toys/usb/source/enum_serial_port.cpp

#if defined(OS_WINDOWS)

struct SSerInfo {
    CString strDevPath;          // Device path for use with CreateFile()
    CString strPortName;         // Simple name (i.e. COM1)
    CString strFriendlyName;     // Full name to be displayed to a user
    CString strPortDesc;         // friendly name without the COMx
};


void EnumSerialPorts(CArray<SSerInfo,SSerInfo&> &asi, BOOL bIgnoreBusyPorts)
{
	// Clear the output array
	asi.RemoveAll();
	EnumPortsWdm(asi);

	for (int ii=0; ii<asi.GetSize(); ii++)
	{
		SSerInfo& rsi = asi[ii];    
		if (bIgnoreBusyPorts) {
			// Only display ports that can be opened for read/write
			HANDLE hCom = CreateFile(rsi.strDevPath,
				GENERIC_READ | GENERIC_WRITE,
				0,    /* comm devices must be opened w/exclusive-access */
				NULL, /* no security attrs */
				OPEN_EXISTING, /* comm devices must use OPEN_EXISTING */
				0,    /* not overlapped I/O */
				NULL  /* hTemplate must be NULL for comm devices */
				);
			if (hCom == INVALID_HANDLE_VALUE) {
				// It can't be opened; remove it.
				asi.RemoveAt(ii);
				ii--;               
				continue;
			}
			else {
				// It can be opened! Close it and add it to the list
				::CloseHandle(hCom);
			}
		}

		if (rsi.strFriendlyName.IsEmpty())
		{
			asi.RemoveAt(ii);
			ii--;               
			continue;
		}

		CString fName = rsi.strFriendlyName;
		TCHAR *pt, *pt1;
		pt = fName.GetBuffer() + fName.GetLength() - 1;
		while (*pt != _T('('))
		{
			pt --;
		}
		if (_tcsncmp(pt, _T("(COM"), 4))
		{
			asi.RemoveAt(ii);
			ii--;               
			continue;
		}
		rsi.strPortName.Empty();
		rsi.strPortName = _T("COM");
		pt1 = pt + 4;
		while ((*pt1>=_T('0')) && (*pt1<=_T('9')))
		{
			rsi.strPortName += *pt1++;
		}

		pt -= 2;
		pt1 = fName.GetBuffer();
		rsi.strPortDesc.Empty();
		while (pt1 <= pt)
		{
			rsi.strPortDesc += *pt1++;
		}
	}
}

void EnumPortsWdm(CArray<SSerInfo,SSerInfo&> &asi)
{
	CString strErr;
	// Create a device information set that will be the container for 
	// the device interfaces.
	GUID *guidDev = (GUID*) &GUID_CLASS_COMPORT;

	HDEVINFO hDevInfo = INVALID_HANDLE_VALUE;
	SP_DEVICE_INTERFACE_DETAIL_DATA *pDetData = NULL;

	try {
		hDevInfo = SetupDiGetClassDevs( guidDev,
			NULL,
			NULL,
			DIGCF_PRESENT | DIGCF_DEVICEINTERFACE
			);

		if(hDevInfo == INVALID_HANDLE_VALUE) 
		{
			strErr.Format(_T("SetupDiGetClassDevs failed. (err=%lx)"),
				GetLastError());
			throw strErr;
		}

		// Enumerate the serial ports
		BOOL bOk = TRUE;
		SP_DEVICE_INTERFACE_DATA ifcData;
		DWORD dwDetDataSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA) + 256;
		pDetData = (SP_DEVICE_INTERFACE_DETAIL_DATA*) new char[dwDetDataSize];
		// This is required, according to the documentation. Yes,
		// it's weird.
		ifcData.cbSize = sizeof(SP_DEVICE_INTERFACE_DATA);
		pDetData->cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA);
		for (DWORD ii=0; bOk; ii++) {
			bOk = SetupDiEnumDeviceInterfaces(hDevInfo,
				NULL, guidDev, ii, &ifcData);
			if (bOk) {
				// Got a device. Get the details.
				SP_DEVINFO_DATA devdata = {sizeof(SP_DEVINFO_DATA)};
				bOk = SetupDiGetDeviceInterfaceDetail(hDevInfo,
					&ifcData, pDetData, dwDetDataSize, NULL, &devdata);
				if (bOk) {
					CString strDevPath(pDetData->DevicePath);
					// Got a path to the device. Try to get some more info.
					TCHAR fname[256];
					BOOL bSuccess = SetupDiGetDeviceRegistryProperty(
						hDevInfo, &devdata, SPDRP_FRIENDLYNAME, NULL,
						(PBYTE)fname, sizeof(fname), NULL);
					if (bSuccess) {
						// Add an entry to the array
						SSerInfo si;
						si.strDevPath = strDevPath;
						si.strFriendlyName = fname;
						asi.Add(si);
					}

				}
				else {
					strErr.Format(_T("SetupDiGetDeviceInterfaceDetail failed. (err=%lx)"),
						GetLastError());
					throw strErr;
				}
			}
			else {
				DWORD err = GetLastError();
				if (err != ERROR_NO_MORE_ITEMS) {
					strErr.Format(_T("SetupDiEnumDeviceInterfaces failed. (err=%lx)"), err);
					throw strErr;
				}
			}
		}
	}
	catch (CString strCatchErr) {
		strErr = strCatchErr;
	}

	if (pDetData != NULL)
		delete [] (char*)pDetData;

	if (hDevInfo != INVALID_HANDLE_VALUE)
		SetupDiDestroyDeviceInfoList(hDevInfo);

	if (!strErr.IsEmpty())
		throw strErr;
}
#endif /* OS_WINDOWS */