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                 parent::__construct( $params );
  47                 if ( !isset( $params['caches'] ) ) {
  48                         throw new MWException( __METHOD__ . ': the caches parameter is required' );
  49                 }
  50
  51                 $this->caches = array();
  52                 foreach ( $params['caches'] as $cacheInfo ) {
  53                         $this->caches[] = ObjectCache::newFromParams( $cacheInfo );
  54                 }
  55         }
  56
  57         /**
  58          * @param bool $debug
  59          */
  60         public function setDebug( $debug ) {
  61                 $this->doWrite( 'setDebug', $debug );
  62         }
  63
  64         /**
  65          * @param string $key
  66          * @param mixed $casToken [optional]
  67          * @return bool|mixed
  68          */
  69         public function get( $key, &$casToken = null ) {
  70                 foreach ( $this->caches as $cache ) {
  71                         $value = $cache->get( $key );
  72                         if ( $value !== false ) {
  73                                 return $value;
  74                         }
  75                 }
  76                 return false;
  77         }
  78
  79         /**
  80          * @param mixed $casToken
  81          * @param string $key
  82          * @param mixed $value
  83          * @param mixed $exptime
  84          * @return bool
  85          * @throws MWException
  86          */
  87         protected function cas( $casToken, $key, $value, $exptime = 0 ) {
  88                 throw new MWException( "CAS is not implemented in " . __CLASS__ );
  89         }
  90
  91         /**
  92          * @param string $key
  93          * @param mixed $value
  94          * @param int $exptime
  95          * @return bool
  96          */
  97         public function set( $key, $value, $exptime = 0 ) {
  98                 return $this->doWrite( 'set', $key, $value, $exptime );
  99         }
 100
 101         /**
 102          * @param string $key
 103          * @return bool
 104          */
 105         public function delete( $key ) {
 106                 return $this->doWrite( 'delete', $key );
 107         }
 108
 109         /**
 110          * @param string $key
 111          * @param mixed $value
 112          * @param int $exptime
 113          * @return bool
 114          */
 115         public function add( $key, $value, $exptime = 0 ) {
 116                 return $this->doWrite( 'add', $key, $value, $exptime );
 117         }
 118
 119         /**
 120          * @param string $key
 121          * @param int $value
 122          * @return bool|null
 123          */
 124         public function incr( $key, $value = 1 ) {
 125                 return $this->doWrite( 'incr', $key, $value );
 126         }
 127
 128         /**
 129          * @param string $key
 130          * @param int $value
 131          * @return bool
 132          */
 133         public function decr( $key, $value = 1 ) {
 134                 return $this->doWrite( 'decr', $key, $value );
 135         }
 136
 137         /**
 138          * @param string $key
 139          * @param int $timeout
 140          * @param int $expiry
 141          * @return bool
 142          */
 143         public function lock( $key, $timeout = 6, $expiry = 6 ) {
 144                 // Lock only the first cache, to avoid deadlocks
 145                 if ( isset( $this->caches[0] ) ) {
 146                         return $this->caches[0]->lock( $key, $timeout, $expiry );
 147                 } else {
 148                         return true;
 149                 }
 150         }
 151
 152         /**
 153          * @param string $key
 154          * @return bool
 155          */
 156         public function unlock( $key ) {
 157                 if ( isset( $this->caches[0] ) ) {
 158                         return $this->caches[0]->unlock( $key );
 159                 } else {
 160                         return true;
 161                 }
 162         }
 163
 164         /**
 165          * @param string $key
 166          * @param callable $callback Callback method to be executed
 167          * @param int $exptime Either an interval in seconds or a unix timestamp for expiry
 168          * @param int $attempts The amount of times to attempt a merge in case of failure
 169          * @return bool Success
 170          */
 171         public function merge( $key, $callback, $exptime = 0, $attempts = 10 ) {
 172                 return $this->doWrite( 'merge', $key, $callback, $exptime );
 173         }
 174
 175         public function getLastError() {
 176                 return isset( $this->caches[0] ) ? $this->caches[0]->getLastError() : self::ERR_NONE;
 177         }
 178
 179         public function clearLastError() {
 180                 if ( isset( $this->caches[0] ) ) {
 181                         $this->caches[0]->clearLastError();
 182                 }
 183         }
 184
 185         /**
 186          * @param string $method
 187          * @return bool
 188          */
 189         protected function doWrite( $method /*, ... */ ) {
 190                 $ret = true;
 191                 $args = func_get_args();
 192                 array_shift( $args );
 193
 194                 foreach ( $this->caches as $cache ) {
 195                         if ( !call_user_func_array( array( $cache, $method ), $args ) ) {
 196                                 $ret = false;
 197                         }
 198                 }
 199                 return $ret;
 200         }
 201
 202         /**
 203          * Delete objects expiring before a certain date.
 204          *
 205          * Succeed if any of the child caches succeed.
 206          * @param string $date
 207          * @param bool|callable $progressCallback
 208          * @return bool
 209          */
 210         public function deleteObjectsExpiringBefore( $date, $progressCallback = false ) {
 211                 $ret = false;
 212                 foreach ( $this->caches as $cache ) {
 213                         if ( $cache->deleteObjectsExpiringBefore( $date, $progressCallback ) ) {
 214                                 $ret = true;
 215                         }
 216                 }
 217                 return $ret;
 218         }
 219 }