1 files changed, 116 insertions, 0 deletions
diff --git a/includes/parser/ParserCache.php b/includes/parser/ParserCache.php
new file mode 100644
index 00000000..bf11da2e
--- /dev/null
+++ b/includes/parser/ParserCache.php
@@ -0,0 +1,116 @@
+<?php
+/**
+ * @ingroup Cache Parser
+ * @todo document
+ */
+class ParserCache {
+	/**
+	 * Get an instance of this object
+	 */
+	public static function &singleton() {
+		static $instance;
+		if ( !isset( $instance ) ) {
+			global $parserMemc;
+			$instance = new ParserCache( $parserMemc );
+		}
+		return $instance;
+	}
+
+	/**
+	 * Setup a cache pathway with a given back-end storage mechanism.
+	 * May be a memcached client or a BagOStuff derivative.
+	 *
+	 * @param object $memCached
+	 */
+	function __construct( &$memCached ) {
+		$this->mMemc =& $memCached;
+	}
+
+	function getKey( &$article, &$user ) {
+		global $action;
+		$hash = $user->getPageRenderingHash();
+		if( !$article->mTitle->quickUserCan( 'edit' ) ) {
+			// section edit links are suppressed even if the user has them on
+			$edit = '!edit=0';
+		} else {
+			$edit = '';
+		}
+		$pageid = intval( $article->getID() );
+		$renderkey = (int)($action == 'render');
+		$key = wfMemcKey( 'pcache', 'idhash', "$pageid-$renderkey!$hash$edit" );
+		return $key;
+	}
+
+	function getETag( &$article, &$user ) {
+		return 'W/"' . $this->getKey($article, $user) . "--" . $article->mTouched. '"';
+	}
+
+	function get( &$article, &$user ) {
+		global $wgCacheEpoch;
+		$fname = 'ParserCache::get';
+		wfProfileIn( $fname );
+
+		$key = $this->getKey( $article, $user );
+
+		wfDebug( "Trying parser cache $key\n" );
+		$value = $this->mMemc->get( $key );
+		if ( is_object( $value ) ) {
+			wfDebug( "Found.\n" );
+			# Delete if article has changed since the cache was made
+			$canCache = $article->checkTouched();
+			$cacheTime = $value->getCacheTime();
+			$touched = $article->mTouched;
+			if ( !$canCache || $value->expired( $touched ) ) {
+				if ( !$canCache ) {
+					wfIncrStats( "pcache_miss_invalid" );
+					wfDebug( "Invalid cached redirect, touched $touched, epoch $wgCacheEpoch, cached $cacheTime\n" );
+				} else {
+					wfIncrStats( "pcache_miss_expired" );
+					wfDebug( "Key expired, touched $touched, epoch $wgCacheEpoch, cached $cacheTime\n" );
+				}
+				$this->mMemc->delete( $key );
+				$value = false;
+			} else {
+				if ( isset( $value->mTimestamp ) ) {
+					$article->mTimestamp = $value->mTimestamp;
+				}
+				wfIncrStats( "pcache_hit" );
+			}
+		} else {
+			wfDebug( "Parser cache miss.\n" );
+			wfIncrStats( "pcache_miss_absent" );
+			$value = false;
+		}
+
+		wfProfileOut( $fname );
+		return $value;
+	}
+
+	function save( $parserOutput, &$article, &$user ){
+		global $wgParserCacheExpireTime;
+		$key = $this->getKey( $article, $user );
+
+		if( $parserOutput->getCacheTime() != -1 ) {
+
+			$now = wfTimestampNow();
+			$parserOutput->setCacheTime( $now );
+
+			// Save the timestamp so that we don't have to load the revision row on view
+			$parserOutput->mTimestamp = $article->getTimestamp();
+
+			$parserOutput->mText .= "\n<!-- Saved in parser cache with key $key and timestamp $now -->\n";
+			wfDebug( "Saved in parser cache with key $key and timestamp $now\n" );
+
+			if( $parserOutput->containsOldMagic() ){
+				$expire = 3600; # 1 hour
+			} else {
+				$expire = $wgParserCacheExpireTime;
+			}
+			$this->mMemc->set( $key, $parserOutput, $expire );
+
+		} else {
+			wfDebug( "Parser output was marked as uncacheable and has not been saved.\n" );
+		}
+	}
+
+}