This is a wrapper for APCU's shared memory functions. More...

Inheritance diagram for APCUBagOStuff:

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Collaboration diagram for APCUBagOStuff:

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Public Member Functions
	__construct (array $params=[])

	decr ( $key, $value=1, $flags=0)
	Decrease stored value of $key by $value while preserving its TTL.

	incr ( $key, $value=1, $flags=0)
	Increase stored value of $key by $value while preserving its TTL.

	incrWithInit ( $key, $exptime, $value=1, $init=null, $flags=0)
	Increase the value of the given key (no TTL change) if it exists or create it otherwise.

	makeKeyInternal ( $keyspace, $components)
	Make a cache key for the given keyspace and components.

Public Member Functions inherited from MediumSpecificBagOStuff
	add ( $key, $value, $exptime=0, $flags=0)
	Insert an item if it does not already exist.

	addBusyCallback (callable $workCallback)
	Let a callback be run to avoid wasting time on special blocking calls.

	changeTTL ( $key, $exptime=0, $flags=0)
	Change the expiration on a key if it exists.

	changeTTLMulti (array $keys, $exptime, $flags=0)
	Change the expiration of multiple keys that exist.

	clearLastError ()
	Clear the "last error" registry.

	delete ( $key, $flags=0)
	Delete an item.

	deleteMulti (array $keys, $flags=0)
	Batch deletion.

	deleteObjectsExpiringBefore ( $timestamp, callable $progress=null, $limit=INF, string $tag=null)
	Delete all objects expiring before a certain date.

	get ( $key, $flags=0)
	Get an item with the given key.

	getLastError ()
	Get the "last error" registered; clearLastError() should be called manually.

	getMulti (array $keys, $flags=0)
	Get an associative array containing the item for each of the keys that have items.

	getQoS ( $flag)

	getSegmentationSize ()

	getSegmentedValueMaxSize ()

	lock ( $key, $timeout=6, $exptime=6, $rclass='')

	makeGlobalKey ( $collection,... $components)
	Make a cache key for the default keyspace and given components.

	makeKey ( $collection,... $components)
	Make a cache key for the global keyspace and given components.

	merge ( $key, callable $callback, $exptime=0, $attempts=10, $flags=0)
	Merge changes into the existing cache value (possibly creating a new one)

	set ( $key, $value, $exptime=0, $flags=0)
	Set an item.

	setMulti (array $valueByKey, $exptime=0, $flags=0)
	Batch insertion/replace.

	setNewPreparedValues (array $valueByKey)
	Make a "generic" reversible cache key from the given components.

	unlock ( $key)
	Release an advisory lock on a key string.

Public Member Functions inherited from BagOStuff
	getCurrentTime ()

	getLogger ()

	getScopedLock ( $key, $timeout=6, $expiry=30, $rclass='')
	Get a lightweight exclusive self-unlocking lock.

	getWithSetCallback ( $key, $exptime, $callback, $flags=0)
	Get an item with the given key, regenerating and setting it if not found.

	isKeyGlobal ( $key)
	Check whether a cache key is in the global keyspace.

	registerWrapperInfoForStats (string $prefixComponent, string $statsGroup, callable $collectionCallback)
	Register info about a caching layer class that uses BagOStuff as a backing store.

	setDebug ( $enabled)

	setLogger (LoggerInterface $logger)

	setMockTime (&$time)

Protected Member Functions
	convertGenericKey ( $key)
	Convert a "generic" reversible cache key into one for this cache.

	doAdd ( $key, $value, $exptime=0, $flags=0)
	Insert an item if it does not already exist.

	doDelete ( $key, $flags=0)
	Delete an item.

	doGet ( $key, $flags=0, &$casToken=null)

	doSet ( $key, $value, $exptime=0, $flags=0)
	Set an item.

Protected Member Functions inherited from MediumSpecificBagOStuff
	cas ( $casToken, $key, $value, $exptime=0, $flags=0)
	Check and set an item.

	debug ( $text)

	doCas ( $casToken, $key, $value, $exptime=0, $flags=0)
	Check and set an item.

	doChangeTTL ( $key, $exptime, $flags)

	doChangeTTLMulti (array $keys, $exptime, $flags=0)

	doDeleteMulti (array $keys, $flags=0)

	doGetMulti (array $keys, $flags=0)
	Get an associative array containing the item for each of the keys that have items.

	doLock ( $key, $timeout, $exptime)

	doSetMulti (array $data, $exptime=0, $flags=0)

	doUnlock ( $key)

	getExpirationAsTimestamp ( $exptime)
	Convert an optionally relative timestamp to an absolute time.

	getExpirationAsTTL ( $exptime)
	Convert an optionally absolute expiry time to a relative time.

	getSerialized ( $value, $key)
	Get the serialized form a value, using any applicable prepared value.

	guessSerialValueSize ( $value, $depth=0, &$loops=0)
	Estimate the size of a variable once serialized.

	isInteger ( $value)
	Check if a value is an integer.

	isRelativeExpiration ( $exptime)

	makeLockKey ( $key)

	makeValueOrSegmentList ( $key, $value, $exptime, $flags)
	Determine the entry (inline or segment list) to store under a key to save the value.

	mergeViaCas ( $key, callable $callback, $exptime, $attempts, $flags)

	resolveSegments ( $key, $mainValue)
	Get and reassemble the chunks of blob at the given key.

	serialize ( $value)

	setLastError ( $err)
	Set the "last error" registry.

	unserialize ( $value)

	updateOpStats (string $op, array $keyInfo)

Protected Member Functions inherited from BagOStuff
	componentsFromGenericKey ( $key)
	Extract the components from a "generic" reversible cache key.

	determineKeyPrefixForStats ( $key)

	fieldHasFlags ( $field, $flags)

	genericKeyFromComponents (... $components)
	At a minimum, there must be a keyspace and collection name component.

	mergeFlagMaps (array $bags)
	Merge the flag maps of one or more BagOStuff objects into a "lowest common denominator" map.

	proxyCall ( $method, $arg0Sig, $resSig, array $genericArgs)
	Call a method on behalf of wrapper BagOStuff instance that uses "generic" keys.

Private Attributes
bool	$nativeSerialize
	Whether to trust the APC implementation to serialization.

bool	$useIncrTTLArg

Static Private Attributes
static int	$CAS_MAX_ATTEMPTS = 100
	Max attempts for implicit CAS operations.

Additional Inherited Members
Public Attributes inherited from BagOStuff
const	READ_LATEST = 1
	Bitfield constants for get()/getMulti(); these are only advisory.

const	READ_VERIFIED = 2

const	WRITE_ALLOW_SEGMENTS = 16

const	WRITE_BACKGROUND = 64

const	WRITE_CACHE_ONLY = 8

const	WRITE_PRUNE_SEGMENTS = 32

const	WRITE_SYNC = 4
	Bitfield constants for set()/merge(); these are only advisory.

Public Attributes inherited from Wikimedia\LightweightObjectStore\StorageAwareness
const	ATTR_DURABILITY = 2
	Durability of writes; see QOS_DURABILITY_* (higher means stronger)

const	ATTR_EMULATION = 1
	Emulation/fallback mode; see QOS_EMULATION_*; higher is better.

const	ERR_NO_RESPONSE = 1
	Storage medium failed to yield a response.

const	ERR_NONE = 0
	No storage medium error.

const	ERR_UNEXPECTED = 3
	Storage medium operation failed due to usage limitations or an I/O error.

const	ERR_UNREACHABLE = 2
	Storage medium could not be reached.

const	QOS_DURABILITY_DISK = 4
	Data is saved to disk and writes do not usually block on fsync()

const	QOS_DURABILITY_NONE = 1
	Data is never saved to begin with (blackhole store)

const	QOS_DURABILITY_RDBMS = 5
	Data is saved to disk and writes usually block on fsync(), like a standard RDBMS.

const	QOS_DURABILITY_SCRIPT = 2
	Data is lost at the end of the current web request or CLI script.

const	QOS_DURABILITY_SERVICE = 3
	Data is lost once the service storing the data restarts.

const	QOS_EMULATION_SQL = 1
	Fallback disk-based SQL store.

const	QOS_UNKNOWN = INF
	Generic "unknown" value; useful for comparisons (always "good enough")

Protected Attributes inherited from MediumSpecificBagOStuff
callable[]	$busyCallbacks = []

int	$lastError = self::ERR_NONE
	ERR_* class constant.

array< string, array >	$locks = []
	Map of (key => (class, depth, expiry)

array[]	$preparedValues = []
	Map of (key => (PHP variable value, serialized value))

int	$segmentationSize
	Bytes; chunk size of segmented cache values.

int	$segmentedValueMaxSize
	Bytes; maximum total size of a segmented cache value.

int	$syncTimeout
	Seconds.

const	LOCK_DEPTH = 1

const	LOCK_EXPIRY = 3

const	LOCK_RCLASS = 0

const	LOCK_TIME = 2

const	METRIC_OP_ADD = 'add'

const	METRIC_OP_CAS = 'cas'

const	METRIC_OP_CHANGE_TTL = 'change_ttl'

const	METRIC_OP_DECR = 'decr'

const	METRIC_OP_DELETE = 'delete'

const	METRIC_OP_GET = 'get'

const	METRIC_OP_INCR = 'incr'

const	METRIC_OP_SET = 'set'

Protected Attributes inherited from BagOStuff
callable null	$asyncHandler

int[]	$attrMap = []
	Map of (ATTR_* class constant => QOS_* class constant)

bool	$debugMode = true
	Whether to send debug log entries to the SPI logger instance.

string	$keyspace
	Default keyspace; used by makeKey()

LoggerInterface	$logger

StatsdDataFactoryInterface	$stats

array< string, array >	$wrapperInfoByPrefix = []
	Cache key processing callbacks and info for metrics.

Detailed Description

This is a wrapper for APCU's shared memory functions.

Use PHP serialization to avoid bugs and easily create CAS tokens. APCu has a memory corruption bug when the serializer is set to 'default'. See T120267, and upstream bug reports:

Definition at line 36 of file APCUBagOStuff.php.

Constructor & Destructor Documentation

◆ __construct()

APCUBagOStuff::__construct ( array $params = [] )

See also

BagOStuff::__construct() Additional $params options include:

logger: Psr\Log\LoggerInterface instance
reportDupes: Whether to emit warning log messages for all keys that were requested more than once (requires an asyncHandler).
syncTimeout: How long to wait with WRITE_SYNC in seconds.
segmentationSize: The chunk size, in bytes, of segmented values. The value should not exceed the maximum size of values in the storage backend, as configured by the site administrator.
segmentedValueMaxSize: The maximum total size, in bytes, of segmented values. This should be configured to a reasonable size give the site traffic and the amount of I/O between application and cache servers that the network can handle.

Parameters

array $params @phpcs:ignore Generic.Files.LineLength

Reimplemented from MediumSpecificBagOStuff.

Definition at line 52 of file APCUBagOStuff.php.

References Wikimedia\LightweightObjectStore\StorageAwareness\ATTR_DURABILITY, Wikimedia\LightweightObjectStore\StorageAwareness\QOS_DURABILITY_NONE, Wikimedia\LightweightObjectStore\StorageAwareness\QOS_DURABILITY_SCRIPT, and Wikimedia\LightweightObjectStore\StorageAwareness\QOS_DURABILITY_SERVICE.

Member Function Documentation

◆ convertGenericKey()

APCUBagOStuff::convertGenericKey ( $key )

protected

Convert a "generic" reversible cache key into one for this cache.

See also: BagOStuff::genericKeyFromComponents()

Parameters

string $key Keyspace-prepended list of encoded components as a colon-separated value

Returns: string Keyspace-prepended list of encoded components as a colon-separated value

Reimplemented from MediumSpecificBagOStuff.

Definition at line 181 of file APCUBagOStuff.php.

◆ decr()

APCUBagOStuff::decr	(	$key,
		$value = `1`,
		$flags = `0`
	)

Decrease stored value of $key by $value while preserving its TTL.

Parameters

string	$key
int	$value	Value to subtract from $key (default: 1) [optional]
int	$flags	Bit field of class WRITE_* constants [optional]

Returns: int|bool New value or false on failure

Reimplemented from BagOStuff.

Definition at line 124 of file APCUBagOStuff.php.

References $CAS_MAX_ATTEMPTS.

◆ doAdd()

APCUBagOStuff::doAdd	(	$key,
		$value,
		$exptime = `0`,
		$flags = `0`
	)

protected

Insert an item if it does not already exist.

Parameters

string	$key
mixed	$value
int	$exptime
int	$flags	Bitfield of BagOStuff::WRITE_* constants (since 1.33)

Returns: bool Success

Reimplemented from MediumSpecificBagOStuff.

Definition at line 92 of file APCUBagOStuff.php.

References $blob, $success, MediumSpecificBagOStuff\getExpirationAsTTL(), and MediumSpecificBagOStuff\getSerialized().

◆ doDelete()

APCUBagOStuff::doDelete	(	$key,
		$flags = `0`
	)

protected

Delete an item.

Parameters

string	$key
int	$flags	Bitfield of BagOStuff::WRITE_* constants

Returns: bool True if the item was deleted or not found, false on failure

Reimplemented from MediumSpecificBagOStuff.

Definition at line 99 of file APCUBagOStuff.php.

◆ doGet()

APCUBagOStuff::doGet	(		$key,
			$flags = `0`,
		&	$casToken = `null`
	)

protected

Parameters

string	$key
int	$flags	Bitfield of BagOStuff::READ_* constants [optional]
mixed \| null	&$casToken	cas() token if MediumSpecificBagOStuff::PASS_BY_REF [returned]

Returns: mixed Returns false on failure or if the item does not exist

Reimplemented from MediumSpecificBagOStuff.

Definition at line 72 of file APCUBagOStuff.php.

References $blob, and MediumSpecificBagOStuff\unserialize().

◆ doSet()

APCUBagOStuff::doSet	(	$key,
		$value,
		$exptime = `0`,
		$flags = `0`
	)

protected

Set an item.

Parameters

string	$key
mixed	$value
int	$exptime	Either an interval in seconds or a unix timestamp for expiry
int	$flags	Bitfield of BagOStuff::WRITE_* constants

Returns: bool Success

Reimplemented from MediumSpecificBagOStuff.

Definition at line 85 of file APCUBagOStuff.php.

References $blob, $success, MediumSpecificBagOStuff\getExpirationAsTTL(), and MediumSpecificBagOStuff\getSerialized().

◆ incr()

APCUBagOStuff::incr	(	$key,
		$value = `1`,
		$flags = `0`
	)

Increase stored value of $key by $value while preserving its TTL.

Parameters

string	$key	Key to increase
int	$value	Value to add to $key (default: 1) [optional]
int	$flags	Bit field of class WRITE_* constants [optional]

Returns: int|bool New value or false on failure

Reimplemented from BagOStuff.

Definition at line 105 of file APCUBagOStuff.php.

References $CAS_MAX_ATTEMPTS.

◆ incrWithInit()

APCUBagOStuff::incrWithInit	(	$key,
		$exptime,
		$value = `1`,
		$init = `null`,
		$flags = `0`
	)

Increase the value of the given key (no TTL change) if it exists or create it otherwise.

This will create the key with the value $init and TTL $exptime instead if not present. Callers should make sure that both ($init - $value) and $exptime are invariants for all operations to any given key. The value of $init should be at least that of $value.

Parameters

string	$key	Key built via makeKey() or makeGlobalKey()
int	$exptime	Time-to-live (in seconds) or a UNIX timestamp expiration
int	$value	Amount to increase the key value by [default: 1]
int \| null	$init	Value to initialize the key to if it does not exist [default: $value]
int	$flags	Bit field of class WRITE_* constants [optional]

Returns: int|bool New value or false on failure

Since: 1.24

Reimplemented from MediumSpecificBagOStuff.

Definition at line 143 of file APCUBagOStuff.php.

References $CAS_MAX_ATTEMPTS, $success, and MediumSpecificBagOStuff\getExpirationAsTTL().

◆ makeKeyInternal()

APCUBagOStuff::makeKeyInternal	(	$keyspace,
		$components
	)

Make a cache key for the given keyspace and components.

Long components might be converted to respective hashes due to size constraints. In extreme cases, all of them might be combined into a single hash component.

Access: internal: This method should not be used outside of BagOStuff (since 1.36)

Parameters

string	$keyspace	Keyspace component
string[] \| int[]	$components	Key components (key collection name first)

Returns: string Keyspace-prepended list of encoded components as a colon-separated value

Since: 1.27

Reimplemented from BagOStuff.

Definition at line 177 of file APCUBagOStuff.php.

References BagOStuff\$keyspace, and BagOStuff\genericKeyFromComponents().

Member Data Documentation

◆ $CAS_MAX_ATTEMPTS

int APCUBagOStuff::$CAS_MAX_ATTEMPTS = 100

staticprivate

Max attempts for implicit CAS operations.

Definition at line 50 of file APCUBagOStuff.php.

Referenced by decr(), incr(), and incrWithInit().

◆ $nativeSerialize

bool APCUBagOStuff::$nativeSerialize

private

Whether to trust the APC implementation to serialization.

Definition at line 38 of file APCUBagOStuff.php.

◆ $useIncrTTLArg

bool APCUBagOStuff::$useIncrTTLArg

private

Definition at line 40 of file APCUBagOStuff.php.

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

includes/libs/objectcache/APCUBagOStuff.php

Public Member Functions

Protected Member Functions

Private Attributes

Static Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ __construct()

Member Function Documentation

◆ convertGenericKey()

◆ decr()

◆ doAdd()

◆ doDelete()

◆ doGet()

◆ doSet()

◆ incr()

◆ incrWithInit()

◆ makeKeyInternal()

Member Data Documentation

◆ $CAS_MAX_ATTEMPTS

◆ $nativeSerialize

◆ $useIncrTTLArg