<?php

/**

 * Zend Framework

 *

 * LICENSE

 *

 * This source file is subject to the new BSD license that is bundled

 * with this package in the file LICENSE.txt.

 * It is also available through the world-wide-web at this URL:

 * http://framework.zend.com/license/new-bsd

 * If you did not receive a copy of the license and are unable to

 * obtain it through the world-wide-web, please send an email

 * to license@zend.com so we can send you a copy immediately.

 *

 * @category   Zend

 * @package    Zend_Cache

 * @subpackage Zend_Cache_Backend

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 */

/**

 * @see Zend_Cache_Backend_Interface

 */

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

/**

 * @see Zend_Cache_Backend

 */

require_once 'Zend/Cache/Backend.php';

/**

 * @package    Zend_Cache

 * @subpackage Zend_Cache_Backend

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 */

class Zend_Cache_Backend_Memcached extends Zend_Cache_Backend implements Zend_Cache_Backend_ExtendedInterface

{

    /**

     * Default Values

     */

    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;

    /**

     * Log message

     */

    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';

    /**

     * Available options

     *

     * =====> (array) servers :

     * an array of memcached server ; each memcached server is described by an associative array :

     * 'host' => (string) : the name of the memcached server

     * 'port' => (int) : the port of the memcached server

     * 'persistent' => (bool) : use or not persistent connections to this memcached server

     * 'weight' => (int) : number of buckets to create for this server which in turn control its

     *                     probability of it being selected. The probability is relative to the total

     *                     weight of all servers.

     * 'timeout' => (int) : value in seconds which will be used for connecting to the daemon. Think twice

     *                      before changing the default value of 1 second - you can lose all the

     *                      advantages of caching if your connection is too slow.

     * 'retry_interval' => (int) : controls how often a failed server will be retried, the default value

     *                             is 15 seconds. Setting this parameter to -1 disables automatic retry.

     * 'status' => (bool) : controls if the server should be flagged as online.

     * 'failure_callback' => (callback) : Allows the user to specify a callback function to run upon

     *                                    encountering an error. The callback is run before failover

     *                                    is attempted. The function takes two parameters, the hostname

     *                                    and port of the failed server.

     *

     * =====> (boolean) compression :

     * true if you want to use on-the-fly compression

     *

     * =====> (boolean) compatibility :

     * true if you use old memcache server or extension

     *

     * @var array available options

     */

    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,

    );

    /**

     * Memcache object

     *

     * @var mixed memcache object

     */

    protected $_memcache = null;

    /**

     * Constructor

     *

     * @param array $options associative array of options

     * @throws Zend_Cache_Exception

     * @return void

     */

    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']);

            }

        }

    }

    /**

     * Test if a cache is available for the given id and (if yes) return it (false else)

     *

     * @param  string  $id                     Cache id

     * @param  boolean $doNotTestCacheValidity If set to true, the cache validity won't be tested

     * @return string|false cached datas

     */

    public function load($id, $doNotTestCacheValidity = false)

    {

        $tmp = $this->_memcache->get($id);

        if (is_array($tmp) && isset($tmp[0])) {

            return $tmp[0];

        }

        return false;

    }

    /**

     * Test if a cache is available or not (for the given id)

     *

     * @param  string $id Cache id

     * @return mixed|false (a cache is not available) or "last modified" timestamp (int) of the available cache record

     */

    public function test($id)

    {

        $tmp = $this->_memcache->get($id);

        if (is_array($tmp)) {

            return $tmp[1];

        }

        return false;

    }

    /**

     * Save some string datas into a cache record

     *

     * Note : $data is always "string" (serialization is done by the

     * core not by the backend)

     *

     * @param  string $data             Datas to cache

     * @param  string $id               Cache id

     * @param  array  $tags             Array of strings, the cache record will be tagged by each string entry

     * @param  int    $specificLifetime If != false, set a specific lifetime for this cache record (null => infinite lifetime)

     * @return boolean True if no problem

     */

    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;

    }

    /**

     * Remove a cache record

     *

     * @param  string $id Cache id

     * @return boolean True if no problem

     */

    public function remove($id)

    {

        return $this->_memcache->delete($id, 0);

    }

    /**

     * Clean some cache records

     *

     * Available modes are :

     * 'all' (default)  => remove all cache entries ($tags is not used)

     * 'old'            => unsupported

     * 'matchingTag'    => unsupported

     * 'notMatchingTag' => unsupported

     * 'matchingAnyTag' => unsupported

     *

     * @param  string $mode Clean mode

     * @param  array  $tags Array of tags

     * @throws Zend_Cache_Exception

     * @return boolean True if no problem

     */

    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;

        }

    }

    /**

     * Return true if the automatic cleaning is available for the backend

     *

     * @return boolean

     */

    public function isAutomaticCleaningAvailable()

    {

        return false;

    }

    /**

     * Set the frontend directives

     *

     * @param  array $directives Assoc of directives

     * @throws Zend_Cache_Exception

     * @return void

     */

    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));

        }

    }

    /**

     * Return an array of stored cache ids

     *

     * @return array array of stored cache ids (string)

     */

    public function getIds()

    {

        $this->_log("Zend_Cache_Backend_Memcached::save() : getting the list of cache ids is unsupported by the Memcache backend");

        return array();

    }

    /**

     * Return an array of stored tags

     *

     * @return array array of stored tags (string)

     */

    public function getTags()

    {

        $this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND);

        return array();

    }

    /**

     * Return an array of stored cache ids which match given tags

     *

     * In case of multiple tags, a logical AND is made between tags

     *

     * @param array $tags array of tags

     * @return array array of matching cache ids (string)

     */

    public function getIdsMatchingTags($tags = array())

    {

        $this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND);

        return array();

    }

    /**

     * Return an array of stored cache ids which don't match given tags

     *

     * In case of multiple tags, a logical OR is made between tags

     *

     * @param array $tags array of tags

     * @return array array of not matching cache ids (string)

     */

    public function getIdsNotMatchingTags($tags = array())

    {

        $this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND);

        return array();

    }

    /**

     * Return an array of stored cache ids which match any given tags

     *

     * In case of multiple tags, a logical AND is made between tags

     *

     * @param array $tags array of tags

     * @return array array of any matching cache ids (string)

     */

    public function getIdsMatchingAnyTags($tags = array())

    {

        $this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND);

        return array();

    }

    /**

     * Return the filling percentage of the backend storage

     *

     * @throws Zend_Cache_Exception

     * @return int integer between 0 and 100

     */

    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 = $mem['bytes'];

            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)));

    }

    /**

     * Return an array of metadatas for the given cache id

     *

     * The array must include these keys :

     * - expire : the expire timestamp

     * - tags : a string array of tags

     * - mtime : timestamp of last modification time

     *

     * @param string $id cache id

     * @return array array of metadatas (false if the cache id is not found)

     */

    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;

    }

    /**

     * Give (if possible) an extra lifetime to the given cache id

     *