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alinebee / Boxer

The DOS game emulator that's fit for your Mac.
http://boxerapp.com/
769 stars 138 forks source link

Fix hang when regenerating gamebox icon #77

Closed alinebee closed 6 years ago

alinebee commented 6 years ago

This PR fixes a regression in the custom icon check that triggered a hang when launching any gamebox.

Explanation

As of https://github.com/alunbestor/Boxer/commit/4f0ed18f8a16597e44301a8d8b8fab485e032c36, NSWorkspace.URLHasCustomIcon started reporting NO for all files. This is because Apple's newer APIs for testing whether a file/folder has a custom icon are broken and have never worked; while their older Carbon-era APIs are deprecated as fuck.

Because of this regression, gameboxes would always claim they had no icon. Because of some poorly-thought-out KVO code, Boxer would then continually attempt to regenerate the icon: BXSession.representedIcon will attempt to generate a new icon and save it to BXSession.representedIcon.gamebox.coverArt. Meanwhile, BXSession.representedIcon.gamebox.coverArt was reported as a key path that affected BXSession.representedIcon, so setting it inadvertently triggered a new KVO notification saying that representedIcon had changed while it was in the process of being accessed, which caused an infinite recursion in another place that was observing representedIcon.

This is why I hate KVO.

Anyway, this PR tweaks the KVO to prevent the infinite loop, and also fixes the icon check by replacing the looks-like-it-ought-to-work-but-doesn't check with a less thorough approach that sniffs for the presence of a custom icon file. This should be good enough in 95% of cases and avoids leaving deprecated code around the place.

alinebee commented 6 years ago

cc @MaddTheSane: I'll periodically merge your changes into https://github.com/alunbestor/Boxer/tree/64bit/master, and will merge my own work into that branch via PR requests like this one, to provide more context to what is being changed. If you would like to me to CC you on those PRs (or even assign you as a reviewer) then I'd be happy to do so.