private static int GetDirectoryOrRootLength(string path, bool skipTrailingSlash = false)
{
int rootLength;
PathFormat pathFormat = Paths.GetPathFormat(path, out rootLength);
if (pathFormat == PathFormat.UnknownFormat)
{
return(-1);
}
int length = path.Length;
if (rootLength == path.Length)
{
return(length);
}
if (skipTrailingSlash && EndsInDirectorySeparator(path))
{
length--;
}
while (((length > rootLength) &&
(path[--length] != DirectorySeparator)) &&
(path[length] != AltDirectorySeparator))
{
}
return(length);
}
/// <summary>
/// Get the canonical volume root (e.g. the \\?\VolumeGuid format) for the given path. The path must not be relative.
/// </summary>
/// <exception cref="ArgumentException">Thrown if the path is relative or indeterminate.</exception>
/// <exception cref="System.IO.IOException">Thrown if unable to get the root from the OS.</exception>
public static string GetCanonicalRoot(this IExtendedFileService extendedFileService, IFileService fileService, string path)
{
if (Paths.IsPartiallyQualified(path))
{
throw new ArgumentException(nameof(path));
}
path = fileService.GetFullPath(path);
int rootLength;
var format = Paths.GetPathFormat(path, out rootLength);
if (format == PathFormat.UnknownFormat)
{
throw new ArgumentException(nameof(format));
}
string root = path.Substring(0, rootLength);
string canonicalRoot = root;
switch (format)
{
case PathFormat.UniformNamingConvention:
if (Paths.IsDevice(path))
{
canonicalRoot = @"\\" + root.Substring(Paths.ExtendedUncPrefix.Length);
}
break;
case PathFormat.LocalFullyQualified:
canonicalRoot = extendedFileService.GetVolumeName(root);
break;
}
return(canonicalRoot);
}
/// <summary>
/// Gets the format and root length of the specified path. Returns -1 for the root length
/// if the path format can't be determined.
/// </summary>
/// <remarks>
/// Does not look for invalid characters beyond what makes for an indeterminate path.
/// </remarks>
public unsafe static PathFormat GetPathFormat(string path, out int rootLength)
{
if (path == null || path.Length == 0 || path[0] == ':')
{
rootLength = -1;
return(PathFormat.UnknownFormat);
}
fixed(char *start = path)
{
return(Paths.GetPathFormat(start, path.Length, out rootLength));
}
}
/// <summary>
/// Get the canonical volume root (e.g. the \\?\VolumeGuid format) for the given path. The path must not be relative.
/// </summary>
/// <exception cref="ArgumentException">Thrown if the path is relative or indeterminate.</exception>
/// <exception cref="System.IO.IOException">Thrown if unable to get the root from the OS.</exception>
public static string GetCanonicalRoot(this IExtendedFileService extendedFileService, IFileService fileService, string path)
{
if (Paths.IsRelative(path))
{
throw new ArgumentException();
}
path = fileService.GetFullPath(path);
int rootLength;
var format = Paths.GetPathFormat(path, out rootLength);
if (format == PathFormat.UnknownFormat)
{
throw new ArgumentException();
}
string root = path.Substring(0, rootLength);
string simpleRoot = root;
string canonicalRoot = root;
switch (format)
{
case PathFormat.UniformNamingConventionExtended:
simpleRoot = @"\\" + root.Substring(Paths.ExtendedUncPrefix.Length);
goto case PathFormat.UniformNamingConvention;
case PathFormat.UniformNamingConvention:
canonicalRoot = simpleRoot;
break;
case PathFormat.VolumeAbsoluteExtended:
case PathFormat.DriveAbsolute:
canonicalRoot = extendedFileService.GetVolumeName(root);
simpleRoot = extendedFileService.GetMountPoint(root);
break;
}
return(canonicalRoot);
}