ObjectCache.php

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<?php
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\MediaWikiServices;
use MediaWiki\Services\ServiceDisabledException;

class ObjectCache {
    public static $instances = [];
    public static $wanInstances = [];

    public static function getInstance( $id ) {
        if ( !isset( self::$instances[$id] ) ) {
            self::$instances[$id] = self::newFromId( $id );
        }

        return self::$instances[$id];
    }

    public static function getWANInstance( $id ) {
        if ( !isset( self::$wanInstances[$id] ) ) {
            self::$wanInstances[$id] = self::newWANCacheFromId( $id );
        }

        return self::$wanInstances[$id];
    }

    public static function newFromId( $id ) {
        global $wgObjectCaches;

        if ( !isset( $wgObjectCaches[$id] ) ) {
            throw new MWException( "Invalid object cache type \"$id\" requested. " .
                "It is not present in \$wgObjectCaches." );
        }

        return self::newFromParams( $wgObjectCaches[$id] );
    }

    public static function getDefaultKeyspace() {
        global $wgCachePrefix;

        $keyspace = $wgCachePrefix;
        if ( is_string( $keyspace ) && $keyspace !== '' ) {
            return $keyspace;
        }

        return wfWikiID();
    }

    public static function newFromParams( $params ) {
        if ( isset( $params['loggroup'] ) ) {
            $params['logger'] = LoggerFactory::getInstance( $params['loggroup'] );
        } else {
            $params['logger'] = LoggerFactory::getInstance( 'objectcache' );
        }
        if ( !isset( $params['keyspace'] ) ) {
            $params['keyspace'] = self::getDefaultKeyspace();
        }
        if ( isset( $params['factory'] ) ) {
            return call_user_func( $params['factory'], $params );
        } elseif ( isset( $params['class'] ) ) {
            $class = $params['class'];
            // Automatically set the 'async' update handler
            $params['asyncHandler'] = isset( $params['asyncHandler'] )
                ? $params['asyncHandler']
                : 'DeferredUpdates::addCallableUpdate';
            // Enable reportDupes by default
            $params['reportDupes'] = isset( $params['reportDupes'] )
                ? $params['reportDupes']
                : true;
            // Do b/c logic for MemcachedBagOStuff
            if ( is_subclass_of( $class, 'MemcachedBagOStuff' ) ) {
                if ( !isset( $params['servers'] ) ) {
                    $params['servers'] = $GLOBALS['wgMemCachedServers'];
                }
                if ( !isset( $params['debug'] ) ) {
                    $params['debug'] = $GLOBALS['wgMemCachedDebug'];
                }
                if ( !isset( $params['persistent'] ) ) {
                    $params['persistent'] = $GLOBALS['wgMemCachedPersistent'];
                }
                if ( !isset( $params['timeout'] ) ) {
                    $params['timeout'] = $GLOBALS['wgMemCachedTimeout'];
                }
            }
            return new $class( $params );
        } else {
            throw new MWException( "The definition of cache type \""
                . print_r( $params, true ) . "\" lacks both "
                . "factory and class parameters." );
        }
    }

    public static function newAnything( $params ) {
        global $wgMainCacheType, $wgMessageCacheType, $wgParserCacheType;
        $candidates = [ $wgMainCacheType, $wgMessageCacheType, $wgParserCacheType ];
        foreach ( $candidates as $candidate ) {
            if ( $candidate !== CACHE_NONE && $candidate !== CACHE_ANYTHING ) {
                return self::getInstance( $candidate );
            }
        }

        try {
            // Make sure we actually have a DB backend before falling back to CACHE_DB
            MediaWikiServices::getInstance()->getDBLoadBalancer();
            $candidate = CACHE_DB;
        } catch ( ServiceDisabledException $e ) {
            // The LoadBalancer is disabled, probably because
            // MediaWikiServices::disableStorageBackend was called.
            $candidate = CACHE_NONE;
        }

        return self::getInstance( $candidate );
    }

    public static function getLocalServerInstance( $fallback = CACHE_NONE ) {
        if ( function_exists( 'apc_fetch' ) ) {
            $id = 'apc';
        } elseif ( function_exists( 'xcache_get' ) && wfIniGetBool( 'xcache.var_size' ) ) {
            $id = 'xcache';
        } elseif ( function_exists( 'wincache_ucache_get' ) ) {
            $id = 'wincache';
        } else {
            if ( is_array( $fallback ) ) {
                $id = isset( $fallback['fallback'] ) ? $fallback['fallback'] : CACHE_NONE;
            } else {
                $id = $fallback;
            }
        }

        return self::getInstance( $id );
    }

    public static function newAccelerator( $params = [], $fallback = null ) {
        if ( $fallback === null ) {
            if ( is_array( $params ) && isset( $params['fallback'] ) ) {
                $fallback = $params['fallback'];
            } elseif ( !is_array( $params ) ) {
                $fallback = $params;
            }
        }

        return self::getLocalServerInstance( $fallback );
    }

    public static function newWANCacheFromId( $id ) {
        global $wgWANObjectCaches;

        if ( !isset( $wgWANObjectCaches[$id] ) ) {
            throw new MWException( "Invalid object cache type \"$id\" requested. " .
                "It is not present in \$wgWANObjectCaches." );
        }

        $params = $wgWANObjectCaches[$id];
        foreach ( $params['channels'] as $action => $channel ) {
            $params['relayers'][$action] = MediaWikiServices::getInstance()->getEventRelayerGroup()
                ->getRelayer( $channel );
            $params['channels'][$action] = $channel;
        }
        $params['cache'] = self::newFromId( $params['cacheId'] );
        if ( isset( $params['loggroup'] ) ) {
            $params['logger'] = LoggerFactory::getInstance( $params['loggroup'] );
        } else {
            $params['logger'] = LoggerFactory::getInstance( 'objectcache' );
        }
        $class = $params['class'];

        return new $class( $params );
    }

    public static function getLocalClusterInstance() {
        global $wgMainCacheType;

        return self::getInstance( $wgMainCacheType );
    }

    public static function getMainWANInstance() {
        global $wgMainWANCache;

        return self::getWANInstance( $wgMainWANCache );
    }

    public static function getMainStashInstance() {
        global $wgMainStash;

        return self::getInstance( $wgMainStash );
    }

    public static function clear() {
        self::$instances = [];
        self::$wanInstances = [];
    }
}