includes/poolcounter/PoolCounterWorkViaCallback.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  */
  20
  21 namespace MediaWiki\PoolCounter;
  22
  23 use InvalidArgumentException;
  24
  25 /**
  26  * Convenience class for dealing with PoolCounter using callbacks
  27  * @since 1.22
  28  * @newable
  29  * @note marked as newable in 1.35 for lack of a better alternative,
  30  *       but should use a factory in the future.
  31  */
  32 class PoolCounterWorkViaCallback extends PoolCounterWork {
  33         /** @var callable|null */
  34         protected $doWork;
  35         /** @var callable|null */
  36         protected $doCachedWork;
  37         /** @var callable|null */
  38         protected $fallback;
  39         /** @var callable|null */
  40         protected $error;
  41
  42         /**
  43          * Build a PoolCounterWork class from a type, key, and callback map.
  44          *
  45          * The callback map must at least have a callback for the 'doWork' method.
  46          * Additionally, callbacks can be provided for the 'doCachedWork', 'fallback',
  47          * and 'error' methods. Methods without callbacks will be no-ops that return false.
  48          * If a 'doCachedWork' callback is provided, then execute() may wait for any prior
  49          * process in the pool to finish and reuse its cached result.
  50          *
  51          * @stable to call
  52          * @param string $type The class of actions to limit concurrency for
  53          * @param string $key
  54          * @param array $callbacks Map of callbacks
  55          */
  56         public function __construct( $type, $key, array $callbacks ) {
  57                 parent::__construct( $type, $key );
  58                 foreach ( [ 'doWork', 'doCachedWork', 'fallback', 'error' ] as $name ) {
  59                         if ( isset( $callbacks[$name] ) ) {
  60                                 if ( !is_callable( $callbacks[$name] ) ) {
  61                                         throw new InvalidArgumentException( "Invalid callback provided for '$name' function." );
  62                                 }
  63                                 $this->$name = $callbacks[$name];
  64                         }
  65                 }
  66                 if ( !$this->doWork ) {
  67                         throw new InvalidArgumentException( "No callback provided for 'doWork' function." );
  68                 }
  69                 $this->cacheable = (bool)$this->doCachedWork;
  70         }
  71
  72         public function doWork() {
  73                 return ( $this->doWork )();
  74         }
  75
  76         public function getCachedWork() {
  77                 if ( $this->doCachedWork ) {
  78                         return ( $this->doCachedWork )();
  79                 }
  80                 return false;
  81         }
  82
  83         public function fallback( $fast ) {
  84                 if ( $this->fallback ) {
  85                         return ( $this->fallback )( $fast );
  86                 }
  87                 return false;
  88         }
  89
  90         public function error( $status ) {
  91                 if ( $this->error ) {
  92                         return ( $this->error )( $status );
  93                 }
  94                 return false;
  95         }
  96 }
  97
  98 /** @deprecated class alias since 1.42 */
  99 class_alias( PoolCounterWorkViaCallback::class, 'PoolCounterWorkViaCallback' );