<?php

/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2017, British Columbia Institute of Technology
 *
 * 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 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
 * @license	http://opensource.org/licenses/MIT	MIT License
 * @link	https://codeigniter.com
 * @since	Version 2.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * CodeIgniter APC Caching Class
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Core
 * @author		EllisLab Dev Team
 * @link
 */
class CI_Cache_apc extends CI_Driver {

    /**
     * Class constructor
     *
     * Only present so that an error message is logged
     * if APC is not available.
     *
     * @return	void
     */
    public function __construct() {
        if (!$this->is_supported()) {
            log_message('error', 'Cache: Failed to initialize APC; extension not loaded/enabled?');
        }
    }

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

    /**
     * Get
     *
     * Look for a value in the cache. If it exists, return the data
     * if not, return FALSE
     *
     * @param	string
     * @return	mixed	value that is stored/FALSE on failure
     */
    public function get($id) {
        $success = FALSE;
        $data = apc_fetch($id, $success);

        if ($success === TRUE) {
            return is_array($data) ? unserialize($data[0]) : $data;
        }

        return FALSE;
    }

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

    /**
     * Cache Save
     *
     * @param	string	$id	Cache ID
     * @param	mixed	$data	Data to store
     * @param	int	$ttl	Length of time (in seconds) to cache the data
     * @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) {
        $ttl = (int) $ttl;

        return apc_store(
                $id, ($raw === TRUE ? $data : array(serialize($data), time(), $ttl)), $ttl
        );
    }

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

    /**
     * Delete from Cache
     *
     * @param	mixed	unique identifier of the item in the cache
     * @return	bool	true on success/false on failure
     */
    public function delete($id) {
        return apc_delete($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, $offset = 1) {
        return apc_inc($id, $offset);
    }

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

    /**
     * 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, $offset = 1) {
        return apc_dec($id, $offset);
    }

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

    /**
     * Clean the cache
     *
     * @return	bool	false on failure/true on success
     */
    public function clean() {
        return apc_clear_cache('user');
    }

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

    /**
     * Cache Info
     *
     * @param	string	user/filehits
     * @return	mixed	array on success, false on failure
     */
    public function cache_info($type = NULL) {
        return apc_cache_info($type);
    }

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

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

        if ($success === FALSE OR count($stored) !== 3) {
            return FALSE;
        }

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

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

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

    /**
     * is_supported()
     *
     * Check to see if APC is available on this system, bail if it isn't.
     *
     * @return	bool
     */
    public function is_supported() {
        return (extension_loaded('apc') && ini_get('apc.enabled'));
    }

}
