private static byte GetCommandSuccess(INTV.Shared.Utility.ASCIIBinaryReader reader)
{
return(reader.ReadByte());
}
/// <summary>
/// Reads the response to a command - ACK, NAK, or other. See remarks.
/// </summary>
/// <param name="reader">The reader to use to get the response.</param>
/// <param name="command">The command that is executing.</param>
/// <param name="errorDetail">Receives detailed error information if the command is not acknowledged.</param>
/// <param name="timedOut">Receives a value indicating whether or not command execution timed out.</param>
/// <returns>The response, which could be Ack, Nak, or possibly another invalid value.</returns>
/// <remarks>From Joe's implementation of lc_wait_acknak:
/// This function is weird. It must consume some number of partial
/// beacons w/out advancing the CRC, and then an ACK/NAK. Only the ACK
/// advances the CRC. If we get an unexpected byte, for now just flag
/// an error.
/// To simplify things, this function does not update the CRC. The
/// caller should update the CRC.
/// </remarks>
private static byte GetCommandAcknowledgement(INTV.Shared.Utility.ASCIIBinaryReader reader, ProtocolCommandId command, ref string errorDetail, out bool timedOut)
{
byte result = 0xFF; // unknown state
timedOut = false;
#if false
try
{
do
{
result = reader.ReadByte();
} while (Device.BeaconCharacters.Contains((char)result));
}
catch (TimeoutException)
{
result = Nak;
}
#else
int state = -1;
var prevTimeout = reader.BaseStream.ReadTimeout;
if (reader.BaseStream.CanTimeout)
{
reader.BaseStream.ReadTimeout = 200;
}
try
{
const int RetryCount = 6;
for (int i = 0; i < RetryCount; ++i)
{
try
{
do
{
timedOut = false;
result = reader.ReadByte();
#if DEBUG
var forceNak = false;
switch (command)
{
case ProtocolCommandId.Ping:
case ProtocolCommandId.GarbageCollect:
// never inject a fake NAK for these
break;
default:
forceNak = ReturnNakForNextCommand;
break;
}
if (forceNak)
{
result = Nak;
}
#endif // DEBUG
if ((result == Ack) || (result == Nak))
{
i = RetryCount;
var errorMessage = "Command returned NAK directly on port getting command acknowledgement for: " + command + ", not 'virtual' Nak due to garbage.";
if (!string.IsNullOrEmpty(errorDetail))
{
errorDetail += Environment.NewLine;
}
errorDetail += errorMessage;
DebugOutputIf(result == Nak, errorMessage);
break;
}
if ((state == -1 || state == '\n') && result == 'L')
{
state = result;
}
else if ((state == -1 || state == 'L') && result == 'O')
{
state = result;
}
else if ((state == -1 || state == 'O') && result == 'C')
{
state = result;
}
else if ((state == -1 || state == 'C') && result == 'U')
{
state = result;
}
else if ((state == -1 || state == 'U') && result == 'T')
{
state = result;
}
else if ((state == -1 || state == 'T') && result == 'U')
{
state = result;
}
else if ((state == -1 || state == 'U') && result == 'S')
{
state = result;
}
else if ((state == -1 || state == 'S') && result == '\n')
{
state = result;
}
else
{
var errorMessage = "Unexpected response when executing command: " + command + ", returned: " + result;
if (!string.IsNullOrEmpty(errorDetail))
{
errorDetail += Environment.NewLine;
}
errorDetail += errorMessage;
DebugOutput(errorMessage);
state = -1;
i = RetryCount;
}
}while (Device.BeaconCharacters.Contains((char)state));
}
catch (TimeoutException)
{
var errorMessage = "Command response for: " + command + " timed out! Returning 'virtual' Nak";
errorDetail += errorMessage;
DebugOutput(errorMessage);
timedOut = true;
result = Nak;
}
}
}
finally
{
// reader.BaseStream may go bad if cord was pulled during communication.
if ((reader.BaseStream != null) && reader.BaseStream.CanTimeout)
{
reader.BaseStream.ReadTimeout = prevTimeout;
}
}
#endif // false
return(result);
}