/// <summary>
/// Get the list of data streams for the given handle.
/// </summary>
public static IEnumerable <StreamInformation> GetStreamInformationByHandle(SafeFileHandle fileHandle)
{
// https://msdn.microsoft.com/en-us/library/windows/desktop/aa364406.aspx
// typedef struct _FILE_STREAM_INFO
// {
// DWORD NextEntryOffset;
// DWORD StreamNameLength;
// LARGE_INTEGER StreamSize;
// LARGE_INTEGER StreamAllocationSize;
// WCHAR StreamName[1];
// } FILE_STREAM_INFO, *PFILE_STREAM_INFO;
return(BufferHelper.CachedInvoke <IEnumerable <StreamInformation>, HeapBuffer>((buffer) =>
{
unsafe
{
while (!Direct.GetFileInformationByHandleEx(fileHandle, FILE_INFO_BY_HANDLE_CLASS.FileStreamInfo,
buffer.VoidPointer, checked ((uint)buffer.ByteCapacity)))
{
WindowsError error = ErrorHelper.GetLastError();
switch (error)
{
case WindowsError.ERROR_HANDLE_EOF:
// No streams
return Enumerable.Empty <StreamInformation>();
case WindowsError.ERROR_MORE_DATA:
buffer.EnsureByteCapacity(buffer.ByteCapacity * 2);
break;
default:
throw ErrorHelper.GetIoExceptionForError(error);
}
}
}
var infos = new List <StreamInformation>();
var reader = new CheckedReader(buffer);
uint offset = 0;
do
{
reader.ByteOffset = offset;
offset = reader.ReadUint();
uint nameLength = reader.ReadUint();
infos.Add(new StreamInformation
{
Size = reader.ReadUlong(),
AllocationSize = reader.ReadUlong(),
Name = reader.ReadString((int)(nameLength / 2))
});
} while (offset != 0);
return infos;
}));
}
private static string GetFileInformationString(SafeFileHandle fileHandle, FILE_INFORMATION_CLASS fileInformationClass)
{
return(BufferHelper.CachedInvoke((StringBuffer buffer) =>
{
NTSTATUS status = NTSTATUS.STATUS_BUFFER_OVERFLOW;
uint nameLength = 260 * sizeof(char);
IO_STATUS_BLOCK ioStatus;
var reader = new CheckedReader(buffer);
while (status == NTSTATUS.STATUS_BUFFER_OVERFLOW)
{
// Add space for the FileNameLength
buffer.EnsureByteCapacity(nameLength + sizeof(uint));
unsafe
{
status = Direct.NtQueryInformationFile(
FileHandle: fileHandle,
IoStatusBlock: out ioStatus,
FileInformation: buffer.VoidPointer,
Length: checked ((uint)buffer.ByteCapacity),
FileInformationClass: fileInformationClass);
}
if (status == NTSTATUS.STATUS_SUCCESS || status == NTSTATUS.STATUS_BUFFER_OVERFLOW)
{
reader.ByteOffset = 0;
nameLength = reader.ReadUint();
}
}
if (status != NTSTATUS.STATUS_SUCCESS)
{
throw ErrorHelper.GetIoExceptionForNTStatus(status);
}
// The string isn't null terminated so we have to explicitly pass the size
return reader.ReadString(checked ((int)nameLength) / sizeof(char));
}));
}
/// <summary>
/// Gets the file name from the given handle. This uses GetFileInformationByHandleEx, which does not give back the drive
/// name for the path- but is available from Windows Store apps.
/// </summary>
public static string GetFileNameByHandle(SafeFileHandle fileHandle)
{
return(BufferHelper.CachedInvoke((HeapBuffer buffer) =>
{
unsafe
{
while (!Direct.GetFileInformationByHandleEx(
fileHandle, FILE_INFO_BY_HANDLE_CLASS.FileNameInfo,
buffer.VoidPointer,
checked ((uint)buffer.ByteCapacity)))
{
WindowsError error = ErrorHelper.GetLastError();
if (error != WindowsError.ERROR_MORE_DATA)
{
throw ErrorHelper.GetIoExceptionForError(error);
}
buffer.EnsureByteCapacity(buffer.ByteCapacity * 2);
}
}
var reader = new CheckedReader(buffer);
return reader.ReadString((int)(reader.ReadUint() / 2));
}));
}
