... Should have no effect on generated code, except perhaps some slight faster
virtual function calls. Mostly useful as documentation of design intent.
Tried to mark every one of our classes that inherits from another, or is a
base for others, or has abstract virtual functions, and a few others besides.
... Solution was to stack-allocate!
To make the leak happen, export with "external program" and edit the command to
"foobar" or other nonextistent program instead of lame.
This relies on three new nyquist scripts to actually do the editing. The peak-snapping code in FrequencyWindow has been extracted into a new class, SpectrumAnalyst, to provide peak-snapping in spectrogram too.
Was able to make the bug occur after lots of fast clicking around, by double-clicking Preview in Amplify dialog.
The key seems to be the call to wxYield. That function is obsolete, but looking at the documentation for its successor, wxApp::Yield():
"Caution should be exercised, however, since yielding may allow the user to perform actions which are not compatible with the current task. Disabling menu items or whole menus during processing can avoid unwanted reentrance of code: see ::wxSafeYield for a better function."
That sounds like exactly the situations where this has occurred. And the documentation for ::wxSafeYieldsays:
"This function is similar to wxYield, except that it disables the user input to all program windows before calling wxYield and re-enables it again afterwards."
Sounds like what we need. So I went through the code and for all the wxYield and wxGetApp()::Yield occurrences where Audacity is doing some drawing or already in the process of responding to a GUI event, I replaced them with ::wxSafeYield. Replaced all the remaining wxYield calls with calls to wxGetApp()::Yield().
Haven't been able to replicate the bug since these changes. Please test.
