public static char GetFreeDriveLetter(bool getLastAvailable)
{
IEnumerable <char> freeDriveLetters = "CDEFGHIJKLMNOPQRSTUVWXYZ".Except(Directory.EnumerateLogicalDrivesInternal(false, false).Select(d => d.Name[0]));
try
{
return(getLastAvailable ? freeDriveLetters.Last() : freeDriveLetters.First());
}
catch
{
throw new Exception("There are no drive letters available.");
}
}
private static string DosDeviceToDosPath(string dosDevice, string deviceReplacement)
{
if (Utils.IsNullOrWhiteSpace(dosDevice))
{
return(string.Empty);
}
foreach (string drive in Directory.EnumerateLogicalDrivesInternal(false, false).Select(drv => drv.Name))
{
try
{
string path = RemoveTrailingDirectorySeparator(drive, false);
foreach (string devNt in Volume.QueryDosDevice(path).Where(dosDevice.StartsWith))
{
return(dosDevice.Replace(devNt, deviceReplacement ?? path));
}
}
catch
{
}
}
return(string.Empty);
}
internal static string GetFinalPathNameByHandleInternal(SafeFileHandle handle, FinalPathFormats finalPath)
{
NativeMethods.IsValidHandle(handle);
var buffer = new StringBuilder(NativeMethods.MaxPathUnicode);
// ChangeErrorMode is for the Win32 SetThreadErrorMode() method, used to suppress possible pop-ups.
using (new NativeMethods.ChangeErrorMode(NativeMethods.ErrorMode.FailCriticalErrors))
{
if (NativeMethods.IsAtLeastWindowsVista)
{
if (NativeMethods.GetFinalPathNameByHandle(handle, buffer, (uint)buffer.Capacity, finalPath) == Win32Errors.ERROR_SUCCESS)
{
NativeError.ThrowException(Marshal.GetLastWin32Error());
}
return(buffer.ToString());
}
}
#region 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 (SafeFileHandle handle2 = NativeMethods.CreateFileMapping(handle, null, 2, 0, 1, null))
{
NativeMethods.IsValidHandle(handle, Marshal.GetLastWin32Error());
// FILE_MAP_READ
// Read = 4
using (SafeLocalMemoryBufferHandle 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"
string 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:
string dosPath = DosDeviceToDosPath(dosDevice, null);
if (!Utils.IsNullOrWhiteSpace(dosPath))
{
string path = GetSuffixedDirectoryNameWithoutRootInternal(null, dosPath);
string driveLetter = RemoveTrailingDirectorySeparator(GetPathRoot(dosPath, false), false);
string file = GetFileName(dosPath, true);
if (!Utils.IsNullOrWhiteSpace(file))
{
foreach (string drive in Directory.EnumerateLogicalDrivesInternal(false, false).Select(drv => drv.Name).Where(drv => driveLetter.Equals(RemoveTrailingDirectorySeparator(drv, false), StringComparison.OrdinalIgnoreCase)))
{
return(CombineInternal(false, Volume.GetUniqueVolumeNameForPath(drive), path, file));
}
}
}
break;
}
// To: "\\?\C:\path\filename.ext"
return(Utils.IsNullOrWhiteSpace(dosDevice)
? string.Empty
: LongPathPrefix + DosDeviceToDosPath(dosDevice, null));
#endregion // Older OperatingSystem
}
public static IEnumerable <DriveInfo> EnumerateDrives(bool fromEnvironment, bool isReady)
{
return(Directory.EnumerateLogicalDrivesInternal(fromEnvironment, isReady));
}
public static DriveInfo[] GetDrives()
{
return(Directory.EnumerateLogicalDrivesInternal(false, false).ToArray());
}
