EmulationActivity has an instance of Settings. If you go to
SettingsActivity from EmulationActivity and change some settings,
the changes get saved to disk, but EmulationActivity's Settings
instance still contains the old settings in its map of all
settings (assuming the EmulationActivity was not killed by the
system to save memory). Then, once you're done playing your
game and exit EmulationActivity, EmulationActivity calls
Settings.saveSettings. This call to saveSettings first overwrites
the entire INI file with its map of all settings (which is
outdated) in order to save any legacy settings that have changed
(which they haven't, since the GUI doesn't let you change legacy
settings while a game is running). Then, it asks the new config
system to write the most up-to-date values available for non-legacy
settings, which should make all the settings be up-to-date again.
The problem here is that the new config system would skip writing
to disk if no settings changes had been made since the last time
we asked it to write to disk (i.e. since SettingsActivity exited).
NB: Calling Settings.loadSettings in EmulationActivity.onResume
is not a working solution. I assume this is because
SettingsActivity saves its settings in onStop and not onPause.
This is already handled by SurfaceDestroyed. In the worst case,
the extra code could even race with SurfaceDestroyed if they
are triggered at the same time, but this is highly improbable.
Time for yet another new iteration of working around the
"surface destruction during boot" problem...
This time, the strategy is to use a mutex in MainAndroid.cpp.
We generally have no reason to call these functions on our own, so
there's not much reason to declare them, especially not in the cpp
file where they're defined. In case we ever do get a reason to do
it, we can add declarations for just the functions that need them.
During emulation, when LocalGame has a value but CurrentRun
doesn't, we want to read from LocalGame, not CurrentRun. This
change exposes a LAYER_ACTIVE option that handles this correctly.
The main activity loads settings essentially as soon as it
starts, in order to determine which tab to show. If the process
of stopping emulation has not finished at this point, a race
condition may be triggered where two IOS kernels are created
at once due to the emulation thread loading or saving the
SYSCONF while the GUI thread is loading the SYSCONF. To fix
this, we can wait for emulation to fully end before returning.
Because this race condition is hard to reproduce, I have not
been able to test that this actually fixes the race condition,
or even that the cause of the race condition is exactly what I
believe it is. But I am relatively confident.
Léo Lam