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          * @throws MWException
  43          */
  44         public function __construct( $params ) {
  45                 if ( !isset( $params['caches'] ) ) {
  46                         throw new MWException( __METHOD__ . ': the caches parameter is required' );
  47                 }
  48
  49                 $this->caches = array();
  50                 foreach ( $params['caches'] as $cacheInfo ) {
  51                         $this->caches[] = ObjectCache::newFromParams( $cacheInfo );
  52                 }
  53         }
  54
  55         /**
  56          * @param $debug bool
  57          */
  58         public function setDebug( $debug ) {
  59                 $this->doWrite( 'setDebug', $debug );
  60         }
  61
  62         /**
  63          * @param $key string
  64          * @param $casToken[optional] mixed
  65          * @return bool|mixed
  66          */
  67         public function get( $key, &$casToken = null ) {
  68                 foreach ( $this->caches as $cache ) {
  69                         $value = $cache->get( $key );
  70                         if ( $value !== false ) {
  71                                 return $value;
  72                         }
  73                 }
  74                 return false;
  75         }
  76
  77         /**
  78          * @param $casToken mixed
  79          * @param $key string
  80          * @param $value mixed
  81          * @param $exptime int
  82          * @return bool
  83          */
  84         public function cas( $casToken, $key, $value, $exptime = 0 ) {
  85                 throw new MWException( "CAS is not implemented in " . __CLASS__ );
  86         }
  87
  88         /**
  89          * @param $key string
  90          * @param $value mixed
  91          * @param $exptime int
  92          * @return bool
  93          */
  94         public function set( $key, $value, $exptime = 0 ) {
  95                 return $this->doWrite( 'set', $key, $value, $exptime );
  96         }
  97
  98         /**
  99          * @param $key string
 100          * @param $time int
 101          * @return bool
 102          */
 103         public function delete( $key, $time = 0 ) {
 104                 return $this->doWrite( 'delete', $key, $time );
 105         }
 106
 107         /**
 108          * @param $key string
 109          * @param $value mixed
 110          * @param $exptime int
 111          * @return bool
 112          */
 113         public function add( $key, $value, $exptime = 0 ) {
 114                 return $this->doWrite( 'add', $key, $value, $exptime );
 115         }
 116
 117         /**
 118          * @param $key string
 119          * @param $value mixed
 120          * @param $exptime int
 121          * @return bool
 122          */
 123         public function replace( $key, $value, $exptime = 0 ) {
 124                 return $this->doWrite( 'replace', $key, $value, $exptime );
 125         }
 126
 127         /**
 128          * @param $key string
 129          * @param $value int
 130          * @return bool|null
 131          */
 132         public function incr( $key, $value = 1 ) {
 133                 return $this->doWrite( 'incr', $key, $value );
 134         }
 135
 136         /**
 137          * @param $key string
 138          * @param $value int
 139          * @return bool
 140          */
 141         public function decr( $key, $value = 1 ) {
 142                 return $this->doWrite( 'decr', $key, $value );
 143         }
 144
 145         /**
 146          * @param $key string
 147          * @param $timeout int
 148          * @return bool
 149          */
 150         public function lock( $key, $timeout = 0 ) {
 151                 // Lock only the first cache, to avoid deadlocks
 152                 if ( isset( $this->caches[0] ) ) {
 153                         return $this->caches[0]->lock( $key, $timeout );
 154                 } else {
 155                         return true;
 156                 }
 157         }
 158
 159         /**
 160          * @param $key string
 161          * @return bool
 162          */
 163         public function unlock( $key ) {
 164                 if ( isset( $this->caches[0] ) ) {
 165                         return $this->caches[0]->unlock( $key );
 166                 } else {
 167                         return true;
 168                 }
 169         }
 170
 171         /**
 172          * @param $key string
 173          * @param $callback closure Callback method to be executed
 174          * @param int $exptime Either an interval in seconds or a unix timestamp for expiry
 175          * @param int $attempts The amount of times to attempt a merge in case of failure
 176          * @return bool success
 177          */
 178         public function merge( $key, closure $callback, $exptime = 0, $attempts = 10 ) {
 179                 return $this->doWrite( 'merge', $key, $callback, $exptime );
 180         }
 181
 182         public function getLastError() {
 183                 return isset( $this->caches[0] ) ? $this->caches[0]->getLastError() : self::ERR_NONE;
 184         }
 185
 186         public function clearLastError() {
 187                 if ( isset( $this->caches[0] ) ) {
 188                         $this->caches[0]->clearLastError();
 189                 }
 190         }
 191
 192         /**
 193          * @param $method string
 194          * @return bool
 195          */
 196         protected function doWrite( $method /*, ... */ ) {
 197                 $ret = true;
 198                 $args = func_get_args();
 199                 array_shift( $args );
 200
 201                 foreach ( $this->caches as $cache ) {
 202                         if ( !call_user_func_array( array( $cache, $method ), $args ) ) {
 203                                 $ret = false;
 204                         }
 205                 }
 206                 return $ret;
 207         }
 208
 209         /**
 210          * Delete objects expiring before a certain date.
 211          *
 212          * Succeed if any of the child caches succeed.
 213          * @param $date string
 214          * @param $progressCallback bool|callback
 215          * @return bool
 216          */
 217         public function deleteObjectsExpiringBefore( $date, $progressCallback = false ) {
 218                 $ret = false;
 219                 foreach ( $this->caches as $cache ) {
 220                         if ( $cache->deleteObjectsExpiringBefore( $date, $progressCallback ) ) {
 221                                 $ret = true;
 222                         }
 223                 }
 224                 return $ret;
 225         }
 226 }