includes/objectcache/ObjectCache.php

   1 <?php
   2 /**
   3  * Functions to get cache objects.
   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 use MediaWiki\Logger\LoggerFactory;
  25
  26 /**
  27  * Functions to get cache objects
  28  *
  29  * @ingroup Cache
  30  */
  31 class ObjectCache {
  32         /** @var Array Map of (id => BagOStuff) */
  33         public static $instances = array();
  34         /** @var Array Map of (id => WANObjectCache) */
  35         public static $wanInstances = array();
  36
  37         /**
  38          * Get a cached instance of the specified type of cache object.
  39          *
  40          * @param string $id
  41          *
  42          * @return BagOStuff
  43          */
  44         static function getInstance( $id ) {
  45                 if ( isset( self::$instances[$id] ) ) {
  46                         return self::$instances[$id];
  47                 }
  48
  49                 $object = self::newFromId( $id );
  50                 self::$instances[$id] = $object;
  51                 return $object;
  52         }
  53
  54         /**
  55          * Get a cached instance of the specified type of cache object.
  56          *
  57          * @param string $id
  58          *
  59          * @return WANObjectCache
  60          */
  61         static function getWANInstance( $id ) {
  62                 if ( isset( self::$wanInstances[$id] ) ) {
  63                         return self::$wanInstances[$id];
  64                 }
  65
  66                 $object = self::newWANCacheFromId( $id );
  67                 self::$wanInstances[$id] = $object;
  68                 return $object;
  69         }
  70
  71         /**
  72          * Clear all the cached instances.
  73          */
  74         static function clear() {
  75                 self::$instances = array();
  76                 self::$wanInstances = array();
  77         }
  78
  79         /**
  80          * Create a new cache object of the specified type.
  81          *
  82          * @param string $id
  83          *
  84          * @throws MWException
  85          * @return BagOStuff
  86          */
  87         static function newFromId( $id ) {
  88                 global $wgObjectCaches;
  89
  90                 if ( !isset( $wgObjectCaches[$id] ) ) {
  91                         throw new MWException( "Invalid object cache type \"$id\" requested. " .
  92                                 "It is not present in \$wgObjectCaches." );
  93                 }
  94
  95                 return self::newFromParams( $wgObjectCaches[$id] );
  96         }
  97
  98         /**
  99          * Create a new cache object from parameters
 100          *
 101          * @param array $params
 102          *
 103          * @throws MWException
 104          * @return BagOStuff
 105          */
 106         static function newFromParams( $params ) {
 107                 if ( isset( $params['loggroup'] ) ) {
 108                         $params['logger'] = LoggerFactory::getInstance( $params['loggroup'] );
 109                 } else {
 110                         // For backwards-compatability with custom parameters, lets not
 111                         // have all logging suddenly disappear
 112                         $params['logger'] = LoggerFactory::getInstance( 'objectcache' );
 113                 }
 114                 if ( isset( $params['factory'] ) ) {
 115                         return call_user_func( $params['factory'], $params );
 116                 } elseif ( isset( $params['class'] ) ) {
 117                         $class = $params['class'];
 118                         return new $class( $params );
 119                 } else {
 120                         throw new MWException( "The definition of cache type \""
 121                                 . print_r( $params, true ) . "\" lacks both "
 122                                 . "factory and class parameters." );
 123                 }
 124         }
 125
 126         /**
 127          * Factory function referenced from DefaultSettings.php for CACHE_ANYTHING
 128          *
 129          * CACHE_ANYTHING means that stuff has to be cached, not caching is not an option.
 130          * If a caching method is configured for any of the main caches ($wgMainCacheType,
 131          * $wgMessageCacheType, $wgParserCacheType), then CACHE_ANYTHING will effectively
 132          * be an alias to the configured cache choice for that.
 133          * If no cache choice is configured (by default $wgMainCacheType is CACHE_NONE),
 134          * then CACHE_ANYTHING will forward to CACHE_DB.
 135          * @param array $params
 136          * @return BagOStuff
 137          */
 138         static function newAnything( $params ) {
 139                 global $wgMainCacheType, $wgMessageCacheType, $wgParserCacheType;
 140                 $candidates = array( $wgMainCacheType, $wgMessageCacheType, $wgParserCacheType );
 141                 foreach ( $candidates as $candidate ) {
 142                         if ( $candidate !== CACHE_NONE && $candidate !== CACHE_ANYTHING ) {
 143                                 return self::getInstance( $candidate );
 144                         }
 145                 }
 146                 return self::getInstance( CACHE_DB );
 147         }
 148
 149         /**
 150          * Factory function referenced from DefaultSettings.php for CACHE_ACCEL.
 151          *
 152          * This will look for any APC style server-local cache.
 153          * A fallback cache can be specified if none is found.
 154          *
 155          * @param array $params
 156          * @param int|string $fallback Fallback cache, e.g. (CACHE_NONE, "hash") (since 1.24)
 157          * @throws MWException
 158          * @return BagOStuff
 159          */
 160         static function newAccelerator( $params, $fallback = null ) {
 161                 if ( function_exists( 'apc_fetch' ) ) {
 162                         $id = 'apc';
 163                 } elseif ( function_exists( 'xcache_get' ) && wfIniGetBool( 'xcache.var_size' ) ) {
 164                         $id = 'xcache';
 165                 } elseif ( function_exists( 'wincache_ucache_get' ) ) {
 166                         $id = 'wincache';
 167                 } else {
 168                         if ( $fallback !== null ) {
 169                                 return self::newFromId( $fallback );
 170                         }
 171                         throw new MWException( "CACHE_ACCEL requested but no suitable object " .
 172                                 "cache is present. You may want to install APC." );
 173                 }
 174                 return self::newFromId( $id );
 175         }
 176
 177         /**
 178          * Factory function that creates a memcached client object.
 179          *
 180          * This always uses the PHP client, since the PECL client has a different
 181          * hashing scheme and a different interpretation of the flags bitfield, so
 182          * switching between the two clients randomly would be disastrous.
 183          *
 184          * @param array $params
 185          *
 186          * @return MemcachedPhpBagOStuff
 187          */
 188         static function newMemcached( $params ) {
 189                 return new MemcachedPhpBagOStuff( $params );
 190         }
 191
 192         /**
 193          * Create a new cache object of the specified type
 194          *
 195          * @param string $id
 196          *
 197          * @throws MWException
 198          * @return WANObjectCache
 199          */
 200         static function newWANCacheFromId( $id ) {
 201                 global $wgWANObjectCaches;
 202
 203                 if ( !isset( $wgWANObjectCaches[$id] ) ) {
 204                         throw new MWException( "Invalid object cache type \"$id\" requested. " .
 205                                 "It is not present in \$wgWANObjectCaches." );
 206                 }
 207
 208                 $params = $wgWANObjectCaches[$id];
 209                 $class = $params['relayerConfig']['class'];
 210                 $params['relayer'] = new $class( $params['relayerConfig'] );
 211                 $params['cache'] = self::newFromId( $params['cacheId'] );
 212                 $class = $params['class'];
 213
 214                 return new $class( $params );
 215         }
 216 }