private static function _get_file_path( $base, $subdir, $filename ) {
		if ( URLHelper::is_url($subdir) ) {
			$subdir = URLHelper::url_to_file_system($subdir);
		}
		$subdir = self::maybe_realpath($subdir);

		$path = '';
		if ( self::BASE_UPLOADS == $base ) {
			//it is in the Uploads directory
			$upload_dir = wp_upload_dir();
			$path = $upload_dir['basedir'];
		} else if ( self::BASE_CONTENT == $base ) {
			//it is in the content directory, somewhere else ...
			$path = WP_CONTENT_DIR;
		}
		if ( self::is_in_theme_dir(trailingslashit($subdir).$filename) ) {
			//this is for weird installs when the theme folder is outside of /wp-content
			return trailingslashit($subdir).$filename;
		}
		if ( !empty($subdir) ) {
			$path = trailingslashit($path).$subdir;
		}
		$path = trailingslashit($path).$filename;

		return URLHelper::remove_double_slashes($path);
	}