apc.php

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<?php
/**
 * @package     Joomla.Platform
 * @subpackage  Cache
 *
 * @copyright   Copyright (C) 2005 - 2013 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE
 */

defined('JPATH_PLATFORM') or die;

/**
 * APC cache storage handler
 *
 * @package     Joomla.Platform
 * @subpackage  Cache
 * @see         http://php.net/manual/en/book.apc.php
 * @since       11.1
 */
class JCacheStorageApc extends JCacheStorage
{
        /**
         * Get cached data from APC by id and group
         *
         * @param   string   $id         The cache data id
         * @param   string   $group      The cache data group
         * @param   boolean  $checkTime  True to verify cache time expiration threshold
         *
         * @return  mixed    Boolean     False on failure or a cached data string
         *
         * @since   11.1
         */
        public function get($id, $group, $checkTime = true)
        {
                $cache_id = $this->_getCacheId($id, $group);
                return apc_fetch($cache_id);
        }

        /**
         * Get all cached data
         *
         * @return  array  data
         *
         * @since   11.1
         */
        public function getAll()
        {
                parent::getAll();

                $allinfo = apc_cache_info('user');
                $keys = $allinfo['cache_list'];
                $secret = $this->_hash;

                $data = array();

                foreach ($keys as $key)
                {

                        $name = $key['info'];
                        $namearr = explode('-', $name);

                        if ($namearr !== false && $namearr[0] == $secret && $namearr[1] == 'cache')
                        {
                                $group = $namearr[2];

                                if (!isset($data[$group]))
                                {
                                        $item = new JCacheStorageHelper($group);
                                }
                                else
                                {
                                        $item = $data[$group];
                                }

                                $item->updateSize($key['mem_size'] / 1024);

                                $data[$group] = $item;
                        }
                }

                return $data;
        }

        /**
         * Store the data to APC by id and group
         *
         * @param   string  $id     The cache data id
         * @param   string  $group  The cache data group
         * @param   string  $data   The data to store in cache
         *
         * @return  boolean  True on success, false otherwise
         *
         * @since   11.1
         */
        public function store($id, $group, $data)
        {
                $cache_id = $this->_getCacheId($id, $group);
                return apc_store($cache_id, $data, $this->_lifetime);
        }

        /**
         * Remove a cached data entry by id and group
         *
         * @param   string  $id     The cache data id
         * @param   string  $group  The cache data group
         *
         * @return  boolean  True on success, false otherwise
         *
         * @since   11.1
         */
        public function remove($id, $group)
        {
                $cache_id = $this->_getCacheId($id, $group);
                return apc_delete($cache_id);
        }

        /**
         * Clean cache for a group given a mode.
         *
         * group mode    : cleans all cache in the group
         * notgroup mode : cleans all cache not in the group
         *
         * @param   string  $group  The cache data group
         * @param   string  $mode   The mode for cleaning cache [group|notgroup]
         *
         * @return  boolean  True on success, false otherwise
         *
         * @since   11.1
         */
        public function clean($group, $mode = null)
        {
                $allinfo = apc_cache_info('user');
                $keys = $allinfo['cache_list'];
                $secret = $this->_hash;

                foreach ($keys as $key)
                {

                        if (strpos($key['info'], $secret . '-cache-' . $group . '-') === 0 xor $mode != 'group')
                        {
                                apc_delete($key['info']);
                        }
                }
                return true;
        }

        /**
         * Force garbage collect expired cache data as items are removed only on fetch!
         *
         * @return  boolean  True on success, false otherwise.
         *
         * @since   11.1
         */
        public function gc()
        {
                $allinfo = apc_cache_info('user');
                $keys = $allinfo['cache_list'];
                $secret = $this->_hash;

                foreach ($keys as $key)
                {
                        if (strpos($key['info'], $secret . '-cache-'))
                        {
                                apc_fetch($key['info']);
                        }
                }
        }

        /**
         * Test to see if the cache storage is available.
         *
         * @return  boolean  True on success, false otherwise.
         *
         * @since   12.1
         */
        public static function isSupported()
        {
                return extension_loaded('apc');
        }

        /**
         * Lock cached item - override parent as this is more efficient
         *
         * @param   string   $id        The cache data id
         * @param   string   $group     The cache data group
         * @param   integer  $locktime  Cached item max lock time
         *
         * @return  object   Properties are lock and locklooped
         *
         * @since   11.1
         */
        public function lock($id, $group, $locktime)
        {
                $returning = new stdClass;
                $returning->locklooped = false;

                $looptime = $locktime * 10;

                $cache_id = $this->_getCacheId($id, $group) . '_lock';

                $data_lock = apc_add($cache_id, 1, $locktime);

                if ($data_lock === false)
                {

                        $lock_counter = 0;

                        // Loop until you find that the lock has been released.
                        // That implies that data get from other thread has finished
                        while ($data_lock === false)
                        {

                                if ($lock_counter > $looptime)
                                {
                                        $returning->locked = false;
                                        $returning->locklooped = true;
                                        break;
                                }

                                usleep(100);
                                $data_lock = apc_add($cache_id, 1, $locktime);
                                $lock_counter++;
                        }

                }
                $returning->locked = $data_lock;

                return $returning;
        }

        /**
         * Unlock cached item - override parent for cacheid compatibility with lock
         *
         * @param   string  $id     The cache data id
         * @param   string  $group  The cache data group
         *
         * @return  boolean  True on success, false otherwise.
         *
         * @since   11.1
         */
        public function unlock($id, $group = null)
        {
                $cache_id = $this->_getCacheId($id, $group) . '_lock';

                $unlock = apc_delete($cache_id);
                return $unlock;
        }
}