From 9e9d77b4072de4f8c73e8bbade07a8f27734e4bd Mon Sep 17 00:00:00 2001
From: Florian Pritz <bluewind@xssn.at>
Date: Sat, 6 Feb 2010 23:14:56 +0100
Subject: Initial commit

Signed-off-by: Florian Pritz <bluewind@xssn.at>
---
 system/database/DB_cache.php | 195 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 195 insertions(+)
 create mode 100644 system/database/DB_cache.php

(limited to 'system/database/DB_cache.php')

diff --git a/system/database/DB_cache.php b/system/database/DB_cache.php
new file mode 100644
index 000000000..8b0ad4fb4
--- /dev/null
+++ b/system/database/DB_cache.php
@@ -0,0 +1,195 @@
+<?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 - 2009, 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, DIR_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 */
\ No newline at end of file
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