/// <summary>
/// Indicates whether the given path is a UNC or drive pattern root directory.
/// <para>Note: This function mimics the behavior of checking if Path.GetDirectoryName(path) == null.</para>
/// </summary>
/// <param name="path"></param>
/// <returns></returns>
private static bool IsRootDirectory(string path)
{
// Eliminate all non-rooted paths
if (!Path.IsPathRooted(path))
{
return(false);
}
int uncMatchLength = FileUtilitiesRegex.StartsWithUncPatternMatchLength(path);
// Determine if the given path is a standard drive/unc pattern root
if (FileUtilitiesRegex.IsDrivePattern(path) ||
FileUtilitiesRegex.IsDrivePatternWithSlash(path) ||
uncMatchLength == path.Length)
{
return(true);
}
// Eliminate all non-root unc paths.
if (uncMatchLength != -1)
{
return(false);
}
// Eliminate any drive patterns that don't have a slash after the colon or where the 4th character is a non-slash
// A non-slash at [3] is specifically checked here because Path.GetDirectoryName
// considers "C:///" a valid root.
if (FileUtilitiesRegex.StartsWithDrivePattern(path) &&
((path.Length >= 3 && path[2] != '\\' && path[2] != '/') ||
(path.Length >= 4 && path[3] != '\\' && path[3] != '/')))
{
return(false);
}
// There are some edge cases that can get to this point.
// After eliminating valid / invalid roots, fall back on original behavior.
return(Path.GetDirectoryName(path) == null);
}
