<table><tr><td style="">romangg 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/D23918">View Revision</a></tr></table><br /><div><div><blockquote style="border-left: 3px solid #8C98B8;
color: #6B748C;
font-style: italic;
margin: 4px 0 12px 0;
padding: 8px 12px;
background-color: #F8F9FC;">
<div style="font-style: normal;
padding-bottom: 4px;">In <a href="https://phabricator.kde.org/D23918#530689" style="background-color: #e7e7e7;
border-color: #e7e7e7;
border-radius: 3px;
padding: 0 4px;
font-weight: bold;
color: black;text-decoration: none;">D23918#530689</a>, <a href="https://phabricator.kde.org/p/zzag/" style="
border-color: #f1f7ff;
color: #19558d;
background-color: #f1f7ff;
border: 1px solid transparent;
border-radius: 3px;
font-weight: bold;
padding: 0 4px;">@zzag</a> wrote:</div>
<div style="margin: 0;
padding: 0;
border: 0;
color: rgb(107, 116, 140);"><p>I haven't received any strong arguments why we need a subclass of QVector<AbstractOutput *>. Outputs overloads constructor to implement some sort of covariance. However, that doesn't qualify as a good argument because the right solution would be to add a helper function that could perform these conversions.</p>
<p>In many cases, inheriting from a vector type is a no-no. You should do that only if there's no any other way around.</p></div>
</blockquote>
<p>You need to provide sources for such generic statements. If you would be a computer science professor of 30 years I would believe them without asking for such but we are not.</p>
<blockquote style="border-left: 3px solid #a7b5bf; color: #464c5c; font-style: italic; margin: 4px 0 12px 0; padding: 4px 12px; background-color: #f8f9fc;"><hr class="remarkup-hr" />
<blockquote style="border-left: 3px solid #a7b5bf; color: #464c5c; font-style: italic; margin: 4px 0 12px 0; padding: 4px 12px; background-color: #f8f9fc;"><p>This change makes everything too explicit. Boo!</p></blockquote>
<p>I personally don't consider it to be a problem. That's C++ after all.</p>
<p>Templates are invariant and making conversions between Collection<Base> and Collection<Derived> explicit is a good thing because this way we have less magic in the code.</p></blockquote>
<p>Independent of researched facts I agree though with Vlad that the qvector_cast feels better since it's more explicit and David's QVector subclassing, while being an interesting solution, feels kind of forbidden magic in comparison.</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/D23918#inline-135287">View Inline</a><span style="color: #4b4d51; font-weight: bold;">utils.h:240</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">QVector</span><span style="color: #aa2211"><</span><span class="n">To</span><span style="color: #aa2211">></span> <span class="n">mapped</span><span class="p">;</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);"> <span class="n">mapped</span><span class="p">.</span><span class="n">reserve</span><span class="p">(</span><span class="n">collection</span><span class="p">.</span><span class="n">size</span><span class="p">());</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);"> <span class="n">std</span><span style="color: #aa2211">::</span><span class="n">copy</span><span class="p">(</span><span class="n">collection</span><span class="p">.</span><span class="n">constBegin</span><span class="p">(),</span> <span class="n">collection</span><span class="p">.</span><span class="n">constEnd</span><span class="p">(),</span> <span class="n">std</span><span style="color: #aa2211">::</span><span class="n">back_inserter</span><span class="p">(</span><span class="n">mapped</span><span class="p">));</span>
</div></div></div>
<div style="margin: 8px 0; padding: 0 12px;"><p style="padding: 0; margin: 8px;">For simple data types according to Qt docs resize is faster. It's a micro-optimization, but since the outputs are queried often maybe it's worth it. I assume we could use template specialization for <tt style="background: #ebebeb; font-size: 13px;">AbstractOutput*</tt> as <tt style="background: #ebebeb; font-size: 13px;">To</tt> type, or just use no template at all? Although having a templated qvector_cast is nice.</p></div></div></div></div></div><br /><div><strong>REPOSITORY</strong><div><div>R108 KWin</div></div></div><br /><div><strong>REVISION DETAIL</strong><div><a href="https://phabricator.kde.org/D23918">https://phabricator.kde.org/D23918</a></div></div><br /><div><strong>To: </strong>zzag, KWin<br /><strong>Cc: </strong>romangg, davidedmundson, alexeymin, kwin, LeGast00n, The-Feren-OS-Dev, sbergeron, jraleigh, fbampaloukas, GB_2, mkulinski, ragreen, jackyalcine, Pitel, iodelay, crozbo, bwowk, ZrenBot, ngraham, himcesjf, lesliezhai, ali-mohamed, hardening, jensreuterberg, abetts, sebas, apol, mart<br /></div>