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Diffstat (limited to 'src/index/txindex.h')
-rw-r--r-- | src/index/txindex.h | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/src/index/txindex.h b/src/index/txindex.h new file mode 100644 index 0000000000..4937bd64e9 --- /dev/null +++ b/src/index/txindex.h @@ -0,0 +1,94 @@ +// Copyright (c) 2017-2018 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_INDEX_TXINDEX_H +#define BITCOIN_INDEX_TXINDEX_H + +#include <primitives/block.h> +#include <primitives/transaction.h> +#include <threadinterrupt.h> +#include <txdb.h> +#include <uint256.h> +#include <validationinterface.h> + +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. + */ +class TxIndex final : public CValidationInterface +{ +private: + const std::unique_ptr<TxIndexDB> 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<bool> m_synced; + + /// The last block in the chain that the TxIndex is in sync with. + std::atomic<const CBlockIndex*> m_best_block_index; + + 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 + /// 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. + 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); + +protected: + void BlockConnected(const std::shared_ptr<const CBlock>& block, const CBlockIndex* pindex, + const std::vector<CTransactionRef>& txn_conflicted) override; + + void ChainStateFlushed(const CBlockLocator& locator) override; + +public: + /// Constructs the TxIndex, which becomes available to be queried. + explicit TxIndex(std::unique_ptr<TxIndexDB> db); + + /// Destructor interrupts sync thread if running and blocks until it exits. + ~TxIndex(); + + /// 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. + bool BlockUntilSyncedToCurrentChain(); + + /// Look up a transaction by hash. + /// + /// @param[in] tx_hash The hash of the transaction to be returned. + /// @param[out] block_hash The hash of the block the transaction is found in. + /// @param[out] tx The transaction itself. + /// @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. +extern std::unique_ptr<TxIndex> g_txindex; + +#endif // BITCOIN_INDEX_TXINDEX_H |