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 array BagOStuff[] */
  33         protected $caches;
  34
  35         /**
  36          * Constructor. Parameters are:
  37          *
  38          *   - caches:   This should have a numbered array of cache parameter
  39          *               structures, in the style required by $wgObjectCaches. See
  40          *               the documentation of $wgObjectCaches for more detail.
  41          *
  42          * @param array $params
  43          * @throws MWException
  44          */
  45         public function __construct( $params ) {
  46                 if ( !isset( $params['caches'] ) ) {
  47                         throw new MWException( __METHOD__ . ': the caches parameter is required' );
  48                 }
  49
  50                 $this->caches = array();
  51                 foreach ( $params['caches'] as $cacheInfo ) {
  52                         $this->caches[] = ObjectCache::newFromParams( $cacheInfo );
  53                 }
  54         }
  55
  56         /**
  57          * @param bool $debug
  58          */
  59         public function setDebug( $debug ) {
  60                 $this->doWrite( 'setDebug', $debug );
  61         }
  62
  63         /**
  64          * @param string $key
  65          * @param mixed $casToken [optional]
  66          * @return bool|mixed
  67          */
  68         public function get( $key, &$casToken = null ) {
  69                 foreach ( $this->caches as $cache ) {
  70                         $value = $cache->get( $key );
  71                         if ( $value !== false ) {
  72                                 return $value;
  73                         }
  74                 }
  75                 return false;
  76         }
  77
  78         /**
  79          * @param mixed $casToken
  80          * @param string $key
  81          * @param mixed $value
  82          * @param mixed $exptime
  83          * @return bool
  84          */
  85         public function cas( $casToken, $key, $value, $exptime = 0 ) {
  86                 throw new MWException( "CAS is not implemented in " . __CLASS__ );
  87         }
  88
  89         /**
  90          * @param string $key
  91          * @param mixed $value
  92          * @param int $exptime
  93          * @return bool
  94          */
  95         public function set( $key, $value, $exptime = 0 ) {
  96                 return $this->doWrite( 'set', $key, $value, $exptime );
  97         }
  98
  99         /**
 100          * @param string $key
 101          * @param int $time
 102          * @return bool
 103          */
 104         public function delete( $key, $time = 0 ) {
 105                 return $this->doWrite( 'delete', $key, $time );
 106         }
 107
 108         /**
 109          * @param string $key
 110          * @param mixed $value
 111          * @param int $exptime
 112          * @return bool
 113          */
 114         public function add( $key, $value, $exptime = 0 ) {
 115                 return $this->doWrite( 'add', $key, $value, $exptime );
 116         }
 117
 118         /**
 119          * @param string $key
 120          * @param int $value
 121          * @return bool|null
 122          */
 123         public function incr( $key, $value = 1 ) {
 124                 return $this->doWrite( 'incr', $key, $value );
 125         }
 126
 127         /**
 128          * @param string $key
 129          * @param int $value
 130          * @return bool
 131          */
 132         public function decr( $key, $value = 1 ) {
 133                 return $this->doWrite( 'decr', $key, $value );
 134         }
 135
 136         /**
 137          * @param string $key
 138          * @param int $timeout
 139          * @return bool
 140          */
 141         public function lock( $key, $timeout = 0 ) {
 142                 // Lock only the first cache, to avoid deadlocks
 143                 if ( isset( $this->caches[0] ) ) {
 144                         return $this->caches[0]->lock( $key, $timeout );
 145                 } else {
 146                         return true;
 147                 }
 148         }
 149
 150         /**
 151          * @param string $key
 152          * @return bool
 153          */
 154         public function unlock( $key ) {
 155                 if ( isset( $this->caches[0] ) ) {
 156                         return $this->caches[0]->unlock( $key );
 157                 } else {
 158                         return true;
 159                 }
 160         }
 161
 162         /**
 163          * @param string $key
 164          * @param Closure $callback Callback method to be executed
 165          * @param int $exptime Either an interval in seconds or a unix timestamp for expiry
 166          * @param int $attempts The amount of times to attempt a merge in case of failure
 167          * @return bool Success
 168          */
 169         public function merge( $key, Closure $callback, $exptime = 0, $attempts = 10 ) {
 170                 return $this->doWrite( 'merge', $key, $callback, $exptime );
 171         }
 172
 173         public function getLastError() {
 174                 return isset( $this->caches[0] ) ? $this->caches[0]->getLastError() : self::ERR_NONE;
 175         }
 176
 177         public function clearLastError() {
 178                 if ( isset( $this->caches[0] ) ) {
 179                         $this->caches[0]->clearLastError();
 180                 }
 181         }
 182
 183         /**
 184          * @param string $method
 185          * @return bool
 186          */
 187         protected function doWrite( $method /*, ... */ ) {
 188                 $ret = true;
 189                 $args = func_get_args();
 190                 array_shift( $args );
 191
 192                 foreach ( $this->caches as $cache ) {
 193                         if ( !call_user_func_array( array( $cache, $method ), $args ) ) {
 194                                 $ret = false;
 195                         }
 196                 }
 197                 return $ret;
 198         }
 199
 200         /**
 201          * Delete objects expiring before a certain date.
 202          *
 203          * Succeed if any of the child caches succeed.
 204          * @param string $date
 205          * @param bool|callable $progressCallback
 206          * @return bool
 207          */
 208         public function deleteObjectsExpiringBefore( $date, $progressCallback = false ) {
 209                 $ret = false;
 210                 foreach ( $this->caches as $cache ) {
 211                         if ( $cache->deleteObjectsExpiringBefore( $date, $progressCallback ) ) {
 212                                 $ret = true;
 213                         }
 214                 }
 215                 return $ret;
 216         }
 217 }