includes/objectcache/ObjectCache.php

   1 <?php
   2 /**
   3  * Functions to get cache objects
   4  *
   5  * @file
   6  * @ingroup Cache
   7  */
   8 class ObjectCache {
   9         static $instances = array();
  10
  11         /**
  12          * Get a cached instance of the specified type of cache object.
  13          *
  14          * @param $id
  15          *
  16          * @return object
  17          */
  18         static function getInstance( $id ) {
  19                 if ( isset( self::$instances[$id] ) ) {
  20                         return self::$instances[$id];
  21                 }
  22
  23                 $object = self::newFromId( $id );
  24                 self::$instances[$id] = $object;
  25                 return $object;
  26         }
  27
  28         /**
  29          * Clear all the cached instances.
  30          */
  31         static function clear() {
  32                 self::$instances = array();
  33         }
  34
  35         /**
  36          * Create a new cache object of the specified type.
  37          *
  38          * @param $id
  39          *
  40          * @return ObjectCache
  41          */
  42         static function newFromId( $id ) {
  43                 global $wgObjectCaches;
  44
  45                 if ( !isset( $wgObjectCaches[$id] ) ) {
  46                         throw new MWException( "Invalid object cache type \"$id\" requested. " .
  47                                 "It is not present in \$wgObjectCaches." );
  48                 }
  49
  50                 return self::newFromParams( $wgObjectCaches[$id] );
  51         }
  52
  53         /**
  54          * Create a new cache object from parameters
  55          *
  56          * @param $params array
  57          *
  58          * @return ObjectCache
  59          */
  60         static function newFromParams( $params ) {
  61                 if ( isset( $params['factory'] ) ) {
  62                         return call_user_func( $params['factory'], $params );
  63                 } elseif ( isset( $params['class'] ) ) {
  64                         $class = $params['class'];
  65                         return new $class( $params );
  66                 } else {
  67                         throw new MWException( "The definition of cache type \"" . print_r( $params, true ) . "\" lacks both " .
  68                                 "factory and class parameters." );
  69                 }
  70         }
  71
  72         /**
  73          * Factory function referenced from DefaultSettings.php for CACHE_ANYTHING
  74          *
  75          * CACHE_ANYTHING means that stuff has to be cached, not caching is not an option.
  76          * If a caching method is configured for any of the main caches ($wgMainCacheType,
  77          * $wgMessageCacheType, $wgParserCacheType), then CACHE_ANYTHING will effectively
  78          * be an alias to the configured cache choice for that.
  79          * If no cache choice is configured (by default $wgMainCacheType is CACHE_NONE),
  80          * then CACHE_ANYTHING will forward to CACHE_DB.
  81          */
  82         static function newAnything( $params ) {
  83                 global $wgMainCacheType, $wgMessageCacheType, $wgParserCacheType;
  84                 $candidates = array( $wgMainCacheType, $wgMessageCacheType, $wgParserCacheType );
  85                 foreach ( $candidates as $candidate ) {
  86                         if ( $candidate !== CACHE_NONE && $candidate !== CACHE_ANYTHING ) {
  87                                 return self::getInstance( $candidate );
  88                         }
  89                 }
  90                 return self::getInstance( CACHE_DB );
  91         }
  92
  93         /**
  94          * Factory function referenced from DefaultSettings.php for CACHE_ACCEL.
  95          *
  96          * @return ObjectCache
  97          */
  98         static function newAccelerator( $params ) {
  99                 if ( function_exists( 'apc_fetch') ) {
 100                         $id = 'apc';
 101                 } elseif( function_exists( 'xcache_get' ) && wfIniGetBool( 'xcache.var_size' ) ) {
 102                         $id = 'xcache';
 103                 } elseif( function_exists( 'wincache_ucache_get' ) ) {
 104                         $id = 'wincache';
 105                 } else {
 106                         throw new MWException( "CACHE_ACCEL requested but no suitable object " .
 107                                 "cache is present. You may want to install APC." );
 108                 }
 109                 return self::newFromId( $id );
 110         }
 111
 112         /**
 113          * Factory function that creates a memcached client object.
 114          * The idea of this is that it might eventually detect and automatically
 115          * support the PECL extension, assuming someone can get it to compile.
 116          *
 117          * @param $params array
 118          *
 119          * @return MemcachedPhpBagOStuff
 120          */
 121         static function newMemcached( $params ) {
 122                 return new MemcachedPhpBagOStuff( $params );
 123         }
 124 }