class.t3lib_cache_backend_transientmemorybackend.php

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<?php
/***************************************************************
 *  Copyright notice
 *
 *  (c) 2009-2011 Ingo Renner <ingo@typo3.org>
 *  All rights reserved
 *
 *  This script is part of the TYPO3 project. The TYPO3 project 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.
 *
 *  The GNU General Public License can be found at
 *  http://www.gnu.org/copyleft/gpl.html.
 *
 *  This script 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.
 *
 *  This copyright notice MUST APPEAR in all copies of the script!
 ***************************************************************/


/**
 * A caching backend which stores cache entries during one script run.
 *
 * This file is a backport from FLOW3
 *
 * @package TYPO3
 * @subpackage t3lib_cache
 * @api
 * @version $Id: class.t3lib_cache_backend_transientmemorybackend.php 10121 2011-01-18 20:15:30Z ohader $
 */
class t3lib_cache_backend_TransientMemoryBackend extends t3lib_cache_backend_AbstractBackend {

    /**
     * @var array
     */
    protected $entries = array();

    /**
     * @var array
     */
    protected $tagsAndEntries = array();

    /**
     * Saves data in the cache.
     *
     * @param string $entryIdentifier An identifier for this specific cache entry
     * @param string $data The data to be stored
     * @param array $tags Tags to associate with this cache entry
     * @param integer $lifetime Lifetime of this cache entry in seconds. If NULL is specified, the default lifetime is used. "0" means unlimited liftime.
     * @return void
     * @throws t3lib_cache_Exception if no cache frontend has been set.
     * @author Robert Lemke <robert@typo3.org>
     */
    public function set($entryIdentifier, $data, array $tags = array(), $lifetime = NULL) {
        if (!$this->cache instanceof t3lib_cache_frontend_Frontend) {
            throw new t3lib_cache_Exception('No cache frontend has been set yet via setCache().', 1238244992);
        }
        if (!is_string($data)) {
            throw new t3lib_cache_exception_InvalidData('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1238244993);
        }
        $this->entries[$entryIdentifier] = $data;
        foreach ($tags as $tag) {
            $this->tagsAndEntries[$tag][$entryIdentifier] = TRUE;
        }
    }

    /**
     * Loads data from the cache.
     *
     * @param string $entryIdentifier An identifier which describes the cache entry to load
     * @return mixed The cache entry's content as a string or FALSE if the cache entry could not be loaded
     * @author Robert Lemke <robert@typo3.org>
     */
    public function get($entryIdentifier) {
        return (isset($this->entries[$entryIdentifier])) ? $this->entries[$entryIdentifier] : FALSE;
    }

    /**
     * Checks if a cache entry with the specified identifier exists.
     *
     * @param string $entryIdentifier An identifier specifying the cache entry
     * @return boolean TRUE if such an entry exists, FALSE if not
     * @author Robert Lemke <robert@typo3.org>
     */
    public function has($entryIdentifier) {
        return isset($this->entries[$entryIdentifier]);
    }

    /**
     * Removes all cache entries matching the specified identifier.
     *
     * @param string $entryIdentifier Specifies the cache entry to remove
     * @return boolean TRUE if the entry could be removed or FALSE if no entry was found
     * @author Robert Lemke <robert@typo3.org>
     */
    public function remove($entryIdentifier) {
        if (isset($this->entries[$entryIdentifier])) {
            unset($this->entries[$entryIdentifier]);
            foreach (array_keys($this->tagsAndEntries) as $tag) {
                if (isset($this->tagsAndEntries[$tag][$entryIdentifier])) {
                    unset ($this->tagsAndEntries[$tag][$entryIdentifier]);
                }
            }
            return TRUE;
        } else {
            return FALSE;
        }
    }

    /**
     * Finds and returns all cache entry identifiers which are tagged by the
     * specified tag.
     *
     * @param string $tag The tag to search for
     * @return array An array with identifiers of all matching entries. An empty array if no entries matched
     * @author Robert Lemke <robert@typo3.org>
     */
    public function findIdentifiersByTag($tag) {
        if (isset($this->tagsAndEntries[$tag])) {
            return array_keys($this->tagsAndEntries[$tag]);
        } else {
            return array();
        }
    }

    /**
     * Finds and returns all cache entry identifiers which are tagged by the
     * specified tags.
     * The asterisk ("*") is allowed as a wildcard at the beginning and the end
     * of a tag.
     *
     * @param array Array of tags to search for, the "*" wildcard is supported
     * @return array An array with identifiers of all matching entries. An empty array if no entries matched
     * @author  Ingo Renner <ingo@typo3.org>
     */
    public function findIdentifiersByTags(array $tags) {
        $taggedEntries = array();
        $foundEntries = array();

        foreach ($tags as $tag) {
            $taggedEntries[$tag] = $this->findIdentifiersByTag($tag);
        }

        $intersectedTaggedEntries = call_user_func_array('array_intersect', $taggedEntries);

        foreach ($intersectedTaggedEntries as $entryIdentifier) {
            $foundEntries[$entryIdentifier] = $entryIdentifier;
        }

        return $foundEntries;
    }

    /**
     * Removes all cache entries of this cache.
     *
     * @return void
     * @author Robert Lemke <robert@typo3.org>
     */
    public function flush() {
        $this->entries = array();
        $this->tagsAndEntries = array();
    }

    /**
     * Removes all cache entries of this cache which are tagged by the specified tag.
     *
     * @param string $tag The tag the entries must have
     * @return void
     * @author Robert Lemke <robert@typo3.org>
     */
    public function flushByTag($tag) {
        $identifiers = $this->findIdentifiersByTag($tag);
        foreach ($identifiers as $identifier) {
            $this->remove($identifier);
        }
    }

    /**
     * Removes all cache entries of this cache which are tagged by the specified tags.
     *
     * @param   array   The tags the entries must have
     * @return void
     * @author  Ingo Renner <ingo@typo3.org>
     */
    public function flushByTags(array $tags) {
        foreach ($tags as $tag) {
            $this->flushByTag($tag);
        }
    }

    /**
     * Does nothing
     *
     * @return void
     * @author Robert Lemke <robert@typo3.org>
     */
    public function collectGarbage() {
    }
}


if (defined('TYPO3_MODE') && isset($GLOBALS['TYPO3_CONF_VARS'][TYPO3_MODE]['XCLASS']['t3lib/cache/backend/class.t3lib_cache_backend_transientmemorybackend.php'])) {
    include_once($GLOBALS['TYPO3_CONF_VARS'][TYPO3_MODE]['XCLASS']['t3lib/cache/backend/class.t3lib_cache_backend_transientmemorybackend.php']);
}

?>