Prevent Application Crash when Numeric Config Entries Contain Dynamic String Interpolations

[MadMartian]

I figured out how to run a separate instance of the visualizer on each screen by leveraging dynamic ${application.argv[n]} options in the projectMSDL.properties file, however this was causing the GUI to crash as it expects to read integer values for the screen, width, and height fields. This change prevents the GUI from crashing, ignores the setting, and logs a warning about the errant property.

There is also a change renaming a reference from a "device" property ⇒ "audio.device", this may be incorrect but the application seems to accept it and it's consistent with appearances of "audio.device" elsewhere in the repository.

This PR allows me to... (toggle pattern)

killall projectMSDL || (projectMSDL 1 2560 1440 & projectMSDL 2 1920 1080 & projectMSDL 3 1920 1080 &)

...with properties...

window.monitor = ${application.argv[1]}
window.width = ${application.argv[2]}
window.height = ${application.argv[3]}

Running 3 instances seems lightweight enough, my rig isn't even breaking a sweat at ~5% CPU usage, GPU load is ~35% on an RTX 3090.

[MadMartian]

I found references to "audio.device" elsewhere, so I presumed "device" was not correct.

[kblaschke]

It is correct, as the audio subsystem only gets a view of the audio config key, thus only the subkeys are used to access the data. See this line here:

frontend-sdl-cpp/src/AudioCapture.cpp

Line 20 in 9d93ead

_config = app.config().createView("audio");

[MadMartian]

Pass logger from parent

[kblaschke]

There is no need to pass loggers around. Each class creates its own Logger instance with a distinct name. If multiple instances of a class exist, they share the same instance.

See this example:

frontend-sdl-cpp/src/AudioCapture.h

Line 87 in 9d93ead

Poco::Logger& _logger{ Poco::Logger::get("AudioCapture") }; //!< The class logger.

[kblaschke]

Loggers can also have hierarchical names, e.g. GUI.SettingsWindow. In larger applications, this makes it possible to set specific logging options for a whole subsystem, as all loggers under GUI would get the same config if you set it for this path.

I'd recommend reading the documentation on loggers, subsystems and applications on pocoproject.com, it's quite sophisticated.

[kblaschke]

In this case, the logger in the SettingsWindow class should be declared in the header as:

    Poco::Logger& _logger{ Poco::Logger::get("SettingsWindow") }; //!< The class logger. 

You can then refer to it as usual.

[MadMartian]

This gets called repeatedly, so it was necessary to leverage some mechanism to keep track of the syntax exceptions in order to suppress successive warnings.

[kblaschke]

I don't think such a complex logic is necessary here. If a user really messes up the value, use the default and if the user saves it, just save the default value. Logging the syntax error should be enough, as is the warning level.

IMO this is basically the same as just removing the setting from the file, which is also a valid thing to do.

[MadMartian]

NOTE: Changing field order might introduce some unintended side-effects, depending on the compiler.

[kblaschke]

Instead of this "_safeInt" function, it'd be way easier to simply catch the exception and use the default values if something is wrong, like this:

    int values[2];
    try
    {
        values[0] = _userConfiguration->getInt(property1, defaultValue1);
        values[1] = _userConfiguration->getInt(property2, defaultValue2);
    }
    catch (Poco::SyntaxException&)
    {
        values[0] = defaultValue1;
        values[1] = defaultValue2;
    }

This will also make sure that both values are using the default if any property fails, and not an undefined mix of both.
Initialization isn't strictly necessary because either code path sets both values if successful.

[kblaschke]

In this case, the logger in the SettingsWindow class should be declared in the header as:

    Poco::Logger& _logger{ Poco::Logger::get("SettingsWindow") }; //!< The class logger. 

You can then refer to it as usual.

[kblaschke]

Suggested change

	std::set<std::string> _suppressPropertyWarnings;
	Poco::Logger & _logger;
	Poco::Logger& _logger{ Poco::Logger::get("SettingsWindow") }; //!< The class logger.