db.php

<?php
/**
 * ownCloud
 *
 * @author Frank Karlitschek
 * @copyright 2012 Frank Karlitschek frank@owncloud.org
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or any later version.
 *
 * This library 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 AFFERO GENERAL PUBLIC LICENSE for more details.
 *
 * You should have received a copy of the GNU Affero General Public
 * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

/**
 * This class manages the access to the database. It basically is a wrapper for
 * MDB2 with some adaptions.
 */
class OC_DB {
	const BACKEND_PDO=0;
	const BACKEND_MDB2=1;
	
	static private $connection; //the prefered connection to use, either PDO or MDB2
	static private $backend=null;
	static private $MDB2=false;
	static private $PDO=false;
	static private $schema=false;
	static private $affected=0;
	static private $result=false;
	static private $inTransaction=false;
	static private $prefix=null;
	static private $type=null;

	/**
	 * check which backend we should use
	 * @return BACKEND_MDB2 or BACKEND_PDO
	 */
	private static function getDBBackend(){
		$backend=self::BACKEND_MDB2;
		if(class_exists('PDO') && OC_Config::getValue('installed', false)){//check if we can use PDO, else use MDB2 (instalation always needs to be done my mdb2)
			$type = OC_Config::getValue( "dbtype", "sqlite" );
			if($type=='sqlite3') $type='sqlite';
			$drivers=PDO::getAvailableDrivers();
			if(array_search($type,$drivers)!==false){
				$backend=self::BACKEND_PDO;
			}
		}
	}
	
	/**
	 * @brief connects to the database
	 * @returns true if connection can be established or nothing (die())
	 *
	 * Connects to the database as specified in config.php
	 */
	public static function connect($backend=null){
		if(self::$connection){
			return;
		}
		if(is_null($backend)){
			$backend=self::getDBBackend();
		}