Memcached.php

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<?php
#require_once 'Zend/Cache/Backend/ExtendedInterface.php';

#require_once 'Zend/Cache/Backend.php';


class Zend_Cache_Backend_Memcached extends Zend_Cache_Backend implements Zend_Cache_Backend_ExtendedInterface
{
    const DEFAULT_HOST = '127.0.0.1';
    const DEFAULT_PORT =  11211;
    const DEFAULT_PERSISTENT = true;
    const DEFAULT_WEIGHT  = 1;
    const DEFAULT_TIMEOUT = 1;
    const DEFAULT_RETRY_INTERVAL = 15;
    const DEFAULT_STATUS = true;
    const DEFAULT_FAILURE_CALLBACK = null;

    const TAGS_UNSUPPORTED_BY_CLEAN_OF_MEMCACHED_BACKEND = 'Zend_Cache_Backend_Memcached::clean() : tags are unsupported by the Memcached backend';
    const TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND =  'Zend_Cache_Backend_Memcached::save() : tags are unsupported by the Memcached backend';

    protected $_options = array(
        'servers' => array(array(
            'host' => self::DEFAULT_HOST,
            'port' => self::DEFAULT_PORT,
            'persistent' => self::DEFAULT_PERSISTENT,
            'weight'  => self::DEFAULT_WEIGHT,
            'timeout' => self::DEFAULT_TIMEOUT,
            'retry_interval' => self::DEFAULT_RETRY_INTERVAL,
            'status' => self::DEFAULT_STATUS,
            'failure_callback' => self::DEFAULT_FAILURE_CALLBACK
        )),
        'compression' => false,
        'compatibility' => false,
    );

    protected $_memcache = null;

    public function __construct(array $options = array())
    {
        if (!extension_loaded('memcache')) {
            Zend_Cache::throwException('The memcache extension must be loaded for using this backend !');
        }
        parent::__construct($options);
        if (isset($this->_options['servers'])) {
            $value= $this->_options['servers'];
            if (isset($value['host'])) {
                // in this case, $value seems to be a simple associative array (one server only)
                $value = array(0 => $value); // let's transform it into a classical array of associative arrays
            }
            $this->setOption('servers', $value);
        }
        $this->_memcache = new Memcache;
        foreach ($this->_options['servers'] as $server) {
            if (!array_key_exists('port', $server)) {
                $server['port'] = self::DEFAULT_PORT;
            }
            if (!array_key_exists('persistent', $server)) {
                $server['persistent'] = self::DEFAULT_PERSISTENT;
            }
            if (!array_key_exists('weight', $server)) {
                $server['weight'] = self::DEFAULT_WEIGHT;
            }
            if (!array_key_exists('timeout', $server)) {
                $server['timeout'] = self::DEFAULT_TIMEOUT;
            }
            if (!array_key_exists('retry_interval', $server)) {
                $server['retry_interval'] = self::DEFAULT_RETRY_INTERVAL;
            }
            if (!array_key_exists('status', $server)) {
                $server['status'] = self::DEFAULT_STATUS;
            }
            if (!array_key_exists('failure_callback', $server)) {
                $server['failure_callback'] = self::DEFAULT_FAILURE_CALLBACK;
            }
            if ($this->_options['compatibility']) {
                // No status for compatibility mode (#ZF-5887)
                $this->_memcache->addServer($server['host'], $server['port'], $server['persistent'],
                                        $server['weight'], $server['timeout'],
                                        $server['retry_interval']);
            } else {
                $this->_memcache->addServer($server['host'], $server['port'], $server['persistent'],
                                        $server['weight'], $server['timeout'],
                                        $server['retry_interval'],
                                        $server['status'], $server['failure_callback']);
            }
        }
    }

    public function load($id, $doNotTestCacheValidity = false)
    {
        $tmp = $this->_memcache->get($id);
        if (is_array($tmp) && isset($tmp[0])) {
            return $tmp[0];
        }
        return false;
    }

    public function test($id)
    {
        $tmp = $this->_memcache->get($id);
        if (is_array($tmp)) {
            return $tmp[1];
        }
        return false;
    }

    public function save($data, $id, $tags = array(), $specificLifetime = false)
    {
        $lifetime = $this->getLifetime($specificLifetime);
        if ($this->_options['compression']) {
            $flag = MEMCACHE_COMPRESSED;
        } else {
            $flag = 0;
        }

        // ZF-8856: using set because add needs a second request if item already exists
        $result = @$this->_memcache->set($id, array($data, time(), $lifetime), $flag, $lifetime);

        if (count($tags) > 0) {
            $this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND);
        }

        return $result;
    }

    public function remove($id)
    {
        return $this->_memcache->delete($id, 0);
    }

    public function clean($mode = Zend_Cache::CLEANING_MODE_ALL, $tags = array())
    {
        switch ($mode) {
            case Zend_Cache::CLEANING_MODE_ALL:
                return $this->_memcache->flush();
                break;
            case Zend_Cache::CLEANING_MODE_OLD:
                $this->_log("Zend_Cache_Backend_Memcached::clean() : CLEANING_MODE_OLD is unsupported by the Memcached backend");
                break;
            case Zend_Cache::CLEANING_MODE_MATCHING_TAG:
            case Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG:
            case Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG:
                $this->_log(self::TAGS_UNSUPPORTED_BY_CLEAN_OF_MEMCACHED_BACKEND);
                break;
               default:
                Zend_Cache::throwException('Invalid mode for clean() method');
                   break;
        }
    }

    public function isAutomaticCleaningAvailable()
    {
        return false;
    }

    public function setDirectives($directives)
    {
        parent::setDirectives($directives);
        $lifetime = $this->getLifetime(false);
        if ($lifetime > 2592000) {
            // #ZF-3490 : For the memcached backend, there is a lifetime limit of 30 days (2592000 seconds)
            $this->_log('memcached backend has a limit of 30 days (2592000 seconds) for the lifetime');
        }
        if ($lifetime === null) {
            // #ZF-4614 : we tranform null to zero to get the maximal lifetime
            parent::setDirectives(array('lifetime' => 0));
        }
    }

    public function getIds()
    {
        $this->_log("Zend_Cache_Backend_Memcached::save() : getting the list of cache ids is unsupported by the Memcache backend");
        return array();
    }

    public function getTags()
    {
        $this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND);
        return array();
    }

    public function getIdsMatchingTags($tags = array())
    {
        $this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND);
        return array();
    }

    public function getIdsNotMatchingTags($tags = array())
    {
        $this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND);
        return array();
    }

    public function getIdsMatchingAnyTags($tags = array())
    {
        $this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND);
        return array();
    }

    public function getFillingPercentage()
    {
        $mems = $this->_memcache->getExtendedStats();

        $memSize = null;
        $memUsed = null;
        foreach ($mems as $key => $mem) {
            if ($mem === false) {
                $this->_log('can\'t get stat from ' . $key);
                continue;
            }

            $eachSize = $mem['limit_maxbytes'];

            $eachUsed = isset($mem['bytes']) ? $mem['bytes'] : $mem['mem_used'];
            if ($eachUsed > $eachSize) {
                $eachUsed = $eachSize;
            }

            $memSize += $eachSize;
            $memUsed += $eachUsed;
        }

        if ($memSize === null || $memUsed === null) {
            Zend_Cache::throwException('Can\'t get filling percentage');
        }

        return ((int) (100. * ($memUsed / $memSize)));
    }

    public function getMetadatas($id)
    {
        $tmp = $this->_memcache->get($id);
        if (is_array($tmp)) {
            $data = $tmp[0];
            $mtime = $tmp[1];
            if (!isset($tmp[2])) {
                // because this record is only with 1.7 release
                // if old cache records are still there...
                return false;
            }
            $lifetime = $tmp[2];
            return array(
                'expire' => $mtime + $lifetime,
                'tags' => array(),
                'mtime' => $mtime
            );
        }
        return false;
    }

    public function touch($id, $extraLifetime)
    {
        if ($this->_options['compression']) {
            $flag = MEMCACHE_COMPRESSED;
        } else {
            $flag = 0;
        }
        $tmp = $this->_memcache->get($id);
        if (is_array($tmp)) {
            $data = $tmp[0];
            $mtime = $tmp[1];
            if (!isset($tmp[2])) {
                // because this record is only with 1.7 release
                // if old cache records are still there...
                return false;
            }
            $lifetime = $tmp[2];
            $newLifetime = $lifetime - (time() - $mtime) + $extraLifetime;
            if ($newLifetime <=0) {
                return false;
            }
            // #ZF-5702 : we try replace() first becase set() seems to be slower
            if (!($result = $this->_memcache->replace($id, array($data, time(), $newLifetime), $flag, $newLifetime))) {
                $result = $this->_memcache->set($id, array($data, time(), $newLifetime), $flag, $newLifetime);
            }
            return $result;
        }
        return false;
    }

    public function getCapabilities()
    {
        return array(
            'automatic_cleaning' => false,
            'tags' => false,
            'expired_read' => false,
            'priority' => false,
            'infinite_lifetime' => false,
            'get_list' => false
        );
    }

}