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BagOStuff Class Reference

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

Inheritance diagram for BagOStuff:
Collaboration diagram for BagOStuff:

Public Member Functions

 __construct (array $params=[])
 
 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 an item. More...
 
 changeTTLMulti (array $keys, $exptime, $flags=0)
 Change the expiration of multiple items. 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 if it exists. More...
 
 deleteMulti (array $keys, $flags=0)
 Delete a batch of items. 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. More...
 
 getCurrentTime ()
 
 getLastError ( $watchPoint=0)
 Get the "last error" registry. More...
 
 getLogger ()
 
 getMulti (array $keys, $flags=0)
 Get a batch of items. More...
 
 getQoS ( $flag)
 
 getScopedLock ( $key, $timeout=6, $exptime=30, $rclass='')
 Get a lightweight exclusive self-unlocking lock. More...
 
 getSegmentationSize ()
 
 getSegmentedValueMaxSize ()
 
 getWithSetCallback ( $key, $exptime, $callback, $flags=0)
 Get an item, 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, $step=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...
 
 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)
 Set a batch of items. More...
 
 setNewPreparedValues (array $valueByKey)
 Stage a set of new key values for storage and estimate the amount of bytes needed. More...
 
 unlock ( $key)
 Release an advisory lock on a key string. More...
 
 watchErrors ()
 Get a "watch point" token that can be used to get the "last error" to occur after now. More...
 

Public Attributes

const MAX_CONFLICTS_ONE = 1
 Abort after the first merge conflict. More...
 
const READ_LATEST = 1
 Bitfield constants for get()/getMulti(); these are only advisory. More...
 
const READ_VERIFIED = 2
 Promise that the caller handles detection of staleness. More...
 
const WRITE_ALLOW_SEGMENTS = 16
 Allow partitioning of the value if it is a large string. More...
 
const WRITE_BACKGROUND = 64
 If supported, do not block on write operation completion; instead, treat writes as succesful based on whether they could be buffered. More...
 
const WRITE_CACHE_ONLY = 8
 Bitfield constants for set()/merge(); these are only advisory. More...
 
const WRITE_PRUNE_SEGMENTS = 32
 Delete all the segments if the value is partitioned. 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 complete response to an operation. 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 to establish a connection. 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 (string $method, int $arg0Sig, int $resSig, array $genericArgs, BagOStuff $wrapper)
 Call a method on behalf of wrapper BagOStuff instance that uses "generic" keys. More...
 
 setLastError ( $error)
 Set the "last error" registry due to a problem encountered during an attempted operation. More...
 

Protected Attributes

callable null $asyncHandler
 
int[] $attrMap = []
 Map of (BagOStuff:ATTR_* constant => BagOStuff:QOS_* constant) More...
 
string $keyspace
 Default keyspace; used by makeKey() More...
 
int $lastError = self::ERR_NONE
 BagOStuff:ERR_* constant of the last error that occurred. More...
 
int $lastErrorId = 0
 Error event sequence number of the last error that occurred. More...
 
LoggerInterface $logger
 
StatsdDataFactoryInterface $stats
 
array< string, array > $wrapperInfoByPrefix = []
 Cache key processing callbacks and info for metrics. More...
 

Static Protected Attributes

static int $nextErrorMonitorId = 1
 Next sequence number to use for watch/error events. 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. 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. 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
Stability: newable

Definition at line 80 of file BagOStuff.php.

Constructor & Destructor Documentation

◆ __construct()

BagOStuff::__construct ( array  $params = [])
Stability: stable
to call
Parameters
array$paramsParameters 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]

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

Definition at line 172 of file BagOStuff.php.

References $asyncHandler, and 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$exptime
int$flagsBitfield of BagOStuff::WRITE_* constants (since 1.33)
Returns
bool Success (item created)

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.

This is hard-deprecated and non-functional since 1.39. The callback will not be called.

Parameters
callable$workCallback
Since
1.28
Deprecated:
since 1.39

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ changeTTL()

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

Change the expiration on an item.

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$key
int$exptimeTTL or UNIX timestamp
int$flagsBitfield of BagOStuff::WRITE_* constants (since 1.33)
Returns
bool Success (item found and updated)
Since
1.28

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ changeTTLMulti()

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

Change the expiration of multiple items.

See also
BagOStuff::changeTTL()
Parameters
string[]$keysList of keys
int$exptimeTTL or UNIX timestamp
int$flagsBitfield of BagOStuff::WRITE_* constants (since 1.33)
Returns
bool Success (all items found and updated)
Since
1.34

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ clearLastError()

BagOStuff::clearLastError ( )

Clear the "last error" registry.

Since
1.23
Deprecated:
Since 1.38

Definition at line 519 of file BagOStuff.php.

◆ componentsFromGenericKey()

BagOStuff::componentsFromGenericKey (   $key)
finalprotected

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

See also
BagOStuff::genericKeyFromComponents()
Parameters
string$keyKeyspace-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 729 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$keyKeyspace-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.

◆ decr()

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

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

Parameters
string$key
int$valueValue to subtract from $key (default: 1) [optional]
int$flagsBit field of class WRITE_* constants [optional]
Returns
int|bool New value or false on failure
Deprecated:
Since 1.38

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 if it exists.

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$key
int$flagsBitfield of BagOStuff::WRITE_* constants
Returns
bool Success (item deleted or not found)

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ deleteMulti()

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

Delete a batch of items.

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[]$keysList of keys
int$flagsBitfield of BagOStuff::WRITE_* constants
Returns
bool Success (items deleted and/or not found)
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$timestampThe reference date in MW or TS_UNIX format
callable | null$progressOptional, a function which will be called regularly during long-running operations with the percentage progress as the first parameter. [optional]
int | float$limitMaximum number of keys to delete [default: INF]
string | null$tagTag 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 (   $key)
protected
Parameters
string$keyKey generated by an IStoreKeyEncoder instance
Returns
string A stats prefix to describe this class of key (e.g. "objectcache.file")

Definition at line 808 of file BagOStuff.php.

◆ fieldHasFlags()

BagOStuff::fieldHasFlags (   $field,
  $flags 
)
finalprotected

◆ 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 703 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.

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$key
int$flagsBitfield 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 CachedBagOStuff\get().

◆ getCurrentTime()

◆ getLastError()

BagOStuff::getLastError (   $watchPoint = 0)

Get the "last error" registry.

The method should be invoked by a caller as part of the following pattern:

  • The caller invokes watchErrors() to get a "since token"
  • The caller invokes a sequence of cache operation methods
  • The caller invokes getLastError() with the "since token"

External callers can also invoke this method as part of the following pattern:

Parameters
int$watchPointOnly consider errors from after this "watch point" [optional]
Returns
int BagOStuff:ERR_* constant for the "last error" registry
Note
Parameters added in 1.38: $watchPoint
Since
1.23

Definition at line 509 of file BagOStuff.php.

Referenced by MemcachedPeclBagOStuff\doIncrWithInitAsync(), MemcachedPhpBagOStuff\doIncrWithInitAsync(), MemcachedPeclBagOStuff\doIncrWithInitSync(), and MemcachedPhpBagOStuff\doIncrWithInitSync().

◆ getLogger()

BagOStuff::getLogger ( )
Since
1.35
Returns
LoggerInterface

Definition at line 195 of file BagOStuff.php.

◆ getMulti()

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

Get a batch of items.

Parameters
string[]$keysList of keys
int$flagsBitfield; supports READ_LATEST [optional]
Returns
mixed[] Map of (key => value) for existing keys

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ getQoS()

BagOStuff::getQoS (   $flag)
Parameters
int$flagBagOStuff::ATTR_* constant
Returns
int BagOStuff:QOS_* constant
Since
1.28

Reimplemented in MediumSpecificBagOStuff.

Definition at line 586 of file BagOStuff.php.

◆ getScopedLock()

BagOStuff::getScopedLock (   $key,
  $timeout = 6,
  $exptime = 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$key
int$timeoutLock wait timeout; 0 for non-blocking [optional]
int$exptimeLock time-to-live [optional]; 1 day maximum
string$rclassAllow reentry if set and the current lock used this value
Returns
ScopedCallback|null Returns null on failure
Since
1.26

Definition at line 357 of file BagOStuff.php.

◆ 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 594 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 602 of file BagOStuff.php.

◆ getWithSetCallback()

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

Get an item, 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$key
int$exptimeTime-to-live (seconds)
callable$callbackCallback that derives the new value
int$flagsBitfield 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 212 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$keyKey to increase
int$valueValue to add to $key (default: 1) [optional]
int$flagsBit field of class WRITE_* constants [optional]
Returns
int|bool New value or false on failure
Deprecated:
Since 1.38

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

◆ incrWithInit()

BagOStuff::incrWithInit (   $key,
  $exptime,
  $step = 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 - $step) and $exptime are invariants for all operations to any given key. The value of $init should be at least that of $step.

The new value is returned, except if the WRITE_BACKGROUND flag is given, in which case the handler may choose to return true to indicate that the operation has been dispatched.

Parameters
string$keyKey built via makeKey() or makeGlobalKey()
int$exptimeTime-to-live (in seconds) or a UNIX timestamp expiration
int$stepAmount to increase the key value by [default: 1]
int | null$initValue to initialize the key to if it does not exist [default: $step]
int$flagsBit field of class WRITE_* constants [optional]
Returns
int|bool New value (or true if asynchronous) on success; false on failure
Since
1.24

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ 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 577 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$key
int$timeoutLock wait timeout; 0 for non-blocking [optional]
int$exptimeLock time-to-live in seconds; 1 day maximum [optional]
string$rclassIf 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.

◆ makeGlobalKey()

BagOStuff::makeGlobalKey (   $collection,
  $components 
)
abstract

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

See also
IStoreKeyEncoder::makeGlobalKey()
Parameters
string$collectionKey collection name component
string|int...$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().

◆ makeKey()

BagOStuff::makeKey (   $collection,
  $components 
)
abstract

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

See also
IStoreKeyEncoder::makeKey()
Parameters
string$collectionKey collection name component
string|int...$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().

◆ 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 overridden in the callback. Nothing is stored nor deleted if the callback returns false.

Parameters
string$key
callable$callbackCallback method to be executed
int$exptimeEither an interval in seconds or a unix timestamp for expiry
int$attemptsThe amount of times to attempt a merge in case of failure
int$flagsBitfield 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 622 of file BagOStuff.php.

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

◆ proxyCall()

BagOStuff::proxyCall ( string  $method,
int  $arg0Sig,
int  $resSig,
array  $genericArgs,
BagOStuff  $wrapper 
)
protected

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

Parameters
string$methodName of a non-final public method that reads/changes keys
int$arg0SigBagOStuff::ARG0_* constant describing argument 0
int$resSigBagOStuff::RES_* constant describing the return value
array$genericArgsMethod arguments passed to the wrapper instance
BagOStuff$wrapperThe wrapper BagOStuff instance using this result
Returns
mixed Method result with any keys remapped to "generic" keys

Definition at line 754 of file BagOStuff.php.

References setLastError().

◆ 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. 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$prefixComponentKey prefix component used by the wrapper
string$statsGroupStats group to use for metrics from this wrapper
callable$collectionCallbackStatic callback that gets the key collection name
Access: internal
For use with BagOStuff and WANObjectCache only
Since
1.36

Definition at line 685 of file BagOStuff.php.

◆ set()

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

Set an item.

Parameters
string$key
mixed$value
int$exptimeEither an interval in seconds or a unix timestamp for expiry
int$flagsBitfield of BagOStuff::WRITE_* constants
Returns
bool Success

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, MediumSpecificBagOStuff, and CachedBagOStuff.

◆ setLastError()

◆ setLogger()

BagOStuff::setLogger ( LoggerInterface  $logger)
Parameters
LoggerInterface$logger
Returns
void

Reimplemented in RESTBagOStuff.

Definition at line 187 of file BagOStuff.php.

References $logger.

Referenced by __construct().

◆ setMockTime()

BagOStuff::setMockTime ( $time)
Access: internal
For testing only
Parameters
float | null&$timeMock UNIX timestamp

Reimplemented in ReplicatedBagOStuff, MultiWriteBagOStuff, and CachedBagOStuff.

Definition at line 843 of file BagOStuff.php.

◆ setMulti()

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

Set a batch of items.

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[]$valueByKeyMap of (key => value)
int$exptimeEither an interval in seconds or a unix timestamp for expiry
int$flagsBitfield 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)

Stage a set of new key values for storage and estimate the amount of bytes needed.

Parameters
array$valueByKeyMap of (cache key => PHP variable value to serialize)
Returns
int[]|null[] Corresponding list of size estimates (null for invalid values)
Since
1.35
Deprecated:
Since 1.40

Definition at line 645 of file BagOStuff.php.

References serialize().

◆ 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.

◆ watchErrors()

BagOStuff::watchErrors ( )

Get a "watch point" token that can be used to get the "last error" to occur after now.

Returns
int A token that the current error event
Since
1.38

Definition at line 487 of file BagOStuff.php.

Referenced by MemcachedPeclBagOStuff\doIncrWithInitAsync(), MemcachedPhpBagOStuff\doIncrWithInitAsync(), MemcachedPeclBagOStuff\doIncrWithInitSync(), and MemcachedPhpBagOStuff\doIncrWithInitSync().

Member Data Documentation

◆ $asyncHandler

callable null BagOStuff::$asyncHandler
protected

Definition at line 91 of file BagOStuff.php.

Referenced by __construct().

◆ $attrMap

int [] BagOStuff::$attrMap = []
protected

Map of (BagOStuff:ATTR_* constant => BagOStuff:QOS_* constant)

Definition at line 93 of file BagOStuff.php.

◆ $keyspace

◆ $lastError

int BagOStuff::$lastError = self::ERR_NONE
protected

BagOStuff:ERR_* constant of the last error that occurred.

Definition at line 104 of file BagOStuff.php.

Referenced by MemcachedPeclBagOStuff\doIncrWithInitAsync().

◆ $lastErrorId

int BagOStuff::$lastErrorId = 0
protected

Error event sequence number of the last error that occurred.

Definition at line 106 of file BagOStuff.php.

◆ $logger

LoggerInterface BagOStuff::$logger
protected

Definition at line 89 of file BagOStuff.php.

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

◆ $nextErrorMonitorId

int BagOStuff::$nextErrorMonitorId = 1
staticprotected

Next sequence number to use for watch/error events.

Definition at line 109 of file BagOStuff.php.

◆ $stats

StatsdDataFactoryInterface BagOStuff::$stats
protected

Definition at line 87 of file BagOStuff.php.

◆ $wrapperInfoByPrefix

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

Cache key processing callbacks and info for metrics.

Definition at line 98 of file BagOStuff.php.

◆ MAX_CONFLICTS_ONE

const BagOStuff::MAX_CONFLICTS_ONE = 1

Abort after the first merge conflict.

Definition at line 136 of file BagOStuff.php.

◆ READ_LATEST

const BagOStuff::READ_LATEST = 1

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

If supported, avoid reading stale data due to replication

Definition at line 116 of file BagOStuff.php.

◆ READ_VERIFIED

const BagOStuff::READ_VERIFIED = 2

Promise that the caller handles detection of staleness.

Definition at line 118 of file BagOStuff.php.

Referenced by ParserCache\get().

◆ WRITE_ALLOW_SEGMENTS

const BagOStuff::WRITE_ALLOW_SEGMENTS = 16

Allow partitioning of the value if it is a large string.

Definition at line 124 of file BagOStuff.php.

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

◆ WRITE_BACKGROUND

const BagOStuff::WRITE_BACKGROUND = 64

If supported, do not block on write operation completion; instead, treat writes as succesful based on whether they could be buffered.

When using this flag with methods that yield item values, the boolean "true" will be used as a placeholder. The next blocking operation (e.g. typical read) will trigger a flush of the operation buffer.

Definition at line 133 of file BagOStuff.php.

Referenced by Wikimedia\WRStats\BagOStuffStatsStore\delete(), Wikimedia\WRStats\BagOStuffStatsStore\incr(), Wikimedia\DependencyStore\KeyValueDependencyStore\remove(), and Wikimedia\DependencyStore\KeyValueDependencyStore\storeMulti().

◆ WRITE_CACHE_ONLY

const BagOStuff::WRITE_CACHE_ONLY = 8

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

Only change state of the in-memory cache

Definition at line 122 of file BagOStuff.php.

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

◆ WRITE_PRUNE_SEGMENTS

const BagOStuff::WRITE_PRUNE_SEGMENTS = 32

Delete all the segments if the value is partitioned.

Definition at line 126 of file BagOStuff.php.


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