<?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 Session Driver Class
 *
 * @package	CodeIgniter
 * @subpackage	Libraries
 * @category	Sessions
 * @author	Andrey Andreev
 * @link	https://codeigniter.com/user_guide/libraries/sessions.html
 */
abstract class CI_Session_driver implements SessionHandlerInterface {

    protected $_config;

    /**
     * Data fingerprint
     *
     * @var	bool
     */
    protected $_fingerprint;

    /**
     * Lock placeholder
     *
     * @var	mixed
     */
    protected $_lock = FALSE;

    /**
     * Read session ID
     *
     * Used to detect session_regenerate_id() calls because PHP only calls
     * write() after regenerating the ID.
     *
     * @var	string
     */
    protected $_session_id;

    /**
     * Success and failure return values
     *
     * Necessary due to a bug in all PHP 5 versions where return values
     * from userspace handlers are not handled properly. PHP 7 fixes the
     * bug, so we need to return different values depending on the version.
     *
     * @see	https://wiki.php.net/rfc/session.user.return-value
     * @var	mixed
     */
    protected $_success, $_failure;

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

    /**
     * Class constructor
     *
     * @param	array	$params	Configuration parameters
     * @return	void
     */
    public function __construct(&$params) {
        $this->_config = & $params;

        if (is_php('7')) {
            $this->_success = TRUE;
            $this->_failure = FALSE;
        } else {
            $this->_success = 0;
            $this->_failure = -1;
        }
    }

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

    /**
     * Cookie destroy
     *
     * Internal method to force removal of a cookie by the client
     * when session_destroy() is called.
     *
     * @return	bool
     */
    protected function _cookie_destroy() {
        return setcookie(
                $this->_config['cookie_name'], NULL, 1, $this->_config['cookie_path'], $this->_config['cookie_domain'], $this->_config['cookie_secure'], TRUE
        );
    }

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

    /**
     * Get lock
     *
     * A dummy method allowing drivers with no locking functionality
     * (databases other than PostgreSQL and MySQL) to act as if they
     * do acquire a lock.
     *
     * @param	string	$session_id
     * @return	bool
     */
    protected function _get_lock($session_id) {
        $this->_lock = TRUE;
        return TRUE;
    }

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

    /**
     * Release lock
     *
     * @return	bool
     */
    protected function _release_lock() {
        if ($this->_lock) {
            $this->_lock = FALSE;
        }

        return TRUE;
    }

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

    /**
     * Fail
     *
     * Drivers other than the 'files' one don't (need to) use the
     * session.save_path INI setting, but that leads to confusing
     * error messages emitted by PHP when open() or write() fail,
     * as the message contains session.save_path ...
     * To work around the problem, the drivers will call this method
     * so that the INI is set just in time for the error message to
     * be properly generated.
     *
     * @return	mixed
     */
    protected function _fail() {
        ini_set('session.save_path', config_item('sess_save_path'));
        return $this->_failure;
    }

}
