public static function init($config = NULL) { self::$extensions = array(); if (is_null($config)) { $config = MANIFEST . '/extensions.xml'; } if (!file_exists($config)) { self::$extension_configuration = new SimpleXMLElement('<extensions></extensions>'); } else { $previous = libxml_use_internal_errors(true); self::$extension_configuration = simplexml_load_file($config); libxml_use_internal_errors($previous); if (!self::$extension_configuration instanceof SimpleXMLElement) { throw new ExtensionException('Failed to load Extension configuration file ' . $config); } } }