PageCache.php

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<?php
/*-------------------------------------------------------------------------------
 * Xataface Web Application Framework
 * Copyright (C) 2005-2008 Web Lite Solutions Corp (shannah@sfu.ca)
 * 
 * This program 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.
 * 
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *-------------------------------------------------------------------------------
 */
require_once 'Cache/Lite.php';
require_once 'Dataface/Application.php';
class Dataface_PageCache extends Cache_Lite {

        var $tables;
        function Dataface_PageCache($tables=array()){
                $this->tables =& $tables;
                $app =& Dataface_Application::getInstance();
                $params = array(
                        'cacheDir' => $app->_conf['cache_dir'].'/dataface_page_cache',
                        'lifeTime' => 3600);
                
                
                if ( !file_exists($params['cacheDir']) ){
                        mkdir($params['cacheDir'], true);
                }
                if ( !file_exists($params['cacheDir']) ){
                        throw new Exception("Cannot create directory '".$params['cacheDir']."'", E_USER_ERROR);
                } else {
                        //echo $params['cacheDir'];
                }
                $this->Cache_Lite($params);
                
                
        }
        
        function dbmtime(){
                $tables =& $this->tables;
                $lookup = array_flip($tables);
                $app =& Dataface_Application::getInstance();
                $res = mysql_query("SHOW TABLE STATUS", $app->_db);
                $latestMod = 0;
                while ( $row = mysql_fetch_array($res) ){
                        if ( (sizeof($tables) === 0 || isset( $lookup[$row['Name']] ) ) && strtotime($row['Update_time']) > $latestMod ){
                                $latestMod = strtotime($row['Update_time']);
                        }
                }
                
                return $latestMod;
        
        }
        
        function get($id){
                $mtime = $this->dbmtime();
                $this->_setFileName($id,'default');
                if ( $mtime < $this->lastModified() ){
                        return parent::get($id);
                } else {
                        return false;
                }
        }
        
        
}