includes/poolcounter/PoolCounterWorkViaCallback.php

   1 <?php
   2 /**
   3  * Provides of semaphore semantics for restricting the number
   4  * of workers that may be concurrently performing the same task.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  19  * http://www.gnu.org/copyleft/gpl.html
  20  *
  21  * @file
  22  */
  23
  24 /**
  25  * Convenience class for dealing with PoolCounters using callbacks
  26  * @since 1.22
  27  */
  28 class PoolCounterWorkViaCallback extends PoolCounterWork {
  29         /** @var callable */
  30         protected $doWork;
  31         /** @var callable|null */
  32         protected $doCachedWork;
  33         /** @var callable|null */
  34         protected $fallback;
  35         /** @var callable|null */
  36         protected $error;
  37
  38         /**
  39          * Build a PoolCounterWork class from a type, key, and callback map.
  40          *
  41          * The callback map must at least have a callback for the 'doWork' method.
  42          * Additionally, callbacks can be provided for the 'doCachedWork', 'fallback',
  43          * and 'error' methods. Methods without callbacks will be no-ops that return false.
  44          * If a 'doCachedWork' callback is provided, then execute() may wait for any prior
  45          * process in the pool to finish and reuse its cached result.
  46          *
  47          * @param string $type The class of actions to limit concurrency for
  48          * @param string $key
  49          * @param array $callbacks Map of callbacks
  50          * @throws MWException
  51          */
  52         public function __construct( $type, $key, array $callbacks ) {
  53                 parent::__construct( $type, $key );
  54                 foreach ( [ 'doWork', 'doCachedWork', 'fallback', 'error' ] as $name ) {
  55                         if ( isset( $callbacks[$name] ) ) {
  56                                 if ( !is_callable( $callbacks[$name] ) ) {
  57                                         throw new MWException( "Invalid callback provided for '$name' function." );
  58                                 }
  59                                 $this->$name = $callbacks[$name];
  60                         }
  61                 }
  62                 if ( !isset( $this->doWork ) ) {
  63                         throw new MWException( "No callback provided for 'doWork' function." );
  64                 }
  65                 $this->cacheable = isset( $this->doCachedWork );
  66         }
  67
  68         public function doWork() {
  69                 return call_user_func_array( $this->doWork, [] );
  70         }
  71
  72         public function getCachedWork() {
  73                 if ( $this->doCachedWork ) {
  74                         return call_user_func_array( $this->doCachedWork, [] );
  75                 }
  76                 return false;
  77         }
  78
  79         public function fallback() {
  80                 if ( $this->fallback ) {
  81                         return call_user_func_array( $this->fallback, [] );
  82                 }
  83                 return false;
  84         }
  85
  86         public function error( $status ) {
  87                 if ( $this->error ) {
  88                         return call_user_func_array( $this->error, [ $status ] );
  89                 }
  90                 return false;
  91         }
  92 }