Merge "Set autofocus on Special:Unblock"

[lhc/web/wiklou.git] / includes / poolcounter / PoolCounter.php

diff --git a/includes/poolcounter/PoolCounter.php b/includes/poolcounter/PoolCounter.php
index 34953c0..f8d48cc 100644 (file)
--- a/includes/poolcounter/PoolCounter.php
+++ b/includes/poolcounter/PoolCounter.php
@@ -53,8 +53,15 @@ abstract class PoolCounter {
 
        /** @var string All workers with the same key share the lock */
        protected $key;
-       /** @var int Maximum number of workers doing the task simultaneously */
+       /** @var int Maximum number of workers working on tasks with the same key simultaneously */
        protected $workers;
+       /**
+        * Maximum number of workers working on this task type, regardless of key.
+        * 0 means unlimited. Max allowed value is 65536.
+        * The way the slot limit is enforced is overzealous - this option should be used with caution.
+        * @var int
+        */
+       protected $slots = 0;
        /** @var int If this number of workers are already working/waiting, fail instead of wait */
        protected $maxqueue;
        /** @var float Maximum time in seconds to wait for the lock */
@@ -66,10 +73,17 @@ abstract class PoolCounter {
         * @param string $key
         */
        protected function __construct( $conf, $type, $key ) {
-               $this->key = $key;
                $this->workers = $conf['workers'];
                $this->maxqueue = $conf['maxqueue'];
                $this->timeout = $conf['timeout'];
+               if ( isset( $conf['slots'] ) ) {
+                       $this->slots = $conf['slots'];
+               }
+
+               if ( $this->slots ) {
+                       $key = $this->hashKeyIntoSlots( $key, $this->slots );
+               }
+               $this->key = $key;
        }
 
        /**
@@ -121,6 +135,20 @@ abstract class PoolCounter {
         * @return Status value is one of Released/NotLocked/Error
         */
        abstract public function release();
+
+       /**
+        * Given a key (any string) and the number of lots, returns a slot number (an integer from the [0..($slots-1)] range).
+        * This is used for a global limit on the number of instances  of a given type that can acquire a lock.
+        * The hashing is deterministic so that PoolCounter::$workers is always an upper limit of how many instances with
+        * the same key can acquire a lock.
+        *
+        * @param string $key PoolCounter instance key (any string)
+        * @param int $slots the number of slots (max allowed value is 65536)
+        * @return int
+        */
+       protected function hashKeyIntoSlots( $key, $slots ) {
+               return hexdec( substr( sha1( $key ), 0, 4 ) ) % $slots;
+       }
 }
 
 // @codingStandardsIgnoreStart Squiz.Classes.ValidClassName.NotCamelCaps