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<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
* CodeIgniter
*
* An open source application development framework for PHP 4.3.2 or newer
*
* @package CodeIgniter
* @author ExpressionEngine Dev Team
* @copyright Copyright (c) 2008 - 2010, EllisLab, Inc.
* @license http://codeigniter.com/user_guide/license.html
* @link http://codeigniter.com
* @since Version 1.0
* @filesource
*/
// ------------------------------------------------------------------------
/**
* Database Cache Class
*
* @category Database
* @author ExpressionEngine Dev Team
* @link http://codeigniter.com/user_guide/database/
*/
class CI_DB_Cache {
var $CI;
var $db; // allows passing of db object so that multiple database connections and returned db objects can be supported
/**
* Constructor
*
* Grabs the CI super object instance so we can access it.
*
*/
function CI_DB_Cache(&$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;
$this->CI->load->helper('file');
}
// --------------------------------------------------------------------
/**
* Set Cache Directory Path
*
* @access public
* @param string the path to the cache directory
* @return bool
*/
function check_path($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
$path = preg_replace("/(.+?)\/*$/", "\\1/", $path);
if ( ! is_dir($path) OR ! is_really_writable($path))
{
// If the path is wrong we'll turn off caching
return $this->db->cache_off();
}
$this->db->cachedir = $path;
return TRUE;
}
// --------------------------------------------------------------------
/**
* Retrieve a cached query
*
* The URI being requested will become the name of the cache sub-folder.
* An MD5 hash of the SQL statement will become the cache file name
*
* @access public
* @return string
*/
function read($sql)
{
if ( ! $this->check_path())
{
return $this->db->cache_off();
}
$segment_one = ($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 (FALSE === ($cachedata = read_file($filepath)))
{
return FALSE;
}
return unserialize($cachedata);
}
// --------------------------------------------------------------------
/**
* Write a query to a cache file
*
* @access public
* @return bool
*/
function write($sql, $object)
{
if ( ! $this->check_path())
{
return $this->db->cache_off();
}
$segment_one = ($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($dir_path))
{
if ( ! @mkdir($dir_path, DIR_WRITE_MODE))
{
return FALSE;
}
@chmod($dir_path, DIR_WRITE_MODE);
}
if (write_file($dir_path.$filename, serialize($object)) === FALSE)
{
return FALSE;
}
@chmod($dir_path.$filename, FILE_WRITE_MODE);
return TRUE;
}
// --------------------------------------------------------------------
/**
* Delete cache files within a particular directory
*
* @access public
* @return bool
*/
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
*
* @access public
* @return bool
*/
function delete_all()
{
delete_files($this->db->cachedir, TRUE);
}
}
/* End of file DB_cache.php */
/* Location: ./system/database/DB_cache.php */
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