revset: translate node directly with changelog in 'head'
Using 'repo[X]' is much slower because it creates a 'changectx' object and goes
though multiple layers of code to do so. It is also error prone if there is
tags, bookmarks, branch or other names that could map to a node hash and take
precedence (user are wicked).
This provides a significant performance boost on repository with a lot of
heads. Benchmark result for a repo with 1181 heads.
revset: head()
plain min last reverse
0) 0.014853 0.014371 0.014350 0.015161
1) 0.001402 9% 0.000975 6% 0.000874 6% 0.001415 9%
revset: head() - public()
plain min last reverse
0) 0.015121 0.014420 0.014560 0.015028
1) 0.001674 11% 0.001109 7% 0.000980 6% 0.001693 11%
revset: draft() and head()
plain min last reverse
0) 0.015976 0.014490 0.014214 0.015892
1) 0.002335 14% 0.001018 7% 0.000887 6% 0.002340 14%
The speed up is visible even when other more costly revset are in use
revset: head() and author("mpm")
plain min last reverse
0) 0.105419 0.090046 0.017169 0.108180
1) 0.090721 86% 0.077602 86% 0.003556 20% 0.093324 86%
<tr>
<td class="diffstat-file"><a href="#l{fileno}.1">{file|escape}</a></td>
<td class="diffstat-total" align="right">{total}</td>
<td class="diffstat-graph">
<span class="diffstat-add" style="width:{addpct}%;"> </span>
<span class="diffstat-remove" style="width:{removepct}%;"> </span>
</td>
</tr>