/*------------------------------------------------------------------------------
-- FUNCTION: PortIOThreadProc
--
-- DATE: Oct 13, 2010
--
-- REVISIONS: Nov 05, 2010
-- Modified the function to also listen for a "disconnect" event,
-- and to break in that case. ProcessRead() is now called once a
-- complete packet is confirmed (as opposed to sending the
-- contents of the buffer to ProcessRead() as soon as they arrive).
--
-- Nov 29, 2010
-- Renamed function from ReadThreadProc(). The event handling is
-- from the original function, but the response to each event has
-- changed.
--
-- DESIGNER: Dean Morin
--
-- PROGRAMMER: Dean Morin, Daniel Wright
--
-- INTERFACE: DWORD WINAPI PortIOThreadProc(HWND hWnd)
-- hWnd - the handle to the window
--
-- RETURNS: 0 because threads are required to return a DWORD.
--
-- NOTES:
-- While connected, this thread will loop and wait for characters
-- to arrive at the port, or for a timeout to occur, then call the
-- appropriate function. This function uses overlapped I/O.
------------------------------------------------------------------------------*/
DWORD WINAPI PortIOThreadProc(HWND hWnd) {
OVERLAPPED ol = {0};
DWORD dwEvent = 0;
DWORD dwError = 0;
COMSTAT cs = {0};
HANDLE* hEvents = NULL;
PSTATEINFO psi = NULL;
PWNDDATA pwd = (PWNDDATA) GetWindowLongPtr(hWnd, 0);
if ((ol.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL)) == NULL) {
DISPLAY_ERROR("Error creating event in read thread");
}
hEvents = (HANDLE*) malloc(sizeof(HANDLE) * PORT_IO_EVENTS);
hEvents[0] = CreateEvent(NULL, FALSE, FALSE, TEXT("disconnected"));
hEvents[1] = ol.hEvent;
psi = (PSTATEINFO) malloc(sizeof(STATEINFO));
InitStateInfo(psi);
DL_STATE = psi->iState;
while (pwd->bConnected) {
SetCommMask(pwd->hPort, EV_RXCHAR);
if (!WaitCommEvent(pwd->hPort, &dwEvent, &ol)) {
ProcessCommError(pwd->hPort);
}
dwEvent = WaitForMultipleObjects(PORT_IO_EVENTS, hEvents, FALSE,
psi->dwTimeout);
ClearCommError(pwd->hPort, &dwError, &cs);
if (dwEvent == WAIT_OBJECT_0) {
// the connection was severed
break;
}
else if (dwEvent == WAIT_OBJECT_0 + 1 && cs.cbInQue) {
// data arrived at the port
ReadFromPort(hWnd, psi, ol, cs.cbInQue);
}
else if (dwEvent == WAIT_TIMEOUT) {
// a timeout occured
ProcessTimeout(hWnd, psi);
}
else if (dwEvent == WAIT_FAILED) {
DISPLAY_ERROR("Invalid event occured in the Port I/O thread");
}
ResetEvent(ol.hEvent);
}
if (!PurgeComm(pwd->hPort, PURGE_RXCLEAR)) {
DISPLAY_ERROR("Error purging read buffer");
}
CloseHandle(ol.hEvent);
CloseHandle(hEvents[0]);
free(hEvents);
return 0;
}
status_t
LinkReceiver::GetNextMessage(int32 &code, bigtime_t timeout)
{
fReadError = B_OK;
int32 remaining = fDataSize - (fRecvStart + fReplySize);
STRACE(("info: LinkReceiver GetNextReply() reports %ld bytes remaining in buffer.\n", remaining));
// find the position of the next message header in the buffer
message_header *header;
if (remaining <= 0) {
status_t err = ReadFromPort(timeout);
if (err < B_OK)
return err;
remaining = fDataSize;
header = (message_header *)fRecvBuffer;
} else {
fRecvStart += fReplySize; // start of the next message
fRecvPosition = fRecvStart;
header = (message_header *)(fRecvBuffer + fRecvStart);
}
// check we have a well-formed message
if (remaining < (int32)sizeof(message_header)) {
// we don't have enough data for a complete header
STRACE(("error info: LinkReceiver remaining %ld bytes is less than header size.\n", remaining));
ResetBuffer();
return B_ERROR;
}
fReplySize = header->size;
if (fReplySize > remaining || fReplySize < (int32)sizeof(message_header)) {
STRACE(("error info: LinkReceiver message size of %ld bytes smaller than header size.\n", fReplySize));
ResetBuffer();
return B_ERROR;
}
code = header->code;
fRecvPosition += sizeof(message_header);
STRACE(("info: LinkReceiver got header %ld [%ld %ld %ld] from port %ld.\n",
header->code, fReplySize, header->code, header->flags, fReceivePort));
return B_OK;
}
