private unsafe void HandleOverlappedAPI(bool success, string errorMessage, NativeOverlapped *pOverlapped,
USBAsyncResult result, int bytesTransfered)
{
if (!success)
{
if (Marshal.GetLastWin32Error() != Kernel32.ERROR_IO_PENDING)
{
Overlapped.Unpack(pOverlapped);
Overlapped.Free(pOverlapped);
throw new Exception(errorMessage);
}
}
else
{
// Immediate success!
Overlapped.Unpack(pOverlapped);
Overlapped.Free(pOverlapped);
result.OnCompletion(true, null, bytesTransfered, false);
// is the callback still called in this case?? todo
}
}
private IAsyncResult BeginWrite(byte endpoint, byte[] buffer, int length, AsyncCallback userCallback,
object stateObject)
{
var result = new USBAsyncResult(userCallback, stateObject);
try
{
var overlapped = new Overlapped();
overlapped.AsyncResult = result;
unsafe
{
NativeOverlapped *pOverlapped = null;
int bytesWritten;
pOverlapped = overlapped.Pack(PipeIOCallback, buffer);
bool success;
// Buffer is pinned already by overlapped.Pack
fixed(byte *pBuffer = buffer)
{
success = WinUsb.NativeMethods.WinUsb_WritePipe(winUsbHandle, endpoint, buffer, length,
out bytesWritten, (IntPtr)pOverlapped);
}
HandleOverlappedAPI(success, "Failed to asynchronously write pipe on WinUSB device.", pOverlapped,
result, bytesWritten);
}
}
catch (Exception e)
{
if (result != null)
{
result.Dispose();
}
Close(); // Transfer exceptions are fatal; close the connection.
}
return(result);
}
private IAsyncResult BeginRead(byte endpoint, byte[] buffer, int length, AsyncCallback userCallback,
object stateObject)
{
var result = new USBAsyncResult(userCallback, stateObject);
try
{
var overlapped = new Overlapped();
overlapped.AsyncResult = result;
unsafe
{
NativeOverlapped *pOverlapped = null;
int bytesRead;
pOverlapped = overlapped.Pack(PipeIOCallback, buffer);
bool success;
// Buffer is pinned already by overlapped.Pack
success = WinUsb.NativeMethods.WinUsb_ReadPipe(winUsbHandle, endpoint, buffer, length,
out bytesRead, (IntPtr)pOverlapped);
HandleOverlappedAPI(success, "Failed to asynchronously read pipe on WinUSB device.", pOverlapped,
result, bytesRead);
}
}
catch (Exception e)
{
if (result != null)
{
result.Dispose();
}
throw new Exception("Failed to read from pipe.", e);
}
return(result);
}