includes/libs/objectcache/CachedBagOStuff.php

   1 <?php
   2 /**
   3  * Wrapper around a BagOStuff that caches data in memory
   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  * Wrapper around a BagOStuff that caches data in memory
  26  *
  27  * The differences between CachedBagOStuff and MultiWriteBagOStuff are:
  28  * * CachedBagOStuff supports only one "backend".
  29  * * There's a flag for writes to only go to the in-memory cache.
  30  * * The in-memory cache is always updated.
  31  * * Locks go to the backend cache (with MultiWriteBagOStuff, it would wind
  32  *   up going to the HashBagOStuff used for the in-memory cache).
  33  *
  34  * @ingroup Cache
  35  */
  36 class CachedBagOStuff extends BagOStuff {
  37         /** @var BagOStuff */
  38         protected $backend;
  39         /** @var HashBagOStuff */
  40         protected $procCache;
  41
  42         /**
  43          * @param BagOStuff $backend Permanent backend to use
  44          * @param array $params Parameters for HashBagOStuff
  45          */
  46         public function __construct( BagOStuff $backend, $params = [] ) {
  47                 unset( $params['reportDupes'] ); // useless here
  48
  49                 parent::__construct( $params );
  50
  51                 $this->backend = $backend;
  52                 $this->procCache = new HashBagOStuff( $params );
  53                 $this->attrMap = $backend->attrMap;
  54         }
  55
  56         protected function doGet( $key, $flags = 0, &$casToken = null ) {
  57                 $ret = $this->procCache->get( $key, $flags );
  58                 if ( $ret === false && !$this->procCache->hasKey( $key ) ) {
  59                         $ret = $this->backend->get( $key, $flags );
  60                         $this->set( $key, $ret, self::TTL_INDEFINITE, self::WRITE_CACHE_ONLY );
  61                 }
  62
  63                 return $ret;
  64         }
  65
  66         protected function doSet( $key, $value, $exptime = 0, $flags = 0 ) {
  67                 $this->procCache->set( $key, $value, $exptime, $flags );
  68                 if ( ( $flags & self::WRITE_CACHE_ONLY ) != self::WRITE_CACHE_ONLY ) {
  69                         $this->backend->set( $key, $value, $exptime, $flags );
  70                 }
  71
  72                 return true;
  73         }
  74
  75         protected function doDelete( $key, $flags = 0 ) {
  76                 $this->procCache->delete( $key, $flags );
  77                 if ( ( $flags & self::WRITE_CACHE_ONLY ) != self::WRITE_CACHE_ONLY ) {
  78                         $this->backend->delete( $key, $flags );
  79                 }
  80
  81                 return true;
  82         }
  83
  84         public function deleteObjectsExpiringBefore(
  85                 $timestamp,
  86                 callable $progress = null,
  87                 $limit = INF
  88         ) {
  89                 $this->procCache->deleteObjectsExpiringBefore( $timestamp, $progress, $limit );
  90
  91                 return $this->backend->deleteObjectsExpiringBefore( $timestamp, $progress, $limit );
  92         }
  93
  94         // These just call the backend (tested elsewhere)
  95         // @codeCoverageIgnoreStart
  96
  97         public function add( $key, $value, $exptime = 0, $flags = 0 ) {
  98                 if ( $this->get( $key ) === false ) {
  99                         return $this->set( $key, $value, $exptime, $flags );
 100                 }
 101
 102                 return false; // key already set
 103         }
 104
 105         public function incr( $key, $value = 1 ) {
 106                 $n = $this->backend->incr( $key, $value );
 107
 108                 $this->procCache->delete( $key );
 109
 110                 return $n;
 111         }
 112
 113         public function lock( $key, $timeout = 6, $expiry = 6, $rclass = '' ) {
 114                 return $this->backend->lock( $key, $timeout, $expiry, $rclass );
 115         }
 116
 117         public function unlock( $key ) {
 118                 return $this->backend->unlock( $key );
 119         }
 120
 121         public function makeKeyInternal( $keyspace, $args ) {
 122                 return $this->backend->makeKeyInternal( ...func_get_args() );
 123         }
 124
 125         public function makeKey( $class, $component = null ) {
 126                 return $this->backend->makeKey( ...func_get_args() );
 127         }
 128
 129         public function makeGlobalKey( $class, $component = null ) {
 130                 return $this->backend->makeGlobalKey( ...func_get_args() );
 131         }
 132
 133         public function setDebug( $bool ) {
 134                 parent::setDebug( $bool );
 135                 $this->backend->setDebug( $bool );
 136         }
 137
 138         public function getLastError() {
 139                 return $this->backend->getLastError();
 140         }
 141
 142         public function clearLastError() {
 143                 return $this->backend->clearLastError();
 144         }
 145
 146         // @codeCoverageIgnoreEnd
 147 }