From b728d6920b05c8b667651f7e99d749496474f02b Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Wed, 20 Aug 2014 16:41:59 -0700
Subject: [PATCH] Made getCachedRevisionObject() use MapCacheLRU

* Previously the cache size was unbounded and leaky
* Also made MapCacheLRU handle null values properly

Change-Id: Ia02258cf051e1ccf11457c758741b8c7922afe89
---
 includes/cache/MapCacheLRU.php          |  6 +++---
 includes/parser/CoreParserFunctions.php | 13 ++++++++-----
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/includes/cache/MapCacheLRU.php b/includes/cache/MapCacheLRU.php
index a22d8023d6..95e3af769e 100644
--- a/includes/cache/MapCacheLRU.php
+++ b/includes/cache/MapCacheLRU.php
@@ -57,7 +57,7 @@ class MapCacheLRU {
 	 * @return void
 	 */
 	public function set( $key, $value ) {
-		if ( isset( $this->cache[$key] ) ) {
+		if ( array_key_exists( $key, $this->cache ) ) {
 			$this->ping( $key ); // push to top
 		} elseif ( count( $this->cache ) >= $this->maxCacheKeys ) {
 			reset( $this->cache );
@@ -74,7 +74,7 @@ class MapCacheLRU {
 	 * @return bool
 	 */
 	public function has( $key ) {
-		return isset( $this->cache[$key] );
+		return array_key_exists( $key, $this->cache );
 	}
 
 	/**
@@ -86,7 +86,7 @@ class MapCacheLRU {
 	 * @return mixed
 	 */
 	public function get( $key ) {
-		if ( isset( $this->cache[$key] ) ) {
+		if ( array_key_exists( $key, $this->cache ) ) {
 			$this->ping( $key ); // push to top
 			return $this->cache[$key];
 		} else {
diff --git a/includes/parser/CoreParserFunctions.php b/includes/parser/CoreParserFunctions.php
index cd1f32dc4c..983fc1489f 100644
--- a/includes/parser/CoreParserFunctions.php
+++ b/includes/parser/CoreParserFunctions.php
@@ -1000,7 +1000,10 @@ class CoreParserFunctions {
 	 * @since 1.23
 	 */
 	private static function getCachedRevisionObject( $parser, $title = null ) {
-		static $cache = array();
+		static $cache = null;
+		if ( !isset( $cache ) ) {
+			$cache = new MapCacheLRU( 100 );
+		}
 
 		if ( is_null( $title ) ) {
 			return null;
@@ -1021,21 +1024,21 @@ class CoreParserFunctions {
 		// Normalize name for cache
 		$page = $title->getPrefixedDBkey();
 
-		if ( array_key_exists( $page, $cache ) ) { // cache contains null values
-			return $cache[$page];
+		if ( $cache->has( $page ) ) { // cache contains null values
+			return $cache->get( $page );
 		}
 		if ( $parser->incrementExpensiveFunctionCount() ) {
 			$rev = Revision::newFromTitle( $title, false, Revision::READ_NORMAL );
 			$pageID = $rev ? $rev->getPage() : 0;
 			$revID = $rev ? $rev->getId() : 0;
-			$cache[$page] = $rev; // maybe null
+			$cache->set( $page, $rev ); // maybe null
 
 			// Register dependency in templatelinks
 			$parser->getOutput()->addTemplate( $title, $pageID, $revID );
 
 			return $rev;
 		}
-		$cache[$page] = null;
+		$cache->set( $page, null );
 		return null;
 	}
 
-- 
2.20.1