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 InvalidArgumentException
  44          */
  45         public function __construct( $params ) {
  46                 parent::__construct( $params );
  47                 if ( !isset( $params['caches'] ) ) {
  48                         throw new InvalidArgumentException( __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         public function get( $key, &$casToken = null, $flags = 0 ) {
  65                 foreach ( $this->caches as $cache ) {
  66                         $value = $cache->get( $key, null, $flags = 0 );
  67                         if ( $value !== false ) {
  68                                 return $value;
  69                         }
  70                 }
  71                 return false;
  72         }
  73
  74         /**
  75          * @param string $key
  76          * @param mixed $value
  77          * @param int $exptime
  78          * @return bool
  79          */
  80         public function set( $key, $value, $exptime = 0 ) {
  81                 return $this->doWrite( 'set', $key, $value, $exptime );
  82         }
  83
  84         /**
  85          * @param string $key
  86          * @return bool
  87          */
  88         public function delete( $key ) {
  89                 return $this->doWrite( 'delete', $key );
  90         }
  91
  92         /**
  93          * @param string $key
  94          * @param mixed $value
  95          * @param int $exptime
  96          * @return bool
  97          */
  98         public function add( $key, $value, $exptime = 0 ) {
  99                 return $this->doWrite( 'add', $key, $value, $exptime );
 100         }
 101
 102         /**
 103          * @param string $key
 104          * @param int $value
 105          * @return bool|null
 106          */
 107         public function incr( $key, $value = 1 ) {
 108                 return $this->doWrite( 'incr', $key, $value );
 109         }
 110
 111         /**
 112          * @param string $key
 113          * @param int $value
 114          * @return bool
 115          */
 116         public function decr( $key, $value = 1 ) {
 117                 return $this->doWrite( 'decr', $key, $value );
 118         }
 119
 120         /**
 121          * @param string $key
 122          * @param int $timeout
 123          * @param int $expiry
 124          * @return bool
 125          */
 126         public function lock( $key, $timeout = 6, $expiry = 6 ) {
 127                 // Lock only the first cache, to avoid deadlocks
 128                 if ( isset( $this->caches[0] ) ) {
 129                         return $this->caches[0]->lock( $key, $timeout, $expiry );
 130                 } else {
 131                         return true;
 132                 }
 133         }
 134
 135         /**
 136          * @param string $key
 137          * @return bool
 138          */
 139         public function unlock( $key ) {
 140                 if ( isset( $this->caches[0] ) ) {
 141                         return $this->caches[0]->unlock( $key );
 142                 } else {
 143                         return true;
 144                 }
 145         }
 146
 147         /**
 148          * @param string $key
 149          * @param callable $callback Callback method to be executed
 150          * @param int $exptime Either an interval in seconds or a unix timestamp for expiry
 151          * @param int $attempts The amount of times to attempt a merge in case of failure
 152          * @return bool Success
 153          */
 154         public function merge( $key, $callback, $exptime = 0, $attempts = 10 ) {
 155                 return $this->doWrite( 'merge', $key, $callback, $exptime );
 156         }
 157
 158         public function getLastError() {
 159                 return isset( $this->caches[0] ) ? $this->caches[0]->getLastError() : self::ERR_NONE;
 160         }
 161
 162         public function clearLastError() {
 163                 if ( isset( $this->caches[0] ) ) {
 164                         $this->caches[0]->clearLastError();
 165                 }
 166         }
 167
 168         /**
 169          * @param string $method
 170          * @return bool
 171          */
 172         protected function doWrite( $method /*, ... */ ) {
 173                 $ret = true;
 174                 $args = func_get_args();
 175                 array_shift( $args );
 176
 177                 foreach ( $this->caches as $cache ) {
 178                         if ( !call_user_func_array( array( $cache, $method ), $args ) ) {
 179                                 $ret = false;
 180                         }
 181                 }
 182                 return $ret;
 183         }
 184
 185         /**
 186          * Delete objects expiring before a certain date.
 187          *
 188          * Succeed if any of the child caches succeed.
 189          * @param string $date
 190          * @param bool|callable $progressCallback
 191          * @return bool
 192          */
 193         public function deleteObjectsExpiringBefore( $date, $progressCallback = false ) {
 194                 $ret = false;
 195                 foreach ( $this->caches as $cache ) {
 196                         if ( $cache->deleteObjectsExpiringBefore( $date, $progressCallback ) ) {
 197                                 $ret = true;
 198                         }
 199                 }
 200                 return $ret;
 201         }
 202 }