includes/ParserCache.php

   1 <?php
   2 /**
   3  *
   4  * @package MediaWiki
   5  * @subpackage Cache
   6  */
   7
   8 /**
   9  *
  10  * @package MediaWiki
  11  */
  12 class ParserCache {
  13         /**
  14          * Setup a cache pathway with a given back-end storage mechanism.
  15          * May be a memcached client or a BagOStuff derivative.
  16          *
  17          * @param object $memCached
  18          */
  19         function ParserCache( &$memCached ) {
  20                 $this->mMemc =& $memCached;
  21         }
  22
  23         function getKey( &$article, &$user ) {
  24                 global $wgDBname;
  25                 $hash = $user->getPageRenderingHash();
  26                 $pageid = intval( $article->getID() );
  27                 $key = "$wgDBname:pcache:idhash:$pageid-$hash";
  28                 return $key;
  29         }
  30
  31         function get( &$article, &$user ) {
  32                 global $wgCacheEpoch;
  33                 $fname = 'ParserCache::get';
  34                 wfProfileIn( $fname );
  35
  36                 $hash = $user->getPageRenderingHash();
  37                 $pageid = intval( $article->getID() );
  38                 $key = $this->getKey( $article, $user );
  39
  40                 wfDebug( "Trying parser cache $key\n" );
  41                 $value = $this->mMemc->get( $key );
  42                 if ( is_object( $value ) ) {
  43                         wfDebug( "Found.\n" );
  44                         # Delete if article has changed since the cache was made
  45                         $canCache = $article->checkTouched();
  46                         $cacheTime = $value->getCacheTime();
  47                         $touched = $article->mTouched;
  48                         if ( !$canCache || $value->expired( $touched ) ) {
  49                                 if ( !$canCache ) {
  50                                         $this->incrStats( "pcache_miss_invalid" );
  51                                         wfDebug( "Invalid cached redirect, touched $touched, epoch $wgCacheEpoch, cached $cacheTime\n" );
  52                                 } else {
  53                                         $this->incrStats( "pcache_miss_expired" );
  54                                         wfDebug( "Key expired, touched $touched, epoch $wgCacheEpoch, cached $cacheTime\n" );
  55                                 }
  56                                 $this->mMemc->delete( $key );
  57                                 $value = false;
  58
  59                         } else {
  60                                 $this->incrStats( "pcache_hit" );
  61                         }
  62                 } else {
  63                         wfDebug( "Parser cache miss.\n" );
  64                         $this->incrStats( "pcache_miss_absent" );
  65                         $value = false;
  66                 }
  67
  68                 wfProfileOut( $fname );
  69                 return $value;
  70         }
  71
  72         function save( $parserOutput, &$article, &$user ){
  73                 $key = $this->getKey( $article, $user );
  74                 $now = wfTimestampNow();
  75                 $parserOutput->setCacheTime( $now );
  76                 $parserOutput->mText .= "\n<!-- Saved in parser cache with key $key and timestamp $now -->\n";
  77                 wfDebug( "Saved in parser cache with key $key and timestamp $now\n" );
  78
  79                 if( $parserOutput->containsOldMagic() ){
  80                         $expire = 3600; # 1 hour
  81                 } else {
  82                         $expire = 86400; # 1 day
  83                 }
  84                 $this->mMemc->set( $key, $parserOutput, $expire );
  85         }
  86
  87         function incrStats( $key ) {
  88                 global $wgDBname, $wgMemc;
  89                 $key = "$wgDBname:stats:$key";
  90                 if ( is_null( $wgMemc->incr( $key ) ) ) {
  91                         $wgMemc->add( $key, 1 );
  92                 }
  93         }
  94 }
  95
  96
  97 ?>