From 83b50484e0023ec16f24f65c29009dcb2e7b5fd5 Mon Sep 17 00:00:00 2001
From: Timo Tijhof <krinklemail@gmail.com>
Date: Fri, 30 Jun 2017 21:19:31 -0700
Subject: [PATCH] Skin: Use WANObjectCache for sitenotice caching

* Move the md5() hash to the cache key, this makes it much safer
  after a change happens by avoiding write competitions between different
  servers and db slaves. It also allows an undo to re-use the existing
  cache if it still exists.

  In addition, it enables idiomatic use of getWithSetCallback given
  that get and set are now logically separated.

* Avoid fragile re-use of variable names. Previously it read the
  original $notice value at multiple points but also setting $notice
  to $parsed after a certain point. Consistently use $parsed only.

(Ref T115890.)

Change-Id: I5488cc894ff1544e6c20b7d51a7a2adfc292c4ec
---
 includes/skins/Skin.php | 44 ++++++++++++++++++++---------------------
 1 file changed, 22 insertions(+), 22 deletions(-)

diff --git a/includes/skins/Skin.php b/includes/skins/Skin.php
index e9d2f076b1..3e8b3f23a0 100644
--- a/includes/skins/Skin.php
+++ b/includes/skins/Skin.php
@@ -20,6 +20,8 @@
  * @file
  */
 
+use MediaWiki\MediaWikiServices;
+
 /**
  * @defgroup Skins Skins
  */
@@ -1259,7 +1261,7 @@ abstract class Skin extends ContextSource {
 		};
 
 		if ( $wgEnableSidebarCache ) {
-			$cache = ObjectCache::getMainWANInstance();
+			$cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
 			$sidebar = $cache->getWithSetCallback(
 				$cache->makeKey( 'sidebar', $this->getLanguage()->getCode() ),
 				MessageCache::singleton()->isDisabled()
@@ -1506,29 +1508,27 @@ abstract class Skin extends ContextSource {
 			$notice = $msg->plain();
 		}
 
-		$cache = wfGetCache( CACHE_ANYTHING );
-		// Use the extra hash appender to let eg SSL variants separately cache.
-		$key = $cache->makeKey( $name . $wgRenderHashAppend );
-		$cachedNotice = $cache->get( $key );
-		if ( is_array( $cachedNotice ) ) {
-			if ( md5( $notice ) == $cachedNotice['hash'] ) {
-				$notice = $cachedNotice['html'];
-			} else {
-				$needParse = true;
+		$cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
+		$parsed = $cache->getWithSetCallback(
+			// Use the extra hash appender to let eg SSL variants separately cache
+			// Key is verified with md5 hash of unparsed wikitext
+			$cache->makeKey( $name, $wgRenderHashAppend, md5( $notice ) ),
+			// TTL in seconds
+			600,
+			function () use ( $notice ) {
+				return $this->getOutput()->parse( $notice );
 			}
-		} else {
-			$needParse = true;
-		}
-
-		if ( $needParse ) {
-			$parsed = $this->getOutput()->parse( $notice );
-			$cache->set( $key, [ 'html' => $parsed, 'hash' => md5( $notice ) ], 600 );
-			$notice = $parsed;
-		}
+		);
 
-		$notice = Html::rawElement( 'div', [ 'id' => 'localNotice',
-			'lang' => $wgContLang->getHtmlCode(), 'dir' => $wgContLang->getDir() ], $notice );
-		return $notice;
+		return Html::rawElement(
+			'div',
+			[
+				'id' => 'localNotice',
+				'lang' => $wgContLang->getHtmlCode(),
+				'dir' => $wgContLang->getDir()
+			],
+			$parsed
+		);
 	}
 
 	/**
-- 
2.20.1