internal static string GetFinalPathNameByHandleCore(SafeFileHandle handle, FinalPathFormats finalPath)
{
NativeMethods.IsValidHandle(handle);
var buffer = new StringBuilder(NativeMethods.MaxPathUnicode);
using (new NativeMethods.ChangeErrorMode(NativeMethods.ErrorMode.FailCriticalErrors))
{
if (NativeMethods.IsAtLeastWindowsVista)
{
// MSDN: GetFinalPathNameByHandle(): If the function fails for any other reason, the return value is zero.
var success = NativeMethods.GetFinalPathNameByHandle(handle, buffer, (uint)buffer.Capacity, finalPath) == Win32Errors.ERROR_SUCCESS;
var lastError = Marshal.GetLastWin32Error();
if (!success && lastError != Win32Errors.ERROR_SUCCESS)
{
NativeError.ThrowException(lastError);
}
return(buffer.ToString());
}
}
// Older OperatingSystem
// Obtaining a File Name From a File Handle
// http://msdn.microsoft.com/en-us/library/aa366789%28VS.85%29.aspx
// Be careful when using GetFileSizeEx to check the size of hFile handle of an unknown "File" type object.
// This is more towards returning a filename from a file handle. If the handle is a named pipe handle it seems to hang the thread.
// Check for: FileTypes.DiskFile
// Can't map a 0 byte file.
long fileSizeHi;
if (!NativeMethods.GetFileSizeEx(handle, out fileSizeHi))
{
if (fileSizeHi == 0)
{
return(string.Empty);
}
}
// PAGE_READONLY
// Allows views to be mapped for read-only or copy-on-write access. An attempt to write to a specific region results in an access violation.
// The file handle that the hFile parameter specifies must be created with the GENERIC_READ access right.
// PageReadOnly = 0x02,
using (var handle2 = NativeMethods.CreateFileMapping(handle, null, 2, 0, 1, null))
{
NativeMethods.IsValidHandle(handle, Marshal.GetLastWin32Error());
// FILE_MAP_READ
// Read = 4
using (var pMem = NativeMethods.MapViewOfFile(handle2, 4, 0, 0, (UIntPtr)1))
{
if (NativeMethods.IsValidHandle(pMem, Marshal.GetLastWin32Error()))
{
if (NativeMethods.GetMappedFileName(Process.GetCurrentProcess().Handle, pMem, buffer, (uint)buffer.Capacity))
{
NativeMethods.UnmapViewOfFile(pMem);
}
}
}
}
// Default output from GetMappedFileName(): "\Device\HarddiskVolumeX\path\filename.ext"
var dosDevice = buffer.Length > 0 ? buffer.ToString() : string.Empty;
// Select output format.
switch (finalPath)
{
// As-is: "\Device\HarddiskVolumeX\path\filename.ext"
case FinalPathFormats.VolumeNameNT:
return(dosDevice);
// To: "\path\filename.ext"
case FinalPathFormats.VolumeNameNone:
return(DosDeviceToDosPath(dosDevice, string.Empty));
// To: "\\?\Volume{GUID}\path\filename.ext"
case FinalPathFormats.VolumeNameGuid:
var dosPath = DosDeviceToDosPath(dosDevice, null);
if (!Utils.IsNullOrWhiteSpace(dosPath))
{
var driveLetter = RemoveTrailingDirectorySeparator(GetPathRoot(dosPath, false));
var file = GetFileName(dosPath, true);
if (!Utils.IsNullOrWhiteSpace(file))
{
foreach (var drive in Directory.EnumerateLogicalDrivesCore(false, false).Select(drv => drv.Name).Where(drv => driveLetter.Equals(RemoveTrailingDirectorySeparator(drv), StringComparison.OrdinalIgnoreCase)))
{
return(CombineCore(false, Volume.GetUniqueVolumeNameForPath(drive), GetSuffixedDirectoryNameWithoutRootCore(null, dosPath), file));
}
}
}
break;
}
// To: "\\?\C:\path\filename.ext"
return(!Utils.IsNullOrWhiteSpace(dosDevice) ? LongPathPrefix + DosDeviceToDosPath(dosDevice, null) : string.Empty);
}
