Validating signatures for all blocks.\n");
	}

	if (args.IsArgSet("-minimumchainwork")) {
	const std::string minChainWorkStr =
	args.GetArg("-minimumchainwork", "");
	if (!IsHexNumber(minChainWorkStr)) {
	return InitError(strprintf(
	Untranslated(
	"Invalid non-hex (%s) minimum chain work value specified"),
	minChainWorkStr));
	}
	nMinimumChainWork = UintToArith256(uint256S(minChainWorkStr));
	} else {
	nMinimumChainWork =
	UintToArith256(chainparams.GetConsensus().nMinimumChainWork);
	}
	LogPrintf("Setting nMinimumChainWork=%s\n", nMinimumChainWork.GetHex());
	if (nMinimumChainWork <
	UintToArith256(chainparams.GetConsensus().nMinimumChainWork)) {
	LogPrintf("Warning: nMinimumChainWork set below default value of %s\n",
	chainparams.GetConsensus().nMinimumChainWork.GetHex());
	}

	// mempool limits
	int64_t nMempoolSizeMax =
	args.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000;
	int64_t nMempoolSizeMin =
	args.GetArg("-limitdescendantsize", DEFAULT_DESCENDANT_SIZE_LIMIT) *
	1000 * 40;
	if (nMempoolSizeMax < 0 \|\| nMempoolSizeMax < nMempoolSizeMin) {
	return InitError(strprintf(_("-maxmempool must be at least %d MB"),
	std::ceil(nMempoolSizeMin / 1000000.0)));
	}

	// Configure excessive block size.
	const int64_t nProposedExcessiveBlockSize =
	args.GetArg("-excessiveblocksize", DEFAULT_MAX_BLOCK_SIZE);
	if (nProposedExcessiveBlockSize <= 0 \|\|
	!config.SetMaxBlockSize(nProposedExcessiveBlockSize)) {
	return InitError(
	_("Excessive block size must be > 1,000,000 bytes (1MB)"));
	}

	// Check blockmaxsize does not exceed maximum accepted block size.
	const int64_t nProposedMaxGeneratedBlockSize =
	args.GetArg("-blockmaxsize", DEFAULT_MAX_GENERATED_BLOCK_SIZE);
	if (nProposedMaxGeneratedBlockSize <= 0) {
	return InitError(_("Max generated block size must be greater than 0"));
	}
	if (uint64_t(nProposedMaxGeneratedBlockSize) > config.GetMaxBlockSize()) {
	return InitError(_("Max generated block size (blockmaxsize) cannot "
	"exceed the excessive block size "
	"(excessiveblocksize)"));
	}

	// block pruning; get the amount of disk space (in MiB) to allot for block &
	// undo files
	int64_t nPruneArg = args.GetArg("-prune", 0);
	if (nPruneArg < 0) {
	return InitError(
	_("Prune cannot be configured with a negative value."));
	}
	nPruneTarget = (uint64_t)nPruneArg * 1024 * 1024;
	if (nPruneArg == 1) {
	// manual pruning: -prune=1
	LogPrintf("Block pruning enabled. Use RPC call "
	"pruneblockchain(height) to manually prune block and undo "
	"files.\n");
	nPruneTarget = std::numeric_limits<uint64_t>::max();
	fPruneMode = true;
	} else if (nPruneTarget) {
	if (nPruneTarget < MIN_DISK_SPACE_FOR_BLOCK_FILES) {
	return InitError(
	strprintf(_("Prune configured below the minimum of %d MiB. "
	"Please use a higher number."),
	MIN_DISK_SPACE_FOR_BLOCK_FILES / 1024 / 1024));
	}
	LogPrintf("Prune configured to target %u MiB on disk for block and "
	"undo files.\n",
	nPruneTarget / 1024 / 1024);
	fPruneMode = true;
	}

	nConnectTimeout = args.GetArg("-timeout", DEFAULT_CONNECT_TIMEOUT);
	if (nConnectTimeout <= 0) {
	nConnectTimeout = DEFAULT_CONNECT_TIMEOUT;
	}

	peer_connect_timeout =
	args.GetArg("-peertimeout", DEFAULT_PEER_CONNECT_TIMEOUT);
	if (peer_connect_timeout <= 0) {
	return InitError(Untranslated(
	"peertimeout cannot be configured with a negative value."));
	}

	// Obtain the amount to charge excess UTXO
	if (args.IsArgSet("-excessutxocharge")) {
	Amount n = Amount::zero();
	auto parsed = ParseMoney(args.GetArg("-excessutxocharge", ""), n);
	if (!parsed \|\| Amount::zero() > n) {
	return InitError(AmountErrMsg(
	"excessutxocharge", args.GetArg("-excessutxocharge", "")));
	}
	config.SetExcessUTXOCharge(n);
	} else {
	config.SetExcessUTXOCharge(DEFAULT_UTXO_FEE);
	}

	if (args.IsArgSet("-minrelaytxfee")) {
	Amount n = Amount::zero();
	auto parsed = ParseMoney(args.GetArg("-minrelaytxfee", ""), n);
	if (!parsed \|\| n == Amount::zero()) {
	return InitError(AmountErrMsg("minrelaytxfee",
	args.GetArg("-minrelaytxfee", "")));
	}
	// High fee check is done afterward in CWallet::Create()
	::minRelayTxFee = CFeeRate(n);
	}

	// Sanity check argument for min fee for including tx in block
	// TODO: Harmonize which arguments need sanity checking and where that
	// happens.
	if (args.IsArgSet("-blockmintxfee")) {
	Amount n = Amount::zero();
	if (!ParseMoney(args.GetArg("-blockmintxfee", ""), n)) {
	return InitError(AmountErrMsg("blockmintxfee",
	args.GetArg("-blockmintxfee", "")));
	}
	}

	// Feerate used to define dust. Shouldn't be changed lightly as old
	// implementations may inadvertently create non-standard transactions.
	if (args.IsArgSet("-dustrelayfee")) {
	Amount n = Amount::zero();
	auto parsed = ParseMoney(args.GetArg("-dustrelayfee", ""), n);
	if (!parsed \|\| Amount::zero() == n) {
	return InitError(
	AmountErrMsg("dustrelayfee", args.GetArg("-dustrelayfee", "")));
	}
	dustRelayFee = CFeeRate(n);
	}

	fRequireStandard =
	!args.GetBoolArg("-acceptnonstdtxn", !chainparams.RequireStandard());
	if (!chainparams.IsTestChain() && !fRequireStandard) {
	return InitError(strprintf(
	Untranslated(
	"acceptnonstdtxn is not currently supported for %s chain"),
	chainparams.NetworkIDString()));
	}
	nBytesPerSigOp = args.GetArg("-bytespersigop", nBytesPerSigOp);

	if (!g_wallet_init_interface.ParameterInteraction()) {
	return false;
	}

	fIsBareMultisigStd =
	args.GetBoolArg("-permitbaremultisig", DEFAULT_PERMIT_BAREMULTISIG);
	fAcceptDatacarrier =
	args.GetBoolArg("-datacarrier", DEFAULT_ACCEPT_DATACARRIER);

	// Option to startup with mocktime set (used for regression testing):
	SetMockTime(args.GetArg("-mocktime", 0)); // SetMockTime(0) is a no-op

	if (args.GetBoolArg("-peerbloomfilters", DEFAULT_PEERBLOOMFILTERS)) {
	nLocalServices = ServiceFlags(nLocalServices \| NODE_BLOOM);
	}

	nMaxTipAge = args.GetArg("-maxtipage", DEFAULT_MAX_TIP_AGE);

	if (args.IsArgSet("-proxy") && args.GetArg("-proxy", "").empty()) {
	return InitError(_(
	"No proxy server specified. Use -proxy=<ip> or -proxy=<ip:port>."));
	}

	return true;
	}

	static bool LockDataDirectory(bool probeOnly) {
	// Make sure only a single Bitcoin process is using the data directory.
	fs::path datadir = GetDataDir();
	if (!DirIsWritable(datadir)) {
	return InitError(strprintf(
	_("Cannot write to data directory '%s'; check permissions."),
	fs::PathToString(datadir)));
	}
	if (!LockDirectory(datadir, ".lock", probeOnly)) {
	return InitError(strprintf(_("Cannot obtain a lock on data directory "
	"%s. %s is probably already running."),
	fs::PathToString(datadir), PACKAGE_NAME));
	}
	return true;
	}

	bool AppInitSanityChecks() {
	// Step 4: sanity checks

	// Initialize elliptic curve code
	std::string sha256_algo = SHA256AutoDetect();
	LogPrintf("Using the '%s' SHA256 implementation\n", sha256_algo);
	RandomInit();
	ECC_Start();
	globalVerifyHandle.reset(new ECCVerifyHandle());

	// Sanity check
	if (!InitSanityCheck()) {
	return InitError(strprintf(
	_("Initialization sanity check failed. %s is shutting down."),
	PACKAGE_NAME));
	}

	// Probe the data directory lock to give an early error message, if possible
	// We cannot hold the data directory lock here, as the forking for daemon()
	// hasn't yet happened, and a fork will cause weird behavior to it.
	return LockDataDirectory(true);
	}

	bool AppInitLockDataDirectory() {
	// After daemonization get the data directory lock again and hold on to it
	// until exit. This creates a slight window for a race condition to happen,
	// however this condition is harmless: it will at most make us exit without
	// printing a message to console.
	if (!LockDataDirectory(false)) {
	// Detailed error printed inside LockDataDirectory
	return false;
	}
	return true;
	}

	bool AppInitInterfaces(NodeContext &node) {
	node.chain = interfaces::MakeChain(node, Params());
	// Create client interfaces for wallets that are supposed to be loaded
	// according to -wallet and -disablewallet options. This only constructs
	// the interfaces, it doesn't load wallet data. Wallets actually get loaded
	// when load() and start() interface methods are called below.
	g_wallet_init_interface.Construct(node);
	return true;
	}

	bool AppInitMain(Config &config, RPCServer &rpcServer,
	HTTPRPCRequestProcessor &httpRPCRequestProcessor,
	NodeContext &node,
	interfaces::BlockAndHeaderTipInfo *tip_info) {
	// Step 4a: application initialization
	const ArgsManager &args = *Assert(node.args);
	const CChainParams &chainparams = config.GetChainParams();

	if (!CreatePidFile(args)) {
	// Detailed error printed inside CreatePidFile().
	return false;
	}

	BCLog::Logger &logger = LogInstance();
	if (logger.m_print_to_file) {
	if (args.GetBoolArg("-shrinkdebugfile",
	logger.DefaultShrinkDebugFile())) {
	// Do this first since it both loads a bunch of debug.log into
	// memory, and because this needs to happen before any other
	// debug.log printing.
	logger.ShrinkDebugFile();
	}
	}

	if (!logger.StartLogging()) {
	return InitError(
	strprintf(Untranslated("Could not open debug log file %s"),
	fs::PathToString(logger.m_file_path)));
	}

	if (!logger.m_log_timestamps) {
	LogPrintf("Startup time: %s\n", FormatISO8601DateTime(GetTime()));
	}
	LogPrintf("Default data directory %s\n",
	fs::PathToString(GetDefaultDataDir()));
	LogPrintf("Using data directory %s\n", fs::PathToString(GetDataDir()));

	// Only log conf file usage message if conf file actually exists.
	fs::path config_file_path =
	GetConfigFile(args.GetArg("-conf", BITCOIN_CONF_FILENAME));
	if (fs::exists(config_file_path)) {
	LogPrintf("Config file: %s\n", fs::PathToString(config_file_path));
	} else if (args.IsArgSet("-conf")) {
	// Warn if no conf file exists at path provided by user
	InitWarning(
	strprintf(_("The specified config file %s does not exist\n"),
	fs::PathToString(config_file_path)));
	} else {
	// Not categorizing as "Warning" because it's the default behavior
	LogPrintf("Config file: %s (not found, skipping)\n",
	fs::PathToString(config_file_path));
	}

	// Log the config arguments to debug.log
	args.LogArgs();

	LogPrintf("Using at most %i automatic connections (%i file descriptors "
	"available)\n",
	nMaxConnections, nFD);

	// Warn about relative -datadir path.
	if (args.IsArgSet("-datadir") &&
	!fs::PathFromString(args.GetArg("-datadir", "")).is_absolute()) {
	LogPrintf("Warning: relative datadir option '%s' specified, which will "
	"be interpreted relative to the current working directory "
	"'%s'. This is fragile, because if bitcoin is started in the "
	"future from a different location, it will be unable to "
	"locate the current data files. There could also be data "
	"loss if bitcoin is started while in a temporary "
	"directory.\n",
	args.GetArg("-datadir", ""),
	fs::PathToString(fs::current_path()));
	}

	InitSignatureCache();
	InitScriptExecutionCache();

	int script_threads = args.GetArg("-par", DEFAULT_SCRIPTCHECK_THREADS);
	if (script_threads <= 0) {
	// -par=0 means autodetect (number of cores - 1 script threads)
	// -par=-n means "leave n cores free" (number of cores - n - 1 script
	// threads)
	script_threads += GetNumCores();
	}

	// Subtract 1 because the main thread counts towards the par threads
	script_threads = std::max(script_threads - 1, 0);

	// Number of script-checking threads <= MAX_SCRIPTCHECK_THREADS
	script_threads = std::min(script_threads, MAX_SCRIPTCHECK_THREADS);

	LogPrintf("Script verification uses %d additional threads\n",
	script_threads);
	if (script_threads >= 1) {
	- for (int i = 0; i < script_threads; ++i) {
	- threadGroup.create_thread([i]() { return ThreadScriptCheck(i); });
	- }
	+ StartScriptCheckWorkerThreads(script_threads);
	}

	assert(!node.scheduler);
	node.scheduler = std::make_unique<CScheduler>();

	// Start the lightweight task scheduler thread
	CScheduler::Function serviceLoop = [&node] {
	node.scheduler->serviceQueue();
	};
	threadGroup.create_thread(std::bind(&TraceThread<CScheduler::Function>,
	"scheduler", serviceLoop));

	// Gather some entropy once per minute.
	node.scheduler->scheduleEvery(
	[] {
	RandAddPeriodic();
	return true;
	},
	std::chrono::minutes{1});

	GetMainSignals().RegisterBackgroundSignalScheduler(*node.scheduler);

	/**
	* Register RPC commands regardless of -server setting so they will be
	* available in the GUI RPC console even if external calls are disabled.
	*/
	RegisterAllRPCCommands(config, rpcServer, tableRPC);
	for (const auto &client : node.chain_clients) {
	client->registerRpcs();
	}
	#if ENABLE_ZMQ
	RegisterZMQRPCCommands(tableRPC);
	#endif

	/**
	* Start the RPC server. It will be started in "warmup" mode and not
	* process calls yet (but it will verify that the server is there and will
	* be ready later). Warmup mode will be completed when initialisation is
	* finished.
	*/
	if (args.GetBoolArg("-server", false)) {
	uiInterface.InitMessage_connect(SetRPCWarmupStatus);
	if (!AppInitServers(config, httpRPCRequestProcessor, node)) {
	return InitError(
	_("Unable to start HTTP server. See debug log for details."));
	}
	}

	// Step 5: verify wallet database integrity
	for (const auto &client : node.chain_clients) {
	if (!client->verify()) {
	return false;
	}
	}

	// Step 6: network initialization

	// Note that we absolutely cannot open any actual connections
	// until the very end ("start node") as the UTXO/block state
	// is not yet setup and may end up being set up twice if we
	// need to reindex later.

	assert(!node.banman);
	node.banman = std::make_unique<BanMan>(
	GetDataDir() / "banlist.dat", config.GetChainParams(), &uiInterface,
	args.GetArg("-bantime", DEFAULT_MISBEHAVING_BANTIME));
	assert(!node.connman);
	node.connman = std::make_unique<CConnman>(
	config, GetRand(std::numeric_limits<uint64_t>::max()),
	GetRand(std::numeric_limits<uint64_t>::max()),
	gArgs.GetBoolArg("-networkactive", true));

	assert(!node.mempool);
	int check_ratio = std::min<int>(
	std::max<int>(
	args.GetArg("-checkmempool",
	chainparams.DefaultConsistencyChecks() ? 1 : 0),
	0),
	1000000);
	node.mempool = std::make_unique<CTxMemPool>(check_ratio);

	assert(!node.chainman);
	node.chainman = &g_chainman;
	ChainstateManager &chainman = *Assert(node.chainman);

	assert(!node.peerman);
	node.peerman =
	PeerManager::make(chainparams, *node.connman, node.banman.get(),
	node.scheduler, chainman, node.mempool,
	args.GetBoolArg("-blocksonly", DEFAULT_BLOCKSONLY));
	RegisterValidationInterface(node.peerman.get());

	// sanitize comments per BIP-0014, format user agent and check total size
	std::vector<std::string> uacomments;
	for (const std::string &cmt : args.GetArgs("-uacomment")) {
	if (cmt != SanitizeString(cmt, SAFE_CHARS_UA_COMMENT)) {
	return InitError(strprintf(
	_("User Agent comment (%s) contains unsafe characters."), cmt));
	}
	uacomments.push_back(cmt);
	}
	const std::string client_name = args.GetArg("-uaclientname", CLIENT_NAME);
	const std::string client_version =
	args.GetArg("-uaclientversion", FormatVersion(CLIENT_VERSION));
	if (client_name != SanitizeString(client_name, SAFE_CHARS_UA_COMMENT)) {
	return InitError(strprintf(
	_("-uaclientname (%s) contains invalid characters."), client_name));
	}
	if (client_version !=
	SanitizeString(client_version, SAFE_CHARS_UA_COMMENT)) {
	return InitError(
	strprintf(_("-uaclientversion (%s) contains invalid characters."),
	client_version));
	}
	const std::string strSubVersion =
	FormatUserAgent(client_name, client_version, uacomments);
	if (strSubVersion.size() > MAX_SUBVERSION_LENGTH) {
	return InitError(strprintf(
	_("Total length of network version string (%i) exceeds maximum "
	"length (%i). Reduce the number or size of uacomments."),
	strSubVersion.size(), MAX_SUBVERSION_LENGTH));
	}

	if (args.IsArgSet("-onlynet")) {
	std::set<enum Network> nets;
	for (const std::string &snet : args.GetArgs("-onlynet")) {
	enum Network net = ParseNetwork(snet);
	if (net == NET_UNROUTABLE) {
	return InitError(strprintf(
	_("Unknown network specified in -onlynet: '%s'"), snet));
	}
	nets.insert(net);
	}
	for (int n = 0; n < NET_MAX; n++) {
	enum Network net = (enum Network)n;
	if (!nets.count(net)) {
	SetReachable(net, false);
	}
	}
	}

	// Check for host lookup allowed before parsing any network related
	// parameters
	fNameLookup = args.GetBoolArg("-dns", DEFAULT_NAME_LOOKUP);

	bool proxyRandomize =
	args.GetBoolArg("-proxyrandomize", DEFAULT_PROXYRANDOMIZE);
	// -proxy sets a proxy for all outgoing network traffic
	// -noproxy (or -proxy=0) as well as the empty string can be used to not set
	// a proxy, this is the default
	std::string proxyArg = args.GetArg("-proxy", "");
	SetReachable(NET_ONION, false);
	if (proxyArg != "" && proxyArg != "0") {
	CService proxyAddr;
	if (!Lookup(proxyArg, proxyAddr, 9050, fNameLookup)) {
	return InitError(strprintf(
	_("Invalid -proxy address or hostname: '%s'"), proxyArg));
	}

	proxyType addrProxy = proxyType(proxyAddr, proxyRandomize);
	if (!addrProxy.IsValid()) {
	return InitError(strprintf(
	_("Invalid -proxy address or hostname: '%s'"), proxyArg));
	}

	SetProxy(NET_IPV4, addrProxy);
	SetProxy(NET_IPV6, addrProxy);
	SetProxy(NET_ONION, addrProxy);
	SetNameProxy(addrProxy);
	// by default, -proxy sets onion as reachable, unless -noonion later
	SetReachable(NET_ONION, true);
	}

	// -onion can be used to set only a proxy for .onion, or override normal
	// proxy for .onion addresses.
	// -noonion (or -onion=0) disables connecting to .onion entirely. An empty
	// string is used to not override the onion proxy (in which case it defaults
	// to -proxy set above, or none)
	std::string onionArg = args.GetArg("-onion", "");
	if (onionArg != "") {
	if (onionArg == "0") {
	// Handle -noonion/-onion=0
	SetReachable(NET_ONION, false);
	} else {
	CService onionProxy;
	if (!Lookup(onionArg, onionProxy, 9050, fNameLookup)) {
	return InitError(strprintf(
	_("Invalid -onion address or hostname: '%s'"), onionArg));
	}
	proxyType addrOnion = proxyType(onionProxy, proxyRandomize);
	if (!addrOnion.IsValid()) {
	return InitError(strprintf(
	_("Invalid -onion address or hostname: '%s'"), onionArg));
	}
	SetProxy(NET_ONION, addrOnion);
	SetReachable(NET_ONION, true);
	}
	}

	fListen = args.GetBoolArg("-listen", DEFAULT_LISTEN);
	fDiscover = args.GetBoolArg("-discover", true);

	for (const std::string &strAddr : args.GetArgs("-externalip")) {
	CService addrLocal;
	if (Lookup(strAddr, addrLocal, GetListenPort(), fNameLookup) &&
	addrLocal.IsValid()) {
	AddLocal(addrLocal, LOCAL_MANUAL);
	} else {
	return InitError(ResolveErrMsg("externalip", strAddr));
	}
	}

	// Read asmap file if configured
	if (args.IsArgSet("-asmap")) {
	fs::path asmap_path = fs::PathFromString(args.GetArg("-asmap", ""));
	if (asmap_path.empty()) {
	asmap_path = fs::PathFromString(DEFAULT_ASMAP_FILENAME);
	}
	if (!asmap_path.is_absolute()) {
	asmap_path = GetDataDir() / asmap_path;
	}
	if (!fs::exists(asmap_path)) {
	InitError(strprintf(_("Could not find asmap file %s"),
	fs::quoted(fs::PathToString(asmap_path))));
	return false;
	}
	std::vector<bool> asmap = DecodeAsmap(asmap_path);
	if (asmap.size() == 0) {
	InitError(strprintf(_("Could not parse asmap file %s"),
	fs::quoted(fs::PathToString(asmap_path))));
	return false;
	}
	const uint256 asmap_version = SerializeHash(asmap);
	node.connman->SetAsmap(std::move(asmap));
	LogPrintf("Using asmap version %s for IP bucketing\n",
	asmap_version.ToString());
	} else {
	LogPrintf("Using /16 prefix for IP bucketing\n");
	}

	#if ENABLE_ZMQ
	g_zmq_notification_interface = CZMQNotificationInterface::Create();

	if (g_zmq_notification_interface) {
	RegisterValidationInterface(g_zmq_notification_interface);
	}
	#endif

	// Step 6.5 (I guess ?): Initialize Avalanche.
	bilingual_str avalancheError;
	g_avalanche = avalanche::Processor::MakeProcessor(
	args, *node.chain, node.connman.get(), avalancheError);
	if (!g_avalanche) {
	InitError(avalancheError);
	return false;
	}

	if (isAvalancheEnabled(args) &&
	g_avalanche->isAvalancheServiceAvailable()) {
	nLocalServices = ServiceFlags(nLocalServices \| NODE_AVALANCHE);
	}

	// Step 7: load block chain

	fReindex = args.GetBoolArg("-reindex", false);
	bool fReindexChainState = args.GetBoolArg("-reindex-chainstate", false);

	// cache size calculations
	int64_t nTotalCache = (args.GetArg("-dbcache", DEFAULT_DB_CACHE_MB) << 20);
	// total cache cannot be less than MIN_DB_CACHE_MB
	nTotalCache = std::max(nTotalCache, MIN_DB_CACHE_MB << 20);
	// total cache cannot be greater than MAX_DB_CACHE_MB
	nTotalCache = std::min(nTotalCache, MAX_DB_CACHE_MB << 20);
	int64_t nBlockTreeDBCache =
	std::min(nTotalCache / 8, MAX_BLOCK_DB_CACHE_MB << 20);
	nTotalCache -= nBlockTreeDBCache;
	int64_t nTxIndexCache =
	std::min(nTotalCache / 8, args.GetBoolArg("-txindex", DEFAULT_TXINDEX)
	? MAX_TX_INDEX_CACHE_MB << 20
	: 0);
	nTotalCache -= nTxIndexCache;
	int64_t filter_index_cache = 0;
	if (!g_enabled_filter_types.empty()) {
	size_t n_indexes = g_enabled_filter_types.size();
	int64_t max_cache =
	std::min(nTotalCache / 8, MAX_FILTER_INDEX_CACHE_MB << 20);
	filter_index_cache = max_cache / n_indexes;
	nTotalCache -= filter_index_cache * n_indexes;
	}
	// use 25%-50% of the remainder for disk cache
	int64_t nCoinDBCache =
	std::min(nTotalCache / 2, (nTotalCache / 4) + (1 << 23));
	// cap total coins db cache
	nCoinDBCache = std::min(nCoinDBCache, MAX_COINS_DB_CACHE_MB << 20);
	nTotalCache -= nCoinDBCache;
	// the rest goes to in-memory cache
	int64_t nCoinCacheUsage = nTotalCache;
	int64_t nMempoolSizeMax =
	args.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000;
	LogPrintf("Cache configuration:\n");
	LogPrintf("* Using %.1f MiB for block index database\n",
	nBlockTreeDBCache * (1.0 / 1024 / 1024));
	if (args.GetBoolArg("-txindex", DEFAULT_TXINDEX)) {
	LogPrintf("* Using %.1f MiB for transaction index database\n",
	nTxIndexCache * (1.0 / 1024 / 1024));
	}
	for (BlockFilterType filter_type : g_enabled_filter_types) {
	LogPrintf("* Using %.1f MiB for %s block filter index database\n",
	filter_index_cache * (1.0 / 1024 / 1024),
	BlockFilterTypeName(filter_type));
	}
	LogPrintf("* Using %.1f MiB for chain state database\n",
	nCoinDBCache * (1.0 / 1024 / 1024));
	LogPrintf("* Using %.1f MiB for in-memory UTXO set (plus up to %.1f MiB of "
	"unused mempool space)\n",
	nCoinCacheUsage * (1.0 / 1024 / 1024),
	nMempoolSizeMax * (1.0 / 1024 / 1024));

	bool fLoaded = false;
	while (!fLoaded && !ShutdownRequested()) {
	const bool fReset = fReindex;
	auto is_coinsview_empty =
	[&](CChainState *chainstate) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) {
	return fReset \|\| fReindexChainState \|\|
	chainstate->CoinsTip().GetBestBlock().IsNull();
	};
	bilingual_str strLoadError;

	uiInterface.InitMessage(_("Loading block index...").translated);
	do {
	bool failed_verification = false;
	const int64_t load_block_index_start_time = GetTimeMillis();
	try {
	LOCK(cs_main);
	chainman.InitializeChainstate(*Assert(node.mempool));
	chainman.m_total_coinstip_cache = nCoinCacheUsage;
	chainman.m_total_coinsdb_cache = nCoinDBCache;

	UnloadBlockIndex(node.mempool.get(), chainman);

	// new CBlockTreeDB tries to delete the existing file, which
	// fails if it's still open from the previous loop. Close it
	// first:
	pblocktree.reset();
	pblocktree.reset(
	new CBlockTreeDB(nBlockTreeDBCache, false, fReset));

	if (fReset) {
	pblocktree->WriteReindexing(true);
	// If we're reindexing in prune mode, wipe away unusable
	// block files and all undo data files
	if (fPruneMode) {
	CleanupBlockRevFiles();
	}
	}

	const Consensus::Params &params = chainparams.GetConsensus();

	// If necessary, upgrade from older database format.
	// This is a no-op if we cleared the block tree db with -reindex
	// or -reindex-chainstate
	if (!pblocktree->Upgrade(params)) {
	strLoadError = _("Error upgrading block index database");
	break;
	}

	if (ShutdownRequested()) {
	break;
	}

	// LoadBlockIndex will load fHavePruned if we've ever removed a
	// block file from disk.
	// Note that it also sets fReindex based on the disk flag!
	// From here on out fReindex and fReset mean something
	// different!
	if (!chainman.LoadBlockIndex(params)) {
	if (ShutdownRequested()) {
	break;
	}
	strLoadError = _("Error loading block database");
	break;
	}

	// If the loaded chain has a wrong genesis, bail out immediately
	// (we're likely using a testnet datadir, or the other way
	// around).
	if (!chainman.BlockIndex().empty() &&
	!LookupBlockIndex(params.hashGenesisBlock)) {
	return InitError(_("Incorrect or no genesis block found. "
	"Wrong datadir for network?"));
	}

	// Check for changed -prune state. What we are concerned about
	// is a user who has pruned blocks in the past, but is now
	// trying to run unpruned.
	if (fHavePruned && !fPruneMode) {
	strLoadError =
	_("You need to rebuild the database using -reindex to "
	"go back to unpruned mode. This will redownload the "
	"entire blockchain");
	break;
	}

	// At this point blocktree args are consistent with what's on
	// disk. If we're not mid-reindex (based on disk + args), add a
	// genesis block on disk (otherwise we use the one already on
	// disk).
	// This is called again in ThreadImport after the reindex
	// completes.
	if (!fReindex && !LoadGenesisBlock(chainparams)) {
	strLoadError = _("Error initializing block database");
	break;
	}

	// At this point we're either in reindex or we've loaded a
	// useful block tree into BlockIndex()!

	bool failed_chainstate_init = false;

	for (CChainState *chainstate : chainman.GetAll()) {
	chainstate->InitCoinsDB(
	/* cache_size_bytes */ nCoinDBCache,
	/* in_memory */ false,
	/* should_wipe */ fReset \|\| fReindexChainState);

	chainstate->CoinsErrorCatcher().AddReadErrCallback([]() {
	uiInterface.ThreadSafeMessageBox(
	_("Error reading from database, shutting down."),
	"", CClientUIInterface::MSG_ERROR);
	});

	// If necessary, upgrade from older database format.
	// This is a no-op if we cleared the coinsviewdb with
	// -reindex or -reindex-chainstate
	if (!chainstate->CoinsDB().Upgrade()) {
	strLoadError = _("Error upgrading chainstate database");
	failed_chainstate_init = true;
	break;
	}

	// ReplayBlocks is a no-op if we cleared the coinsviewdb
	// with -reindex or -reindex-chainstate
	if (!chainstate->ReplayBlocks(params)) {
	strLoadError = _(
	"Unable to replay blocks. You will need to rebuild "
	"the database using -reindex-chainstate.");
	failed_chainstate_init = true;
	break;
	}

	// The on-disk coinsdb is now in a good state, create the
	// cache
	chainstate->InitCoinsCache(nCoinCacheUsage);
	assert(chainstate->CanFlushToDisk());

	if (!is_coinsview_empty(chainstate)) {
	// LoadChainTip initializes the chain based on
	// CoinsTip()'s best block
	if (!chainstate->LoadChainTip(chainparams)) {
	strLoadError =
	_("Error initializing block database");
	failed_chainstate_init = true;
	// out of the per-chainstate loop
	break;
	}
	assert(chainstate->m_chain.Tip() != nullptr);
	}
	}

	if (failed_chainstate_init) {
	// out of the chainstate activation do-while
	break;
	}

	for (CChainState *chainstate : chainman.GetAll()) {
	if (!is_coinsview_empty(chainstate)) {
	uiInterface.InitMessage(
	_("Verifying blocks...").translated);
	if (fHavePruned &&
	args.GetArg("-checkblocks", DEFAULT_CHECKBLOCKS) >
	MIN_BLOCKS_TO_KEEP) {
	LogPrintf(
	"Prune: pruned datadir may not have more than "
	"%d blocks; only checking available blocks\n",
	MIN_BLOCKS_TO_KEEP);
	}

	const CBlockIndex *tip = chainstate->m_chain.Tip();
	RPCNotifyBlockChange(tip);
	if (tip &&
	tip->nTime > GetAdjustedTime() + 2 * 60 * 60) {
	strLoadError =
	_("The block database contains a block which "
	"appears to be from the future. "
	"This may be due to your computer's date and "
	"time being set incorrectly. "
	"Only rebuild the block database if you are "
	"sure that your computer's date and time are "
	"correct");
	failed_verification = true;
	break;
	}

	// Only verify the DB of the active chainstate. This is
	// fixed in later work when we allow VerifyDB to be
	// parameterized by chainstate.
	if (&::ChainstateActive() == chainstate &&
	!CVerifyDB().VerifyDB(
	config, &chainstate->CoinsDB(),
	args.GetArg("-checklevel", DEFAULT_CHECKLEVEL),
	args.GetArg("-checkblocks",
	DEFAULT_CHECKBLOCKS))) {
	strLoadError =
	_("Corrupted block database detected");
	failed_verification = true;
	break;
	}
	}
	}
	} catch (const std::exception &e) {
	LogPrintf("%s\n", e.what());
	strLoadError = _("Error opening block database");
	failed_verification = true;
	break;
	}

	if (!failed_verification) {
	fLoaded = true;
	LogPrintf(" block index %15dms\n",
	GetTimeMillis() - load_block_index_start_time);
	}
	} while (false);

	if (!fLoaded && !ShutdownRequested()) {
	// first suggest a reindex
	if (!fReset) {
	bool fRet = uiInterface.ThreadSafeQuestion(
	strLoadError + Untranslated(".\n\n") +
	_("Do you want to rebuild the block database now?"),
	strLoadError.original +
	".\nPlease restart with -reindex or "
	"-reindex-chainstate to recover.",
	"",
	CClientUIInterface::MSG_ERROR \|
	CClientUIInterface::BTN_ABORT);
	if (fRet) {
	fReindex = true;
	AbortShutdown();
	} else {
	LogPrintf("Aborted block database rebuild. Exiting.\n");
	return false;
	}
	} else {
	return InitError(strLoadError);
	}
	}
	}

	// As LoadBlockIndex can take several minutes, it's possible the user
	// requested to kill the GUI during the last operation. If so, exit.
	// As the program has not fully started yet, Shutdown() is possibly
	// overkill.
	if (ShutdownRequested()) {
	LogPrintf("Shutdown requested. Exiting.\n");
	return false;
	}

	// Encoded addresses using cashaddr instead of base58.
	// We do this by default to avoid confusion with BTC addresses.
	config.SetCashAddrEncoding(args.GetBoolArg("-usecashaddr", true));

	// Step 8: load indexers
	if (args.GetBoolArg("-txindex", DEFAULT_TXINDEX)) {
	g_txindex = std::make_unique<TxIndex>(nTxIndexCache, false, fReindex);
	g_txindex->Start();
	}

	for (const auto &filter_type : g_enabled_filter_types) {
	InitBlockFilterIndex(filter_type, filter_index_cache, false, fReindex);
	GetBlockFilterIndex(filter_type)->Start();
	}

	// Step 9: load wallet
	for (const auto &client : node.chain_clients) {
	if (!client->load()) {
	return false;
	}
	}

	// Step 10: data directory maintenance

	// if pruning, unset the service bit and perform the initial blockstore
	// prune after any wallet rescanning has taken place.
	if (fPruneMode) {
	LogPrintf("Unsetting NODE_NETWORK on prune mode\n");
	nLocalServices = ServiceFlags(nLocalServices & ~NODE_NETWORK);
	if (!fReindex) {
	LOCK(cs_main);
	for (CChainState *chainstate : chainman.GetAll()) {
	uiInterface.InitMessage(_("Pruning blockstore...").translated);
	chainstate->PruneAndFlush();
	}
	}
	}

	// Step 11: import blocks
	if (!CheckDiskSpace(GetDataDir())) {
	InitError(strprintf(_("Error: Disk space is low for %s"),
	fs::quoted(fs::PathToString(GetDataDir()))));
	return false;
	}
	if (!CheckDiskSpace(gArgs.GetBlocksDirPath())) {
	InitError(
	strprintf(_("Error: Disk space is low for %s"),
	fs::quoted(fs::PathToString(gArgs.GetBlocksDirPath()))));
	return false;
	}

	// Either install a handler to notify us when genesis activates, or set
	// fHaveGenesis directly.
	// No locking, as this happens before any background thread is started.
	boost::signals2::connection block_notify_genesis_wait_connection;
	if (::ChainActive().Tip() == nullptr) {
	block_notify_genesis_wait_connection =
	uiInterface.NotifyBlockTip_connect(
	std::bind(BlockNotifyGenesisWait, std::placeholders::_2));
	} else {
	fHaveGenesis = true;
	}

	#if defined(HAVE_SYSTEM)
	const std::string block_notify = args.GetArg("-blocknotify", "");
	if (!block_notify.empty()) {
	uiInterface.NotifyBlockTip_connect([block_notify](
	SynchronizationState sync_state,
	const CBlockIndex *pBlockIndex) {
	if (sync_state != SynchronizationState::POST_INIT \|\| !pBlockIndex) {
	return;
	}
	std::string command = block_notify;
	boost::replace_all(command, "%s",
	pBlockIndex->GetBlockHash().GetHex());
	std::thread t(runCommand, command);
	// thread runs free
	t.detach();
	});
	}
	#endif

	std::vector<fs::path> vImportFiles;
	for (const std::string &strFile : args.GetArgs("-loadblock")) {
	vImportFiles.push_back(fs::PathFromString(strFile));
	}

	g_load_block =
	std::thread(&TraceThread<std::function<void()>>, "loadblk",
	[=, &config, &chainman, &args] {
	ThreadImport(config, chainman, vImportFiles, args);
	});

	// Wait for genesis block to be processed
	{
	WAIT_LOCK(g_genesis_wait_mutex, lock);
	// We previously could hang here if StartShutdown() is called prior to
	// ThreadImport getting started, so instead we just wait on a timer to
	// check ShutdownRequested() regularly.
	while (!fHaveGenesis && !ShutdownRequested()) {
	g_genesis_wait_cv.wait_for(lock, std::chrono::milliseconds(500));
	}
	block_notify_genesis_wait_connection.disconnect();
	}

	if (ShutdownRequested()) {
	return false;
	}

	// Step 12: start node

	int chain_active_height;

	//// debug print
	{
	LOCK(cs_main);
	LogPrintf("block tree size = %u\n", chainman.BlockIndex().size());
	chain_active_height = chainman.ActiveChain().Height();
	if (tip_info) {
	tip_info->block_height = chain_active_height;
	tip_info->block_time =
	chainman.ActiveChain().Tip()
	? chainman.ActiveChain().Tip()->GetBlockTime()
	: Params().GenesisBlock().GetBlockTime();
	tip_info->verification_progress = GuessVerificationProgress(
	Params().TxData(), chainman.ActiveChain().Tip());
	}
	if (tip_info && ::pindexBestHeader) {
	tip_info->header_height = ::pindexBestHeader->nHeight;
	tip_info->header_time = ::pindexBestHeader->GetBlockTime();
	}
	}
	LogPrintf("nBestHeight = %d\n", chain_active_height);
	if (node.peerman) {
	node.peerman->SetBestHeight(chain_active_height);
	}

	Discover();

	// Map ports with UPnP
	if (args.GetBoolArg("-upnp", DEFAULT_UPNP)) {
	StartMapPort();
	}

	CConnman::Options connOptions;
	connOptions.nLocalServices = nLocalServices;
	connOptions.nMaxConnections = nMaxConnections;
	connOptions.m_max_outbound_full_relay = std::min(
	MAX_OUTBOUND_FULL_RELAY_CONNECTIONS, connOptions.nMaxConnections);
	connOptions.m_max_outbound_block_relay = std::min(
	MAX_BLOCK_RELAY_ONLY_CONNECTIONS,
	connOptions.nMaxConnections - connOptions.m_max_outbound_full_relay);
	connOptions.nMaxAddnode = MAX_ADDNODE_CONNECTIONS;
	connOptions.nMaxFeeler = MAX_FEELER_CONNECTIONS;
	connOptions.uiInterface = &uiInterface;
	connOptions.m_banman = node.banman.get();
	connOptions.m_msgproc = node.peerman.get();
	connOptions.nSendBufferMaxSize =
	1000 * args.GetArg("-maxsendbuffer", DEFAULT_MAXSENDBUFFER);
	connOptions.nReceiveFloodSize =
	1000 * args.GetArg("-maxreceivebuffer", DEFAULT_MAXRECEIVEBUFFER);
	connOptions.m_added_nodes = args.GetArgs("-addnode");

	connOptions.nMaxOutboundLimit =
	1024 * 1024 *
	args.GetArg("-maxuploadtarget", DEFAULT_MAX_UPLOAD_TARGET);
	connOptions.m_peer_connect_timeout = peer_connect_timeout;

	for (const std::string &bind_arg : args.GetArgs("-bind")) {
	CService bind_addr;
	const size_t index = bind_arg.rfind('=');
	if (index == std::string::npos) {
	if (Lookup(bind_arg, bind_addr, GetListenPort(), false)) {
	connOptions.vBinds.push_back(bind_addr);
	continue;
	}
	} else {
	const std::string network_type = bind_arg.substr(index + 1);
	if (network_type == "onion") {
	const std::string truncated_bind_arg =
	bind_arg.substr(0, index);
	if (Lookup(truncated_bind_arg, bind_addr,
	BaseParams().OnionServiceTargetPort(), false)) {
	connOptions.onion_binds.push_back(bind_addr);
	continue;
	}
	}
	}
	return InitError(ResolveErrMsg("bind", bind_arg));
	}

	if (connOptions.onion_binds.empty()) {
	connOptions.onion_binds.push_back(DefaultOnionServiceTarget());
	}

	if (args.GetBoolArg("-listenonion", DEFAULT_LISTEN_ONION)) {
	const auto bind_addr = connOptions.onion_binds.front();
	if (connOptions.onion_binds.size() > 1) {
	InitWarning(strprintf(
	_("More than one onion bind address is provided. Using %s for "
	"the automatically created Tor onion service."),
	bind_addr.ToStringIPPort()));
	}
	StartTorControl(bind_addr);
	}

	for (const std::string &strBind : args.GetArgs("-whitebind")) {
	NetWhitebindPermissions whitebind;
	bilingual_str error;
	if (!NetWhitebindPermissions::TryParse(strBind, whitebind, error)) {
	return InitError(error);
	}
	connOptions.vWhiteBinds.push_back(whitebind);
	}

	for (const auto &net : args.GetArgs("-whitelist")) {
	NetWhitelistPermissions subnet;
	bilingual_str error;
	if (!NetWhitelistPermissions::TryParse(net, subnet, error)) {
	return InitError(error);
	}
	connOptions.vWhitelistedRange.push_back(subnet);
	}

	connOptions.vSeedNodes = args.GetArgs("-seednode");

	// Initiate outbound connections unless connect=0
	connOptions.m_use_addrman_outgoing = !args.IsArgSet("-connect");
	if (!connOptions.m_use_addrman_outgoing) {
	const auto connect = args.GetArgs("-connect");
	if (connect.size() != 1 \|\| connect[0] != "0") {
	connOptions.m_specified_outgoing = connect;
	}
	}
	if (!node.connman->Start(*node.scheduler, connOptions)) {
	return false;
	}

	// Step 13: finished

	SetRPCWarmupFinished();
	uiInterface.InitMessage(_("Done loading").translated);

	for (const auto &client : node.chain_clients) {
	client->start(*node.scheduler);
	}

	BanMan *banman = node.banman.get();
	node.scheduler->scheduleEvery(
	[banman] {
	banman->DumpBanlist();
	return true;
	},
	DUMP_BANS_INTERVAL);

	// Start Avalanche's event loop.
	g_avalanche->startEventLoop(*node.scheduler);

	#if HAVE_SYSTEM
	StartupNotify(args);
	#endif

	return true;
	}
	diff --git a/src/test/checkqueue_tests.cpp b/src/test/checkqueue_tests.cpp
	index 0db0b5fa1..8b8605033 100644
	--- a/src/test/checkqueue_tests.cpp
	+++ b/src/test/checkqueue_tests.cpp
	@@ -1,422 +1,397 @@
	// Copyright (c) 2012-2019 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 <checkqueue.h>

	#include <sync.h>
	#include <util/system.h>
	#include <util/time.h>

	#include <atomic>
	#include <condition_variable>
	#include <mutex>
	#include <test/util/setup_common.h>
	#include <thread>
	#include <vector>

	#include <boost/test/unit_test.hpp>

	#include <memory>
	#include <unordered_set>
	#include <utility>

	BOOST_FIXTURE_TEST_SUITE(checkqueue_tests, TestingSetup)

	static const unsigned int QUEUE_BATCH_SIZE = 128;
	static const int SCRIPT_CHECK_THREADS = 3;

	struct FakeCheck {
	bool operator()() { return true; }
	void swap(FakeCheck &x){};
	};

	struct FakeCheckCheckCompletion {
	static std::atomic<size_t> n_calls;
	bool operator()() {
	n_calls.fetch_add(1, std::memory_order_relaxed);
	return true;
	}
	void swap(FakeCheckCheckCompletion &x){};
	};

	struct FailingCheck {
	bool fails;
	FailingCheck(bool _fails) : fails(_fails){};
	FailingCheck() : fails(true){};
	bool operator()() { return !fails; }
	void swap(FailingCheck &x) { std::swap(fails, x.fails); };
	};

	struct UniqueCheck {
	static Mutex m;
	static std::unordered_multiset<size_t> results GUARDED_BY(m);
	size_t check_id;
	UniqueCheck(size_t check_id_in) : check_id(check_id_in){};
	UniqueCheck() : check_id(0){};
	bool operator()() {
	LOCK(m);
	results.insert(check_id);
	return true;
	}
	void swap(UniqueCheck &x) { std::swap(x.check_id, check_id); };
	};

	struct MemoryCheck {
	static std::atomic<size_t> fake_allocated_memory;
	bool b{false};
	bool operator()() { return true; }
	MemoryCheck(){};
	MemoryCheck(const MemoryCheck &x) {
	// We have to do this to make sure that destructor calls are paired
	//
	// Really, copy constructor should be deletable, but CCheckQueue breaks
	// if it is deleted because of internal push_back.
	fake_allocated_memory.fetch_add(b, std::memory_order_relaxed);
	};
	MemoryCheck(bool b_) : b(b_) {
	fake_allocated_memory.fetch_add(b, std::memory_order_relaxed);
	};
	~MemoryCheck() {
	fake_allocated_memory.fetch_sub(b, std::memory_order_relaxed);
	};
	void swap(MemoryCheck &x) { std::swap(b, x.b); };
	};

	struct FrozenCleanupCheck {
	static std::atomic<uint64_t> nFrozen;
	static std::condition_variable cv;
	static std::mutex m;
	// Freezing can't be the default initialized behavior given how the queue
	// swaps in default initialized Checks.
	bool should_freeze{false};
	bool operator()() { return true; }
	FrozenCleanupCheck() {}
	~FrozenCleanupCheck() {
	if (should_freeze) {
	std::unique_lock<std::mutex> l(m);
	nFrozen.store(1, std::memory_order_relaxed);
	cv.notify_one();
	cv.wait(
	l, [] { return nFrozen.load(std::memory_order_relaxed) == 0; });
	}
	}
	void swap(FrozenCleanupCheck &x) {
	std::swap(should_freeze, x.should_freeze);
	};
	};

	// Static Allocations
	std::mutex FrozenCleanupCheck::m{};
	std::atomic<uint64_t> FrozenCleanupCheck::nFrozen{0};
	std::condition_variable FrozenCleanupCheck::cv{};
	Mutex UniqueCheck::m;
	std::unordered_multiset<size_t> UniqueCheck::results;
	std::atomic<size_t> FakeCheckCheckCompletion::n_calls{0};
	std::atomic<size_t> MemoryCheck::fake_allocated_memory{0};

	// Queue Typedefs
	typedef CCheckQueue<FakeCheckCheckCompletion> Correct_Queue;
	typedef CCheckQueue<FakeCheck> Standard_Queue;
	typedef CCheckQueue<FailingCheck> Failing_Queue;
	typedef CCheckQueue<UniqueCheck> Unique_Queue;
	typedef CCheckQueue<MemoryCheck> Memory_Queue;
	typedef CCheckQueue<FrozenCleanupCheck> FrozenCleanup_Queue;

	/** This test case checks that the CCheckQueue works properly
	* with each specified size_t Checks pushed.
	*/
	static void Correct_Queue_range(std::vector<size_t> range) {
	auto small_queue = std::make_unique<Correct_Queue>(QUEUE_BATCH_SIZE);
	- boost::thread_group tg;
	- for (auto x = 0; x < SCRIPT_CHECK_THREADS; ++x) {
	- tg.create_thread([&] { small_queue->Thread(); });
	- }
	+ small_queue->StartWorkerThreads(SCRIPT_CHECK_THREADS);
	// Make vChecks here to save on malloc (this test can be slow...)
	std::vector<FakeCheckCheckCompletion> vChecks;
	for (const size_t i : range) {
	size_t total = i;
	FakeCheckCheckCompletion::n_calls = 0;
	CCheckQueueControl<FakeCheckCheckCompletion> control(small_queue.get());
	while (total) {
	vChecks.resize(std::min(total, (size_t)InsecureRandRange(10)));
	total -= vChecks.size();
	control.Add(vChecks);
	}
	BOOST_REQUIRE(control.Wait());
	if (FakeCheckCheckCompletion::n_calls != i) {
	BOOST_REQUIRE_EQUAL(FakeCheckCheckCompletion::n_calls, i);
	}
	}
	- tg.interrupt_all();
	- tg.join_all();
	+ small_queue->StopWorkerThreads();
	}

	/** Test that 0 checks is correct
	*/
	BOOST_AUTO_TEST_CASE(test_CheckQueue_Correct_Zero) {
	std::vector<size_t> range;
	range.push_back((size_t)0);
	Correct_Queue_range(range);
	}
	/** Test that 1 check is correct
	*/
	BOOST_AUTO_TEST_CASE(test_CheckQueue_Correct_One) {
	std::vector<size_t> range;
	range.push_back((size_t)1);
	Correct_Queue_range(range);
	}
	/** Test that MAX check is correct
	*/
	BOOST_AUTO_TEST_CASE(test_CheckQueue_Correct_Max) {
	std::vector<size_t> range;
	range.push_back(100000);
	Correct_Queue_range(range);
	}
	/** Test that random numbers of checks are correct
	*/
	BOOST_AUTO_TEST_CASE(test_CheckQueue_Correct_Random) {
	std::vector<size_t> range;
	range.reserve(100000 / 1000);
	for (size_t i = 2; i < 100000;
	i += std::max((size_t)1, (size_t)InsecureRandRange(std::min(
	(size_t)1000, ((size_t)100000) - i)))) {
	range.push_back(i);
	}
	Correct_Queue_range(range);
	}

	/** Test that failing checks are caught */
	BOOST_AUTO_TEST_CASE(test_CheckQueue_Catches_Failure) {
	auto fail_queue = std::make_unique<Failing_Queue>(QUEUE_BATCH_SIZE);
	-
	- boost::thread_group tg;
	- for (auto x = 0; x < SCRIPT_CHECK_THREADS; ++x) {
	- tg.create_thread([&] { fail_queue->Thread(); });
	- }
	+ fail_queue->StartWorkerThreads(SCRIPT_CHECK_THREADS);

	for (size_t i = 0; i < 1001; ++i) {
	CCheckQueueControl<FailingCheck> control(fail_queue.get());
	size_t remaining = i;
	while (remaining) {
	size_t r = InsecureRandRange(10);

	std::vector<FailingCheck> vChecks;
	vChecks.reserve(r);
	for (size_t k = 0; k < r && remaining; k++, remaining--) {
	vChecks.emplace_back(remaining == 1);
	}
	control.Add(vChecks);
	}
	bool success = control.Wait();
	if (i > 0) {
	BOOST_REQUIRE(!success);
	} else if (i == 0) {
	BOOST_REQUIRE(success);
	}
	}
	- tg.interrupt_all();
	- tg.join_all();
	+ fail_queue->StopWorkerThreads();
	}
	// Test that a block validation which fails does not interfere with
	// future blocks, ie, the bad state is cleared.
	BOOST_AUTO_TEST_CASE(test_CheckQueue_Recovers_From_Failure) {
	auto fail_queue = std::make_unique<Failing_Queue>(QUEUE_BATCH_SIZE);
	- boost::thread_group tg;
	- for (auto x = 0; x < SCRIPT_CHECK_THREADS; ++x) {
	- tg.create_thread([&] { fail_queue->Thread(); });
	- }
	+ fail_queue->StartWorkerThreads(SCRIPT_CHECK_THREADS);

	for (auto times = 0; times < 10; ++times) {
	for (const bool end_fails : {true, false}) {
	CCheckQueueControl<FailingCheck> control(fail_queue.get());
	{
	std::vector<FailingCheck> vChecks;
	vChecks.resize(100, false);
	vChecks[99] = end_fails;
	control.Add(vChecks);
	}
	bool r = control.Wait();
	BOOST_REQUIRE(r != end_fails);
	}
	}
	- tg.interrupt_all();
	- tg.join_all();
	+ fail_queue->StopWorkerThreads();
	}

	// Test that unique checks are actually all called individually, rather than
	// just one check being called repeatedly. Test that checks are not called
	// more than once as well
	BOOST_AUTO_TEST_CASE(test_CheckQueue_UniqueCheck) {
	auto queue = std::make_unique<Unique_Queue>(QUEUE_BATCH_SIZE);
	- boost::thread_group tg;
	- for (auto x = 0; x < SCRIPT_CHECK_THREADS; ++x) {
	- tg.create_thread([&] { queue->Thread(); });
	- }
	+ queue->StartWorkerThreads(SCRIPT_CHECK_THREADS);

	size_t COUNT = 100000;
	size_t total = COUNT;
	{
	CCheckQueueControl<UniqueCheck> control(queue.get());
	while (total) {
	size_t r = InsecureRandRange(10);
	std::vector<UniqueCheck> vChecks;
	for (size_t k = 0; k < r && total; k++) {
	vChecks.emplace_back(--total);
	}
	control.Add(vChecks);
	}
	}
	{
	LOCK(UniqueCheck::m);
	bool r = true;
	BOOST_REQUIRE_EQUAL(UniqueCheck::results.size(), COUNT);
	for (size_t i = 0; i < COUNT; ++i) {
	r = r && UniqueCheck::results.count(i) == 1;
	}
	BOOST_REQUIRE(r);
	}
	- tg.interrupt_all();
	- tg.join_all();
	+ queue->StopWorkerThreads();
	}

	// Test that blocks which might allocate lots of memory free their memory
	// aggressively.
	//
	// This test attempts to catch a pathological case where by lazily freeing
	// checks might mean leaving a check un-swapped out, and decreasing by 1 each
	// time could leave the data hanging across a sequence of blocks.
	BOOST_AUTO_TEST_CASE(test_CheckQueue_Memory) {
	auto queue = std::make_unique<Memory_Queue>(QUEUE_BATCH_SIZE);
	- boost::thread_group tg;
	- for (auto x = 0; x < SCRIPT_CHECK_THREADS; ++x) {
	- tg.create_thread([&] { queue->Thread(); });
	- }
	+ queue->StartWorkerThreads(SCRIPT_CHECK_THREADS);
	for (size_t i = 0; i < 1000; ++i) {
	size_t total = i;
	{
	CCheckQueueControl<MemoryCheck> control(queue.get());
	while (total) {
	size_t r = InsecureRandRange(10);
	std::vector<MemoryCheck> vChecks;
	for (size_t k = 0; k < r && total; k++) {
	total--;
	// Each iteration leaves data at the front, back, and middle
	// to catch any sort of deallocation failure
	vChecks.emplace_back(total == 0 \|\| total == i \|\|
	total == i / 2);
	}
	control.Add(vChecks);
	}
	}
	BOOST_REQUIRE_EQUAL(MemoryCheck::fake_allocated_memory, 0U);
	}
	- tg.interrupt_all();
	- tg.join_all();
	+ queue->StopWorkerThreads();
	}

	// Test that a new verification cannot occur until all checks
	// have been destructed
	BOOST_AUTO_TEST_CASE(test_CheckQueue_FrozenCleanup) {
	auto queue = std::make_unique<FrozenCleanup_Queue>(QUEUE_BATCH_SIZE);
	- boost::thread_group tg;
	bool fails = false;
	- for (auto x = 0; x < SCRIPT_CHECK_THREADS; ++x) {
	- tg.create_thread([&] { queue->Thread(); });
	- }
	+ queue->StartWorkerThreads(SCRIPT_CHECK_THREADS);
	std::thread t0([&]() {
	CCheckQueueControl<FrozenCleanupCheck> control(queue.get());
	std::vector<FrozenCleanupCheck> vChecks(1);
	// Freezing can't be the default initialized behavior given how the
	// queue
	// swaps in default initialized Checks (otherwise freezing destructor
	// would get called twice).
	vChecks[0].should_freeze = true;
	control.Add(vChecks);
	// Hangs here
	bool waitResult = control.Wait();
	assert(waitResult);
	});
	{
	std::unique_lock<std::mutex> l(FrozenCleanupCheck::m);
	// Wait until the queue has finished all jobs and frozen
	FrozenCleanupCheck::cv.wait(
	l, []() { return FrozenCleanupCheck::nFrozen == 1; });
	}
	// Try to get control of the queue a bunch of times
	for (auto x = 0; x < 100 && !fails; ++x) {
	fails = queue->ControlMutex.try_lock();
	}
	{
	// Unfreeze (we need lock n case of spurious wakeup)
	std::unique_lock<std::mutex> l(FrozenCleanupCheck::m);
	FrozenCleanupCheck::nFrozen = 0;
	}
	// Awaken frozen destructor
	FrozenCleanupCheck::cv.notify_one();
	// Wait for control to finish
	t0.join();
	- tg.interrupt_all();
	- tg.join_all();
	BOOST_REQUIRE(!fails);
	+ queue->StopWorkerThreads();
	}

	/** Test that CCheckQueueControl is threadsafe */
	BOOST_AUTO_TEST_CASE(test_CheckQueueControl_Locks) {
	auto queue = std::make_unique<Standard_Queue>(QUEUE_BATCH_SIZE);
	{
	boost::thread_group tg;
	std::atomic<int> nThreads{0};
	std::atomic<int> fails{0};
	for (size_t i = 0; i < 3; ++i) {
	tg.create_thread([&] {
	CCheckQueueControl<FakeCheck> control(queue.get());
	// While sleeping, no other thread should execute to this point
	auto observed = ++nThreads;
	UninterruptibleSleep(std::chrono::milliseconds{10});
	fails += observed != nThreads;
	});
	}
	tg.join_all();
	BOOST_REQUIRE_EQUAL(fails, 0);
	}
	{
	boost::thread_group tg;
	std::mutex m;
	std::condition_variable cv;
	bool has_lock{false};
	bool has_tried{false};
	bool done{false};
	bool done_ack{false};
	{
	std::unique_lock<std::mutex> l(m);
	tg.create_thread([&] {
	CCheckQueueControl<FakeCheck> control(queue.get());
	std::unique_lock<std::mutex> ll(m);
	has_lock = true;
	cv.notify_one();
	cv.wait(ll, [&] { return has_tried; });
	done = true;
	cv.notify_one();
	// Wait until the done is acknowledged
	//
	cv.wait(ll, [&] { return done_ack; });
	});
	// Wait for thread to get the lock
	cv.wait(l, [&]() { return has_lock; });
	bool fails = false;
	for (auto x = 0; x < 100 && !fails; ++x) {
	fails = queue->ControlMutex.try_lock();
	}
	has_tried = true;
	cv.notify_one();
	cv.wait(l, [&]() { return done; });
	// Acknowledge the done
	done_ack = true;
	cv.notify_one();
	BOOST_REQUIRE(!fails);
	}
	tg.join_all();
	}
	}
	BOOST_AUTO_TEST_SUITE_END()
	diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp
	index fb8abe5f7..b1693b8f4 100644
	--- a/src/test/transaction_tests.cpp
	+++ b/src/test/transaction_tests.cpp
	@@ -1,939 +1,933 @@
	// Copyright (c) 2011-2019 The Bitcoin Core developers
	// Copyright (c) 2017-2020 The Bitcoin developers
	// Distributed under the MIT software license, see the accompanying
	// file COPYING or http://www.opensource.org/licenses/mit-license.php.

	#include <chainparams.h> // For CChainParams
	#include <checkqueue.h>
	#include <clientversion.h>
	#include <config.h>
	#include <consensus/tx_check.h>
	#include <consensus/tx_verify.h>
	#include <consensus/validation.h>
	#include <core_io.h>
	#include <key.h>
	#include <policy/policy.h>
	#include <policy/settings.h>
	#include <script/script.h>
	#include <script/script_error.h>
	#include <script/sign.h>
	#include <script/signingprovider.h>
	#include <script/standard.h>
	#include <streams.h>
	#include <util/strencodings.h>
	#include <util/string.h>
	#include <util/system.h>
	#include <validation.h>

	#include <test/data/tx_invalid.json.h>
	#include <test/data/tx_valid.json.h>
	#include <test/jsonutil.h>
	#include <test/scriptflags.h>
	#include <test/util/setup_common.h>
	#include <test/util/transaction_utils.h>

	#include <boost/test/unit_test.hpp>

	#include <univalue.h>

	#include <map>
	#include <string>

	typedef std::vector<uint8_t> valtype;

	BOOST_FIXTURE_TEST_SUITE(transaction_tests, BasicTestingSetup)

	static COutPoint buildOutPoint(const UniValue &vinput) {
	TxId txid;
	txid.SetHex(vinput[0].get_str());
	return COutPoint(txid, vinput[1].get_int());
	}

	BOOST_AUTO_TEST_CASE(tx_valid) {
	// Read tests from test/data/tx_valid.json
	// Format is an array of arrays
	// Inner arrays are either [ "comment" ]
	// or [[[prevout hash, prevout index, prevout scriptPubKey], [input 2],
	// ...],"], serializedTransaction, verifyFlags
	// ... where all scripts are stringified scripts.
	//
	// verifyFlags is a comma separated list of script verification flags to
	// apply, or "NONE"
	UniValue tests = read_json(
	std::string(json_tests::tx_valid,
	json_tests::tx_valid + sizeof(json_tests::tx_valid)));

	ScriptError err;
	for (size_t idx = 0; idx < tests.size(); idx++) {
	UniValue test = tests[idx];
	std::string strTest = test.write();
	if (test[0].isArray()) {
	if (test.size() != 3 \|\| !test[1].isStr() \|\| !test[2].isStr()) {
	BOOST_ERROR("Bad test: " << strTest);
	continue;
	}

	std::map<COutPoint, CScript> mapprevOutScriptPubKeys;
	std::map<COutPoint, Amount> mapprevOutValues;
	UniValue inputs = test[0].get_array();
	bool fValid = true;
	for (size_t inpIdx = 0; inpIdx < inputs.size(); inpIdx++) {
	const UniValue &input = inputs[inpIdx];
	if (!input.isArray()) {
	fValid = false;
	break;
	}
	UniValue vinput = input.get_array();
	if (vinput.size() < 3 \|\| vinput.size() > 4) {
	fValid = false;
	break;
	}
	COutPoint outpoint = buildOutPoint(vinput);
	mapprevOutScriptPubKeys[outpoint] =
	ParseScript(vinput[2].get_str());
	if (vinput.size() >= 4) {
	mapprevOutValues[outpoint] =
	vinput[3].get_int64() * SATOSHI;
	}
	}
	if (!fValid) {
	BOOST_ERROR("Bad test: " << strTest);
	continue;
	}

	std::string transaction = test[1].get_str();
	CDataStream stream(ParseHex(transaction), SER_NETWORK,
	PROTOCOL_VERSION);
	CTransaction tx(deserialize, stream);

	TxValidationState state;
	BOOST_CHECK_MESSAGE(tx.IsCoinBase()
	? CheckCoinbase(tx, state)
	: CheckRegularTransaction(tx, state),
	strTest);
	BOOST_CHECK(state.IsValid());

	// Check that CheckCoinbase reject non-coinbase transactions and
	// vice versa.
	BOOST_CHECK_MESSAGE(!(tx.IsCoinBase()
	? CheckRegularTransaction(tx, state)
	: CheckCoinbase(tx, state)),
	strTest);
	BOOST_CHECK(state.IsInvalid());

	PrecomputedTransactionData txdata(tx);
	for (size_t i = 0; i < tx.vin.size(); i++) {
	if (!mapprevOutScriptPubKeys.count(tx.vin[i].prevout)) {
	BOOST_ERROR("Bad test: " << strTest);
	break;
	}

	Amount amount = Amount::zero();
	if (mapprevOutValues.count(tx.vin[i].prevout)) {
	amount = mapprevOutValues[tx.vin[i].prevout];
	}

	uint32_t verify_flags = ParseScriptFlags(test[2].get_str());
	BOOST_CHECK_MESSAGE(
	VerifyScript(
	tx.vin[i].scriptSig,
	mapprevOutScriptPubKeys[tx.vin[i].prevout],
	verify_flags,
	TransactionSignatureChecker(&tx, i, amount, txdata),
	&err),
	strTest);
	BOOST_CHECK_MESSAGE(err == ScriptError::OK,
	ScriptErrorString(err));
	}
	}
	}
	}

	BOOST_AUTO_TEST_CASE(tx_invalid) {
	// Read tests from test/data/tx_invalid.json
	// Format is an array of arrays
	// Inner arrays are either [ "comment" ]
	// or [[[prevout hash, prevout index, prevout scriptPubKey], [input 2],
	// ...],"], serializedTransaction, verifyFlags
	// ... where all scripts are stringified scripts.
	//
	// verifyFlags is a comma separated list of script verification flags to
	// apply, or "NONE"
	UniValue tests = read_json(
	std::string(json_tests::tx_invalid,
	json_tests::tx_invalid + sizeof(json_tests::tx_invalid)));

	// Initialize to ScriptError::OK. The tests expect err to be changed to a
	// value other than ScriptError::OK.
	ScriptError err = ScriptError::OK;
	for (size_t idx = 0; idx < tests.size(); idx++) {
	UniValue test = tests[idx];
	std::string strTest = test.write();
	if (test[0].isArray()) {
	if (test.size() != 3 \|\| !test[1].isStr() \|\| !test[2].isStr()) {
	BOOST_ERROR("Bad test: " << strTest);
	continue;
	}

	std::map<COutPoint, CScript> mapprevOutScriptPubKeys;
	std::map<COutPoint, Amount> mapprevOutValues;
	UniValue inputs = test[0].get_array();
	bool fValid = true;
	for (size_t inpIdx = 0; inpIdx < inputs.size(); inpIdx++) {
	const UniValue &input = inputs[inpIdx];
	if (!input.isArray()) {
	fValid = false;
	break;
	}
	UniValue vinput = input.get_array();
	if (vinput.size() < 3 \|\| vinput.size() > 4) {
	fValid = false;
	break;
	}
	COutPoint outpoint = buildOutPoint(vinput);
	mapprevOutScriptPubKeys[outpoint] =
	ParseScript(vinput[2].get_str());
	if (vinput.size() >= 4) {
	mapprevOutValues[outpoint] =
	vinput[3].get_int64() * SATOSHI;
	}
	}
	if (!fValid) {
	BOOST_ERROR("Bad test: " << strTest);
	continue;
	}

	std::string transaction = test[1].get_str();
	CDataStream stream(ParseHex(transaction), SER_NETWORK,
	PROTOCOL_VERSION);
	CTransaction tx(deserialize, stream);

	TxValidationState state;
	fValid = CheckRegularTransaction(tx, state) && state.IsValid();

	PrecomputedTransactionData txdata(tx);
	for (size_t i = 0; i < tx.vin.size() && fValid; i++) {
	if (!mapprevOutScriptPubKeys.count(tx.vin[i].prevout)) {
	BOOST_ERROR("Bad test: " << strTest);
	break;
	}

	Amount amount = Amount::zero();
	if (0 != mapprevOutValues.count(tx.vin[i].prevout)) {
	amount = mapprevOutValues[tx.vin[i].prevout];
	}

	uint32_t verify_flags = ParseScriptFlags(test[2].get_str());
	fValid = VerifyScript(
	tx.vin[i].scriptSig,
	mapprevOutScriptPubKeys[tx.vin[i].prevout], verify_flags,
	TransactionSignatureChecker(&tx, i, amount, txdata), &err);
	}
	BOOST_CHECK_MESSAGE(!fValid, strTest);
	BOOST_CHECK_MESSAGE(err != ScriptError::OK, ScriptErrorString(err));
	}
	}
	}

	BOOST_AUTO_TEST_CASE(basic_transaction_tests) {
	// Random real transaction
	// (e2769b09e784f32f62ef849763d4f45b98e07ba658647343b915ff832b110436)
	uint8_t ch[] = {
	0x01, 0x00, 0x00, 0x00, 0x01, 0x6b, 0xff, 0x7f, 0xcd, 0x4f, 0x85, 0x65,
	0xef, 0x40, 0x6d, 0xd5, 0xd6, 0x3d, 0x4f, 0xf9, 0x4f, 0x31, 0x8f, 0xe8,
	0x20, 0x27, 0xfd, 0x4d, 0xc4, 0x51, 0xb0, 0x44, 0x74, 0x01, 0x9f, 0x74,
	0xb4, 0x00, 0x00, 0x00, 0x00, 0x8c, 0x49, 0x30, 0x46, 0x02, 0x21, 0x00,
	0xda, 0x0d, 0xc6, 0xae, 0xce, 0xfe, 0x1e, 0x06, 0xef, 0xdf, 0x05, 0x77,
	0x37, 0x57, 0xde, 0xb1, 0x68, 0x82, 0x09, 0x30, 0xe3, 0xb0, 0xd0, 0x3f,
	0x46, 0xf5, 0xfc, 0xf1, 0x50, 0xbf, 0x99, 0x0c, 0x02, 0x21, 0x00, 0xd2,
	0x5b, 0x5c, 0x87, 0x04, 0x00, 0x76, 0xe4, 0xf2, 0x53, 0xf8, 0x26, 0x2e,
	0x76, 0x3e, 0x2d, 0xd5, 0x1e, 0x7f, 0xf0, 0xbe, 0x15, 0x77, 0x27, 0xc4,
	0xbc, 0x42, 0x80, 0x7f, 0x17, 0xbd, 0x39, 0x01, 0x41, 0x04, 0xe6, 0xc2,
	0x6e, 0xf6, 0x7d, 0xc6, 0x10, 0xd2, 0xcd, 0x19, 0x24, 0x84, 0x78, 0x9a,
	0x6c, 0xf9, 0xae, 0xa9, 0x93, 0x0b, 0x94, 0x4b, 0x7e, 0x2d, 0xb5, 0x34,
	0x2b, 0x9d, 0x9e, 0x5b, 0x9f, 0xf7, 0x9a, 0xff, 0x9a, 0x2e, 0xe1, 0x97,
	0x8d, 0xd7, 0xfd, 0x01, 0xdf, 0xc5, 0x22, 0xee, 0x02, 0x28, 0x3d, 0x3b,
	0x06, 0xa9, 0xd0, 0x3a, 0xcf, 0x80, 0x96, 0x96, 0x8d, 0x7d, 0xbb, 0x0f,
	0x91, 0x78, 0xff, 0xff, 0xff, 0xff, 0x02, 0x8b, 0xa7, 0x94, 0x0e, 0x00,
	0x00, 0x00, 0x00, 0x19, 0x76, 0xa9, 0x14, 0xba, 0xde, 0xec, 0xfd, 0xef,
	0x05, 0x07, 0x24, 0x7f, 0xc8, 0xf7, 0x42, 0x41, 0xd7, 0x3b, 0xc0, 0x39,
	0x97, 0x2d, 0x7b, 0x88, 0xac, 0x40, 0x94, 0xa8, 0x02, 0x00, 0x00, 0x00,
	0x00, 0x19, 0x76, 0xa9, 0x14, 0xc1, 0x09, 0x32, 0x48, 0x3f, 0xec, 0x93,
	0xed, 0x51, 0xf5, 0xfe, 0x95, 0xe7, 0x25, 0x59, 0xf2, 0xcc, 0x70, 0x43,
	0xf9, 0x88, 0xac, 0x00, 0x00, 0x00, 0x00, 0x00};
	std::vector<uint8_t> vch(ch, ch + sizeof(ch) - 1);
	CDataStream stream(vch, SER_DISK, CLIENT_VERSION);
	CMutableTransaction tx;
	stream >> tx;
	TxValidationState state;
	BOOST_CHECK_MESSAGE(CheckRegularTransaction(CTransaction(tx), state) &&
	state.IsValid(),
	"Simple deserialized transaction should be valid.");

	// Check that duplicate txins fail
	tx.vin.push_back(tx.vin[0]);
	BOOST_CHECK_MESSAGE(!CheckRegularTransaction(CTransaction(tx), state) \|\|
	!state.IsValid(),
	"Transaction with duplicate txins should be invalid.");
	}

	BOOST_AUTO_TEST_CASE(test_Get) {
	FillableSigningProvider keystore;
	CCoinsView coinsDummy;
	CCoinsViewCache coins(&coinsDummy);
	std::vector<CMutableTransaction> dummyTransactions = SetupDummyInputs(
	keystore, coins, {{11 * CENT, 50 * CENT, 21 * CENT, 22 * CENT}});

	CMutableTransaction t1;
	t1.vin.resize(3);
	t1.vin[0].prevout = COutPoint(dummyTransactions[0].GetId(), 1);
	t1.vin[0].scriptSig << std::vector<uint8_t>(65, 0);
	t1.vin[1].prevout = COutPoint(dummyTransactions[1].GetId(), 0);
	t1.vin[1].scriptSig << std::vector<uint8_t>(65, 0)
	<< std::vector<uint8_t>(33, 4);
	t1.vin[2].prevout = COutPoint(dummyTransactions[1].GetId(), 1);
	t1.vin[2].scriptSig << std::vector<uint8_t>(65, 0)
	<< std::vector<uint8_t>(33, 4);
	t1.vout.resize(2);
	t1.vout[0].nValue = 90 * CENT;
	t1.vout[0].scriptPubKey << OP_1;

	BOOST_CHECK(AreInputsStandard(CTransaction(t1), coins,
	STANDARD_SCRIPT_VERIFY_FLAGS));
	}

	static void CreateCreditAndSpend(const FillableSigningProvider &keystore,
	const CScript &outscript,
	CTransactionRef &output,
	CMutableTransaction &input,
	bool success = true) {
	CMutableTransaction outputm;
	outputm.nVersion = 1;
	outputm.vin.resize(1);
	outputm.vin[0].prevout = COutPoint();
	outputm.vin[0].scriptSig = CScript();
	outputm.vout.resize(1);
	outputm.vout[0].nValue = SATOSHI;
	outputm.vout[0].scriptPubKey = outscript;
	CDataStream ssout(SER_NETWORK, PROTOCOL_VERSION);
	ssout << outputm;
	ssout >> output;
	BOOST_CHECK_EQUAL(output->vin.size(), 1UL);
	BOOST_CHECK(output->vin[0] == outputm.vin[0]);
	BOOST_CHECK_EQUAL(output->vout.size(), 1UL);
	BOOST_CHECK(output->vout[0] == outputm.vout[0]);

	CMutableTransaction inputm;
	inputm.nVersion = 1;
	inputm.vin.resize(1);
	inputm.vin[0].prevout = COutPoint(output->GetId(), 0);
	inputm.vout.resize(1);
	inputm.vout[0].nValue = SATOSHI;
	inputm.vout[0].scriptPubKey = CScript();
	bool ret =
	SignSignature(keystore, *output, inputm, 0, SigHashType().withForkId());
	BOOST_CHECK_EQUAL(ret, success);
	CDataStream ssin(SER_NETWORK, PROTOCOL_VERSION);
	ssin << inputm;
	ssin >> input;
	BOOST_CHECK_EQUAL(input.vin.size(), 1UL);
	BOOST_CHECK(input.vin[0] == inputm.vin[0]);
	BOOST_CHECK_EQUAL(input.vout.size(), 1UL);
	BOOST_CHECK(input.vout[0] == inputm.vout[0]);
	}

	static void CheckWithFlag(const CTransactionRef &output,
	const CMutableTransaction &input, int flags,
	bool success) {
	ScriptError error;
	CTransaction inputi(input);
	bool ret = VerifyScript(
	inputi.vin[0].scriptSig, output->vout[0].scriptPubKey,
	flags \| SCRIPT_ENABLE_SIGHASH_FORKID,
	TransactionSignatureChecker(&inputi, 0, output->vout[0].nValue),
	&error);
	BOOST_CHECK_EQUAL(ret, success);
	}

	static CScript PushAll(const std::vector<valtype> &values) {
	CScript result;
	for (const valtype &v : values) {
	if (v.size() == 0) {
	result << OP_0;
	} else if (v.size() == 1 && v[0] >= 1 && v[0] <= 16) {
	result << CScript::EncodeOP_N(v[0]);
	} else {
	result << v;
	}
	}
	return result;
	}

	static void ReplaceRedeemScript(CScript &script, const CScript &redeemScript) {
	std::vector<valtype> stack;
	EvalScript(stack, script, SCRIPT_VERIFY_STRICTENC, BaseSignatureChecker());
	BOOST_CHECK(stack.size() > 0);
	stack.back() =
	std::vector<uint8_t>(redeemScript.begin(), redeemScript.end());
	script = PushAll(stack);
	}

	BOOST_AUTO_TEST_CASE(test_big_transaction) {
	CKey key;
	key.MakeNewKey(false);
	FillableSigningProvider keystore;
	BOOST_CHECK(keystore.AddKeyPubKey(key, key.GetPubKey()));
	CScript scriptPubKey = CScript()
	<< ToByteVector(key.GetPubKey()) << OP_CHECKSIG;

	std::vector<SigHashType> sigHashes;
	sigHashes.emplace_back(SIGHASH_NONE \| SIGHASH_FORKID);
	sigHashes.emplace_back(SIGHASH_SINGLE \| SIGHASH_FORKID);
	sigHashes.emplace_back(SIGHASH_ALL \| SIGHASH_FORKID);
	sigHashes.emplace_back(SIGHASH_NONE \| SIGHASH_FORKID \|
	SIGHASH_ANYONECANPAY);
	sigHashes.emplace_back(SIGHASH_SINGLE \| SIGHASH_FORKID \|
	SIGHASH_ANYONECANPAY);
	sigHashes.emplace_back(SIGHASH_ALL \| SIGHASH_FORKID \| SIGHASH_ANYONECANPAY);

	CMutableTransaction mtx;
	mtx.nVersion = 1;

	// create a big transaction of 4500 inputs signed by the same key.
	const static size_t OUTPUT_COUNT = 4500;
	mtx.vout.reserve(OUTPUT_COUNT);

	for (size_t ij = 0; ij < OUTPUT_COUNT; ij++) {
	size_t i = mtx.vin.size();
	TxId prevId(uint256S("0000000000000000000000000000000000000000000000000"
	"000000000000100"));
	COutPoint outpoint(prevId, i);

	mtx.vin.resize(mtx.vin.size() + 1);
	mtx.vin[i].prevout = outpoint;
	mtx.vin[i].scriptSig = CScript();

	mtx.vout.emplace_back(1000 * SATOSHI, CScript() << OP_1);
	}

	// sign all inputs
	for (size_t i = 0; i < mtx.vin.size(); i++) {
	bool hashSigned =
	SignSignature(keystore, scriptPubKey, mtx, i, 1000 * SATOSHI,
	sigHashes.at(i % sigHashes.size()));
	BOOST_CHECK_MESSAGE(hashSigned, "Failed to sign test transaction");
	}

	CTransaction tx(mtx);

	// check all inputs concurrently, with the cache
	PrecomputedTransactionData txdata(tx);
	- boost::thread_group threadGroup;
	CCheckQueue<CScriptCheck> scriptcheckqueue(128);
	CCheckQueueControl<CScriptCheck> control(&scriptcheckqueue);

	- for (int i = 0; i < 20; i++) {
	- threadGroup.create_thread(std::bind(&CCheckQueue<CScriptCheck>::Thread,
	- std::ref(scriptcheckqueue)));
	- }
	+ scriptcheckqueue.StartWorkerThreads(20);

	std::vector<Coin> coins;
	for (size_t i = 0; i < mtx.vin.size(); i++) {
	CTxOut out;
	out.nValue = 1000 * SATOSHI;
	out.scriptPubKey = scriptPubKey;
	coins.emplace_back(std::move(out), 1, false);
	}

	for (size_t i = 0; i < mtx.vin.size(); i++) {
	std::vector<CScriptCheck> vChecks;
	CScriptCheck check(coins[tx.vin[i].prevout.GetN()].GetTxOut(), tx, i,
	STANDARD_SCRIPT_VERIFY_FLAGS, false, txdata);
	vChecks.push_back(CScriptCheck());
	check.swap(vChecks.back());
	control.Add(vChecks);
	}

	bool controlCheck = control.Wait();
	BOOST_CHECK(controlCheck);
	-
	- threadGroup.interrupt_all();
	- threadGroup.join_all();
	+ scriptcheckqueue.StopWorkerThreads();
	}

	SignatureData CombineSignatures(const CMutableTransaction &input1,
	const CMutableTransaction &input2,
	const CTransactionRef tx) {
	SignatureData sigdata;
	sigdata = DataFromTransaction(input1, 0, tx->vout[0]);
	sigdata.MergeSignatureData(DataFromTransaction(input2, 0, tx->vout[0]));
	ProduceSignature(
	DUMMY_SIGNING_PROVIDER,
	MutableTransactionSignatureCreator(&input1, 0, tx->vout[0].nValue),
	tx->vout[0].scriptPubKey, sigdata);
	return sigdata;
	}

	BOOST_AUTO_TEST_CASE(test_witness) {
	FillableSigningProvider keystore, keystore2;
	CKey key1, key2, key3, key1L, key2L;
	CPubKey pubkey1, pubkey2, pubkey3, pubkey1L, pubkey2L;
	key1.MakeNewKey(true);
	key2.MakeNewKey(true);
	key3.MakeNewKey(true);
	key1L.MakeNewKey(false);
	key2L.MakeNewKey(false);
	pubkey1 = key1.GetPubKey();
	pubkey2 = key2.GetPubKey();
	pubkey3 = key3.GetPubKey();
	pubkey1L = key1L.GetPubKey();
	pubkey2L = key2L.GetPubKey();
	BOOST_CHECK(keystore.AddKeyPubKey(key1, pubkey1));
	BOOST_CHECK(keystore.AddKeyPubKey(key2, pubkey2));
	BOOST_CHECK(keystore.AddKeyPubKey(key1L, pubkey1L));
	BOOST_CHECK(keystore.AddKeyPubKey(key2L, pubkey2L));
	CScript scriptPubkey1, scriptPubkey2, scriptPubkey1L, scriptPubkey2L,
	scriptMulti;
	scriptPubkey1 << ToByteVector(pubkey1) << OP_CHECKSIG;
	scriptPubkey2 << ToByteVector(pubkey2) << OP_CHECKSIG;
	scriptPubkey1L << ToByteVector(pubkey1L) << OP_CHECKSIG;
	scriptPubkey2L << ToByteVector(pubkey2L) << OP_CHECKSIG;
	std::vector<CPubKey> oneandthree;
	oneandthree.push_back(pubkey1);
	oneandthree.push_back(pubkey3);
	scriptMulti = GetScriptForMultisig(2, oneandthree);
	BOOST_CHECK(keystore.AddCScript(scriptPubkey1));
	BOOST_CHECK(keystore.AddCScript(scriptPubkey2));
	BOOST_CHECK(keystore.AddCScript(scriptPubkey1L));
	BOOST_CHECK(keystore.AddCScript(scriptPubkey2L));
	BOOST_CHECK(keystore.AddCScript(scriptMulti));
	BOOST_CHECK(keystore2.AddCScript(scriptMulti));
	BOOST_CHECK(keystore2.AddKeyPubKey(key3, pubkey3));

	CTransactionRef output1, output2;
	CMutableTransaction input1, input2;

	// Normal pay-to-compressed-pubkey.
	CreateCreditAndSpend(keystore, scriptPubkey1, output1, input1);
	CreateCreditAndSpend(keystore, scriptPubkey2, output2, input2);
	CheckWithFlag(output1, input1, 0, true);
	CheckWithFlag(output1, input1, SCRIPT_VERIFY_P2SH, true);
	CheckWithFlag(output1, input1, STANDARD_SCRIPT_VERIFY_FLAGS, true);
	CheckWithFlag(output1, input2, 0, false);
	CheckWithFlag(output1, input2, SCRIPT_VERIFY_P2SH, false);
	CheckWithFlag(output1, input2, STANDARD_SCRIPT_VERIFY_FLAGS, false);

	// P2SH pay-to-compressed-pubkey.
	CreateCreditAndSpend(keystore,
	GetScriptForDestination(ScriptHash(scriptPubkey1)),
	output1, input1);
	CreateCreditAndSpend(keystore,
	GetScriptForDestination(ScriptHash(scriptPubkey2)),
	output2, input2);
	ReplaceRedeemScript(input2.vin[0].scriptSig, scriptPubkey1);
	CheckWithFlag(output1, input1, 0, true);
	CheckWithFlag(output1, input1, SCRIPT_VERIFY_P2SH, true);
	CheckWithFlag(output1, input1, STANDARD_SCRIPT_VERIFY_FLAGS, true);
	CheckWithFlag(output1, input2, 0, true);
	CheckWithFlag(output1, input2, SCRIPT_VERIFY_P2SH, false);
	CheckWithFlag(output1, input2, STANDARD_SCRIPT_VERIFY_FLAGS, false);

	// Normal pay-to-uncompressed-pubkey.
	CreateCreditAndSpend(keystore, scriptPubkey1L, output1, input1);
	CreateCreditAndSpend(keystore, scriptPubkey2L, output2, input2);
	CheckWithFlag(output1, input1, 0, true);
	CheckWithFlag(output1, input1, SCRIPT_VERIFY_P2SH, true);
	CheckWithFlag(output1, input1, STANDARD_SCRIPT_VERIFY_FLAGS, true);
	CheckWithFlag(output1, input2, 0, false);
	CheckWithFlag(output1, input2, SCRIPT_VERIFY_P2SH, false);
	CheckWithFlag(output1, input2, STANDARD_SCRIPT_VERIFY_FLAGS, false);

	// P2SH pay-to-uncompressed-pubkey.
	CreateCreditAndSpend(keystore,
	GetScriptForDestination(ScriptHash(scriptPubkey1L)),
	output1, input1);
	CreateCreditAndSpend(keystore,
	GetScriptForDestination(ScriptHash(scriptPubkey2L)),
	output2, input2);
	ReplaceRedeemScript(input2.vin[0].scriptSig, scriptPubkey1L);
	CheckWithFlag(output1, input1, 0, true);
	CheckWithFlag(output1, input1, SCRIPT_VERIFY_P2SH, true);
	CheckWithFlag(output1, input1, STANDARD_SCRIPT_VERIFY_FLAGS, true);
	CheckWithFlag(output1, input2, 0, true);
	CheckWithFlag(output1, input2, SCRIPT_VERIFY_P2SH, false);
	CheckWithFlag(output1, input2, STANDARD_SCRIPT_VERIFY_FLAGS, false);

	// Normal 2-of-2 multisig
	CreateCreditAndSpend(keystore, scriptMulti, output1, input1, false);
	CheckWithFlag(output1, input1, 0, false);
	CreateCreditAndSpend(keystore2, scriptMulti, output2, input2, false);
	CheckWithFlag(output2, input2, 0, false);
	BOOST_CHECK(output1 == output2);
	UpdateInput(input1.vin[0], CombineSignatures(input1, input2, output1));
	CheckWithFlag(output1, input1, STANDARD_SCRIPT_VERIFY_FLAGS, true);

	// P2SH 2-of-2 multisig
	CreateCreditAndSpend(keystore,
	GetScriptForDestination(ScriptHash(scriptMulti)),
	output1, input1, false);
	CheckWithFlag(output1, input1, 0, true);
	CheckWithFlag(output1, input1, SCRIPT_VERIFY_P2SH, false);
	CreateCreditAndSpend(keystore2,
	GetScriptForDestination(ScriptHash(scriptMulti)),
	output2, input2, false);
	CheckWithFlag(output2, input2, 0, true);
	CheckWithFlag(output2, input2, SCRIPT_VERIFY_P2SH, false);
	BOOST_CHECK(output1 == output2);
	UpdateInput(input1.vin[0], CombineSignatures(input1, input2, output1));
	CheckWithFlag(output1, input1, SCRIPT_VERIFY_P2SH, true);
	CheckWithFlag(output1, input1, STANDARD_SCRIPT_VERIFY_FLAGS, true);
	}

	BOOST_AUTO_TEST_CASE(test_IsStandard) {
	LOCK(cs_main);
	FillableSigningProvider keystore;
	CCoinsView coinsDummy;
	CCoinsViewCache coins(&coinsDummy);
	std::vector<CMutableTransaction> dummyTransactions = SetupDummyInputs(
	keystore, coins, {{11 * CENT, 50 * CENT, 21 * CENT, 22 * CENT}});

	CMutableTransaction t;
	t.vin.resize(1);
	t.vin[0].prevout = COutPoint(dummyTransactions[0].GetId(), 1);
	t.vin[0].scriptSig << std::vector<uint8_t>(65, 0);
	t.vout.resize(1);
	t.vout[0].nValue = 90 * CENT;
	CKey key;
	key.MakeNewKey(true);
	t.vout[0].scriptPubKey = GetScriptForDestination(PKHash(key.GetPubKey()));

	std::string reason;
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));

	// Check dust with default relay fee:
	Amount nDustThreshold = 3 * 182 * dustRelayFee.GetFeePerK() / 1000;
	BOOST_CHECK_EQUAL(nDustThreshold, 546 * SATOSHI);
	// dust:
	t.vout[0].nValue = nDustThreshold - SATOSHI;
	reason.clear();
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
	BOOST_CHECK_EQUAL(reason, "dust");
	// not dust:
	t.vout[0].nValue = nDustThreshold;
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));

	// Disallowed nVersion
	t.nVersion = -1;
	reason.clear();
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
	BOOST_CHECK_EQUAL(reason, "version");

	t.nVersion = 0;
	reason.clear();
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
	BOOST_CHECK_EQUAL(reason, "version");

	t.nVersion = 3;
	reason.clear();
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
	BOOST_CHECK_EQUAL(reason, "version");

	// Allowed nVersion
	t.nVersion = 1;
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));

	t.nVersion = 2;
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));

	// Check dust with odd relay fee to verify rounding:
	// nDustThreshold = 182 * 1234 / 1000 * 3
	dustRelayFee = CFeeRate(1234 * SATOSHI);
	// dust:
	t.vout[0].nValue = (672 - 1) * SATOSHI;
	reason.clear();
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
	BOOST_CHECK_EQUAL(reason, "dust");
	// not dust:
	t.vout[0].nValue = 672 * SATOSHI;
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));
	dustRelayFee = CFeeRate(DUST_RELAY_TX_FEE);

	t.vout[0].scriptPubKey = CScript() << OP_1;
	reason.clear();
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
	BOOST_CHECK_EQUAL(reason, "scriptpubkey");

	// MAX_OP_RETURN_RELAY-byte TxoutType::NULL_DATA (standard)
	t.vout[0].scriptPubKey =
	CScript() << OP_RETURN
	<< ParseHex("646578784062697477617463682e636f2092c558ed52c56d"
	"8dd14ca76226bc936a84820d898443873eb03d8854b21fa3"
	"952b99a2981873e74509281730d78a21786d34a38bd1ebab"
	"822fad42278f7f4420db6ab1fd2b6826148d4f73bb41ec2d"
	"40a6d5793d66e17074a0c56a8a7df21062308f483dd6e38d"
	"53609d350038df0a1b2a9ac8332016e0b904f66880dd0108"
	"81c4e8074cce8e4ad6c77cb3460e01bf0e7e811b5f945f83"
	"732ba6677520a893d75d9a966cb8f85dc301656b1635c631"
	"f5d00d4adf73f2dd112ca75cf19754651909becfbe65aed1"
	"3afb2ab8");
	BOOST_CHECK_EQUAL(MAX_OP_RETURN_RELAY, t.vout[0].scriptPubKey.size());
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));

	// MAX_OP_RETURN_RELAY+1-byte TxoutType::NULL_DATA (non-standard)
	t.vout[0].scriptPubKey =
	CScript() << OP_RETURN
	<< ParseHex("646578784062697477617463682e636f2092c558ed52c56d"
	"8dd14ca76226bc936a84820d898443873eb03d8854b21fa3"
	"952b99a2981873e74509281730d78a21786d34a38bd1ebab"
	"822fad42278f7f4420db6ab1fd2b6826148d4f73bb41ec2d"
	"40a6d5793d66e17074a0c56a8a7df21062308f483dd6e38d"
	"53609d350038df0a1b2a9ac8332016e0b904f66880dd0108"
	"81c4e8074cce8e4ad6c77cb3460e01bf0e7e811b5f945f83"
	"732ba6677520a893d75d9a966cb8f85dc301656b1635c631"
	"f5d00d4adf73f2dd112ca75cf19754651909becfbe65aed1"
	"3afb2ab800");
	BOOST_CHECK_EQUAL(MAX_OP_RETURN_RELAY + 1, t.vout[0].scriptPubKey.size());
	reason.clear();
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
	BOOST_CHECK_EQUAL(reason, "scriptpubkey");

	/**
	* Check when a custom value is used for -datacarriersize .
	*/
	unsigned newMaxSize = 90;
	gArgs.ForceSetArg("-datacarriersize", ToString(newMaxSize));

	// Max user provided payload size is standard
	t.vout[0].scriptPubKey =
	CScript() << OP_RETURN
	<< ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909"
	"a67962e0ea1f61deb649f6bc3f4cef3804678afdb0fe5548"
	"271967f1a67130b7105cd6a828e03909a67962e0ea1f61de"
	"b649f6bc3f4cef3877696e64657878");
	BOOST_CHECK_EQUAL(t.vout[0].scriptPubKey.size(), newMaxSize);
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));

	// Max user provided payload size + 1 is non-standard
	t.vout[0].scriptPubKey =
	CScript() << OP_RETURN
	<< ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909"
	"a67962e0ea1f61deb649f6bc3f4cef3804678afdb0fe5548"
	"271967f1a67130b7105cd6a828e03909a67962e0ea1f61de"
	"b649f6bc3f4cef3877696e6465787800");
	BOOST_CHECK_EQUAL(t.vout[0].scriptPubKey.size(), newMaxSize + 1);
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));

	// Clear custom confirguration.
	gArgs.ClearForcedArg("-datacarriersize");

	// Data payload can be encoded in any way...
	t.vout[0].scriptPubKey = CScript() << OP_RETURN << ParseHex("");
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));
	t.vout[0].scriptPubKey = CScript()
	<< OP_RETURN << ParseHex("00") << ParseHex("01");
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));
	// OP_RESERVED is considered to be a PUSHDATA type opcode by IsPushOnly()!
	t.vout[0].scriptPubKey = CScript() << OP_RETURN << OP_RESERVED << -1 << 0
	<< ParseHex("01") << 2 << 3 << 4 << 5
	<< 6 << 7 << 8 << 9 << 10 << 11 << 12
	<< 13 << 14 << 15 << 16;
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));
	t.vout[0].scriptPubKey = CScript()
	<< OP_RETURN << 0 << ParseHex("01") << 2
	<< ParseHex("fffffffffffffffffffffffffffffffffffff"
	"fffffffffffffffffffffffffffffffffff");
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));

	// ...so long as it only contains PUSHDATA's
	t.vout[0].scriptPubKey = CScript() << OP_RETURN << OP_RETURN;
	reason.clear();
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
	BOOST_CHECK_EQUAL(reason, "scriptpubkey");

	// TxoutType::NULL_DATA w/o PUSHDATA
	t.vout.resize(1);
	t.vout[0].scriptPubKey = CScript() << OP_RETURN;
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));

	// Only one TxoutType::NULL_DATA permitted in all cases
	t.vout.resize(2);
	t.vout[0].scriptPubKey =
	CScript() << OP_RETURN
	<< ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909"
	"a67962e0ea1f61deb649f6bc3f4cef38");
	t.vout[1].scriptPubKey =
	CScript() << OP_RETURN
	<< ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909"
	"a67962e0ea1f61deb649f6bc3f4cef38");
	reason.clear();
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
	BOOST_CHECK_EQUAL(reason, "multi-op-return");

	t.vout[0].scriptPubKey =
	CScript() << OP_RETURN
	<< ParseHex("04678afdb0fe5548271967f1a67130b7105cd6a828e03909"
	"a67962e0ea1f61deb649f6bc3f4cef38");
	t.vout[1].scriptPubKey = CScript() << OP_RETURN;
	reason.clear();
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
	BOOST_CHECK_EQUAL(reason, "multi-op-return");

	t.vout[0].scriptPubKey = CScript() << OP_RETURN;
	t.vout[1].scriptPubKey = CScript() << OP_RETURN;
	reason.clear();
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
	BOOST_CHECK_EQUAL(reason, "multi-op-return");

	// Check large scriptSig (non-standard if size is >1650 bytes)
	t.vout.resize(1);
	t.vout[0].nValue = MAX_MONEY;
	t.vout[0].scriptPubKey = GetScriptForDestination(PKHash(key.GetPubKey()));
	// OP_PUSHDATA2 with len (3 bytes) + data (1647 bytes) = 1650 bytes
	t.vin[0].scriptSig = CScript() << std::vector<uint8_t>(1647, 0); // 1650
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));

	t.vin[0].scriptSig = CScript() << std::vector<uint8_t>(1648, 0); // 1651
	reason.clear();
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
	BOOST_CHECK_EQUAL(reason, "scriptsig-size");

	// Check scriptSig format (non-standard if there are any other ops than just
	// PUSHs)
	t.vin[0].scriptSig = CScript()
	// OP_n (single byte pushes: n = 1, 0, -1, 16)
	<< OP_TRUE << OP_0 << OP_1NEGATE
	<< OP_16
	// OP_PUSHx [...x bytes...]
	<< std::vector<uint8_t>(75, 0)
	// OP_PUSHDATA1 x [...x bytes...]
	<< std::vector<uint8_t>(235, 0)
	// OP_PUSHDATA2 x [...x bytes...]
	<< std::vector<uint8_t>(1234, 0) << OP_9;
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));

	const std::vector<uint8_t> non_push_ops = {
	// arbitrary set of non-push operations
	OP_NOP,
	OP_VERIFY,
	OP_IF,
	OP_ROT,
	OP_3DUP,
	OP_SIZE,
	OP_EQUAL,
	OP_ADD,
	OP_SUB,
	OP_HASH256,
	OP_CODESEPARATOR,
	OP_CHECKSIG,
	OP_CHECKLOCKTIMEVERIFY};

	CScript::const_iterator pc = t.vin[0].scriptSig.begin();
	while (pc < t.vin[0].scriptSig.end()) {
	opcodetype opcode;
	CScript::const_iterator prev_pc = pc;
	// advance to next op
	t.vin[0].scriptSig.GetOp(pc, opcode);
	// for the sake of simplicity, we only replace single-byte push
	// operations
	if (opcode >= 1 && opcode <= OP_PUSHDATA4) {
	continue;
	}

	int index = prev_pc - t.vin[0].scriptSig.begin();
	// save op
	uint8_t orig_op = *prev_pc;
	// replace current push-op with each non-push-op
	for (auto op : non_push_ops) {
	t.vin[0].scriptSig[index] = op;
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
	BOOST_CHECK_EQUAL(reason, "scriptsig-not-pushonly");
	}
	// restore op
	t.vin[0].scriptSig[index] = orig_op;
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));
	}

	// Check bare multisig (standard if policy flag fIsBareMultisigStd is set)
	fIsBareMultisigStd = true;
	// simple 1-of-1
	t.vout[0].scriptPubKey = GetScriptForMultisig(1, {key.GetPubKey()});
	t.vin[0].scriptSig = CScript() << std::vector<uint8_t>(65, 0);
	BOOST_CHECK(IsStandardTx(CTransaction(t), reason));

	fIsBareMultisigStd = false;
	reason.clear();
	BOOST_CHECK(!IsStandardTx(CTransaction(t), reason));
	BOOST_CHECK_EQUAL(reason, "bare-multisig");
	fIsBareMultisigStd = DEFAULT_PERMIT_BAREMULTISIG;
	}

	BOOST_AUTO_TEST_CASE(txsize_activation_test) {
	const Config &config = GetConfig();
	const Consensus::Params &params = config.GetChainParams().GetConsensus();
	const int32_t magneticAnomalyActivationHeight =
	params.magneticAnomalyHeight;

	// A minimaly sized transction.
	CTransaction minTx;
	TxValidationState state;

	BOOST_CHECK(ContextualCheckTransaction(
	params, minTx, state, magneticAnomalyActivationHeight - 1, 5678, 1234));
	BOOST_CHECK(!ContextualCheckTransaction(
	params, minTx, state, magneticAnomalyActivationHeight, 5678, 1234));
	BOOST_CHECK_EQUAL(state.GetRejectReason(), "bad-txns-undersize");
	}

	BOOST_AUTO_TEST_CASE(tx_getvalueout) {
	CMutableTransaction mtx;

	// Negative output value
	mtx.vout.resize(1);
	mtx.vout[0].nValue = -1 * SATOSHI;
	CTransaction negative_tx{mtx};
	BOOST_CHECK_THROW(negative_tx.GetValueOut(), std::runtime_error);

	// Good output
	mtx.vout[0].nValue = 10000 * SATOSHI;
	CTransaction valid_one_output_tx{mtx};
	BOOST_CHECK_EQUAL(valid_one_output_tx.GetValueOut(), 10000 * SATOSHI);

	// Maximum output
	mtx.vout[0].nValue = MAX_MONEY;
	CTransaction max_one_output_tx{mtx};
	BOOST_CHECK_EQUAL(max_one_output_tx.GetValueOut(), MAX_MONEY);

	// Too high output
	mtx.vout[0].nValue = MAX_MONEY + 1 * SATOSHI;
	CTransaction too_high_tx{mtx};
	BOOST_CHECK_THROW(too_high_tx.GetValueOut(), std::runtime_error);

	// Valid sum
	mtx.vout.resize(2);
	mtx.vout[0].nValue = 42 * SATOSHI;
	mtx.vout[1].nValue = 1337 * SATOSHI;
	CTransaction valid_tx{mtx};
	BOOST_CHECK_EQUAL(valid_tx.GetValueOut(), 1379 * SATOSHI);

	// Maximum sum
	mtx.vout[0].nValue = MAX_MONEY - 1 * SATOSHI;
	mtx.vout[1].nValue = 1 * SATOSHI;
	CTransaction max_two_outputs_tx{mtx};
	BOOST_CHECK_EQUAL(max_two_outputs_tx.GetValueOut(), MAX_MONEY);

	// Too high sum
	mtx.vout[0].nValue = MAX_MONEY - 1 * SATOSHI;
	mtx.vout[1].nValue = 2 * SATOSHI;
	CTransaction too_high_sum_tx{mtx};
	BOOST_CHECK_THROW(too_high_sum_tx.GetValueOut(), std::runtime_error);

	// First output valid, but the second output would cause an int64 overflow.
	// This issue was encountered while fuzzing:
	// https://github.com/bitcoin/bitcoin/issues/18046
	mtx.vout[0].nValue = 2 * SATOSHI;
	mtx.vout[1].nValue = (std::numeric_limits<int64_t>::max() - 1) * SATOSHI;
	CTransaction overflow_sum_tx{mtx};
	BOOST_CHECK_THROW(overflow_sum_tx.GetValueOut(), std::runtime_error);
	}

	BOOST_AUTO_TEST_SUITE_END()
	diff --git a/src/test/util/setup_common.cpp b/src/test/util/setup_common.cpp
	index 10fdd5af8..2e451fae6 100644
	--- a/src/test/util/setup_common.cpp
	+++ b/src/test/util/setup_common.cpp
	@@ -1,410 +1,409 @@
	// Copyright (c) 2011-2019 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 <test/util/setup_common.h>

	#include <banman.h>
	#include <chainparams.h>
	#include <config.h>
	#include <consensus/consensus.h>
	#include <consensus/validation.h>
	#include <crypto/sha256.h>
	#include <init.h>
	#include <interfaces/chain.h>
	#include <logging.h>
	#include <miner.h>
	#include <net.h>
	#include <net_processing.h>
	#include <noui.h>
	#include <pow/pow.h>
	#include <rpc/blockchain.h>
	#include <rpc/register.h>
	#include <rpc/server.h>
	#include <scheduler.h>
	#include <script/script_error.h>
	#include <script/scriptcache.h>
	#include <script/sigcache.h>
	#include <streams.h>
	#include <txdb.h>
	#include <txmempool.h>
	#include <util/strencodings.h>
	#include <util/time.h>
	#include <util/translation.h>
	#include <util/vector.h>
	#include <validation.h>
	#include <validationinterface.h>
	#include <walletinitinterface.h>

	#include <functional>
	#include <memory>

	const std::function<std::string(const char *)> G_TRANSLATION_FUN = nullptr;

	FastRandomContext g_insecure_rand_ctx;
	/**
	* Random context to get unique temp data dirs. Separate from
	* g_insecure_rand_ctx, which can be seeded from a const env var
	*/
	static FastRandomContext g_insecure_rand_ctx_temp_path;

	/**
	* Return the unsigned from the environment var if available,
	* otherwise 0
	*/
	static uint256 GetUintFromEnv(const std::string &env_name) {
	const char *num = std::getenv(env_name.c_str());
	if (!num) {
	return {};
	}
	return uint256S(num);
	}

	void Seed(FastRandomContext &ctx) {
	// Should be enough to get the seed once for the process
	static uint256 seed{};
	static const std::string RANDOM_CTX_SEED{"RANDOM_CTX_SEED"};
	if (seed.IsNull()) {
	seed = GetUintFromEnv(RANDOM_CTX_SEED);
	}
	if (seed.IsNull()) {
	seed = GetRandHash();
	}
	LogPrintf("%s: Setting random seed for current tests to %s=%s\n", __func__,
	RANDOM_CTX_SEED, seed.GetHex());
	ctx = FastRandomContext(seed);
	}

	std::ostream &operator<<(std::ostream &os, const uint256 &num) {
	os << num.ToString();
	return os;
	}

	std::ostream &operator<<(std::ostream &os, const ScriptError &err) {
	os << ScriptErrorString(err);
	return os;
	}

	std::vector<const char *> fixture_extra_args{};

	BasicTestingSetup::BasicTestingSetup(
	const std::string &chainName, const std::vector<const char *> &extra_args)
	: m_path_root{fs::temp_directory_path() / "test_common_" PACKAGE_NAME /
	g_insecure_rand_ctx_temp_path.rand256().ToString()},
	m_args{} {
	// clang-format off
	std::vector<const char *> arguments = Cat(
	{
	"dummy",
	"-printtoconsole=0",
	"-logsourcelocations",
	"-logtimemicros",
	"-debug",
	"-debugexclude=libevent",
	"-debugexclude=leveldb",
	},
	extra_args);
	// clang-format on
	arguments = Cat(arguments, fixture_extra_args);
	auto &config = const_cast<Config &>(GetConfig());
	SetMockTime(0);
	fs::create_directories(m_path_root);
	m_args.ForceSetArg("-datadir", fs::PathToString(m_path_root));
	gArgs.ForceSetArg("-datadir", fs::PathToString(m_path_root));
	gArgs.ClearPathCache();
	{
	SetupServerArgs(m_node);
	std::string error;
	const bool success{m_node.args->ParseParameters(
	arguments.size(), arguments.data(), error)};
	assert(success);
	assert(error.empty());
	}
	SelectParams(chainName);
	SeedInsecureRand();
	InitLogging(*m_node.args);
	AppInitParameterInteraction(config, *m_node.args);
	LogInstance().StartLogging();
	SHA256AutoDetect();
	ECC_Start();
	SetupEnvironment();
	SetupNetworking();
	InitSignatureCache();
	InitScriptExecutionCache();

	m_node.chain = interfaces::MakeChain(m_node, config.GetChainParams());
	g_wallet_init_interface.Construct(m_node);

	fCheckBlockIndex = true;
	static bool noui_connected = false;
	if (!noui_connected) {
	noui_connect();
	noui_connected = true;
	}
	}

	BasicTestingSetup::~BasicTestingSetup() {
	LogInstance().DisconnectTestLogger();
	fs::remove_all(m_path_root);
	gArgs.ClearArgs();
	ECC_Stop();
	}

	TestingSetup::TestingSetup(const std::string &chainName,
	const std::vector<const char *> &extra_args)
	: BasicTestingSetup(chainName, extra_args) {
	const Config &config = GetConfig();
	const CChainParams &chainparams = config.GetChainParams();

	// Ideally we'd move all the RPC tests to the functional testing framework
	// instead of unit tests, but for now we need these here.
	RPCServer rpcServer;
	RegisterAllRPCCommands(config, rpcServer, tableRPC);

	/**
	* RPC does not come out of the warmup state on its own. Normally, this is
	* handled in bitcoind's init path, but unit tests do not trigger this
	* codepath, so we call it explicitly as part of setup.
	*/
	std::string rpcWarmupStatus;
	if (RPCIsInWarmup(&rpcWarmupStatus)) {
	SetRPCWarmupFinished();
	}

	m_node.scheduler = std::make_unique<CScheduler>();

	// We have to run a scheduler thread to prevent ActivateBestChain
	// from blocking due to queue overrun.
	threadGroup.create_thread([&] { m_node.scheduler->serviceQueue(); });
	GetMainSignals().RegisterBackgroundSignalScheduler(*m_node.scheduler);

	pblocktree.reset(new CBlockTreeDB(1 << 20, true));

	m_node.mempool = std::make_unique<CTxMemPool>(1);

	m_node.chainman = &::g_chainman;
	m_node.chainman->InitializeChainstate(*m_node.mempool);
	::ChainstateActive().InitCoinsDB(
	/* cache_size_bytes / 1 << 23, / in_memory */ true,
	/* should_wipe */ false);
	assert(!::ChainstateActive().CanFlushToDisk());
	::ChainstateActive().InitCoinsCache(1 << 23);
	assert(::ChainstateActive().CanFlushToDisk());
	if (!LoadGenesisBlock(chainparams)) {
	throw std::runtime_error("LoadGenesisBlock failed.");
	}
	{
	BlockValidationState state;
	if (!ActivateBestChain(config, state)) {
	throw std::runtime_error(
	strprintf("ActivateBestChain failed. (%s)", state.ToString()));
	}
	}
	constexpr int script_check_threads = 2;
	- for (int i = 0; i < script_check_threads; ++i) {
	- threadGroup.create_thread([i]() { return ThreadScriptCheck(i); });
	- }
	+ StartScriptCheckWorkerThreads(script_check_threads);

	m_node.banman = std::make_unique<BanMan>(
	m_args.GetDataDirPath() / "banlist.dat", chainparams, nullptr,
	DEFAULT_MISBEHAVING_BANTIME);
	// Deterministic randomness for tests.
	m_node.connman = std::make_unique<CConnman>(config, 0x1337, 0x1337);
	m_node.peerman = PeerManager::make(
	chainparams, m_node.connman, m_node.banman.get(), m_node.scheduler,
	m_node.chainman, m_node.mempool, false);
	{
	CConnman::Options options;
	options.m_msgproc = m_node.peerman.get();
	m_node.connman->Init(options);
	}
	}

	TestingSetup::~TestingSetup() {
	if (m_node.scheduler) {
	m_node.scheduler->stop();
	}
	threadGroup.interrupt_all();
	threadGroup.join_all();
	+ StopScriptCheckWorkerThreads();
	GetMainSignals().FlushBackgroundCallbacks();
	GetMainSignals().UnregisterBackgroundSignalScheduler();
	m_node.connman.reset();
	m_node.banman.reset();
	m_node.args = nullptr;
	UnloadBlockIndex(m_node.mempool.get(), *m_node.chainman);
	m_node.mempool.reset();
	m_node.scheduler.reset();
	m_node.chainman->Reset();
	m_node.chainman = nullptr;
	pblocktree.reset();
	}

	TestChain100Setup::TestChain100Setup() {
	// Generate a 100-block chain:
	coinbaseKey.MakeNewKey(true);
	CScript scriptPubKey = CScript() << ToByteVector(coinbaseKey.GetPubKey())
	<< OP_CHECKSIG;
	for (int i = 0; i < COINBASE_MATURITY; i++) {
	std::vector<CMutableTransaction> noTxns;
	CBlock b = CreateAndProcessBlock(noTxns, scriptPubKey);
	m_coinbase_txns.push_back(b.vtx[0]);
	}
	}

	CBlock TestChain100Setup::CreateAndProcessBlock(
	const std::vector<CMutableTransaction> &txns, const CScript &scriptPubKey) {
	const Config &config = GetConfig();
	CTxMemPool empty_pool;
	CBlock block =
	BlockAssembler(config, empty_pool).CreateNewBlock(scriptPubKey)->block;

	Assert(block.vtx.size() == 1);
	for (const CMutableTransaction &tx : txns) {
	block.vtx.push_back(MakeTransactionRef(tx));
	}

	// Order transactions by canonical order
	std::sort(std::begin(block.vtx) + 1, std::end(block.vtx),
	[](const std::shared_ptr<const CTransaction> &txa,
	const std::shared_ptr<const CTransaction> &txb) -> bool {
	return txa->GetId() < txb->GetId();
	});

	// IncrementExtraNonce creates a valid coinbase and merkleRoot
	{
	LOCK(cs_main);
	unsigned int extraNonce = 0;
	IncrementExtraNonce(&block, ::ChainActive().Tip(),
	config.GetMaxBlockSize(), extraNonce);
	}

	const Consensus::Params &params = config.GetChainParams().GetConsensus();
	while (!CheckProofOfWork(block.GetHash(), block.nBits, params)) {
	++block.nNonce;
	}

	std::shared_ptr<const CBlock> shared_pblock =
	std::make_shared<const CBlock>(block);
	Assert(m_node.chainman)
	->ProcessNewBlock(config, shared_pblock, true, nullptr);

	return block;
	}

	TestChain100Setup::~TestChain100Setup() {}

	CTxMemPoolEntry TestMemPoolEntryHelper::FromTx(const CMutableTransaction &tx) {
	return FromTx(MakeTransactionRef(tx));
	}

	CTxMemPoolEntry TestMemPoolEntryHelper::FromTx(const CTransactionRef &tx) {
	return CTxMemPoolEntry(tx, nFee, nTime, nHeight, spendsCoinbase,
	nSigOpCount, LockPoints());
	}

	/**
	* @returns a real block
	* (0000000000013b8ab2cd513b0261a14096412195a72a0c4827d229dcc7e0f7af) with 9
	* txs.
	*/
	CBlock getBlock13b8a() {
	CBlock block;
	CDataStream stream(
	ParseHex(
	"0100000090f0a9f110702f808219ebea1173056042a714bad51b916cb680000000"
	"0000005275289558f51c9966699404ae2294730c3c9f9bda53523ce50e9b95e558"
	"da2fdb261b4d4c86041b1ab1bf9309010000000100000000000000000000000000"
	"00000000000000000000000000000000000000ffffffff07044c86041b0146ffff"
	"ffff0100f2052a01000000434104e18f7afbe4721580e81e8414fc8c24d7cfacf2"
	"54bb5c7b949450c3e997c2dc1242487a8169507b631eb3771f2b425483fb13102c"
	"4eb5d858eef260fe70fbfae0ac00000000010000000196608ccbafa16abada9027"
	"80da4dc35dafd7af05fa0da08cf833575f8cf9e836000000004a493046022100da"
	"b24889213caf43ae6adc41cf1c9396c08240c199f5225acf45416330fd7dbd0221"
	"00fe37900e0644bf574493a07fc5edba06dbc07c311b947520c2d514bc5725dcb4"
	"01ffffffff0100f2052a010000001976a914f15d1921f52e4007b146dfa60f369e"
	"d2fc393ce288ac000000000100000001fb766c1288458c2bafcfec81e48b24d98e"
	"c706de6b8af7c4e3c29419bfacb56d000000008c493046022100f268ba165ce0ad"
	"2e6d93f089cfcd3785de5c963bb5ea6b8c1b23f1ce3e517b9f022100da7c0f21ad"
	"c6c401887f2bfd1922f11d76159cbc597fbd756a23dcbb00f4d7290141042b4e86"
	"25a96127826915a5b109852636ad0da753c9e1d5606a50480cd0c40f1f8b8d8982"
	"35e571fe9357d9ec842bc4bba1827daaf4de06d71844d0057707966affffffff02"
	"80969800000000001976a9146963907531db72d0ed1a0cfb471ccb63923446f388"
	"ac80d6e34c000000001976a914f0688ba1c0d1ce182c7af6741e02658c7d4dfcd3"
	"88ac000000000100000002c40297f730dd7b5a99567eb8d27b78758f607507c522"
	"92d02d4031895b52f2ff010000008b483045022100f7edfd4b0aac404e5bab4fd3"
	"889e0c6c41aa8d0e6fa122316f68eddd0a65013902205b09cc8b2d56e1cd1f7f2f"
	"afd60a129ed94504c4ac7bdc67b56fe67512658b3e014104732012cb962afa90d3"
	"1b25d8fb0e32c94e513ab7a17805c14ca4c3423e18b4fb5d0e676841733cb83aba"
	"f975845c9f6f2a8097b7d04f4908b18368d6fc2d68ecffffffffca5065ff9617cb"
	"cba45eb23726df6498a9b9cafed4f54cbab9d227b0035ddefb000000008a473044"
	"022068010362a13c7f9919fa832b2dee4e788f61f6f5d344a7c2a0da6ae7406056"
	"58022006d1af525b9a14a35c003b78b72bd59738cd676f845d1ff3fc25049e0100"
	"3614014104732012cb962afa90d31b25d8fb0e32c94e513ab7a17805c14ca4c342"
	"3e18b4fb5d0e676841733cb83abaf975845c9f6f2a8097b7d04f4908b18368d6fc"
	"2d68ecffffffff01001ec4110200000043410469ab4181eceb28985b9b4e895c13"
	"fa5e68d85761b7eee311db5addef76fa8621865134a221bd01f28ec9999ee3e021"
	"e60766e9d1f3458c115fb28650605f11c9ac000000000100000001cdaf2f758e91"
	"c514655e2dc50633d1e4c84989f8aa90a0dbc883f0d23ed5c2fa010000008b4830"
	"4502207ab51be6f12a1962ba0aaaf24a20e0b69b27a94fac5adf45aa7d2d18ffd9"
	"236102210086ae728b370e5329eead9accd880d0cb070aea0c96255fae6c4f1ddc"
	"ce1fd56e014104462e76fd4067b3a0aa42070082dcb0bf2f388b6495cf33d78990"
	"4f07d0f55c40fbd4b82963c69b3dc31895d0c772c812b1d5fbcade15312ef1c0e8"
	"ebbb12dcd4ffffffff02404b4c00000000001976a9142b6ba7c9d796b75eef7942"
	"fc9288edd37c32f5c388ac002d3101000000001976a9141befba0cdc1ad5652937"
	"1864d9f6cb042faa06b588ac000000000100000001b4a47603e71b61bc3326efd9"
	"0111bf02d2f549b067f4c4a8fa183b57a0f800cb010000008a4730440220177c37"
	"f9a505c3f1a1f0ce2da777c339bd8339ffa02c7cb41f0a5804f473c9230220585b"
	"25a2ee80eb59292e52b987dad92acb0c64eced92ed9ee105ad153cdb12d0014104"
	"43bd44f683467e549dae7d20d1d79cbdb6df985c6e9c029c8d0c6cb46cc1a4d3cf"
	"7923c5021b27f7a0b562ada113bc85d5fda5a1b41e87fe6e8802817cf69996ffff"
	"ffff0280651406000000001976a9145505614859643ab7b547cd7f1f5e7e2a1232"
	"2d3788ac00aa0271000000001976a914ea4720a7a52fc166c55ff2298e07baf70a"
	"e67e1b88ac00000000010000000586c62cd602d219bb60edb14a3e204de0705176"
	"f9022fe49a538054fb14abb49e010000008c493046022100f2bc2aba2534becbdf"
	"062eb993853a42bbbc282083d0daf9b4b585bd401aa8c9022100b1d7fd7ee0b956"
	"00db8535bbf331b19eed8d961f7a8e54159c53675d5f69df8c014104462e76fd40"
	"67b3a0aa42070082dcb0bf2f388b6495cf33d789904f07d0f55c40fbd4b82963c6"
	"9b3dc31895d0c772c812b1d5fbcade15312ef1c0e8ebbb12dcd4ffffffff03ad0e"
	"58ccdac3df9dc28a218bcf6f1997b0a93306faaa4b3a28ae83447b217901000000"
	"8b483045022100be12b2937179da88599e27bb31c3525097a07cdb52422d165b3c"
	"a2f2020ffcf702200971b51f853a53d644ebae9ec8f3512e442b1bcb6c315a5b49"
	"1d119d10624c83014104462e76fd4067b3a0aa42070082dcb0bf2f388b6495cf33"
	"d789904f07d0f55c40fbd4b82963c69b3dc31895d0c772c812b1d5fbcade15312e"
	"f1c0e8ebbb12dcd4ffffffff2acfcab629bbc8685792603762c921580030ba144a"
	"f553d271716a95089e107b010000008b483045022100fa579a840ac258871365dd"
	"48cd7552f96c8eea69bd00d84f05b283a0dab311e102207e3c0ee9234814cfbb1b"
	"659b83671618f45abc1326b9edcc77d552a4f2a805c0014104462e76fd4067b3a0"
	"aa42070082dcb0bf2f388b6495cf33d789904f07d0f55c40fbd4b82963c69b3dc3"
	"1895d0c772c812b1d5fbcade15312ef1c0e8ebbb12dcd4ffffffffdcdc6023bbc9"
	"944a658ddc588e61eacb737ddf0a3cd24f113b5a8634c517fcd2000000008b4830"
	"450221008d6df731df5d32267954bd7d2dda2302b74c6c2a6aa5c0ca64ecbabc1a"
	"f03c75022010e55c571d65da7701ae2da1956c442df81bbf076cdbac25133f99d9"
	"8a9ed34c014104462e76fd4067b3a0aa42070082dcb0bf2f388b6495cf33d78990"
	"4f07d0f55c40fbd4b82963c69b3dc31895d0c772c812b1d5fbcade15312ef1c0e8"
	"ebbb12dcd4ffffffffe15557cd5ce258f479dfd6dc6514edf6d7ed5b21fcfa4a03"
	"8fd69f06b83ac76e010000008b483045022023b3e0ab071eb11de2eb1cc3a67261"
	"b866f86bf6867d4558165f7c8c8aca2d86022100dc6e1f53a91de3efe8f6351285"
	"0811f26284b62f850c70ca73ed5de8771fb451014104462e76fd4067b3a0aa4207"
	"0082dcb0bf2f388b6495cf33d789904f07d0f55c40fbd4b82963c69b3dc31895d0"
	"c772c812b1d5fbcade15312ef1c0e8ebbb12dcd4ffffffff01404b4c0000000000"
	"1976a9142b6ba7c9d796b75eef7942fc9288edd37c32f5c388ac00000000010000"
	"000166d7577163c932b4f9690ca6a80b6e4eb001f0a2fa9023df5595602aae96ed"
	"8d000000008a4730440220262b42546302dfb654a229cefc86432b89628ff259dc"
	"87edd1154535b16a67e102207b4634c020a97c3e7bbd0d4d19da6aa2269ad9dded"
	"4026e896b213d73ca4b63f014104979b82d02226b3a4597523845754d44f13639e"
	"3bf2df5e82c6aab2bdc79687368b01b1ab8b19875ae3c90d661a3d0a33161dab29"
	"934edeb36aa01976be3baf8affffffff02404b4c00000000001976a9144854e695"
	"a02af0aeacb823ccbc272134561e0a1688ac40420f00000000001976a914abee93"
	"376d6b37b5c2940655a6fcaf1c8e74237988ac0000000001000000014e3f8ef2e9"
	"1349a9059cb4f01e54ab2597c1387161d3da89919f7ea6acdbb371010000008c49"
	"304602210081f3183471a5ca22307c0800226f3ef9c353069e0773ac76bb580654"
	"d56aa523022100d4c56465bdc069060846f4fbf2f6b20520b2a80b08b168b31e66"
	"ddb9c694e240014104976c79848e18251612f8940875b2b08d06e6dc73b9840e88"
	"60c066b7e87432c477e9a59a453e71e6d76d5fe34058b800a098fc1740ce3012e8"
	"fc8a00c96af966ffffffff02c0e1e400000000001976a9144134e75a6fcb604203"
	"4aab5e18570cf1f844f54788ac404b4c00000000001976a9142b6ba7c9d796b75e"
	"ef7942fc9288edd37c32f5c388ac00000000"),
	SER_NETWORK, PROTOCOL_VERSION);
	stream >> block;
	return block;
	}
	diff --git a/src/validation.cpp b/src/validation.cpp
	index 3a8ede489..4c38ba31f 100644
	--- a/src/validation.cpp
	+++ b/src/validation.cpp
	@@ -1,6121 +1,6124 @@
	// Copyright (c) 2009-2010 Satoshi Nakamoto
	// Copyright (c) 2009-2018 The Bitcoin Core developers
	// Copyright (c) 2017-2020 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 <avalanche/avalanche.h>
	#include <avalanche/processor.h>
	#include <blockdb.h>
	#include <blockvalidity.h>
	#include <chainparams.h>
	#include <checkpoints.h>
	#include <checkqueue.h>
	#include <config.h>
	#include <consensus/activation.h>
	#include <consensus/merkle.h>
	#include <consensus/tx_check.h>
	#include <consensus/tx_verify.h>
	#include <consensus/validation.h>
	#include <hash.h>
	#include <index/txindex.h>
	#include <logging.h>
	#include <logging/timer.h>
	#include <minerfund.h>
	#include <node/ui_interface.h>
	#include <policy/fees.h>
	#include <policy/mempool.h>
	#include <policy/policy.h>
	#include <policy/settings.h>
	#include <pow/aserti32d.h> // For ResetASERTAnchorBlockCache
	#include <pow/pow.h>
	#include <primitives/block.h>
	#include <primitives/transaction.h>
	#include <random.h>
	#include <reverse_iterator.h>
	#include <script/script.h>
	#include <script/scriptcache.h>
	#include <script/sigcache.h>
	#include <shutdown.h>
	#include <timedata.h>
	#include <tinyformat.h>
	#include <txdb.h>
	#include <txmempool.h>
	#include <undo.h>
	#include <util/check.h> // For NDEBUG compile time check
	#include <util/moneystr.h>
	#include <util/strencodings.h>
	#include <util/system.h>
	#include <util/translation.h>
	#include <validationinterface.h>
	#include <warnings.h>

	#include <boost/algorithm/string/replace.hpp>

	#include <optional>
	#include <string>
	#include <thread>

	#define MICRO 0.000001
	#define MILLI 0.001

	/** Time to wait between writing blocks/block index to disk. */
	static constexpr std::chrono::hours DATABASE_WRITE_INTERVAL{1};
	/** Time to wait between flushing chainstate to disk. */
	static constexpr std::chrono::hours DATABASE_FLUSH_INTERVAL{24};
	const std::vector<std::string> CHECKLEVEL_DOC{
	"level 0 reads the blocks from disk",
	"level 1 verifies block validity",
	"level 2 verifies undo data",
	"level 3 checks disconnection of tip blocks",
	"level 4 tries to reconnect the blocks",
	"each level includes the checks of the previous levels",
	};

	ChainstateManager g_chainman;

	CChainState &ChainstateActive() {
	LOCK(::cs_main);
	assert(g_chainman.m_active_chainstate);
	return *g_chainman.m_active_chainstate;
	}

	CChain &ChainActive() {
	LOCK(::cs_main);
	return ::ChainstateActive().m_chain;
	}

	/**
	* Global state
	*
	* Mutex to guard access to validation specific variables, such as reading
	* or changing the chainstate.
	*
	* This may also need to be locked when updating the transaction pool, e.g. on
	* AcceptToMemoryPool. See CTxMemPool::cs comment for details.
	*
	* The transaction pool has a separate lock to allow reading from it and the
	* chainstate at the same time.
	*/
	RecursiveMutex cs_main;

	CBlockIndex *pindexBestHeader = nullptr;
	Mutex g_best_block_mutex;
	std::condition_variable g_best_block_cv;
	uint256 g_best_block;
	std::atomic_bool fImporting(false);
	std::atomic_bool fReindex(false);
	bool fHavePruned = false;
	bool fPruneMode = false;
	bool fRequireStandard = true;
	bool fCheckBlockIndex = false;
	bool fCheckpointsEnabled = DEFAULT_CHECKPOINTS_ENABLED;
	uint64_t nPruneTarget = 0;
	int64_t nMaxTipAge = DEFAULT_MAX_TIP_AGE;

	BlockHash hashAssumeValid;
	arith_uint256 nMinimumChainWork;

	CFeeRate minRelayTxFee = CFeeRate(DEFAULT_MIN_RELAY_TX_FEE_PER_KB);

	// Internal stuff
	namespace {
	CBlockIndex *pindexBestInvalid = nullptr;
	CBlockIndex *pindexBestParked = nullptr;

	RecursiveMutex 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;

	/** Dirty block index entries. */
	std::set<const CBlockIndex *> setDirtyBlockIndex;

	/** Dirty block file entries. */
	std::set<int> setDirtyFileInfo;
	} // namespace

	BlockValidationOptions::BlockValidationOptions(const Config &config)
	: excessiveBlockSize(config.GetMaxBlockSize()), checkPoW(true),
	checkMerkleRoot(true) {}

	CBlockIndex *LookupBlockIndex(const BlockHash &hash) {
	AssertLockHeld(cs_main);
	BlockMap::const_iterator it = g_chainman.BlockIndex().find(hash);
	return it == g_chainman.BlockIndex().end() ? nullptr : it->second;
	}

	CBlockIndex *FindForkInGlobalIndex(const CChain &chain,
	const CBlockLocator &locator) {
	AssertLockHeld(cs_main);

	// Find the latest block common to locator and chain - we expect that
	// locator.vHave is sorted descending by height.
	for (const BlockHash &hash : locator.vHave) {
	CBlockIndex *pindex = LookupBlockIndex(hash);
	if (pindex) {
	if (chain.Contains(pindex)) {
	return pindex;
	}
	if (pindex->GetAncestor(chain.Height()) == chain.Tip()) {
	return chain.Tip();
	}
	}
	}
	return chain.Genesis();
	}

	std::unique_ptr<CBlockTreeDB> pblocktree;

	static uint32_t GetNextBlockScriptFlags(const Consensus::Params &params,
	const CBlockIndex *pindex);

	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 CTxMemPool &pool, const CTransaction &tx,
	int flags, LockPoints *lp, bool useExistingLockPoints) {
	AssertLockHeld(cs_main);
	AssertLockHeld(pool.cs);

	CBlockIndex *tip = ::ChainActive().Tip();
	assert(tip != nullptr);

	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 {
	// CoinsTip() contains the UTXO set for ::ChainActive().Tip()
	CCoinsViewMemPool viewMemPool(&::ChainstateActive().CoinsTip(), pool);
	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];
	Coin coin;
	if (!viewMemPool.GetCoin(txin.prevout, coin)) {
	return error("%s: Missing input", __func__);
	}
	if (coin.GetHeight() == MEMPOOL_HEIGHT) {
	// Assume all mempool transaction confirm in the next block
	prevheights[txinIndex] = tip->nHeight + 1;
	} else {
	prevheights[txinIndex] = coin.GetHeight();
	}
	}
	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 (const 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);
	}

	// Command-line argument "-replayprotectionactivationtime=<timestamp>" will
	// cause the node to switch to replay protected SigHash ForkID value when the
	// median timestamp of the previous 11 blocks is greater than or equal to
	// <timestamp>. Defaults to the pre-defined timestamp when not set.
	static bool IsReplayProtectionEnabled(const Consensus::Params &params,
	int64_t nMedianTimePast) {
	return nMedianTimePast >= gArgs.GetArg("-replayprotectionactivationtime",
	params.gluonActivationTime);
	}

	static bool IsReplayProtectionEnabled(const Consensus::Params &params,
	const CBlockIndex *pindexPrev) {
	if (pindexPrev == nullptr) {
	return false;
	}

	return IsReplayProtectionEnabled(params, pindexPrev->GetMedianTimePast());
	}

	// Used to avoid mempool polluting consensus critical paths if CCoinsViewMempool
	// were somehow broken and returning the wrong scriptPubKeys
	static bool CheckInputsFromMempoolAndCache(
	const CTransaction &tx, TxValidationState &state,
	const CCoinsViewCache &view, const CTxMemPool &pool, const uint32_t flags,
	PrecomputedTransactionData &txdata, int &nSigChecksOut)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
	AssertLockHeld(cs_main);

	// pool.cs should be locked already, but go ahead and re-take the lock here
	// to enforce that mempool doesn't change between when we check the view and
	// when we actually call through to CheckInputScripts
	LOCK(pool.cs);

	assert(!tx.IsCoinBase());
	for (const CTxIn &txin : tx.vin) {
	const Coin &coin = view.AccessCoin(txin.prevout);

	// AcceptToMemoryPoolWorker has already checked that the coins are
	// available, so this shouldn't fail. If the inputs are not available
	// here then return false.
	if (coin.IsSpent()) {
	return false;
	}

	// Check equivalence for available inputs.
	const CTransactionRef &txFrom = pool.get(txin.prevout.GetTxId());
	if (txFrom) {
	assert(txFrom->GetId() == txin.prevout.GetTxId());
	assert(txFrom->vout.size() > txin.prevout.GetN());
	assert(txFrom->vout[txin.prevout.GetN()] == coin.GetTxOut());
	} else {
	const Coin &coinFromDisk =
	::ChainstateActive().CoinsTip().AccessCoin(txin.prevout);
	assert(!coinFromDisk.IsSpent());
	assert(coinFromDisk.GetTxOut() == coin.GetTxOut());
	}
	}

	// Call CheckInputScripts() to cache signature and script validity against
	// current tip consensus rules.
	return CheckInputScripts(tx, state, view, flags, /* cacheSigStore = */ true,
	/* cacheFullScriptStore = */ true, txdata,
	nSigChecksOut);
	}

	namespace {

	class MemPoolAccept {
	public:
	MemPoolAccept(CTxMemPool &mempool)
	: m_pool(mempool), m_view(&m_dummy),
	m_viewmempool(&::ChainstateActive().CoinsTip(), m_pool),
	m_limit_ancestors(
	gArgs.GetArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT)),
	m_limit_ancestor_size(
	gArgs.GetArg("-limitancestorsize", DEFAULT_ANCESTOR_SIZE_LIMIT) *
	1000),
	m_limit_descendants(
	gArgs.GetArg("-limitdescendantcount", DEFAULT_DESCENDANT_LIMIT)),
	m_limit_descendant_size(gArgs.GetArg("-limitdescendantsize",
	DEFAULT_DESCENDANT_SIZE_LIMIT) *
	1000) {}

	// We put the arguments we're handed into a struct, so we can pass them
	// around easier.
	struct ATMPArgs {
	const Config &m_config;
	TxValidationState &m_state;
	const int64_t m_accept_time;
	const bool m_bypass_limits;
	/*
	* Return any outpoints which were not previously present in the coins
	* cache, but were added as a result of validating the tx for mempool
	* acceptance. This allows the caller to optionally remove the cache
	* additions if the associated transaction ends up being rejected by
	* the mempool.
	*/
	std::vector<COutPoint> &m_coins_to_uncache;
	const bool m_test_accept;
	Amount *m_fee_out;
	};

	// Single transaction acceptance
	bool AcceptSingleTransaction(const CTransactionRef &ptx, ATMPArgs &args)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	private:
	// All the intermediate state that gets passed between the various levels
	// of checking a given transaction.
	struct Workspace {
	Workspace(const CTransactionRef &ptx,
	const uint32_t next_block_script_verify_flags)
	: m_ptx(ptx),
	m_next_block_script_verify_flags(next_block_script_verify_flags) {
	}
	CTxMemPool::setEntries m_ancestors;
	std::unique_ptr<CTxMemPoolEntry> m_entry;

	Amount m_modified_fees;

	const CTransactionRef &m_ptx;

	// ABC specific flags that are used in both PreChecks and
	// ConsensusScriptChecks
	const uint32_t m_next_block_script_verify_flags;
	int m_sig_checks_standard;
	};

	// Run the policy checks on a given transaction, excluding any script
	// checks. Looks up inputs, calculates feerate, considers replacement,
	// evaluates package limits, etc. As this function can be invoked for "free"
	// by a peer, only tests that are fast should be done here (to avoid CPU
	// DoS).
	bool PreChecks(ATMPArgs &args, Workspace &ws)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs);

	// Re-run the script checks, using consensus flags, and try to cache the
	// result in the scriptcache. This should be done after
	// PolicyScriptChecks(). This requires that all inputs either be in our
	// utxo set or in the mempool.
	bool ConsensusScriptChecks(ATMPArgs &args, Workspace &ws,
	PrecomputedTransactionData &txdata)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	// Try to add the transaction to the mempool, removing any conflicts first.
	// Returns true if the transaction is in the mempool after any size
	// limiting is performed, false otherwise.
	bool Finalize(ATMPArgs &args, Workspace &ws)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_pool.cs);

	private:
	CTxMemPool &m_pool;
	CCoinsViewCache m_view;
	CCoinsViewMemPool m_viewmempool;
	CCoinsView m_dummy;

	// The package limits in effect at the time of invocation.
	const size_t m_limit_ancestors;
	const size_t m_limit_ancestor_size;
	// These may be modified while evaluating a transaction (eg to account for
	// in-mempool conflicts; see below).
	size_t m_limit_descendants;
	size_t m_limit_descendant_size;
	};

	bool MemPoolAccept::PreChecks(ATMPArgs &args, Workspace &ws) {
	const CTransactionRef &ptx = ws.m_ptx;
	const CTransaction &tx = *ws.m_ptx;
	const TxId &txid = ws.m_ptx->GetId();

	// Copy/alias what we need out of args
	TxValidationState &state = args.m_state;
	const int64_t nAcceptTime = args.m_accept_time;
	const bool bypass_limits = args.m_bypass_limits;
	std::vector<COutPoint> &coins_to_uncache = args.m_coins_to_uncache;

	// Alias what we need out of ws
	CTxMemPool::setEntries &setAncestors = ws.m_ancestors;
	std::unique_ptr<CTxMemPoolEntry> &entry = ws.m_entry;
	Amount &nModifiedFees = ws.m_modified_fees;

	// Coinbase is only valid in a block, not as a loose transaction.
	if (!CheckRegularTransaction(tx, state)) {
	// state filled in by CheckRegularTransaction.
	return false;
	}

	// Rather not work on nonstandard transactions (unless -testnet)
	std::string reason;
	if (fRequireStandard && !IsStandardTx(tx, reason)) {
	return state.Invalid(TxValidationResult::TX_NOT_STANDARD, 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.
	TxValidationState ctxState;
	if (!ContextualCheckTransactionForCurrentBlock(
	args.m_config.GetChainParams().GetConsensus(), tx, ctxState,
	STANDARD_LOCKTIME_VERIFY_FLAGS)) {
	// We copy the state from a dummy to ensure we don't increase the
	// ban score of peer for transaction that could be valid in the future.
	return state.Invalid(TxValidationResult::TX_PREMATURE_SPEND,
	ctxState.GetRejectReason(),
	ctxState.GetDebugMessage());
	}

	// Is it already in the memory pool?
	if (m_pool.exists(txid)) {
	return state.Invalid(TxValidationResult::TX_CONFLICT,
	"txn-already-in-mempool");
	}

	// Check for conflicts with in-memory transactions
	for (const CTxIn &txin : tx.vin) {
	auto itConflicting = m_pool.mapNextTx.find(txin.prevout);
	if (itConflicting != m_pool.mapNextTx.end()) {
	// Disable replacement feature for good
	return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY,
	"txn-mempool-conflict");
	}
	}

	LockPoints lp;
	m_view.SetBackend(m_viewmempool);

	CCoinsViewCache &coins_cache = ::ChainstateActive().CoinsTip();
	// Do all inputs exist?
	for (const CTxIn &txin : tx.vin) {
	if (!coins_cache.HaveCoinInCache(txin.prevout)) {
	coins_to_uncache.push_back(txin.prevout);
	}

	// Note: this call may add txin.prevout to the coins cache
	// (coins_cache.cacheCoins) by way of FetchCoin(). It should be
	// removed later (via coins_to_uncache) if this tx turns out to be
	// invalid.
	if (!m_view.HaveCoin(txin.prevout)) {
	// Are inputs missing because we already have the tx?
	for (size_t out = 0; out < tx.vout.size(); out++) {
	// Optimistically just do efficient check of cache for
	// outputs.
	if (coins_cache.HaveCoinInCache(COutPoint(txid, out))) {
	return state.Invalid(TxValidationResult::TX_CONFLICT,
	"txn-already-known");
	}
	}

	// Otherwise assume this might be an orphan tx for which we just
	// haven't seen parents yet.
	return state.Invalid(TxValidationResult::TX_MISSING_INPUTS,
	"bad-txns-inputs-missingorspent");
	}
	}

	// Are the actual inputs available?
	if (!m_view.HaveInputs(tx)) {
	return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY,
	"bad-txns-inputs-spent");
	}

	// Bring the best block into scope.
	m_view.GetBestBlock();

	// we have all inputs cached now, so switch back to dummy (to protect
	// against bugs where we pull more inputs from disk that miss being
	// added to coins_to_uncache)
	m_view.SetBackend(m_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(m_pool, tx, STANDARD_LOCKTIME_VERIFY_FLAGS, &lp)) {
	return state.Invalid(TxValidationResult::TX_PREMATURE_SPEND,
	"non-BIP68-final");
	}

	Amount nFees = Amount::zero();
	if (!Consensus::CheckTxInputs(tx, state, m_view, GetSpendHeight(m_view),
	nFees)) {
	// state filled in by CheckTxInputs
	return false;
	}

	// If fee_out is passed, return the fee to the caller
	if (args.m_fee_out) {
	*args.m_fee_out = nFees;
	}

	// Check for non-standard pay-to-script-hash in inputs
	if (fRequireStandard &&
	!AreInputsStandard(tx, m_view, ws.m_next_block_script_verify_flags)) {
	return state.Invalid(TxValidationResult::TX_INPUTS_NOT_STANDARD,
	"bad-txns-nonstandard-inputs");
	}

	// nModifiedFees includes any fee deltas from PrioritiseTransaction
	nModifiedFees = nFees;
	m_pool.ApplyDelta(txid, nModifiedFees);

	// 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 Coin &coin = m_view.AccessCoin(txin.prevout);
	if (coin.IsCoinBase()) {
	fSpendsCoinbase = true;
	break;
	}
	}

	unsigned int nSize = tx.GetTotalSize();

	// No transactions are allowed below minRelayTxFee except from disconnected
	// blocks.
	// Do not change this to use virtualsize without coordinating a network
	// policy upgrade.
	if (!bypass_limits && nModifiedFees < minRelayTxFee.GetFee(nSize)) {
	return state.Invalid(
	TxValidationResult::TX_MEMPOOL_POLICY, "min relay fee not met",
	strprintf("%d < %d", nModifiedFees, ::minRelayTxFee.GetFee(nSize)));
	}

	// Validate input scripts against standard script flags.
	const uint32_t scriptVerifyFlags =
	ws.m_next_block_script_verify_flags \| STANDARD_SCRIPT_VERIFY_FLAGS;
	PrecomputedTransactionData txdata(tx);
	if (!CheckInputScripts(tx, state, m_view, scriptVerifyFlags, true, false,
	txdata, ws.m_sig_checks_standard)) {
	// State filled in by CheckInputScripts
	return false;
	}

	entry.reset(new CTxMemPoolEntry(ptx, nFees, nAcceptTime,
	::ChainActive().Height(), fSpendsCoinbase,
	ws.m_sig_checks_standard, lp));

	unsigned int nVirtualSize = entry->GetTxVirtualSize();

	Amount mempoolRejectFee =
	m_pool
	.GetMinFee(gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) *
	1000000)
	.GetFee(nVirtualSize);
	if (!bypass_limits && mempoolRejectFee > Amount::zero() &&
	nModifiedFees < mempoolRejectFee) {
	return state.Invalid(
	TxValidationResult::TX_MEMPOOL_POLICY, "mempool min fee not met",
	strprintf("%d < %d", nModifiedFees, mempoolRejectFee));
	}

	// Calculate in-mempool ancestors, up to a limit.
	std::string errString;
	if (!m_pool.CalculateMemPoolAncestors(
	*entry, setAncestors, m_limit_ancestors, m_limit_ancestor_size,
	m_limit_descendants, m_limit_descendant_size, errString)) {
	return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY,
	"too-long-mempool-chain", errString);
	}
	return true;
	}

	bool MemPoolAccept::ConsensusScriptChecks(ATMPArgs &args, Workspace &ws,
	PrecomputedTransactionData &txdata) {
	const CTransaction &tx = *ws.m_ptx;
	const TxId &txid = tx.GetId();

	TxValidationState &state = args.m_state;

	// Check again against the next block's script verification flags
	// to cache our script execution flags.
	//
	// This is also useful 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 (using TestBlockValidity), however allowing such
	// transactions into the mempool can be exploited as a DoS attack.
	int nSigChecksConsensus;
	if (!CheckInputsFromMempoolAndCache(tx, state, m_view, m_pool,
	ws.m_next_block_script_verify_flags,
	txdata, nSigChecksConsensus)) {
	// This can occur under some circumstances, if the node receives an
	// unrequested tx which is invalid due to new consensus rules not
	// being activated yet (during IBD).
	return error("%s: BUG! PLEASE REPORT THIS! CheckInputScripts failed "
	"against next-block but not STANDARD flags %s, %s",
	__func__, txid.ToString(), state.ToString());
	}

	if (ws.m_sig_checks_standard != nSigChecksConsensus) {
	// We can't accept this transaction as we've used the standard count
	// for the mempool/mining, but the consensus count will be enforced
	// in validation (we don't want to produce bad block templates).
	return error(
	"%s: BUG! PLEASE REPORT THIS! SigChecks count differed between "
	"standard and consensus flags in %s",
	__func__, txid.ToString());
	}
	return true;
	}

	bool MemPoolAccept::Finalize(ATMPArgs &args, Workspace &ws) {
	const TxId &txid = ws.m_ptx->GetId();
	TxValidationState &state = args.m_state;
	const bool bypass_limits = args.m_bypass_limits;

	CTxMemPool::setEntries &setAncestors = ws.m_ancestors;
	std::unique_ptr<CTxMemPoolEntry> &entry = ws.m_entry;

	// Store transaction in memory.
	m_pool.addUnchecked(*entry, setAncestors);

	// Trim mempool and check if tx was trimmed.
	if (!bypass_limits) {
	m_pool.LimitSize(
	gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000,
	std::chrono::hours{
	gArgs.GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY)});
	if (!m_pool.exists(txid)) {
	return state.Invalid(TxValidationResult::TX_MEMPOOL_POLICY,
	"mempool full");
	}
	}
	return true;
	}

	bool MemPoolAccept::AcceptSingleTransaction(const CTransactionRef &ptx,
	ATMPArgs &args) {
	AssertLockHeld(cs_main);
	// mempool "read lock" (held through
	// GetMainSignals().TransactionAddedToMempool())
	LOCK(m_pool.cs);

	Workspace workspace(ptx, GetNextBlockScriptFlags(
	args.m_config.GetChainParams().GetConsensus(),
	::ChainActive().Tip()));

	if (!PreChecks(args, workspace)) {
	return false;
	}

	// Only compute the precomputed transaction data if we need to verify
	// scripts (ie, other policy checks pass). We perform the inexpensive
	// checks first and avoid hashing and signature verification unless those
	// checks pass, to mitigate CPU exhaustion denial-of-service attacks.
	PrecomputedTransactionData txdata(*ptx);

	if (!ConsensusScriptChecks(args, workspace, txdata)) {
	return false;
	}

	// Tx was accepted, but not added
	if (args.m_test_accept) {
	return true;
	}

	if (!Finalize(args, workspace)) {
	return false;
	}

	GetMainSignals().TransactionAddedToMempool(
	ptx, m_pool.GetAndIncrementSequence());

	return true;
	}

	} // namespace

	/**
	* (try to) add transaction to memory pool with a specified acceptance time.
	*/
	static bool
	AcceptToMemoryPoolWithTime(const Config &config, CTxMemPool &pool,
	TxValidationState &state, const CTransactionRef &tx,
	int64_t nAcceptTime, bool bypass_limits,
	bool test_accept, Amount *fee_out = nullptr)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
	AssertLockHeld(cs_main);
	std::vector<COutPoint> coins_to_uncache;
	MemPoolAccept::ATMPArgs args{
	config, state, nAcceptTime, bypass_limits,
	coins_to_uncache, test_accept, fee_out};
	bool res = MemPoolAccept(pool).AcceptSingleTransaction(tx, args);
	if (!res) {
	// Remove coins that were not present in the coins cache before calling
	// ATMPW; this is to prevent memory DoS in case we receive a large
	// number of invalid transactions that attempt to overrun the in-memory
	// coins cache
	// (`CCoinsViewCache::cacheCoins`).

	for (const COutPoint &outpoint : coins_to_uncache) {
	::ChainstateActive().CoinsTip().Uncache(outpoint);
	}
	}

	// After we've (potentially) uncached entries, ensure our coins cache is
	// still within its size limits
	BlockValidationState stateDummy;
	::ChainstateActive().FlushStateToDisk(config.GetChainParams(), stateDummy,
	FlushStateMode::PERIODIC);
	return res;
	}

	bool AcceptToMemoryPool(const Config &config, CTxMemPool &pool,
	TxValidationState &state, const CTransactionRef &tx,
	bool bypass_limits, bool test_accept, Amount *fee_out) {
	return AcceptToMemoryPoolWithTime(config, pool, state, tx, GetTime(),
	bypass_limits, test_accept, fee_out);
	}

	CTransactionRef GetTransaction(const CBlockIndex *const block_index,
	const CTxMemPool *const mempool,
	const TxId &txid,
	const Consensus::Params &consensusParams,
	BlockHash &hashBlock) {
	LOCK(cs_main);

	if (block_index) {
	CBlock block;
	if (ReadBlockFromDisk(block, block_index, consensusParams)) {
	for (const auto &tx : block.vtx) {
	if (tx->GetId() == txid) {
	hashBlock = block_index->GetBlockHash();
	return tx;
	}
	}
	}
	return nullptr;
	}
	if (mempool) {
	CTransactionRef ptx = mempool->get(txid);
	if (ptx) {
	return ptx;
	}
	}
	if (g_txindex) {
	CTransactionRef tx;
	if (g_txindex->FindTx(txid, hashBlock, tx)) {
	return tx;
	}
	}
	return nullptr;
	}

	//////////////////////////////////////////////////////////////////////////////
	//
	// CBlock and CBlockIndex
	//

	static bool WriteBlockToDisk(const CBlock &block, FlatFilePos &pos,
	const CMessageHeader::MessageMagic &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(block, fileout.GetVersion());
	fileout << 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;
	}

	Amount 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 Amount::zero();
	}

	Amount nSubsidy = 50 * COIN;
	// Subsidy is cut in half every 210,000 blocks which will occur
	// approximately every 4 years.
	return ((nSubsidy / SATOSHI) >> halvings) * SATOSHI;
	}

	CoinsViews::CoinsViews(std::string ldb_name, size_t cache_size_bytes,
	bool in_memory, bool should_wipe)
	: m_dbview(GetDataDir() / ldb_name, cache_size_bytes, in_memory,
	should_wipe),
	m_catcherview(&m_dbview) {}

	void CoinsViews::InitCache() {
	m_cacheview = std::make_unique<CCoinsViewCache>(&m_catcherview);
	}

	CChainState::CChainState(CTxMemPool &mempool, BlockManager &blockman,
	BlockHash from_snapshot_blockhash)
	: m_blockman(blockman), m_mempool(mempool),
	m_from_snapshot_blockhash(from_snapshot_blockhash) {}

	void CChainState::InitCoinsDB(size_t cache_size_bytes, bool in_memory,
	bool should_wipe, std::string leveldb_name) {
	if (!m_from_snapshot_blockhash.IsNull()) {
	leveldb_name += "_" + m_from_snapshot_blockhash.ToString();
	}
	m_coins_views = std::make_unique<CoinsViews>(leveldb_name, cache_size_bytes,
	in_memory, should_wipe);
	}

	void CChainState::InitCoinsCache(size_t cache_size_bytes) {
	assert(m_coins_views != nullptr);
	m_coinstip_cache_size_bytes = cache_size_bytes;
	m_coins_views->InitCache();
	}

	// Note that though this is marked const, we may end up modifying
	// `m_cached_finished_ibd`, which is a performance-related implementation
	// detail. This function must be marked `const` so that `CValidationInterface`
	// clients (which are given a `const CChainState*`) can call it.
	//
	bool CChainState::IsInitialBlockDownload() const {
	// Optimization: pre-test latch before taking the lock.
	if (m_cached_finished_ibd.load(std::memory_order_relaxed)) {
	return false;
	}

	LOCK(cs_main);
	if (m_cached_finished_ibd.load(std::memory_order_relaxed)) {
	return false;
	}
	if (fImporting \|\| fReindex) {
	return true;
	}
	if (m_chain.Tip() == nullptr) {
	return true;
	}
	if (m_chain.Tip()->nChainWork < nMinimumChainWork) {
	return true;
	}
	if (m_chain.Tip()->GetBlockTime() < (GetTime() - nMaxTipAge)) {
	return true;
	}
	LogPrintf("Leaving InitialBlockDownload (latching to false)\n");
	m_cached_finished_ibd.store(true, std::memory_order_relaxed);
	return false;
	}

	static CBlockIndex const *pindexBestForkTip = nullptr;
	static CBlockIndex const *pindexBestForkBase = nullptr;

	static void AlertNotify(const std::string &strMessage) {
	uiInterface.NotifyAlertChanged();
	#if defined(HAVE_SYSTEM)
	std::string strCmd = gArgs.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);

	std::thread t(runCommand, strCmd);
	// thread runs free
	t.detach();
	#endif
	}

	static void CheckForkWarningConditions() EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
	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 (::ChainstateActive().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 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);
	}
	}

	static void CheckForkWarningConditionsOnNewFork(CBlockIndex *pindexNewForkTip)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
	AssertLockHeld(cs_main);
	// If we are on a fork that is sufficiently large, set a warning flag.
	const CBlockIndex *pfork = ::ChainActive().FindFork(pindexNewForkTip);

	// 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 \|\|
	pindexNewForkTip->nHeight > pindexBestForkTip->nHeight) &&
	pindexNewForkTip->nChainWork - pfork->nChainWork >
	(GetBlockProof(pfork) 7) &&
	::ChainActive().Height() - pindexNewForkTip->nHeight < 72) {
	pindexBestForkTip = pindexNewForkTip;
	pindexBestForkBase = pfork;
	}

	CheckForkWarningConditions();
	}

	// Called both upon regular invalid block discovery and InvalidateBlock
	void CChainState::InvalidChainFound(CBlockIndex *pindexNew) {
	AssertLockHeld(cs_main);
	if (!pindexBestInvalid \|\|
	pindexNew->nChainWork > pindexBestInvalid->nChainWork) {
	pindexBestInvalid = pindexNew;
	}
	if (pindexBestHeader != nullptr &&
	pindexBestHeader->GetAncestor(pindexNew->nHeight) == pindexNew) {
	pindexBestHeader = ::ChainActive().Tip();
	}

	// If the invalid chain found is supposed to be finalized, we need to move
	// back the finalization point.
	if (IsBlockFinalized(pindexNew)) {
	m_finalizedBlockIndex = pindexNew->pprev;
	}

	LogPrintf("%s: invalid block=%s height=%d log2_work=%f date=%s\n",
	__func__, pindexNew->GetBlockHash().ToString(),
	pindexNew->nHeight,
	log(pindexNew->nChainWork.getdouble()) / log(2.0),
	FormatISO8601DateTime(pindexNew->GetBlockTime()));
	CBlockIndex *tip = ::ChainActive().Tip();
	assert(tip);
	LogPrintf("%s: current best=%s height=%d log2_work=%f date=%s\n",
	__func__, tip->GetBlockHash().ToString(),
	::ChainActive().Height(),
	log(tip->nChainWork.getdouble()) / log(2.0),
	FormatISO8601DateTime(tip->GetBlockTime()));
	}

	// Same as InvalidChainFound, above, except not called directly from
	// InvalidateBlock, which does its own setBlockIndexCandidates management.
	void CChainState::InvalidBlockFound(CBlockIndex *pindex,
	const BlockValidationState &state) {
	if (state.GetResult() != BlockValidationResult::BLOCK_MUTATED) {
	pindex->nStatus = pindex->nStatus.withFailed();
	m_blockman.m_failed_blocks.insert(pindex);
	setDirtyBlockIndex.insert(pindex);
	InvalidChainFound(pindex);
	}
	}

	void SpendCoins(CCoinsViewCache &view, const CTransaction &tx, CTxUndo &txundo,
	int nHeight) {
	// Mark inputs spent.
	if (tx.IsCoinBase()) {
	return;
	}

	txundo.vprevout.reserve(tx.vin.size());
	for (const CTxIn &txin : tx.vin) {
	txundo.vprevout.emplace_back();
	bool is_spent = view.SpendCoin(txin.prevout, &txundo.vprevout.back());
	assert(is_spent);
	}
	}

	void UpdateCoins(CCoinsViewCache &view, const CTransaction &tx, CTxUndo &txundo,
	int nHeight) {
	SpendCoins(view, tx, txundo, nHeight);
	AddCoins(view, tx, nHeight);
	}

	void UpdateCoins(CCoinsViewCache &view, const CTransaction &tx, int nHeight) {
	// Mark inputs spent.
	if (!tx.IsCoinBase()) {
	for (const CTxIn &txin : tx.vin) {
	bool is_spent = view.SpendCoin(txin.prevout);
	assert(is_spent);
	}
	}

	// Add outputs.
	AddCoins(view, tx, nHeight);
	}

	bool CScriptCheck::operator()() {
	const CScript &scriptSig = ptxTo->vin[nIn].scriptSig;
	if (!VerifyScript(scriptSig, m_tx_out.scriptPubKey, nFlags,
	CachingTransactionSignatureChecker(
	ptxTo, nIn, m_tx_out.nValue, cacheStore, txdata),
	metrics, &error)) {
	return false;
	}
	if ((pTxLimitSigChecks &&
	!pTxLimitSigChecks->consume_and_check(metrics.nSigChecks)) \|\|
	(pBlockLimitSigChecks &&
	!pBlockLimitSigChecks->consume_and_check(metrics.nSigChecks))) {
	// we can't assign a meaningful script error (since the script
	// succeeded), but remove the ScriptError::OK which could be
	// misinterpreted.
	error = ScriptError::SIGCHECKS_LIMIT_EXCEEDED;
	return false;
	}
	return true;
	}

	int GetSpendHeight(const CCoinsViewCache &inputs) {
	LOCK(cs_main);
	CBlockIndex *pindexPrev = LookupBlockIndex(inputs.GetBestBlock());
	return pindexPrev->nHeight + 1;
	}

	bool CheckInputScripts(const CTransaction &tx, TxValidationState &state,
	const CCoinsViewCache &inputs, const uint32_t flags,
	bool sigCacheStore, bool scriptCacheStore,
	const PrecomputedTransactionData &txdata,
	int &nSigChecksOut, TxSigCheckLimiter &txLimitSigChecks,
	CheckInputsLimiter *pBlockLimitSigChecks,
	std::vector<CScriptCheck> *pvChecks) {
	AssertLockHeld(cs_main);
	assert(!tx.IsCoinBase());

	if (pvChecks) {
	pvChecks->reserve(tx.vin.size());
	}

	// First check if script executions have been cached with the same flags.
	// Note that this assumes that the inputs provided are correct (ie that the
	// transaction hash which is in tx's prevouts properly commits to the
	// scriptPubKey in the inputs view of that transaction).
	ScriptCacheKey hashCacheEntry(tx, flags);
	if (IsKeyInScriptCache(hashCacheEntry, !scriptCacheStore, nSigChecksOut)) {
	if (!txLimitSigChecks.consume_and_check(nSigChecksOut) \|\|
	(pBlockLimitSigChecks &&
	!pBlockLimitSigChecks->consume_and_check(nSigChecksOut))) {
	return state.Invalid(TxValidationResult::TX_CONSENSUS,
	"too-many-sigchecks");
	}
	return true;
	}

	int nSigChecksTotal = 0;

	for (size_t i = 0; i < tx.vin.size(); i++) {
	const COutPoint &prevout = tx.vin[i].prevout;
	const Coin &coin = inputs.AccessCoin(prevout);
	assert(!coin.IsSpent());

	// We very carefully only pass in things to CScriptCheck which are
	// clearly committed to by tx's hash. This provides a sanity
	// check that our caching is not introducing consensus failures through
	// additional data in, eg, the coins being spent being checked as a part
	// of CScriptCheck.

	// Verify signature
	CScriptCheck check(coin.GetTxOut(), tx, i, flags, sigCacheStore, txdata,
	&txLimitSigChecks, pBlockLimitSigChecks);

	// If pvChecks is not null, defer the check execution to the caller.
	if (pvChecks) {
	pvChecks->push_back(std::move(check));
	continue;
	}

	if (!check()) {
	ScriptError scriptError = check.GetScriptError();
	// Compute flags without the optional standardness flags.
	// This differs from MANDATORY_SCRIPT_VERIFY_FLAGS as it contains
	// additional upgrade flags (see AcceptToMemoryPoolWorker variable
	// extraFlags).
	uint32_t mandatoryFlags =
	flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS;
	if (flags != mandatoryFlags) {
	// Check whether the failure was caused by a non-mandatory
	// script verification check. If so, ensure we return
	// NOT_STANDARD instead of CONSENSUS to avoid downstream users
	// splitting the network between upgraded and non-upgraded nodes
	// by banning CONSENSUS-failing data providers.
	CScriptCheck check2(coin.GetTxOut(), tx, i, mandatoryFlags,
	sigCacheStore, txdata);
	if (check2()) {
	return state.Invalid(
	TxValidationResult::TX_NOT_STANDARD,
	strprintf("non-mandatory-script-verify-flag (%s)",
	ScriptErrorString(scriptError)));
	}
	// update the error message to reflect the mandatory violation.
	scriptError = check2.GetScriptError();
	}

	// MANDATORY flag failures correspond to
	// TxValidationResult::TX_CONSENSUS. Because CONSENSUS failures are
	// the most serious case of validation failures, we may need to
	// consider using RECENT_CONSENSUS_CHANGE for any script failure
	// that could be due to non-upgraded nodes which we may want to
	// support, to avoid splitting the network (but this depends on the
	// details of how net_processing handles such errors).
	return state.Invalid(
	TxValidationResult::TX_CONSENSUS,
	strprintf("mandatory-script-verify-flag-failed (%s)",
	ScriptErrorString(scriptError)));
	}

	nSigChecksTotal += check.GetScriptExecutionMetrics().nSigChecks;
	}

	nSigChecksOut = nSigChecksTotal;

	if (scriptCacheStore && !pvChecks) {
	// We executed all of the provided scripts, and were told to cache the
	// result. Do so now.
	AddKeyInScriptCache(hashCacheEntry, nSigChecksTotal);
	}

	return true;
	}

	static bool UndoWriteToDisk(const CBlockUndo &blockundo, FlatFilePos &pos,
	const BlockHash &hashBlock,
	const CMessageHeader::MessageMagic &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(blockundo, fileout.GetVersion());
	fileout << 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 CBlockIndex *pindex) {
	FlatFilePos pos = pindex->GetUndoPos();
	if (pos.IsNull()) {
	return error("%s: no undo data available", __func__);
	}

	// 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;
	// We need a CHashVerifier as reserializing may lose data
	CHashVerifier<CAutoFile> verifier(&filein);
	try {
	verifier << pindex->pprev->GetBlockHash();
	verifier >> blockundo;
	filein >> hashChecksum;
	} catch (const std::exception &e) {
	return error("%s: Deserialize or I/O error - %s", __func__, e.what());
	}

	// Verify checksum
	if (hashChecksum != verifier.GetHash()) {
	return error("%s: Checksum mismatch", __func__);
	}

	return true;
	}

	/** Abort with a message */
	static bool AbortNode(const std::string &strMessage,
	bilingual_str user_message = bilingual_str()) {
	SetMiscWarning(Untranslated(strMessage));
	LogPrintf("*** %s\n", strMessage);
	if (!user_message.empty()) {
	user_message =
	_("A fatal internal error occurred, see debug.log for details");
	}
	AbortError(user_message);
	StartShutdown();
	return false;
	}

	static bool AbortNode(BlockValidationState &state,
	const std::string &strMessage,
	const bilingual_str &userMessage = bilingual_str()) {
	AbortNode(strMessage, userMessage);
	return state.Error(strMessage);
	}

	/** Restore the UTXO in a Coin at a given COutPoint. */
	DisconnectResult UndoCoinSpend(const Coin &undo, CCoinsViewCache &view,
	const COutPoint &out) {
	bool fClean = true;

	if (view.HaveCoin(out)) {
	// Overwriting transaction output.
	fClean = false;
	}

	if (undo.GetHeight() == 0) {
	// Missing undo metadata (height and coinbase). Older versions included
	// this information only in undo records for the last spend of a
	// transactions' outputs. This implies that it must be present for some
	// other output of the same tx.
	const Coin &alternate = AccessByTxid(view, out.GetTxId());
	if (alternate.IsSpent()) {
	// Adding output for transaction without known metadata
	return DisconnectResult::FAILED;
	}

	// This is somewhat ugly, but hopefully utility is limited. This is only
	// useful when working from legacy on disck data. In any case, putting
	// the correct information in there doesn't hurt.
	const_cast<Coin &>(undo) = Coin(undo.GetTxOut(), alternate.GetHeight(),
	alternate.IsCoinBase());
	}

	// If the coin already exists as an unspent coin in the cache, then the
	// possible_overwrite parameter to AddCoin must be set to true. We have
	// already checked whether an unspent coin exists above using HaveCoin, so
	// we don't need to guess. When fClean is false, an unspent coin already
	// existed and it is an overwrite.
	view.AddCoin(out, std::move(undo), !fClean);

	return fClean ? DisconnectResult::OK : DisconnectResult::UNCLEAN;
	}

	/**
	* Undo the effects of this block (with given index) on the UTXO set represented
	* by coins. When FAILED is returned, view is left in an indeterminate state.
	*/
	DisconnectResult CChainState::DisconnectBlock(const CBlock &block,
	const CBlockIndex *pindex,
	CCoinsViewCache &view) {
	CBlockUndo blockUndo;
	if (!UndoReadFromDisk(blockUndo, pindex)) {
	error("DisconnectBlock(): failure reading undo data");
	return DisconnectResult::FAILED;
	}

	return ApplyBlockUndo(blockUndo, block, pindex, view);
	}

	DisconnectResult ApplyBlockUndo(const CBlockUndo &blockUndo,
	const CBlock &block, const CBlockIndex *pindex,
	CCoinsViewCache &view) {
	bool fClean = true;

	if (blockUndo.vtxundo.size() + 1 != block.vtx.size()) {
	error("DisconnectBlock(): block and undo data inconsistent");
	return DisconnectResult::FAILED;
	}

	// First, restore inputs.
	for (size_t i = 1; i < block.vtx.size(); i++) {
	const CTransaction &tx = *(block.vtx[i]);
	const CTxUndo &txundo = blockUndo.vtxundo[i - 1];
	if (txundo.vprevout.size() != tx.vin.size()) {
	error("DisconnectBlock(): transaction and undo data inconsistent");
	return DisconnectResult::FAILED;
	}

	for (size_t j = 0; j < tx.vin.size(); j++) {
	const COutPoint &out = tx.vin[j].prevout;
	const Coin &undo = txundo.vprevout[j];
	DisconnectResult res = UndoCoinSpend(undo, view, out);
	if (res == DisconnectResult::FAILED) {
	return DisconnectResult::FAILED;
	}
	fClean = fClean && res != DisconnectResult::UNCLEAN;
	}
	}

	// Second, revert created outputs.
	for (const auto &ptx : block.vtx) {
	const CTransaction &tx = *ptx;
	const TxId &txid = tx.GetId();
	const bool is_coinbase = tx.IsCoinBase();

	// Check that all outputs are available and match the outputs in the
	// block itself exactly.
	for (size_t o = 0; o < tx.vout.size(); o++) {
	if (tx.vout[o].scriptPubKey.IsUnspendable()) {
	continue;
	}

	COutPoint out(txid, o);
	Coin coin;
	bool is_spent = view.SpendCoin(out, &coin);
	if (!is_spent \|\| tx.vout[o] != coin.GetTxOut() \|\|
	uint32_t(pindex->nHeight) != coin.GetHeight() \|\|
	is_coinbase != coin.IsCoinBase()) {
	// transaction output mismatch
	fClean = false;
	}
	}
	}

	// Move best block pointer to previous block.
	view.SetBestBlock(block.hashPrevBlock);

	return fClean ? DisconnectResult::OK : DisconnectResult::UNCLEAN;
	}

	static void FlushUndoFile(int block_file, bool finalize = false) {
	FlatFilePos undo_pos_old(block_file, vinfoBlockFile[block_file].nUndoSize);
	if (!UndoFileSeq().Flush(undo_pos_old, finalize)) {
	AbortNode("Flushing undo file to disk failed. This is likely the "
	"result of an I/O error.");
	}
	}

	static void FlushBlockFile(bool fFinalize = false, bool finalize_undo = false) {
	LOCK(cs_LastBlockFile);
	FlatFilePos block_pos_old(nLastBlockFile,
	vinfoBlockFile[nLastBlockFile].nSize);
	if (!BlockFileSeq().Flush(block_pos_old, fFinalize)) {
	AbortNode("Flushing block file to disk failed. This is likely the "
	"result of an I/O error.");
	}
	// we do not always flush the undo file, as the chain tip may be lagging
	// behind the incoming blocks,
	// e.g. during IBD or a sync after a node going offline
	if (!fFinalize \|\| finalize_undo) {
	FlushUndoFile(nLastBlockFile, finalize_undo);
	}
	}

	static bool FindUndoPos(BlockValidationState &state, int nFile,
	FlatFilePos &pos, unsigned int nAddSize);

	static bool WriteUndoDataForBlock(const CBlockUndo &blockundo,
	BlockValidationState &state,
	CBlockIndex *pindex,
	const CChainParams &chainparams) {
	// Write undo information to disk
	if (pindex->GetUndoPos().IsNull()) {
	FlatFilePos _pos;
	if (!FindUndoPos(state, pindex->nFile, _pos,
	::GetSerializeSize(blockundo, CLIENT_VERSION) + 40)) {
	return error("ConnectBlock(): FindUndoPos failed");
	}
	if (!UndoWriteToDisk(blockundo, _pos, pindex->pprev->GetBlockHash(),
	chainparams.DiskMagic())) {
	return AbortNode(state, "Failed to write undo data");
	}
	// rev files are written in block height order, whereas blk files are
	// written as blocks come in (often out of order) we want to flush the
	// rev (undo) file once we've written the last block, which is indicated
	// by the last height in the block file info as below; note that this
	// does not catch the case where the undo writes are keeping up with the
	// block writes (usually when a synced up node is getting newly mined
	// blocks) -- this case is caught in the FindBlockPos function
	if (_pos.nFile < nLastBlockFile &&
	static_cast<uint32_t>(pindex->nHeight) ==
	vinfoBlockFile[_pos.nFile].nHeightLast) {
	FlushUndoFile(_pos.nFile, true);
	}

	// update nUndoPos in block index
	pindex->nUndoPos = _pos.nPos;
	pindex->nStatus = pindex->nStatus.withUndo();
	setDirtyBlockIndex.insert(pindex);
	}

	return true;
	}

	static CCheckQueue<CScriptCheck> scriptcheckqueue(128);

	-void ThreadScriptCheck(int worker_num) {
	- util::ThreadRename(strprintf("scriptch.%i", worker_num));
	- scriptcheckqueue.Thread();
	+void StartScriptCheckWorkerThreads(int threads_num) {
	+ scriptcheckqueue.StartWorkerThreads(threads_num);
	+}
	+
	+void StopScriptCheckWorkerThreads() {
	+ scriptcheckqueue.StopWorkerThreads();
	}

	VersionBitsCache versionbitscache GUARDED_BY(cs_main);

	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, static_cast<Consensus::DeploymentPos>(i),
	versionbitscache);
	if (state == ThresholdState::LOCKED_IN \|\|
	state == ThresholdState::STARTED) {
	nVersion \|= VersionBitsMask(
	params, static_cast<Consensus::DeploymentPos>(i));
	}
	}

	// Clear the last 4 bits (miner fund activation).
	return nVersion & ~uint32_t(0x0f);
	}

	// Returns the script flags which should be checked for the block after
	// the given block.
	static uint32_t GetNextBlockScriptFlags(const Consensus::Params &params,
	const CBlockIndex *pindex) {
	uint32_t flags = SCRIPT_VERIFY_NONE;

	// Start enforcing P2SH (BIP16)
	if ((pindex->nHeight + 1) >= params.BIP16Height) {
	flags \|= SCRIPT_VERIFY_P2SH;
	}

	// Start enforcing the DERSIG (BIP66) rule.
	if ((pindex->nHeight + 1) >= params.BIP66Height) {
	flags \|= SCRIPT_VERIFY_DERSIG;
	}

	// Start enforcing CHECKLOCKTIMEVERIFY (BIP65) rule.
	if ((pindex->nHeight + 1) >= params.BIP65Height) {
	flags \|= SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY;
	}

	// Start enforcing CSV (BIP68, BIP112 and BIP113) rule.
	if ((pindex->nHeight + 1) >= params.CSVHeight) {
	flags \|= SCRIPT_VERIFY_CHECKSEQUENCEVERIFY;
	}

	// If the UAHF is enabled, we start accepting replay protected txns
	if (IsUAHFenabled(params, pindex)) {
	flags \|= SCRIPT_VERIFY_STRICTENC;
	flags \|= SCRIPT_ENABLE_SIGHASH_FORKID;
	}

	// If the DAA HF is enabled, we start rejecting transaction that use a high
	// s in their signature. We also make sure that signature that are supposed
	// to fail (for instance in multisig or other forms of smart contracts) are
	// null.
	if (IsDAAEnabled(params, pindex)) {
	flags \|= SCRIPT_VERIFY_LOW_S;
	flags \|= SCRIPT_VERIFY_NULLFAIL;
	}

	// When the magnetic anomaly fork is enabled, we start accepting
	// transactions using the OP_CHECKDATASIG opcode and it's verify
	// alternative. We also start enforcing push only signatures and
	// clean stack.
	if (IsMagneticAnomalyEnabled(params, pindex)) {
	flags \|= SCRIPT_VERIFY_CHECKDATASIG_SIGOPS;
	flags \|= SCRIPT_VERIFY_SIGPUSHONLY;
	flags \|= SCRIPT_VERIFY_CLEANSTACK;
	}

	if (IsGravitonEnabled(params, pindex)) {
	flags \|= SCRIPT_ENABLE_SCHNORR_MULTISIG;
	flags \|= SCRIPT_VERIFY_MINIMALDATA;
	}

	if (IsPhononEnabled(params, pindex)) {
	flags \|= SCRIPT_ENFORCE_SIGCHECKS;
	}

	// We make sure this node will have replay protection during the next hard
	// fork.
	if (IsReplayProtectionEnabled(params, pindex)) {
	flags \|= SCRIPT_ENABLE_REPLAY_PROTECTION;
	}

	return flags;
	}

	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;
	static int64_t nBlocksTotal = 0;

	/**
	* Apply the effects of this block (with given index) on the UTXO set
	* represented by coins. Validity checks that depend on the UTXO set are also
	* done; ConnectBlock() can fail if those validity checks fail (among other
	* reasons).
	*/
	bool CChainState::ConnectBlock(const CBlock &block, BlockValidationState &state,
	CBlockIndex *pindex, CCoinsViewCache &view,
	const CChainParams &params,
	BlockValidationOptions options,
	bool fJustCheck) {
	AssertLockHeld(cs_main);
	assert(pindex);
	assert(*pindex->phashBlock == block.GetHash());
	int64_t nTimeStart = GetTimeMicros();

	const Consensus::Params &consensusParams = params.GetConsensus();

	// Check it again in case a previous version let a bad block in
	// NOTE: We don't currently (re-)invoke ContextualCheckBlock() or
	// ContextualCheckBlockHeader() here. This means that if we add a new
	// consensus rule that is enforced in one of those two functions, then we
	// may have let in a block that violates the rule prior to updating the
	// software, and we would NOT be enforcing the rule here. Fully solving
	// upgrade from one software version to the next after a consensus rule
	// change is potentially tricky and issue-specific.
	// Also, currently the rule against blocks more than 2 hours in the future
	// is enforced in ContextualCheckBlockHeader(); we wouldn't want to
	// re-enforce that rule here (at least until we make it impossible for
	// GetAdjustedTime() to go backward).
	if (!CheckBlock(block, state, consensusParams,
	options.withCheckPoW(!fJustCheck)
	.withCheckMerkleRoot(!fJustCheck))) {
	if (state.GetResult() == BlockValidationResult::BLOCK_MUTATED) {
	// We don't write down blocks to disk if they may have been
	// corrupted, so this should be impossible unless we're having
	// hardware problems.
	return AbortNode(state, "Corrupt block found indicating potential "
	"hardware failure; shutting down");
	}
	return error("%s: Consensus::CheckBlock: %s", __func__,
	state.ToString());
	}

	// Verify that the view's current state corresponds to the previous block
	BlockHash hashPrevBlock =
	pindex->pprev == nullptr ? BlockHash() : pindex->pprev->GetBlockHash();
	assert(hashPrevBlock == view.GetBestBlock());

	nBlocksTotal++;

	// Special case for the genesis block, skipping connection of its
	// transactions (its coinbase is unspendable)
	if (block.GetHash() == consensusParams.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 =
	m_blockman.m_block_index.find(hashAssumeValid);
	if (it != m_blockman.m_block_index.end()) {
	if (it->second->GetAncestor(pindex->nHeight) == pindex &&
	pindexBestHeader->GetAncestor(pindex->nHeight) == pindex &&
	pindexBestHeader->nChainWork >= nMinimumChainWork) {
	// This block is a member of the assumed verified chain and an
	// ancestor of the best header.
	// Script verification is skipped when connecting blocks under
	// the assumevalid block. Assuming the assumevalid 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.
	// The equivalent time check discourages hash power 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,
	consensusParams) <= 60 * 60 * 24 * 7 * 2);
	}
	}
	}

	int64_t nTime1 = GetTimeMicros();
	nTimeCheck += nTime1 - nTimeStart;
	LogPrint(BCLog::BENCH, " - Sanity checks: %.2fms [%.2fs (%.2fms/blk)]\n",
	MILLI * (nTime1 - nTimeStart), nTimeCheck * MICRO,
	nTimeCheck * MILLI / nBlocksTotal);

	// 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, CVE-2012-1909, 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->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 it's 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.

	// BIP34 requires that a block at height X (block X) has its coinbase
	// scriptSig start with a CScriptNum of X (indicated height X). The above
	// logic of no longer requiring BIP30 once BIP34 activates is flawed in the
	// case that there is a block X before the BIP34 height of 227,931 which has
	// an indicated height Y where Y is greater than X. The coinbase for block
	// X would also be a valid coinbase for block Y, which could be a BIP30
	// violation. An exhaustive search of all mainnet coinbases before the
	// BIP34 height which have an indicated height greater than the block height
	// reveals many occurrences. The 3 lowest indicated heights found are
	// 209,921, 490,897, and 1,983,702 and thus coinbases for blocks at these 3
	// heights would be the first opportunity for BIP30 to be violated.

	// The search reveals a great many blocks which have an indicated height
	// greater than 1,983,702, so we simply remove the optimization to skip
	// BIP30 checking for blocks at height 1,983,702 or higher. Before we reach
	// that block in another 25 years or so, we should take advantage of a
	// future consensus change to do a new and improved version of BIP34 that
	// will actually prevent ever creating any duplicate coinbases in the
	// future.
	static constexpr int BIP34_IMPLIES_BIP30_LIMIT = 1983702;

	// There is no potential to create a duplicate coinbase at block 209,921
	// because this is still before the BIP34 height and so explicit BIP30
	// checking is still active.

	// The final case is block 176,684 which has an indicated height of
	// 490,897. Unfortunately, this issue was not discovered until about 2 weeks
	// before block 490,897 so there was not much opportunity to address this
	// case other than to carefully analyze it and determine it would not be a
	// problem. Block 490,897 was, in fact, mined with a different coinbase than
	// block 176,684, but it is important to note that even if it hadn't been or
	// is remined on an alternate fork with a duplicate coinbase, we would still
	// not run into a BIP30 violation. This is because the coinbase for 176,684
	// is spent in block 185,956 in transaction
	// d4f7fbbf92f4a3014a230b2dc70b8058d02eb36ac06b4a0736d9d60eaa9e8781. This
	// spending transaction can't be duplicated because it also spends coinbase
	// 0328dd85c331237f18e781d692c92de57649529bd5edf1d01036daea32ffde29. This
	// coinbase has an indicated height of over 4.2 billion, and wouldn't be
	// duplicatable until that height, and it's currently impossible to create a
	// chain that long. Nevertheless we may wish to consider a future soft fork
	// which retroactively prevents block 490,897 from creating a duplicate
	// coinbase. The two historical BIP30 violations often provide a confusing
	// edge case when manipulating the UTXO and it would be simpler not to have
	// another edge case to deal with.

	// testnet3 has no blocks before the BIP34 height with indicated heights
	// post BIP34 before approximately height 486,000,000 and presumably will
	// be reset before it reaches block 1,983,702 and starts doing unnecessary
	// BIP30 checking again.
	assert(pindex->pprev);
	CBlockIndex *pindexBIP34height =
	pindex->pprev->GetAncestor(consensusParams.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() == consensusParams.BIP34Hash));

	// TODO: Remove BIP30 checking from block height 1,983,702 on, once we have
	// a consensus change that ensures coinbases at those heights can not
	// duplicate earlier coinbases.
	if (fEnforceBIP30 \|\| pindex->nHeight >= BIP34_IMPLIES_BIP30_LIMIT) {
	for (const auto &tx : block.vtx) {
	for (size_t o = 0; o < tx->vout.size(); o++) {
	if (view.HaveCoin(COutPoint(tx->GetId(), o))) {
	LogPrintf("ERROR: ConnectBlock(): tried to overwrite "
	"transaction\n");
	return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	"bad-txns-BIP30");
	}
	}
	}
	}

	// Start enforcing BIP68 (sequence locks).
	int nLockTimeFlags = 0;
	if (pindex->nHeight >= consensusParams.CSVHeight) {
	nLockTimeFlags \|= LOCKTIME_VERIFY_SEQUENCE;
	}

	const uint32_t flags =
	GetNextBlockScriptFlags(consensusParams, pindex->pprev);

	int64_t nTime2 = GetTimeMicros();
	nTimeForks += nTime2 - nTime1;
	LogPrint(BCLog::BENCH, " - Fork checks: %.2fms [%.2fs (%.2fms/blk)]\n",
	MILLI * (nTime2 - nTime1), nTimeForks * MICRO,
	nTimeForks * MILLI / nBlocksTotal);

	std::vector<int> prevheights;
	Amount nFees = Amount::zero();
	int nInputs = 0;

	// Limit the total executed signature operations in the block, a consensus
	// rule. Tracking during the CPU-consuming part (validation of uncached
	// inputs) is per-input atomic and validation in each thread stops very
	// quickly after the limit is exceeded, so an adversary cannot cause us to
	// exceed the limit by much at all.
	CheckInputsLimiter nSigChecksBlockLimiter(
	GetMaxBlockSigChecksCount(options.getExcessiveBlockSize()));

	std::vector<TxSigCheckLimiter> nSigChecksTxLimiters;
	nSigChecksTxLimiters.resize(block.vtx.size() - 1);

	CBlockUndo blockundo;
	blockundo.vtxundo.resize(block.vtx.size() - 1);

	CCheckQueueControl<CScriptCheck> control(fScriptChecks ? &scriptcheckqueue
	: nullptr);

	// Add all outputs
	try {
	for (const auto &ptx : block.vtx) {
	AddCoins(view, *ptx, pindex->nHeight);
	}
	} catch (const std::logic_error &e) {
	// This error will be thrown from AddCoin if we try to connect a block
	// containing duplicate transactions. Such a thing should normally be
	// caught early nowadays (due to ContextualCheckBlock's CTOR
	// enforcement) however some edge cases can escape that:
	// - ContextualCheckBlock does not get re-run after saving the block to
	// disk, and older versions may have saved a weird block.
	// - its checks are not applied to pre-CTOR chains, which we might visit
	// with checkpointing off.
	LogPrintf("ERROR: ConnectBlock(): tried to overwrite transaction\n");
	return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	"tx-duplicate");
	}

	size_t txIndex = 0;
	for (const auto &ptx : block.vtx) {
	const CTransaction &tx = *ptx;
	const bool isCoinBase = tx.IsCoinBase();
	nInputs += tx.vin.size();

	{
	Amount txfee = Amount::zero();
	TxValidationState tx_state;
	if (!isCoinBase &&
	!Consensus::CheckTxInputs(tx, tx_state, view, pindex->nHeight,
	txfee)) {
	// Any transaction validation failure in ConnectBlock is a block
	// consensus failure.
	state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	tx_state.GetRejectReason(),
	tx_state.GetDebugMessage());

	return error("%s: Consensus::CheckTxInputs: %s, %s", __func__,
	tx.GetId().ToString(), state.ToString());
	}
	nFees += txfee;
	}

	if (!MoneyRange(nFees)) {
	LogPrintf("ERROR: %s: accumulated fee in the block out of range.\n",
	__func__);
	return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	"bad-txns-accumulated-fee-outofrange");
	}

	// The following checks do not apply to the coinbase.
	if (isCoinBase) {
	continue;
	}

	// 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.AccessCoin(tx.vin[j].prevout).GetHeight();
	}

	if (!SequenceLocks(tx, nLockTimeFlags, prevheights, *pindex)) {
	LogPrintf("ERROR: %s: contains a non-BIP68-final transaction\n",
	__func__);
	return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	"bad-txns-nonfinal");
	}

	// Don't cache results if we're actually connecting blocks (still
	// consult the cache, though).
	bool fCacheResults = fJustCheck;

	const bool fEnforceSigCheck = flags & SCRIPT_ENFORCE_SIGCHECKS;
	if (!fEnforceSigCheck) {
	// Historically, there has been transactions with a very high
	// sigcheck count, so we need to disable this check for such
	// transactions.
	nSigChecksTxLimiters[txIndex] = TxSigCheckLimiter::getDisabled();
	}

	std::vector<CScriptCheck> vChecks;
	// nSigChecksRet may be accurate (found in cache) or 0 (checks were
	// deferred into vChecks).
	int nSigChecksRet;
	TxValidationState tx_state;
	if (fScriptChecks &&
	!CheckInputScripts(tx, tx_state, view, flags, fCacheResults,
	fCacheResults, PrecomputedTransactionData(tx),
	nSigChecksRet, nSigChecksTxLimiters[txIndex],
	&nSigChecksBlockLimiter, &vChecks)) {
	// Any transaction validation failure in ConnectBlock is a block
	// consensus failure
	state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	tx_state.GetRejectReason(),
	tx_state.GetDebugMessage());
	return error(
	"ConnectBlock(): CheckInputScripts on %s failed with %s",
	tx.GetId().ToString(), state.ToString());
	}

	control.Add(vChecks);

	// Note: this must execute in the same iteration as CheckTxInputs (not
	// in a separate loop) in order to detect double spends. However,
	// this does not prevent double-spending by duplicated transaction
	// inputs in the same transaction (cf. CVE-2018-17144) -- that check is
	// done in CheckBlock (CheckRegularTransaction).
	SpendCoins(view, tx, blockundo.vtxundo.at(txIndex), pindex->nHeight);
	txIndex++;
	}

	int64_t nTime3 = GetTimeMicros();
	nTimeConnect += nTime3 - nTime2;
	LogPrint(BCLog::BENCH,
	" - Connect %u transactions: %.2fms (%.3fms/tx, %.3fms/txin) "
	"[%.2fs (%.2fms/blk)]\n",
	(unsigned)block.vtx.size(), MILLI * (nTime3 - nTime2),
	MILLI * (nTime3 - nTime2) / block.vtx.size(),
	nInputs <= 1 ? 0 : MILLI * (nTime3 - nTime2) / (nInputs - 1),
	nTimeConnect * MICRO, nTimeConnect * MILLI / nBlocksTotal);

	Amount blockReward =
	nFees + GetBlockSubsidy(pindex->nHeight, consensusParams);
	if (block.vtx[0]->GetValueOut() > blockReward) {
	LogPrintf("ERROR: ConnectBlock(): coinbase pays too much (actual=%d vs "
	"limit=%d)\n",
	block.vtx[0]->GetValueOut(), blockReward);
	return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	"bad-cb-amount");
	}

	const std::vector<CTxDestination> whitelist =
	GetMinerFundWhitelist(consensusParams, pindex->pprev);
	if (!whitelist.empty()) {
	const Amount required = GetMinerFundAmount(blockReward);

	for (auto &o : block.vtx[0]->vout) {
	if (o.nValue < required) {
	// This output doesn't qualify because its amount is too low.
	continue;
	}

	CTxDestination address;
	if (!ExtractDestination(o.scriptPubKey, address)) {
	// Cannot decode address.
	continue;
	}

	if (std::find(whitelist.begin(), whitelist.end(), address) !=
	whitelist.end()) {
	goto MinerFundSuccess;
	}
	}

	// We did not find an output that match the miner fund requirements.
	return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	"bad-cb-minerfund");
	}

	MinerFundSuccess:

	if (!control.Wait()) {
	return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	"blk-bad-inputs", "parallel script check failed");
	}

	int64_t nTime4 = GetTimeMicros();
	nTimeVerify += nTime4 - nTime2;
	LogPrint(
	BCLog::BENCH,
	" - Verify %u txins: %.2fms (%.3fms/txin) [%.2fs (%.2fms/blk)]\n",
	nInputs - 1, MILLI * (nTime4 - nTime2),
	nInputs <= 1 ? 0 : MILLI * (nTime4 - nTime2) / (nInputs - 1),
	nTimeVerify * MICRO, nTimeVerify * MILLI / nBlocksTotal);

	if (fJustCheck) {
	return true;
	}

	if (!WriteUndoDataForBlock(blockundo, state, pindex, params)) {
	return false;
	}

	if (!pindex->IsValid(BlockValidity::SCRIPTS)) {
	pindex->RaiseValidity(BlockValidity::SCRIPTS);
	setDirtyBlockIndex.insert(pindex);
	}

	assert(pindex->phashBlock);
	// add this block to the view's block chain
	view.SetBestBlock(pindex->GetBlockHash());

	int64_t nTime5 = GetTimeMicros();
	nTimeIndex += nTime5 - nTime4;
	LogPrint(BCLog::BENCH, " - Index writing: %.2fms [%.2fs (%.2fms/blk)]\n",
	MILLI * (nTime5 - nTime4), nTimeIndex * MICRO,
	nTimeIndex * MILLI / nBlocksTotal);

	int64_t nTime6 = GetTimeMicros();
	nTimeCallbacks += nTime6 - nTime5;
	LogPrint(BCLog::BENCH, " - Callbacks: %.2fms [%.2fs (%.2fms/blk)]\n",
	MILLI * (nTime6 - nTime5), nTimeCallbacks * MICRO,
	nTimeCallbacks * MILLI / nBlocksTotal);

	return true;
	}

	CoinsCacheSizeState
	CChainState::GetCoinsCacheSizeState(const CTxMemPool *tx_pool) {
	return this->GetCoinsCacheSizeState(
	tx_pool, m_coinstip_cache_size_bytes,
	gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000);
	}

	CoinsCacheSizeState
	CChainState::GetCoinsCacheSizeState(const CTxMemPool *tx_pool,
	size_t max_coins_cache_size_bytes,
	size_t max_mempool_size_bytes) {
	int64_t nMempoolUsage = tx_pool->DynamicMemoryUsage();
	int64_t cacheSize = CoinsTip().DynamicMemoryUsage();
	int64_t nTotalSpace =
	max_coins_cache_size_bytes +
	std::max<int64_t>(max_mempool_size_bytes - nMempoolUsage, 0);

	//! No need to periodic flush if at least this much space still available.
	static constexpr int64_t MAX_BLOCK_COINSDB_USAGE_BYTES =
	10 * 1024 * 1024; // 10MB
	int64_t large_threshold = std::max(
	(9 * nTotalSpace) / 10, nTotalSpace - MAX_BLOCK_COINSDB_USAGE_BYTES);

	if (cacheSize > nTotalSpace) {
	LogPrintf("Cache size (%s) exceeds total space (%s)\n", cacheSize,
	nTotalSpace);
	return CoinsCacheSizeState::CRITICAL;
	} else if (cacheSize > large_threshold) {
	return CoinsCacheSizeState::LARGE;
	}
	return CoinsCacheSizeState::OK;
	}

	bool CChainState::FlushStateToDisk(const CChainParams &chainparams,
	BlockValidationState &state,
	FlushStateMode mode,
	int nManualPruneHeight) {
	LOCK(cs_main);
	assert(this->CanFlushToDisk());
	static std::chrono::microseconds nLastWrite{0};
	static std::chrono::microseconds nLastFlush{0};
	std::set<int> setFilesToPrune;
	bool full_flush_completed = false;

	const size_t coins_count = CoinsTip().GetCacheSize();
	const size_t coins_mem_usage = CoinsTip().DynamicMemoryUsage();

	try {
	{
	bool fFlushForPrune = false;
	bool fDoFullFlush = false;
	CoinsCacheSizeState cache_state =
	GetCoinsCacheSizeState(&m_mempool);
	LOCK(cs_LastBlockFile);
	if (fPruneMode && (fCheckForPruning \|\| nManualPruneHeight > 0) &&
	!fReindex) {
	if (nManualPruneHeight > 0) {
	LOG_TIME_MILLIS_WITH_CATEGORY(
	"find files to prune (manual)", BCLog::BENCH);
	m_blockman.FindFilesToPruneManual(
	setFilesToPrune, nManualPruneHeight, m_chain.Height());
	} else {
	LOG_TIME_MILLIS_WITH_CATEGORY("find files to prune",
	BCLog::BENCH);
	m_blockman.FindFilesToPrune(
	setFilesToPrune, chainparams.PruneAfterHeight(),
	m_chain.Height(), IsInitialBlockDownload());
	fCheckForPruning = false;
	}
	if (!setFilesToPrune.empty()) {
	fFlushForPrune = true;
	if (!fHavePruned) {
	pblocktree->WriteFlag("prunedblockfiles", true);
	fHavePruned = true;
	}
	}
	}
	const auto nNow = GetTime<std::chrono::microseconds>();
	// Avoid writing/flushing immediately after startup.
	if (nLastWrite.count() == 0) {
	nLastWrite = nNow;
	}
	if (nLastFlush.count() == 0) {
	nLastFlush = nNow;
	}
	// The cache is large and we're within 10% and 10 MiB of the limit,
	// but we have time now (not in the middle of a block processing).
	bool fCacheLarge = mode == FlushStateMode::PERIODIC &&
	cache_state >= CoinsCacheSizeState::LARGE;
	// The cache is over the limit, we have to write now.
	bool fCacheCritical = mode == FlushStateMode::IF_NEEDED &&
	cache_state >= CoinsCacheSizeState::CRITICAL;
	// 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 == FlushStateMode::PERIODIC &&
	nNow > nLastWrite + DATABASE_WRITE_INTERVAL;
	// It's been very long since we flushed the cache. Do this
	// infrequently, to optimize cache usage.
	bool fPeriodicFlush = mode == FlushStateMode::PERIODIC &&
	nNow > nLastFlush + DATABASE_FLUSH_INTERVAL;
	// Combine all conditions that result in a full cache flush.
	fDoFullFlush = (mode == FlushStateMode::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(gArgs.GetBlocksDirPath())) {
	return AbortNode(state, "Disk space is too low!",
	_("Disk space is too low!"));
	}

	{
	LOG_TIME_MILLIS_WITH_CATEGORY(
	"write block and undo data to disk", BCLog::BENCH);

	// 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).
	{
	LOG_TIME_MILLIS_WITH_CATEGORY("write block index to disk",
	BCLog::BENCH);

	std::vector<std::pair<int, const CBlockFileInfo *>> vFiles;
	vFiles.reserve(setDirtyFileInfo.size());
	for (int i : setDirtyFileInfo) {
	vFiles.push_back(std::make_pair(i, &vinfoBlockFile[i]));
	}

	setDirtyFileInfo.clear();

	std::vector<const CBlockIndex *> vBlocks;
	vBlocks.reserve(setDirtyBlockIndex.size());
	for (const CBlockIndex *cbi : setDirtyBlockIndex) {
	vBlocks.push_back(cbi);
	}

	setDirtyBlockIndex.clear();

	if (!pblocktree->WriteBatchSync(vFiles, nLastBlockFile,
	vBlocks)) {
	return AbortNode(
	state, "Failed to write to block index database");
	}
	}

	// Finally remove any pruned files
	if (fFlushForPrune) {
	LOG_TIME_MILLIS_WITH_CATEGORY("unlink pruned files",
	BCLog::BENCH);

	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 && !CoinsTip().GetBestBlock().IsNull()) {
	LOG_TIME_SECONDS(
	strprintf("write coins cache to disk (%d coins, %.2fkB)",
	coins_count, coins_mem_usage / 1000));

	// Typical Coin structures on disk are around 48 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(GetDataDir(),
	48 * 2 * 2 * CoinsTip().GetCacheSize())) {
	return AbortNode(state, "Disk space is too low!",
	_("Disk space is too low!"));
	}

	// Flush the chainstate (which may refer to block index
	// entries).
	if (!CoinsTip().Flush()) {
	return AbortNode(state, "Failed to write to coin database");
	}
	nLastFlush = nNow;
	full_flush_completed = true;
	}
	}

	if (full_flush_completed) {
	// Update best block in wallet (so we can detect restored wallets).
	GetMainSignals().ChainStateFlushed(m_chain.GetLocator());
	}
	} catch (const std::runtime_error &e) {
	return AbortNode(state, std::string("System error while flushing: ") +
	e.what());
	}
	return true;
	}

	void CChainState::ForceFlushStateToDisk() {
	BlockValidationState state;
	const CChainParams &chainparams = Params();
	if (!this->FlushStateToDisk(chainparams, state, FlushStateMode::ALWAYS)) {
	LogPrintf("%s: failed to flush state (%s)\n", __func__,
	state.ToString());
	}
	}

	void CChainState::PruneAndFlush() {
	BlockValidationState state;
	fCheckForPruning = true;
	const CChainParams &chainparams = Params();
	if (!this->FlushStateToDisk(chainparams, state, FlushStateMode::NONE)) {
	LogPrintf("%s: failed to flush state (%s)\n", __func__,
	state.ToString());
	}
	}

	/** Check warning conditions and do some notifications on new chain tip set. */
	static void UpdateTip(CTxMemPool &mempool, const CChainParams &params,
	CBlockIndex *pindexNew)
	EXCLUSIVE_LOCKS_REQUIRED(::cs_main) {
	// New best block
	mempool.AddTransactionsUpdated(1);

	{
	LOCK(g_best_block_mutex);
	g_best_block = pindexNew->GetBlockHash();
	g_best_block_cv.notify_all();
	}

	LogPrintf("%s: new best=%s height=%d version=0x%08x log2_work=%f tx=%ld "
	"date='%s' progress=%f cache=%.1fMiB(%utxo)\n",
	__func__, pindexNew->GetBlockHash().ToString(),
	pindexNew->nHeight, pindexNew->nVersion,
	log(pindexNew->nChainWork.getdouble()) / log(2.0),
	pindexNew->GetChainTxCount(),
	FormatISO8601DateTime(pindexNew->GetBlockTime()),
	GuessVerificationProgress(params.TxData(), pindexNew),
	::ChainstateActive().CoinsTip().DynamicMemoryUsage() *
	(1.0 / (1 << 20)),
	::ChainstateActive().CoinsTip().GetCacheSize());
	}

	/**
	* Disconnect m_chain's tip.
	* After calling, the mempool will be in an inconsistent state, with
	* transactions from disconnected blocks being added to disconnectpool. You
	* should make the mempool consistent again by calling updateMempoolForReorg.
	* with cs_main held.
	*
	* If disconnectpool is nullptr, then no disconnected transactions are added to
	* disconnectpool (note that the caller is responsible for mempool consistency
	* in any case).
	*/
	bool CChainState::DisconnectTip(const CChainParams &params,
	BlockValidationState &state,
	DisconnectedBlockTransactions *disconnectpool) {
	AssertLockHeld(cs_main);
	AssertLockHeld(m_mempool.cs);
	CBlockIndex *pindexDelete = m_chain.Tip();
	const Consensus::Params &consensusParams = params.GetConsensus();

	assert(pindexDelete);

	// Read block from disk.
	std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
	CBlock &block = *pblock;
	if (!ReadBlockFromDisk(block, pindexDelete, consensusParams)) {
	return error("DisconnectTip(): Failed to read block");
	}

	// Apply the block atomically to the chain state.
	int64_t nStart = GetTimeMicros();
	{
	CCoinsViewCache view(&CoinsTip());
	assert(view.GetBestBlock() == pindexDelete->GetBlockHash());
	if (DisconnectBlock(block, pindexDelete, view) !=
	DisconnectResult::OK) {
	return error("DisconnectTip(): DisconnectBlock %s failed",
	pindexDelete->GetBlockHash().ToString());
	}

	bool flushed = view.Flush();
	assert(flushed);
	}

	LogPrint(BCLog::BENCH, "- Disconnect block: %.2fms\n",
	(GetTimeMicros() - nStart) * MILLI);

	// Write the chain state to disk, if necessary.
	if (!FlushStateToDisk(params, state, FlushStateMode::IF_NEEDED)) {
	return false;
	}

	// If this block is deactivating a fork, we move all mempool transactions
	// in front of disconnectpool for reprocessing in a future
	// updateMempoolForReorg call
	if (pindexDelete->pprev != nullptr &&
	GetNextBlockScriptFlags(consensusParams, pindexDelete) !=
	GetNextBlockScriptFlags(consensusParams, pindexDelete->pprev)) {
	LogPrint(BCLog::MEMPOOL,
	"Disconnecting mempool due to rewind of upgrade block\n");
	if (disconnectpool) {
	disconnectpool->importMempool(m_mempool);
	}
	m_mempool.clear();
	}

	if (disconnectpool) {
	disconnectpool->addForBlock(block.vtx, m_mempool);
	}

	// If the tip is finalized, then undo it.
	if (m_finalizedBlockIndex == pindexDelete) {
	m_finalizedBlockIndex = pindexDelete->pprev;
	}

	m_chain.SetTip(pindexDelete->pprev);

	// Update ::ChainActive() and related variables.
	UpdateTip(m_mempool, params, pindexDelete->pprev);
	// Let wallets know transactions went from 1-confirmed to
	// 0-confirmed or conflicted:
	GetMainSignals().BlockDisconnected(pblock, pindexDelete);
	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;

	struct PerBlockConnectTrace {
	CBlockIndex *pindex = nullptr;
	std::shared_ptr<const CBlock> pblock;
	PerBlockConnectTrace() {}
	};

	/**
	* Used to track blocks whose transactions were applied to the UTXO state as a
	* part of a single ActivateBestChainStep call.
	*
	* This class is single-use, once you call GetBlocksConnected() you have to
	* throw it away and make a new one.
	*/
	class ConnectTrace {
	private:
	std::vector<PerBlockConnectTrace> blocksConnected;

	public:
	explicit ConnectTrace() : blocksConnected(1) {}

	void BlockConnected(CBlockIndex *pindex,
	std::shared_ptr<const CBlock> pblock) {
	assert(!blocksConnected.back().pindex);
	assert(pindex);
	assert(pblock);
	blocksConnected.back().pindex = pindex;
	blocksConnected.back().pblock = std::move(pblock);
	blocksConnected.emplace_back();
	}

	std::vector<PerBlockConnectTrace> &GetBlocksConnected() {
	// We always keep one extra block at the end of our list because blocks
	// are added after all the conflicted transactions have been filled in.
	// Thus, the last entry should always be an empty one waiting for the
	// transactions from the next block. We pop the last entry here to make
	// sure the list we return is sane.
	assert(!blocksConnected.back().pindex);
	blocksConnected.pop_back();
	return blocksConnected;
	}
	};

	bool CChainState::MarkBlockAsFinal(BlockValidationState &state,
	const CBlockIndex *pindex) {
	AssertLockHeld(cs_main);
	if (pindex->nStatus.isInvalid()) {
	// We try to finalize an invalid block.
	LogPrintf("ERROR: %s: Trying to finalize invalid block %s\n", __func__,
	pindex->GetBlockHash().ToString());
	return state.Invalid(BlockValidationResult::BLOCK_CACHED_INVALID,
	"finalize-invalid-block");
	}

	// Check that the request is consistent with current finalization.
	if (m_finalizedBlockIndex &&
	!AreOnTheSameFork(pindex, m_finalizedBlockIndex)) {
	LogPrintf("ERROR: %s: Trying to finalize block %s which conflicts with "
	"already finalized block\n",
	__func__, pindex->GetBlockHash().ToString());
	return state.Invalid(BlockValidationResult::BLOCK_FINALIZATION,
	"bad-fork-prior-finalized");
	}

	if (IsBlockFinalized(pindex)) {
	// The block is already finalized.
	return true;
	}

	// We have a new block to finalize.
	m_finalizedBlockIndex = pindex;
	return true;
	}

	static const CBlockIndex FindBlockToFinalize(CBlockIndex pindexNew)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
	AssertLockHeld(cs_main);

	const int32_t maxreorgdepth =
	gArgs.GetArg("-maxreorgdepth", DEFAULT_MAX_REORG_DEPTH);

	const int64_t finalizationdelay =
	gArgs.GetArg("-finalizationdelay", DEFAULT_MIN_FINALIZATION_DELAY);

	// Find our candidate.
	// If maxreorgdepth is < 0 pindex will be null and auto finalization
	// disabled
	const CBlockIndex *pindex =
	pindexNew->GetAncestor(pindexNew->nHeight - maxreorgdepth);

	int64_t now = GetTime();

	// If the finalization delay is not expired since the startup time,
	// finalization should be avoided. Header receive time is not saved to disk
	// and so cannot be anterior to startup time.
	if (now < (GetStartupTime() + finalizationdelay)) {
	return nullptr;
	}

	// While our candidate is not eligible (finalization delay not expired), try
	// the previous one.
	while (pindex && (pindex != ::ChainstateActive().GetFinalizedBlock())) {
	// Check that the block to finalize is known for a long enough time.
	// This test will ensure that an attacker could not cause a block to
	// finalize by forking the chain with a depth > maxreorgdepth.
	// If the block is loaded from disk, header receive time is 0 and the
	// block will be finalized. This is safe because the delay since the
	// node startup is already expired.
	auto headerReceivedTime = pindex->GetHeaderReceivedTime();

	// If finalization delay is <= 0, finalization always occurs immediately
	if (now >= (headerReceivedTime + finalizationdelay)) {
	return pindex;
	}

	pindex = pindex->pprev;
	}

	return nullptr;
	}

	/**
	* Connect a new block to m_chain. 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.
	*/
	bool CChainState::ConnectTip(const Config &config, BlockValidationState &state,
	CBlockIndex *pindexNew,
	const std::shared_ptr<const CBlock> &pblock,
	ConnectTrace &connectTrace,
	DisconnectedBlockTransactions &disconnectpool) {
	AssertLockHeld(cs_main);
	AssertLockHeld(m_mempool.cs);

	const CChainParams &params = config.GetChainParams();
	const Consensus::Params &consensusParams = params.GetConsensus();

	assert(pindexNew->pprev == m_chain.Tip());
	// Read block from disk.
	int64_t nTime1 = GetTimeMicros();
	std::shared_ptr<const CBlock> pthisBlock;
	if (!pblock) {
	std::shared_ptr<CBlock> pblockNew = std::make_shared<CBlock>();
	if (!ReadBlockFromDisk(*pblockNew, pindexNew, consensusParams)) {
	return AbortNode(state, "Failed to read block");
	}
	pthisBlock = pblockNew;
	} else {
	pthisBlock = pblock;
	}

	const CBlock &blockConnecting = *pthisBlock;

	// Apply the block atomically to the chain state.
	int64_t nTime2 = GetTimeMicros();
	nTimeReadFromDisk += nTime2 - nTime1;
	int64_t nTime3;
	LogPrint(BCLog::BENCH, " - Load block from disk: %.2fms [%.2fs]\n",
	(nTime2 - nTime1) * MILLI, nTimeReadFromDisk * MICRO);
	{
	CCoinsViewCache view(&CoinsTip());
	bool rv = ConnectBlock(blockConnecting, state, pindexNew, view, params,
	BlockValidationOptions(config));
	GetMainSignals().BlockChecked(blockConnecting, state);
	if (!rv) {
	if (state.IsInvalid()) {
	InvalidBlockFound(pindexNew, state);
	}

	return error("%s: ConnectBlock %s failed, %s", __func__,
	pindexNew->GetBlockHash().ToString(),
	state.ToString());
	}

	// Update the finalized block.
	const CBlockIndex *pindexToFinalize = FindBlockToFinalize(pindexNew);
	if (pindexToFinalize && !MarkBlockAsFinal(state, pindexToFinalize)) {
	return error("ConnectTip(): MarkBlockAsFinal %s failed (%s)",
	pindexNew->GetBlockHash().ToString(),
	state.ToString());
	}

	nTime3 = GetTimeMicros();
	nTimeConnectTotal += nTime3 - nTime2;
	assert(nBlocksTotal > 0);
	LogPrint(BCLog::BENCH,
	" - Connect total: %.2fms [%.2fs (%.2fms/blk)]\n",
	(nTime3 - nTime2) * MILLI, nTimeConnectTotal * MICRO,
	nTimeConnectTotal * MILLI / nBlocksTotal);
	bool flushed = view.Flush();
	assert(flushed);
	}

	int64_t nTime4 = GetTimeMicros();
	nTimeFlush += nTime4 - nTime3;
	LogPrint(BCLog::BENCH, " - Flush: %.2fms [%.2fs (%.2fms/blk)]\n",
	(nTime4 - nTime3) * MILLI, nTimeFlush * MICRO,
	nTimeFlush * MILLI / nBlocksTotal);

	// Write the chain state to disk, if necessary.
	if (!FlushStateToDisk(config.GetChainParams(), state,
	FlushStateMode::IF_NEEDED)) {
	return false;
	}

	int64_t nTime5 = GetTimeMicros();
	nTimeChainState += nTime5 - nTime4;
	LogPrint(BCLog::BENCH,
	" - Writing chainstate: %.2fms [%.2fs (%.2fms/blk)]\n",
	(nTime5 - nTime4) * MILLI, nTimeChainState * MICRO,
	nTimeChainState * MILLI / nBlocksTotal);

	// Remove conflicting transactions from the mempool.;
	m_mempool.removeForBlock(blockConnecting.vtx, pindexNew->nHeight);
	disconnectpool.removeForBlock(blockConnecting.vtx);

	// If this block is activating a fork, we move all mempool transactions
	// in front of disconnectpool for reprocessing in a future
	// updateMempoolForReorg call
	if (pindexNew->pprev != nullptr &&
	GetNextBlockScriptFlags(consensusParams, pindexNew) !=
	GetNextBlockScriptFlags(consensusParams, pindexNew->pprev)) {
	LogPrint(BCLog::MEMPOOL,
	"Disconnecting mempool due to acceptance of upgrade block\n");
	disconnectpool.importMempool(m_mempool);
	}

	// Update m_chain & related variables.
	m_chain.SetTip(pindexNew);
	UpdateTip(m_mempool, params, pindexNew);

	int64_t nTime6 = GetTimeMicros();
	nTimePostConnect += nTime6 - nTime5;
	nTimeTotal += nTime6 - nTime1;
	LogPrint(BCLog::BENCH,
	" - Connect postprocess: %.2fms [%.2fs (%.2fms/blk)]\n",
	(nTime6 - nTime5) * MILLI, nTimePostConnect * MICRO,
	nTimePostConnect * MILLI / nBlocksTotal);
	LogPrint(BCLog::BENCH, "- Connect block: %.2fms [%.2fs (%.2fms/blk)]\n",
	(nTime6 - nTime1) * MILLI, nTimeTotal * MICRO,
	nTimeTotal * MILLI / nBlocksTotal);

	connectTrace.BlockConnected(pindexNew, std::move(pthisBlock));
	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).
	*/
	CBlockIndex *CChainState::FindMostWorkChain() {
	AssertLockHeld(cs_main);
	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;
	}

	// If this block will cause a finalized block to be reorged, then we
	// mark it as invalid.
	if (m_finalizedBlockIndex &&
	!AreOnTheSameFork(pindexNew, m_finalizedBlockIndex)) {
	LogPrintf("Mark block %s invalid because it forks prior to the "
	"finalization point %d.\n",
	pindexNew->GetBlockHash().ToString(),
	m_finalizedBlockIndex->nHeight);
	pindexNew->nStatus = pindexNew->nStatus.withFailed();
	InvalidChainFound(pindexNew);
	}

	const bool fAvalancheEnabled = isAvalancheEnabled(gArgs);
	const bool fAutoUnpark =
	gArgs.GetBoolArg("-automaticunparking", !fAvalancheEnabled);

	const CBlockIndex *pindexFork = m_chain.FindFork(pindexNew);

	// 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 hasValidAncestor = true;
	while (hasValidAncestor && pindexTest && pindexTest != pindexFork) {
	assert(pindexTest->HaveTxsDownloaded() \|\| pindexTest->nHeight == 0);

	// If this is a parked chain, but it has enough PoW, clear the park
	// state.
	bool fParkedChain = pindexTest->nStatus.isOnParkedChain();
	if (fAutoUnpark && fParkedChain) {
	const CBlockIndex *pindexTip = m_chain.Tip();

	// During initialization, pindexTip and/or pindexFork may be
	// null. In this case, we just ignore the fact that the chain is
	// parked.
	if (!pindexTip \|\| !pindexFork) {
	UnparkBlock(pindexTest);
	continue;
	}

	// A parked chain can be unparked if it has twice as much PoW
	// accumulated as the main chain has since the fork block.
	CBlockIndex const *pindexExtraPow = pindexTip;
	arith_uint256 requiredWork = pindexTip->nChainWork;
	switch (pindexTip->nHeight - pindexFork->nHeight) {
	// Limit the penality for depth 1, 2 and 3 to half a block
	// worth of work to ensure we don't fork accidentally.
	case 3:
	case 2:
	pindexExtraPow = pindexExtraPow->pprev;
	// FALLTHROUGH
	case 1: {
	const arith_uint256 deltaWork =
	pindexExtraPow->nChainWork - pindexFork->nChainWork;
	requiredWork += (deltaWork >> 1);
	break;
	}
	default:
	requiredWork +=
	pindexExtraPow->nChainWork - pindexFork->nChainWork;
	break;
	}

	if (pindexNew->nChainWork > requiredWork) {
	// We have enough, clear the parked state.
	LogPrintf("Unpark chain up to block %s as it has "
	"accumulated enough PoW.\n",
	pindexNew->GetBlockHash().ToString());
	fParkedChain = false;
	UnparkBlock(pindexTest);
	}
	}

	// 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 fInvalidChain = pindexTest->nStatus.isInvalid();
	bool fMissingData = !pindexTest->nStatus.hasData();
	if (!(fInvalidChain \|\| fParkedChain \|\| fMissingData)) {
	// The current block is acceptable, move to the parent, up to
	// the fork point.
	pindexTest = pindexTest->pprev;
	continue;
	}

	// Candidate chain is not usable (either invalid or parked or
	// missing data)
	hasValidAncestor = false;
	setBlockIndexCandidates.erase(pindexTest);

	if (fInvalidChain &&
	(pindexBestInvalid == nullptr \|\|
	pindexNew->nChainWork > pindexBestInvalid->nChainWork)) {
	pindexBestInvalid = pindexNew;
	}

	if (fParkedChain &&
	(pindexBestParked == nullptr \|\|
	pindexNew->nChainWork > pindexBestParked->nChainWork)) {
	pindexBestParked = pindexNew;
	}

	LogPrintf("Considered switching to better tip %s but that chain "
	"contains a%s%s%s block.\n",
	pindexNew->GetBlockHash().ToString(),
	fInvalidChain ? "n invalid" : "",
	fParkedChain ? " parked" : "",
	fMissingData ? " missing-data" : "");

	CBlockIndex *pindexFailed = pindexNew;
	// Remove the entire chain from the set.
	while (pindexTest != pindexFailed) {
	if (fInvalidChain \|\| fParkedChain) {
	pindexFailed->nStatus =
	pindexFailed->nStatus.withFailedParent(fInvalidChain)
	.withParkedParent(fParkedChain);
	} else if (fMissingData) {
	// If we're missing data, then add back to
	// m_blocks_unlinked, so that if the block arrives in the
	// future we can try adding to setBlockIndexCandidates
	// again.
	m_blockman.m_blocks_unlinked.insert(
	std::make_pair(pindexFailed->pprev, pindexFailed));
	}
	setBlockIndexCandidates.erase(pindexFailed);
	pindexFailed = pindexFailed->pprev;
	}

	if (fInvalidChain \|\| fParkedChain) {
	// We discovered a new chain tip that is either parked or
	// invalid, we may want to warn.
	CheckForkWarningConditionsOnNewFork(pindexNew);
	}
	}

	if (fAvalancheEnabled && g_avalanche) {
	g_avalanche->addBlockToReconcile(pindexNew);
	}

	// We found a candidate that has valid ancestors. This is our guy.
	if (hasValidAncestor) {
	return pindexNew;
	}
	} while (true);
	}

	/**
	* Delete all entries in setBlockIndexCandidates that are worse than the current
	* tip.
	*/
	void CChainState::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.
	auto it = setBlockIndexCandidates.begin();
	while (it != setBlockIndexCandidates.end() &&
	setBlockIndexCandidates.value_comp()(*it, m_chain.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.
	*
	* @returns true unless a system error occurred
	*/
	bool CChainState::ActivateBestChainStep(
	const Config &config, BlockValidationState &state,
	CBlockIndex *pindexMostWork, const std::shared_ptr<const CBlock> &pblock,
	bool &fInvalidFound, ConnectTrace &connectTrace) {
	AssertLockHeld(cs_main);
	AssertLockHeld(m_mempool.cs);

	const CBlockIndex *pindexOldTip = m_chain.Tip();
	const CBlockIndex *pindexFork = m_chain.FindFork(pindexMostWork);

	// Disconnect active blocks which are no longer in the best chain.
	bool fBlocksDisconnected = false;
	DisconnectedBlockTransactions disconnectpool;
	while (m_chain.Tip() && m_chain.Tip() != pindexFork) {
	if (!DisconnectTip(config.GetChainParams(), state, &disconnectpool)) {
	// This is likely a fatal error, but keep the mempool consistent,
	// just in case. Only remove from the mempool in this case.
	disconnectpool.updateMempoolForReorg(config, false, m_mempool);

	// If we're unable to disconnect a block during normal operation,
	// then that is a failure of our local system -- we should abort
	// rather than stay on a less work chain.
	AbortNode(state,
	"Failed to disconnect block; see debug.log for details");
	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 : reverse_iterate(vpindexToConnect)) {
	if (!ConnectTip(config, state, pindexConnect,
	pindexConnect == pindexMostWork
	? pblock
	: std::shared_ptr<const CBlock>(),
	connectTrace, disconnectpool)) {
	if (state.IsInvalid()) {
	// The block violates a consensus rule.
	if (state.GetResult() !=
	BlockValidationResult::BLOCK_MUTATED) {
	InvalidChainFound(vpindexToConnect.back());
	}
	state = BlockValidationState();
	fInvalidFound = true;
	fContinue = false;
	break;
	}

	// A system error occurred (disk space, database error, ...).
	// Make the mempool consistent with the current tip, just in
	// case any observers try to use it before shutdown.
	disconnectpool.updateMempoolForReorg(config, false, m_mempool);
	return false;
	} else {
	PruneBlockIndexCandidates();
	if (!pindexOldTip \|\|
	m_chain.Tip()->nChainWork > pindexOldTip->nChainWork) {
	// We're in a better position than we were. Return
	// temporarily to release the lock.
	fContinue = false;
	break;
	}
	}
	}
	}

	if (fBlocksDisconnected \|\| !disconnectpool.isEmpty()) {
	// If any blocks were disconnected, we need to update the mempool even
	// if disconnectpool is empty. The disconnectpool may also be non-empty
	// if the mempool was imported due to new validation rules being in
	// effect.
	LogPrint(BCLog::MEMPOOL, "Updating mempool due to reorganization or "
	"rules upgrade/downgrade\n");
	disconnectpool.updateMempoolForReorg(config, true, m_mempool);
	}

	m_mempool.check(&CoinsTip());

	// Callbacks/notifications for a new best chain.
	if (fInvalidFound) {
	CheckForkWarningConditionsOnNewFork(pindexMostWork);
	} else {
	CheckForkWarningConditions();
	}

	return true;
	}

	static SynchronizationState GetSynchronizationState(bool init) {
	if (!init) {
	return SynchronizationState::POST_INIT;
	}
	if (::fReindex) {
	return SynchronizationState::INIT_REINDEX;
	}
	return SynchronizationState::INIT_DOWNLOAD;
	}

	static bool NotifyHeaderTip() LOCKS_EXCLUDED(cs_main) {
	bool fNotify = false;
	bool fInitialBlockDownload = false;
	static CBlockIndex *pindexHeaderOld = nullptr;
	CBlockIndex *pindexHeader = nullptr;
	{
	LOCK(cs_main);
	pindexHeader = pindexBestHeader;

	if (pindexHeader != pindexHeaderOld) {
	fNotify = true;
	fInitialBlockDownload =
	::ChainstateActive().IsInitialBlockDownload();
	pindexHeaderOld = pindexHeader;
	}
	}

	// Send block tip changed notifications without cs_main
	if (fNotify) {
	uiInterface.NotifyHeaderTip(
	GetSynchronizationState(fInitialBlockDownload), pindexHeader);
	}
	return fNotify;
	}

	static void LimitValidationInterfaceQueue() LOCKS_EXCLUDED(cs_main) {
	AssertLockNotHeld(cs_main);

	if (GetMainSignals().CallbacksPending() > 10) {
	SyncWithValidationInterfaceQueue();
	}
	}

	bool CChainState::ActivateBestChain(const Config &config,
	BlockValidationState &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!
	AssertLockNotHeld(cs_main);

	const CChainParams &params = config.GetChainParams();

	// ABC maintains a fair degree of expensive-to-calculate internal state
	// because this function periodically releases cs_main so that it does not
	// lock up other threads for too long during large connects - and to allow
	// for e.g. the callback queue to drain we use m_cs_chainstate to enforce
	// mutual exclusion so that only one caller may execute this function at a
	// time
	LOCK(m_cs_chainstate);

	CBlockIndex *pindexMostWork = nullptr;
	CBlockIndex *pindexNewTip = nullptr;
	int nStopAtHeight = gArgs.GetArg("-stopatheight", DEFAULT_STOPATHEIGHT);
	do {
	// Block until the validation queue drains. This should largely
	// never happen in normal operation, however may happen during
	// reindex, causing memory blowup if we run too far ahead.
	// Note that if a validationinterface callback ends up calling
	// ActivateBestChain this may lead to a deadlock! We should
	// probably have a DEBUG_LOCKORDER test for this in the future.
	LimitValidationInterfaceQueue();

	{
	LOCK(cs_main);
	// Lock transaction pool for at least as long as it takes for
	// connectTrace to be consumed
	LOCK(m_mempool.cs);
	CBlockIndex *starting_tip = m_chain.Tip();
	bool blocks_connected = false;
	do {
	// We absolutely may not unlock cs_main until we've made forward
	// progress (with the exception of shutdown due to hardware
	// issues, low disk space, etc).

	// Destructed before cs_main is unlocked
	ConnectTrace connectTrace;

	if (pindexMostWork == nullptr) {
	pindexMostWork = FindMostWorkChain();
	}

	// Whether we have anything to do at all.
	if (pindexMostWork == nullptr \|\|
	pindexMostWork == m_chain.Tip()) {
	break;
	}

	bool fInvalidFound = false;
	std::shared_ptr<const CBlock> nullBlockPtr;
	if (!ActivateBestChainStep(
	config, state, pindexMostWork,
	pblock && pblock->GetHash() ==
	pindexMostWork->GetBlockHash()
	? pblock
	: nullBlockPtr,
	fInvalidFound, connectTrace)) {
	// A system error occurred
	return false;
	}
	blocks_connected = true;

	if (fInvalidFound) {
	// Wipe cache, we may need another branch now.
	pindexMostWork = nullptr;
	}

	pindexNewTip = m_chain.Tip();
	for (const PerBlockConnectTrace &trace :
	connectTrace.GetBlocksConnected()) {
	assert(trace.pblock && trace.pindex);
	GetMainSignals().BlockConnected(trace.pblock, trace.pindex);
	}
	} while (!m_chain.Tip() \|\|
	(starting_tip && CBlockIndexWorkComparator()(
	m_chain.Tip(), starting_tip)));

	// Check the index once we're done with the above loop, since
	// we're going to release cs_main soon. If the index is in a bad
	// state now, then it's better to know immediately rather than
	// randomly have it cause a problem in a race.
	CheckBlockIndex(params.GetConsensus());

	if (!blocks_connected) {
	return true;
	}

	const CBlockIndex *pindexFork = m_chain.FindFork(starting_tip);
	bool fInitialDownload = IsInitialBlockDownload();

	// Notify external listeners about the new tip.
	// Enqueue while holding cs_main to ensure that UpdatedBlockTip is
	// called in the order in which blocks are connected
	if (pindexFork != pindexNewTip) {
	// Notify ValidationInterface subscribers
	GetMainSignals().UpdatedBlockTip(pindexNewTip, pindexFork,
	fInitialDownload);

	// Always notify the UI if a new block tip was connected
	uiInterface.NotifyBlockTip(
	GetSynchronizationState(fInitialDownload), pindexNewTip);
	}
	}
	// When we reach this point, we switched to a new tip (stored in
	// pindexNewTip).

	if (nStopAtHeight && pindexNewTip &&
	pindexNewTip->nHeight >= nStopAtHeight) {
	StartShutdown();
	}

	// We check shutdown only after giving ActivateBestChainStep a chance to
	// run once so that we never shutdown before connecting the genesis
	// block during LoadChainTip(). Previously this caused an assert()
	// failure during shutdown in such cases as the UTXO DB flushing checks
	// that the best block hash is non-null.
	if (ShutdownRequested()) {
	break;
	}
	} while (pindexNewTip != pindexMostWork);

	// Write changes periodically to disk, after relay.
	if (!FlushStateToDisk(params, state, FlushStateMode::PERIODIC)) {
	return false;
	}

	return true;
	}

	bool ActivateBestChain(const Config &config, BlockValidationState &state,
	std::shared_ptr<const CBlock> pblock) {
	return ::ChainstateActive().ActivateBestChain(config, state,
	std::move(pblock));
	}

	bool CChainState::PreciousBlock(const Config &config,
	BlockValidationState &state,
	CBlockIndex *pindex) {
	{
	LOCK(cs_main);
	if (pindex->nChainWork < m_chain.Tip()->nChainWork) {
	// Nothing to do, this block is not at the tip.
	return true;
	}

	if (m_chain.Tip()->nChainWork > nLastPreciousChainwork) {
	// The chain has been extended since the last call, reset the
	// counter.
	nBlockReverseSequenceId = -1;
	}

	nLastPreciousChainwork = m_chain.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--;
	}

	// In case this was parked, unpark it.
	UnparkBlock(pindex);

	// Make sure it is added to the candidate list if appropriate.
	if (pindex->IsValid(BlockValidity::TRANSACTIONS) &&
	pindex->HaveTxsDownloaded()) {
	setBlockIndexCandidates.insert(pindex);
	PruneBlockIndexCandidates();
	}
	}

	return ActivateBestChain(config, state);
	}

	bool PreciousBlock(const Config &config, BlockValidationState &state,
	CBlockIndex *pindex) {
	return ::ChainstateActive().PreciousBlock(config, state, pindex);
	}

	bool CChainState::UnwindBlock(const Config &config, BlockValidationState &state,
	CBlockIndex *pindex, bool invalidate) {
	CBlockIndex *to_mark_failed_or_parked = pindex;
	bool pindex_was_in_chain = false;
	int disconnected = 0;
	const CChainParams &chainparams = config.GetChainParams();

	// We do not allow ActivateBestChain() to run while UnwindBlock() is
	// running, as that could cause the tip to change while we disconnect
	// blocks. (Note for backport of Core PR16849: we acquire
	// LOCK(m_cs_chainstate) in the Park, Invalidate and FinalizeBlock functions
	// due to differences in our code)
	AssertLockHeld(m_cs_chainstate);

	// We'll be acquiring and releasing cs_main below, to allow the validation
	// callbacks to run. However, we should keep the block index in a
	// consistent state as we disconnect blocks -- in particular we need to
	// add equal-work blocks to setBlockIndexCandidates as we disconnect.
	// To avoid walking the block index repeatedly in search of candidates,
	// build a map once so that we can look up candidate blocks by chain
	// work as we go.
	std::multimap<const arith_uint256, CBlockIndex *> candidate_blocks_by_work;

	{
	LOCK(cs_main);
	for (const auto &entry : m_blockman.m_block_index) {
	CBlockIndex *candidate = entry.second;
	// We don't need to put anything in our active chain into the
	// multimap, because those candidates will be found and considered
	// as we disconnect.
	// Instead, consider only non-active-chain blocks that have at
	// least as much work as where we expect the new tip to end up.
	if (!m_chain.Contains(candidate) &&
	!CBlockIndexWorkComparator()(candidate, pindex->pprev) &&
	candidate->IsValid(BlockValidity::TRANSACTIONS) &&
	candidate->HaveTxsDownloaded()) {
	candidate_blocks_by_work.insert(
	std::make_pair(candidate->nChainWork, candidate));
	}
	}
	}

	// Disconnect (descendants of) pindex, and mark them invalid.
	while (true) {
	if (ShutdownRequested()) {
	break;
	}

	// Make sure the queue of validation callbacks doesn't grow unboundedly.
	LimitValidationInterfaceQueue();

	LOCK(cs_main);
	// Lock for as long as disconnectpool is in scope to make sure
	// UpdateMempoolForReorg is called after DisconnectTip without unlocking
	// in between
	LOCK(m_mempool.cs);

	if (!m_chain.Contains(pindex)) {
	break;
	}

	pindex_was_in_chain = true;
	CBlockIndex *invalid_walk_tip = m_chain.Tip();

	// ActivateBestChain considers blocks already in m_chain
	// unconditionally valid already, so force disconnect away from it.

	DisconnectedBlockTransactions disconnectpool;

	bool ret = DisconnectTip(chainparams, state, &disconnectpool);

	// DisconnectTip will add transactions to disconnectpool.
	// Adjust the mempool to be consistent with the new tip, adding
	// transactions back to the mempool if disconnecting was successful,
	// and we're not doing a very deep invalidation (in which case
	// keeping the mempool up to date is probably futile anyway).
	disconnectpool.updateMempoolForReorg(
	config, /* fAddToMempool = */ (++disconnected <= 10) && ret,
	m_mempool);

	if (!ret) {
	return false;
	}

	assert(invalid_walk_tip->pprev == m_chain.Tip());

	// We immediately mark the disconnected blocks as invalid.
	// This prevents a case where pruned nodes may fail to invalidateblock
	// and be left unable to start as they have no tip candidates (as there
	// are no blocks that meet the "have data and are not invalid per
	// nStatus" criteria for inclusion in setBlockIndexCandidates).

	invalid_walk_tip->nStatus =
	invalidate ? invalid_walk_tip->nStatus.withFailed()
	: invalid_walk_tip->nStatus.withParked();

	setDirtyBlockIndex.insert(invalid_walk_tip);
	setBlockIndexCandidates.insert(invalid_walk_tip->pprev);

	if (invalid_walk_tip == to_mark_failed_or_parked->pprev &&
	(invalidate ? to_mark_failed_or_parked->nStatus.hasFailed()
	: to_mark_failed_or_parked->nStatus.isParked())) {
	// We only want to mark the last disconnected block as
	// Failed (or Parked); its children need to be FailedParent (or
	// ParkedParent) instead.
	to_mark_failed_or_parked->nStatus =
	(invalidate
	? to_mark_failed_or_parked->nStatus.withFailed(false)
	.withFailedParent()
	: to_mark_failed_or_parked->nStatus.withParked(false)
	.withParkedParent());

	setDirtyBlockIndex.insert(to_mark_failed_or_parked);
	}

	// Add any equal or more work headers to setBlockIndexCandidates
	auto candidate_it = candidate_blocks_by_work.lower_bound(
	invalid_walk_tip->pprev->nChainWork);
	while (candidate_it != candidate_blocks_by_work.end()) {
	if (!CBlockIndexWorkComparator()(candidate_it->second,
	invalid_walk_tip->pprev)) {
	setBlockIndexCandidates.insert(candidate_it->second);
	candidate_it = candidate_blocks_by_work.erase(candidate_it);
	} else {
	++candidate_it;
	}
	}

	// Track the last disconnected block, so we can correct its
	// FailedParent (or ParkedParent) status in future iterations, or, if
	// it's the last one, call InvalidChainFound on it.
	to_mark_failed_or_parked = invalid_walk_tip;
	}

	CheckBlockIndex(chainparams.GetConsensus());

	{
	LOCK(cs_main);
	if (m_chain.Contains(to_mark_failed_or_parked)) {
	// If the to-be-marked invalid block is in the active chain,
	// something is interfering and we can't proceed.
	return false;
	}

	// Mark pindex (or the last disconnected block) as invalid (or parked),
	// even when it never was in the main chain.
	to_mark_failed_or_parked->nStatus =
	invalidate ? to_mark_failed_or_parked->nStatus.withFailed()
	: to_mark_failed_or_parked->nStatus.withParked();
	setDirtyBlockIndex.insert(to_mark_failed_or_parked);
	if (invalidate) {
	m_blockman.m_failed_blocks.insert(to_mark_failed_or_parked);
	}

	// If any new blocks somehow arrived while we were disconnecting
	// (above), then the pre-calculation of what should go into
	// setBlockIndexCandidates may have missed entries. This would
	// technically be an inconsistency in the block index, but if we clean
	// it up here, this should be an essentially unobservable error.
	// Loop back over all block index entries and add any missing entries
	// to setBlockIndexCandidates.
	for (const std::pair<const BlockHash, CBlockIndex *> &it :
	m_blockman.m_block_index) {
	CBlockIndex *i = it.second;
	if (i->IsValid(BlockValidity::TRANSACTIONS) &&
	i->HaveTxsDownloaded() &&
	!setBlockIndexCandidates.value_comp()(i, m_chain.Tip())) {
	setBlockIndexCandidates.insert(i);
	}
	}

	if (invalidate) {
	InvalidChainFound(to_mark_failed_or_parked);
	}
	}

	// Only notify about a new block tip if the active chain was modified.
	if (pindex_was_in_chain) {
	uiInterface.NotifyBlockTip(
	GetSynchronizationState(IsInitialBlockDownload()),
	to_mark_failed_or_parked->pprev);
	}
	return true;
	}

	bool CChainState::InvalidateBlock(const Config &config,
	BlockValidationState &state,
	CBlockIndex *pindex) {
	AssertLockNotHeld(m_cs_chainstate);
	// See 'Note for backport of Core PR16849' in CChainState::UnwindBlock
	LOCK(m_cs_chainstate);

	return UnwindBlock(config, state, pindex, true);
	}

	bool CChainState::ParkBlock(const Config &config, BlockValidationState &state,
	CBlockIndex *pindex) {
	AssertLockNotHeld(m_cs_chainstate);
	// See 'Note for backport of Core PR16849' in CChainState::UnwindBlock
	LOCK(m_cs_chainstate);

	return UnwindBlock(config, state, pindex, false);
	}

	bool CChainState::FinalizeBlock(const Config &config,
	BlockValidationState &state,
	CBlockIndex *pindex) {
	AssertLockNotHeld(m_cs_chainstate);
	// See 'Note for backport of Core PR16849' in CChainState::UnwindBlock
	LOCK(m_cs_chainstate);

	AssertLockNotHeld(cs_main);
	CBlockIndex *pindexToInvalidate = nullptr;
	{
	LOCK(cs_main);
	if (!MarkBlockAsFinal(state, pindex)) {
	// state is set by MarkBlockAsFinal.
	return false;
	}

	// We have a valid candidate, make sure it is not parked.
	if (pindex->nStatus.isOnParkedChain()) {
	UnparkBlock(pindex);
	}

	// If the finalized block is on the active chain, there is no need to
	// rewind.
	if (::ChainActive().Contains(pindex)) {
	return true;
	}

	// If the finalized block is not on the active chain, that chain is
	// invalid
	// ...
	const CBlockIndex *pindexFork = ::ChainActive().FindFork(pindex);
	pindexToInvalidate = ::ChainActive().Next(pindexFork);
	if (!pindexToInvalidate) {
	return false;
	}
	} // end of locked cs_main scope

	// ... therefore, we invalidate the block on the active chain that comes
	// immediately after it
	return UnwindBlock(config, state, pindexToInvalidate,
	true /* invalidating */);
	}

	template <typename F>
	bool CChainState::UpdateFlagsForBlock(CBlockIndex *pindexBase,
	CBlockIndex *pindex, F f) {
	BlockStatus newStatus = f(pindex->nStatus);
	if (pindex->nStatus != newStatus &&
	(!pindexBase \|\|
	pindex->GetAncestor(pindexBase->nHeight) == pindexBase)) {
	pindex->nStatus = newStatus;
	setDirtyBlockIndex.insert(pindex);
	if (newStatus.isValid()) {
	m_blockman.m_failed_blocks.erase(pindex);
	}

	if (pindex->IsValid(BlockValidity::TRANSACTIONS) &&
	pindex->HaveTxsDownloaded() &&
	setBlockIndexCandidates.value_comp()(::ChainActive().Tip(),
	pindex)) {
	setBlockIndexCandidates.insert(pindex);
	}
	return true;
	}
	return false;
	}

	template <typename F, typename C, typename AC>
	void CChainState::UpdateFlags(CBlockIndex pindex, CBlockIndex &pindexReset,
	F f, C fChild, AC fAncestorWasChanged) {
	AssertLockHeld(cs_main);

	// Update the current block and ancestors; while we're doing this, identify
	// which was the deepest ancestor we changed.
	CBlockIndex *pindexDeepestChanged = pindex;
	for (auto pindexAncestor = pindex; pindexAncestor != nullptr;
	pindexAncestor = pindexAncestor->pprev) {
	if (UpdateFlagsForBlock(nullptr, pindexAncestor, f)) {
	pindexDeepestChanged = pindexAncestor;
	}
	}

	if (pindexReset &&
	pindexReset->GetAncestor(pindexDeepestChanged->nHeight) ==
	pindexDeepestChanged) {
	// reset pindexReset if it had a modified ancestor.
	pindexReset = nullptr;
	}

	// Update all blocks under modified blocks.
	BlockMap::iterator it = m_blockman.m_block_index.begin();
	while (it != m_blockman.m_block_index.end()) {
	UpdateFlagsForBlock(pindex, it->second, fChild);
	UpdateFlagsForBlock(pindexDeepestChanged, it->second,
	fAncestorWasChanged);
	it++;
	}
	}

	void CChainState::ResetBlockFailureFlags(CBlockIndex *pindex) {
	AssertLockHeld(cs_main);

	// In case we are reconsidering something before the finalization point,
	// move the finalization point to the last common ancestor.
	if (m_finalizedBlockIndex) {
	m_finalizedBlockIndex =
	LastCommonAncestor(pindex, m_finalizedBlockIndex);
	}

	UpdateFlags(
	pindex, pindexBestInvalid,
	[](const BlockStatus status) {
	return status.withClearedFailureFlags();
	},
	[](const BlockStatus status) {
	return status.withClearedFailureFlags();
	},
	[](const BlockStatus status) {
	return status.withFailedParent(false);
	});
	}

	void ResetBlockFailureFlags(CBlockIndex *pindex) {
	return ::ChainstateActive().ResetBlockFailureFlags(pindex);
	}

	void CChainState::UnparkBlockImpl(CBlockIndex *pindex, bool fClearChildren) {
	AssertLockHeld(cs_main);

	UpdateFlags(
	pindex, pindexBestParked,
	[](const BlockStatus status) {
	return status.withClearedParkedFlags();
	},
	[fClearChildren](const BlockStatus status) {
	return fClearChildren ? status.withClearedParkedFlags()
	: status.withParkedParent(false);
	},
	[](const BlockStatus status) {
	return status.withParkedParent(false);
	});
	}

	void UnparkBlockAndChildren(CBlockIndex *pindex) {
	return ::ChainstateActive().UnparkBlockImpl(pindex, true);
	}

	void UnparkBlock(CBlockIndex *pindex) {
	return ::ChainstateActive().UnparkBlockImpl(pindex, false);
	}

	bool CChainState::IsBlockFinalized(const CBlockIndex *pindex) const {
	AssertLockHeld(cs_main);
	return m_finalizedBlockIndex &&
	m_finalizedBlockIndex->GetAncestor(pindex->nHeight) == pindex;
	}

	/** Return the currently finalized block index. */
	const CBlockIndex *CChainState::GetFinalizedBlock() const {
	AssertLockHeld(cs_main);
	return m_finalizedBlockIndex;
	}

	CBlockIndex *BlockManager::AddToBlockIndex(const CBlockHeader &block) {
	AssertLockHeld(cs_main);

	// Check for duplicate
	BlockHash hash = block.GetHash();
	BlockMap::iterator it = m_block_index.find(hash);
	if (it != m_block_index.end()) {
	return it->second;
	}

	// Construct new block index object
	CBlockIndex *pindexNew = new CBlockIndex(block);
	// 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 =
	m_block_index.insert(std::make_pair(hash, pindexNew)).first;
	pindexNew->phashBlock = &((*mi).first);
	BlockMap::iterator miPrev = m_block_index.find(block.hashPrevBlock);
	if (miPrev != m_block_index.end()) {
	pindexNew->pprev = (*miPrev).second;
	pindexNew->nHeight = pindexNew->pprev->nHeight + 1;
	pindexNew->BuildSkip();
	}
	pindexNew->nTimeReceived = GetTime();
	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(BlockValidity::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).
	*/
	void CChainState::ReceivedBlockTransactions(const CBlock &block,
	CBlockIndex *pindexNew,
	const FlatFilePos &pos) {
	pindexNew->nTx = block.vtx.size();
	pindexNew->nSize = ::GetSerializeSize(block, PROTOCOL_VERSION);
	pindexNew->nFile = pos.nFile;
	pindexNew->nDataPos = pos.nPos;
	pindexNew->nUndoPos = 0;
	pindexNew->nStatus = pindexNew->nStatus.withData();
	pindexNew->RaiseValidity(BlockValidity::TRANSACTIONS);
	setDirtyBlockIndex.insert(pindexNew);

	if (pindexNew->UpdateChainStats()) {
	// 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->UpdateChainStats();
	if (pindex->nSequenceId == 0) {
	// We assign a sequence is when transaction are received to
	// prevent a miner from being able to broadcast a block but not
	// its content. However, a sequence id may have been set
	// manually, for instance via PreciousBlock, in which case, we
	// don't need to assign one.
	pindex->nSequenceId = nBlockSequenceId++;
	}

	if (m_chain.Tip() == nullptr \|\|
	!setBlockIndexCandidates.value_comp()(pindex, m_chain.Tip())) {
	setBlockIndexCandidates.insert(pindex);
	}

	std::pair<std::multimap<CBlockIndex , CBlockIndex >::iterator,
	std::multimap<CBlockIndex , CBlockIndex >::iterator>
	range = m_blockman.m_blocks_unlinked.equal_range(pindex);
	while (range.first != range.second) {
	std::multimap<CBlockIndex , CBlockIndex >::iterator it =
	range.first;
	queue.push_back(it->second);
	range.first++;
	m_blockman.m_blocks_unlinked.erase(it);
	}
	}
	} else if (pindexNew->pprev &&
	pindexNew->pprev->IsValid(BlockValidity::TREE)) {
	m_blockman.m_blocks_unlinked.insert(
	std::make_pair(pindexNew->pprev, pindexNew));
	}
	}

	static bool FindBlockPos(FlatFilePos &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);
	}

	bool finalize_undo = false;
	if (!fKnown) {
	while (vinfoBlockFile[nFile].nSize + nAddSize >= MAX_BLOCKFILE_SIZE) {
	// when the undo file is keeping up with the block file, we want to
	// flush it explicitly when it is lagging behind (more blocks arrive
	// than are being connected), we let the undo block write case
	// handle it
	finalize_undo = (vinfoBlockFile[nFile].nHeightLast ==
	(unsigned int)ChainActive().Tip()->nHeight);
	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, finalize_undo);
	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) {
	bool out_of_space;
	size_t bytes_allocated =
	BlockFileSeq().Allocate(pos, nAddSize, out_of_space);
	if (out_of_space) {
	return AbortNode("Disk space is too low!",
	_("Disk space is too low!"));
	}
	if (bytes_allocated != 0 && fPruneMode) {
	fCheckForPruning = true;
	}
	}

	setDirtyFileInfo.insert(nFile);
	return true;
	}

	static bool FindUndoPos(BlockValidationState &state, int nFile,
	FlatFilePos &pos, unsigned int nAddSize) {
	pos.nFile = nFile;

	LOCK(cs_LastBlockFile);

	pos.nPos = vinfoBlockFile[nFile].nUndoSize;
	vinfoBlockFile[nFile].nUndoSize += nAddSize;
	setDirtyFileInfo.insert(nFile);

	bool out_of_space;
	size_t bytes_allocated =
	UndoFileSeq().Allocate(pos, nAddSize, out_of_space);
	if (out_of_space) {
	return AbortNode(state, "Disk space is too low!",
	_("Disk space is too low!"));
	}
	if (bytes_allocated != 0 && fPruneMode) {
	fCheckForPruning = true;
	}

	return true;
	}

	/**
	* Return true if the provided block header is valid.
	* Only verify PoW if blockValidationOptions is configured to do so.
	* This allows validation of headers on which the PoW hasn't been done.
	* For example: to validate template handed to mining software.
	* Do not call this for any check that depends on the context.
	* For context-dependent calls, see ContextualCheckBlockHeader.
	*/
	static bool CheckBlockHeader(const CBlockHeader &block,
	BlockValidationState &state,
	const Consensus::Params &params,
	BlockValidationOptions validationOptions) {
	// Check proof of work matches claimed amount
	if (validationOptions.shouldValidatePoW() &&
	!CheckProofOfWork(block.GetHash(), block.nBits, params)) {
	return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER,
	"high-hash", "proof of work failed");
	}

	return true;
	}

	bool CheckBlock(const CBlock &block, BlockValidationState &state,
	const Consensus::Params &params,
	BlockValidationOptions validationOptions) {
	// 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, params, validationOptions)) {
	return false;
	}

	// Check the merkle root.
	if (validationOptions.shouldValidateMerkleRoot()) {
	bool mutated;
	uint256 hashMerkleRoot2 = BlockMerkleRoot(block, &mutated);
	if (block.hashMerkleRoot != hashMerkleRoot2) {
	return state.Invalid(BlockValidationResult::BLOCK_MUTATED,
	"bad-txnmrklroot", "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.Invalid(BlockValidationResult::BLOCK_MUTATED,
	"bad-txns-duplicate", "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.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	"bad-cb-missing", "first tx is not coinbase");
	}

	// Size limits.
	auto nMaxBlockSize = validationOptions.getExcessiveBlockSize();

	// Bail early if there is no way this block is of reasonable size.
	if ((block.vtx.size() * MIN_TRANSACTION_SIZE) > nMaxBlockSize) {
	return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	"bad-blk-length", "size limits failed");
	}

	auto currentBlockSize = ::GetSerializeSize(block, PROTOCOL_VERSION);
	if (currentBlockSize > nMaxBlockSize) {
	return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	"bad-blk-length", "size limits failed");
	}

	// And a valid coinbase.
	TxValidationState tx_state;
	if (!CheckCoinbase(*block.vtx[0], tx_state)) {
	return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	tx_state.GetRejectReason(),
	strprintf("Coinbase check failed (txid %s) %s",
	block.vtx[0]->GetId().ToString(),
	tx_state.GetDebugMessage()));
	}

	// Check transactions for regularity, skipping the first. Note that this
	// is the first time we check that all after the first are !IsCoinBase.
	for (size_t i = 1; i < block.vtx.size(); i++) {
	auto *tx = block.vtx[i].get();
	if (!CheckRegularTransaction(*tx, tx_state)) {
	return state.Invalid(
	BlockValidationResult::BLOCK_CONSENSUS,
	tx_state.GetRejectReason(),
	strprintf("Transaction check failed (txid %s) %s",
	tx->GetId().ToString(), tx_state.GetDebugMessage()));
	}
	}

	if (validationOptions.shouldValidatePoW() &&
	validationOptions.shouldValidateMerkleRoot()) {
	block.fChecked = true;
	}

	return true;
	}

	/**
	* Context-dependent validity checks.
	* By "context", we mean only the previous block headers, but not the UTXO
	* set; UTXO-related validity checks are done in ConnectBlock().
	* NOTE: This function is not currently invoked by ConnectBlock(), so we
	* should consider upgrade issues if we change which consensus rules are
	* enforced in this function (eg by adding a new consensus rule). See comment
	* in ConnectBlock().
	* Note that -reindex-chainstate skips the validation that happens here!
	*/
	static bool ContextualCheckBlockHeader(const CChainParams &params,
	const CBlockHeader &block,
	BlockValidationState &state,
	const CBlockIndex *pindexPrev,
	int64_t nAdjustedTime)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
	assert(pindexPrev != nullptr);
	const int nHeight = pindexPrev->nHeight + 1;

	// Check proof of work
	if (block.nBits != GetNextWorkRequired(pindexPrev, &block, params)) {
	LogPrintf("bad bits after height: %d\n", pindexPrev->nHeight);
	return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER,
	"bad-diffbits", "incorrect proof of work");
	}

	// Check against checkpoints
	if (fCheckpointsEnabled) {
	const CCheckpointData &checkpoints = params.Checkpoints();

	// Check that the block chain matches the known block chain up to a
	// checkpoint.
	if (!Checkpoints::CheckBlock(checkpoints, nHeight, block.GetHash())) {
	LogPrintf("ERROR: %s: rejected by checkpoint lock-in at %d\n",
	__func__, nHeight);
	return state.Invalid(BlockValidationResult::BLOCK_CHECKPOINT,
	"checkpoint mismatch");
	}

	// Don't accept any forks from the main chain prior to last checkpoint.
	// GetLastCheckpoint finds the last checkpoint in MapCheckpoints that's
	// in our BlockIndex().
	CBlockIndex *pcheckpoint = Checkpoints::GetLastCheckpoint(checkpoints);
	if (pcheckpoint && nHeight < pcheckpoint->nHeight) {
	LogPrintf("ERROR: %s: forked chain older than last checkpoint "
	"(height %d)\n",
	__func__, nHeight);
	return state.Invalid(BlockValidationResult::BLOCK_CHECKPOINT,
	"bad-fork-prior-to-checkpoint");
	}
	}

	// Check timestamp against prev
	if (block.GetBlockTime() <= pindexPrev->GetMedianTimePast()) {
	return state.Invalid(BlockValidationResult::BLOCK_INVALID_HEADER,
	"time-too-old", "block's timestamp is too early");
	}

	// Check timestamp
	if (block.GetBlockTime() > nAdjustedTime + MAX_FUTURE_BLOCK_TIME) {
	return state.Invalid(BlockValidationResult::BLOCK_TIME_FUTURE,
	"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
	const Consensus::Params &consensusParams = params.GetConsensus();
	if ((block.nVersion < 2 && nHeight >= consensusParams.BIP34Height) \|\|
	(block.nVersion < 3 && nHeight >= consensusParams.BIP66Height) \|\|
	(block.nVersion < 4 && nHeight >= consensusParams.BIP65Height)) {
	return state.Invalid(
	BlockValidationResult::BLOCK_INVALID_HEADER,
	strprintf("bad-version(0x%08x)", block.nVersion),
	strprintf("rejected nVersion=0x%08x block", block.nVersion));
	}

	return true;
	}

	bool ContextualCheckTransactionForCurrentBlock(const Consensus::Params &params,
	const CTransaction &tx,
	TxValidationState &state,
	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() == nullptr
	? 0
	: ::ChainActive().Tip()->GetMedianTimePast();
	const int64_t nLockTimeCutoff = (flags & LOCKTIME_MEDIAN_TIME_PAST)
	? nMedianTimePast
	: GetAdjustedTime();

	return ContextualCheckTransaction(params, tx, state, nBlockHeight,
	nLockTimeCutoff, nMedianTimePast);
	}

	/**
	* NOTE: This function is not currently invoked by ConnectBlock(), so we
	* should consider upgrade issues if we change which consensus rules are
	* enforced in this function (eg by adding a new consensus rule). See comment
	* in ConnectBlock().
	* Note that -reindex-chainstate skips the validation that happens here!
	*/
	static bool ContextualCheckBlock(const CBlock &block,
	BlockValidationState &state,
	const Consensus::Params &params,
	const CBlockIndex *pindexPrev) {
	const int nHeight = pindexPrev == nullptr ? 0 : pindexPrev->nHeight + 1;

	// Start enforcing BIP113 (Median Time Past).
	int nLockTimeFlags = 0;
	if (nHeight >= params.CSVHeight) {
	assert(pindexPrev != nullptr);
	nLockTimeFlags \|= LOCKTIME_MEDIAN_TIME_PAST;
	}

	const int64_t nMedianTimePast =
	pindexPrev == nullptr ? 0 : pindexPrev->GetMedianTimePast();

	const int64_t nLockTimeCutoff = (nLockTimeFlags & LOCKTIME_MEDIAN_TIME_PAST)
	? nMedianTimePast
	: block.GetBlockTime();

	const bool fIsMagneticAnomalyEnabled =
	IsMagneticAnomalyEnabled(params, pindexPrev);

	// Check transactions:
	// - canonical ordering
	// - ensure they are finalized
	// - perform a preliminary block-sigops count (they will be recounted more
	// strictly during ConnectBlock).
	// - perform a transaction-sigops check (again, a more strict check will
	// happen in ConnectBlock).
	const CTransaction *prevTx = nullptr;
	for (const auto &ptx : block.vtx) {
	const CTransaction &tx = *ptx;
	if (fIsMagneticAnomalyEnabled) {
	if (prevTx && (tx.GetId() <= prevTx->GetId())) {
	if (tx.GetId() == prevTx->GetId()) {
	return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	"tx-duplicate",
	strprintf("Duplicated transaction %s",
	tx.GetId().ToString()));
	}

	return state.Invalid(
	BlockValidationResult::BLOCK_CONSENSUS, "tx-ordering",
	strprintf("Transaction order is invalid (%s < %s)",
	tx.GetId().ToString(),
	prevTx->GetId().ToString()));
	}

	if (prevTx \|\| !tx.IsCoinBase()) {
	prevTx = &tx;
	}
	}

	TxValidationState tx_state;
	if (!ContextualCheckTransaction(params, tx, tx_state, nHeight,
	nLockTimeCutoff, nMedianTimePast)) {
	return state.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	tx_state.GetRejectReason(),
	tx_state.GetDebugMessage());
	}
	}

	// Enforce rule that the coinbase starts with serialized block height
	if (nHeight >= params.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.Invalid(BlockValidationResult::BLOCK_CONSENSUS,
	"bad-cb-height",
	"block height mismatch in coinbase");
	}
	}

	return true;
	}

	/**
	* If the provided block header is valid, add it to the block index.
	*
	* Returns true if the block is successfully added to the block index.
	*/
	bool BlockManager::AcceptBlockHeader(const Config &config,
	const CBlockHeader &block,
	BlockValidationState &state,
	CBlockIndex **ppindex) {
	AssertLockHeld(cs_main);
	const CChainParams &chainparams = config.GetChainParams();

	// Check for duplicate
	BlockHash hash = block.GetHash();
	BlockMap::iterator miSelf = m_block_index.find(hash);
	CBlockIndex *pindex = nullptr;
	if (hash != chainparams.GetConsensus().hashGenesisBlock) {
	if (miSelf != m_block_index.end()) {
	// Block header is already known.
	pindex = miSelf->second;
	if (ppindex) {
	*ppindex = pindex;
	}

	if (pindex->nStatus.isInvalid()) {
	LogPrintf("ERROR: %s: block %s is marked invalid\n", __func__,
	hash.ToString());
	return state.Invalid(
	BlockValidationResult::BLOCK_CACHED_INVALID, "duplicate");
	}

	return true;
	}

	if (!CheckBlockHeader(block, state, chainparams.GetConsensus(),
	BlockValidationOptions(config))) {
	LogPrint(BCLog::VALIDATION,
	"%s: Consensus::CheckBlockHeader: %s, %s\n", __func__,
	hash.ToString(), state.ToString());
	return false;
	}

	// Get prev block index
	BlockMap::iterator mi = m_block_index.find(block.hashPrevBlock);
	if (mi == m_block_index.end()) {
	LogPrintf("ERROR: %s: prev block not found\n", __func__);
	return state.Invalid(BlockValidationResult::BLOCK_MISSING_PREV,
	"prev-blk-not-found");
	}

	CBlockIndex pindexPrev = (mi).second;
	assert(pindexPrev);
	if (pindexPrev->nStatus.isInvalid()) {
	LogPrintf("ERROR: %s: prev block invalid\n", __func__);
	return state.Invalid(BlockValidationResult::BLOCK_INVALID_PREV,
	"bad-prevblk");
	}

	if (!ContextualCheckBlockHeader(chainparams, block, state, pindexPrev,
	GetAdjustedTime())) {
	return error("%s: Consensus::ContextualCheckBlockHeader: %s, %s",
	__func__, hash.ToString(), state.ToString());
	}

	/* Determine if this block descends from any block which has been found
	* invalid (m_failed_blocks), then mark pindexPrev and any blocks
	* between them as failed. For example:
	*
	* D3
	* /
	* B2 - C2
	* / \
	* A D2 - E2 - F2
	* \
	* B1 - C1 - D1 - E1
	*
	* In the case that we attempted to reorg from E1 to F2, only to find
	* C2 to be invalid, we would mark D2, E2, and F2 as BLOCK_FAILED_CHILD
	* but NOT D3 (it was not in any of our candidate sets at the time).
	*
	* In any case D3 will also be marked as BLOCK_FAILED_CHILD at restart
	* in LoadBlockIndex.
	*/
	if (!pindexPrev->IsValid(BlockValidity::SCRIPTS)) {
	// The above does not mean "invalid": it checks if the previous
	// block hasn't been validated up to BlockValidity::SCRIPTS. This is
	// a performance optimization, in the common case of adding a new
	// block to the tip, we don't need to iterate over the failed blocks
	// list.
	for (const CBlockIndex *failedit : m_failed_blocks) {
	if (pindexPrev->GetAncestor(failedit->nHeight) == failedit) {
	assert(failedit->nStatus.hasFailed());
	CBlockIndex *invalid_walk = pindexPrev;
	while (invalid_walk != failedit) {
	invalid_walk->nStatus =
	invalid_walk->nStatus.withFailedParent();
	setDirtyBlockIndex.insert(invalid_walk);
	invalid_walk = invalid_walk->pprev;
	}
	LogPrintf("ERROR: %s: prev block invalid\n", __func__);
	return state.Invalid(
	BlockValidationResult::BLOCK_INVALID_PREV,
	"bad-prevblk");
	}
	}
	}
	}

	if (pindex == nullptr) {
	pindex = AddToBlockIndex(block);
	}

	if (ppindex) {
	*ppindex = pindex;
	}

	return true;
	}

	// Exposed wrapper for AcceptBlockHeader
	bool ChainstateManager::ProcessNewBlockHeaders(
	const Config &config, const std::vector<CBlockHeader> &headers,
	BlockValidationState &state, const CBlockIndex **ppindex) {
	AssertLockNotHeld(cs_main);
	{
	LOCK(cs_main);
	for (const CBlockHeader &header : headers) {
	// Use a temp pindex instead of ppindex to avoid a const_cast
	CBlockIndex *pindex = nullptr;
	bool accepted =
	m_blockman.AcceptBlockHeader(config, header, state, &pindex);
	::ChainstateActive().CheckBlockIndex(
	config.GetChainParams().GetConsensus());

	if (!accepted) {
	return false;
	}

	if (ppindex) {
	*ppindex = pindex;
	}
	}
	}

	if (NotifyHeaderTip()) {
	if (::ChainstateActive().IsInitialBlockDownload() && ppindex &&
	*ppindex) {
	LogPrintf("Synchronizing blockheaders, height: %d (~%.2f%%)\n",
	(*ppindex)->nHeight,
	100.0 /
	((*ppindex)->nHeight +
	(GetAdjustedTime() - (*ppindex)->GetBlockTime()) /
	Params().GetConsensus().nPowTargetSpacing) *
	(*ppindex)->nHeight);
	}
	}
	return true;
	}

	/**
	* Store block on disk. If dbp is non-nullptr, the file is known to already
	* reside on disk.
	*/
	static FlatFilePos SaveBlockToDisk(const CBlock &block, int nHeight,
	const CChainParams &chainparams,
	const FlatFilePos *dbp) {
	unsigned int nBlockSize = ::GetSerializeSize(block, CLIENT_VERSION);
	FlatFilePos blockPos;
	if (dbp != nullptr) {
	blockPos = *dbp;
	}
	if (!FindBlockPos(blockPos, nBlockSize + 8, nHeight, block.GetBlockTime(),
	dbp != nullptr)) {
	error("%s: FindBlockPos failed", __func__);
	return FlatFilePos();
	}
	if (dbp == nullptr) {
	if (!WriteBlockToDisk(block, blockPos, chainparams.DiskMagic())) {
	AbortNode("Failed to write block");
	return FlatFilePos();
	}
	}
	return blockPos;
	}

	/**
	* Store a block on disk.
	*
	* @param[in] config The global config.
	* @param[in-out] pblock The block we want to accept.
	* @param[in] fRequested A boolean to indicate if this block was requested
	* from our peers.
	* @param[in] dbp If non-null, the disk position of the block.
	* @param[in-out] fNewBlock True if block was first received via this call.
	* @return True if the block is accepted as a valid block and written to disk.
	*/
	bool CChainState::AcceptBlock(const Config &config,
	const std::shared_ptr<const CBlock> &pblock,
	BlockValidationState &state, bool fRequested,
	const FlatFilePos dbp, bool fNewBlock) {
	AssertLockHeld(cs_main);

	const CBlock &block = *pblock;
	if (fNewBlock) {
	*fNewBlock = false;
	}

	CBlockIndex *pindex = nullptr;

	bool accepted_header =
	m_blockman.AcceptBlockHeader(config, block, state, &pindex);
	CheckBlockIndex(config.GetChainParams().GetConsensus());

	if (!accepted_header) {
	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.hasData();

	// TODO: deal better with return value and error conditions for duplicate
	// and unrequested blocks.
	if (fAlreadyHave) {
	return true;
	}

	// Compare block header timestamps and received times of the block and the
	// chaintip. If they have the same chain height, use these diffs as a
	// tie-breaker, attempting to pick the more honestly-mined block.
	int64_t newBlockTimeDiff = std::llabs(pindex->GetReceivedTimeDiff());
	int64_t chainTipTimeDiff =
	m_chain.Tip() ? std::llabs(m_chain.Tip()->GetReceivedTimeDiff()) : 0;

	bool isSameHeight =
	m_chain.Tip() && (pindex->nChainWork == m_chain.Tip()->nChainWork);
	if (isSameHeight) {
	LogPrintf("Chain tip timestamp-to-received-time difference: hash=%s, "
	"diff=%d\n",
	m_chain.Tip()->GetBlockHash().ToString(), chainTipTimeDiff);
	LogPrintf("New block timestamp-to-received-time difference: hash=%s, "
	"diff=%d\n",
	pindex->GetBlockHash().ToString(), newBlockTimeDiff);
	}

	bool fHasMoreOrSameWork =
	(m_chain.Tip() ? pindex->nChainWork >= m_chain.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(m_chain.Height() + MIN_BLOCKS_TO_KEEP));

	// TODO: Decouple this function from the block download logic by removing
	// fRequested
	// This requires some new chain data structure 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.

	// 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 (!fHasMoreOrSameWork) {
	return true;
	}

	// Block height is too high.
	if (fTooFarAhead) {
	return true;
	}

	// Protect against DoS attacks from low-work chains.
	// If our tip is behind, a peer could try to send us
	// low-work blocks on a fake chain that we would never
	// request; don't process these.
	if (pindex->nChainWork < nMinimumChainWork) {
	return true;
	}
	}

	const CChainParams &chainparams = config.GetChainParams();
	const Consensus::Params &consensusParams = chainparams.GetConsensus();

	if (!CheckBlock(block, state, consensusParams,
	BlockValidationOptions(config)) \|\|
	!ContextualCheckBlock(block, state, consensusParams, pindex->pprev)) {
	if (state.IsInvalid() &&
	state.GetResult() != BlockValidationResult::BLOCK_MUTATED) {
	pindex->nStatus = pindex->nStatus.withFailed();
	setDirtyBlockIndex.insert(pindex);
	}

	return error("%s: %s (block %s)", __func__, state.ToString(),
	block.GetHash().ToString());
	}

	// If connecting the new block would require rewinding more than one block
	// from the active chain (i.e., a "deep reorg"), then mark the new block as
	// parked. If it has enough work then it will be automatically unparked
	// later, during FindMostWorkChain. We mark the block as parked at the very
	// last minute so we can make sure everything is ready to be reorged if
	// needed.
	if (gArgs.GetBoolArg("-parkdeepreorg", true)) {
	const CBlockIndex *pindexFork = m_chain.FindFork(pindex);
	if (pindexFork && pindexFork->nHeight + 1 < m_chain.Height()) {
	LogPrintf("Park block %s as it would cause a deep reorg.\n",
	pindex->GetBlockHash().ToString());
	pindex->nStatus = pindex->nStatus.withParked();
	setDirtyBlockIndex.insert(pindex);
	}
	}

	// Header is valid/has work and the merkle tree is good.
	// Relay now, but if it does not build on our best tip, let the
	// SendMessages loop relay it.
	if (!IsInitialBlockDownload() && m_chain.Tip() == pindex->pprev) {
	GetMainSignals().NewPoWValidBlock(pindex, pblock);
	}

	// Write block to history file
	if (fNewBlock) {
	*fNewBlock = true;
	}
	try {
	FlatFilePos blockPos =
	SaveBlockToDisk(block, pindex->nHeight, chainparams, dbp);
	if (blockPos.IsNull()) {
	state.Error(strprintf(
	"%s: Failed to find position to write new block to disk",
	__func__));
	return false;
	}
	ReceivedBlockTransactions(block, pindex, blockPos);
	} catch (const std::runtime_error &e) {
	return AbortNode(state, std::string("System error: ") + e.what());
	}

	FlushStateToDisk(chainparams, state, FlushStateMode::NONE);

	CheckBlockIndex(consensusParams);

	return true;
	}

	bool ChainstateManager::ProcessNewBlock(
	const Config &config, const std::shared_ptr<const CBlock> pblock,
	bool fForceProcessing, bool *fNewBlock) {
	AssertLockNotHeld(cs_main);

	{
	if (fNewBlock) {
	*fNewBlock = false;
	}

	BlockValidationState state;

	// CheckBlock() does not support multi-threaded block validation
	// because CBlock::fChecked can cause data race.
	// Therefore, the following critical section must include the
	// CheckBlock() call as well.
	LOCK(cs_main);

	// Ensure that CheckBlock() passes before calling AcceptBlock, as
	// belt-and-suspenders.
	bool ret =
	CheckBlock(*pblock, state, config.GetChainParams().GetConsensus(),
	BlockValidationOptions(config));
	if (ret) {
	// Store to disk
	ret = ::ChainstateActive().AcceptBlock(
	config, pblock, state, fForceProcessing, nullptr, fNewBlock);
	}

	if (!ret) {
	GetMainSignals().BlockChecked(*pblock, state);
	return error("%s: AcceptBlock FAILED (%s)", __func__,
	state.ToString());
	}
	}

	NotifyHeaderTip();

	// Only used to report errors, not invalidity - ignore it
	BlockValidationState state;
	if (!::ChainstateActive().ActivateBestChain(config, state, pblock)) {
	return error("%s: ActivateBestChain failed (%s)", __func__,
	state.ToString());
	}

	return true;
	}

	bool TestBlockValidity(BlockValidationState &state, const CChainParams &params,
	const CBlock &block, CBlockIndex *pindexPrev,
	BlockValidationOptions validationOptions) {
	AssertLockHeld(cs_main);
	assert(pindexPrev && pindexPrev == ::ChainActive().Tip());
	CCoinsViewCache viewNew(&::ChainstateActive().CoinsTip());
	BlockHash block_hash(block.GetHash());
	CBlockIndex indexDummy(block);
	indexDummy.pprev = pindexPrev;
	indexDummy.nHeight = pindexPrev->nHeight + 1;
	indexDummy.phashBlock = &block_hash;

	// NOTE: CheckBlockHeader is called by CheckBlock
	if (!ContextualCheckBlockHeader(params, block, state, pindexPrev,
	GetAdjustedTime())) {
	return error("%s: Consensus::ContextualCheckBlockHeader: %s", __func__,
	state.ToString());
	}

	if (!CheckBlock(block, state, params.GetConsensus(), validationOptions)) {
	return error("%s: Consensus::CheckBlock: %s", __func__,
	state.ToString());
	}

	if (!ContextualCheckBlock(block, state, params.GetConsensus(),
	pindexPrev)) {
	return error("%s: Consensus::ContextualCheckBlock: %s", __func__,
	state.ToString());
	}

	if (!::ChainstateActive().ConnectBlock(block, state, &indexDummy, viewNew,
	params, validationOptions, 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() {
	LOCK(cs_LastBlockFile);

	uint64_t retval = 0;
	for (const CBlockFileInfo &file : vinfoBlockFile) {
	retval += file.nSize + file.nUndoSize;
	}

	return retval;
	}

	void BlockManager::PruneOneBlockFile(const int fileNumber) {
	AssertLockHeld(cs_main);
	LOCK(cs_LastBlockFile);

	for (const auto &entry : m_block_index) {
	CBlockIndex *pindex = entry.second;
	if (pindex->nFile == fileNumber) {
	pindex->nStatus = pindex->nStatus.withData(false).withUndo(false);
	pindex->nFile = 0;
	pindex->nDataPos = 0;
	pindex->nUndoPos = 0;
	setDirtyBlockIndex.insert(pindex);

	// Prune from m_blocks_unlinked -- 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
	// m_blocks_unlinked or setBlockIndexCandidates.
	auto range = m_blocks_unlinked.equal_range(pindex->pprev);
	while (range.first != range.second) {
	std::multimap<CBlockIndex , CBlockIndex >::iterator _it =
	range.first;
	range.first++;
	if (_it->second == pindex) {
	m_blocks_unlinked.erase(_it);
	}
	}
	}
	}

	vinfoBlockFile[fileNumber].SetNull();
	setDirtyFileInfo.insert(fileNumber);
	}

	void UnlinkPrunedFiles(const std::set<int> &setFilesToPrune) {
	for (const int i : setFilesToPrune) {
	FlatFilePos pos(i, 0);
	fs::remove(BlockFileSeq().FileName(pos));
	fs::remove(UndoFileSeq().FileName(pos));
	LogPrintf("Prune: %s deleted blk/rev (%05u)\n", __func__, i);
	}
	}

	void BlockManager::FindFilesToPruneManual(std::set<int> &setFilesToPrune,
	int nManualPruneHeight,
	int chain_tip_height) {
	assert(fPruneMode && nManualPruneHeight > 0);

	LOCK2(cs_main, cs_LastBlockFile);
	if (chain_tip_height < 0) {
	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, chain_tip_height - 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) {
	BlockValidationState state;
	const CChainParams &chainparams = Params();
	if (!::ChainstateActive().FlushStateToDisk(
	chainparams, state, FlushStateMode::NONE, nManualPruneHeight)) {
	LogPrintf("%s: failed to flush state (%s)\n", __func__,
	state.ToString());
	}
	}

	void BlockManager::FindFilesToPrune(std::set<int> &setFilesToPrune,
	uint64_t nPruneAfterHeight,
	int chain_tip_height, bool is_ibd) {
	LOCK2(cs_main, cs_LastBlockFile);
	if (chain_tip_height < 0 \|\| nPruneTarget == 0) {
	return;
	}
	if (uint64_t(chain_tip_height) <= nPruneAfterHeight) {
	return;
	}

	unsigned int nLastBlockWeCanPrune = chain_tip_height - 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) {
	// On a prune event, the chainstate DB is flushed.
	// To avoid excessive prune events negating the benefit of high dbcache
	// values, we should not prune too rapidly.
	// So when pruning in IBD, increase the buffer a bit to avoid a re-prune
	// too soon.
	if (is_ibd) {
	// Since this is only relevant during IBD, we use a fixed 10%
	nBuffer += nPruneTarget / 10;
	}

	for (int fileNumber = 0; fileNumber < nLastBlockFile; fileNumber++) {
	nBytesToPrune = vinfoBlockFile[fileNumber].nSize +
	vinfoBlockFile[fileNumber].nUndoSize;

	if (vinfoBlockFile[fileNumber].nSize == 0) {
	continue;
	}

	// are we below our target?
	if (nCurrentUsage + nBuffer < nPruneTarget) {
	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(BCLog::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);
	}

	CBlockIndex *BlockManager::InsertBlockIndex(const BlockHash &hash) {
	AssertLockHeld(cs_main);

	if (hash.IsNull()) {
	return nullptr;
	}

	// Return existing
	BlockMap::iterator mi = m_block_index.find(hash);
	if (mi != m_block_index.end()) {
	return (*mi).second;
	}

	// Create new
	CBlockIndex *pindexNew = new CBlockIndex();
	mi = m_block_index.insert(std::make_pair(hash, pindexNew)).first;
	pindexNew->phashBlock = &((*mi).first);

	return pindexNew;
	}

	bool BlockManager::LoadBlockIndex(
	const Consensus::Params &params, CBlockTreeDB &blocktree,
	std::set<CBlockIndex *, CBlockIndexWorkComparator>
	&block_index_candidates) {
	AssertLockHeld(cs_main);
	if (!blocktree.LoadBlockIndexGuts(
	params, [this](const BlockHash &hash) EXCLUSIVE_LOCKS_REQUIRED(
	cs_main) { return this->InsertBlockIndex(hash); })) {
	return false;
	}

	// Calculate nChainWork
	std::vector<std::pair<int, CBlockIndex *>> vSortedByHeight;
	vSortedByHeight.reserve(m_block_index.size());
	for (const std::pair<const BlockHash, CBlockIndex *> &item :
	m_block_index) {
	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) {
	if (ShutdownRequested()) {
	return false;
	}
	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->UpdateChainStats() && pindex->pprev) {
	m_blocks_unlinked.insert(std::make_pair(pindex->pprev, pindex));
	}
	}

	if (!pindex->nStatus.hasFailed() && pindex->pprev &&
	pindex->pprev->nStatus.hasFailed()) {
	pindex->nStatus = pindex->nStatus.withFailedParent();
	setDirtyBlockIndex.insert(pindex);
	}
	if (pindex->IsValid(BlockValidity::TRANSACTIONS) &&
	(pindex->HaveTxsDownloaded() \|\| pindex->pprev == nullptr)) {
	block_index_candidates.insert(pindex);
	}

	if (pindex->nStatus.isInvalid() &&
	(!pindexBestInvalid \|\|
	pindex->nChainWork > pindexBestInvalid->nChainWork)) {
	pindexBestInvalid = pindex;
	}

	if (pindex->nStatus.isOnParkedChain() &&
	(!pindexBestParked \|\|
	pindex->nChainWork > pindexBestParked->nChainWork)) {
	pindexBestParked = pindex;
	}

	if (pindex->pprev) {
	pindex->BuildSkip();
	}

	if (pindex->IsValid(BlockValidity::TREE) &&
	(pindexBestHeader == nullptr \|\|
	CBlockIndexWorkComparator()(pindexBestHeader, pindex))) {
	pindexBestHeader = pindex;
	}
	}

	return true;
	}

	void BlockManager::Unload() {
	m_failed_blocks.clear();
	m_blocks_unlinked.clear();

	for (const BlockMap::value_type &entry : m_block_index) {
	delete entry.second;
	}

	m_block_index.clear();
	}

	static bool LoadBlockIndexDB(ChainstateManager &chainman,
	const Consensus::Params &params)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
	if (!chainman.m_blockman.LoadBlockIndex(
	params, *pblocktree,
	::ChainstateActive().setBlockIndexCandidates)) {
	return false;
	}

	// 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<const BlockHash, CBlockIndex *> &item :
	chainman.BlockIndex()) {
	CBlockIndex *pindex = item.second;
	if (pindex->nStatus.hasData()) {
	setBlkDataFiles.insert(pindex->nFile);
	}
	}

	for (const int i : setBlkDataFiles) {
	FlatFilePos pos(i, 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
	if (pblocktree->IsReindexing()) {
	fReindex = true;
	}

	return true;
	}

	void CChainState::LoadMempool(const Config &config, const ArgsManager &args) {
	if (args.GetArg("-persistmempool", DEFAULT_PERSIST_MEMPOOL)) {
	::LoadMempool(config, m_mempool);
	}
	m_mempool.SetIsLoaded(!ShutdownRequested());
	}

	bool CChainState::LoadChainTip(const CChainParams &chainparams) {
	AssertLockHeld(cs_main);
	const CCoinsViewCache &coins_cache = CoinsTip();
	// Never called when the coins view is empty
	assert(!coins_cache.GetBestBlock().IsNull());
	const CBlockIndex *tip = m_chain.Tip();

	if (tip && tip->GetBlockHash() == coins_cache.GetBestBlock()) {
	return true;
	}

	// Load pointer to end of best chain
	CBlockIndex *pindex = LookupBlockIndex(coins_cache.GetBestBlock());
	if (!pindex) {
	return false;
	}
	m_chain.SetTip(pindex);
	PruneBlockIndexCandidates();

	tip = m_chain.Tip();
	LogPrintf(
	"Loaded best chain: hashBestChain=%s height=%d date=%s progress=%f\n",
	tip->GetBlockHash().ToString(), m_chain.Height(),
	FormatISO8601DateTime(tip->GetBlockTime()),
	GuessVerificationProgress(chainparams.TxData(), tip));
	return true;
	}

	CVerifyDB::CVerifyDB() {
	uiInterface.ShowProgress(_("Verifying blocks...").translated, 0, false);
	}

	CVerifyDB::~CVerifyDB() {
	uiInterface.ShowProgress("", 100, false);
	}

	bool CVerifyDB::VerifyDB(const Config &config, CCoinsView *coinsview,
	int nCheckLevel, int nCheckDepth) {
	LOCK(cs_main);

	const CChainParams &params = config.GetChainParams();
	const Consensus::Params &consensusParams = params.GetConsensus();

	if (::ChainActive().Tip() == nullptr \|\|
	::ChainActive().Tip()->pprev == nullptr) {
	return true;
	}

	// Verify blocks in the best chain
	if (nCheckDepth <= 0 \|\| 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 *pindex;
	CBlockIndex *pindexFailure = nullptr;
	int nGoodTransactions = 0;
	BlockValidationState state;
	int reportDone = 0;
	LogPrintfToBeContinued("[0%%]...");
	for (pindex = ::ChainActive().Tip(); pindex && pindex->pprev;
	pindex = pindex->pprev) {
	const 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
	LogPrintfToBeContinued("[%d%%]...", percentageDone);
	reportDone = percentageDone / 10;
	}

	uiInterface.ShowProgress(_("Verifying blocks...").translated,
	percentageDone, false);
	if (pindex->nHeight <= ::ChainActive().Height() - nCheckDepth) {
	break;
	}

	if (fPruneMode && !pindex->nStatus.hasData()) {
	// 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, consensusParams)) {
	return error(
	"VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s",
	pindex->nHeight, pindex->GetBlockHash().ToString());
	}

	// check level 1: verify block validity
	if (nCheckLevel >= 1 && !CheckBlock(block, state, consensusParams,
	BlockValidationOptions(config))) {
	return error("%s: *** found bad block at %d, hash=%s (%s)\n",
	__func__, pindex->nHeight,
	pindex->GetBlockHash().ToString(), state.ToString());
	}

	// check level 2: verify undo validity
	if (nCheckLevel >= 2 && pindex) {
	CBlockUndo undo;
	if (!pindex->GetUndoPos().IsNull()) {
	if (!UndoReadFromDisk(undo, pindex)) {
	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 &&
	(coins.DynamicMemoryUsage() +
	::ChainstateActive().CoinsTip().DynamicMemoryUsage()) <=
	::ChainstateActive().m_coinstip_cache_size_bytes) {
	assert(coins.GetBestBlock() == pindex->GetBlockHash());
	DisconnectResult res =
	::ChainstateActive().DisconnectBlock(block, pindex, coins);
	if (res == DisconnectResult::FAILED) {
	return error("VerifyDB(): *** irrecoverable inconsistency in "
	"block data at %d, hash=%s",
	pindex->nHeight,
	pindex->GetBlockHash().ToString());
	}

	if (res == DisconnectResult::UNCLEAN) {
	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);
	}

	// store block count as we move pindex at check level >= 4
	int block_count = ::ChainActive().Height() - pindex->nHeight;

	// check level 4: try reconnecting blocks
	if (nCheckLevel >= 4) {
	while (pindex != ::ChainActive().Tip()) {
	const int percentageDone = std::max(
	1, std::min(99, 100 - int(double(::ChainActive().Height() -
	pindex->nHeight) /
	double(nCheckDepth) * 50)));
	if (reportDone < percentageDone / 10) {
	// report every 10% step
	LogPrintfToBeContinued("[%d%%]...", percentageDone);
	reportDone = percentageDone / 10;
	}
	uiInterface.ShowProgress(_("Verifying blocks...").translated,
	percentageDone, false);
	pindex = ::ChainActive().Next(pindex);
	CBlock block;
	if (!ReadBlockFromDisk(block, pindex, consensusParams)) {
	return error(
	"VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s",
	pindex->nHeight, pindex->GetBlockHash().ToString());
	}
	if (!::ChainstateActive().ConnectBlock(
	block, state, pindex, coins, params,
	BlockValidationOptions(config))) {
	return error("VerifyDB(): *** found unconnectable block at %d, "
	"hash=%s (%s)",
	pindex->nHeight, pindex->GetBlockHash().ToString(),
	state.ToString());
	}
	if (ShutdownRequested()) {
	return true;
	}
	}
	}

	LogPrintf("[DONE].\n");
	LogPrintf("No coin database inconsistencies in last %i blocks (%i "
	"transactions)\n",
	block_count, nGoodTransactions);

	return true;
	}

	/**
	* Apply the effects of a block on the utxo cache, ignoring that it may already
	* have been applied.
	*/
	bool CChainState::RollforwardBlock(const CBlockIndex *pindex,
	CCoinsViewCache &view,
	const Consensus::Params &params) {
	// TODO: merge with ConnectBlock
	CBlock block;
	if (!ReadBlockFromDisk(block, pindex, params)) {
	return error("ReplayBlock(): ReadBlockFromDisk failed at %d, hash=%s",
	pindex->nHeight, pindex->GetBlockHash().ToString());
	}

	for (const CTransactionRef &tx : block.vtx) {
	// Pass check = true as every addition may be an overwrite.
	AddCoins(view, *tx, pindex->nHeight, true);
	}

	for (const CTransactionRef &tx : block.vtx) {
	if (tx->IsCoinBase()) {
	continue;
	}

	for (const CTxIn &txin : tx->vin) {
	view.SpendCoin(txin.prevout);
	}
	}

	return true;
	}

	bool CChainState::ReplayBlocks(const Consensus::Params &params) {
	LOCK(cs_main);

	CCoinsView &db = this->CoinsDB();
	CCoinsViewCache cache(&db);

	std::vector<BlockHash> hashHeads = db.GetHeadBlocks();
	if (hashHeads.empty()) {
	// We're already in a consistent state.
	return true;
	}
	if (hashHeads.size() != 2) {
	return error("ReplayBlocks(): unknown inconsistent state");
	}

	uiInterface.ShowProgress(_("Replaying blocks...").translated, 0, false);
	LogPrintf("Replaying blocks\n");

	// Old tip during the interrupted flush.
	const CBlockIndex *pindexOld = nullptr;
	// New tip during the interrupted flush.
	const CBlockIndex *pindexNew;
	// Latest block common to both the old and the new tip.
	const CBlockIndex *pindexFork = nullptr;

	if (m_blockman.m_block_index.count(hashHeads[0]) == 0) {
	return error(
	"ReplayBlocks(): reorganization to unknown block requested");
	}

	pindexNew = m_blockman.m_block_index[hashHeads[0]];

	if (!hashHeads[1].IsNull()) {
	// The old tip is allowed to be 0, indicating it's the first flush.
	if (m_blockman.m_block_index.count(hashHeads[1]) == 0) {
	return error(
	"ReplayBlocks(): reorganization from unknown block requested");
	}

	pindexOld = m_blockman.m_block_index[hashHeads[1]];
	pindexFork = LastCommonAncestor(pindexOld, pindexNew);
	assert(pindexFork != nullptr);
	}

	// Rollback along the old branch.
	while (pindexOld != pindexFork) {
	if (pindexOld->nHeight > 0) {
	// Never disconnect the genesis block.
	CBlock block;
	if (!ReadBlockFromDisk(block, pindexOld, params)) {
	return error("RollbackBlock(): ReadBlockFromDisk() failed at "
	"%d, hash=%s",
	pindexOld->nHeight,
	pindexOld->GetBlockHash().ToString());
	}

	LogPrintf("Rolling back %s (%i)\n",
	pindexOld->GetBlockHash().ToString(), pindexOld->nHeight);
	DisconnectResult res = DisconnectBlock(block, pindexOld, cache);
	if (res == DisconnectResult::FAILED) {
	return error(
	"RollbackBlock(): DisconnectBlock failed at %d, hash=%s",
	pindexOld->nHeight, pindexOld->GetBlockHash().ToString());
	}

	// If DisconnectResult::UNCLEAN is returned, it means a non-existing
	// UTXO was deleted, or an existing UTXO was overwritten. It
	// corresponds to cases where the block-to-be-disconnect never had
	// all its operations applied to the UTXO set. However, as both
	// writing a UTXO and deleting a UTXO are idempotent operations, the
	// result is still a version of the UTXO set with the effects of
	// that block undone.
	}
	pindexOld = pindexOld->pprev;
	}

	// Roll forward from the forking point to the new tip.
	int nForkHeight = pindexFork ? pindexFork->nHeight : 0;
	for (int nHeight = nForkHeight + 1; nHeight <= pindexNew->nHeight;
	++nHeight) {
	const CBlockIndex *pindex = pindexNew->GetAncestor(nHeight);
	LogPrintf("Rolling forward %s (%i)\n",
	pindex->GetBlockHash().ToString(), nHeight);
	uiInterface.ShowProgress(_("Replaying blocks...").translated,
	(int)((nHeight - nForkHeight) * 100.0 /
	(pindexNew->nHeight - nForkHeight)),
	false);
	if (!RollforwardBlock(pindex, cache, params)) {
	return false;
	}
	}

	cache.SetBestBlock(pindexNew->GetBlockHash());
	cache.Flush();
	uiInterface.ShowProgress("", 100, 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 CChainState::UnloadBlockIndex() {
	nBlockSequenceId = 1;
	setBlockIndexCandidates.clear();

	// Do not point to CBlockIndex that will be free'd
	m_finalizedBlockIndex = nullptr;
	}

	// May NOT be used after any connections are up as much
	// of the peer-processing logic assumes a consistent
	// block index state
	void UnloadBlockIndex(CTxMemPool *mempool, ChainstateManager &chainman) {
	LOCK(cs_main);
	chainman.Unload();
	pindexBestInvalid = nullptr;
	pindexBestParked = nullptr;
	pindexBestHeader = nullptr;
	pindexBestForkTip = nullptr;
	pindexBestForkBase = nullptr;
	ResetASERTAnchorBlockCache();
	if (mempool) {
	mempool->clear();
	}
	vinfoBlockFile.clear();
	nLastBlockFile = 0;
	setDirtyBlockIndex.clear();
	setDirtyFileInfo.clear();
	fHavePruned = false;
	}

	bool ChainstateManager::LoadBlockIndex(const Consensus::Params &params) {
	AssertLockHeld(cs_main);
	// Load block index from databases
	bool needs_init = fReindex;
	if (!fReindex) {
	bool ret = LoadBlockIndexDB(*this, params);
	if (!ret) {
	return false;
	}

	needs_init = m_blockman.m_block_index.empty();
	}

	if (needs_init) {
	// Everything here is for new reindex/DBs. Thus, though
	// LoadBlockIndexDB may have set fReindex if we shut down
	// mid-reindex previously, we don't check fReindex and
	// instead only check it prior to LoadBlockIndexDB to set
	// needs_init.

	LogPrintf("Initializing databases...\n");
	}
	return true;
	}

	bool CChainState::LoadGenesisBlock(const CChainParams &chainparams) {
	LOCK(cs_main);

	// Check whether we're already initialized by checking for genesis in
	// m_blockman.m_block_index. Note that we can't use m_chain here, since it
	// is set based on the coins db, not the block index db, which is the only
	// thing loaded at this point.
	if (m_blockman.m_block_index.count(chainparams.GenesisBlock().GetHash())) {
	return true;
	}

	try {
	const CBlock &block = chainparams.GenesisBlock();
	FlatFilePos blockPos = SaveBlockToDisk(block, 0, chainparams, nullptr);
	if (blockPos.IsNull()) {
	return error("%s: writing genesis block to disk failed", __func__);
	}
	CBlockIndex *pindex = m_blockman.AddToBlockIndex(block);
	ReceivedBlockTransactions(block, pindex, blockPos);
	} catch (const std::runtime_error &e) {
	return error("%s: failed to write genesis block: %s", __func__,
	e.what());
	}

	return true;
	}

	bool LoadGenesisBlock(const CChainParams &chainparams) {
	return ::ChainstateActive().LoadGenesisBlock(chainparams);
	}

	void LoadExternalBlockFile(const Config &config, FILE *fileIn,
	FlatFilePos *dbp) {
	// Map of disk positions for blocks with unknown parent (only used for
	// reindex)
	static std::multimap<uint256, FlatFilePos> 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()) {
	if (ShutdownRequested()) {
	return;
	}

	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.
	uint8_t buf[CMessageHeader::MESSAGE_START_SIZE];
	blkdat.FindByte(chainparams.DiskMagic()[0]);
	nRewind = blkdat.GetPos() + 1;
	blkdat >> buf;
	if (memcmp(buf, chainparams.DiskMagic().data(),
	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);
	std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
	CBlock &block = *pblock;
	blkdat >> block;
	nRewind = blkdat.GetPos();

	const BlockHash hash = block.GetHash();
	{
	LOCK(cs_main);
	// detect out of order blocks, and store them for later
	if (hash != chainparams.GetConsensus().hashGenesisBlock &&
	!LookupBlockIndex(block.hashPrevBlock)) {
	LogPrint(
	BCLog::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
	CBlockIndex *pindex = LookupBlockIndex(hash);
	if (!pindex \|\| !pindex->nStatus.hasData()) {
	BlockValidationState state;
	if (::ChainstateActive().AcceptBlock(
	config, pblock, state, true, dbp, nullptr)) {
	nLoaded++;
	}
	if (state.IsError()) {
	break;
	}
	} else if (hash != chainparams.GetConsensus()
	.hashGenesisBlock &&
	pindex->nHeight % 1000 == 0) {
	LogPrint(
	BCLog::REINDEX,
	"Block Import: already had block %s at height %d\n",
	hash.ToString(), pindex->nHeight);
	}
	}

	// Activate the genesis block so normal node progress can
	// continue
	if (hash == chainparams.GetConsensus().hashGenesisBlock) {
	BlockValidationState state;
	if (!ActivateBestChain(config, state, nullptr)) {
	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, FlatFilePos>::iterator,
	std::multimap<uint256, FlatFilePos>::iterator>
	range = mapBlocksUnknownParent.equal_range(head);
	while (range.first != range.second) {
	std::multimap<uint256, FlatFilePos>::iterator it =
	range.first;
	std::shared_ptr<CBlock> pblockrecursive =
	std::make_shared<CBlock>();
	if (ReadBlockFromDisk(*pblockrecursive, it->second,
	chainparams.GetConsensus())) {
	LogPrint(
	BCLog::REINDEX,
	"%s: Processing out of order child %s of %s\n",
	__func__, pblockrecursive->GetHash().ToString(),
	head.ToString());
	LOCK(cs_main);
	BlockValidationState dummy;
	if (::ChainstateActive().AcceptBlock(
	config, pblockrecursive, dummy, 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());
	}

	LogPrintf("Loaded %i blocks from external file in %dms\n", nLoaded,
	GetTimeMillis() - nStart);
	}

	void CChainState::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
	// m_blockman.m_block_index but no active chain. (A few of the tests when
	// iterating the block tree require that m_chain has been initialized.)
	if (m_chain.Height() < 0) {
	assert(m_blockman.m_block_index.size() <= 1);
	return;
	}

	// Build forward-pointing map of the entire block tree.
	std::multimap<CBlockIndex , CBlockIndex > forward;
	for (const auto &entry : m_blockman.m_block_index) {
	forward.emplace(entry.second->pprev, entry.second);
	}

	assert(forward.size() == m_blockman.m_block_index.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 is parked.
	CBlockIndex *pindexFirstParked = nullptr;
	// Oldest ancestor of pindex which does not have data available.
	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.hasFailed()) {
	pindexFirstInvalid = pindex;
	}
	if (pindexFirstParked == nullptr && pindex->nStatus.isParked()) {
	pindexFirstParked = pindex;
	}
	if (pindexFirstMissing == nullptr && !pindex->nStatus.hasData()) {
	pindexFirstMissing = pindex;
	}
	if (pindexFirstNeverProcessed == nullptr && pindex->nTx == 0) {
	pindexFirstNeverProcessed = pindex;
	}
	if (pindex->pprev != nullptr && pindexFirstNotTreeValid == nullptr &&
	pindex->nStatus.getValidity() < BlockValidity::TREE) {
	pindexFirstNotTreeValid = pindex;
	}
	if (pindex->pprev != nullptr &&
	pindexFirstNotTransactionsValid == nullptr &&
	pindex->nStatus.getValidity() < BlockValidity::TRANSACTIONS) {
	pindexFirstNotTransactionsValid = pindex;
	}
	if (pindex->pprev != nullptr && pindexFirstNotChainValid == nullptr &&
	pindex->nStatus.getValidity() < BlockValidity::CHAIN) {
	pindexFirstNotChainValid = pindex;
	}
	if (pindex->pprev != nullptr && pindexFirstNotScriptsValid == nullptr &&
	pindex->nStatus.getValidity() < BlockValidity::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 == m_chain.Genesis());
	}
	if (!pindex->HaveTxsDownloaded()) {
	// 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.hasData() == (pindex->nTx > 0));
	assert(pindexFirstMissing == pindexFirstNeverProcessed);
	} else if (pindex->nStatus.hasData()) {
	// If we have pruned, then we can only say that HAVE_DATA implies
	// nTx > 0
	assert(pindex->nTx > 0);
	}
	if (pindex->nStatus.hasUndo()) {
	assert(pindex->nStatus.hasData());
	}
	// This is pruning-independent.
	assert((pindex->nStatus.getValidity() >= BlockValidity::TRANSACTIONS) ==
	(pindex->nTx > 0));
	// All parents having had data (at some point) is equivalent to all
	// parents being VALID_TRANSACTIONS, which is equivalent to
	// HaveTxsDownloaded(). All parents having had data (at some point) is
	// equivalent to all parents being VALID_TRANSACTIONS, which is
	// equivalent to HaveTxsDownloaded().
	assert((pindexFirstNeverProcessed == nullptr) ==
	(pindex->HaveTxsDownloaded()));
	assert((pindexFirstNotTransactionsValid == nullptr) ==
	(pindex->HaveTxsDownloaded()));
	// 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 m_blockman.m_block_index entries must at least be TREE valid
	assert(pindexFirstNotTreeValid == nullptr);
	if (pindex->nStatus.getValidity() >= BlockValidity::TREE) {
	// TREE valid implies all parents are TREE valid
	assert(pindexFirstNotTreeValid == nullptr);
	}
	if (pindex->nStatus.getValidity() >= BlockValidity::CHAIN) {
	// CHAIN valid implies all parents are CHAIN valid
	assert(pindexFirstNotChainValid == nullptr);
	}
	if (pindex->nStatus.getValidity() >= BlockValidity::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.isInvalid());
	}
	if (pindexFirstParked == nullptr) {
	// Checks for not-parked blocks.
	// The parked mask cannot be set for blocks without parked parents.
	// (i.e., hasParkedParent only if an ancestor is properly parked).
	assert(!pindex->nStatus.isOnParkedChain());
	}
	if (!CBlockIndexWorkComparator()(pindex, m_chain.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 or be parked.
	if (pindexFirstMissing == nullptr) {
	assert(pindex->nStatus.isOnParkedChain() \|\|
	setBlockIndexCandidates.count(pindex));
	}
	// m_chain.Tip() must also be there even if some data has
	// been pruned.
	if (pindex == m_chain.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
	// m_blocks_unlinked -- 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 m_blocks_unlinked.
	std::pair<std::multimap<CBlockIndex , CBlockIndex >::iterator,
	std::multimap<CBlockIndex , CBlockIndex >::iterator>
	rangeUnlinked =
	m_blockman.m_blocks_unlinked.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.hasData() &&
	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
	// m_blocks_unlinked.
	assert(foundInUnlinked);
	}
	if (!pindex->nStatus.hasData()) {
	// Can't be in m_blocks_unlinked if we don't HAVE_DATA
	assert(!foundInUnlinked);
	}
	if (pindexFirstMissing == nullptr) {
	// We aren't missing data for any parent -- cannot be in
	// m_blocks_unlinked.
	assert(!foundInUnlinked);
	}
	if (pindex->pprev && pindex->nStatus.hasData() &&
	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 m_blocks_unlinked 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 m_chain and the
	// tip.
	// So if this block is itself better than m_chain.Tip() and it
	// wasn't in
	// setBlockIndexCandidates, then it must be in m_blocks_unlinked.
	if (!CBlockIndexWorkComparator()(pindex, m_chain.Tip()) &&
	setBlockIndexCandidates.count(pindex) == 0) {
	if (pindexFirstInvalid == nullptr) {
	assert(foundInUnlinked);
	}
	}
	}
	// Perhaps too slow
	// assert(pindex->GetBlockHash() == pindex->GetBlockHeader().GetHash());
	// 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 == pindexFirstParked) {
	pindexFirstParked = 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 CChainState::ToString() {
	CBlockIndex *tip = m_chain.Tip();
	return strprintf("Chainstate [%s] @ height %d (%s)",
	m_from_snapshot_blockhash.IsNull() ? "ibd" : "snapshot",
	tip ? tip->nHeight : -1,
	tip ? tip->GetBlockHash().ToString() : "null");
	}

	bool CChainState::ResizeCoinsCaches(size_t coinstip_size, size_t coinsdb_size) {
	if (coinstip_size == m_coinstip_cache_size_bytes &&
	coinsdb_size == m_coinsdb_cache_size_bytes) {
	// Cache sizes are unchanged, no need to continue.
	return true;
	}
	size_t old_coinstip_size = m_coinstip_cache_size_bytes;
	m_coinstip_cache_size_bytes = coinstip_size;
	m_coinsdb_cache_size_bytes = coinsdb_size;
	CoinsDB().ResizeCache(coinsdb_size);

	LogPrintf("[%s] resized coinsdb cache to %.1f MiB\n", this->ToString(),
	coinsdb_size * (1.0 / 1024 / 1024));
	LogPrintf("[%s] resized coinstip cache to %.1f MiB\n", this->ToString(),
	coinstip_size * (1.0 / 1024 / 1024));

	BlockValidationState state;
	const CChainParams &chainparams = Params();

	bool ret;

	if (coinstip_size > old_coinstip_size) {
	// Likely no need to flush if cache sizes have grown.
	ret = FlushStateToDisk(chainparams, state, FlushStateMode::IF_NEEDED);
	} else {
	// Otherwise, flush state to disk and deallocate the in-memory coins
	// map.
	ret = FlushStateToDisk(chainparams, state, FlushStateMode::ALWAYS);
	CoinsTip().ReallocateCache();
	}
	return ret;
	}

	std::string CBlockFileInfo::ToString() const {
	return strprintf(
	"CBlockFileInfo(blocks=%u, size=%u, heights=%u...%u, time=%s...%s)",
	nBlocks, nSize, nHeightFirst, nHeightLast,
	FormatISO8601DateTime(nTimeFirst), FormatISO8601DateTime(nTimeLast));
	}

	CBlockFileInfo *GetBlockFileInfo(size_t n) {
	LOCK(cs_LastBlockFile);

	return &vinfoBlockFile.at(n);
	}

	static ThresholdState VersionBitsStateImpl(const Consensus::Params &params,
	Consensus::DeploymentPos pos,
	const CBlockIndex *pindex)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
	return VersionBitsState(pindex, params, pos, versionbitscache);
	}

	ThresholdState VersionBitsTipState(const Consensus::Params &params,
	Consensus::DeploymentPos pos) {
	LOCK(cs_main);
	return VersionBitsStateImpl(params, pos, ::ChainActive().Tip());
	}

	ThresholdState VersionBitsBlockState(const Consensus::Params &params,
	Consensus::DeploymentPos pos,
	const CBlockIndex *pindex) {
	LOCK(cs_main);
	return VersionBitsStateImpl(params, pos, pindex);
	}

	BIP9Stats VersionBitsTipStatistics(const Consensus::Params &params,
	Consensus::DeploymentPos pos) {
	LOCK(cs_main);
	return VersionBitsStatistics(::ChainActive().Tip(), params, pos);
	}

	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, CTxMemPool &pool) {
	int64_t nExpiryTimeout =
	gArgs.GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60;
	FILE *filestr = fsbridge::fopen(GetDataDir() / "mempool.dat", "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 expired = 0;
	int64_t failed = 0;
	int64_t already_there = 0;
	int64_t unbroadcast = 0;
	int64_t nNow = GetTime();

	try {
	uint64_t version;
	file >> version;
	if (version != MEMPOOL_DUMP_VERSION) {
	return false;
	}

	uint64_t num;
	file >> num;
	while (num--) {
	CTransactionRef tx;
	int64_t nTime;
	int64_t nFeeDelta;
	file >> tx;
	file >> nTime;
	file >> nFeeDelta;

	Amount amountdelta = nFeeDelta * SATOSHI;
	if (amountdelta != Amount::zero()) {
	pool.PrioritiseTransaction(tx->GetId(), amountdelta);
	}
	TxValidationState state;
	if (nTime > nNow - nExpiryTimeout) {
	LOCK(cs_main);
	AcceptToMemoryPoolWithTime(config, pool, state, tx, nTime,
	false /* bypass_limits */,
	false /* test_accept */);
	if (state.IsValid()) {
	++count;
	} else {
	// mempool may contain the transaction already, e.g. from
	// wallet(s) having loaded it while we were processing
	// mempool transactions; consider these as valid, instead of
	// failed, but mark them as 'already there'
	if (pool.exists(tx->GetId())) {
	++already_there;
	} else {
	++failed;
	}
	}
	} else {
	++expired;
	}

	if (ShutdownRequested()) {
	return false;
	}
	}
	std::map<TxId, Amount> mapDeltas;
	file >> mapDeltas;

	for (const auto &i : mapDeltas) {
	pool.PrioritiseTransaction(i.first, i.second);
	}

	// TODO: remove this try...catch after May 15th 2021,
	// when no one is running v0.22.11 or lower anymore.
	// This will be done by backporting PR20854.
	try {
	std::set<TxId> unbroadcast_txids;
	file >> unbroadcast_txids;
	unbroadcast = unbroadcast_txids.size();
	for (const auto &txid : unbroadcast_txids) {
	pool.AddUnbroadcastTx(txid);
	}
	} catch (const std::exception &) {
	// mempool.dat files created prior to v0.22.12 will not have an
	// unbroadcast set. No need to log a failure if parsing fails here.
	}

	} 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 succeeded, %i "
	"failed, %i expired, %i already there, %i waiting for initial "
	"broadcast\n",
	count, failed, expired, already_there, unbroadcast);
	return true;
	}

	bool DumpMempool(const CTxMemPool &pool) {
	int64_t start = GetTimeMicros();

	std::map<uint256, Amount> mapDeltas;
	std::vector<TxMempoolInfo> vinfo;
	std::set<TxId> unbroadcast_txids;

	static Mutex dump_mutex;
	LOCK(dump_mutex);

	{
	LOCK(pool.cs);
	for (const auto &i : pool.mapDeltas) {
	mapDeltas[i.first] = i.second;
	}

	vinfo = pool.infoAll();
	unbroadcast_txids = pool.GetUnbroadcastTxs();
	}

	int64_t mid = GetTimeMicros();

	try {
	FILE *filestr = fsbridge::fopen(GetDataDir() / "mempool.dat.new", "wb");
	if (!filestr) {
	return false;
	}

	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(count_seconds(i.m_time));
	file << i.nFeeDelta;
	mapDeltas.erase(i.tx->GetId());
	}

	file << mapDeltas;

	LogPrintf("Writing %d unbroadcast transactions to disk.\n",
	unbroadcast_txids.size());
	file << unbroadcast_txids;

	if (!FileCommit(file.Get())) {
	throw std::runtime_error("FileCommit failed");
	}
	file.fclose();
	if (!RenameOver(GetDataDir() / "mempool.dat.new",
	GetDataDir() / "mempool.dat")) {
	throw std::runtime_error("Rename failed");
	}
	int64_t last = GetTimeMicros();
	LogPrintf("Dumped mempool: %gs to copy, %gs to dump\n",
	(mid - start) * MICRO, (last - mid) * MICRO);
	} catch (const std::exception &e) {
	LogPrintf("Failed to dump mempool: %s. Continuing anyway.\n", e.what());
	return false;
	}
	return true;
	}

	bool IsBlockPruned(const CBlockIndex *pblockindex) {
	return (fHavePruned && !pblockindex->nStatus.hasData() &&
	pblockindex->nTx > 0);
	}

	//! Guess how far we are in the verification process at the given block index
	//! require cs_main if pindex has not been validated yet (because the chain's
	//! transaction count might be unset) This conditional lock requirement might be
	//! confusing, see: https://github.com/bitcoin/bitcoin/issues/15994
	double GuessVerificationProgress(const ChainTxData &data,
	const CBlockIndex *pindex) {
	if (pindex == nullptr) {
	return 0.0;
	}

	int64_t nNow = time(nullptr);

	double fTxTotal;
	if (pindex->GetChainTxCount() <= data.nTxCount) {
	fTxTotal = data.nTxCount + (nNow - data.nTime) * data.dTxRate;
	} else {
	fTxTotal = pindex->GetChainTxCount() +
	(nNow - pindex->GetBlockTime()) * data.dTxRate;
	}

	return std::min<double>(pindex->GetChainTxCount() / fTxTotal, 1.0);
	}

	std::optional<BlockHash> ChainstateManager::SnapshotBlockhash() const {
	if (m_active_chainstate != nullptr) {
	// If a snapshot chainstate exists, it will always be our active.
	return m_active_chainstate->m_from_snapshot_blockhash;
	}
	return {};
	}

	std::vector<CChainState *> ChainstateManager::GetAll() {
	std::vector<CChainState *> out;

	if (!IsSnapshotValidated() && m_ibd_chainstate) {
	out.push_back(m_ibd_chainstate.get());
	}

	if (m_snapshot_chainstate) {
	out.push_back(m_snapshot_chainstate.get());
	}

	return out;
	}

	CChainState &
	ChainstateManager::InitializeChainstate(CTxMemPool &mempool,
	const BlockHash &snapshot_blockhash) {
	bool is_snapshot = !snapshot_blockhash.IsNull();
	std::unique_ptr<CChainState> &to_modify =
	is_snapshot ? m_snapshot_chainstate : m_ibd_chainstate;

	if (to_modify) {
	throw std::logic_error("should not be overwriting a chainstate");
	}
	to_modify.reset(new CChainState(mempool, m_blockman, snapshot_blockhash));

	// Snapshot chainstates and initial IBD chaintates always become active.
	if (is_snapshot \|\| (!is_snapshot && !m_active_chainstate)) {
	LogPrintf("Switching active chainstate to %s\n", to_modify->ToString());
	m_active_chainstate = to_modify.get();
	} else {
	throw std::logic_error("unexpected chainstate activation");
	}

	return *to_modify;
	}

	CChainState &ChainstateManager::ActiveChainstate() const {
	assert(m_active_chainstate);
	return *m_active_chainstate;
	}

	bool ChainstateManager::IsSnapshotActive() const {
	return m_snapshot_chainstate &&
	m_active_chainstate == m_snapshot_chainstate.get();
	}

	CChainState &ChainstateManager::ValidatedChainstate() const {
	if (m_snapshot_chainstate && IsSnapshotValidated()) {
	return *m_snapshot_chainstate.get();
	}
	assert(m_ibd_chainstate);
	return *m_ibd_chainstate.get();
	}

	bool ChainstateManager::IsBackgroundIBD(CChainState *chainstate) const {
	return (m_snapshot_chainstate && chainstate == m_ibd_chainstate.get());
	}

	void ChainstateManager::Unload() {
	for (CChainState *chainstate : this->GetAll()) {
	chainstate->m_chain.SetTip(nullptr);
	chainstate->UnloadBlockIndex();
	}

	m_blockman.Unload();
	}

	void ChainstateManager::Reset() {
	m_ibd_chainstate.reset();
	m_snapshot_chainstate.reset();
	m_active_chainstate = nullptr;
	m_snapshot_validated = false;
	}

	void ChainstateManager::MaybeRebalanceCaches() {
	if (m_ibd_chainstate && !m_snapshot_chainstate) {
	LogPrintf("[snapshot] allocating all cache to the IBD chainstate\n");
	// Allocate everything to the IBD chainstate.
	m_ibd_chainstate->ResizeCoinsCaches(m_total_coinstip_cache,
	m_total_coinsdb_cache);
	} else if (m_snapshot_chainstate && !m_ibd_chainstate) {
	LogPrintf(
	"[snapshot] allocating all cache to the snapshot chainstate\n");
	// Allocate everything to the snapshot chainstate.
	m_snapshot_chainstate->ResizeCoinsCaches(m_total_coinstip_cache,
	m_total_coinsdb_cache);
	} else if (m_ibd_chainstate && m_snapshot_chainstate) {
	// If both chainstates exist, determine who needs more cache based on
	// IBD status.
	//
	// Note: shrink caches first so that we don't inadvertently overwhelm
	// available memory.
	if (m_snapshot_chainstate->IsInitialBlockDownload()) {
	m_ibd_chainstate->ResizeCoinsCaches(m_total_coinstip_cache * 0.05,
	m_total_coinsdb_cache * 0.05);
	m_snapshot_chainstate->ResizeCoinsCaches(
	m_total_coinstip_cache * 0.95, m_total_coinsdb_cache * 0.95);
	} else {
	m_snapshot_chainstate->ResizeCoinsCaches(
	m_total_coinstip_cache * 0.05, m_total_coinsdb_cache * 0.05);
	m_ibd_chainstate->ResizeCoinsCaches(m_total_coinstip_cache * 0.95,
	m_total_coinsdb_cache * 0.95);
	}
	}
	}
	diff --git a/src/validation.h b/src/validation.h
	index 04d99488c..6b8402654 100644
	--- a/src/validation.h
	+++ b/src/validation.h
	@@ -1,1319 +1,1324 @@
	// Copyright (c) 2009-2010 Satoshi Nakamoto
	// Copyright (c) 2009-2019 The Bitcoin Core developers
	// Copyright (c) 2017-2020 The Bitcoin developers
	// Distributed under the MIT software license, see the accompanying
	// file COPYING or http://www.opensource.org/licenses/mit-license.php.

	#ifndef BITCOIN_VALIDATION_H
	#define BITCOIN_VALIDATION_H

	#if defined(HAVE_CONFIG_H)
	#include <config/bitcoin-config.h>
	#endif

	#include <amount.h>
	#include <blockfileinfo.h>
	#include <blockindexworkcomparator.h>
	#include <coins.h>
	#include <consensus/consensus.h>
	#include <disconnectresult.h>
	#include <flatfile.h>
	#include <fs.h>
	#include <protocol.h> // For CMessageHeader::MessageMagic
	#include <script/script_error.h>
	#include <script/script_metrics.h>
	#include <sync.h>
	#include <txdb.h>
	#include <txmempool.h> // For CTxMemPool::cs
	#include <versionbits.h>

	#include <atomic>
	#include <cstdint>
	#include <map>
	#include <memory>
	#include <optional>
	#include <set>
	#include <string>
	#include <utility>
	#include <vector>

	class BlockValidationState;
	class CBlockIndex;
	class CBlockTreeDB;
	class CBlockUndo;
	class CChainParams;
	class CChain;
	class CChainState;
	class CConnman;
	class CInv;
	class ChainstateManager;
	class Config;
	class CScriptCheck;
	class CTxMemPool;
	class CTxUndo;
	class DisconnectedBlockTransactions;
	class TxValidationState;

	struct ChainTxData;
	struct FlatFilePos;
	struct PrecomputedTransactionData;
	struct LockPoints;

	namespace Consensus {
	struct Params;
	}

	#define MIN_TRANSACTION_SIZE \
	(::GetSerializeSize(CTransaction(), PROTOCOL_VERSION))

	/** Default for -minrelaytxfee, minimum relay fee for transactions */
	static const Amount DEFAULT_MIN_RELAY_TX_FEE_PER_KB(1000 * SATOSHI);
	/** Default for -excessutxocharge for transactions transactions */
	static const Amount DEFAULT_UTXO_FEE = Amount::zero();
	/**
	* Default for -mempoolexpiry, expiration time for mempool transactions in
	* hours.
	*/
	static const unsigned int DEFAULT_MEMPOOL_EXPIRY = 336;
	/** The maximum size of a blk?????.dat file (since 0.8) */
	static const unsigned int MAX_BLOCKFILE_SIZE = 0x8000000; // 128 MiB
	/** Maximum number of dedicated script-checking threads allowed */
	static const int MAX_SCRIPTCHECK_THREADS = 15;
	/** -par default (number of script-checking threads, 0 = auto) */
	static const int DEFAULT_SCRIPTCHECK_THREADS = 0;
	static const int64_t DEFAULT_MAX_TIP_AGE = 24 * 60 * 60;
	static const bool DEFAULT_CHECKPOINTS_ENABLED = true;
	static const bool DEFAULT_TXINDEX = false;
	static const char *const DEFAULT_BLOCKFILTERINDEX = "0";

	/** Default for -persistmempool */
	static const bool DEFAULT_PERSIST_MEMPOOL = true;
	/** Default for using fee filter */
	static const bool DEFAULT_FEEFILTER = true;

	static const bool DEFAULT_PEERBLOOMFILTERS = true;

	/** Default for -stopatheight */
	static const int DEFAULT_STOPATHEIGHT = 0;
	/** Default for -maxreorgdepth */
	static const int DEFAULT_MAX_REORG_DEPTH = 10;
	/**
	* Default for -finalizationdelay
	* This is the minimum time between a block header reception and the block
	* finalization.
	* This value should be >> block propagation and validation time
	*/
	static const int64_t DEFAULT_MIN_FINALIZATION_DELAY = 2 * 60 * 60;
	/**
	* Block files containing a block-height within MIN_BLOCKS_TO_KEEP of
	* ::ChainActive().Tip() will not be pruned.
	*/
	static const unsigned int MIN_BLOCKS_TO_KEEP = 288;
	static const signed int DEFAULT_CHECKBLOCKS = 6;
	static const unsigned int DEFAULT_CHECKLEVEL = 3;
	/**
	* Require that user allocate at least 550 MiB for block & undo files
	* (blk???.dat and rev???.dat)
	* At 1MB per block, 288 blocks = 288MB.
	* Add 15% for Undo data = 331MB
	* Add 20% for Orphan block rate = 397MB
	* We want the low water mark after pruning to be at least 397 MB and since we
	* prune in full block file chunks, we need the high water mark which triggers
	* the prune to be one 128MB block file + added 15% undo data = 147MB greater
	* for a total of 545MB
	* Setting the target to >= 550 MiB will make it likely we can respect the
	* target.
	*/
	static const uint64_t MIN_DISK_SPACE_FOR_BLOCK_FILES = 550 * 1024 * 1024;

	/** Current sync state passed to tip changed callbacks. */
	enum class SynchronizationState { INIT_REINDEX, INIT_DOWNLOAD, POST_INIT };

	extern RecursiveMutex cs_main;
	typedef std::unordered_map<BlockHash, CBlockIndex *, BlockHasher> BlockMap;
	extern Mutex g_best_block_mutex;
	extern std::condition_variable g_best_block_cv;
	extern uint256 g_best_block;
	extern std::atomic_bool fImporting;
	extern std::atomic_bool fReindex;
	extern bool fRequireStandard;
	extern bool fCheckBlockIndex;
	extern bool fCheckpointsEnabled;

	/**
	* A fee rate smaller than this is considered zero fee (for relaying, mining and
	* transaction creation)
	*/
	extern CFeeRate minRelayTxFee;
	/**
	* If the tip is older than this (in seconds), the node is considered to be in
	* initial block download.
	*/
	extern int64_t nMaxTipAge;

	/**
	* Block hash whose ancestors we will assume to have valid scripts without
	* checking them.
	*/
	extern BlockHash hashAssumeValid;

	/**
	* Minimum work we will assume exists on some valid chain.
	*/
	extern arith_uint256 nMinimumChainWork;

	/**
	* Best header we've seen so far (used for getheaders queries' starting points).
	*/
	extern CBlockIndex *pindexBestHeader;

	/** Pruning-related variables and constants */
	/** True if any block files have ever been pruned. */
	extern bool fHavePruned;
	/** True if we're running in -prune mode. */
	extern bool fPruneMode;
	/** Number of MiB of block files that we're trying to stay below. */
	extern uint64_t nPruneTarget;
	/** Documentation for argument 'checklevel'. */
	extern const std::vector<std::string> CHECKLEVEL_DOC;

	class BlockValidationOptions {
	private:
	uint64_t excessiveBlockSize;
	bool checkPoW : 1;
	bool checkMerkleRoot : 1;

	public:
	// Do full validation by default
	explicit BlockValidationOptions(const Config &config);
	explicit BlockValidationOptions(uint64_t _excessiveBlockSize,
	bool _checkPow = true,
	bool _checkMerkleRoot = true)
	: excessiveBlockSize(_excessiveBlockSize), checkPoW(_checkPow),
	checkMerkleRoot(_checkMerkleRoot) {}

	BlockValidationOptions withCheckPoW(bool _checkPoW = true) const {
	BlockValidationOptions ret = *this;
	ret.checkPoW = _checkPoW;
	return ret;
	}

	BlockValidationOptions
	withCheckMerkleRoot(bool _checkMerkleRoot = true) const {
	BlockValidationOptions ret = *this;
	ret.checkMerkleRoot = _checkMerkleRoot;
	return ret;
	}

	bool shouldValidatePoW() const { return checkPoW; }
	bool shouldValidateMerkleRoot() const { return checkMerkleRoot; }
	uint64_t getExcessiveBlockSize() const { return excessiveBlockSize; }
	};

	/**
	* Import blocks from an external file.
	*/
	void LoadExternalBlockFile(const Config &config, FILE *fileIn,
	FlatFilePos *dbp = nullptr);

	/**
	* Ensures we have a genesis block in the block tree, possibly writing one to
	* disk.
	*/
	bool LoadGenesisBlock(const CChainParams &chainparams);

	/**
	* Unload database information.
	*/
	void UnloadBlockIndex(CTxMemPool *mempool, ChainstateManager &chainman);

	/**
	- * Run an instance of the script checking thread.
	+ * Run instances of script checking worker threads
	*/
	-void ThreadScriptCheck(int worker_num);
	+void StartScriptCheckWorkerThreads(int threads_num);
	+
	+/**
	+ * Stop all of the script checking worker threads
	+ */
	+void StopScriptCheckWorkerThreads();

	/**
	* Return transaction from the block at block_index.
	* If block_index is not provided, fall back to mempool.
	* If mempool is not provided or the tx couldn't be found in mempool, fall back
	* to g_txindex.
	*
	* @param[in] block_index The block to read from disk, or nullptr
	* @param[in] mempool If block_index is not provided, look in the
	* mempool, if provided
	* @param[in] txid The txid
	* @param[in] consensusParams The params
	* @param[out] hashBlock The hash of block_index, if the tx was found via
	* block_index
	* @returns The tx if found, otherwise nullptr
	*/
	CTransactionRef GetTransaction(const CBlockIndex *const block_index,
	const CTxMemPool *const mempool,
	const TxId &txid,
	const Consensus::Params &consensusParams,
	BlockHash &hashBlock);
	/**
	* Find the best known block, and make it the tip of the block chain
	*
	* May not be called with cs_main held. May not be called in a
	* validationinterface callback.
	*/
	bool ActivateBestChain(
	const Config &config, BlockValidationState &state,
	std::shared_ptr<const CBlock> pblock = std::shared_ptr<const CBlock>());
	Amount GetBlockSubsidy(int nHeight, const Consensus::Params &consensusParams);

	/**
	* Guess verification progress (as a fraction between 0.0=genesis and
	* 1.0=current tip).
	*/
	double GuessVerificationProgress(const ChainTxData &data,
	const CBlockIndex *pindex);

	/**
	* Calculate the amount of disk space the block & undo files currently use.
	*/
	uint64_t CalculateCurrentUsage();

	/**
	* Actually unlink the specified files
	*/
	void UnlinkPrunedFiles(const std::set<int> &setFilesToPrune);

	/** Prune block files up to a given height */
	void PruneBlockFilesManual(int nManualPruneHeight);

	/**
	* (try to) add transaction to memory pool
	* @param[out] fee_out optional argument to return tx fee to the caller
	*/
	bool AcceptToMemoryPool(const Config &config, CTxMemPool &pool,
	TxValidationState &state, const CTransactionRef &tx,
	bool bypass_limits, bool test_accept = false,
	Amount *fee_out = nullptr)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	/**
	* Simple class for regulating resource usage during CheckInputScripts (and
	* CScriptCheck), atomic so as to be compatible with parallel validation.
	*/
	class CheckInputsLimiter {
	protected:
	std::atomic<int64_t> remaining;

	public:
	explicit CheckInputsLimiter(int64_t limit) : remaining(limit) {}

	bool consume_and_check(int consumed) {
	auto newvalue = (remaining -= consumed);
	return newvalue >= 0;
	}

	bool check() { return remaining >= 0; }
	};

	class TxSigCheckLimiter : public CheckInputsLimiter {
	public:
	TxSigCheckLimiter() : CheckInputsLimiter(MAX_TX_SIGCHECKS) {}

	// Let's make this bad boy copiable.
	TxSigCheckLimiter(const TxSigCheckLimiter &rhs)
	: CheckInputsLimiter(rhs.remaining.load()) {}

	TxSigCheckLimiter &operator=(const TxSigCheckLimiter &rhs) {
	remaining = rhs.remaining.load();
	return *this;
	}

	static TxSigCheckLimiter getDisabled() {
	TxSigCheckLimiter txLimiter;
	// Historically, there has not been a transaction with more than 20k sig
	// checks on testnet or mainnet, so this effectively disable sigchecks.
	txLimiter.remaining = 20000;
	return txLimiter;
	}
	};

	class ConnectTrace;

	/**
	* Check whether all of this transaction's input scripts succeed.
	*
	* This involves ECDSA signature checks so can be computationally intensive.
	* This function should only be called after the cheap sanity checks in
	* CheckTxInputs passed.
	*
	* If pvChecks is not nullptr, script checks are pushed onto it instead of being
	* performed inline. Any script checks which are not necessary (eg due to script
	* execution cache hits) are, obviously, not pushed onto pvChecks/run.
	*
	* Upon success nSigChecksOut will be filled in with either:
	* - correct total for all inputs, or,
	* - 0, in the case when checks were pushed onto pvChecks (i.e., a cache miss
	* with pvChecks non-null), in which case the total can be found by executing
	* pvChecks and adding the results.
	*
	* Setting sigCacheStore/scriptCacheStore to false will remove elements from the
	* corresponding cache which are matched. This is useful for checking blocks
	* where we will likely never need the cache entry again.
	*
	* pLimitSigChecks can be passed to limit the sigchecks count either in parallel
	* or serial validation. With pvChecks null (serial validation), breaking the
	* pLimitSigChecks limit will abort evaluation early and return false. With
	* pvChecks not-null (parallel validation): the cached nSigChecks may itself
	* break the limit in which case false is returned, OR, each entry in the
	* returned pvChecks must be executed exactly once in order to probe the limit
	* accurately.
	*/
	bool CheckInputScripts(const CTransaction &tx, TxValidationState &state,
	const CCoinsViewCache &view, const uint32_t flags,
	bool sigCacheStore, bool scriptCacheStore,
	const PrecomputedTransactionData &txdata,
	int &nSigChecksOut, TxSigCheckLimiter &txLimitSigChecks,
	CheckInputsLimiter *pBlockLimitSigChecks,
	std::vector<CScriptCheck> *pvChecks)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	/**
	* Handy shortcut to full fledged CheckInputScripts call.
	*/
	static inline bool
	CheckInputScripts(const CTransaction &tx, TxValidationState &state,
	const CCoinsViewCache &view, const uint32_t flags,
	bool sigCacheStore, bool scriptCacheStore,
	const PrecomputedTransactionData &txdata, int &nSigChecksOut)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
	TxSigCheckLimiter nSigChecksTxLimiter;
	return CheckInputScripts(tx, state, view, flags, sigCacheStore,
	scriptCacheStore, txdata, nSigChecksOut,
	nSigChecksTxLimiter, nullptr, nullptr);
	}

	/** Get the BIP9 state for a given deployment at the current tip. */
	ThresholdState VersionBitsTipState(const Consensus::Params &params,
	Consensus::DeploymentPos pos);

	/** Get the BIP9 state for a given deployment at a given block. */
	ThresholdState VersionBitsBlockState(const Consensus::Params &params,
	Consensus::DeploymentPos pos,
	const CBlockIndex *pindex);

	/**
	* Get the numerical statistics for the BIP9 state for a given deployment at the
	* current tip.
	*/
	BIP9Stats VersionBitsTipStatistics(const Consensus::Params &params,
	Consensus::DeploymentPos pos);

	/**
	* Get the block height at which the BIP9 deployment switched into the state for
	* the block building on the current tip.
	*/
	int VersionBitsTipStateSinceHeight(const Consensus::Params &params,
	Consensus::DeploymentPos pos);

	/** Apply the effects of this transaction on the UTXO set represented by view */
	void UpdateCoins(const CTransaction &tx, CCoinsViewCache &inputs, int nHeight);

	/**
	* Mark all the coins corresponding to a given transaction inputs as spent.
	*/
	void SpendCoins(CCoinsViewCache &view, const CTransaction &tx, CTxUndo &txundo,
	int nHeight);

	/**
	* Apply the effects of this transaction on the UTXO set represented by view.
	*/
	void UpdateCoins(CCoinsViewCache &view, const CTransaction &tx, int nHeight);
	void UpdateCoins(CCoinsViewCache &view, const CTransaction &tx, CTxUndo &txundo,
	int nHeight);

	/**
	* Test whether the LockPoints height and time are still valid on the current
	* chain.
	*/
	bool TestLockPointValidity(const LockPoints *lp)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	/**
	* Check if transaction will be BIP 68 final in the next block to be created.
	*
	* Simulates calling SequenceLocks() with data from the tip of the current
	* active chain. Optionally stores in LockPoints the resulting height and time
	* calculated and the hash of the block needed for calculation or skips the
	* calculation and uses the LockPoints passed in for evaluation. The LockPoints
	* should not be considered valid if CheckSequenceLocks returns false.
	*
	* See consensus/consensus.h for flag definitions.
	*/
	bool CheckSequenceLocks(const CTxMemPool &pool, const CTransaction &tx,
	int flags, LockPoints *lp = nullptr,
	bool useExistingLockPoints = false)
	EXCLUSIVE_LOCKS_REQUIRED(::cs_main, pool.cs);

	/**
	* Closure representing one script verification.
	* Note that this stores references to the spending transaction.
	*
	* Note that if pLimitSigChecks is passed, then failure does not imply that
	* scripts have failed.
	*/
	class CScriptCheck {
	private:
	CTxOut m_tx_out;
	const CTransaction *ptxTo;
	unsigned int nIn;
	uint32_t nFlags;
	bool cacheStore;
	ScriptError error;
	ScriptExecutionMetrics metrics;
	PrecomputedTransactionData txdata;
	TxSigCheckLimiter *pTxLimitSigChecks;
	CheckInputsLimiter *pBlockLimitSigChecks;

	public:
	CScriptCheck()
	: ptxTo(nullptr), nIn(0), nFlags(0), cacheStore(false),
	error(ScriptError::UNKNOWN), txdata(), pTxLimitSigChecks(nullptr),
	pBlockLimitSigChecks(nullptr) {}

	CScriptCheck(const CTxOut &outIn, const CTransaction &txToIn,
	unsigned int nInIn, uint32_t nFlagsIn, bool cacheIn,
	const PrecomputedTransactionData &txdataIn,
	TxSigCheckLimiter *pTxLimitSigChecksIn = nullptr,
	CheckInputsLimiter *pBlockLimitSigChecksIn = nullptr)
	: m_tx_out(outIn), ptxTo(&txToIn), nIn(nInIn), nFlags(nFlagsIn),
	cacheStore(cacheIn), error(ScriptError::UNKNOWN), txdata(txdataIn),
	pTxLimitSigChecks(pTxLimitSigChecksIn),
	pBlockLimitSigChecks(pBlockLimitSigChecksIn) {}

	bool operator()();

	void swap(CScriptCheck &check) {
	std::swap(ptxTo, check.ptxTo);
	std::swap(m_tx_out, check.m_tx_out);
	std::swap(nIn, check.nIn);
	std::swap(nFlags, check.nFlags);
	std::swap(cacheStore, check.cacheStore);
	std::swap(error, check.error);
	std::swap(metrics, check.metrics);
	std::swap(txdata, check.txdata);
	std::swap(pTxLimitSigChecks, check.pTxLimitSigChecks);
	std::swap(pBlockLimitSigChecks, check.pBlockLimitSigChecks);
	}

	ScriptError GetScriptError() const { return error; }

	ScriptExecutionMetrics GetScriptExecutionMetrics() const { return metrics; }
	};

	bool UndoReadFromDisk(CBlockUndo &blockundo, const CBlockIndex *pindex);

	/** Functions for validating blocks and updating the block tree */

	/**
	* Context-independent validity checks.
	*
	* Returns true if the provided block is valid (has valid header,
	* transactions are valid, block is a valid size, etc.)
	*/
	bool CheckBlock(const CBlock &block, BlockValidationState &state,
	const Consensus::Params &params,
	BlockValidationOptions validationOptions);

	/**
	* This is a variant of ContextualCheckTransaction which computes the contextual
	* check for a transaction based on the chain tip.
	*
	* See consensus/consensus.h for flag definitions.
	*/
	bool ContextualCheckTransactionForCurrentBlock(const Consensus::Params &params,
	const CTransaction &tx,
	TxValidationState &state,
	int flags = -1)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	/**
	* Check a block is completely valid from start to finish (only works on top of
	* our current best block)
	*/
	bool TestBlockValidity(BlockValidationState &state, const CChainParams &params,
	const CBlock &block, CBlockIndex *pindexPrev,
	BlockValidationOptions validationOptions)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	/**
	* RAII wrapper for VerifyDB: Verify consistency of the block and coin
	* databases.
	*/
	class CVerifyDB {
	public:
	CVerifyDB();
	~CVerifyDB();
	bool VerifyDB(const Config &config, CCoinsView *coinsview, int nCheckLevel,
	int nCheckDepth);
	};

	CBlockIndex *LookupBlockIndex(const BlockHash &hash)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	/** Find the last common block between the parameter chain and a locator. */
	CBlockIndex *FindForkInGlobalIndex(const CChain &chain,
	const CBlockLocator &locator)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	/** @see CChainState::FlushStateToDisk */
	enum class FlushStateMode { NONE, IF_NEEDED, PERIODIC, ALWAYS };

	/** Global variable that points to the active CCoinsView (protected by cs_main)
	*/
	extern std::unique_ptr<CCoinsViewCache> pcoinsTip;

	/**
	* Maintains a tree of blocks (stored in `m_block_index`) which is consulted
	* to determine where the most-work tip is.
	*
	* This data is used mostly in `CChainState` - information about, e.g.,
	* candidate tips is not maintained here.
	*/
	class BlockManager {
	friend CChainState;

	private:
	/**
	* 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, int chain_tip_height);

	/**
	* Prune block and undo files (blk???.dat and undo???.dat) so that the disk
	* space used is less than a user-defined target. The user sets the target
	* (in MB) on the command line or in config file. This will be run on
	* startup and whenever new space is allocated in a block or undo file,
	* staying below the target. Changing back to unpruned requires a reindex
	* (which in this case means the blockchain must be re-downloaded.)
	*
	* Pruning functions are called from FlushStateToDisk when the global
	* fCheckForPruning flag has been set. Block and undo files are deleted in
	* lock-step (when blk00003.dat is deleted, so is rev00003.dat.) Pruning
	* cannot take place until the longest chain is at least a certain length
	* (100000 on mainnet, 1000 on testnet, 1000 on regtest). Pruning will never
	* delete a block within a defined distance (currently 288) from the active
	* chain's tip. The block index is updated by unsetting HAVE_DATA and
	* HAVE_UNDO for any blocks that were stored in the deleted files. A db flag
	* records the fact that at least some block files have been pruned.
	*
	* @param[out] setFilesToPrune The set of file indices that can be
	* unlinked will be returned
	*/
	void FindFilesToPrune(std::set<int> &setFilesToPrune,
	uint64_t nPruneAfterHeight, int chain_tip_height,
	bool is_ibd);

	public:
	BlockMap m_block_index GUARDED_BY(cs_main);

	/**
	* In order to efficiently track invalidity of headers, we keep the set of
	* blocks which we tried to connect and found to be invalid here (ie which
	* were set to BLOCK_FAILED_VALID since the last restart). We can then
	* walk this set and check if a new header is a descendant of something in
	* this set, preventing us from having to walk m_block_index when we try
	* to connect a bad block and fail.
	*
	* While this is more complicated than marking everything which descends
	* from an invalid block as invalid at the time we discover it to be
	* invalid, doing so would require walking all of m_block_index to find all
	* descendants. Since this case should be very rare, keeping track of all
	* BLOCK_FAILED_VALID blocks in a set should be just fine and work just as
	* well.
	*
	* Because we already walk m_block_index in height-order at startup, we go
	* ahead and mark descendants of invalid blocks as FAILED_CHILD at that
	* time, instead of putting things in this set.
	*/
	std::set<CBlockIndex *> m_failed_blocks;

	/**
	* 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 > m_blocks_unlinked;

	/**
	* Load the blocktree off disk and into memory. Populate certain metadata
	* per index entry (nStatus, nChainWork, nTimeMax, etc.) as well as
	* peripheral collections like setDirtyBlockIndex.
	*
	* @param[out] block_index_candidates Fill this set with any valid blocks
	* for which we've downloaded all transactions.
	*/
	bool LoadBlockIndex(const Consensus::Params &consensus_params,
	CBlockTreeDB &blocktree,
	std::set<CBlockIndex *, CBlockIndexWorkComparator>
	&block_index_candidates)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	/** Clear all data members. */
	void Unload() EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	CBlockIndex *AddToBlockIndex(const CBlockHeader &block)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);
	/** Create a new block index entry for a given block hash */
	CBlockIndex *InsertBlockIndex(const BlockHash &hash)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	//! Mark one block file as pruned (modify associated database entries)
	void PruneOneBlockFile(const int fileNumber)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	/**
	* If a block header hasn't already been seen, call CheckBlockHeader on it,
	* ensure that it doesn't descend from an invalid block, and then add it to
	* m_block_index.
	*/
	bool AcceptBlockHeader(const Config &config, const CBlockHeader &block,
	BlockValidationState &state, CBlockIndex **ppindex)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	~BlockManager() { Unload(); }
	};

	/**
	* A convenience class for constructing the CCoinsView* hierarchy used
	* to facilitate access to the UTXO set.
	*
	* This class consists of an arrangement of layered CCoinsView objects,
	* preferring to store and retrieve coins in memory via `m_cacheview` but
	* ultimately falling back on cache misses to the canonical store of UTXOs on
	* disk, `m_dbview`.
	*/
	class CoinsViews {
	public:
	//! The lowest level of the CoinsViews cache hierarchy sits in a leveldb
	//! database on disk. All unspent coins reside in this store.
	CCoinsViewDB m_dbview GUARDED_BY(cs_main);

	//! This view wraps access to the leveldb instance and handles read errors
	//! gracefully.
	CCoinsViewErrorCatcher m_catcherview GUARDED_BY(cs_main);

	//! This is the top layer of the cache hierarchy - it keeps as many coins in
	//! memory as can fit per the dbcache setting.
	std::unique_ptr<CCoinsViewCache> m_cacheview GUARDED_BY(cs_main);

	//! This constructor initializes CCoinsViewDB and CCoinsViewErrorCatcher
	//! instances, but it does not create a CCoinsViewCache instance by
	//! default. This is done separately because the presence of the cache has
	//! implications on whether or not we're allowed to flush the cache's state
	//! to disk, which should not be done until the health of the database is
	//! verified.
	//!
	//! All arguments forwarded onto CCoinsViewDB.
	CoinsViews(std::string ldb_name, size_t cache_size_bytes, bool in_memory,
	bool should_wipe);

	//! Initialize the CCoinsViewCache member.
	void InitCache() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
	};

	enum class CoinsCacheSizeState {
	//! The coins cache is in immediate need of a flush.
	CRITICAL = 2,
	//! The cache is at >= 90% capacity.
	LARGE = 1,
	OK = 0
	};

	/**
	* CChainState stores and provides an API to update our local knowledge of the
	* current best chain.
	*
	* Eventually, the API here is targeted at being exposed externally as a
	* consumable libconsensus library, so any functions added must only call
	* other class member functions, pure functions in other parts of the consensus
	* library, callbacks via the validation interface, or read/write-to-disk
	* functions (eventually this will also be via callbacks).
	*
	* Anything that is contingent on the current tip of the chain is stored here,
	* whereas block information and metadata independent of the current tip is
	* kept in `BlockMetadataManager`.
	*/
	class CChainState {
	private:
	/**
	* the ChainState CriticalSection
	* A lock that must be held when modifying this ChainState - held in
	* ActivateBestChain()
	*/
	RecursiveMutex m_cs_chainstate;

	/**
	* Every received block is assigned a unique and increasing identifier, so
	* we know which one to give priority in case of a fork.
	* Blocks loaded from disk are assigned id 0, so start the counter at 1.
	*/
	std::atomic<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;

	/**
	* Whether this chainstate is undergoing initial block download.
	*
	* Mutable because we need to be able to mark IsInitialBlockDownload()
	* const, which latches this for caching purposes.
	*/
	mutable std::atomic<bool> m_cached_finished_ibd{false};

	//! Reference to a BlockManager instance which itself is shared across all
	//! CChainState instances. Keeping a local reference allows us to test more
	//! easily as opposed to referencing a global.
	BlockManager &m_blockman;

	//! mempool that is kept in sync with the chain
	CTxMemPool &m_mempool;

	//! Manages the UTXO set, which is a reflection of the contents of
	//! `m_chain`.
	std::unique_ptr<CoinsViews> m_coins_views;

	/**
	* The best finalized block.
	* This block cannot be reorged in any way except by explicit user action.
	*/
	const CBlockIndex *m_finalizedBlockIndex GUARDED_BY(cs_main) = nullptr;

	public:
	explicit CChainState(CTxMemPool &mempool, BlockManager &blockman,
	BlockHash from_snapshot_blockhash = BlockHash());

	/**
	* Initialize the CoinsViews UTXO set database management data structures.
	* The in-memory cache is initialized separately.
	*
	* All parameters forwarded to CoinsViews.
	*/
	void InitCoinsDB(size_t cache_size_bytes, bool in_memory, bool should_wipe,
	std::string leveldb_name = "chainstate");

	//! Initialize the in-memory coins cache (to be done after the health of the
	//! on-disk database is verified).
	void InitCoinsCache(size_t cache_size_bytes)
	EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

	//! @returns whether or not the CoinsViews object has been fully initialized
	//! and we can
	//! safely flush this object to disk.
	bool CanFlushToDisk() EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
	return m_coins_views && m_coins_views->m_cacheview;
	}

	//! The current chain of blockheaders we consult and build on.
	//! @see CChain, CBlockIndex.
	CChain m_chain;

	/**
	* The blockhash which is the base of the snapshot this chainstate was
	* created from.
	*
	* IsNull() if this chainstate was not created from a snapshot.
	*/
	const BlockHash m_from_snapshot_blockhash{};

	/**
	* 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;

	//! @returns A reference to the in-memory cache of the UTXO set.
	CCoinsViewCache &CoinsTip() EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
	assert(m_coins_views->m_cacheview);
	return *m_coins_views->m_cacheview.get();
	}

	//! @returns A reference to the on-disk UTXO set database.
	CCoinsViewDB &CoinsDB() { return m_coins_views->m_dbview; }

	//! @returns A reference to a wrapped view of the in-memory UTXO set that
	//! handles disk read errors gracefully.
	CCoinsViewErrorCatcher &CoinsErrorCatcher()
	EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
	return m_coins_views->m_catcherview;
	}

	//! Destructs all objects related to accessing the UTXO set.
	void ResetCoinsViews() { m_coins_views.reset(); }

	//! The cache size of the on-disk coins view.
	size_t m_coinsdb_cache_size_bytes{0};

	//! The cache size of the in-memory coins view.
	size_t m_coinstip_cache_size_bytes{0};

	//! Resize the CoinsViews caches dynamically and flush state to disk.
	//! @returns true unless an error occurred during the flush.
	bool ResizeCoinsCaches(size_t coinstip_size, size_t coinsdb_size)
	EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

	/**
	* 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.
	*
	* If FlushStateMode::NONE is used, then FlushStateToDisk(...) won't do
	* anything besides checking if we need to prune.
	*
	* @returns true unless a system error occurred
	*/
	bool FlushStateToDisk(const CChainParams &chainparams,
	BlockValidationState &state, FlushStateMode mode,
	int nManualPruneHeight = 0);

	//! Unconditionally flush all changes to disk.
	void ForceFlushStateToDisk();

	//! Prune blockfiles from the disk if necessary and then flush chainstate
	//! changes if we pruned.
	void PruneAndFlush();

	/**
	* 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).
	*
	* ActivateBestChain is split into steps (see ActivateBestChainStep) so that
	* we avoid holding cs_main for an extended period of time; the length of
	* this call may be quite long during reindexing or a substantial reorg.
	*
	* May not be called with cs_main held. May not be called in a
	* validationinterface callback.
	*
	* @returns true unless a system error occurred
	*/
	bool ActivateBestChain(
	const Config &config, BlockValidationState &state,
	std::shared_ptr<const CBlock> pblock = std::shared_ptr<const CBlock>())
	LOCKS_EXCLUDED(cs_main);

	bool AcceptBlock(const Config &config,
	const std::shared_ptr<const CBlock> &pblock,
	BlockValidationState &state, bool fRequested,
	const FlatFilePos dbp, bool fNewBlock)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	// Block (dis)connection on a given view:
	DisconnectResult DisconnectBlock(const CBlock &block,
	const CBlockIndex *pindex,
	CCoinsViewCache &view);
	bool ConnectBlock(const CBlock &block, BlockValidationState &state,
	CBlockIndex *pindex, CCoinsViewCache &view,
	const CChainParams &params,
	BlockValidationOptions options, bool fJustCheck = false)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	// Block disconnection on our pcoinsTip:
	bool DisconnectTip(const CChainParams &params, BlockValidationState &state,
	DisconnectedBlockTransactions *disconnectpool)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_mempool.cs);

	// Manual block validity manipulation:
	bool PreciousBlock(const Config &config, BlockValidationState &state,
	CBlockIndex *pindex) LOCKS_EXCLUDED(cs_main);
	/** Mark a block as invalid. */
	bool InvalidateBlock(const Config &config, BlockValidationState &state,
	CBlockIndex *pindex) LOCKS_EXCLUDED(cs_main)
	EXCLUSIVE_LOCKS_REQUIRED(!m_cs_chainstate);
	/** Park a block. */
	bool ParkBlock(const Config &config, BlockValidationState &state,
	CBlockIndex *pindex) LOCKS_EXCLUDED(cs_main)
	EXCLUSIVE_LOCKS_REQUIRED(!m_cs_chainstate);

	/**
	* Finalize a block.
	* A finalized block can not be reorged in any way.
	*/
	bool FinalizeBlock(const Config &config, BlockValidationState &state,
	CBlockIndex *pindex) LOCKS_EXCLUDED(cs_main)
	EXCLUSIVE_LOCKS_REQUIRED(!m_cs_chainstate);
	/** Return the currently finalized block index. */
	const CBlockIndex *GetFinalizedBlock() const
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);
	/**
	* Checks if a block is finalized.
	*/
	bool IsBlockFinalized(const CBlockIndex *pindex) const
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	void ResetBlockFailureFlags(CBlockIndex *pindex)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);
	template <typename F>
	bool UpdateFlagsForBlock(CBlockIndex pindexBase, CBlockIndex pindex, F f)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);
	template <typename F, typename C, typename AC>
	void UpdateFlags(CBlockIndex pindex, CBlockIndex &pindexReset, F f,
	C fChild, AC fAncestorWasChanged)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);
	/** Remove parked status from a block and its descendants. */
	void UnparkBlockImpl(CBlockIndex *pindex, bool fClearChildren)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	/** Replay blocks that aren't fully applied to the database. */
	bool ReplayBlocks(const Consensus::Params &params);
	bool LoadGenesisBlock(const CChainParams &chainparams);

	void PruneBlockIndexCandidates();

	void UnloadBlockIndex() EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	/**
	* Check whether we are doing an initial block download (synchronizing from
	* disk or network)
	*/
	bool IsInitialBlockDownload() const;

	/**
	* Make various assertions about the state of the block index.
	*
	* By default this only executes fully when using the Regtest chain; see:
	* fCheckBlockIndex.
	*/
	void CheckBlockIndex(const Consensus::Params &consensusParams);

	/** Load the persisted mempool from disk */
	void LoadMempool(const Config &config, const ArgsManager &args);

	/** Update the chain tip based on database information, i.e. CoinsTip()'s
	* best block. */
	bool LoadChainTip(const CChainParams &chainparams)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	//! Dictates whether we need to flush the cache to disk or not.
	//!
	//! @return the state of the size of the coins cache.
	CoinsCacheSizeState GetCoinsCacheSizeState(const CTxMemPool *tx_pool)
	EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

	CoinsCacheSizeState GetCoinsCacheSizeState(
	const CTxMemPool *tx_pool, size_t max_coins_cache_size_bytes,
	size_t max_mempool_size_bytes) EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

	std::string ToString() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

	private:
	bool ActivateBestChainStep(const Config &config,
	BlockValidationState &state,
	CBlockIndex *pindexMostWork,
	const std::shared_ptr<const CBlock> &pblock,
	bool &fInvalidFound, ConnectTrace &connectTrace)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_mempool.cs);
	bool ConnectTip(const Config &config, BlockValidationState &state,
	CBlockIndex *pindexNew,
	const std::shared_ptr<const CBlock> &pblock,
	ConnectTrace &connectTrace,
	DisconnectedBlockTransactions &disconnectpool)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_mempool.cs);
	void InvalidBlockFound(CBlockIndex *pindex,
	const BlockValidationState &state)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);
	void InvalidChainFound(CBlockIndex *pindexNew)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);
	CBlockIndex *FindMostWorkChain() EXCLUSIVE_LOCKS_REQUIRED(cs_main);
	bool MarkBlockAsFinal(BlockValidationState &state,
	const CBlockIndex *pindex)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);
	void ReceivedBlockTransactions(const CBlock &block, CBlockIndex *pindexNew,
	const FlatFilePos &pos)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	bool RollforwardBlock(const CBlockIndex *pindex, CCoinsViewCache &inputs,
	const Consensus::Params &params)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);
	bool UnwindBlock(const Config &config, BlockValidationState &state,
	CBlockIndex *pindex, bool invalidate)
	EXCLUSIVE_LOCKS_REQUIRED(m_cs_chainstate);

	friend ChainstateManager;
	};

	/**
	* Mark a block as precious and reorganize.
	*
	* May not be called in a validationinterface callback.
	*/
	bool PreciousBlock(const Config &config, BlockValidationState &state,
	CBlockIndex *pindex) LOCKS_EXCLUDED(cs_main);

	/** Remove invalidity status from a block and its descendants. */
	void ResetBlockFailureFlags(CBlockIndex *pindex)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	/** Remove parked status from a block and its descendants. */
	void UnparkBlockAndChildren(CBlockIndex *pindex)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	/** Remove parked status from a block. */
	void UnparkBlock(CBlockIndex *pindex) EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	/**
	* Provides an interface for creating and interacting with one or two
	* chainstates: an IBD chainstate generated by downloading blocks, and
	* an optional snapshot chainstate loaded from a UTXO snapshot. Managed
	* chainstates can be maintained at different heights simultaneously.
	*
	* This class provides abstractions that allow the retrieval of the current
	* most-work chainstate ("Active") as well as chainstates which may be in
	* background use to validate UTXO snapshots.
	*
	* Definitions:
	*
	* IBD chainstate: a chainstate whose current state has been "fully"
	* validated by the initial block download process.
	*
	* Snapshot chainstate: a chainstate populated by loading in an
	* assumeutxo UTXO snapshot.
	*
	* Active chainstate: the chainstate containing the current most-work
	* chain. Consulted by most parts of the system (net_processing,
	* wallet) as a reflection of the current chain and UTXO set.
	* This may either be an IBD chainstate or a snapshot chainstate.
	*
	* Background IBD chainstate: an IBD chainstate for which the
	* IBD process is happening in the background while use of the
	* active (snapshot) chainstate allows the rest of the system to function.
	*
	* Validated chainstate: the most-work chainstate which has been validated
	* locally via initial block download. This will be the snapshot chainstate
	* if a snapshot was loaded and all blocks up to the snapshot starting point
	* have been downloaded and validated (via background validation), otherwise
	* it will be the IBD chainstate.
	*/
	class ChainstateManager {
	private:
	//! The chainstate used under normal operation (i.e. "regular" IBD) or, if
	//! a snapshot is in use, for background validation.
	//!
	//! Its contents (including on-disk data) will be deleted upon shutdown
	//! after background validation of the snapshot has completed. We do not
	//! free the chainstate contents immediately after it finishes validation
	//! to cautiously avoid a case where some other part of the system is still
	//! using this pointer (e.g. net_processing).
	//!
	//! Once this pointer is set to a corresponding chainstate, it will not
	//! be reset until init.cpp:Shutdown(). This means it is safe to acquire
	//! the contents of this pointer with ::cs_main held, release the lock,
	//! and then use the reference without concern of it being deconstructed.
	//!
	//! This is especially important when, e.g., calling ActivateBestChain()
	//! on all chainstates because we are not able to hold ::cs_main going into
	//! that call.
	std::unique_ptr<CChainState> m_ibd_chainstate;

	//! A chainstate initialized on the basis of a UTXO snapshot. If this is
	//! non-null, it is always our active chainstate.
	//!
	//! Once this pointer is set to a corresponding chainstate, it will not
	//! be reset until init.cpp:Shutdown(). This means it is safe to acquire
	//! the contents of this pointer with ::cs_main held, release the lock,
	//! and then use the reference without concern of it being deconstructed.
	//!
	//! This is especially important when, e.g., calling ActivateBestChain()
	//! on all chainstates because we are not able to hold ::cs_main going into
	//! that call.
	std::unique_ptr<CChainState> m_snapshot_chainstate;

	//! Points to either the ibd or snapshot chainstate; indicates our
	//! most-work chain.
	//!
	//! Once this pointer is set to a corresponding chainstate, it will not
	//! be reset until init.cpp:Shutdown(). This means it is safe to acquire
	//! the contents of this pointer with ::cs_main held, release the lock,
	//! and then use the reference without concern of it being deconstructed.
	//!
	//! This is especially important when, e.g., calling ActivateBestChain()
	//! on all chainstates because we are not able to hold ::cs_main going into
	//! that call.
	CChainState *m_active_chainstate{nullptr};

	//! If true, the assumed-valid chainstate has been fully validated
	//! by the background validation chainstate.
	bool m_snapshot_validated{false};

	// For access to m_active_chainstate.
	friend CChainState &ChainstateActive();
	friend CChain &ChainActive();

	public:
	//! A single BlockManager instance is shared across each constructed
	//! chainstate to avoid duplicating block metadata.
	BlockManager m_blockman GUARDED_BY(::cs_main);

	//! The total number of bytes available for us to use across all in-memory
	//! coins caches. This will be split somehow across chainstates.
	int64_t m_total_coinstip_cache{0};
	//
	//! The total number of bytes available for us to use across all leveldb
	//! coins databases. This will be split somehow across chainstates.
	int64_t m_total_coinsdb_cache{0};

	//! Instantiate a new chainstate and assign it based upon whether it is
	//! from a snapshot.
	//!
	//! @param[in] mempool The mempool to pass to the chainstate
	// constructor
	//! @param[in] snapshot_blockhash If given, signify that this chainstate
	//! is based on a snapshot.
	CChainState &
	InitializeChainstate(CTxMemPool &mempool,
	const BlockHash &snapshot_blockhash = BlockHash())
	EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

	//! Get all chainstates currently being used.
	std::vector<CChainState *> GetAll();

	//! The most-work chain.
	CChainState &ActiveChainstate() const;
	CChain &ActiveChain() const { return ActiveChainstate().m_chain; }
	int ActiveHeight() const { return ActiveChain().Height(); }
	CBlockIndex *ActiveTip() const { return ActiveChain().Tip(); }

	BlockMap &BlockIndex() EXCLUSIVE_LOCKS_REQUIRED(::cs_main) {
	return m_blockman.m_block_index;
	}

	bool IsSnapshotActive() const;

	std::optional<BlockHash> SnapshotBlockhash() const;

	//! Is there a snapshot in use and has it been fully validated?
	bool IsSnapshotValidated() const { return m_snapshot_validated; }

	//! @returns true if this chainstate is being used to validate an active
	//! snapshot in the background.
	bool IsBackgroundIBD(CChainState *chainstate) const;

	//! Return the most-work chainstate that has been fully validated.
	//!
	//! During background validation of a snapshot, this is the IBD chain. After
	//! background validation has completed, this is the snapshot chain.
	CChainState &ValidatedChainstate() const;

	CChain &ValidatedChain() const { return ValidatedChainstate().m_chain; }
	CBlockIndex *ValidatedTip() const { return ValidatedChain().Tip(); }

	/**
	* Process an incoming block. This only returns after the best known valid
	* block is made active. Note that it does not, however, guarantee that the
	* specific block passed to it has been checked for validity!
	*
	* If you want to possibly get feedback on whether pblock is valid, you
	* must install a CValidationInterface (see validationinterface.h) - this
	* will have its BlockChecked method called whenever any block completes
	* validation.
	*
	* Note that we guarantee that either the proof-of-work is valid on pblock,
	* or (and possibly also) BlockChecked will have been called.
	*
	* May not be called in a validationinterface callback.
	*
	* @param[in] config The global config.
	* @param[in] pblock The block we want to process.
	* @param[in] fForceProcessing Process this block even if unrequested;
	* used for non-network block sources.
	* @param[out] fNewBlock A boolean which is set to indicate if the block
	* was first received via this call.
	* @returns If the block was processed, independently of block validity
	*/
	bool ProcessNewBlock(const Config &config,
	const std::shared_ptr<const CBlock> pblock,
	bool fForceProcessing, bool *fNewBlock)
	LOCKS_EXCLUDED(cs_main);

	/**
	* Process incoming block headers.
	*
	* May not be called in a validationinterface callback.
	*
	* @param[in] config The config.
	* @param[in] block The block headers themselves.
	* @param[out] state This may be set to an Error state if any error
	* occurred processing them.
	* @param[out] ppindex If set, the pointer will be set to point to the
	* last new block index object for the given
	* headers.
	* @return True if block headers were accepted as valid.
	*/
	bool ProcessNewBlockHeaders(const Config &config,
	const std::vector<CBlockHeader> &block,
	BlockValidationState &state,
	const CBlockIndex **ppindex = nullptr)
	LOCKS_EXCLUDED(cs_main);

	//! Load the block tree and coins database from disk, initializing state if
	//! we're running with -reindex
	bool LoadBlockIndex(const Consensus::Params &params)
	EXCLUSIVE_LOCKS_REQUIRED(cs_main);

	//! Unload block index and chain data before shutdown.
	void Unload() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);

	//! Clear (deconstruct) chainstate data.
	void Reset();

	//! Check to see if caches are out of balance and if so, call
	//! ResizeCoinsCaches() as needed.
	void MaybeRebalanceCaches() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
	};

	/**
	* DEPRECATED! Please use node.chainman instead. May only be used in
	* validation.cpp internally
	*/
	extern ChainstateManager g_chainman GUARDED_BY(::cs_main);

	/** Please prefer the identical ChainstateManager::ActiveChainstate */
	CChainState &ChainstateActive();

	/** Please prefer the identical ChainstateManager::ActiveChain */
	CChain &ChainActive();

	/**
	* Global variable that points to the active block tree (protected by cs_main)
	*/
	extern std::unique_ptr<CBlockTreeDB> pblocktree;

	/**
	* Return the spend height, which is one more than the inputs.GetBestBlock().
	* While checking, GetBestBlock() refers to the parent block. (protected by
	* cs_main)
	* This is also true for mempool checks.
	*/
	int GetSpendHeight(const CCoinsViewCache &inputs);

	/**
	* Determine what nVersion a new block should use.
	*/
	int32_t ComputeBlockVersion(const CBlockIndex *pindexPrev,
	const Consensus::Params &params);

	/** Get block file info entry for one block file */
	CBlockFileInfo *GetBlockFileInfo(size_t n);

	/** Dump the mempool to disk. */
	bool DumpMempool(const CTxMemPool &pool);

	/** Load the mempool from disk. */
	bool LoadMempool(const Config &config, CTxMemPool &pool);

	//! Check whether the block associated with this index entry is pruned or not.
	bool IsBlockPruned(const CBlockIndex *pblockindex);

	#endif // BITCOIN_VALIDATION_H

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