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          * @since 1.26
  61          */
  62         static function getWANInstance( $id ) {
  63                 if ( isset( self::$wanInstances[$id] ) ) {
  64                         return self::$wanInstances[$id];
  65                 }
  66
  67                 $object = self::newWANCacheFromId( $id );
  68                 self::$wanInstances[$id] = $object;
  69                 return $object;
  70         }
  71
  72         /**
  73          * Clear all the cached instances.
  74          */
  75         static function clear() {
  76                 self::$instances = array();
  77                 self::$wanInstances = array();
  78         }
  79
  80         /**
  81          * Create a new cache object of the specified type.
  82          *
  83          * @param string $id
  84          *
  85          * @throws MWException
  86          * @return BagOStuff
  87          */
  88         static function newFromId( $id ) {
  89                 global $wgObjectCaches;
  90
  91                 if ( !isset( $wgObjectCaches[$id] ) ) {
  92                         throw new MWException( "Invalid object cache type \"$id\" requested. " .
  93                                 "It is not present in \$wgObjectCaches." );
  94                 }
  95
  96                 return self::newFromParams( $wgObjectCaches[$id] );
  97         }
  98
  99         /**
 100          * Create a new cache object from parameters
 101          *
 102          * @param array $params
 103          *
 104          * @throws MWException
 105          * @return BagOStuff
 106          */
 107         static function newFromParams( $params ) {
 108                 if ( isset( $params['loggroup'] ) ) {
 109                         $params['logger'] = LoggerFactory::getInstance( $params['loggroup'] );
 110                 } else {
 111                         // For backwards-compatability with custom parameters, lets not
 112                         // have all logging suddenly disappear
 113                         $params['logger'] = LoggerFactory::getInstance( 'objectcache' );
 114                 }
 115                 if ( isset( $params['factory'] ) ) {
 116                         return call_user_func( $params['factory'], $params );
 117                 } elseif ( isset( $params['class'] ) ) {
 118                         $class = $params['class'];
 119                         return new $class( $params );
 120                 } else {
 121                         throw new MWException( "The definition of cache type \""
 122                                 . print_r( $params, true ) . "\" lacks both "
 123                                 . "factory and class parameters." );
 124                 }
 125         }
 126
 127         /**
 128          * Factory function referenced from DefaultSettings.php for CACHE_ANYTHING
 129          *
 130          * CACHE_ANYTHING means that stuff has to be cached, not caching is not an option.
 131          * If a caching method is configured for any of the main caches ($wgMainCacheType,
 132          * $wgMessageCacheType, $wgParserCacheType), then CACHE_ANYTHING will effectively
 133          * be an alias to the configured cache choice for that.
 134          * If no cache choice is configured (by default $wgMainCacheType is CACHE_NONE),
 135          * then CACHE_ANYTHING will forward to CACHE_DB.
 136          * @param array $params
 137          * @return BagOStuff
 138          */
 139         static function newAnything( $params ) {
 140                 global $wgMainCacheType, $wgMessageCacheType, $wgParserCacheType;
 141                 $candidates = array( $wgMainCacheType, $wgMessageCacheType, $wgParserCacheType );
 142                 foreach ( $candidates as $candidate ) {
 143                         if ( $candidate !== CACHE_NONE && $candidate !== CACHE_ANYTHING ) {
 144                                 return self::getInstance( $candidate );
 145                         }
 146                 }
 147                 return self::getInstance( CACHE_DB );
 148         }
 149
 150         /**
 151          * Factory function referenced from DefaultSettings.php for CACHE_ACCEL.
 152          *
 153          * This will look for any APC style server-local cache.
 154          * A fallback cache can be specified if none is found.
 155          *
 156          * @param array $params
 157          * @param int|string $fallback Fallback cache, e.g. (CACHE_NONE, "hash") (since 1.24)
 158          * @throws MWException
 159          * @return BagOStuff
 160          */
 161         static function newAccelerator( $params, $fallback = null ) {
 162                 if ( function_exists( 'apc_fetch' ) ) {
 163                         $id = 'apc';
 164                 } elseif ( function_exists( 'xcache_get' ) && wfIniGetBool( 'xcache.var_size' ) ) {
 165                         $id = 'xcache';
 166                 } elseif ( function_exists( 'wincache_ucache_get' ) ) {
 167                         $id = 'wincache';
 168                 } else {
 169                         if ( $fallback !== null ) {
 170                                 return self::newFromId( $fallback );
 171                         }
 172                         throw new MWException( "CACHE_ACCEL requested but no suitable object " .
 173                                 "cache is present. You may want to install APC." );
 174                 }
 175                 return self::newFromId( $id );
 176         }
 177
 178         /**
 179          * Factory function that creates a memcached client object.
 180          *
 181          * This always uses the PHP client, since the PECL client has a different
 182          * hashing scheme and a different interpretation of the flags bitfield, so
 183          * switching between the two clients randomly would be disastrous.
 184          *
 185          * @param array $params
 186          *
 187          * @return MemcachedPhpBagOStuff
 188          */
 189         static function newMemcached( $params ) {
 190                 return new MemcachedPhpBagOStuff( $params );
 191         }
 192
 193         /**
 194          * Create a new cache object of the specified type
 195          *
 196          * @param string $id
 197          *
 198          * @throws MWException
 199          * @return WANObjectCache
 200          * @since 1.26
 201          */
 202         static function newWANCacheFromId( $id ) {
 203                 global $wgWANObjectCaches;
 204
 205                 if ( !isset( $wgWANObjectCaches[$id] ) ) {
 206                         throw new MWException( "Invalid object cache type \"$id\" requested. " .
 207                                 "It is not present in \$wgWANObjectCaches." );
 208                 }
 209
 210                 $params = $wgWANObjectCaches[$id];
 211                 $class = $params['relayerConfig']['class'];
 212                 $params['relayer'] = new $class( $params['relayerConfig'] );
 213                 $params['cache'] = self::newFromId( $params['cacheId'] );
 214                 $class = $params['class'];
 215
 216                 return new $class( $params );
 217         }
 218
 219         /**
 220          * Get the main WAN cache object
 221          *
 222          * @return WANObjectCache
 223          * @since 1.26
 224          */
 225         static function getMainWANInstance() {
 226                 global $wgMainWANCache;
 227
 228                 return self::getWANInstance( $wgMainWANCache );
 229         }
 230 }