wikimedia/mediawiki-extensions-Wikibase

<?php

namespace Wikibase\Lib\Store;

use Wikibase\DataModel\Entity\EntityId;
use Wikimedia\ObjectCache\BagOStuff;

/**
 * Service for caching the latest EntityRevision of an Entity.
 *
 * @license GPL-2.0-or-later
 * @author Marius Hoch
 */
class EntityRevisionCache {

    /**
     * The cache to use for caching entities.
     *
     * @var BagOStuff
     */
    private $cache;

    /**
     * @var int
     */
    private $cacheTimeout;

    /**
     * The key prefix to use when caching entities in memory.
     *
     * @var string
     */
    private $cacheKeyPrefix;

    /**
     * @param BagOStuff $cache The cache to use
     * @param int $cacheDuration Cache duration in seconds. Defaults to 3600 (1 hour).
     * @param string $cacheKeyPrefix The key prefix to use for constructing cache keys.
     *         Defaults to "wbentity". There should be no reason to change this.
     */
    public function __construct(
        BagOStuff $cache,
        $cacheDuration = 3600,
        $cacheKeyPrefix = 'wbentity'
    ) {
        $this->cache = $cache;
        $this->cacheTimeout = $cacheDuration;
        $this->cacheKeyPrefix = $cacheKeyPrefix;
    }

    /**
     * Returns a cache key suitable for the given entity
     *
     * @param EntityId $entityId
     *
     * @return string
     */
    private function getCacheKey( EntityId $entityId ) {
        $cacheKey = $this->cacheKeyPrefix . ':' . $entityId->getSerialization();

        return $cacheKey;
    }

    /**
     * Get the latest EntityRevision from cache.
     * Note: This might return stale data!
     *
     * @param EntityId $entityId
     *
     * @return EntityRevision|null Null if the EntityRevision is not cached.
     */
    public function get( EntityId $entityId ) {
        $key = $this->getCacheKey( $entityId );
        $entityRevision = $this->cache->get( $key );

        if ( $entityRevision instanceof EntityRevision ) {
            return $entityRevision;
        }

        return null;
    }

    /**
     * Place the latest EntityRevision in the cache.
     *
     * @param EntityRevision $entityRevision
     */
    public function set( EntityRevision $entityRevision ) {
        $key = $this->getCacheKey( $entityRevision->getEntity()->getId() );
        $this->cache->set( $key, $entityRevision, $this->cacheTimeout );
    }

    /**
     * Removes an Entity's EntityRevision from the cache.
     *
     * @param EntityId $entityId
     */
    public function delete( EntityId $entityId ) {
        $key = $this->getCacheKey( $entityId );
        $this->cache->delete( $key );
    }

}