'Review Request: Protect animation list iterators against external changes'

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List:       kwin
Subject:    Review Request: Protect animation list iterators against external changes
From:       Thomas_Lübking <thomas.luebking () web ! de>
Date:       2013-01-03 23:15:46
Message-ID: 20130103231546.27291.93607 () vidsolbach ! de
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This is an automatically generated e-mail. To reply, visit:
http://git.reviewboard.kde.org/r/108151/
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Review request for kwin and Martin Gräßlin.

Description
-------

I recently started to run into random crashes on the heap and slightly \
started to fear to have broken sth. on activities... whatever.
Turned out* that moving BE::Faded to AnimationEffect and for the very first \
time actually using "animationEnded" to chain animations (fade out -> fade \
in) would (actually obviously) alter the m_animations list what \
unfortunately turns our nice little iterators into random junk.

So this patch tracks list manipulations (in this case during the iteration \
calling animationEnded, being the natural candidate) and when they happen, \
re-validates the iterators (the map traversion is required due to the \
internals of QMap/QHash; the list could instead also be accessed by \
entry->first.at(animationCounter) instead; not sure about performance \
impact but it would have made the patch much larger ;-)

* I actually figured it because resizing on fullscreen changes always \
worked like crap because the window gets to resizes in a row (once for the \
decoration being removed and then the actual resize to the FS geometry) \
what got me multiplicative traslation/scaling. Chaining this made the \
crashes pretty reproducible but the result is pretty cool =)

Diffs
-----

  kwin/libkwineffects/kwinanimationeffect.cpp e0a6694 

Diff: http://git.reviewboard.kde.org/r/108151/diff/

Testing
-------

hehe - i un/fullscreened mplayer about a hundred times the last few \
minutes. That crashed nearly *each* time before the patch.

Thanks,

Thomas Lübking

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      This is an automatically generated e-mail. To reply, visit:
      <a href="http://git.reviewboard.kde.org/r/108151/">http://git.reviewboard.kde.org/r/108151/</a>
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<div>Review request for kwin and Martin Gräßlin.</div>
<div>By Thomas Lübking.</div>

<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description \
</h1>  <table width="100%" bgcolor="#ffffff" cellspacing="0" \
cellpadding="10" style="border: 1px solid #b8b5a0">  <tr>
  <td>
   <pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: \
-moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: \
break-word;">I recently started to run into random crashes on the heap and \
slightly started to fear to have broken sth. on activities... whatever.
Turned out* that moving BE::Faded to AnimationEffect and for the very first \
time actually using &quot;animationEnded&quot; to chain animations (fade \
out -&gt; fade in) would (actually obviously) alter the m_animations list \
what unfortunately turns our nice little iterators into random junk.

So this patch tracks list manipulations (in this case during the iteration \
calling animationEnded, being the natural candidate) and when they happen, \
re-validates the iterators (the map traversion is required due to the \
internals of QMap/QHash; the list could instead also be accessed by \
entry-&gt;first.at(animationCounter) instead; not sure about performance \
impact but it would have made the patch much larger ;-)

* I actually figured it because resizing on fullscreen changes always \
worked like crap because the window gets to resizes in a row (once for the \
decoration being removed and then the actual resize to the FS geometry) \
what got me multiplicative traslation/scaling. Chaining this made the \
crashes pretty reproducible but the result is pretty cool =)</pre>  </td>
 </tr>
</table>

<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing \
</h1> <table width="100%" bgcolor="#ffffff" cellspacing="0" \
cellpadding="10" style="border: 1px solid #b8b5a0">  <tr>
  <td>
   <pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: \
-moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: \
break-word;">hehe - i un/fullscreened mplayer about a hundred times the \
last few minutes. That crashed nearly *each* time before the patch.</pre>
  </td>
 </tr>
</table>

<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> \
</h1> <ul style="margin-left: 3em; padding-left: 0;">

 <li>kwin/libkwineffects/kwinanimationeffect.cpp <span style="color: \
grey">(e0a6694)</span></li>

</ul>

<p><a href="http://git.reviewboard.kde.org/r/108151/diff/" \
style="margin-left: 3em;">View Diff</a></p>

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