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This is an automatically generated e-mail. To reply, visit:
<a href="https://git.reviewboard.kde.org/r/121134/">https://git.reviewboard.kde.org/r/121134/</a>
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<p>Ship it!</p>
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<a href="https://git.reviewboard.kde.org/r/121134/diff/6/?file=328847#file328847line317" style="color: black; font-weight: bold; text-decoration: underline;">kdecore/kernel/kglobal.cpp</a>
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(Diff revision 6)
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<td colspan="4"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">QString KGlobal::caption()</pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="cm"> * The counter should of course be used in atomic fashion if the reference counting mechanism</span></pre></td>
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<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">this comment isn't useful, it's obvious that the use of an atomic int is for thread safety.</p></pre>
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<a href="https://git.reviewboard.kde.org/r/121134/diff/6/?file=328847#file328847line320" style="color: black; font-weight: bold; text-decoration: underline;">kdecore/kernel/kglobal.cpp</a>
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(Diff revision 6)
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<td colspan="2"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">static int s_refCount = 0;</pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="k">static</span> <span class="kt">int</span> <span class="n">s_refCount</span> <span class="o">=</span> <span class="mi">0</span><span class="p">;</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="k">static</span> <span class="n">QBasicAtomicInt</span> <span class="n">s_allowQuit</span> <span class="o">=</span> <span class="n">Q_BASIC_ATOMIC_INITIALIZER</span><span class="p">(</span><span class="mi">0</span><span class="p">);</span></pre></td>
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<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">use false instead of 0, and add a "// bool" comment, for the reader to know this is a bool, conceptually, not an int.</p></pre>
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<a href="https://git.reviewboard.kde.org/r/121134/diff/6/?file=328847#file328847line331" style="color: black; font-weight: bold; text-decoration: underline;">kdecore/kernel/kglobal.cpp</a>
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(Diff revision 6)
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<td colspan="2"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">static int s_refCount = 0;</pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="o">--</span><span class="n">s_refCount</span><span class="p">;</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="kt">int</span> <span class="n">prevRefCount</span> <span class="o">=</span> <span class="n">s_refCount</span><span class="p">.</span><span class="n">fetchAndAddOrdered</span><span class="p">(</span><span class="o">-</span><span class="mi">1</span><span class="p">);</span></pre></td>
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<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">const int prevRefCount = ...</p></pre>
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<a href="https://git.reviewboard.kde.org/r/121134/diff/6/?file=328847#file328847line332" style="color: black; font-weight: bold; text-decoration: underline;">kdecore/kernel/kglobal.cpp</a>
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(Diff revision 6)
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<td colspan="2"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">static int s_refCount = 0;</pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="c1">//kDebug() << "KGlobal::deref() : refCount = " << s_refCount;</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="k">if</span> <span class="p">(</span><span class="n">prevRefCount</span> <span class="o"><=</span> <span class="mi">1</span> <span class="o">&&</span> <span class="kt">int</span><span class="p">(</span><span class="n">s_allowQuit</span><span class="p">))</span> <span class="p">{</span></pre></td>
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<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">Would s_allowQuit.load() compile? I forgot the Qt4 API since it changed in Qt5.</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">It would be slightly better imho, for readability.</p></pre>
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<p>- David Faure</p>
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<p>On November 16th, 2014, 8:22 p.m. UTC, René J.V. Bertin wrote:</p>
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<div>Review request for KDE Software on Mac OS X, kdelibs and David Faure.</div>
<div>By René J.V. Bertin.</div>
<p style="color: grey;"><i>Updated Nov. 16, 2014, 8:22 p.m.</i></p>
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<b style="color: #575012; font-size: 10pt;">Repository: </b>
kdelibs
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
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<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;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">I have been experiencing unexpected exits from KDevelop that were not due to any kind of error in the KDevelop code; it was as if someone told the application to exit normally. This happens mostly on OS X, but also sometimes on Linux.
I finally traced this to <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">KGlobal::deref</code> reaching a zero reference count and invoking <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">QCoreApplication::quit</code> when called from one of KDevelop's KJob dtors. There does not appear to be a reference counting mismatch in the code, so the issue might be due to a race condition in KGlobal::ref/deref.</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">This patch introduces thread-safety to KGlobal's reference counting by turning the simple global <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">static int s_refCount</code> into a <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">static QAtomicInt s_refCount</code>. I consider this an important bug fix regardless of whether it corrects the issue I have with KDevelop.</p></pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
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<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;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">On OS X 10.6.8 only for now.</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">NB: Qt itself uses the QAtomicInt's parent class (QBasicAtomicInt) for its own reference counter used for implicit sharing. This is thus well-tested code that is unlikely to introduce regressions to a core KDE feature.</p></pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
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<li>kdecore/kernel/kglobal.cpp <span style="color: grey">(cf003a4)</span></li>
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<p><a href="https://git.reviewboard.kde.org/r/121134/diff/" style="margin-left: 3em;">View Diff</a></p>
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