use QSerialPortInfo to detect presence of a serial port (fix #836)

[heikobihr]

Summary

• ProviderRs232: checking for existence of device file does not work on windows.

• instead: construct QSerialPortInfo from device name and check, if it is not null.

  When constructing QSerialPortInfo from device name, this constructor finds the
  relevant serial port among the available ones according to the port name name,
  and constructs the serial port info instance for that port.
  (https://doc.qt.io/qt-5/qserialportinfo.html#QSerialPortInfo-2)

Fixes: #836

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Docs
• Build-related changes
• Other, please describe:

If changing the UI of web configuration, please provide the before/after screenshot:

Does this PR introduce a breaking change? (check one)

• Yes
• No

If yes, please describe the impact and migration path for existing setups:

The PR fulfills these requirements:

• When resolving a specific issue, it's referenced in the PR's body (e.g. Fixes: #xxx[,#xxx], where "xxx" is the issue number)

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature
• Related documents have been updated (docs/docs/en)
• Related tests have been updated

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Other information:

[Lord-Grey]

Hi Heiko

Thanks for highlighting the difference between Linux and Windows, as well as the suggested solution.

Nevertheless, could you do me a favor and set the device in error with a failure text, if the device name is invalid, please?
i.e.

		if (!serialPortInfo.isNull())
		{
			...
		}
		else
		{
			QString errortext = QString("Invalid serial device name: [%1]!").arg(_deviceName);
			this->setInError(errortext);
			_preOpenDelayTimeOut = QDateTime::currentMSecsSinceEpoch() + _preOpenDelay;
			return false;
		}

Otherwise a user would wonder, why e.g. a non existing COM5 device is not working.

Thank you!

[hyperion-project]

Here is your new link to your workflow artifacts.

[Lord-Grey]

@heikobihr Thanks for the update.

I am currently in the process refactoring the Led-Devices's code which included the Rs232 one.
I have incorporated your input (plus some minor additions).

As it seems you have a serial device running with windows, would you mind testing my development branch from a Windows/Rs232 perspective?
That would be very much appreciated!

Many thanks in advance!

[heikobihr]

@Lord-Grey
Yes, I am running an adalight serial Port device with hyperion.ng on windows. I'll run a test of your development branch tonight.

[Paulchen-Panther]

I would like it if the available serial devices were transferred to the JsonAPI. With this one could create a drop down field in the WebUI and select connected devices. Examples can be found in the V4L2 Grabber.

QSerialPortInfo Enumerator Example

[Lord-Grey]

@Paulchen-Panther This is already available as part of my LedDevice Refactor Branch.
When I am back at my PC, I can quickly tell, how you could test it.
Edit: The backend implementation is available. The UI part is pending.

[heikobihr]

@Lord-Grey
I tested your LedDevice Refactor Branch, successfully. Hyperion.ng connects to my adalight and shows rainbow swirl startup effect.

[brindosch]

Thank you for contribution and testing.