<?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 3.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * CodeIgniter Wincache Caching Class
 *
 * Read more about Wincache functions here:
 * http://www.php.net/manual/en/ref.wincache.php
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Core
 * @author		Mike Murkovic
 * @link
 */
class CI_Cache_wincache 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 Wincache; extension not loaded/enabled?');
        }
    }

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

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

        // Success returned by reference from wincache_ucache_get()
        return ($success) ? $data : FALSE;
    }

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

    /**
     * Cache Save
     *
     * @param	string	$id	Cache ID
     * @param	mixed	$data	Data to store
     * @param	int	$ttl	Time to live (in seconds)
     * @param	bool	$raw	Whether to store the raw value (unused)
     * @return	bool	true on success/false on failure
     */
    public function save($id, $data, $ttl = 60, $raw = FALSE) {
        return wincache_ucache_set($id, $data, $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($id) {
        return wincache_ucache_delete($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) {
        $success = FALSE;
        $value = wincache_ucache_inc($id, $offset, $success);

        return ($success === TRUE) ? $value : FALSE;
    }

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

    /**
     * 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) {
        $success = FALSE;
        $value = wincache_ucache_dec($id, $offset, $success);

        return ($success === TRUE) ? $value : FALSE;
    }

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

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

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

    /**
     * Cache Info
     *
     * @return	mixed	array on success, false on failure
     */
    public function cache_info() {
        return wincache_ucache_info(TRUE);
    }

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

    /**
     * Get Cache Metadata
     *
     * @param	mixed	key to get cache metadata on
     * @return	mixed	array on success/false on failure
     */
    public function get_metadata($id) {
        if ($stored = wincache_ucache_info(FALSE, $id)) {
            $age = $stored['ucache_entries'][1]['age_seconds'];
            $ttl = $stored['ucache_entries'][1]['ttl_seconds'];
            $hitcount = $stored['ucache_entries'][1]['hitcount'];

            return array(
                'expire' => $ttl - $age,
                'hitcount' => $hitcount,
                'age' => $age,
                'ttl' => $ttl
            );
        }

        return FALSE;
    }

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

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

}
