internal static string GetDirectoryRootCore(KernelTransaction transaction, string path, PathFormat pathFormat)
{
Path.CheckInvalidUncPath(path);
string pathLp = Path.GetExtendedLengthPathCore(transaction, path, pathFormat, GetFullPathOptions.CheckInvalidPathChars);
pathLp = Path.GetRegularPathCore(pathLp, GetFullPathOptions.None, false);
string rootPath = Path.GetPathRoot(pathLp, false);
return(Utils.IsNullOrWhiteSpace(rootPath) ? null : rootPath);
}