MediaWiki  REL1_31
PoolCounter.php
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1 <?php
45 abstract class PoolCounter {
46  /* Return codes */
47  const LOCKED = 1; /* Lock acquired */
48  const RELEASED = 2; /* Lock released */
49  const DONE = 3; /* Another worker did the work for you */
50 
51  const ERROR = -1; /* Indeterminate error */
52  const NOT_LOCKED = -2; /* Called release() with no lock held */
53  const QUEUE_FULL = -3; /* There are already maxqueue workers on this lock */
54  const TIMEOUT = -4; /* Timeout exceeded */
55  const LOCK_HELD = -5; /* Cannot acquire another lock while you have one lock held */
56 
58  protected $key;
60  protected $workers;
67  protected $slots = 0;
69  protected $maxqueue;
71  protected $timeout;
72 
76  private $isMightWaitKey;
80  private static $acquiredMightWaitKey = 0;
81 
87  protected function __construct( $conf, $type, $key ) {
88  $this->workers = $conf['workers'];
89  $this->maxqueue = $conf['maxqueue'];
90  $this->timeout = $conf['timeout'];
91  if ( isset( $conf['slots'] ) ) {
92  $this->slots = $conf['slots'];
93  }
94 
95  if ( $this->slots ) {
96  $key = $this->hashKeyIntoSlots( $type, $key, $this->slots );
97  }
98 
99  $this->key = $key;
100  $this->isMightWaitKey = !preg_match( '/^nowait:/', $this->key );
101  }
102 
111  public static function factory( $type, $key ) {
113  if ( !isset( $wgPoolCounterConf[$type] ) ) {
114  return new PoolCounter_Stub;
115  }
116  $conf = $wgPoolCounterConf[$type];
117  $class = $conf['class'];
118 
119  return new $class( $conf, $type, $key );
120  }
121 
125  public function getKey() {
126  return $this->key;
127  }
128 
134  abstract public function acquireForMe();
135 
142  abstract public function acquireForAnyone();
143 
151  abstract public function release();
152 
158  final protected function precheckAcquire() {
159  if ( $this->isMightWaitKey ) {
160  if ( self::$acquiredMightWaitKey ) {
161  /*
162  * The poolcounter itself is quite happy to allow you to wait
163  * on another lock while you have a lock you waited on already
164  * but we think that it is unlikely to be a good idea. So we
165  * made it an error. If you are _really_ _really_ sure it is a
166  * good idea then feel free to implement an unsafe flag or
167  * something.
168  */
169  return Status::newFatal( 'poolcounter-usage-error',
170  'You may only aquire a single non-nowait lock.' );
171  }
172  } elseif ( $this->timeout !== 0 ) {
173  return Status::newFatal( 'poolcounter-usage-error',
174  'Locks starting in nowait: must have 0 timeout.' );
175  }
176  return Status::newGood();
177  }
178 
183  final protected function onAcquire() {
184  self::$acquiredMightWaitKey |= $this->isMightWaitKey;
185  }
186 
191  final protected function onRelease() {
192  self::$acquiredMightWaitKey &= !$this->isMightWaitKey;
193  }
194 
207  protected function hashKeyIntoSlots( $type, $key, $slots ) {
208  return $type . ':' . ( hexdec( substr( sha1( $key ), 0, 4 ) ) % $slots );
209  }
210 }
211 
212 // phpcs:ignore Squiz.Classes.ValidClassName.NotCamelCaps
214 
215  public function __construct() {
216  /* No parameters needed */
217  }
218 
219  public function acquireForMe() {
221  }
222 
223  public function acquireForAnyone() {
225  }
226 
227  public function release() {
229  }
230 }
PoolCounter_Stub\release
release()
I have successfully finished my task.
Definition: PoolCounter.php:227
PoolCounter\onAcquire
onAcquire()
Update any lock tracking information when the lock is acquired.
Definition: PoolCounter.php:183
PoolCounter\LOCK_HELD
const LOCK_HELD
Definition: PoolCounter.php:55
PoolCounter_Stub\acquireForAnyone
acquireForAnyone()
I want to do this task, but if anyone else does it instead, it's also fine for me.
Definition: PoolCounter.php:223
PoolCounter\NOT_LOCKED
const NOT_LOCKED
Definition: PoolCounter.php:52
PoolCounter\acquireForMe
acquireForMe()
I want to do this task and I need to do it myself.
StatusValue\newFatal
static newFatal( $message)
Factory function for fatal errors.
Definition: StatusValue.php:68
PoolCounter\LOCKED
const LOCKED
Definition: PoolCounter.php:47
PoolCounter\release
release()
I have successfully finished my task.
PoolCounter\$workers
int $workers
Maximum number of workers working on tasks with the same key simultaneously.
Definition: PoolCounter.php:60
PoolCounter\onRelease
onRelease()
Update any lock tracking information when the lock is released.
Definition: PoolCounter.php:191
PoolCounter\$acquiredMightWaitKey
static bool $acquiredMightWaitKey
Whether this process holds a "might wait" lock key.
Definition: PoolCounter.php:80
PoolCounter\acquireForAnyone
acquireForAnyone()
I want to do this task, but if anyone else does it instead, it's also fine for me.
php
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition: injection.txt:37
PoolCounter
When you have many workers (threads/servers) giving service, and a cached item expensive to produce e...
Definition: PoolCounter.php:45
key
design txt This is a brief overview of the new design More thorough and up to date information is available on the documentation wiki at etc Handles the details of getting and saving to the user table of the and dealing with sessions and cookies OutputPage Encapsulates the entire HTML page that will be sent in response to any server request It is used by calling its functions to add in any and then calling but I prefer the flexibility This should also do the output encoding The system allocates a global one in $wgOut Title Represents the title of an and does all the work of translating among various forms such as plain database key
Definition: design.txt:26
PoolCounter\$isMightWaitKey
bool $isMightWaitKey
Whether the key is a "might wait" key.
Definition: PoolCounter.php:76
PoolCounter\$maxqueue
int $maxqueue
If this number of workers are already working/waiting, fail instead of wait.
Definition: PoolCounter.php:69
PoolCounter\__construct
__construct( $conf, $type, $key)
Definition: PoolCounter.php:87
global
when a variable name is used in a it is silently declared as a new masking the global
Definition: design.txt:95
PoolCounter\$key
string $key
All workers with the same key share the lock.
Definition: PoolCounter.php:58
PoolCounter\QUEUE_FULL
const QUEUE_FULL
Definition: PoolCounter.php:53
StatusValue\newGood
static newGood( $value=null)
Factory function for good results.
Definition: StatusValue.php:81
PoolCounter\ERROR
const ERROR
Definition: PoolCounter.php:51
PoolCounter\factory
static factory( $type, $key)
Create a Pool counter.
Definition: PoolCounter.php:111
PoolCounter\$slots
int $slots
Maximum number of workers working on this task type, regardless of key.
Definition: PoolCounter.php:67
PoolCounter\getKey
getKey()
Definition: PoolCounter.php:125
PoolCounter_Stub
Definition: PoolCounter.php:213
$wgPoolCounterConf
$wgPoolCounterConf
Configuration for processing pool control, for use in high-traffic wikis.
Definition: DefaultSettings.php:8539
PoolCounter\$timeout
float $timeout
Maximum time in seconds to wait for the lock.
Definition: PoolCounter.php:71
PoolCounter\hashKeyIntoSlots
hashKeyIntoSlots( $type, $key, $slots)
Given a key (any string) and the number of lots, returns a slot key (a prefix with a suffix integer f...
Definition: PoolCounter.php:207
PoolCounter_Stub\acquireForMe
acquireForMe()
I want to do this task and I need to do it myself.
Definition: PoolCounter.php:219
PoolCounter\RELEASED
const RELEASED
Definition: PoolCounter.php:48
PoolCounter\TIMEOUT
const TIMEOUT
Definition: PoolCounter.php:54
PoolCounter\precheckAcquire
precheckAcquire()
Checks that the lock request is sane.
Definition: PoolCounter.php:158
PoolCounter\DONE
const DONE
Definition: PoolCounter.php:49
PoolCounter_Stub\__construct
__construct()
Definition: PoolCounter.php:215
$type
$type
Definition: testCompression.php:48