includes/parser/CacheTime.php
<?php
/**
* Parser cache specific expiry check.
*
* 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 Parser
*/
use MediaWiki\Json\JsonUnserializable;
use MediaWiki\Json\JsonUnserializableTrait;
use MediaWiki\Json\JsonUnserializer;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Parser\ParserCacheMetadata;
use MediaWiki\Utils\MWTimestamp;
use Wikimedia\Reflection\GhostFieldAccessTrait;
/**
* Parser cache specific expiry check.
*
* @ingroup Parser
*/
class CacheTime implements ParserCacheMetadata, JsonUnserializable {
use GhostFieldAccessTrait;
use JsonUnserializableTrait;
/**
* @var true[] ParserOptions which have been taken into account
* to produce output, option names stored in array keys.
*/
protected $mParseUsedOptions = [];
/**
* @var string|int TS_MW timestamp when this object was generated, or -1 for not cacheable. Used
* in ParserCache.
*/
protected $mCacheTime = '';
/**
* @var int|null Seconds after which the object should expire, use 0 for not cacheable. Used in
* ParserCache.
*/
protected $mCacheExpiry = null;
/**
* @var int|null Revision ID that was parsed
*/
protected $mCacheRevisionId = null;
/**
* @return string|int TS_MW timestamp
*/
public function getCacheTime() {
// NOTE: keep support for undocumented used of -1 to mean "not cacheable".
if ( $this->mCacheTime === '' ) {
$this->mCacheTime = MWTimestamp::now();
}
return $this->mCacheTime;
}
/**
* @return bool true if a cache time has been set
*/
public function hasCacheTime(): bool {
return $this->mCacheTime !== '';
}
/**
* setCacheTime() sets the timestamp expressing when the page has been rendered.
* This does not control expiry, see updateCacheExpiry() for that!
* @param string $t TS_MW timestamp
* @return string
*/
public function setCacheTime( $t ) {
// NOTE: keep support for undocumented used of -1 to mean "not cacheable".
if ( is_string( $t ) && $t !== '-1' ) {
$t = MWTimestamp::convert( TS_MW, $t );
}
if ( $t === -1 || $t === '-1' ) {
wfDeprecatedMsg( __METHOD__ . ' called with -1 as an argument', '1.36' );
}
return wfSetVar( $this->mCacheTime, $t );
}
/**
* @since 1.23
* @return int|null Revision id, if any was set
*/
public function getCacheRevisionId(): ?int {
return $this->mCacheRevisionId;
}
/**
* @since 1.23
* @param int|null $id Revision ID
*/
public function setCacheRevisionId( $id ) {
$this->mCacheRevisionId = $id;
}
/**
* Sets the number of seconds after which this object should expire.
*
* This value is used with the ParserCache.
* If called with a value greater than the value provided at any previous call,
* the new call has no effect. The value returned by getCacheExpiry is smaller
* or equal to the smallest number that was provided as an argument to
* updateCacheExpiry().
*
* Avoid using 0 if at all possible. Consider JavaScript for highly dynamic content.
*
* NOTE: Beware that reducing the TTL for reasons that do not relate to "dynamic content",
* may have the side-effect of incurring more RefreshLinksJob executions.
* See also WikiPage::triggerOpportunisticLinksUpdate.
*
* @param int $seconds
*/
public function updateCacheExpiry( $seconds ) {
$seconds = (int)$seconds;
if ( $this->mCacheExpiry === null || $this->mCacheExpiry > $seconds ) {
$this->mCacheExpiry = $seconds;
}
}
/**
* Returns the number of seconds after which this object should expire.
* This method is used by ParserCache to determine how long the ParserOutput can be cached.
* The timestamp of expiry can be calculated by adding getCacheExpiry() to getCacheTime().
* The value returned by getCacheExpiry is smaller or equal to the smallest number
* that was provided to a call of updateCacheExpiry(), and smaller or equal to the
* value of $wgParserCacheExpireTime.
* @return int
*/
public function getCacheExpiry(): int {
$parserCacheExpireTime = MediaWikiServices::getInstance()->getMainConfig()
->get( MainConfigNames::ParserCacheExpireTime );
// NOTE: keep support for undocumented used of -1 to mean "not cacheable".
if ( $this->mCacheTime !== '' && $this->mCacheTime < 0 ) {
return 0;
}
$expire = min( $this->mCacheExpiry ?? $parserCacheExpireTime, $parserCacheExpireTime );
return $expire > 0 ? $expire : 0;
}
/**
* @return bool
*/
public function isCacheable() {
return $this->getCacheExpiry() > 0;
}
/**
* Return true if this cached output object predates the global or
* per-article cache invalidation timestamps, or if it comes from
* an incompatible older version.
*
* @param string $touched The affected article's last touched timestamp
* @return bool
*/
public function expired( $touched ) {
$cacheEpoch = MediaWikiServices::getInstance()->getMainConfig()->get( MainConfigNames::CacheEpoch );
$expiry = MWTimestamp::convert( TS_MW, MWTimestamp::time() - $this->getCacheExpiry() );
return !$this->isCacheable() // parser says it's not cacheable
|| $this->getCacheTime() < $touched
|| $this->getCacheTime() <= $cacheEpoch
|| $this->getCacheTime() < $expiry; // expiry period has passed
}
/**
* Return true if this cached output object is for a different revision of
* the page.
*
* @todo We always return false if $this->getCacheRevisionId() is null;
* this prevents invalidating the whole parser cache when this change is
* deployed. Someday that should probably be changed.
*
* @since 1.23
* @param int $id The affected article's current revision id
* @return bool
*/
public function isDifferentRevision( $id ) {
$cached = $this->getCacheRevisionId();
return $cached !== null && $id !== $cached;
}
/**
* Returns the options from its ParserOptions which have been taken
* into account to produce the output.
* @since 1.36
* @return string[]
*/
public function getUsedOptions(): array {
return array_keys( $this->mParseUsedOptions );
}
/**
* Tags a parser option for use in the cache key for this parser output.
* Registered as a watcher at ParserOptions::registerWatcher() by Parser::clearState().
* The information gathered here is available via getUsedOptions(),
* and is used by ParserCache::save().
*
* @see ParserCache::getMetadata
* @see ParserCache::save
* @see ParserOptions::addExtraKey
* @see ParserOptions::optionsHash
* @param string $option
*/
public function recordOption( string $option ) {
$this->mParseUsedOptions[$option] = true;
}
/**
* Tags a list of parser option names for use in the cache key for this parser output.
*
* @see recordOption()
* @param string[] $options
*/
public function recordOptions( array $options ) {
$this->mParseUsedOptions = array_merge(
$this->mParseUsedOptions,
array_fill_keys( $options, true )
);
}
/**
* Returns a JSON serializable structure representing this CacheTime instance.
* @see newFromJson()
*
* @return array
*/
protected function toJsonArray(): array {
// WARNING: When changing how this class is serialized, follow the instructions
// at <https://www.mediawiki.org/wiki/Manual:Parser_cache/Serialization_compatibility>!
return [
'ParseUsedOptions' => $this->mParseUsedOptions,
'CacheExpiry' => $this->mCacheExpiry,
'CacheTime' => $this->mCacheTime,
'CacheRevisionId' => $this->mCacheRevisionId,
];
}
public static function newFromJsonArray( JsonUnserializer $unserializer, array $json ) {
$cacheTime = new CacheTime();
$cacheTime->initFromJson( $unserializer, $json );
return $cacheTime;
}
/**
* Initialize member fields from an array returned by jsonSerialize().
* @param JsonUnserializer $unserializer
* @param array $jsonData
*/
protected function initFromJson( JsonUnserializer $unserializer, array $jsonData ) {
// WARNING: When changing how this class is serialized, follow the instructions
// at <https://www.mediawiki.org/wiki/Manual:Parser_cache/Serialization_compatibility>!
if ( array_key_exists( 'AccessedOptions', $jsonData ) ) {
// Backwards compatibility for ParserOutput
$this->mParseUsedOptions = $jsonData['AccessedOptions'] ?: [];
} elseif ( array_key_exists( 'UsedOptions', $jsonData ) ) {
// Backwards compatibility
$this->recordOptions( $jsonData['UsedOptions'] ?: [] );
} else {
$this->mParseUsedOptions = $jsonData['ParseUsedOptions'] ?: [];
}
$this->mCacheExpiry = $jsonData['CacheExpiry'];
$this->mCacheTime = $jsonData['CacheTime'];
$this->mCacheRevisionId = $jsonData['CacheRevisionId'];
}
public function __wakeup() {
// Backwards compatibility, pre 1.36
$priorOptions = $this->getGhostFieldValue( 'mUsedOptions' );
if ( $priorOptions ) {
$this->recordOptions( $priorOptions );
}
}
public function __get( $name ) {
if ( property_exists( get_called_class(), $name ) ) {
// Direct access to a public property, deprecated.
wfDeprecatedMsg( "CacheTime::{$name} public read access deprecated", '1.38' );
return $this->$name;
} elseif ( property_exists( $this, $name ) ) {
// Dynamic property access, deprecated.
wfDeprecatedMsg( "CacheTime::{$name} dynamic property read access deprecated", '1.38' );
return $this->$name;
} else {
trigger_error( "Inaccessible property via __set(): $name" );
return null;
}
}
public function __set( $name, $value ) {
if ( property_exists( get_called_class(), $name ) ) {
// Direct access to a public property, deprecated.
wfDeprecatedMsg( "CacheTime::$name public write access deprecated", '1.38' );
$this->$name = $value;
} else {
// Dynamic property access, deprecated.
wfDeprecatedMsg( "CacheTime::$name dynamic property write access deprecated", '1.38' );
$this->$name = $value;
}
}
}