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implement SerialImpl::waitReadable on windows

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Add a  FILE_FLAG_OVERLAPPED flag when open the port
Revise the Read and Write method to support Asynchronous I/O
This commit is contained in:
X.F.Zhou 2022-07-18 21:56:15 +08:00
parent 7ca1d440fa
commit 21c6e32255
2 changed files with 61 additions and 11 deletions
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1
include/serial/impl/win.h
View File

@ -198,6 +198,7 @@ private:
HANDLE read_mutex;
// Mutex used to lock the write functions
HANDLE write_mutex;
OVERLAPPED overlapped_;
};
}

71
src/impl/win.cc
View File

@ -43,6 +43,8 @@ Serial::SerialImpl::SerialImpl (const string &port, unsigned long baudrate,
open ();
read_mutex = CreateMutex(NULL, false, NULL);
write_mutex = CreateMutex(NULL, false, NULL);
memset(&overlapped_, 0x00, sizeof(overlapped_));
overlapped_.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
}
Serial::SerialImpl::~SerialImpl ()
@ -50,6 +52,7 @@ Serial::SerialImpl::~SerialImpl ()
this->close();
CloseHandle(read_mutex);
CloseHandle(write_mutex);
CloseHandle(overlapped_.hEvent);
}
void
@ -70,7 +73,7 @@ Serial::SerialImpl::open ()
0,
0,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED,
0);
if (fd_ == INVALID_HANDLE_VALUE) {
@ -279,6 +282,8 @@ Serial::SerialImpl::close ()
{
if (is_open_ == true) {
if (fd_ != INVALID_HANDLE_VALUE) {
SetCommMask(fd_, 0);
ResetEvent(overlapped_.hEvent);
int ret;
ret = CloseHandle(fd_);
if (ret == 0) {
@ -315,9 +320,49 @@ Serial::SerialImpl::available ()
}
bool
Serial::SerialImpl::waitReadable (uint32_t /*timeout*/)
Serial::SerialImpl::waitReadable (uint32_t timeout)
{
THROW (IOException, "waitReadable is not implemented on Windows.");
COMSTAT cs;
DWORD error;
DWORD old_msk, msk, length;
if (!isOpen()) {
return false;
}
if (!GetCommMask(fd_, &old_msk)) {
stringstream ss;
ss << "Error while get mask of the serial port: " << GetLastError();
THROW(IOException, ss.str().c_str());
}
msk = 0;
SetCommMask(fd_, EV_RXCHAR | EV_ERR);
if (!WaitCommEvent(fd_, &msk, &overlapped_)) {
if (GetLastError() == ERROR_IO_PENDING) {
if (WaitForSingleObject(overlapped_.hEvent, (DWORD)timeout) == WAIT_TIMEOUT) {
SetCommMask(fd_, old_msk);
return false;
}
GetOverlappedResult(fd_, &overlapped_, &length, TRUE);
::ResetEvent(overlapped_.hEvent);
} else {
ClearCommError(fd_, &error, &cs);
SetCommMask(fd_, old_msk);
return cs.cbInQue > 0;
}
}
SetCommMask(fd_, old_msk);
if (msk & EV_ERR) {
ClearCommError(fd_, &error, &cs);
return cs.cbInQue > 0;
}
if (msk & EV_RXCHAR) {
return true;
}
return false;
}
@ -338,11 +383,13 @@ Serial::SerialImpl::read (uint8_t *buf, size_t size)
throw PortNotOpenedException ("Serial::read");
}
DWORD bytes_read;
if (!ReadFile(fd_, buf, static_cast<DWORD>(size), &bytes_read, NULL)) {
stringstream ss;
ss << "Error while reading from the serial port: " << GetLastError();
THROW (IOException, ss.str().c_str());
overlapped_.Offset = 0;
overlapped_.OffsetHigh = 0;
if (!ReadFile(fd_, buf, static_cast<DWORD>(size), NULL, &overlapped_)) {
WaitForSingleObject(overlapped_.hEvent, timeout_.read_timeout_constant);
}
GetOverlappedResult(fd_, &overlapped_, &bytes_read, TRUE);
::ResetEvent(overlapped_.hEvent);
return (size_t) (bytes_read);
}
@ -353,11 +400,13 @@ Serial::SerialImpl::write (const uint8_t *data, size_t length)
throw PortNotOpenedException ("Serial::write");
}
DWORD bytes_written;
if (!WriteFile(fd_, data, static_cast<DWORD>(length), &bytes_written, NULL)) {
stringstream ss;
ss << "Error while writing to the serial port: " << GetLastError();
THROW (IOException, ss.str().c_str());
overlapped_.Offset = 0;
overlapped_.OffsetHigh = 0;
if (!WriteFile(fd_, data, static_cast<DWORD>(length), NULL, &overlapped_)) {
WaitForSingleObject(overlapped_.hEvent, timeout_.write_timeout_constant);
}
GetOverlappedResult(fd_, &overlapped_, &bytes_written, TRUE);
::ResetEvent(overlapped_.hEvent);
return (size_t) (bytes_written);
}