| private static UpdateDeviceMappings ( ) : void | ||
| return | void | |
/// <summary>
/// Changes the DOS device name for the <paramref name="path"/> given to the according drive letter.
/// </summary>
/// <param name="path">Path to replace DOS device name for.</param>
/// <returns>New path string.</returns>
/// <exception cref="ArgumentNullException"><paramref name="path"/> is <see langword="null"/> or empty.</exception>
/// <exception cref="ArgumentException"><paramref name="path"/> does not start with a DOS device name.</exception>
/// <exception cref="InvalidOperationException">Drive letter could not be found for the <paramref name="path"/> given.</exception>
/// <remarks>
/// This method also supports UNC paths.
/// </remarks>
public static string ChangeDeviceNameToDriveLetter(string path)
{
if (string.IsNullOrEmpty(path))
{
throw new ArgumentNullException(nameof(path));
}
path = LongPathCommon.RemoveLongPathPrefix(path);
// Path is already converted.
if (Regex.IsMatch(path, @"^(?:\\\\|[a-z]:)", RegexOptions.IgnoreCase))
{
return(path);
}
if (!path.StartsWith(@"\Device\", StringComparison.OrdinalIgnoreCase))
{
throw new ArgumentException(string.Format(CultureInfo.InvariantCulture, "Path given does not start with a device name: {0}", path), nameof(path));
}
// Convert Network Redirector path to UNC.
if (path.StartsWith(@"\Device\Mup\", StringComparison.OrdinalIgnoreCase))
{
return(@"\\" + path.Substring(12));
}
string driveLetter;
string deviceName = null;
// Find the proper device name.
lock (PathHelper.DriveLetterToDeviceName)
{
Func <string> findDeviceName = () => deviceName = PathHelper.DriveLetterToDeviceName.Values.FirstOrDefault(dn => path.StartsWith(dn, StringComparison.OrdinalIgnoreCase));
if (findDeviceName() == null)
{
PathHelper.UpdateDeviceMappings();
if (findDeviceName() == null)
{
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, "Unable to find root path for {0}", path));
}
}
// Find the root path for the device name given.
driveLetter = PathHelper.DriveLetterToDeviceName.Keys.First(rp => string.Equals(PathHelper.DriveLetterToDeviceName[rp], deviceName));
}
// Change parent.
return(driveLetter + path.Substring(deviceName.Length));
}
/// <summary>
/// Changes the drive letter for the <paramref name="path"/> given to the according DOS device name.
/// </summary>
/// <param name="path">Path to replace the drive letter for.</param>
/// <returns>New path string.</returns>
/// <exception cref="ArgumentNullException"><paramref name="path"/> is <see langword="null"/> or empty.</exception>
/// <exception cref="ArgumentException"><paramref name="path"/> is too short.</exception>
/// <exception cref="InvalidOperationException">The according DOS device name could not be found.</exception>
/// <remarks>
/// This method also supports UNC paths.
/// </remarks>
public static string ChangeDriveLetterToDeviceName(string path)
{
if (string.IsNullOrEmpty(path))
{
throw new ArgumentNullException(nameof(path));
}
if (path.Length < 2)
{
throw new ArgumentException("Path is too short.", nameof(path));
}
// If the path is already converted, skip.
if (path.StartsWith(@"\Device\", StringComparison.OrdinalIgnoreCase))
{
return(path);
}
path = LongPathCommon.RemoveLongPathPrefix(path);
// Convert UNC path to a Network Redirector path.
if (path.StartsWith(@"\\", StringComparison.OrdinalIgnoreCase) || path.StartsWith(@"//", StringComparison.OrdinalIgnoreCase))
{
return(@"\Device\Mup\" + path.Substring(2));
}
// C:\, for example. Or will contain invalid string and will fail later.
string driveLetter = path.Substring(0, 2) + "\\";
string deviceName;
lock (PathHelper.DriveLetterToDeviceName)
{
// Update the device-root caches, if the root path is not there.
if (!PathHelper.DriveLetterToDeviceName.ContainsKey(driveLetter))
{
PathHelper.UpdateDeviceMappings();
if (!PathHelper.DriveLetterToDeviceName.ContainsKey(driveLetter))
{
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, "Unable to find DOS device name for path: {0}", path));
}
}
deviceName = PathHelper.DriveLetterToDeviceName[driveLetter];
}
// Change parent.
return(deviceName + path.Substring(driveLetter.Length));
}