/// <summary>
/// Читает максимум один фрейм и возвращает управление. При этом сохраняет свое состояние и ждет повторного вызова
/// чтобы выкачать все сообщение.
/// </summary>
/// <exception cref="ASTMIOException">Любая ошибка упаковывается в этот класс как InnerException</exception>
/// <exception cref="TimeoutException">Тихо в лесу</exception>
public void ExecuteDownloadStep()
{
if (Completed)
{
throw new InvalidOperationException("Download has been completed already");
}
switch (_state)
{
case States.WaitEstablishmentPhase:
_stream.ReadTimeout = 100;
var b = (byte)_stream.ReadByte();
if (b == (byte)DataLinkControlCodes.ENQ)
{
_log.LogInformation($"[receive]{ControlCodesUtility.ToControlCode(b)}");
_stream.WriteByte((byte)DataLinkControlCodes.ACK);
_log.LogInformation($"[send]{ControlCodesUtility.ToControlCode((byte) DataLinkControlCodes.ACK)}");
_state = States.ReceiveFrame;
}
else
{
_log.LogDebug($"[receive]{(char) b}");
}
break;
case States.ReceiveFrame:
if (!_timersManager.IsTimerInStartedState(WAIT_FRAME_TIMER_NAME))
{
_timersManager.StartTimer(WAIT_FRAME_TIMER_NAME, _lowLevelSettings.WaitFrameTimeout);
}
try
{
_stream.ReadTimeout = 100;
b = (byte)_stream.ReadByte();
if (b == (byte)DataLinkControlCodes.EOT)
{
_timersManager.StopTimer(WAIT_FRAME_TIMER_NAME);
_log.LogInformation("[receive]{0}", ControlCodesUtility.ToControlCode(b));
_state = States.Completed;
_completed = true;
break;
}
_buf.Add(b);
if (b == (byte)DataLinkControlCodes.LF)
{
ProcessReceivedFrame();
_timersManager.StopTimer(WAIT_FRAME_TIMER_NAME);
}
_state = States.ReceiveFrame;
}
catch (TimeoutException timeoutException)
{
if (_timersManager.CheckTimerTimeout(WAIT_FRAME_TIMER_NAME))
{
throw new DataLinkLayerException(timeoutException, "Wait frame timeout");
}
}
break;
case States.Completed:
throw new InvalidOperationException("Download has been completed already");
}
}
/// <summary>
/// Закачивает максимум один фрейм и возвращает управление. При этом сохраняет свое состояние и ждет повторного вызова,
/// для того что бы закончить upload.
/// </summary>
/// <exception cref="UploadException">Выгрузка прервана из-за ошибок</exception>
/// <exception cref="InvalidOperationException">Выгрузка уже закончена</exception>
public void ExecuteUploadStep()
{
byte[] buf = null;
if (Completed)
{
throw new InvalidOperationException("Upload has been completed already");
}
if (!_timersManager.CheckTimerTimeout(WAIT_DELAY_TIMER_NAME))
{
return;
}
switch (_state)
{
case States.EstablishmentPhaseBegin:
_stream.WriteByte((byte)DataLinkControlCodes.ENQ);
_log.LogInformation("[send]{0}", ControlCodesUtility.ToControlCode((byte)DataLinkControlCodes.ENQ));
_timersManager.StartTimer(WAIT_ANSWER_TIMER_NAME, _lowLevelSettings.EnqWaitTimeout);
_state = States.EstablishmentPhaseWaitAnswer;
break;
case States.EstablishmentPhaseWaitAnswer:
try
{
_stream.ReadTimeout = 100;
var b = (byte)_stream.ReadByte();
_timersManager.StopTimer(WAIT_ANSWER_TIMER_NAME);
_log.LogInformation("[receive]{0}", ControlCodesUtility.ToControlCode(b));
if (b == (byte)DataLinkControlCodes.ACK)
{
_state = States.TransferPhaseSendFrame;
}
else if (b == (byte)DataLinkControlCodes.ENQ)
{
if (_havePriority)
{
_errorCounterENQ++;
if (_errorCounterENQ >= 2)
{
throw new DataLinkLayerException(new UnexpectedENQException(), "Remote system is stupid cow");
}
_timersManager.StartTimer(WAIT_DELAY_TIMER_NAME, 1000);
_state = States.EstablishmentPhaseBegin;
}
else
{
throw new DataLinkLayerException(new ContentionErrorException(), "Contention error occured");
}
}
else if (b == (byte)DataLinkControlCodes.NAK)
{
_errorCounterNAK++;
if (_errorCounterNAK >= 6)
{
_exceptionOccured = new DataLinkLayerException(new BusyException(), "Remote system busy while Establishment Phase");
_state = States.TerminationPhase;
}
else
{
_state = States.EstablishmentPhaseBegin;
_timersManager.StartTimer(WAIT_DELAY_TIMER_NAME, 1000);
}
}
else
{
_exceptionOccured = new DataLinkLayerException(new DefectiveResponseException(), "Defective response error occured while Establishment Phase");
_state = States.TerminationPhase;
}
}
catch (TimeoutException timeoutException)
{
if (_timersManager.CheckTimerTimeout(WAIT_ANSWER_TIMER_NAME))
{
_exceptionOccured = new DataLinkLayerException(timeoutException, "Remote device doesn't response while Establishment Phase");
_state = States.TerminationPhase;
}
}
break;
case States.TransferPhaseSendFrame:
_errorCounterDefective = 0;
_errorCounterNAK = 0;
_frameCounter++;
if (_frameCounter >= _frames.Length)
{
_state = States.TerminationPhase;
break;
}
_currentFrame = _frames[_frameCounter];
buf = Encoding.ASCII.GetBytes(_currentFrame.ToString());
_stream.Write(buf, 0, buf.Length);
_log.LogInformation("[send]{0}", ControlCodesUtility.ReplaceControlCodesToLoggingCodes(_currentFrame.ToString()));
_timersManager.StartTimer(WAIT_ANSWER_TIMER_NAME, 15000);
_state = States.TransferPhaseWaitAnswer;
break;
case States.TransferPhaseResendFrame:
buf = Encoding.ASCII.GetBytes(_currentFrame.ToString());
_stream.Write(buf, 0, buf.Length);
_log.LogInformation("[send]{0}", ControlCodesUtility.ReplaceControlCodesToLoggingCodes(_currentFrame.ToString()));
_timersManager.StartTimer(WAIT_ANSWER_TIMER_NAME, 15000);
_state = States.TransferPhaseWaitAnswer;
break;
case States.TransferPhaseWaitAnswer:
try
{
_stream.ReadTimeout = 100;
var b = (byte)_stream.ReadByte();
_timersManager.StopTimer(WAIT_ANSWER_TIMER_NAME);
_log.LogInformation("[receive]{0}", ControlCodesUtility.ToControlCode(b));
if (b == (byte)DataLinkControlCodes.ACK)
{
_state = States.TransferPhaseSendFrame;
}
else if (b == (byte)DataLinkControlCodes.NAK || b == (byte)DataLinkControlCodes.EOT)
{
_errorCounterNAK++;
if (_errorCounterNAK >= 6)
{
_state = States.TerminationPhase;
_exceptionOccured = new DataLinkLayerException(new BusyException(), "Remote system busy while Transfer Phase");
}
else
{
_state = States.TransferPhaseResendFrame;
_timersManager.StartTimer(WAIT_DELAY_TIMER_NAME, 10000);
}
}
else
{
_errorCounterDefective++;
if (_errorCounterDefective >= 6)
{
_state = States.TerminationPhase;
_exceptionOccured = new DataLinkLayerException(new DefectiveResponseException(), "Remote system response defective while Transfer Phase");
}
else
{
_state = States.TransferPhaseResendFrame;
}
}
}
catch (TimeoutException timeoutException)
{
if (_timersManager.CheckTimerTimeout(WAIT_ANSWER_TIMER_NAME))
{
_state = States.TerminationPhase;
_exceptionOccured = new DataLinkLayerException(timeoutException, "Remote device doesn't response while Transfer Phase");
}
}
break;
case States.TerminationPhase:
_stream.WriteByte((byte)DataLinkControlCodes.EOT);
_log.LogInformation("[send]{0}", ControlCodesUtility.ToControlCode((byte)DataLinkControlCodes.EOT));
if (_exceptionOccured != null)
{
throw _exceptionOccured;
}
else
{
_uploadCompleted = true;
}
break;
}
}