public function readDirRecursive( $dir, $pattern ) {

		$sub_dirs = glob( $dir . '/*', \GLOB_ONLYDIR );
		$files = array();
		if ( ! empty( $sub_dirs ) ) {
			foreach ( $sub_dirs as $sub_dir ) {
				$files = array_merge( $files, $this->readDirRecursive( $sub_dir, $pattern ) );
			}
		}
		$files = array_merge( $files, glob( $dir . '/' . $pattern, \GLOB_NOCHECK ) );

		return $files;
	}