1 files changed, 354 insertions, 0 deletions
diff --git a/www/wiki/includes/parser/ParserCache.php b/www/wiki/includes/parser/ParserCache.php
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+++ b/www/wiki/includes/parser/ParserCache.php
@@ -0,0 +1,354 @@
+<?php
+/**
+ * Cache for outputs of the PHP parser
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @ingroup Cache Parser
+ */
+
+use MediaWiki\MediaWikiServices;
+
+/**
+ * @ingroup Cache Parser
+ * @todo document
+ */
+class ParserCache {
+	/**
+	 * Constants for self::getKey()
+	 * @since 1.30
+	 */
+
+	/** Use only current data */
+	const USE_CURRENT_ONLY = 0;
+
+	/** Use expired data if current data is unavailable */
+	const USE_EXPIRED = 1;
+
+	/** Use expired data or data from different revisions if current data is unavailable */
+	const USE_OUTDATED = 2;
+
+	/**
+	 * Use expired data and data from different revisions, and if all else
+	 * fails vary on all variable options
+	 */
+	const USE_ANYTHING = 3;
+
+	/** @var BagOStuff */
+	private $mMemc;
+
+	/**
+	 * Anything cached prior to this is invalidated
+	 *
+	 * @var string
+	 */
+	private $cacheEpoch;
+	/**
+	 * Get an instance of this object
+	 *
+	 * @deprecated since 1.30, use MediaWikiServices instead
+	 * @return ParserCache
+	 */
+	public static function singleton() {
+		return MediaWikiServices::getInstance()->getParserCache();
+	}
+
+	/**
+	 * Setup a cache pathway with a given back-end storage mechanism.
+	 *
+	 * This class use an invalidation strategy that is compatible with
+	 * MultiWriteBagOStuff in async replication mode.
+	 *
+	 * @param BagOStuff $cache
+	 * @param string $cacheEpoch Anything before this timestamp is invalidated
+	 * @throws MWException
+	 */
+	public function __construct( BagOStuff $cache, $cacheEpoch = '20030516000000' ) {
+		$this->mMemc = $cache;
+		$this->cacheEpoch = $cacheEpoch;
+	}
+
+	/**
+	 * @param WikiPage $article
+	 * @param string $hash
+	 * @return mixed|string
+	 */
+	protected function getParserOutputKey( $article, $hash ) {
+		global $wgRequest;
+
+		// idhash seem to mean 'page id' + 'rendering hash' (r3710)
+		$pageid = $article->getId();
+		$renderkey = (int)( $wgRequest->getVal( 'action' ) == 'render' );
+
+		$key = $this->mMemc->makeKey( 'pcache', 'idhash', "{$pageid}-{$renderkey}!{$hash}" );
+		return $key;
+	}
+
+	/**
+	 * @param WikiPage $page
+	 * @return mixed|string
+	 */
+	protected function getOptionsKey( $page ) {
+		return $this->mMemc->makeKey( 'pcache', 'idoptions', $page->getId() );
+	}
+
+	/**
+	 * @param WikiPage $page
+	 * @since 1.28
+	 */
+	public function deleteOptionsKey( $page ) {
+		$this->mMemc->delete( $this->getOptionsKey( $page ) );
+	}
+
+	/**
+	 * Provides an E-Tag suitable for the whole page. Note that $article
+	 * is just the main wikitext. The E-Tag has to be unique to the whole
+	 * page, even if the article itself is the same, so it uses the
+	 * complete set of user options. We don't want to use the preference
+	 * of a different user on a message just because it wasn't used in
+	 * $article. For example give a Chinese interface to a user with
+	 * English preferences. That's why we take into account *all* user
+	 * options. (r70809 CR)
+	 *
+	 * @param WikiPage $article
+	 * @param ParserOptions $popts
+	 * @return string
+	 */
+	public function getETag( $article, $popts ) {
+		return 'W/"' . $this->getParserOutputKey( $article,
+			$popts->optionsHash( ParserOptions::allCacheVaryingOptions(), $article->getTitle() ) ) .
+				"--" . $article->getTouched() . '"';
+	}
+
+	/**
+	 * Retrieve the ParserOutput from ParserCache, even if it's outdated.
+	 * @param WikiPage $article
+	 * @param ParserOptions $popts
+	 * @return ParserOutput|bool False on failure
+	 */
+	public function getDirty( $article, $popts ) {
+		$value = $this->get( $article, $popts, true );
+		return is_object( $value ) ? $value : false;
+	}
+
+	/**
+	 * 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.
+	 *
+	 * @param WikiPage $article
+	 * @param ParserOptions $popts
+	 * @param int|bool $useOutdated One of the USE constants. For backwards
+	 *  compatibility, boolean false is treated as USE_CURRENT_ONLY and
+	 *  boolean true is treated as USE_ANYTHING.
+	 * @return bool|mixed|string
+	 * @since 1.30 Changed $useOutdated to an int and added the non-boolean values
+	 */
+	public function getKey( $article, $popts, $useOutdated = self::USE_ANYTHING ) {
+		if ( is_bool( $useOutdated ) ) {
+			$useOutdated = $useOutdated ? self::USE_ANYTHING : self::USE_CURRENT_ONLY;
+		}
+
+		if ( $popts instanceof User ) {
+			wfWarn( "Use of outdated prototype ParserCache::getKey( &\$article, &\$user )\n" );
+			$popts = ParserOptions::newFromUser( $popts );
+		}
+
+		// Determine the options which affect this article
+		$casToken = null;
+		$optionsKey = $this->mMemc->get(
+			$this->getOptionsKey( $article ), $casToken, BagOStuff::READ_VERIFIED );
+		if ( $optionsKey instanceof CacheTime ) {
+			if ( $useOutdated < self::USE_EXPIRED && $optionsKey->expired( $article->getTouched() ) ) {
+				wfIncrStats( "pcache.miss.expired" );
+				$cacheTime = $optionsKey->getCacheTime();
+				wfDebugLog( "ParserCache",
+					"Parser options key expired, touched " . $article->getTouched()
+					. ", epoch {$this->cacheEpoch}, cached $cacheTime\n" );
+				return false;
+			} elseif ( $useOutdated < self::USE_OUTDATED &&
+				$optionsKey->isDifferentRevision( $article->getLatest() )
+			) {
+				wfIncrStats( "pcache.miss.revid" );
+				$revId = $article->getLatest();
+				$cachedRevId = $optionsKey->getCacheRevisionId();
+				wfDebugLog( "ParserCache",
+					"ParserOutput key is for an old revision, latest $revId, cached $cachedRevId\n"
+				);
+				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::USE_ANYTHING ) {
+				return false;
+			}
+			$usedOptions = ParserOptions::allCacheVaryingOptions();
+		}
+
+		return $this->getParserOutputKey(
+			$article,
+			$popts->optionsHash( $usedOptions, $article->getTitle() )
+		);
+	}
+
+	/**
+	 * Retrieve the ParserOutput from ParserCache.
+	 * false if not found or outdated.
+	 *
+	 * @param WikiPage|Article $article
+	 * @param ParserOptions $popts
+	 * @param bool $useOutdated (default false)
+	 *
+	 * @return ParserOutput|bool False on failure
+	 */
+	public function get( $article, $popts, $useOutdated = false ) {
+		$canCache = $article->checkTouched();
+		if ( !$canCache ) {
+			// It's a redirect now
+			return false;
+		}
+
+		$touched = $article->getTouched();
+
+		$parserOutputKey = $this->getKey( $article, $popts,
+			$useOutdated ? self::USE_OUTDATED : self::USE_CURRENT_ONLY
+		);
+		if ( $parserOutputKey === false ) {
+			wfIncrStats( 'pcache.miss.absent' );
+			return false;
+		}
+
+		$casToken = null;
+		/** @var ParserOutput $value */
+		$value = $this->mMemc->get( $parserOutputKey, $casToken, BagOStuff::READ_VERIFIED );
+		if ( !$value ) {
+			wfDebug( "ParserOutput cache miss.\n" );
+			wfIncrStats( "pcache.miss.absent" );
+			return false;
+		}
+
+		wfDebug( "ParserOutput cache found.\n" );
+
+		$wikiPage = method_exists( $article, 'getPage' )
+			? $article->getPage()
+			: $article;
+
+		if ( !$useOutdated && $value->expired( $touched ) ) {
+			wfIncrStats( "pcache.miss.expired" );
+			$cacheTime = $value->getCacheTime();
+			wfDebugLog( "ParserCache",
+				"ParserOutput key expired, touched $touched, "
+				. "epoch {$this->cacheEpoch}, cached $cacheTime\n" );
+			$value = false;
+		} elseif ( !$useOutdated && $value->isDifferentRevision( $article->getLatest() ) ) {
+			wfIncrStats( "pcache.miss.revid" );
+			$revId = $article->getLatest();
+			$cachedRevId = $value->getCacheRevisionId();
+			wfDebugLog( "ParserCache",
+				"ParserOutput key is for an old revision, latest $revId, cached $cachedRevId\n"
+			);
+			$value = false;
+		} elseif (
+			Hooks::run( 'RejectParserCacheValue', [ $value, $wikiPage, $popts ] ) === false
+		) {
+			wfIncrStats( 'pcache.miss.rejected' );
+			wfDebugLog( "ParserCache",
+				"ParserOutput key valid, but rejected by RejectParserCacheValue hook handler.\n"
+			);
+			$value = false;
+		} else {
+			wfIncrStats( "pcache.hit" );
+		}
+
+		return $value;
+	}
+
+	/**
+	 * @param ParserOutput $parserOutput
+	 * @param WikiPage $page
+	 * @param ParserOptions $popts
+	 * @param string $cacheTime Time when the cache was generated
+	 * @param int $revId Revision ID that was parsed
+	 */
+	public function save( $parserOutput, $page, $popts, $cacheTime = null, $revId = null ) {
+		$expire = $parserOutput->getCacheExpiry();
+		if ( $expire > 0 && !$this->mMemc instanceof EmptyBagOStuff ) {
+			$cacheTime = $cacheTime ?: wfTimestampNow();
+			if ( !$revId ) {
+				$revision = $page->getRevision();
+				$revId = $revision ? $revision->getId() : null;
+			}
+
+			$optionsKey = new CacheTime;
+			$optionsKey->mUsedOptions = $parserOutput->getUsedOptions();
+			$optionsKey->updateCacheExpiry( $expire );
+
+			$optionsKey->setCacheTime( $cacheTime );
+			$parserOutput->setCacheTime( $cacheTime );
+			$optionsKey->setCacheRevisionId( $revId );
+			$parserOutput->setCacheRevisionId( $revId );
+
+			$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( $page->getTimestamp() );
+
+			$msg = "Saved in parser cache with key $parserOutputKey" .
+				" and timestamp $cacheTime" .
+				" and revision id $revId" .
+				"\n";
+
+			$parserOutput->mText .= "\n<!-- $msg -->\n";
+			wfDebug( $msg );
+
+			// Save the parser output
+			$this->mMemc->set( $parserOutputKey, $parserOutput, $expire );
+
+			// ...and its pointer
+			$this->mMemc->set( $this->getOptionsKey( $page ), $optionsKey, $expire );
+
+			Hooks::run(
+				'ParserCacheSaveComplete',
+				[ $this, $parserOutput, $page->getTitle(), $popts, $revId ]
+			);
+		} elseif ( $expire <= 0 ) {
+			wfDebug( "Parser output was marked as uncacheable and has not been saved.\n" );
+		}
+	}
+
+	/**
+	 * Get the backend BagOStuff instance that
+	 * powers the parser cache
+	 *
+	 * @since 1.30
+	 * @return BagOStuff
+	 */
+	public function getCacheStorage() {
+		return $this->mMemc;
+	}
+}