+ // Should mean that database cannot be used, but check
+ protected $mDisable;
+
+ /// Lifetime for cache, used by object caching
+ protected $mExpiry;
+
+ /**
+ * Message cache has it's own parser which it uses to transform
+ * messages.
+ */
+ protected $mParserOptions, $mParser;
+
+ /// Variable for tracking which variables are already loaded
+ protected $mLoadedLanguages = array();
+
+ /**
+ * Used for automatic detection of most used messages.
+ */
+ protected $mRequestedMessages = array();
+
+ /**
+ * How long the message request counts are stored. Longer period gives
+ * better sample, but also takes longer to adapt changes. The counts
+ * are aggregrated per day, regardless of the value of this variable.
+ */
+ protected static $mAdaptiveDataAge = 604800; // Is 7*24*3600
+
+ /**
+ * Filter the tail of less used messages that are requested more seldom
+ * than this factor times the number of request of most requested message.
+ * These messages are not loaded in the default set, but are still cached
+ * individually on demand with the normal cache expiry time.
+ */
+ protected static $mAdaptiveInclusionThreshold = 0.05;
+
+ /**
+ * Singleton instance
+ */
+ private static $instance;
+
+ /**
+ * Get the signleton instance of this class
+ *
+ * @since 1.18
+ * @return MessageCache object
+ */
+ public static function singleton() {
+ if ( is_null( self::$instance ) ) {
+ global $wgUseDatabaseMessages, $wgMsgCacheExpiry;
+ self::$instance = new self( wfGetMessageCacheStorage(), $wgUseDatabaseMessages, $wgMsgCacheExpiry );
+ }
+ return self::$instance;
+ }
+
+ /**
+ * Destroy the singleton instance
+ *
+ * @since 1.18
+ */
+ public static function destroyInstance() {
+ self::$instance = null;
+ }