Merge "Document parser cache key control."

diff --combined includes/parser/ParserCache.php
index 9eaa3e2,6ab8314..040c74f
--- 1/includes/parser/ParserCache.php
--- 2/includes/parser/ParserCache.php
+++ b/includes/parser/ParserCache.php
@@@ -27,6 -27,8 +27,6 @@@
   */
  class ParserCache {
        private $mMemc;
 -      const try116cache = false; /* Only useful $wgParserCacheExpireTime after updating to 1.17 */
 -
        /**
         * Get an instance of this object
         *
@@@ -112,7 -114,14 +112,14 @@@
        }
  
        /**
-        * Used to provide a unique id for the PoolCounter.
+        * Generates a key for caching the given article considering
+        * the given parser options.
+        *
+        * @note Which parser options influence the cache key
+        * is controlled via ParserOutput::recordOption() or
+        * ParserOptions::addExtraKey().
+        *
+        * @note Used by Article to provide a unique id for the PoolCounter.
         * It would be preferable to have this code in get()
         * instead of having Article looking in our internals.
         *
@@@ -141,10 -150,11 +148,11 @@@
                                return false;
                        }
  
+                       // $optionsKey->mUsedOptions is set by save() by calling ParserOutput::getUsedOptions()
                        $usedOptions = $optionsKey->mUsedOptions;
                        wfDebug( "Parser cache options found.\n" );
                } else {
 -                      if ( !$useOutdated && !self::try116cache ) {
 +                      if ( !$useOutdated ) {
                                return false;
                        }
                        $usedOptions = ParserOptions::legacyOptions();
@@@ -184,6 -194,12 +192,6 @@@
                }
  
                $value = $this->mMemc->get( $parserOutputKey );
 -              if ( self::try116cache && !$value && strpos( $value, '*' ) !== -1 ) {
 -                      wfDebug( "New format parser cache miss.\n" );
 -                      $parserOutputKey = $this->getParserOutputKey( $article,
 -                              $popts->optionsHash( ParserOptions::legacyOptions(), $article->getTitle() ) );
 -                      $value = $this->mMemc->get( $parserOutputKey );
 -              }
                if ( !$value ) {
                        wfDebug( "ParserOutput cache miss.\n" );
                        wfIncrStats( "pcache_miss_absent" );
@@@ -213,11 -229,11 +221,11 @@@
  
        /**
         * @param ParserOutput $parserOutput
 -       * @param Article $article
 +       * @param WikiPage $page
         * @param ParserOptions $popts
         * @param string $cacheTime Time when the cache was generated
         */
 -      public function save( $parserOutput, $article, $popts, $cacheTime = null ) {
 +      public function save( $parserOutput, $page, $popts, $cacheTime = null ) {
                $expire = $parserOutput->getCacheExpiry();
                if ( $expire > 0 ) {
                        $cacheTime = $cacheTime ?: wfTimestampNow();
@@@ -231,11 -247,11 +239,11 @@@
  
                        $optionsKey->setContainsOldMagic( $parserOutput->containsOldMagic() );
  
 -                      $parserOutputKey = $this->getParserOutputKey( $article,
 -                              $popts->optionsHash( $optionsKey->mUsedOptions, $article->getTitle() ) );
 +                      $parserOutputKey = $this->getParserOutputKey( $page,
 +                              $popts->optionsHash( $optionsKey->mUsedOptions, $page->getTitle() ) );
  
                        // Save the timestamp so that we don't have to load the revision row on view
 -                      $parserOutput->setTimestamp( $article->getTimestamp() );
 +                      $parserOutput->setTimestamp( $page->getTimestamp() );
  
                        $parserOutput->mText .= "\n<!-- Saved in parser cache with key $parserOutputKey and timestamp $cacheTime\n -->\n";
                        wfDebug( "Saved in parser cache with key $parserOutputKey and timestamp $cacheTime\n" );
@@@ -244,7 -260,7 +252,7 @@@
                        $this->mMemc->set( $parserOutputKey, $parserOutput, $expire );
  
                        // ...and its pointer
 -                      $this->mMemc->set( $this->getOptionsKey( $article ), $optionsKey, $expire );
 +                      $this->mMemc->set( $this->getOptionsKey( $page ), $optionsKey, $expire );
                } else {
                        wfDebug( "Parser output was marked as uncacheable and has not been saved.\n" );
                }

diff --combined includes/parser/ParserOutput.php
index 8cd978b,57b8ebc..c021bea
--- 1/includes/parser/ParserOutput.php
--- 2/includes/parser/ParserOutput.php
+++ b/includes/parser/ParserOutput.php
@@@ -59,8 -59,8 +59,8 @@@ class ParserOutput extends CacheTime 
        const EDITSECTION_REGEX = '#<(?:mw:)?editsection page="(.*?)" section="(.*?)"(?:/>|>(.*?)(</(?:mw:)?editsection>))#';
  
        function __construct( $text = '', $languageLinks = array(), $categoryLinks = array(),
 -              $containsOldMagic = false, $titletext = '' )
 -      {
 +              $containsOldMagic = false, $titletext = ''
 +      ) {
                $this->mText = $text;
                $this->mLanguageLinks = $languageLinks;
                $this->mCategories = $categoryLinks;
@@@ -279,10 -279,10 +279,10 @@@
         * @throws MWException if given invalid input
         */
        function addInterwikiLink( $title ) {
 -              $prefix = $title->getInterwiki();
 -              if ( $prefix == '' ) {
 +              if ( !$title->isExternal() ) {
                        throw new MWException( 'Non-interwiki link passed, internal parser error.' );
                }
 +              $prefix = $title->getInterwiki();
                if ( !isset( $this->mInterwikiLinks[$prefix] ) ) {
                        $this->mInterwikiLinks[$prefix] = array();
                }
@@@ -453,10 -453,15 +453,15 @@@
        }
  
        /**
-        * Callback passed by the Parser to the ParserOptions to keep track of which options are used.
-        * @access private
+        * Tags a parser option for use in the cache key for this parser output.
+        * Registered as a watcher at ParserOptions::registerWatcher() by Parser::clearState().
+        *
+        * @see ParserCache::getKey
+        * @see ParserCache::save
+        * @see ParserOptions::addExtraKey
+        * @see ParserOptions::optionsHash
         */
-       function recordOption( $option ) {
+       public function recordOption( $option ) {
                $this->mAccessedOptions[$option] = true;
        }