private static void GetFullPathName(string path, StringBuffer fullPath)
{
// If the string starts with an extended prefix we would need to remove it from the path before we call GetFullPathName as
// it doesn't root extended paths correctly. We don't currently resolve extended paths, so we'll just assert here.
Debug.Assert(PathInternal.IsRelative(path) || !PathInternal.IsExtended(path));
// Historically we would skip leading spaces *only* if the path started with a drive " C:" or a UNC " \\"
int startIndex = PathInternal.PathStartSkip(path);
fixed(char *pathStart = path)
{
uint result = 0;
while ((result = Interop.mincore.GetFullPathNameW(pathStart + startIndex, (uint)fullPath.CharCapacity, fullPath.GetHandle(), IntPtr.Zero)) > fullPath.CharCapacity)
{
// Reported size (which does not include the null) is greater than the buffer size. Increase the capacity.
fullPath.EnsureCharCapacity(result);
}
if (result == 0)
{
// Failure, get the error and throw
int errorCode = Marshal.GetLastWin32Error();
if (errorCode == 0)
{
errorCode = Interop.mincore.Errors.ERROR_BAD_PATHNAME;
}
throw Win32Marshal.GetExceptionForWin32Error(errorCode, path);
}
fullPath.Length = result;
}
}
private StringBuilder GetFullPathName(string path)
{
// Historically we would skip leading spaces *only* if the path started with a drive " C:" or a UNC " \\"
int startIndex = PathInternal.PathStartSkip(path);
int capacity = path.Length;
if (PathInternal.IsRelative(path))
{
// If the initial path is relative the final path will likely be no more than the current directory length (which can only
// be MaxPath) so we'll pick that as a reasonable start.
capacity += PathInternal.MaxShortPath;
}
else
{
// If the string starts with an extended prefix we would need to remove it from the path before we call GetFullPathName as
// it doesn't root extended paths correctly. We don't currently resolve extended paths, so we'll just assert here.
Debug.Assert(!PathInternal.IsExtended(path));
}
StringBuilder outputBuffer = this.GetOutputBuffer(capacity);
fixed(char *pathStart = path)
{
int result = 0;
while ((result = Interop.mincore.GetFullPathNameW(pathStart + startIndex, outputBuffer.Capacity + 1, outputBuffer, IntPtr.Zero)) > outputBuffer.Capacity)
{
// Reported size (which does not include the null) is greater than the buffer size. Increase the capacity.
outputBuffer.Capacity = result;
}
if (result == 0)
{
// Failure, get the error and throw
int errorCode = Marshal.GetLastWin32Error();
if (errorCode == 0)
{
errorCode = Interop.mincore.Errors.ERROR_BAD_PATHNAME;
}
throw Win32Marshal.GetExceptionForWin32Error(errorCode, path);
}
}
return(outputBuffer);
}
private static string TryExpandShortFileName(StringBuffer outputBuffer, string originalPath)
{
// We guarantee we'll expand short names for paths that only partially exist. As such, we need to find the part of the path that actually does exist. To
// avoid allocating like crazy we'll create only one input array and modify the contents with embedded nulls.
Debug.Assert(!PathInternal.IsRelative(outputBuffer), "should have resolved by now");
Debug.Assert(!PathInternal.IsExtended(outputBuffer), "expanding short names expects normal paths");
// Add the extended prefix before expanding to allow growth over MAX_PATH
StringBuffer inputBuffer = null;
ulong rootLength = PathInternal.GetRootLength(outputBuffer);
bool isUnc = IsUnc(outputBuffer);
ulong rootDifference = GetInputBuffer(outputBuffer, isUnc, out inputBuffer);
rootLength += rootDifference;
ulong inputLength = inputBuffer.Length;
bool success = false;
ulong foundIndex = inputBuffer.Length - 1;
while (!success)
{
uint result = Interop.mincore.GetLongPathNameW(inputBuffer.GetHandle(), outputBuffer.GetHandle(), (uint)outputBuffer.CharCapacity);
// Replace any temporary null we added
if (inputBuffer[foundIndex] == '\0')
{
inputBuffer[foundIndex] = '\\';
}
if (result == 0)
{
// Look to see if we couldn't find the file
int error = Marshal.GetLastWin32Error();
if (error != Interop.mincore.Errors.ERROR_FILE_NOT_FOUND && error != Interop.mincore.Errors.ERROR_PATH_NOT_FOUND)
{
// Some other failure, give up
break;
}
// We couldn't find the path at the given index, start looking further back in the string.
foundIndex--;
for (; foundIndex > rootLength && inputBuffer[foundIndex] != '\\'; foundIndex--)
{
;
}
if (foundIndex == rootLength)
{
// Can't trim the path back any further
break;
}
else
{
// Temporarily set a null in the string to get Windows to look further up the path
inputBuffer[foundIndex] = '\0';
}
}
else if (result > outputBuffer.CharCapacity)
{
// Not enough space. The result count for this API does not include the null terminator.
outputBuffer.EnsureCharCapacity(result);
result = Interop.mincore.GetLongPathNameW(inputBuffer.GetHandle(), outputBuffer.GetHandle(), (uint)outputBuffer.CharCapacity);
}
else
{
// Found the path
success = true;
outputBuffer.Length = result;
if (foundIndex < inputLength - 1)
{
// It was a partial find, put the non-existant part of the path back
outputBuffer.Append(inputBuffer, foundIndex, inputBuffer.Length - foundIndex);
}
}
}
// Strip out the prefix and return the string
StringBuffer bufferToUse = success ? outputBuffer : inputBuffer;
string returnValue = null;
int newLength = (int)(bufferToUse.Length - rootDifference);
if (isUnc)
{
// Need to go from \\?\UNC\ to \\?\UN\\
bufferToUse[(ulong)PathInternal.UncExtendedPathPrefix.Length - 1] = '\\';
}
if (bufferToUse.SubstringEquals(originalPath, rootDifference, newLength))
{
// Use the original path to avoid allocating
returnValue = originalPath;
}
else
{
returnValue = bufferToUse.Substring(rootDifference, newLength);
}
inputBuffer.Dispose();
return(returnValue);
}
