allow a more flexible way of using user backends

lib/base.php

@@ -345,7 +345,7 @@ class OC{
 			$_SESSION['user_id'] = '';
 		}
 
-		OC_User::useBackend( OC_Config::getValue( "userbackend", "database" ));
+		OC_User::useBackend(new OC_User_Database());
 		OC_Group::useBackend(new OC_Group_Database());
 
 		// Load Apps

lib/user.php

@@ -50,8 +50,8 @@ class OC_User {
 	 *
 	 * Makes a list of backends that can be used by other modules
 	 */
-	public static function registerBackend( $name ){
-		self::$_backends[] = $name;
+	public static function registerBackend( $backend ){
+		self::$_backends[] = $backend;
 		return true;
 	}
 
@@ -83,6 +83,9 @@ class OC_User {
 	 * Set the User Authentication Module
 	 */
 	public static function useBackend( $backend = 'database' ){
+		if($backend instanceof OC_User_Backend){
+			self::$_usedBackends[get_class($backend)]=$backend;
+		}else{
 			// You'll never know what happens
 			if( null === $backend OR !is_string( $backend )){
 				$backend = 'database';
@@ -100,6 +103,7 @@ class OC_User {
 					self::$_usedBackends[$backend] = new $className();
 					break;
 			}
+		}
 
 		true;
 	}