Bitcoin Core  0.20.99
P2P Digital Currency
Classes | Public Member Functions | Protected Member Functions | Private Member Functions | Private Attributes | List of all members
BaseIndex Class Referenceabstract

Base class for indices of blockchain data. More...

#include <base.h>

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Classes

class  DB
 The database stores a block locator of the chain the database is synced to so that the index can efficiently determine the point it last stopped at. More...
 

Public Member Functions

virtual ~BaseIndex ()
 Destructor interrupts sync thread if running and blocks until it exits. More...
 
bool BlockUntilSyncedToCurrentChain () const
 Blocks the current thread until the index is caught up to the current state of the block chain. More...
 
void Interrupt ()
 
void Start ()
 Start initializes the sync state and registers the instance as a ValidationInterface so that it stays in sync with blockchain updates. More...
 
void Stop ()
 Stops the instance from staying in sync with blockchain updates. More...
 
IndexSummary GetSummary () const
 Get a summary of the index and its state. More...
 

Protected Member Functions

void BlockConnected (const std::shared_ptr< const CBlock > &block, const CBlockIndex *pindex) override
 Notifies listeners of a block being connected. More...
 
void ChainStateFlushed (const CBlockLocator &locator) override
 Notifies listeners of the new active block chain on-disk. More...
 
virtual bool Init ()
 Initialize internal state from the database and block index. More...
 
virtual bool WriteBlock (const CBlock &block, const CBlockIndex *pindex)
 Write update index entries for a newly connected block. More...
 
virtual bool CommitInternal (CDBBatch &batch)
 Virtual method called internally by Commit that can be overridden to atomically commit more index state. More...
 
virtual bool Rewind (const CBlockIndex *current_tip, const CBlockIndex *new_tip)
 Rewind index to an earlier chain tip during a chain reorg. More...
 
virtual DBGetDB () const =0
 
virtual const char * GetName () const =0
 Get the name of the index for display in logs. More...
 
- Protected Member Functions inherited from CValidationInterface
 ~CValidationInterface ()=default
 Protected destructor so that instances can only be deleted by derived classes. More...
 
virtual void UpdatedBlockTip (const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload)
 Notifies listeners when the block chain tip advances. More...
 
virtual void TransactionAddedToMempool (const CTransactionRef &tx, uint64_t mempool_sequence)
 Notifies listeners of a transaction having been added to mempool. More...
 
virtual void TransactionRemovedFromMempool (const CTransactionRef &tx, MemPoolRemovalReason reason, uint64_t mempool_sequence)
 Notifies listeners of a transaction leaving mempool. More...
 
virtual void BlockDisconnected (const std::shared_ptr< const CBlock > &block, const CBlockIndex *pindex)
 Notifies listeners of a block being disconnected. More...
 
virtual void BlockChecked (const CBlock &, const BlockValidationState &)
 Notifies listeners of a block validation result. More...
 
virtual void NewPoWValidBlock (const CBlockIndex *pindex, const std::shared_ptr< const CBlock > &block)
 Notifies listeners that a block which builds directly on our current tip has been received and connected to the headers tree, though not validated yet. More...
 

Private Member Functions

void ThreadSync ()
 Sync the index with the block index starting from the current best block. More...
 
bool Commit ()
 Write the current index state (eg. More...
 

Private Attributes

std::atomic< bool > m_synced {false}
 Whether the index is in sync with the main chain. More...
 
std::atomic< const CBlockIndex * > m_best_block_index {nullptr}
 The last block in the chain that the index is in sync with. More...
 
std::thread m_thread_sync
 
CThreadInterrupt m_interrupt
 

Detailed Description

Base class for indices of blockchain data.

This implements CValidationInterface and ensures blocks are indexed sequentially according to their position in the active chain.

Definition at line 27 of file base.h.

Constructor & Destructor Documentation

◆ ~BaseIndex()

BaseIndex::~BaseIndex ( )
virtual

Destructor interrupts sync thread if running and blocks until it exits.

Definition at line 48 of file base.cpp.

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Member Function Documentation

◆ BlockConnected()

void BaseIndex::BlockConnected ( const std::shared_ptr< const CBlock > &  block,
const CBlockIndex pindex 
)
overrideprotectedvirtual

Notifies listeners of a block being connected.

Provides a vector of transactions evicted from the mempool as a result.

Called on a background thread.

Reimplemented from CValidationInterface.

Definition at line 190 of file base.cpp.

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◆ BlockUntilSyncedToCurrentChain()

bool BaseIndex::BlockUntilSyncedToCurrentChain ( ) const

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.

Definition at line 271 of file base.cpp.

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◆ ChainStateFlushed()

void BaseIndex::ChainStateFlushed ( const CBlockLocator locator)
overrideprotectedvirtual

Notifies listeners of the new active block chain on-disk.

Prior to this callback, any updates are not guaranteed to persist on disk (ie clients need to handle shutdown/restart safety by being able to understand when some updates were lost due to unclean shutdown).

When this callback is invoked, the validation changes done by any prior callback are guaranteed to exist on disk and survive a restart, including an unclean shutdown.

Provides a locator describing the best chain, which is likely useful for storing current state on disk in client DBs.

Called on a background thread.

Reimplemented from CValidationInterface.

Definition at line 232 of file base.cpp.

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◆ Commit()

bool BaseIndex::Commit ( )
private

Write the current index state (eg.

chain block locator and subclass-specific items) to disk.

Recommendations for error handling: If called on a successor of the previous committed best block in the index, the index can continue processing without risk of corruption, though the index state will need to catch up from further behind on reboot. If the new state is not a successor of the previous state (due to a chain reorganization), the index must halt until Commit succeeds or else it could end up getting corrupted.

Definition at line 158 of file base.cpp.

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◆ CommitInternal()

bool BaseIndex::CommitInternal ( CDBBatch batch)
protectedvirtual

Virtual method called internally by Commit that can be overridden to atomically commit more index state.

Reimplemented in BlockFilterIndex.

Definition at line 167 of file base.cpp.

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◆ GetDB()

virtual DB& BaseIndex::GetDB ( ) const
protectedpure virtual

Implemented in BlockFilterIndex, and TxIndex.

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◆ GetName()

virtual const char* BaseIndex::GetName ( ) const
protectedpure virtual

Get the name of the index for display in logs.

Implemented in BlockFilterIndex, and TxIndex.

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◆ GetSummary()

IndexSummary BaseIndex::GetSummary ( ) const

Get a summary of the index and its state.

Definition at line 323 of file base.cpp.

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◆ Init()

bool BaseIndex::Init ( )
protectedvirtual

Initialize internal state from the database and block index.

Reimplemented in BlockFilterIndex, and TxIndex.

Definition at line 54 of file base.cpp.

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◆ Interrupt()

void BaseIndex::Interrupt ( )

Definition at line 295 of file base.cpp.

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◆ Rewind()

bool BaseIndex::Rewind ( const CBlockIndex current_tip,
const CBlockIndex new_tip 
)
protectedvirtual

Rewind index to an earlier chain tip during a chain reorg.

The tip must be an ancestor of the current best block.

Reimplemented in BlockFilterIndex.

Definition at line 174 of file base.cpp.

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◆ Start()

void BaseIndex::Start ( )

Start initializes the sync state and registers the instance as a ValidationInterface so that it stays in sync with blockchain updates.

Definition at line 300 of file base.cpp.

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◆ Stop()

void BaseIndex::Stop ( )

Stops the instance from staying in sync with blockchain updates.

Definition at line 314 of file base.cpp.

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◆ ThreadSync()

void BaseIndex::ThreadSync ( )
private

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 index gets in sync, the m_synced flag is set and the BlockConnected ValidationInterface callback takes over and the sync thread exits.

Definition at line 87 of file base.cpp.

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◆ WriteBlock()

virtual bool BaseIndex::WriteBlock ( const CBlock block,
const CBlockIndex pindex 
)
inlineprotectedvirtual

Write update index entries for a newly connected block.

Reimplemented in BlockFilterIndex, and TxIndex.

Definition at line 88 of file base.h.

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Member Data Documentation

◆ m_best_block_index

std::atomic<const CBlockIndex*> BaseIndex::m_best_block_index {nullptr}
private

The last block in the chain that the index is in sync with.

Definition at line 57 of file base.h.

◆ m_interrupt

CThreadInterrupt BaseIndex::m_interrupt
private

Definition at line 60 of file base.h.

◆ m_synced

std::atomic<bool> BaseIndex::m_synced {false}
private

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.

Definition at line 54 of file base.h.

◆ m_thread_sync

std::thread BaseIndex::m_thread_sync
private

Definition at line 59 of file base.h.


The documentation for this class was generated from the following files: