<table><tr><td style="">davidedmundson added a comment.
</td><a style="text-decoration: none; padding: 4px 8px; margin: 0 8px 8px; float: right; color: #464C5C; font-weight: bold; border-radius: 3px; background-color: #F7F7F9; background-image: linear-gradient(to bottom,#fff,#f1f0f1); display: inline-block; border: 1px solid rgba(71,87,120,.2);" href="https://phabricator.kde.org/D22946">View Revision</a></tr></table><br /><div><div><p>I think I didn't explain myself properly. There's a way to do a version that has no race conditions.</p>

<p>Order of events needs to be</p>

<ol class="remarkup-list">
<li class="remarkup-list-item">We try to register our service name with the queued flag</li>
<li class="remarkup-list-item">We see if we succeeded to register it immediately</li>
<li class="remarkup-list-item">If it fails, we send a non-blocking quit method to whoever currently owns that name</li>
<li class="remarkup-list-item">and then wait for our application to be given the service name we've already requested</li>
</ol>

<p>all except 3 exist already.</p></div></div><br /><div><strong>INLINE COMMENTS</strong><div><div style="margin: 6px 0 12px 0;"><div style="border: 1px solid #C7CCD9; border-radius: 3px;"><div style="padding: 0; background: #F7F7F7; border-color: #e3e4e8; border-style: solid; border-width: 0 0 1px 0; margin: 0;"><div style="color: #74777d; background: #eff2f4; padding: 6px 8px; overflow: hidden;"><a style="float: right; text-decoration: none;" href="https://phabricator.kde.org/D22946#inline-141701">View Inline</a><span style="color: #4b4d51; font-weight: bold;">kdbusservice.cpp:171</span></div>
<div style="font: 11px/15px "Menlo", "Consolas", "Monaco", monospace; white-space: pre-wrap; clear: both; padding: 4px 0; margin: 0;"><div style="padding: 0 8px; margin: 0 4px; background: rgba(251, 175, 175, .7);">        <span style="color: #aa4000">if</span> <span class="p">(</span><span class="n">options</span> <span style="color: #aa2211">&</span> <span class="n">KDBusService</span><span style="color: #aa2211">::<span class="bright"></span></span><span class="bright"></span><span class="n"><span class="bright">Unique</span></span><span class="p">)</span> <span class="p">{</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">        <span style="color: #aa4000">if</span> <span class="p">(</span><span class="n">options</span> <span style="color: #aa2211">&</span> <span class="n">KDBusService</span><span style="color: #aa2211">::<span class="bright"></span></span><span class="bright"></span><span class="n"><span class="bright">Replace</span></span><span class="bright"> </span><span style="color: #aa2211"><span class="bright">&&</span></span><span class="bright"> </span><span class="n"><span class="bright">QDBusConnection</span></span><span class="bright"></span><span style="color: #aa2211"><span class="bright">::</span></span><span class="bright"></span><span class="n"><span class="bright">sessionBus</span></span><span class="bright"></span><span class="p"><span class="bright">().</span></span><span class="bright"></span><span class="n"><span class="bright">interface</span></span><span class="bright"></span><span class="p"><span class="bright">()</span></span><span class="bright"></span><span style="color: #aa2211"><span class="bright">-></span></span><span class="bright"></span><span class="n"><span class="bright">isServiceRegistered</span></span><span class="bright"></span><span class="p"><span class="bright">(</span></span><span class="bright"></span><span class="n"><span class="bright">d</span></span><span class="bright"></span><span style="color: #aa2211"><span class="bright">-></span></span><span class="bright"></span><span class="n"><span class="bright">serviceName</span></span><span class="bright"></span><span class="p"><span class="bright">)</span>)</span> <span class="p">{</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">            <span style="color: #aa4000">auto</span> <span class="n">message</span> <span style="color: #aa2211">=</span> <span class="n">QDBusMessage</span><span style="color: #aa2211">::</span><span class="n">createMethodCall</span><span class="p">(</span><span class="n">d</span><span style="color: #aa2211">-></span><span class="n">serviceName</span><span class="p">,</span>
</div></div></div>
<div style="margin: 8px 0; padding: 0 12px;"><p style="padding: 0; margin: 8px;">This is still racey</p></div></div><br /><div style="border: 1px solid #C7CCD9; border-radius: 3px;"><div style="padding: 0; background: #F7F7F7; border-color: #e3e4e8; border-style: solid; border-width: 0 0 1px 0; margin: 0;"><div style="color: #74777d; background: #eff2f4; padding: 6px 8px; overflow: hidden;"><a style="float: right; text-decoration: none;" href="https://phabricator.kde.org/D22946#inline-141702">View Inline</a><span style="color: #4b4d51; font-weight: bold;">kdbusservice.cpp:181</span></div>
<div style="font: 11px/15px "Menlo", "Consolas", "Monaco", monospace; white-space: pre-wrap; clear: both; padding: 4px 0; margin: 0;"><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">                <span class="n">QEventLoop</span> <span class="n">unregistrationLoop</span><span class="p">;</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">                <span class="n">connect</span><span class="p">(</span><span class="n">bus</span><span class="p">,</span> <span style="color: #aa2211">&</span><span class="n">QDBusConnectionInterface</span><span style="color: #aa2211">::</span><span class="n">serviceUnregistered</span><span class="p">,</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">                        <span style="color: #aa4000">this</span><span class="p">,</span> <span class="p">[</span><span style="color: #aa2211">&</span><span class="n">unregistrationLoop</span><span class="p">,</span> <span style="color: #aa4000">this</span><span class="p">](</span><span style="color: #aa4000">const</span> <span class="n">QString</span> <span style="color: #aa2211">&</span><span class="n">service</span><span class="p">)</span> <span class="p">{</span>
</div></div></div>
<div style="margin: 8px 0; padding: 0 12px;"><p style="padding: 0; margin: 8px;">QDBusConnectionInterface::serviceUnregistered is very different to QDBusServiceWatcher::serviceUnregistered</p>

<p style="padding: 0; margin: 8px;">QDBusConnectionInterface::serviceUnregistered will be called when our process loses the service name it had.</p>

<p style="padding: 0; margin: 8px;">Our process hasn't even requested a service name yet, so this won't happen.</p></div></div></div></div></div><br /><div><strong>REPOSITORY</strong><div><div>R271 KDBusAddons</div></div></div><br /><div><strong>REVISION DETAIL</strong><div><a href="https://phabricator.kde.org/D22946">https://phabricator.kde.org/D22946</a></div></div><br /><div><strong>To: </strong>apol, Frameworks, davidedmundson<br /><strong>Cc: </strong>davidedmundson, broulik, kossebau, kde-frameworks-devel, LeGast00n, GB_2, michaelh, ngraham, bruns<br /></div>