Current File : //www/varak.net/wiki.varak.net/includes/parser/ParserCache.php
<?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|null $cacheTime TS_MW timestamp when the cache was generated
* @param int|null $revId Revision ID that was parsed
*/
public function save(
ParserOutput $parserOutput,
$page,
$popts,
$cacheTime = null,
$revId = null
) {
if ( !$parserOutput->hasText() ) {
throw new InvalidArgumentException( 'Attempt to cache a ParserOutput with no text set!' );
}
$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;
}
}
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