<?
/*
* This file is part of Webgenerator-X,
* an object oriented website management engine working an top of
* Apache/PHP4/MySQL.
* http://www.webgenerator-x.com
* @2001 REGNI Giorgio
* hide@address.com
*
* Webgenerator-X is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Webgenerator-X is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Foobar; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

/*************************************************************************/
/* REGNI Giorgio
   20/04/2001
   WG-X
   Cache File, WG-X Cache Engine
   This file allow module to know if they need to upadte specific content
   or can retreive them from file.
   
   A data is named by its module and its data_code.
   
   The Cache Data itself is a small php script which set 2 variables with content and time

   20/05/2001 added clear_cache
*/

class A_CacheEngine
{

	var $cache_dir;
	var $WIN32;
	var $nosql=false;
	
	var $CACHED_FILE = array();			// stores file there to cache multiples fopen
										// only data is stored here, not the timestamp

	var $time;							// actual time ( the same time is used through the script)
	
	// Must know where to store the data
	// No trailing slash
	// Use default cache dir if nothing entered
	function A_CacheEngine($newcache_dir="")
	{
		global $win32,$cache_dir,$databaseoff,$cache_expire,$root_dir;
		
		$this->WIN32 = $win32;
		
		if ($newcache_dir!="")
			$this->cache_dir =$newcache_dir;
		else
			$this->cache_dir = $cache_dir;
		
		$this->cache_dir = $root_dir.'/'.$this->cache_dir;
		$this->nosql = $databaseoff;
		$this->time = date ("U");
	}

	
	// Get the cache Data associated with the data_code
	// return an array [ok] bool succes
	// [data] the data in the cache if success
	// need to call is uptodate first,else the file is not loaded !
	function Get_Data($module,$data_code,$tags="")
	{
		$filename = $this->Generate_Filename( $module,$data_code,$tags );
		
		// check the file is opened
		if ( isset($this->CACHED_FILE[ $filename ]) )
		{
			// file in cache
			return array(ok=>true,data=>$this->CACHED_FILE[  $filename ]);
		}
		else
			return array(ok=>false,data=>"You need to call Is_Uptodate first !");
	}
	
	// Store the cache Data associated with the data_code and tags
	// return bool success
	// you can specify how many time to try before aborting
	function Store_Data($module,$data_code,$tags,$data)
	{
		global $db_prefix;
		
		$success=false;
		$max_try = 5;
		
		$filename = $this->Generate_Filename( $module,$data_code,$tags );
		
		$data = "<? \$modtime=$this->time;\n \$data='".addslashes($data)."'; ?>";
		
		for( $i=0; ($i<$max_try) and ($success==false);$i++)
		{
			if ( $fp=fopen( $filename, "w" ) )
			{
				// file opened
				if ( flock($fp,3) == true )	// lock writing
				{
					if	(fwrite($fp,$data) == true)
					{
						$success = true;
					}
				}
				
				fclose( $fp );
			}
			else
					usleep(10);	// WAIT 10msecond
		}
		
		return $success;
	}
	
	// return true if cache file exist else return false
	// if file exist, cache it in CACHE_FILE[] too
	// $expire = time laps to say cache is too old (seconds)
	// $expire = 0 : this module data is always taken from cache
	function Is_UptoDate($module,$data_code,$tags,$expire)
	{
		$noneedupdate = false;
		$filename = $this->Generate_Filename( $module,$data_code,$tags );

		if (file_exists($filename))
		{
			// If the cache file exist, go.
			// I am so proud of this !!!!!
			// using include... i am great !
			// this include set values $modtime and $data
			include ($filename);
			
			if ($expire==0 or $this->nosql)				// =0 means always cache + take from cache if mysql not available now
			{
				$this->CACHED_FILE[$filename] = stripslashes($data);
				$noneedupdate = true;
			}
			else
			{
				if (($modtime + $expire) > $this->time)
				{
					$this->CACHED_FILE[$filename] = stripslashes($data);
					$noneedupdate = true;
				}
			}
		}
		
		return $noneedupdate;
	}
	
	// delete a cache file
	// used to force update after changes
	// delete all languages and tags belonging to $module $data_code
	// return true also if the cache entry did not exist
	function clear_cache($module,$data_code)
	{
		global $root_dir,$cache_dir;
		
		$ok =true;
		
		$cache = $root_dir."/".$cache_dir."/";
		
		$match = "^[a-zA-Z0-9]*" . "-".strtolower(trim($module))."-".strtolower(trim($data_code))."-". "[a-zA-Z0-9\-]*$";
		$handle=opendir($cache);
		while (($file = readdir($handle))!=false) {
			if (ereg($match, $file))
			{
				//echo "$cache.$file<br>\n";
				if (!unlink ( $cache.$file ))
					$ok = false;
			}
		}
		closedir($handle); 

		return $ok;
	}
		
	// generate a filename with $module-$data_code-implode($tags)
	// use a implode of the array $tags or $tags if not array
	function Generate_Filename( $module,$data_code,$tags="" )
	{
		global $language;		// cache are different uppon language
		
		if ($tags!="" and is_array($tags) )
			$tags=implode('-',$tags);
		
		$module = strtolower(trim($module)); 
		$data_code = strtolower(trim($data_code)); 
		$tags = strtolower(trim($tags)); 

		return concat_dirs($this->cache_dir,$language."-".$module."-".$data_code."-".$tags);
	}
} // End Class
?>