includes/objectcache/MultiWriteBagOStuff.php

   1 <?php
   2 /**
   3  * Wrapper for object caching in different caches.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Cache
  22  */
  23
  24 /**
  25  * A cache class that replicates all writes to multiple child caches. Reads
  26  * are implemented by reading from the caches in the order they are given in
  27  * the configuration until a cache gives a positive result.
  28  *
  29  * @ingroup Cache
  30  */
  31 class MultiWriteBagOStuff extends BagOStuff {
  32         var $caches;
  33
  34         /**
  35          * Constructor. Parameters are:
  36          *
  37          *   - caches:   This should have a numbered array of cache parameter
  38          *               structures, in the style required by $wgObjectCaches. See
  39          *               the documentation of $wgObjectCaches for more detail.
  40          *
  41          * @param $params array
  42          */
  43         public function __construct( $params ) {
  44                 if ( !isset( $params['caches'] ) ) {
  45                         throw new MWException( __METHOD__.': the caches parameter is required' );
  46                 }
  47
  48                 $this->caches = array();
  49                 foreach ( $params['caches'] as $cacheInfo ) {
  50                         $this->caches[] = ObjectCache::newFromParams( $cacheInfo );
  51                 }
  52         }
  53
  54         public function setDebug( $debug ) {
  55                 $this->doWrite( 'setDebug', $debug );
  56         }
  57
  58         public function get( $key ) {
  59                 foreach ( $this->caches as $cache ) {
  60                         $value = $cache->get( $key );
  61                         if ( $value !== false ) {
  62                                 return $value;
  63                         }
  64                 }
  65                 return false;
  66         }
  67
  68         public function set( $key, $value, $exptime = 0 ) {
  69                 return $this->doWrite( 'set', $key, $value, $exptime );
  70         }
  71
  72         public function delete( $key, $time = 0 ) {
  73                 return $this->doWrite( 'delete', $key, $time );
  74         }
  75
  76         public function add( $key, $value, $exptime = 0 ) {
  77                 return $this->doWrite( 'add', $key, $value, $exptime );
  78         }
  79
  80         public function replace( $key, $value, $exptime = 0 ) {
  81                 return $this->doWrite( 'replace', $key, $value, $exptime );
  82         }
  83
  84         public function incr( $key, $value = 1 ) {
  85                 return $this->doWrite( 'incr', $key, $value );
  86         }
  87
  88         public function decr( $key, $value = 1 ) {
  89                 return $this->doWrite( 'decr', $key, $value );
  90         }
  91
  92         public function lock( $key, $timeout = 0 ) {
  93                 // Lock only the first cache, to avoid deadlocks
  94                 if ( isset( $this->caches[0] ) ) {
  95                         return $this->caches[0]->lock( $key, $timeout );
  96                 } else {
  97                         return true;
  98                 }
  99         }
 100
 101         public function unlock( $key ) {
 102                 if ( isset( $this->caches[0] ) ) {
 103                         return $this->caches[0]->unlock( $key );
 104                 } else {
 105                         return true;
 106                 }
 107         }
 108
 109         protected function doWrite( $method /*, ... */ ) {
 110                 $ret = true;
 111                 $args = func_get_args();
 112                 array_shift( $args );
 113
 114                 foreach ( $this->caches as $cache ) {
 115                         if ( !call_user_func_array( array( $cache, $method ), $args ) ) {
 116                                 $ret = false;
 117                         }
 118                 }
 119                 return $ret;
 120         }
 121
 122         /**
 123          * Delete objects expiring before a certain date.
 124          *
 125          * Succeed if any of the child caches succeed.
 126          * @return bool
 127          */
 128         public function deleteObjectsExpiringBefore( $date, $progressCallback = false ) {
 129                 $ret = false;
 130                 foreach ( $this->caches as $cache ) {
 131                         if ( $cache->deleteObjectsExpiringBefore( $date, $progressCallback ) ) {
 132                                 $ret = true;
 133                         }
 134                 }
 135                 return $ret;
 136         }
 137 }