Prevent race on applications quitting whilst save jobs are in process

[davidedmundson]

If an application calls quit or closes all windows we still want to finish saving the password. Qt provides a mechanism to defer the exit whilst jobs are active.

This brings us in line with KDE's KJob.

Note this change can cause a niche behavioural change with QCoreApplication applications that incorrectly have with quit loop enabled and use the main event loop so should probably not be backported.

[frankosterfeld]

Wouldn't this break when using Qtkeychain jobs outside the main thread?

[davidedmundson]

Good question.

It would hold a lock on the application. holding a lock on the app (QCoreApplicationPrivate::ref) is thread safe. It won't break.

But it doesn't protect the thread case, one could still kill a thread with an active job, though I would say that's the caller's responsibility?