Subversion-Projekte lars-tiefland.ci

<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2019, 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 - 2019, British Columbia Institute of Technology (https://bcit.ca/)
 * @license     https://opensource.org/licenses/MIT     MIT License
 * @link        https://codeigniter.com
 * @since       Version 1.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * Database Cache Class
 *
 * @category    Database
 * @author              EllisLab Dev Team
 * @link                https://codeigniter.com/user_guide/database/
 */
class CI_DB_Cache {

        /**
         * CI Singleton
         *
         * @var object
         */
        public $CI;

        /**
         * Database object
         *
         * Allows passing of DB object so that multiple database connections
         * and returned DB objects can be supported.
         *
         * @var object
         */
        public $db;

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

        /**
         * Constructor
         *
         * @param       object  &$db
         * @return      void
         */
        public function __construct(&$db)
        {
                // Assign the main CI object to $this->CI and load the file helper since we use it a lot
                $this->CI =& get_instance();
                $this->db =& $db;
                $this->CI->load->helper('file');

                $this->check_path();
        }

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

        /**
         * Set Cache Directory Path
         *
         * @param       string  $path   Path to the cache directory
         * @return      bool
         */
        public function check_path($path = '')
        {
                if ($path === '')
                {
                        if ($this->db->cachedir === '')
                        {
                                return $this->db->cache_off();
                        }

                        $path = $this->db->cachedir;
                }

                // Add a trailing slash to the path if needed
                $path = realpath($path)
                        ? rtrim(realpath($path), DIRECTORY_SEPARATOR).DIRECTORY_SEPARATOR
                        : rtrim($path, '/').'/';

                if ( ! is_dir($path))
                {
                        log_message('debug', 'DB cache path error: '.$path);

                        // If the path is wrong we'll turn off caching
                        return $this->db->cache_off();
                }

                if ( ! is_really_writable($path))
                {
                        log_message('debug', 'DB cache dir not writable: '.$path);

                        // If the path is not really writable we'll turn off caching
                        return $this->db->cache_off();
                }

                $this->db->cachedir = $path;
                return TRUE;
        }

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

        /**
         * Retrieve a cached query
         *
         * The URI being requested will become the name of the cache sub-folder.
         * An MD5 hash of the SQL statement will become the cache file name.
         *
         * @param       string  $sql
         * @return      string
         */
        public function read($sql)
        {
                $segment_one = ($this->CI->uri->segment(1) == FALSE) ? 'default' : $this->CI->uri->segment(1);
                $segment_two = ($this->CI->uri->segment(2) == FALSE) ? 'index' : $this->CI->uri->segment(2);
                $filepath = $this->db->cachedir.$segment_one.'+'.$segment_two.'/'.md5($sql);

                if ( ! is_file($filepath) OR FALSE === ($cachedata = file_get_contents($filepath)))
                {
                        return FALSE;
                }

                return unserialize($cachedata);
        }

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

        /**
         * Write a query to a cache file
         *
         * @param       string  $sql
         * @param       object  $object
         * @return      bool
         */
        public function write($sql, $object)
        {
                $segment_one = ($this->CI->uri->segment(1) == FALSE) ? 'default' : $this->CI->uri->segment(1);
                $segment_two = ($this->CI->uri->segment(2) == FALSE) ? 'index' : $this->CI->uri->segment(2);
                $dir_path = $this->db->cachedir.$segment_one.'+'.$segment_two.'/';
                $filename = md5($sql);

                if ( ! is_dir($dir_path) && ! @mkdir($dir_path, 0750))
                {
                        return FALSE;
                }

                if (write_file($dir_path.$filename, serialize($object)) === FALSE)
                {
                        return FALSE;
                }

                chmod($dir_path.$filename, 0640);
                return TRUE;
        }

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

        /**
         * Delete cache files within a particular directory
         *
         * @param       string  $segment_one
         * @param       string  $segment_two
         * @return      void
         */
        public function delete($segment_one = '', $segment_two = '')
        {
                if ($segment_one === '')
                {
                        $segment_one  = ($this->CI->uri->segment(1) == FALSE) ? 'default' : $this->CI->uri->segment(1);
                }

                if ($segment_two === '')
                {
                        $segment_two = ($this->CI->uri->segment(2) == FALSE) ? 'index' : $this->CI->uri->segment(2);
                }

                $dir_path = $this->db->cachedir.$segment_one.'+'.$segment_two.'/';
                delete_files($dir_path, TRUE);
        }

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

        /**
         * Delete all existing cache files
         *
         * @return      void
         */
        public function delete_all()
        {
                delete_files($this->db->cachedir, TRUE, TRUE);
        }

}