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This is an automatically generated e-mail. To reply, visit:
<a href="https://git.reviewboard.kde.org/r/128944/">https://git.reviewboard.kde.org/r/128944/</a>
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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;">Thanks for looking into this!</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">When I wrote the code I thought it would be mostly transitional so I didn't pay much attention to efficiency.</p></pre>
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<a href="https://git.reviewboard.kde.org/r/128944/diff/1/?file=477140#file477140line215" style="color: black; font-weight: bold; text-decoration: underline;">src/lib/plugin/desktopfileparser.cpp</a>
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(Diff revision 1)
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<td colspan="4"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">QVector<CustomPropertyDefinition>* parseServiceTypesFile(QString path)</pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">QByteArray</span> <span class="n">line</span> <span class="o">=</span> <span class="n">df</span><span class="p">.</span><span class="n">readLine</span><span class="p">().</span><span class="n">trimmed</span><span class="p">();</span></pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">QByteArray</span> <span class="n">line</span> <span class="o">=</span> <span class="n">df</span><span class="p">.</span><span class="n">readLine</span><span class="p">().</span><span class="n">trimmed</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;">I guess the same optimization could be applied here.</p></pre>
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<a href="https://git.reviewboard.kde.org/r/128944/diff/1/?file=477140#file477140line477" style="color: black; font-weight: bold; text-decoration: underline;">src/lib/plugin/desktopfileparser.cpp</a>
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(Diff revision 1)
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="k">while</span> <span class="p">(</span><span class="n">stream</span><span class="p">.</span><span class="n">readLineInto</span><span class="p">(</span><span class="o">&</span><span class="n">line</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;">Using readLineInto() is really useful to reduce unnecessary allocations. However the function is quite new: <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">This function was introduced in Qt 5.5</code></p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">Do we depend on Qt 5.5 already?</p></pre>
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<a href="https://git.reviewboard.kde.org/r/128944/diff/1/?file=477140#file477140line478" style="color: black; font-weight: bold; text-decoration: underline;">src/lib/plugin/desktopfileparser.cpp</a>
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(Diff revision 1)
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">lineNr</span><span class="o">++</span><span class="p">;</span></pre></td>
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<td bgcolor="#ffffff" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">lineNr</span><span class="o">++</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;">If I read this correctly we no longer handle leading/trailing spaces properly. Does the test still pass? Or maybe I forgot to add tests for this case.
trimmed() will add another allocation, maybe we can change the string in place?</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">There is <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">QStringRef::trimmed()</code> so <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">line.midRef(0).trimmed()</code> should work without any extra allocations, right?</p></pre>
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<a href="https://git.reviewboard.kde.org/r/128944/diff/1/?file=477140#file477140line506" style="color: black; font-weight: bold; text-decoration: underline;">src/lib/plugin/desktopfileparser.cpp</a>
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(Diff revision 1)
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="k">const</span> <span class="n">Q<span class="hl">ByteArray</span></span> <span class="n">valueEscaped</span> <span class="o">=</span> <span class="n">escapeValue</span><span class="p">(</span><span class="n">valueRaw</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">const</span> <span class="n">Q<span class="hl">String</span></span> <span class="n">valueEscaped</span> <span class="o">=</span> <span class="n">escapeValue</span><span class="p">(</span><span class="n">valueRaw</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;">We can remove valueEscaped now that both are of type QString</p></pre>
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<p>- Alex Richardson</p>
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<p>On September 19th, 2016, 4:20 p.m. BST, Aleix Pol Gonzalez wrote:</p>
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<div>Review request for KDE Frameworks.</div>
<div>By Aleix Pol Gonzalez.</div>
<p style="color: grey;"><i>Updated Sept. 19, 2016, 4:20 p.m.</i></p>
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<b style="color: #575012; font-size: 10pt;">Repository: </b>
kcoreaddons
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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;">While analising plasmashell under heaptrack, one of the sore spots is temporary allocations within DesktopFileParser. This improves the situation by:</p>
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<li style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: normal;">Only converting to QString/utf8 once.</li>
<li style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: normal;">Using QStringRef instead of fully splitting QString to parse them.</li>
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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;">tests still pass, plasma still works normally.</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">heaptrack plasmashell:</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">after:
allocations: 4169312
leaked allocations: 83225
temporary allocations: 606902</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">before:
allocations: 4680691
leaked allocations: 84825
temporary allocations: 819292</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>src/lib/plugin/desktopfileparser.cpp <span style="color: grey">(2eb198d)</span></li>
<li>src/lib/plugin/desktopfileparser_p.h <span style="color: grey">(c61b297)</span></li>
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<p><a href="https://git.reviewboard.kde.org/r/128944/diff/" style="margin-left: 3em;">View Diff</a></p>
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