diff --git a/src/index/txindex.h b/src/index/txindex.h --- a/src/index/txindex.h +++ b/src/index/txindex.h @@ -15,38 +15,30 @@ class CBlockIndex; /** - * TxIndex is used to look up transactions included in the blockchain by hash. - * The index is written to a LevelDB database and records the filesystem - * location of each transaction by transaction hash. + * Base class for indices of blockchain data. This implements + * CValidationInterface and ensures blocks are indexed sequentially according + * to their position in the active chain. */ -class TxIndex final : public CValidationInterface { +class BaseIndex : public CValidationInterface { private: - const std::unique_ptr m_db; - /// Whether the index is in sync with the main chain. The flag is flipped /// from false to true once, after which point this starts processing /// ValidationInterface notifications to stay in sync. - std::atomic m_synced; + std::atomic m_synced{false}; - /// The last block in the chain that the TxIndex is in sync with. - std::atomic m_best_block_index; + /// The last block in the chain that the index is in sync with. + std::atomic m_best_block_index{nullptr}; std::thread m_thread_sync; CThreadInterrupt m_interrupt; - /// Initialize internal state from the database and block index. - bool Init(); - - /// Sync the tx index with the block index starting from the current best + /// Sync the index with the block index starting from the current best /// block. Intended to be run in its own thread, m_thread_sync, and can be - /// interrupted with m_interrupt. Once the txindex gets in sync, the - /// m_synced flag is set and the BlockConnected ValidationInterface callback - /// takes over and the sync thread exits. + /// interrupted with m_interrupt. Once the index gets in sync, the m_synced + /// flag is set and the BlockConnected ValidationInterface callback takes + /// over and the sync thread exits. void ThreadSync(); - /// Write update index entries for a newly connected block. - bool WriteBlock(const CBlock &block, const CBlockIndex *pindex); - /// Write the current chain block locator to the DB. bool WriteBestBlock(const CBlockIndex *block_index); @@ -58,20 +50,58 @@ void ChainStateFlushed(const CBlockLocator &locator) override; -public: - /// Constructs the TxIndex, which becomes available to be queried. - explicit TxIndex(std::unique_ptr db); + /// Initialize internal state from the database and block index. + virtual bool Init(); + /// Write update index entries for a newly connected block. + virtual bool WriteBlock(const CBlock &block, const CBlockIndex *pindex) { + return true; + } + + virtual BaseIndexDB &GetDB() const = 0; + +public: /// Destructor interrupts sync thread if running and blocks until it exits. - ~TxIndex(); + virtual ~BaseIndex(); - /// Blocks the current thread until the transaction index is caught up to - /// the current state of the block chain. This only blocks if the index has - /// gotten in sync once and only needs to process blocks in the - /// ValidationInterface queue. If the index is catching up from far behind, - /// this method does not block and immediately returns false. + /// Blocks the current thread until the index is caught up to the current + /// state of the block chain. This only blocks if the index has gotten in + /// sync once and only needs to process blocks in the ValidationInterface + /// queue. If the index is catching up from far behind, this method does + /// not block and immediately returns false. bool BlockUntilSyncedToCurrentChain(); + void Interrupt(); + + /// Start initializes the sync state and registers the instance as a + /// ValidationInterface so that it stays in sync with blockchain updates. + void Start(); + + /// Stops the instance from staying in sync with blockchain updates. + void Stop(); +}; + +/** + * TxIndex is used to look up transactions included in the blockchain by hash. + * The index is written to a LevelDB database and records the filesystem + * location of each transaction by transaction hash. + */ +class TxIndex final : public BaseIndex { +private: + const std::unique_ptr m_db; + +protected: + /// Override base class init to migrate from old database. + bool Init() override; + + bool WriteBlock(const CBlock &block, const CBlockIndex *pindex) override; + + BaseIndexDB &GetDB() const override; + +public: + /// Constructs the index, which becomes available to be queried. + explicit TxIndex(std::unique_ptr db); + /// Look up a transaction by hash. /// /// @param[in] tx_hash The hash of the transaction to be returned. @@ -81,15 +111,6 @@ /// @return true if transaction is found, false otherwise bool FindTx(const uint256 &tx_hash, uint256 &block_hash, CTransactionRef &tx) const; - - void Interrupt(); - - /// Start initializes the sync state and registers the instance as a - /// ValidationInterface so that it stays in sync with blockchain updates. - void Start(); - - /// Stops the instance from staying in sync with blockchain updates. - void Stop(); }; /// The global transaction index, used in GetTransaction. May be null. diff --git a/src/index/txindex.cpp b/src/index/txindex.cpp --- a/src/index/txindex.cpp +++ b/src/index/txindex.cpp @@ -27,10 +27,9 @@ StartShutdown(); } -TxIndex::TxIndex(std::unique_ptr db) - : m_db(std::move(db)), m_synced(false), m_best_block_index(nullptr) {} +TxIndex::TxIndex(std::unique_ptr db) : m_db(std::move(db)) {} -TxIndex::~TxIndex() { +BaseIndex::~BaseIndex() { Interrupt(); Stop(); } @@ -45,11 +44,16 @@ return false; } + return BaseIndex::Init(); +} + +bool BaseIndex::Init() { CBlockLocator locator; - if (!m_db->ReadBestBlock(locator)) { + if (!GetDB().ReadBestBlock(locator)) { locator.SetNull(); } + LOCK(cs_main); m_best_block_index = FindForkInGlobalIndex(chainActive, locator); m_synced = m_best_block_index.load() == chainActive.Tip(); return true; @@ -70,7 +74,7 @@ return chainActive.Next(chainActive.FindFork(pindex_prev)); } -void TxIndex::ThreadSync() { +void BaseIndex::ThreadSync() { const CBlockIndex *pindex = m_best_block_index.load(); if (!m_synced) { auto &config = GetConfig(); @@ -141,15 +145,19 @@ return m_db->WriteTxs(vPos); } -bool TxIndex::WriteBestBlock(const CBlockIndex *block_index) { +BaseIndexDB &TxIndex::GetDB() const { + return *m_db; +} + +bool BaseIndex::WriteBestBlock(const CBlockIndex *block_index) { LOCK(cs_main); - if (!m_db->WriteBestBlock(chainActive.GetLocator(block_index))) { + if (!GetDB().WriteBestBlock(chainActive.GetLocator(block_index))) { return error("%s: Failed to write locator to disk", __func__); } return true; } -void TxIndex::BlockConnected( +void BaseIndex::BlockConnected( const std::shared_ptr &block, const CBlockIndex *pindex, const std::vector &txn_conflicted) { if (!m_synced) { @@ -191,7 +199,7 @@ } } -void TxIndex::ChainStateFlushed(const CBlockLocator &locator) { +void BaseIndex::ChainStateFlushed(const CBlockLocator &locator) { if (!m_synced) { return; } @@ -225,12 +233,12 @@ return; } - if (!m_db->WriteBestBlock(locator)) { + if (!GetDB().WriteBestBlock(locator)) { error("%s: Failed to write locator to disk", __func__); } } -bool TxIndex::BlockUntilSyncedToCurrentChain() { +bool BaseIndex::BlockUntilSyncedToCurrentChain() { AssertLockNotHeld(cs_main); if (!m_synced) { @@ -279,11 +287,11 @@ return true; } -void TxIndex::Interrupt() { +void BaseIndex::Interrupt() { m_interrupt(); } -void TxIndex::Start() { +void BaseIndex::Start() { // Need to register this ValidationInterface before running Init(), so that // callbacks are not missed if Init sets m_synced to true. RegisterValidationInterface(this); @@ -293,10 +301,10 @@ } m_thread_sync = std::thread(&TraceThread>, "txindex", - std::bind(&TxIndex::ThreadSync, this)); + std::bind(&BaseIndex::ThreadSync, this)); } -void TxIndex::Stop() { +void BaseIndex::Stop() { UnregisterValidationInterface(this); if (m_thread_sync.joinable()) {