/// <summary>
/// Perform a USB control transfer for multi-threaded applications using the <see cref="LibUsbEventHandler"/> class.
/// </summary>
/// <remarks>
/// <para>The direction of the transfer is inferred from the bmRequestType field of the setup packet.</para>
/// <para>The wValue, wIndex and wLength fields values should be given in host-endian byte order.</para>
/// <note type="tip" title="Libusb-1.0 API:"><seelibusb10 group="syncio"/></note>
/// </remarks>
/// <param name="deviceHandle">A handle for the device to communicate with.</param>
/// <param name="requestType">The request type field for the setup packet.</param>
/// <param name="request">The request field for the setup packet.</param>
/// <param name="value">The value field for the setup packet</param>
/// <param name="index">The index field for the setup packet.</param>
/// <param name="pData">A suitably-sized data buffer for either input or output (depending on direction bits within bmRequestType).</param>
/// <param name="dataLength">The length field for the setup packet. The data buffer should be at least this size.</param>
/// <param name="timeout">timeout (in milliseconds) that this function should wait before giving up due to no response being received. For an unlimited timeout, use value 0.</param>
/// <returns>
/// <list type="bullet">
/// <item>on success, the number of bytes actually transferred</item>
/// <item><see cref="LibUsbError.ErrorTimeout"/> if the transfer timed out</item>
/// <item><see cref="LibUsbError.ErrorPipe"/> if the control request was not supported by the device.</item>
/// <item><see cref="LibUsbError.ErrorNoDevice"/> if the device has been disconnected</item>
/// <item>another <see cref="LibUsbError"/> code on other failures</item>
/// </list>
/// </returns>
public static int ControlTransferAsync([In] LibUsbDeviceHandle deviceHandle,
byte requestType,
byte request,
short value,
short index,
IntPtr pData,
short dataLength,
int timeout)
{
LibUsbControlSetupHandle setupHandle = new LibUsbControlSetupHandle(requestType, request, value, index, pData, dataLength);
LibUsbTransfer transfer = new LibUsbTransfer(0);
ManualResetEvent completeEvent = new ManualResetEvent(false);
GCHandle gcCompleteEvent = GCHandle.Alloc(completeEvent);
transfer.FillControl(deviceHandle, setupHandle, DefaultAsyncDelegate, GCHandle.ToIntPtr(gcCompleteEvent), timeout);
int r = (int)transfer.Submit();
if (r < 0)
{
transfer.Free();
gcCompleteEvent.Free();
return r;
}
IntPtr pSessionHandle;
LibUsbSessionHandle sessionHandle = LibUsbEventHandler.SessionHandle;
if (sessionHandle == null)
pSessionHandle = IntPtr.Zero;
else
pSessionHandle = sessionHandle.DangerousGetHandle();
if (LibUsbEventHandler.IsStopped)
{
while (!completeEvent.WaitOne(0, false))
{
r = HandleEvents(pSessionHandle);
if (r < 0)
{
if (r == (int)LibUsbError.ErrorInterrupted)
continue;
transfer.Cancel();
while (!completeEvent.WaitOne(0, false))
if (HandleEvents(pSessionHandle) < 0)
break;
transfer.Free();
gcCompleteEvent.Free();
return r;
}
}
}
else
{
completeEvent.WaitOne(Timeout.Infinite, UsbConstants.EXIT_CONTEXT);
}
if (transfer.Status == LibUsbTansferStatus.TransferCompleted)
{
r = transfer.ActualLength;
if (r > 0)
{
byte[] ctrlDataBytes = setupHandle.ControlSetup.GetData(r);
Marshal.Copy(ctrlDataBytes, 0, pData, Math.Min(ctrlDataBytes.Length, dataLength));
}
}
else
r = (int)MonoLibUsbErrorFromTransferStatus(transfer.Status);
transfer.Free();
gcCompleteEvent.Free();
return r;
}
/// <summary>
/// Helper function to populate the required <see cref="LibUsbTransfer"/> properties for a control transfer.
/// </summary>
/// <remarks>
/// <note type="tip">
/// <para>Isochronous transfers are not supported on windows.</para>
/// </note>
/// <note title="Libusb-1.0 API Note:" type="cpp">
/// <see cref="FillControl"/> is similar to
/// <a href="http://libusb.sourceforge.net/api-1.0/group__asyncio.html#ga3a8513ed87229fe2c9771ef0bf17206e">libusb_fill_control_transfer()</a>.
/// </note>
/// </remarks>
/// <param name="devHandle">handle of the device that will handle the transfer</param>
/// <param name="controlSetupHandle">the setup packet/control data to transfer.</param>
/// <param name="callback">callback function to be invoked on transfer completion</param>
/// <param name="userData">user data to pass to callback function</param>
/// <param name="timeout">timeout for the transfer in milliseconds</param>
public void FillControl(LibUsbDeviceHandle devHandle, LibUsbControlSetupHandle controlSetupHandle, Delegate callback, IntPtr userData, int timeout)
{
PtrDeviceHandle = devHandle.DangerousGetHandle();
Endpoint = 0;
PtrCallbackFn = Marshal.GetFunctionPointerForDelegate(callback);
PtrUserData = userData;
Timeout = timeout;
Type = EndpointType.Control;
Flags = LibUsbTransferFlags.None;
IntPtr pSetupPacket = controlSetupHandle.DangerousGetHandle();
PtrBuffer = pSetupPacket;
LibUsbControlSetup w = new LibUsbControlSetup(pSetupPacket);
Length = LibUsbControlSetup.SETUP_PACKET_SIZE + w.Length;
}
