Fix flush-like commit in DeferredUpdates.

[lhc/web/wiklou.git] / includes / BacklinkCache.php

diff --git a/includes/BacklinkCache.php b/includes/BacklinkCache.php
index 1194015..ba8691b 100644 (file)
--- a/includes/BacklinkCache.php
+++ b/includes/BacklinkCache.php
@@ -1,7 +1,28 @@
 <?php
 /**
- * File for BacklinkCache class
+ * Class for fetching backlink lists, approximate backlink counts and
+ * partitions.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
  * @file
+ * @author Tim Starling
+ * @copyright © 2009, Tim Starling, Domas Mituzas
+ * @copyright © 2010, Max Sem
+ * @copyright © 2011, Antoine Musso
  */
 
 /**
@@ -18,13 +39,10 @@
  * Introduced by r47317
  *
  * @internal documentation reviewed on 18 Mar 2011 by hashar
- *
- * @author Tim Starling
- * @copyright © 2009, Tim Starling, Domas Mituzas
- * @copyright © 2010, Max Sem
- * @copyright © 2011, Ashar Voultoiz
  */
 class BacklinkCache {
+       /** @var ProcessCacheLRU */
+       protected static $cache;
 
        /**
         * Multi dimensions array representing batches. Keys are:
@@ -65,12 +83,32 @@ class BacklinkCache {
 
        /**
         * Create a new BacklinkCache
-        * @param Title $title : Title object to create a backlink cache for.
+        *
+        * @param Title $title : Title object to create a backlink cache for
         */
-       function __construct( $title ) {
+       public function __construct( Title $title ) {
                $this->title = $title;
        }
 
+       /**
+        * Create a new BacklinkCache or reuse any existing one.
+        * Currently, only one cache instance can exist; callers that
+        * need multiple backlink cache objects should keep them in scope.
+        *
+        * @param Title $title : Title object to get a backlink cache for
+        * @return BacklinkCache
+        */
+       public static function get( Title $title ) {
+               if ( !self::$cache ) { // init cache
+                       self::$cache = new ProcessCacheLRU( 1 );
+               }
+               $dbKey = $title->getPrefixedDBkey();
+               if ( !self::$cache->has( $dbKey, 'obj' ) ) {
+                       self::$cache->set( $dbKey, 'obj', new self( $title ) );
+               }
+               return self::$cache->get( $dbKey, 'obj' );
+       }
+
        /**
         * Serialization handler, diasallows to serialize the database to prevent
         * failures after this class is deserialized from cache with dead DB
@@ -103,7 +141,7 @@ class BacklinkCache {
        /**
         * Get the slave connection to the database
         * When non existing, will initialize the connection.
-        * @return Database object
+        * @return DatabaseBase object
         */
        protected function getDB() {
                if ( !isset( $this->db ) ) {
@@ -179,6 +217,8 @@ class BacklinkCache {
        /**
         * Get the field name prefix for a given table
         * @param $table String
+        * @throws MWException
+        * @return null|string
         */
        protected function getPrefix( $table ) {
                static $prefixes = array(
@@ -206,6 +246,8 @@ class BacklinkCache {
         * Get the SQL condition array for selecting backlinks, with a join
         * on the page table.
         * @param $table String
+        * @throws MWException
+        * @return array|null
         */
        protected function getConditions( $table ) {
                $prefix = $this->getPrefix( $table );
@@ -247,8 +289,9 @@ class BacklinkCache {
                        default:
                                $conds = null;
                                wfRunHooks( 'BacklinkCacheGetConditions', array( $table, $this->title, &$conds ) );
-                               if( !$conds )
+                               if( !$conds ) {
                                        throw new MWException( "Invalid table \"$table\" in " . __CLASS__ );
+                               }
                }
 
                return $conds;
@@ -285,7 +328,7 @@ class BacklinkCache {
         */
        public function partition( $table, $batchSize ) {
 
-               // 1) try partition cache ... 
+               // 1) try partition cache ...
 
                if ( isset( $this->partitionCache[$table][$batchSize] ) ) {
                        wfDebug( __METHOD__ . ": got from partition cache\n" );
@@ -340,7 +383,8 @@ class BacklinkCache {
         * Partition a DB result with backlinks in it into batches
         * @param $res ResultWrapper database result
         * @param $batchSize integer
-        * @return array @see 
+        * @throws MWException
+        * @return array @see
         */
        protected function partitionResult( $res, $batchSize ) {
                $batches = array();