public static function get_cache_busted_file_url($file)
 {
     if ($ext = pathinfo($file, PATHINFO_EXTENSION)) {
         if ($ext == 'js' || $ext == 'css') {
             $myExt = strstr($file, 'combined.' . $ext) ? 'combined.' . $ext : $ext;
             $filePath = preg_replace('/\\?.*/', '', Director::baseFolder() . '/' . $file);
             $mTime = Requirements::get_suffix_requirements() ? "." . filemtime($filePath) : '';
             $suffix = '';
             if (strpos($file, '?') !== false) {
                 $suffix = substr($file, strpos($file, '?'));
             }
             return str_replace('.' . $myExt, '', $file) . "{$mTime}.{$myExt}{$suffix}";
         }
     }
     return false;
 }