14 * Get an instance of this object
16 public static function &singleton() {
18 if ( !isset( $instance ) ) {
20 $instance = new ParserCache( $parserMemc );
26 * Setup a cache pathway with a given back-end storage mechanism.
27 * May be a memcached client or a BagOStuff derivative.
29 * @param object $memCached
31 function ParserCache( &$memCached ) {
32 $this->mMemc
=& $memCached;
35 function getKey( &$article, &$user ) {
37 $hash = $user->getPageRenderingHash();
38 if( !$article->mTitle
->userCanEdit() ) {
39 // section edit links are suppressed even if the user has them on
44 $pageid = intval( $article->getID() );
45 $renderkey = (int)($action == 'render');
46 $key = wfMemcKey( 'pcache', 'idhash', "$pageid-$renderkey!$hash$edit" );
50 function getETag( &$article, &$user ) {
51 return 'W/"' . $this->getKey($article, $user) . "--" . $article->mTouched
. '"';
54 function get( &$article, &$user ) {
56 $fname = 'ParserCache::get';
57 wfProfileIn( $fname );
59 $key = $this->getKey( $article, $user );
61 wfDebug( "Trying parser cache $key\n" );
62 $value = $this->mMemc
->get( $key );
63 if ( is_object( $value ) ) {
64 wfDebug( "Found.\n" );
65 # Delete if article has changed since the cache was made
66 $canCache = $article->checkTouched();
67 $cacheTime = $value->getCacheTime();
68 $touched = $article->mTouched
;
69 if ( !$canCache ||
$value->expired( $touched ) ) {
71 wfIncrStats( "pcache_miss_invalid" );
72 wfDebug( "Invalid cached redirect, touched $touched, epoch $wgCacheEpoch, cached $cacheTime\n" );
74 wfIncrStats( "pcache_miss_expired" );
75 wfDebug( "Key expired, touched $touched, epoch $wgCacheEpoch, cached $cacheTime\n" );
77 $this->mMemc
->delete( $key );
80 if ( isset( $value->mTimestamp
) ) {
81 $article->mTimestamp
= $value->mTimestamp
;
83 wfIncrStats( "pcache_hit" );
86 wfDebug( "Parser cache miss.\n" );
87 wfIncrStats( "pcache_miss_absent" );
91 wfProfileOut( $fname );
95 function save( $parserOutput, &$article, &$user ){
96 global $wgParserCacheExpireTime;
97 $key = $this->getKey( $article, $user );
99 if( $parserOutput->getCacheTime() != -1 ) {
101 $now = wfTimestampNow();
102 $parserOutput->setCacheTime( $now );
104 // Save the timestamp so that we don't have to load the revision row on view
105 $parserOutput->mTimestamp
= $article->getTimestamp();
107 $parserOutput->mText
.= "\n<!-- Saved in parser cache with key $key and timestamp $now -->\n";
108 wfDebug( "Saved in parser cache with key $key and timestamp $now\n" );
110 if( $parserOutput->containsOldMagic() ){
111 $expire = 3600; # 1 hour
113 $expire = $wgParserCacheExpireTime;
115 $this->mMemc
->set( $key, $parserOutput, $expire );
118 wfDebug( "Parser output was marked as uncacheable and has not been saved.\n" );