includes/ParserCache.php

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