/// <summary>
/// Changes the request header set on the ELM327.
/// </summary>
/// <param name="header">Request header to set.</param>
/// <returns>True if successful; otherwise, false.</returns>
protected bool SetRequestHeader(string header)
{
string response = String.Empty;
// Request the Semaphore
ConnectionSemaphore.WaitOne();
// Set header
response = ExecuteATCommand(@"SH" + header);
// If we were not successful at setting the header, quit.
if (!(response.Equals("OK")))
{
log.Error("Attempt at Set Headers [AT SH " + header + "] failed. Response: " + response.ToString());
ConnectionSemaphore.Release();
return(false);
}
// Release the Semaphore
ConnectionSemaphore.Release();
return(true);
}
/// <summary>
/// Executes one request/response cycle on the port set as this Protocol's connection.
/// </summary>
/// <param name="handler">The handler for whom the request response cycle is handled for.</param>
/// <returns>True if the execution was successful; otherwise, false.</returns>
public unsafe override bool Execute(IHandler handler)
{
// Variables
uint idBuffer = 0x00000000;
uint pciBuffer = 0x00000000;
bool returnValue = true;
string tempString;
// Single Frame Data Buffer
byte[] parsingBuffer;
byte[] multiframeDataBuffer;
/*
* -- STEPS --
* 1. Set/Clear Headers
* 2. Transmit request
* 3. Process responses
*/
// Reset our stopwatch
CurrentRunningTime = 0;
stopwatch.Reset();
// Reset stop execution flag
StopExecution = false;
// If no ECU filter is set and this handler requires custom headers, let's take care of that
if (SelectedEcuFilter == Global.Constants.NoSelection && handler.IsCustomHeader)
{
// Only set the custom header if it is not already set
if (!(_lastUsedHeader.Equals(handler.Header)))
{
if (!SetRequestHeader(handler.Header))
{
return(false);
}
_lastUsedHeader.Clear().Append(handler.Header);
}
}
// If no custom handler is required or an ECU filter is selected...
else
{
// If an ECU filter is selected, apply it if necessary
if (SelectedEcuFilter != Global.Constants.NoSelection)
{
// Skip this if we're debugging (the emulator doesn't handle the AT SH command)
#if !DEBUG
if (!(_lastUsedHeader.ToString().Equals(SelectedEcuFilter.RequestAddressString)))
{
if (!SetRequestHeader(SelectedEcuFilter.RequestAddressString))
{
return(false);
}
_lastUsedHeader.Clear().Append(SelectedEcuFilter.RequestAddressString);
}
#endif
}
// If no ECU filter is applied and this handler does not require custom headers,
// but the last handler did, we MUST clear the custom headers out of the ELM 327 device.
else if (!(_lastUsedHeader.ToString().Equals("")))
{
if (!SetRequestHeader(EcuAddresses[0].RequestAddressString))
{
return(false);
}
_lastUsedHeader.Clear();
_incomingResponseBuffer.Clear();
}
}
// Transmit the request
ConnectionSemaphore.WaitOne();
Connection.DiscardInBuffer();
Connection.DiscardOutBuffer();
ExecuteCommand(handler.Request);
// Do we expect a response?
if (handler.ExpectsResponse)
{
// Begin listening
_hasMoreResponses = true;
try
{
stopwatch.Start();
while (_hasMoreResponses && !(StopExecution))
{
// Clear the buffer
_incomingResponseBuffer.Clear();
// Grab the incoming message
_incomingResponseBuffer.Append(Connection.ReadLine());
// Verify a line was received
if (_incomingResponseBuffer.Length < 1)
{
continue;
}
// Remove the prompt if it exists
if (_incomingResponseBuffer[0] == '>')
{
_incomingResponseBuffer.Remove(0, 1);
}
// Ensure an error was not received
tempString = _incomingResponseBuffer.ToString();
if (tempString.Equals(Global.Constants.STOPPED_MESSAGE) || tempString.Equals(Global.Constants.NO_DATA_MESSAGE) || tempString.Equals(Global.Constants.SEARCHING_MESSAGE) || tempString.Equals(Global.Constants.UNABLE_TO_CONNECT_MESSAGE))
{
continue;
}
// Convert the hex string to actual bits
parsingBuffer = Utility.HexStringToByteArray(tempString);
fixed(byte *p1 = parsingBuffer)
{
// Get the CAN ID (we grab 12 bits to compare the 3 hex characters -- note, the last bit is always 0)
idBuffer = (uint)(((parsingBuffer[0] << 8) | parsingBuffer[1]) & BITMASK_ID) >> 4;
// Get the PCI Code
pciBuffer = (uint)parsingBuffer[1] & BITMASK_PCITYPE;
// If an ECU filter is set, confirm the idBuffer equals the ECU's Return Address
if (SelectedEcuFilter != Global.Constants.NoSelection && idBuffer != SelectedEcuFilter.ReturnAddress)
{
log.Error("Filtering for [" + SelectedEcuFilter.ReturnAddressString + "]. Message from [" + idBuffer.ToString("X6") + "] rejected.");
returnValue = false;
break;
}
switch (pciBuffer)
{
case (uint)FrameTypes.SINGLE_FRAME:
{
try
{
// Send the data payload to the handler
handler.ProcessResponse(
ProcessSingleFrameResponse(handler, parsingBuffer)
);
// Exit gracefully
_hasMoreResponses = false;
}
catch (ProtocolProcessingException e)
{
log.Error("Single Frame Processing Exception Occurred for [" + handler.Name + ":" + handler.Request + "]:", e);
returnValue = false;
}
break;
}
case (uint)FrameTypes.FIRST_FRAME:
{
try
{
// Process the First Frame. The data bytes and other session information
// for this multiframe response will be stored in the _responseBuffer.
ProcessFirstFrameResponse(idBuffer, handler, parsingBuffer);
}
catch (ProtocolProcessingException e)
{
log.Error("First Frame Processing Exception Occurred for [" + handler.Name + ":" + handler.Request + "]:", e);
// Cancel this Request/Response Cycle
_responseBuffer.Remove(idBuffer);
returnValue = false;
}
break;
}
case (uint)FrameTypes.CONSECUTIVE_FRAME:
{
try
{
// Process this frame
multiframeDataBuffer = ProcessConsecutiveFrameResponse(idBuffer, handler, parsingBuffer);
// We're done, so let's deliver the data to the interested Handler
if (multiframeDataBuffer != null)
{
// Send the data to the handler
handler.ProcessResponse(multiframeDataBuffer);
// Remove this response from the response buffer
_responseBuffer.Remove(idBuffer);
}
}
catch (Exception e)
{
log.Error("Consecutive Frame Processing Exception Occurred for [" + handler.Name + ":" + handler.Request + "]:", e);
// Cancel this Request/Response Cycle
_responseBuffer.Remove(idBuffer);
returnValue = false;
}
break;
}
}
}
// Update the running time
CurrentRunningTime = stopwatch.ElapsedMilliseconds;
// Check if we need to continue listening
if (_responseBuffer.Count == 0)
{
_hasMoreResponses = false;
}
// Clear the buffer to try again
_incomingResponseBuffer.Clear();
}
}
catch (Exception e)
{
log.Error("Exception occurred while reading responses for [" + handler.Name + ":" + handler.Request + "]: " + e.Message);
returnValue = false;
}
// Stop the stopwatch, clear the current running time, and broadcast the response time
stopwatch.Stop();
CurrentRunningTime = 0;
if (BroadcastResponseTime != null)
{
BroadcastResponseTime(stopwatch.ElapsedMilliseconds);
}
}
// Release the Semaphore
ConnectionSemaphore.Release();
return(returnValue);
}
