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<?php |
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/** |
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* Cache of various elements in a single cache entry. |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License along |
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* with this program; if not, write to the Free Software Foundation, Inc., |
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
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* http://www.gnu.org/copyleft/gpl.html |
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* |
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* @file |
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* @license GNU GPL v2 or later |
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* @author Jeroen De Dauw < [email protected] > |
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*/ |
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/** |
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* Interface for all classes implementing CacheHelper functionality. |
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* |
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* @since 1.20 |
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*/ |
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interface ICacheHelper { |
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/** |
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* Sets if the cache should be enabled or not. |
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* |
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* @since 1.20 |
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* @param bool $cacheEnabled |
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*/ |
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function setCacheEnabled( $cacheEnabled ); |
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/** |
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* Initializes the caching. |
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* Should be called before the first time anything is added via addCachedHTML. |
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* |
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* @since 1.20 |
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* |
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* @param int|null $cacheExpiry Sets the cache expiry, either ttl in seconds or unix timestamp. |
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* @param bool|null $cacheEnabled Sets if the cache should be enabled or not. |
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*/ |
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function startCache( $cacheExpiry = null, $cacheEnabled = null ); |
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/** |
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* Get a cached value if available or compute it if not and then cache it if possible. |
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* The provided $computeFunction is only called when the computation needs to happen |
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* and should return a result value. $args are arguments that will be passed to the |
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* compute function when called. |
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* |
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* @since 1.20 |
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* |
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* @param callable $computeFunction |
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* @param array|mixed $args |
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* @param string|null $key |
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* |
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* @return mixed |
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*/ |
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function getCachedValue( $computeFunction, $args = [], $key = null ); |
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/** |
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* Saves the HTML to the cache in case it got recomputed. |
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* Should be called after the last time anything is added via addCachedHTML. |
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* |
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* @since 1.20 |
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*/ |
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function saveCache(); |
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/** |
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* Sets the time to live for the cache, in seconds or a unix timestamp |
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* indicating the point of expiry... |
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* |
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* @since 1.20 |
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* |
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* @param int $cacheExpiry |
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*/ |
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function setExpiry( $cacheExpiry ); |
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} |
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/** |
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* Helper class for caching various elements in a single cache entry. |
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* |
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* To get a cached value or compute it, use getCachedValue like this: |
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* $this->getCachedValue( $callback ); |
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* |
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* To add HTML that should be cached, use addCachedHTML like this: |
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* $this->addCachedHTML( $callback ); |
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* |
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* The callback function is only called when needed, so do all your expensive |
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* computations here. This function should returns the HTML to be cached. |
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* It should not add anything to the PageOutput object! |
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* |
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* Before the first addCachedHTML call, you should call $this->startCache(); |
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* After adding the last HTML that should be cached, call $this->saveCache(); |
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* |
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* @since 1.20 |
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*/ |
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class CacheHelper implements ICacheHelper { |
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/** |
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* The time to live for the cache, in seconds or a unix timestamp indicating the point of expiry. |
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* |
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* @since 1.20 |
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* @var int |
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*/ |
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protected $cacheExpiry = 3600; |
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/** |
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* List of HTML chunks to be cached (if !hasCached) or that where cached (of hasCached). |
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* If not cached already, then the newly computed chunks are added here, |
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* if it as cached already, chunks are removed from this list as they are needed. |
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* |
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* @since 1.20 |
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* @var array |
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*/ |
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protected $cachedChunks; |
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/** |
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* Indicates if the to be cached content was already cached. |
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* Null if this information is not available yet. |
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* |
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* @since 1.20 |
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* @var bool|null |
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*/ |
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protected $hasCached = null; |
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/** |
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* If the cache is enabled or not. |
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* |
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* @since 1.20 |
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* @var bool |
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*/ |
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protected $cacheEnabled = true; |
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/** |
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* Function that gets called when initialization is done. |
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* |
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* @since 1.20 |
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* @var callable |
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*/ |
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protected $onInitHandler = false; |
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/** |
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* Elements to build a cache key with. |
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* |
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* @since 1.20 |
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* @var array |
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*/ |
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protected $cacheKey = []; |
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/** |
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* Sets if the cache should be enabled or not. |
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* |
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* @since 1.20 |
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* @param bool $cacheEnabled |
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*/ |
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public function setCacheEnabled( $cacheEnabled ) { |
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$this->cacheEnabled = $cacheEnabled; |
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} |
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/** |
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* Initializes the caching. |
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* Should be called before the first time anything is added via addCachedHTML. |
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* |
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* @since 1.20 |
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* |
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* @param int|null $cacheExpiry Sets the cache expiry, either ttl in seconds or unix timestamp. |
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* @param bool|null $cacheEnabled Sets if the cache should be enabled or not. |
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*/ |
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public function startCache( $cacheExpiry = null, $cacheEnabled = null ) { |
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if ( is_null( $this->hasCached ) ) { |
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if ( !is_null( $cacheExpiry ) ) { |
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$this->cacheExpiry = $cacheExpiry; |
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} |
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if ( !is_null( $cacheEnabled ) ) { |
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$this->setCacheEnabled( $cacheEnabled ); |
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} |
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$this->initCaching(); |
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} |
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} |
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/** |
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* Returns a message that notifies the user he/she is looking at |
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* a cached version of the page, including a refresh link. |
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* |
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* @since 1.20 |
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* |
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* @param IContextSource $context |
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* @param bool $includePurgeLink |
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* |
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* @return string |
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*/ |
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public function getCachedNotice( IContextSource $context, $includePurgeLink = true ) { |
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if ( $this->cacheExpiry < 86400 * 3650 ) { |
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$message = $context->msg( |
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'cachedspecial-viewing-cached-ttl', |
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$context->getLanguage()->formatDuration( $this->cacheExpiry ) |
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)->escaped(); |
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} else { |
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$message = $context->msg( |
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'cachedspecial-viewing-cached-ts' |
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)->escaped(); |
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} |
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if ( $includePurgeLink ) { |
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$refreshArgs = $context->getRequest()->getQueryValues(); |
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unset( $refreshArgs['title'] ); |
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$refreshArgs['action'] = 'purge'; |
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$subPage = $context->getTitle()->getFullText(); |
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$subPage = explode( '/', $subPage, 2 ); |
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$subPage = count( $subPage ) > 1 ? $subPage[1] : false; |
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$message .= ' ' . Linker::link( |
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$context->getTitle( $subPage ), |
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$context->msg( 'cachedspecial-refresh-now' )->escaped(), |
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[], |
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$refreshArgs |
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); |
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} |
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return $message; |
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} |
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/** |
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* Initializes the caching if not already done so. |
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* Should be called before any of the caching functionality is used. |
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* |
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* @since 1.20 |
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*/ |
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protected function initCaching() { |
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if ( $this->cacheEnabled && is_null( $this->hasCached ) ) { |
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$cachedChunks = wfGetCache( CACHE_ANYTHING )->get( $this->getCacheKeyString() ); |
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$this->hasCached = is_array( $cachedChunks ); |
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$this->cachedChunks = $this->hasCached ? $cachedChunks : []; |
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if ( $this->onInitHandler !== false ) { |
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call_user_func( $this->onInitHandler, $this->hasCached ); |
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} |
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} |
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} |
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/** |
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* Get a cached value if available or compute it if not and then cache it if possible. |
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* The provided $computeFunction is only called when the computation needs to happen |
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* and should return a result value. $args are arguments that will be passed to the |
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* compute function when called. |
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* |
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* @since 1.20 |
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* |
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* @param callable $computeFunction |
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* @param array|mixed $args |
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* @param string|null $key |
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* |
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* @return mixed |
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*/ |
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public function getCachedValue( $computeFunction, $args = [], $key = null ) { |
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$this->initCaching(); |
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if ( $this->cacheEnabled && $this->hasCached ) { |
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$value = null; |
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if ( is_null( $key ) ) { |
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$itemKey = array_keys( array_slice( $this->cachedChunks, 0, 1 ) ); |
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$itemKey = array_shift( $itemKey ); |
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if ( !is_integer( $itemKey ) ) { |
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wfWarn( "Attempted to get item with non-numeric key while " . |
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"the next item in the queue has a key ($itemKey) in " . __METHOD__ ); |
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} elseif ( is_null( $itemKey ) ) { |
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wfWarn( "Attempted to get an item while the queue is empty in " . __METHOD__ ); |
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} else { |
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$value = array_shift( $this->cachedChunks ); |
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} |
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} else { |
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if ( array_key_exists( $key, $this->cachedChunks ) ) { |
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$value = $this->cachedChunks[$key]; |
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unset( $this->cachedChunks[$key] ); |
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} else { |
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wfWarn( "There is no item with key '$key' in this->cachedChunks in " . __METHOD__ ); |
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} |
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} |
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} else { |
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if ( !is_array( $args ) ) { |
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$args = [ $args ]; |
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} |
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$value = call_user_func_array( $computeFunction, $args ); |
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if ( $this->cacheEnabled ) { |
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if ( is_null( $key ) ) { |
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$this->cachedChunks[] = $value; |
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} else { |
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$this->cachedChunks[$key] = $value; |
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} |
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} |
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} |
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return $value; |
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} |
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/** |
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* Saves the HTML to the cache in case it got recomputed. |
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* Should be called after the last time anything is added via addCachedHTML. |
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* |
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* @since 1.20 |
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*/ |
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public function saveCache() { |
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if ( $this->cacheEnabled && $this->hasCached === false && !empty( $this->cachedChunks ) ) { |
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wfGetCache( CACHE_ANYTHING )->set( |
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$this->getCacheKeyString(), |
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$this->cachedChunks, |
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$this->cacheExpiry |
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); |
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} |
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} |
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/** |
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* Sets the time to live for the cache, in seconds or a unix timestamp |
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* indicating the point of expiry... |
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* |
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* @since 1.20 |
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* |
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* @param int $cacheExpiry |
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*/ |
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public function setExpiry( $cacheExpiry ) { |
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$this->cacheExpiry = $cacheExpiry; |
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} |
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/** |
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* Returns the cache key to use to cache this page's HTML output. |
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* Is constructed from the special page name and language code. |
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* |
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* @since 1.20 |
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* |
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* @return string |
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* @throws MWException |
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*/ |
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protected function getCacheKeyString() { |
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if ( $this->cacheKey === [] ) { |
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throw new MWException( 'No cache key set, so cannot obtain or save the CacheHelper values.' ); |
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} |
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return call_user_func_array( 'wfMemcKey', $this->cacheKey ); |
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} |
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/** |
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* Sets the cache key that should be used. |
356
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* |
357
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* @since 1.20 |
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* |
359
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* @param array $cacheKey |
360
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*/ |
361
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public function setCacheKey( array $cacheKey ) { |
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$this->cacheKey = $cacheKey; |
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} |
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|
365
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/** |
366
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* Rebuild the content, even if it's already cached. |
367
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* This effectively has the same effect as purging the cache, |
368
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* since it will be overridden with the new value on the next request. |
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* |
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* @since 1.20 |
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*/ |
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|
public function rebuildOnDemand() { |
373
|
|
|
$this->hasCached = false; |
374
|
|
|
} |
375
|
|
|
|
376
|
|
|
/** |
377
|
|
|
* Sets a function that gets called when initialization of the cache is done. |
378
|
|
|
* |
379
|
|
|
* @since 1.20 |
380
|
|
|
* |
381
|
|
|
* @param callable $handlerFunction |
382
|
|
|
*/ |
383
|
|
|
public function setOnInitializedHandler( $handlerFunction ) { |
384
|
|
|
$this->onInitHandler = $handlerFunction; |
385
|
|
|
} |
386
|
|
|
} |
387
|
|
|
|
Unless you are absolutely sure that the expression can never be null because of other conditions, we strongly recommend to add an additional type check to your code: