PoolCounterWork Class Reference

Class for dealing with PoolCounters using class members. More...

Inheritance diagram for PoolCounterWork:

Public Member Functions
	__construct (string $type, string $key, PoolCounter $poolCounter=null)
	doWork ()
	Actually perform the work, caching it if needed. More...
	error ( $status)
	Do something with the error, like showing it to the user. More...
	execute ( $skipcache=false)
	Get the result of the work (whatever it is), or the result of the error() function. More...
	fallback ( $fast)
	A work not so good (eg. More...
	getCachedWork ()
	Retrieve the work from cache. More...
	logError ( $status)
	Log an error. More...

Protected Member Functions
	isFastStaleEnabled ()
	Should fast stale mode be used? More...

Protected Attributes
bool	$cacheable = false
string	$type = 'generic'

Detailed Description

Class for dealing with PoolCounters using class members.

Definition at line 26 of file PoolCounterWork.php.

Constructor & Destructor Documentation

__construct()

PoolCounterWork::__construct	(	string	$type,
		string	$key,
		PoolCounter	$poolCounter = null
	)

Parameters

string	$type	The class of actions to limit concurrency for (task type)
string	$key	Key that identifies the queue this work is placed on
PoolCounter | null	$poolCounter

Definition at line 39 of file PoolCounterWork.php.

References $type.

Member Function Documentation

doWork()

PoolCounterWork::doWork ( )

abstract

Actually perform the work, caching it if needed.

Returns

mixed|false Work result or false

Reimplemented in PoolWorkArticleViewOld, PoolWorkArticleViewCurrent, PoolWorkArticleView, and PoolCounterWorkViaCallback.

Referenced by execute().

error()

PoolCounterWork::error

(

$status

)

Do something with the error, like showing it to the user.

Parameters

Status

$status

Returns

mixed|false

Reimplemented in PoolWorkArticleView, and PoolCounterWorkViaCallback.

Definition at line 79 of file PoolCounterWork.php.

Referenced by execute().

execute()

PoolCounterWork::execute

(

$skipcache = false

)

Get the result of the work (whatever it is), or the result of the error() function.

This returns the result of the one of the following methods:

• doWork(): Applies if the work is exclusive or no other process is doing it, and on the condition that either this process successfully entered the pool or the pool counter is down.
• doCachedWork(): Applies if the work is cacheable and this blocked on another process which finished the work.
• fallback(): Applies for all remaining cases.

If these all return false, then the result of error() is returned.

In slow-stale mode, these three methods are called in the sequence given above, and the first non-false response is used. This means in case of concurrent cache-miss requests for the same revision, later ones will load on DBs and other backend services, and wait for earlier requests to succeed and then read out their saved result.

In fast-stale mode, if other requests hold doWork lock already, we call fallback() first to let it try to find an acceptable return value. If fallback() returns false, then we will wait for the doWork lock, as for slow stale mode, including potentially calling fallback() a second time.

Parameters

bool

$skipcache

Returns

mixed

Definition at line 132 of file PoolCounterWork.php.

References PoolCounter\DONE, doWork(), PoolCounter\ERROR, error(), fallback(), getCachedWork(), isFastStaleEnabled(), PoolCounter\LOCK_HELD, PoolCounter\LOCKED, logError(), StatusValue\newFatal(), PoolCounter\QUEUE_FULL, and PoolCounter\TIMEOUT.

Referenced by DjVuHandler\doTransform(), MediaWiki\Specials\SpecialContributions\execute(), File\getThumbnailSource(), and wfGenerateThumbnail().

fallback()

PoolCounterWork::fallback

(

$fast

)

A work not so good (eg.

expired one) but better than an error message.

Parameters

bool

$fast

True if PoolCounter is requesting a fast stale response (pre-wait)

Returns

mixed|false Work result or false

Reimplemented in PoolWorkArticleViewCurrent, and PoolCounterWorkViaCallback.

Definition at line 69 of file PoolCounterWork.php.

Referenced by execute().

getCachedWork()

PoolCounterWork::getCachedWork

(

)

Retrieve the work from cache.

Returns

mixed|false Work result or false

Reimplemented in PoolWorkArticleViewOld, PoolWorkArticleViewCurrent, and PoolCounterWorkViaCallback.

Definition at line 58 of file PoolCounterWork.php.

Referenced by execute().

isFastStaleEnabled()

PoolCounterWork::isFastStaleEnabled ( )

protected

Should fast stale mode be used?

Returns

bool

Definition at line 88 of file PoolCounterWork.php.

Referenced by execute().

logError()

PoolCounterWork::logError

(

$status

)

Log an error.

Parameters

Status

$status

Returns

void

Definition at line 98 of file PoolCounterWork.php.

References wfDebugLog().

Referenced by execute().

Member Data Documentation

$cacheable

bool PoolCounterWork::$cacheable = false

protected

Definition at line 30 of file PoolCounterWork.php.

Referenced by PoolWorkArticleViewCurrent\__construct().

$type

string PoolCounterWork::$type = 'generic'

protected

Definition at line 28 of file PoolCounterWork.php.

Referenced by PoolCounterWorkViaCallback\__construct(), and __construct().

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

• includes/poolcounter/PoolCounterWork.php