<?php

/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2019 - 2022, CodeIgniter Foundation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package CodeIgniter
 * @author  EllisLab Dev Team
 * @copyright   Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright   Copyright (c) 2014 - 2019, British Columbia Institute of Technology (https://bcit.ca/)
 * @copyright   Copyright (c) 2019 - 2022, CodeIgniter Foundation (https://codeigniter.com/)
 * @license https://opensource.org/licenses/MIT MIT License
 * @link    https://codeigniter.com
 * @since   Version 2.0
 * @filesource
 */

defined('BASEPATH') or exit('No direct script access allowed');

/**
 * CodeIgniter Memcached Caching Class
 *
 * @package     CodeIgniter
 * @subpackage  Libraries
 * @category    Core
 * @author      EllisLab Dev Team
 * @link
 */
class CI_Cache_memcached extends CI_Driver
{
    /**
     * Holds the memcached object
     *
     * @var object
     */
    protected $_memcached;

    /**
     * Memcached configuration
     *
     * @var array
     */
    protected $_config = array(
        'default' => array(
            'host'      => '127.0.0.1',
            'port'      => 11211,
            'weight'    => 1
        )
    );

    // ------------------------------------------------------------------------

    /**
     * Class constructor
     *
     * Setup Memcache(d)
     *
     * @return  void
     */
    public function __construct()
    {
        // Try to load memcached server info from the config file.
        $CI = & get_instance();
        $defaults = $this->_config['default'];

        if ($CI->config->load('memcached', true, true)) {
            $this->_config = $CI->config->config['memcached'];
        }

        if (class_exists('Memcached', false)) {
            $this->_memcached = new Memcached();
        } elseif (class_exists('Memcache', false)) {
            $this->_memcached = new Memcache();
        } else {
            log_message('error', 'Cache: Failed to create Memcache(d) object; extension not loaded?');
            return;
        }

        foreach ($this->_config as $cache_server) {
            isset($cache_server['hostname']) or $cache_server['hostname'] = $defaults['host'];
            isset($cache_server['port']) or $cache_server['port'] = $defaults['port'];
            isset($cache_server['weight']) or $cache_server['weight'] = $defaults['weight'];

            if ($this->_memcached instanceof Memcache) {
                // Third parameter is persistence and defaults to TRUE.
                $this->_memcached->addServer(
                    $cache_server['hostname'],
                    $cache_server['port'],
                    true,
                    $cache_server['weight']
                );
            } elseif ($this->_memcached instanceof Memcached) {
                $this->_memcached->addServer(
                    $cache_server['hostname'],
                    $cache_server['port'],
                    $cache_server['weight']
                );
            }
        }
    }

    // ------------------------------------------------------------------------

    /**
     * Fetch from cache
     *
     * @param   string  $id Cache ID
     * @return  mixed   Data on success, FALSE on failure
     */
    public function get($id)
    {
        $data = $this->_memcached->get($id);

        return is_array($data) ? $data[0] : $data;
    }

    // ------------------------------------------------------------------------

    /**
     * Save
     *
     * @param   string  $id Cache ID
     * @param   mixed   $data   Data being cached
     * @param   int $ttl    Time to live
     * @param   bool    $raw    Whether to store the raw value
     * @return  bool    TRUE on success, FALSE on failure
     */
    public function save($id, $data, $ttl = 60, $raw = false)
    {
        if ($raw !== true) {
            $data = array($data, time(), $ttl);
        }

        if ($this->_memcached instanceof Memcached) {
            return $this->_memcached->set($id, $data, $ttl);
        } elseif ($this->_memcached instanceof Memcache) {
            return $this->_memcached->set($id, $data, 0, $ttl);
        }

        return false;
    }

    // ------------------------------------------------------------------------

    /**
     * Delete from Cache
     *
     * @param   mixed   $id key to be deleted.
     * @return  bool    true on success, false on failure
     */
    public function delete($id)
    {
        return $this->_memcached->delete($id);
    }

    // ------------------------------------------------------------------------

    /**
     * Increment a raw value
     *
     * @param   string  $id Cache ID
     * @param   int $offset Step/value to add
     * @return  mixed   New value on success or FALSE on failure
     */
    public function increment($id, $offset = 1)
    {
        if (($result = $this->_memcached->increment($id, $offset)) === false) {
            return $this->_memcached->add($id, $offset) ? $offset : false;
        }

        return $result;
    }

    // ------------------------------------------------------------------------

    /**
     * Decrement a raw value
     *
     * @param   string  $id Cache ID
     * @param   int $offset Step/value to reduce by
     * @return  mixed   New value on success or FALSE on failure
     */
    public function decrement($id, $offset = 1)
    {
        if (($result = $this->_memcached->decrement($id, $offset)) === false) {
            return $this->_memcached->add($id, 0) ? 0 : false;
        }

        return $result;
    }

    // ------------------------------------------------------------------------

    /**
     * Clean the Cache
     *
     * @return  bool    false on failure/true on success
     */
    public function clean()
    {
        return $this->_memcached->flush();
    }

    // ------------------------------------------------------------------------

    /**
     * Cache Info
     *
     * @return  mixed   array on success, false on failure
     */
    public function cache_info()
    {
        return $this->_memcached->getStats();
    }

    // ------------------------------------------------------------------------

    /**
     * Get Cache Metadata
     *
     * @param   mixed   $id key to get cache metadata on
     * @return  mixed   FALSE on failure, array on success.
     */
    public function get_metadata($id)
    {
        $stored = $this->_memcached->get($id);

        if (count($stored) !== 3) {
            return false;
        }

        list($data, $time, $ttl) = $stored;

        return array(
            'expire'    => $time + $ttl,
            'mtime'     => $time,
            'data'      => $data
        );
    }

    // ------------------------------------------------------------------------

    /**
     * Is supported
     *
     * Returns FALSE if memcached is not supported on the system.
     * If it is, we setup the memcached object & return TRUE
     *
     * @return  bool
     */
    public function is_supported()
    {
        return (extension_loaded('memcached') or extension_loaded('memcache'));
    }

    // ------------------------------------------------------------------------

    /**
     * Class destructor
     *
     * Closes the connection to Memcache(d) if present.
     *
     * @return  void
     */
    public function __destruct()
    {
        if ($this->_memcached instanceof Memcache) {
            $this->_memcached->close();
        } elseif ($this->_memcached instanceof Memcached && method_exists($this->_memcached, 'quit')) {
            $this->_memcached->quit();
        }
    }
}