public function add_file( $file, array $atts = array() ) {

		$parent = $this->get_file( dirname( $file ) );
		$filename = basename( $file );

		if ( false === $parent || true === isset( $parent->contents->$filename ) ) {
			return false;
		}

		$parent->contents->$filename = $this->get_default_atts( $atts );

		return true;
	}