Streamline the handling of configurations

[dforsi]

This issue is for describing the state as of commit 75afe418c184e87aca65dd683144cb80e74fc9ec of 2024/05/12 and modify the code, the online manual, or just have a place to document it.

Configuration file written twice when exiting sdrangel

The file ~/.config/f4exb/SDRangel.conf is written twice on Linux in a short time because MainSettings::save is called twice when quitting sdrangel when clicking the X button or pressing Ctrl+Q:

1 MainSettings::save	mainsettings.cpp	173
2 MainWindow::closeEvent	mainwindow.cpp	1745
1 MainSettings::save	mainsettings.cpp	173
2 MainWindow::~MainWindow	mainwindow.cpp	322

This is unnecessary and wasteful. Issue #379 might be related.

Preferences::resetToDefaults called multiple times

Preferences::resetToDefaults is called 3 times when there is no configuration file (such as when sdrangel is run for the first time) and 2 times when there is a configuration file.

When there is no configuration:

1 Preferences::resetToDefaults	preferences.cpp	48
2 Preferences::Preferences	preferences.cpp	25
3 MainSettings::MainSettings	mainsettings.cpp	30
4 MainCore::MainCore	maincore.cpp	76
5 Holder::Holder	maincore.cpp	92
6 (anonymous namespace)::Q_QGS_mainCore::innerFunction	maincore.cpp	92
7 QGlobalStatic<MainCore, (anonymous namespace)::Q_QGS_mainCore::innerFunction, (anonymous namespace)::Q_QGS_mainCore::guard>::operator QGlobalStatic<MainCore, (anonymous namespace)::Q_QGS_mainCore::innerFunction, (anonymous namespace)::Q_QGS_mainCore::guard>::Type *	qglobalstatic.h	137
8 MainCore::instance	maincore.cpp	95
9 MainWindow::MainWindow	mainwindow.cpp	128
10 runQtApplication	main.cpp	196
11 main	main.cpp	248
1 Preferences::resetToDefaults	preferences.cpp	48
2 Preferences::Preferences	preferences.cpp	25
3 MainSettings::MainSettings	mainsettings.cpp	30
4 MainCore::MainCore	maincore.cpp	76
5 Holder::Holder	maincore.cpp	92
6 (anonymous namespace)::Q_QGS_mainCore::innerFunction	maincore.cpp	92
7 QGlobalStatic<MainCore, (anonymous namespace)::Q_QGS_mainCore::innerFunction, (anonymous namespace)::Q_QGS_mainCore::guard>::operator QGlobalStatic<MainCore, (anonymous namespace)::Q_QGS_mainCore::innerFunction, (anonymous namespace)::Q_QGS_mainCore::guard>::Type *	qglobalstatic.h	137
8 MainCore::instance	maincore.cpp	95
9 MainWindow::MainWindow	mainwindow.cpp	128
10 runQtApplication	main.cpp	196
11 main	main.cpp	248
1 Preferences::resetToDefaults	preferences.cpp	48
2 Preferences::Preferences	preferences.cpp	25
3 MainSettings::MainSettings	mainsettings.cpp	30
4 MainCore::MainCore	maincore.cpp	76
5 Holder::Holder	maincore.cpp	92
6 (anonymous namespace)::Q_QGS_mainCore::innerFunction	maincore.cpp	92
7 QGlobalStatic<MainCore, (anonymous namespace)::Q_QGS_mainCore::innerFunction, (anonymous namespace)::Q_QGS_mainCore::guard>::operator QGlobalStatic<MainCore, (anonymous namespace)::Q_QGS_mainCore::innerFunction, (anonymous namespace)::Q_QGS_mainCore::guard>::Type *	qglobalstatic.h	137
8 MainCore::instance	maincore.cpp	95
9 MainWindow::MainWindow	mainwindow.cpp	128
10 runQtApplication	main.cpp	196
11 main	main.cpp	248

When there is a configuration:

1 Preferences::resetToDefaults	preferences.cpp	48
2 Preferences::Preferences	preferences.cpp	25
3 MainSettings::MainSettings	mainsettings.cpp	30
4 MainCore::MainCore	maincore.cpp	76
5 Holder::Holder	maincore.cpp	92
6 (anonymous namespace)::Q_QGS_mainCore::innerFunction	maincore.cpp	92
7 QGlobalStatic<MainCore, (anonymous namespace)::Q_QGS_mainCore::innerFunction, (anonymous namespace)::Q_QGS_mainCore::guard>::operator QGlobalStatic<MainCore, (anonymous namespace)::Q_QGS_mainCore::innerFunction, (anonymous namespace)::Q_QGS_mainCore::guard>::Type *	qglobalstatic.h	137
8 MainCore::instance	maincore.cpp	95
9 MainWindow::MainWindow	mainwindow.cpp	128
10 runQtApplication	main.cpp	196
11 main	main.cpp	248
1 Preferences::resetToDefaults	preferences.cpp	48
2 MainSettings::resetToDefaults	mainsettings.cpp	235
3 MainSettings::MainSettings	mainsettings.cpp	32
4 MainCore::MainCore	maincore.cpp	76
5 Holder::Holder	maincore.cpp	92
6 (anonymous namespace)::Q_QGS_mainCore::innerFunction	maincore.cpp	92
7 QGlobalStatic<MainCore, (anonymous namespace)::Q_QGS_mainCore::innerFunction, (anonymous namespace)::Q_QGS_mainCore::guard>::operator QGlobalStatic<MainCore, (anonymous namespace)::Q_QGS_mainCore::innerFunction, (anonymous namespace)::Q_QGS_mainCore::guard>::Type *	qglobalstatic.h	137
8 MainCore::instance	maincore.cpp	95
9 MainWindow::MainWindow	mainwindow.cpp	128
10 runQtApplication	main.cpp	196
11 main	main.cpp	248

Station Position changed unexpectedly

It may happen that the position saved in the configuration for a station that didn't move (such as as desktop PC without a GPS receiver and whose public IP didn't change, with the "geoclue2" provider) when the "Auto-update from GPS" option is selected. This is unnecessary and wasteful but it is outside of the control of sdrangel so possible fixes are:

• deselect the auto-update option and type the desired position by hand
• install a GPS receiver

The label of the checkbox and the tooltip of the button could also be changed to refer to a generic GNSS and to suggest that position could be:

• the label could be changed from "Auto-update from GPS" to "Auto-update from GNSS"
• the tooltip could be changed from "Set position from GPS (if available)" to "Set position from GNSS (or other source if available)"

Order of presets changed after second run

The configuration that is automatically created the first time that sdrangel is run, contains presets for NOAA 18 and NOAA 19 (in this order), but after subsequent runs, the order is unnecessarily swapped in the .conf file.