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src/index/txindex.h
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#include <threadinterrupt.h> | #include <threadinterrupt.h> | ||||
#include <txdb.h> | #include <txdb.h> | ||||
#include <uint256.h> | #include <uint256.h> | ||||
#include <validationinterface.h> | #include <validationinterface.h> | ||||
class CBlockIndex; | class CBlockIndex; | ||||
/** | /** | ||||
* TxIndex is used to look up transactions included in the blockchain by hash. | * Base class for indices of blockchain data. This implements | ||||
* The index is written to a LevelDB database and records the filesystem | * CValidationInterface and ensures blocks are indexed sequentially according | ||||
* location of each transaction by transaction hash. | * to their position in the active chain. | ||||
*/ | */ | ||||
class TxIndex final : public CValidationInterface { | class BaseIndex : public CValidationInterface { | ||||
private: | private: | ||||
const std::unique_ptr<TxIndexDB> m_db; | |||||
/// Whether the index is in sync with the main chain. The flag is flipped | /// 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 | /// from false to true once, after which point this starts processing | ||||
/// ValidationInterface notifications to stay in sync. | /// ValidationInterface notifications to stay in sync. | ||||
std::atomic<bool> m_synced; | std::atomic<bool> m_synced{false}; | ||||
/// The last block in the chain that the TxIndex is in sync with. | /// The last block in the chain that the index is in sync with. | ||||
std::atomic<const CBlockIndex *> m_best_block_index; | std::atomic<const CBlockIndex *> m_best_block_index{nullptr}; | ||||
std::thread m_thread_sync; | std::thread m_thread_sync; | ||||
CThreadInterrupt m_interrupt; | CThreadInterrupt m_interrupt; | ||||
/// Initialize internal state from the database and block index. | /// Sync the index with the block index starting from the current best | ||||
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 | /// 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 | /// interrupted with m_interrupt. Once the index gets in sync, the m_synced | ||||
/// m_synced flag is set and the BlockConnected ValidationInterface callback | /// flag is set and the BlockConnected ValidationInterface callback takes | ||||
/// takes over and the sync thread exits. | /// over and the sync thread exits. | ||||
void ThreadSync(); | 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. | /// Write the current chain block locator to the DB. | ||||
bool WriteBestBlock(const CBlockIndex *block_index); | bool WriteBestBlock(const CBlockIndex *block_index); | ||||
protected: | protected: | ||||
void | void | ||||
BlockConnected(const std::shared_ptr<const CBlock> &block, | BlockConnected(const std::shared_ptr<const CBlock> &block, | ||||
const CBlockIndex *pindex, | const CBlockIndex *pindex, | ||||
const std::vector<CTransactionRef> &txn_conflicted) override; | const std::vector<CTransactionRef> &txn_conflicted) override; | ||||
void ChainStateFlushed(const CBlockLocator &locator) override; | void ChainStateFlushed(const CBlockLocator &locator) override; | ||||
public: | /// Initialize internal state from the database and block index. | ||||
/// Constructs the TxIndex, which becomes available to be queried. | virtual bool Init(); | ||||
explicit TxIndex(std::unique_ptr<TxIndexDB> db); | |||||
/// 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. | /// 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 | /// Blocks the current thread until the index is caught up to the current | ||||
/// the current state of the block chain. This only blocks if the index has | /// state of the block chain. This only blocks if the index has gotten in | ||||
/// gotten in sync once and only needs to process blocks in the | /// sync once and only needs to process blocks in the ValidationInterface | ||||
/// ValidationInterface queue. If the index is catching up from far behind, | /// queue. If the index is catching up from far behind, this method does | ||||
/// this method does not block and immediately returns false. | /// not block and immediately returns false. | ||||
bool BlockUntilSyncedToCurrentChain(); | 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<TxIndexDB> 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<TxIndexDB> db); | |||||
/// Look up a transaction by hash. | /// Look up a transaction by hash. | ||||
/// | /// | ||||
/// @param[in] tx_hash The hash of the transaction to be returned. | /// @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 | /// @param[out] block_hash The hash of the block the transaction is found | ||||
/// in. | /// in. | ||||
/// @param[out] tx The transaction itself. | /// @param[out] tx The transaction itself. | ||||
/// @return true if transaction is found, false otherwise | /// @return true if transaction is found, false otherwise | ||||
bool FindTx(const uint256 &tx_hash, uint256 &block_hash, | bool FindTx(const uint256 &tx_hash, uint256 &block_hash, | ||||
CTransactionRef &tx) const; | 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. | /// The global transaction index, used in GetTransaction. May be null. | ||||
extern std::unique_ptr<TxIndex> g_txindex; | extern std::unique_ptr<TxIndex> g_txindex; | ||||
#endif // BITCOIN_INDEX_TXINDEX_H | #endif // BITCOIN_INDEX_TXINDEX_H |