Class representing a cache/ephemeral data store. More...

Inheritance diagram for BagOStuff:

[legend]

Collaboration diagram for BagOStuff:

[legend]

Public Member Functions
	__construct (array $params=[])
	Parameters include: More...

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

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

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

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

	clearLastError ()
	Clear the "last error" registry. More...

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

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

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

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

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

	getCurrentTime ()

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

	getLogger ()

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

	getQoS ( $flag)

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

	getSegmentationSize ()

	getSegmentedValueMaxSize ()

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

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

	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. More...

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

	lock ( $key, $timeout=6, $exptime=6, $rclass='')
	Acquire an advisory lock on a key string, exclusive to the caller. More...

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

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

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

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

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

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

	setLogger (LoggerInterface $logger)

	setMockTime (&$time)

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

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

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

Public Attributes
const	READ_LATEST = 1
	Bitfield constants for get()/getMulti(); these are only advisory. More...

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. More...

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

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

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

const	ERR_NONE = 0
	No storage medium error. More...

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

const	ERR_UNREACHABLE = 2
	Storage medium could not be reached. More...

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

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

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

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

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

const	QOS_EMULATION_SQL = 1
	Fallback disk-based SQL store. More...

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

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

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

	determineKeyPrefixForStats ( $key)

	fieldHasFlags ( $field, $flags)

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

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

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

Protected Attributes
callable null	$asyncHandler

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

string	$keyspace
	Default keyspace; used by makeKey() More...

LoggerInterface	$logger

StatsdDataFactoryInterface	$stats

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

Private Attributes
float null	$wallClockOverride

const	WRAPPER_COLLECTION_CALLBACK = 1
	Key to the callback that extracts collection names from cache wrapper keys. More...

const	WRAPPER_STATS_GROUP = 0
	Key to the metric group to use for the relevant cache wrapper. More...

Detailed Description

Class representing a cache/ephemeral data store.

This interface is intended to be more or less compatible with the PHP memcached client.

Class instances should be created with an intended access scope for the dataset, such as:

a) A single PHP thread on a server (e.g. stored in a PHP variable)
b) A single application server (e.g. stored in APC or sqlite)
c) All application servers in datacenter (e.g. stored in memcached or mysql)
d) All application servers in all datacenters (e.g. stored via mcrouter or dynomite)

Callers should use the proper factory methods that yield BagOStuff instances. Site admins should make sure that the configuration for those factory methods match their access scope. BagOStuff subclasses have widely varying levels of support replication features within and among datacenters.

Subclasses should override the default "segmentationSize" field with an appropriate value. The value should not be larger than what the backing store (by default) supports. It also should be roughly informed by common performance bottlenecks (e.g. values over a certain size having poor scalability). The same goes for the "segmentedValueMaxSize" member, which limits the maximum size and chunk count (indirectly) of values.

A few notes about data consistency for BagOStuff instances:

Read operation methods, e.g. get(), should be synchronous in the local datacenter. When used with READ_LATEST, such operations should reflect any prior writes originating from the local datacenter (e.g. by avoiding replica DBs or invoking quorom reads).
Write operation methods, e.g. set(), should be synchronous in the local datacenter, with asynchronous cross-datacenter replication. This replication can be either "best effort" or eventually consistent. When used with WRITE_SYNC, such operations will wait until all datacenters are updated or a timeout occurs. If the write succeeded, then any subsequent get() operations with READ_LATEST, regardless of datacenter, should reflect the changes.
Locking operation methods, e.g. lock(), unlock(), and getScopedLock(), should only apply to the local datacenter.
Any set of single-key write operation method calls originating from a single datacenter should observe "best effort" linearizability. Any set of single-key write operations using WRITE_SYNC, regardless of the datacenter, should observe "best effort" linearizability. In this context, "best effort" means that consistency holds as long as connectivity is strong, network latency is low, and there are no relevant storage server failures. Per https://en.wikipedia.org/wiki/PACELC_theorem, the store should act as a PA/EL distributed system for these operations.

Stability: stable: to extend

Definition at line 81 of file BagOStuff.php.

Constructor & Destructor Documentation

◆ __construct()

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

Parameters include:

keyspace: Keyspace to use for keys in makeKey(). [Default: "local"]
asyncHandler: Callable to use for scheduling tasks after the web request ends. In CLI mode, it should run the task immediately. [Default: null]
stats: IStatsdDataFactory instance. [optional]
logger: Psr\Log\LoggerInterface instance. [optional]
Parameters

array $params

Reimplemented in WinCacheBagOStuff, MediumSpecificBagOStuff, EmptyBagOStuff, APCUBagOStuff, and MemcachedBagOStuff.

Definition at line 154 of file BagOStuff.php.

References setLogger().

Member Function Documentation

◆ add()

BagOStuff::add	(	$key,
		$value,
		$exptime = `0`,
		$flags = `0`
	)

abstract

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 in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ addBusyCallback()

BagOStuff::addBusyCallback ( callable $workCallback )

abstract

Let a callback be run to avoid wasting time on special blocking calls.

The callbacks may or may not be called ever, in any particular order. They are likely to be invoked when something WRITE_SYNC is used used. They should follow a caching pattern as shown below, so that any code using the work will get it's result no matter what happens.

$result = null;
$workCallback = function () use ( &$result ) {
    if ( !$result ) {
        $result = ....
    }
    return $result;
}

Parameters

callable $workCallback

Since: 1.28

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ changeTTL()

BagOStuff::changeTTL	(	$key,
		$exptime = `0`,
		$flags = `0`
	)

abstract

Change the expiration on a key if it exists.

If an expiry in the past is given then the key will immediately be expired

For large values written using WRITE_ALLOW_SEGMENTS, this only changes the TTL of the main segment list key. While lowering the TTL of the segment list key has the effect of functionally lowering the TTL of the key, it might leave unused blobs in cache for longer. Raising the TTL of such keys is not effective, since the expiration of a single segment key effectively expires the entire value.

Parameters

string	$key
int	$exptime	TTL or UNIX timestamp
int	$flags	Bitfield of BagOStuff::WRITE_* constants (since 1.33)

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

Since: 1.28

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ changeTTLMulti()

BagOStuff::changeTTLMulti	(	array	$keys,
			$exptime,
			$flags = `0`
	)

abstract

Change the expiration of multiple keys that exist.

See also: BagOStuff::changeTTL()

Parameters

string[]	$keys	List of keys
int	$exptime	TTL or UNIX timestamp
int	$flags	Bitfield of BagOStuff::WRITE_* constants (since 1.33)

Returns: bool Success

Since: 1.34

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ clearLastError()

BagOStuff::clearLastError ( )

abstract

Clear the "last error" registry.

Since: 1.23

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ componentsFromGenericKey()

BagOStuff::componentsFromGenericKey ( $key )

finalprotected

Extract the components from a "generic" reversible cache key.

See also: BagOStuff::genericKeyFromComponents()

Parameters

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

Returns: string[] Key components for keyspace, collection name, and IDs

Since: 1.35

Definition at line 688 of file BagOStuff.php.

◆ convertGenericKey()

BagOStuff::convertGenericKey ( $key )

abstractprotected

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 in RESTBagOStuff, ReplicatedBagOStuff, RedisBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, HashBagOStuff, EmptyBagOStuff, CachedBagOStuff, and APCUBagOStuff.

Referenced by proxyCall().

◆ decr()

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

abstract

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 in SqlBagOStuff, WinCacheBagOStuff, RESTBagOStuff, ReplicatedBagOStuff, RedisBagOStuff, MultiWriteBagOStuff, MemcachedPhpBagOStuff, MemcachedPeclBagOStuff, HashBagOStuff, EmptyBagOStuff, CachedBagOStuff, and APCUBagOStuff.

◆ delete()

BagOStuff::delete	(	$key,
		$flags = `0`
	)

abstract

Delete an item.

For large values written using WRITE_ALLOW_SEGMENTS, this only deletes the main segment list key unless WRITE_PRUNE_SEGMENTS is in the flags. While deleting the segment list key has the effect of functionally deleting the key, it leaves unused blobs in cache.

Parameters

string $key

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

Parameters

int $flags Bitfield of BagOStuff::WRITE_* constants

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ deleteMulti()

BagOStuff::deleteMulti	(	array	$keys,
			$flags = `0`
	)

abstract

Batch deletion.

This does not support WRITE_ALLOW_SEGMENTS to avoid excessive read I/O

WRITE_BACKGROUND can be used for bulk deletion where the response is not vital

Parameters

string[]	$keys	List of keys
int	$flags	Bitfield of BagOStuff::WRITE_* constants

Returns: bool Success

Since: 1.33

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ deleteObjectsExpiringBefore()

BagOStuff::deleteObjectsExpiringBefore	(		$timestamp,
		callable	$progress = `null`,
			$limit = `INF`,
		string	$tag = `null`
	)

abstract

Delete all objects expiring before a certain date.

Parameters

string \| int	$timestamp	The reference date in MW or TS_UNIX format
callable \| null	$progress	Optional, a function which will be called regularly during long-running operations with the percentage progress as the first parameter. [optional]
int	$limit	Maximum number of keys to delete [default: INF]
string \| null	$tag	Tag to purge a single shard only. This is only supported when server tags are used in configuration.

Returns: bool Success; false if unimplemented

Reimplemented in SqlBagOStuff, ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ determineKeyPrefixForStats()

BagOStuff::determineKeyPrefixForStats ( $key )

protected

Parameters

string $key Key generated by an IStoreKeyEncoder instance

Returns: string A stats prefix to describe this class of key (e.g. "objectcache.file")

Definition at line 755 of file BagOStuff.php.

References WRAPPER_COLLECTION_CALLBACK, and WRAPPER_STATS_GROUP.

◆ fieldHasFlags()

BagOStuff::fieldHasFlags	(	$field,
		$flags
	)

finalprotected

Parameters

int	$field
int	$flags

Returns: bool

Since: 1.34

Definition at line 570 of file BagOStuff.php.

Referenced by CachedBagOStuff\changeTTLMulti(), CachedBagOStuff\delete(), MediumSpecificBagOStuff\delete(), CachedBagOStuff\deleteMulti(), MemcachedPeclBagOStuff\doDeleteMulti(), MemcachedPeclBagOStuff\doSetMulti(), MultiWriteBagOStuff\get(), ReplicatedBagOStuff\get(), ReplicatedBagOStuff\getMulti(), SqlBagOStuff\modifyBlobs(), CachedBagOStuff\set(), CachedBagOStuff\setMulti(), and MultiWriteBagOStuff\useAsyncSecondaryWrites().

◆ genericKeyFromComponents()

BagOStuff::genericKeyFromComponents ( $components )

finalprotected

At a minimum, there must be a keyspace and collection name component.

Parameters

string|int ...$components Key components for keyspace, collection name, and IDs

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

Since: 1.35

Definition at line 662 of file BagOStuff.php.

Referenced by CachedBagOStuff\makeGlobalKey(), MultiWriteBagOStuff\makeGlobalKey(), ReplicatedBagOStuff\makeGlobalKey(), CachedBagOStuff\makeKey(), MultiWriteBagOStuff\makeKey(), ReplicatedBagOStuff\makeKey(), APCUBagOStuff\makeKeyInternal(), CachedBagOStuff\makeKeyInternal(), EmptyBagOStuff\makeKeyInternal(), HashBagOStuff\makeKeyInternal(), MultiWriteBagOStuff\makeKeyInternal(), RedisBagOStuff\makeKeyInternal(), ReplicatedBagOStuff\makeKeyInternal(), and RESTBagOStuff\makeKeyInternal().

◆ get()

BagOStuff::get	(	$key,
		$flags = `0`
	)

abstract

Get an item with the given key.

If the key includes a deterministic input hash (e.g. the key can only have the correct value) or complete staleness checks are handled by the caller (e.g. nothing relies on the TTL), then the READ_VERIFIED flag should be set. This lets tiered backends know they can safely upgrade a cached value to higher tiers using standard TTLs.

Parameters

string	$key
int	$flags	Bitfield of BagOStuff::READ_* constants [optional]

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

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

Referenced by McTest\execute(), and CachedBagOStuff\get().

◆ getCurrentTime()

BagOStuff::getCurrentTime ( )

Access: internal: For testing only

Returns: float UNIX timestamp

Definition at line 781 of file BagOStuff.php.

Referenced by SqlBagOStuff\deleteServerObjectsExpiringBefore(), SqlBagOStuff\doChangeTTL(), SqlBagOStuff\doChangeTTLMulti(), SqlBagOStuff\doDelete(), SqlBagOStuff\doDeleteMulti(), SqlBagOStuff\doSet(), SqlBagOStuff\doSetMulti(), HashBagOStuff\expire(), SqlBagOStuff\expireAll(), SqlBagOStuff\fetchBlobs(), MemcachedBagOStuff\fixExpiry(), SqlBagOStuff\getConnection(), ReplicatedBagOStuff\hadRecentSessionWrite(), SqlBagOStuff\incrWithInit(), SqlBagOStuff\markServerDown(), SqlBagOStuff\occasionallyGarbageCollect(), and ReplicatedBagOStuff\remarkRecentSessionWrite().

◆ getLastError()

BagOStuff::getLastError ( )

abstract

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

Returns: int ERR_* constant for the "last error" registry

Since: 1.23

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ getLogger()

BagOStuff::getLogger ( )

Since: 1.35

Returns: LoggerInterface

Definition at line 173 of file BagOStuff.php.

References $logger.

◆ getMulti()

BagOStuff::getMulti	(	array	$keys,
			$flags = `0`
	)

abstract

Get an associative array containing the item for each of the keys that have items.

Parameters

string[]	$keys	List of keys
int	$flags	Bitfield; supports READ_LATEST [optional]

Returns: mixed[] Map of (key => value) for existing keys

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ getQoS()

BagOStuff::getQoS ( $flag )

Parameters

int $flag ATTR_* class constant

Returns: int QOS_* class constant

Since: 1.28

Reimplemented in MediumSpecificBagOStuff.

Definition at line 544 of file BagOStuff.php.

References Wikimedia\LightweightObjectStore\StorageAwareness\QOS_UNKNOWN.

◆ getScopedLock()

BagOStuff::getScopedLock	(	$key,
		$timeout = `6`,
		$expiry = `30`,
		$rclass = `''`
	)

final

Get a lightweight exclusive self-unlocking lock.

Note that the same lock cannot be acquired twice.

This is useful for task de-duplication or to avoid obtrusive (though non-corrupting) DB errors like INSERT key conflicts or deadlocks when using LOCK IN SHARE MODE.

Parameters

string	$key
int	$timeout	Lock wait timeout; 0 for non-blocking [optional]
int	$expiry	Lock expiry [optional]; 1 day maximum
string	$rclass	Allow reentry if set and the current lock used this value

Returns: ScopedCallback|null Returns null on failure

Since: 1.26

Definition at line 335 of file BagOStuff.php.

References lock(), and unlock().

◆ getSegmentationSize()

BagOStuff::getSegmentationSize ( )

Returns: int|float The chunk size, in bytes, of segmented objects (INF for no limit)

Since: 1.34

Reimplemented in MediumSpecificBagOStuff.

Definition at line 552 of file BagOStuff.php.

◆ getSegmentedValueMaxSize()

BagOStuff::getSegmentedValueMaxSize ( )

Returns: int|float Maximum total segmented object size in bytes (INF for no limit)

Since: 1.34

Reimplemented in MediumSpecificBagOStuff.

Definition at line 560 of file BagOStuff.php.

◆ getWithSetCallback()

BagOStuff::getWithSetCallback	(	$key,
		$exptime,
		$callback,
		$flags = `0`
	)

final

Get an item with the given key, regenerating and setting it if not found.

The callback can take $exptime as argument by reference and modify it. Nothing is stored nor deleted if the callback returns false.

Parameters

string	$key
int	$exptime	Time-to-live (seconds)
callable	$callback	Callback that derives the new value
int	$flags	Bitfield of BagOStuff::READ_* or BagOStuff::WRITE_* constants [optional]

Returns: mixed The cached value if found or the result of $callback otherwise

Since: 1.27

Definition at line 190 of file BagOStuff.php.

◆ incr()

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

abstract

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 in SqlBagOStuff, WinCacheBagOStuff, RESTBagOStuff, ReplicatedBagOStuff, RedisBagOStuff, MultiWriteBagOStuff, MemcachedPhpBagOStuff, MemcachedPeclBagOStuff, HashBagOStuff, EmptyBagOStuff, CachedBagOStuff, and APCUBagOStuff.

◆ incrWithInit()

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

abstract

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 in SqlBagOStuff, ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, EmptyBagOStuff, CachedBagOStuff, and APCUBagOStuff.

◆ isKeyGlobal()

BagOStuff::isKeyGlobal ( $key )

Check whether a cache key is in the global keyspace.

Parameters

string $key

Returns: bool

Since: 1.35

Definition at line 535 of file BagOStuff.php.

◆ lock()

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

abstract

Acquire an advisory lock on a key string, exclusive to the caller.

Parameters

string	$key
int	$timeout	Lock wait timeout; 0 for non-blocking [optional]
int	$exptime	Lock time-to-live in seconds; 1 day maximum [optional]
string	$rclass	If this thread already holds the lock, and the lock was acquired using the same value for this parameter, then return true and use reference counting so that only the unlock() call from the outermost lock() caller actually releases the lock (note that only the outermost time-to-live is used) [optional]

Returns: bool Success

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

Referenced by getScopedLock().

◆ makeGlobalKey()

BagOStuff::makeGlobalKey	(	$collection,
		$components
	)

abstract

Make a cache key for the default keyspace and given components.

See also: IStoreKeyEncoder::makeGlobalKey()

Parameters

string	$collection	Key collection name component
	string\|int	...$components Additional, ordered, key components for entity IDs

Returns: string Colon-separated, keyspace-prepended, ordered list of encoded components

Since: 1.27

Implements IStoreKeyEncoder.

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

Referenced by Wikimedia\Rdbms\ChronologyProtector\__construct(), and ExtensionRegistry\makeCacheKey().

◆ makeKey()

BagOStuff::makeKey	(	$collection,
		$components
	)

abstract

Make a cache key for the global keyspace and given components.

See also: IStoreKeyEncoder::makeKey()

Parameters

string	$collection	Key collection name component
	string\|int	...$components Additional, ordered, key components for entity IDs

Returns: string Colon-separated, keyspace-prepended, ordered list of encoded components

Since: 1.27

Implements IStoreKeyEncoder.

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

Referenced by CryptHKDF\__construct(), and UploadBase\getUploadSessionKey().

◆ makeKeyInternal()

BagOStuff::makeKeyInternal	(	$keyspace,
		$components
	)

abstract

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 in SqlBagOStuff, WinCacheBagOStuff, RESTBagOStuff, ReplicatedBagOStuff, RedisBagOStuff, MultiWriteBagOStuff, MemcachedBagOStuff, HashBagOStuff, EmptyBagOStuff, CachedBagOStuff, and APCUBagOStuff.

◆ merge()

BagOStuff::merge	(		$key,
		callable	$callback,
			$exptime = `0`,
			$attempts = `10`,
			$flags = `0`
	)

abstract

Merge changes into the existing cache value (possibly creating a new one)

The callback function returns the new value given the current value (which will be false if not present), and takes the arguments: (this BagOStuff, cache key, current value, TTL). The TTL parameter is reference set to $exptime. It can be overriden in the callback. Nothing is stored nor deleted if the callback returns false.

Parameters

string	$key
callable	$callback	Callback method to be executed
int	$exptime	Either an interval in seconds or a unix timestamp for expiry
int	$attempts	The amount of times to attempt a merge in case of failure
int	$flags	Bitfield of BagOStuff::WRITE_* constants

Returns: bool Success

Exceptions

InvalidArgumentException

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, EmptyBagOStuff, and CachedBagOStuff.

◆ mergeFlagMaps()

BagOStuff::mergeFlagMaps ( array $bags )

finalprotected

Merge the flag maps of one or more BagOStuff objects into a "lowest common denominator" map.

Parameters

BagOStuff[] $bags

Returns: int[] Resulting flag map (class ATTR_* constant => class QOS_* constant)

Definition at line 580 of file BagOStuff.php.

Referenced by MultiWriteBagOStuff\__construct(), and ReplicatedBagOStuff\__construct().

◆ proxyCall()

BagOStuff::proxyCall	(		$method,
			$arg0Sig,
			$resSig,
		array	$genericArgs
	)

protected

Call a method on behalf of wrapper BagOStuff instance that uses "generic" keys.

Parameters

string	$method	Name of a non-final public method that reads/changes keys
int	$arg0Sig	BagOStuff::ARG0_* constant describing argument 0
int	$resSig	BagOStuff::RES_* constant describing the return value
array	$genericArgs	Method arguments passed to the wrapper instance

Returns: mixed Method result with any resulting cache keys remapped to "generic" keys

Definition at line 712 of file BagOStuff.php.

References convertGenericKey().

◆ registerWrapperInfoForStats()

BagOStuff::registerWrapperInfoForStats	(	string	$prefixComponent,
		string	$statsGroup,
		callable	$collectionCallback
	)

Register info about a caching layer class that uses BagOStuff as a backing store.

Object cache wrappers are classes that implement generic caching/storage functionality, use a BagOStuff instance as the backing store, and implement IStoreKeyEncoder with the same "generic" style key encoding as BagOStuff. Such wrappers transform keys before passing them to BagOStuff methods; a wrapper-specific prefix component will be prepended along with other possible additions. Transformed keys still use the "generic" BagOStuff encoding.

The provided callback takes a transformed key, having the specified prefix component, and extracts the key collection name. For sanity, the callback must be able to handle keys that bear the prefix (by coincidence) but do not originate from the wrapper class.

Calls to this method should be idempotent.

Parameters

string	$prefixComponent	Key prefix component used by the wrapper
string	$statsGroup	Stats group to use for metrics from this wrapper
callable	$collectionCallback	Static callback that gets the key collection name

Access: internal: For use with BagOStuff and WANObjectCache only

Since: 1.36

Definition at line 644 of file BagOStuff.php.

◆ set()

BagOStuff::set	(	$key,
		$value,
		$exptime = `0`,
		$flags = `0`
	)

abstract

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 in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ setLogger()

BagOStuff::setLogger ( LoggerInterface $logger )

Parameters

LoggerInterface $logger

Returns: void

Reimplemented in RESTBagOStuff.

Definition at line 165 of file BagOStuff.php.

References $logger.

Referenced by __construct().

◆ setMockTime()

BagOStuff::setMockTime ( & $time )

Access: internal: For testing only

Parameters

float | null &$time Mock UNIX timestamp

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, and CachedBagOStuff.

Definition at line 790 of file BagOStuff.php.

◆ setMulti()

BagOStuff::setMulti	(	array	$valueByKey,
			$exptime = `0`,
			$flags = `0`
	)

abstract

Batch insertion/replace.

This does not support WRITE_ALLOW_SEGMENTS to avoid excessive read I/O

WRITE_BACKGROUND can be used for bulk insertion where the response is not vital

Parameters

mixed[]	$valueByKey	Map of (key => value)
int	$exptime	Either an interval in seconds or a unix timestamp for expiry
int	$flags	Bitfield of BagOStuff::WRITE_* constants (since 1.33)

Returns: bool Success

Since: 1.24

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ setNewPreparedValues()

BagOStuff::setNewPreparedValues ( array $valueByKey )

abstract

Make a "generic" reversible cache key from the given components.

All previously prepared values will be cleared. Each of the new prepared values will be individually cleared as they get used by write operations for that key. This is done to avoid unchecked growth in PHP memory usage.

Example usage:

$valueByKey = [ $key1 => $value1, $key2 => $value2, $key3 => $value3 ];
$cache->setNewPreparedValues( $valueByKey );
$cache->set( $key1, $value1, $cache::TTL_HOUR );
$cache->setMulti( [ $key2 => $value2, $key3 => $value3 ], $cache::TTL_HOUR );

This is only useful if the caller needs an estimate of the serialized object sizes. The caller cannot know the serialization format and even if it did, it could be expensive to serialize complex values twice just to get the size information before writing them to cache. This method solves both problems by making the cache instance do the serialization and having it reuse the result when the cache write happens.

Parameters

array $valueByKey Map of (cache key => PHP variable value to serialize)

Returns: int[]|null[] Corresponding list of size estimates (null for invalid values)

Since: 1.35

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MemcachedPeclBagOStuff, MediumSpecificBagOStuff, HashBagOStuff, and CachedBagOStuff.

◆ unlock()

BagOStuff::unlock ( $key )

abstract

Release an advisory lock on a key string.

Parameters

string $key

Returns: bool Success

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

Referenced by getScopedLock().

Member Data Documentation

◆ $asyncHandler

callable null BagOStuff::$asyncHandler

protected

Definition at line 92 of file BagOStuff.php.

Referenced by MultiWriteBagOStuff\callKeyWriteMethodOnTierCaches(), and SqlBagOStuff\occasionallyGarbageCollect().

◆ $attrMap

int [] BagOStuff::$attrMap = []

protected

Map of (ATTR_* class constant => QOS_* class constant)

Definition at line 100 of file BagOStuff.php.

◆ $keyspace

string BagOStuff::$keyspace

protected

Default keyspace; used by makeKey()

Definition at line 103 of file BagOStuff.php.

Referenced by APCUBagOStuff\makeKeyInternal(), CachedBagOStuff\makeKeyInternal(), EmptyBagOStuff\makeKeyInternal(), HashBagOStuff\makeKeyInternal(), MemcachedBagOStuff\makeKeyInternal(), MultiWriteBagOStuff\makeKeyInternal(), RedisBagOStuff\makeKeyInternal(), ReplicatedBagOStuff\makeKeyInternal(), RESTBagOStuff\makeKeyInternal(), WinCacheBagOStuff\makeKeyInternal(), and SqlBagOStuff\makeKeyInternal().

◆ $logger

LoggerInterface BagOStuff::$logger

protected

Definition at line 90 of file BagOStuff.php.

Referenced by getLogger(), setLogger(), and RESTBagOStuff\setLogger().

◆ $stats

StatsdDataFactoryInterface BagOStuff::$stats

protected

Definition at line 88 of file BagOStuff.php.

◆ $wallClockOverride

float null BagOStuff::$wallClockOverride

private

Definition at line 106 of file BagOStuff.php.

◆ $wrapperInfoByPrefix

array<string,array> BagOStuff::$wrapperInfoByPrefix = []

protected

Cache key processing callbacks and info for metrics.

Definition at line 97 of file BagOStuff.php.

◆ READ_LATEST

const BagOStuff::READ_LATEST = 1

Bitfield constants for get()/getMulti(); these are only advisory.

Definition at line 109 of file BagOStuff.php.

Referenced by RESTBagOStuff\incr().

◆ READ_VERIFIED

const BagOStuff::READ_VERIFIED = 2

Definition at line 110 of file BagOStuff.php.

Referenced by ParserCache\get(), and ParserCache\getMetadata().

◆ WRAPPER_COLLECTION_CALLBACK

const BagOStuff::WRAPPER_COLLECTION_CALLBACK = 1

private

Key to the callback that extracts collection names from cache wrapper keys.

Definition at line 142 of file BagOStuff.php.

Referenced by determineKeyPrefixForStats().

◆ WRAPPER_STATS_GROUP

const BagOStuff::WRAPPER_STATS_GROUP = 0

private

Key to the metric group to use for the relevant cache wrapper.

Definition at line 140 of file BagOStuff.php.

Referenced by determineKeyPrefixForStats().

◆ WRITE_ALLOW_SEGMENTS

const BagOStuff::WRITE_ALLOW_SEGMENTS = 16

Definition at line 114 of file BagOStuff.php.

Referenced by ParserCache\save(), MediaWiki\Storage\PageEditStash\stashInputText(), and MediaWiki\Storage\PageEditStash\storeStashValue().

◆ WRITE_BACKGROUND

const BagOStuff::WRITE_BACKGROUND = 64

Definition at line 116 of file BagOStuff.php.

Referenced by Wikimedia\DependencyStore\KeyValueDependencyStore\remove(), Wikimedia\DependencyStore\KeyValueDependencyStore\renew(), and Wikimedia\DependencyStore\KeyValueDependencyStore\storeMulti().

◆ WRITE_CACHE_ONLY

const BagOStuff::WRITE_CACHE_ONLY = 8

Definition at line 113 of file BagOStuff.php.

Referenced by CachedBagOStuff\get(), and MediaWiki\Session\SessionBackend\save().

◆ WRITE_PRUNE_SEGMENTS

const BagOStuff::WRITE_PRUNE_SEGMENTS = 32

Definition at line 115 of file BagOStuff.php.

Referenced by MediaWiki\Storage\PageEditStash\pruneExcessStashedEntries().

◆ WRITE_SYNC

const BagOStuff::WRITE_SYNC = 4

Bitfield constants for set()/merge(); these are only advisory.

Definition at line 112 of file BagOStuff.php.

Referenced by MediaWiki\Session\SessionBackend\save().

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

includes/libs/objectcache/BagOStuff.php

Public Member Functions

Public Attributes

Protected Member Functions

Protected Attributes

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ __construct()

Member Function Documentation

◆ add()

◆ addBusyCallback()

◆ changeTTL()

◆ changeTTLMulti()

◆ clearLastError()

◆ componentsFromGenericKey()

◆ convertGenericKey()

◆ decr()

◆ delete()

◆ deleteMulti()

◆ deleteObjectsExpiringBefore()

◆ determineKeyPrefixForStats()

◆ fieldHasFlags()

◆ genericKeyFromComponents()

◆ get()

◆ getCurrentTime()

◆ getLastError()

◆ getLogger()

◆ getMulti()

◆ getQoS()

◆ getScopedLock()

◆ getSegmentationSize()

◆ getSegmentedValueMaxSize()

◆ getWithSetCallback()

◆ incr()

◆ incrWithInit()

◆ isKeyGlobal()

◆ lock()

◆ makeGlobalKey()

◆ makeKey()

◆ makeKeyInternal()

◆ merge()

◆ mergeFlagMaps()

◆ proxyCall()

◆ registerWrapperInfoForStats()

◆ set()

◆ setLogger()

◆ setMockTime()

◆ setMulti()

◆ setNewPreparedValues()

◆ unlock()

Member Data Documentation

◆ $asyncHandler

◆ $attrMap

◆ $keyspace

◆ $logger

◆ $stats

◆ $wallClockOverride

◆ $wrapperInfoByPrefix

◆ READ_LATEST

◆ READ_VERIFIED

◆ WRAPPER_COLLECTION_CALLBACK

◆ WRAPPER_STATS_GROUP

◆ WRITE_ALLOW_SEGMENTS

◆ WRITE_BACKGROUND

◆ WRITE_CACHE_ONLY

◆ WRITE_PRUNE_SEGMENTS

◆ WRITE_SYNC