CCoinsView that adds a memory cache for transactions to another CCoinsView. More...

#include <coins.h>

Inheritance diagram for CCoinsViewCache:

Collaboration diagram for CCoinsViewCache:

Public Member Functions
	CCoinsViewCache (CCoinsView *baseIn, bool deterministic=false)

	CCoinsViewCache (const CCoinsViewCache &)=delete
	By deleting the copy constructor, we prevent accidentally using it when one intends to create a cache on top of a base cache.

bool	GetCoin (const COutPoint &outpoint, Coin &coin) const override
	Retrieve the Coin (unspent transaction output) for a given outpoint.

bool	HaveCoin (const COutPoint &outpoint) const override
	Just check whether a given outpoint is unspent.

BlockHash	GetBestBlock () const override
	Retrieve the block hash whose state this CCoinsView currently represents.

void	SetBestBlock (const BlockHash &hashBlock)

bool	BatchWrite (CCoinsMap &mapCoins, const BlockHash &hashBlock, bool erase=true) override
	Do a bulk modification (multiple Coin changes + BestBlock change).

CCoinsViewCursor *	Cursor () const override
	Get a cursor to iterate over the whole state.

bool	HaveCoinInCache (const COutPoint &outpoint) const
	Check if we have the given utxo already loaded in this cache.

const Coin &	AccessCoin (const COutPoint &output) const
	Return a reference to Coin in the cache, or coinEmpty if not found.

void	AddCoin (const COutPoint &outpoint, Coin coin, bool possible_overwrite)
	Add a coin.

void	EmplaceCoinInternalDANGER (COutPoint &&outpoint, Coin &&coin)
	Emplace a coin into cacheCoins without performing any checks, marking the emplaced coin as dirty.

bool	SpendCoin (const COutPoint &outpoint, Coin *moveto=nullptr)
	Spend a coin.

bool	Flush ()
	Push the modifications applied to this cache to its base and wipe local state.

bool	Sync ()
	Push the modifications applied to this cache to its base while retaining the contents of this cache (except for spent coins, which we erase).

void	Uncache (const COutPoint &outpoint)
	Removes the UTXO with the given outpoint from the cache, if it is not modified.

unsigned int	GetCacheSize () const
	Calculate the size of the cache (in number of transaction outputs)

size_t	DynamicMemoryUsage () const
	Calculate the size of the cache (in bytes)

bool	HaveInputs (const CTransaction &tx) const
	Check whether all prevouts of the transaction are present in the UTXO set represented by this view.

void	ReallocateCache ()
	Force a reallocation of the cache map.

void	SanityCheck () const
	Run an internal sanity check on the cache data structure.

Public Member Functions inherited from CCoinsViewBacked
	CCoinsViewBacked (CCoinsView *viewIn)

std::vector< BlockHash >	GetHeadBlocks () const override
	Retrieve the range of blocks that may have been only partially written.

void	SetBackend (CCoinsView &viewIn)

size_t	EstimateSize () const override
	Estimate database size (0 if not implemented)

Public Member Functions inherited from CCoinsView
virtual	~CCoinsView ()
	As we use CCoinsViews polymorphically, have a virtual destructor.

Protected Attributes
BlockHash	hashBlock
	Make mutable so that we can "fill the cache" even from Get-methods declared as "const".

CCoinsMapMemoryResource	m_cache_coins_memory_resource {}

CCoinsMap	cacheCoins

size_t	cachedCoinsUsage

Protected Attributes inherited from CCoinsViewBacked
CCoinsView *	base

Private Member Functions
CCoinsMap::iterator	FetchCoin (const COutPoint &outpoint) const

Private Attributes
const bool	m_deterministic

Detailed Description

CCoinsView that adds a memory cache for transactions to another CCoinsView.

Definition at line 221 of file coins.h.

Constructor & Destructor Documentation

◆ CCoinsViewCache() [1/2]

CCoinsViewCache::CCoinsViewCache	(	CCoinsView *	baseIn,
		bool	deterministic = `false`
	)

Definition at line 61 of file coins.cpp.

◆ CCoinsViewCache() [2/2]

CCoinsViewCache::CCoinsViewCache ( const CCoinsViewCache & )

delete

By deleting the copy constructor, we prevent accidentally using it when one intends to create a cache on top of a base cache.

Member Function Documentation

◆ AccessCoin()

const Coin & CCoinsViewCache::AccessCoin ( const COutPoint & output ) const

Return a reference to Coin in the cache, or coinEmpty if not found.

This is more efficient than GetCoin.

Generally, do not hold the reference returned for more than a short scope. While the current implementation allows for modifications to the contents of the cache while holding the reference, this behavior should not be relied on! To be safe, best to not hold the returned reference through any other calls to this cache.

Definition at line 196 of file coins.cpp.

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◆ AddCoin()

void CCoinsViewCache::AddCoin	(	const COutPoint &	outpoint,
		Coin	coin,
		bool	possible_overwrite
	)

Add a coin.

Set possible_overwrite to true if an unspent version may already exist in the cache.

Definition at line 104 of file coins.cpp.

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◆ BatchWrite()

bool CCoinsViewCache::BatchWrite	(	CCoinsMap &	mapCoins,
		const BlockHash &	hashBlock,
		bool	erase = `true`
	)

overridevirtual

Do a bulk modification (multiple Coin changes + BestBlock change).

The passed mapCoins can be modified.

Reimplemented from CCoinsViewBacked.

Definition at line 225 of file coins.cpp.

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◆ Cursor()

CCoinsViewCursor * CCoinsViewCache::Cursor ( ) const

inlineoverridevirtual

Get a cursor to iterate over the whole state.

Reimplemented from CCoinsViewBacked.

Definition at line 253 of file coins.h.

◆ DynamicMemoryUsage()

size_t CCoinsViewCache::DynamicMemoryUsage ( ) const

Calculate the size of the cache (in bytes)

Definition at line 67 of file coins.cpp.

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◆ EmplaceCoinInternalDANGER()

void CCoinsViewCache::EmplaceCoinInternalDANGER	(	COutPoint &&	outpoint,
		Coin &&	coin
	)

Emplace a coin into cacheCoins without performing any checks, marking the emplaced coin as dirty.

NOT FOR GENERAL USE. Used only when loading coins from a UTXO snapshot.

See also: ChainstateManager::PopulateAndValidateSnapshot()

Definition at line 148 of file coins.cpp.

◆ FetchCoin()

CCoinsMap::iterator CCoinsViewCache::FetchCoin ( const COutPoint & outpoint ) const

private

Note: this is marked const, but may actually append to cacheCoins, increasing memory usage.

Definition at line 72 of file coins.cpp.

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◆ Flush()

bool CCoinsViewCache::Flush ( )

Push the modifications applied to this cache to its base and wipe local state.

Failure to call this method or Sync() before destruction will cause the changes to be forgotten. If false is returned, the state of this cache (and its backing view) will be undefined.

Definition at line 301 of file coins.cpp.

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◆ GetBestBlock()

BlockHash CCoinsViewCache::GetBestBlock ( ) const

overridevirtual

Retrieve the block hash whose state this CCoinsView currently represents.

Reimplemented from CCoinsViewBacked.

Definition at line 214 of file coins.cpp.

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◆ GetCacheSize()

unsigned int CCoinsViewCache::GetCacheSize ( ) const

Calculate the size of the cache (in number of transaction outputs)

Definition at line 342 of file coins.cpp.

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◆ GetCoin()

bool CCoinsViewCache::GetCoin	(	const COutPoint &	outpoint,
		Coin &	coin
	)		const

overridevirtual

Retrieve the Coin (unspent transaction output) for a given outpoint.

Returns true only when an unspent coin was found, which is returned in coin. When false is returned, coin's value is unspecified.

Reimplemented from CCoinsViewBacked.

Definition at line 95 of file coins.cpp.

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◆ HaveCoin()

bool CCoinsViewCache::HaveCoin ( const COutPoint & outpoint ) const

overridevirtual

Just check whether a given outpoint is unspent.

Reimplemented from CCoinsViewBacked.

Definition at line 204 of file coins.cpp.

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◆ HaveCoinInCache()

bool CCoinsViewCache::HaveCoinInCache ( const COutPoint & outpoint ) const

Check if we have the given utxo already loaded in this cache.

The semantics are the same as HaveCoin(), but no calls to the backing CCoinsView are made.

Definition at line 209 of file coins.cpp.

◆ HaveInputs()

bool CCoinsViewCache::HaveInputs ( const CTransaction & tx ) const

Check whether all prevouts of the transaction are present in the UTXO set represented by this view.

Definition at line 346 of file coins.cpp.

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◆ ReallocateCache()

void CCoinsViewCache::ReallocateCache ( )

Force a reallocation of the cache map.

This is required when downsizing the cache because the map's allocator may be hanging onto a lot of memory despite having called .clear().

See: https://stackoverflow.com/questions/42114044/how-to-release-unordered-map-memory

Definition at line 360 of file coins.cpp.

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◆ SanityCheck()

void CCoinsViewCache::SanityCheck ( ) const

Run an internal sanity check on the cache data structure.

Definition at line 371 of file coins.cpp.

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◆ SetBestBlock()

void CCoinsViewCache::SetBestBlock ( const BlockHash & hashBlock )

Definition at line 221 of file coins.cpp.

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◆ SpendCoin()

bool CCoinsViewCache::SpendCoin	(	const COutPoint &	outpoint,
		Coin *	moveto = `nullptr`
	)

Spend a coin.

Pass moveto in order to get the deleted data. If no unspent output exists for the passed outpoint, this call has no effect.

Definition at line 172 of file coins.cpp.

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◆ Sync()

bool CCoinsViewCache::Sync ( )

Push the modifications applied to this cache to its base while retaining the contents of this cache (except for spent coins, which we erase).

Failure to call this method or Flush() before destruction will cause the changes to be forgotten. If false is returned, the state of this cache (and its backing view) will be undefined.

Definition at line 314 of file coins.cpp.

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◆ Uncache()

void CCoinsViewCache::Uncache ( const COutPoint & outpoint )

Removes the UTXO with the given outpoint from the cache, if it is not modified.

Definition at line 330 of file coins.cpp.

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Member Data Documentation

◆ cacheCoins

CCoinsMap CCoinsViewCache::cacheCoins

mutableprotected

Definition at line 232 of file coins.h.

◆ cachedCoinsUsage

size_t CCoinsViewCache::cachedCoinsUsage

mutableprotected

Definition at line 235 of file coins.h.

◆ hashBlock

BlockHash CCoinsViewCache::hashBlock

mutableprotected

Make mutable so that we can "fill the cache" even from Get-methods declared as "const".

Definition at line 230 of file coins.h.

◆ m_cache_coins_memory_resource

CCoinsMapMemoryResource CCoinsViewCache::m_cache_coins_memory_resource {}

mutableprotected

Definition at line 231 of file coins.h.

◆ m_deterministic

const bool CCoinsViewCache::m_deterministic

private

Definition at line 223 of file coins.h.

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

src/coins.h
src/coins.cpp

Public Member Functions

Protected Attributes

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ CCoinsViewCache() [1/2]

◆ CCoinsViewCache() [2/2]

Member Function Documentation

◆ AccessCoin()

◆ AddCoin()

◆ BatchWrite()

◆ Cursor()

◆ DynamicMemoryUsage()

◆ EmplaceCoinInternalDANGER()

◆ FetchCoin()

◆ Flush()

◆ GetBestBlock()

◆ GetCacheSize()

◆ GetCoin()

◆ HaveCoin()

◆ HaveCoinInCache()

◆ HaveInputs()

◆ ReallocateCache()

◆ SanityCheck()

◆ SetBestBlock()

◆ SpendCoin()

◆ Sync()

◆ Uncache()

Member Data Documentation

◆ cacheCoins

◆ cachedCoinsUsage

◆ hashBlock

◆ m_cache_coins_memory_resource

◆ m_deterministic