[PATCH 4 of 4 V2] rust-cpython: using rustext.dagop.headrevs in revlog

[Georges Racinet]

# HG changeset patch
# User Georges Racinet <georges.racinet at octobus.net>
# Date 1547651966 -3600
#      Wed Jan 16 16:19:26 2019 +0100
# Node ID 3cab9658d270ce28cb589f6adbf0a19dffe51341
# Parent  eae29e210636ee44851e0caa385097a090c60af8
# EXP-Topic revset.predicates
rust-cpython: using rustext.dagop.headrevs in revlog

As with the previous oxidation series, revlog plays the role
of the factory, either using its parents function, or passing the
index.

In most of the cases about heads revsetbenchmarks, this seems to be
either neutral or an improvement. There aren't many cases where it's
actually slower and they don't look too bad.

Result by revset
================

Revision:
 0) parent of this changeset: rust-cpython: binding for headrevs()
 1) this changeset: rust-cpython: using rustext.dagop.headrevs in revlog

revset #0: heads(commonancestors(last(head(), 2)))
   plain         min           max           first         last          reverse       rev..rst      rev..ast      sort          sor..rst      sor..ast
0) 0.002913      0.002845      0.002976      0.002953      0.002978      0.002894      0.002946      0.003127      0.002949      0.002977      0.003074
1) 0.002830      0.002900      0.002942      0.003066      0.002994      0.002881      0.003041      0.002973      0.002942      0.003008      0.003012

revset #1: heads(commonancestors(head()))
   plain         min           max           first         last          reverse       rev..rst      rev..ast      sort          sor..rst      sor..ast
0) 0.124867      0.117328      0.117523      0.117500      0.114464      0.128686      0.121959      0.119129      0.114949      0.124387      0.119485
1) 0.125079      0.124376 106% 0.114437      0.118340      0.124021 108% 0.123225      0.126748      0.122144      0.126391 109% 0.116410  93% 0.121342

revset #2: heads(all())
   plain         min           max           first         last          reverse       rev..rst      rev..ast      sort          sor..rst      sor..ast
0) 0.080521      0.079977      0.079199      0.079454      0.084119      0.079578      0.083369      0.080215      0.080788      0.079157      0.080142
1) 0.033069  41% 0.032773  40% 0.033060  41% 0.032708  41% 0.032987  39% 0.032458  40% 0.033019  39% 0.032306  40% 0.032341  40% 0.033317  42% 0.032645  40%

revset #3: heads(-10000:-1)
   plain         min           max           first         last          reverse       rev..rst      rev..ast      sort          sor..rst      sor..ast
0) 0.008496      0.008642      0.008398      0.008665      0.008896      0.008857      0.008864      0.009749      0.009690      0.009445      0.008902
1) 0.002694  31% 0.002678  30% 0.002692  32% 0.002766  31% 0.002753  30% 0.002931  33% 0.003023  34% 0.002787  28% 0.002735  28% 0.002789  29% 0.002943  33%

revset #4: (-5000:-1000) and heads(-10000:-1)
   plain         min           max           first         last          reverse       rev..rst      rev..ast      sort          sor..rst      sor..ast
0) 0.008835      0.008711      0.008920      0.008824      0.008948      0.009422      0.009073      0.008751      0.009244      0.009264      0.009489
1) 0.003033  34% 0.003027  34% 0.002885  32% 0.002911  32% 0.002850  31% 0.003068  32% 0.002971  32% 0.002890  33% 0.003239  35% 0.002973  32% 0.003068  32%

revset #5: heads(matching(tip, "author"))
   plain         min           max           first         last          reverse       rev..rst      rev..ast      sort          sor..rst      sor..ast
0) 15.82091      15.47578      15.95506      15.74816      15.72207      15.72779      15.52043      15.65250      15.40250      15.46190      15.34036
1) 15.29257      15.39349      15.52757      15.41417      15.58991      15.42382      15.46773      15.48543      15.43644      15.76070      15.32104

revset #6: heads(matching(tip, "author")) and -10000:-1
   plain         min           max           first         last          reverse       rev..rst      rev..ast      sort          sor..rst      sor..ast
0) 15.74241      15.63808      15.46853      15.77480      15.61004      15.80385      15.44905      15.38059      15.34111      15.45029      15.85194
1) 15.51474      15.45938      15.28755      15.77045      15.38245      15.40625      15.53653      15.31534      15.64134      15.43437      15.29366

revset #7: (-10000:-1) and heads(matching(tip, "author"))
   plain         min           max           first         last          reverse       rev..rst      rev..ast      sort          sor..rst      sor..ast
0) 15.37988      15.59717      16.07863      15.29263      15.46472      15.84978      15.35538      15.50673      15.37396      15.42426      15.44425
1) 15.51504      15.38657      15.30847      15.39458      15.60453      15.26237      15.45240      15.34210      15.36410      15.53354      15.67735

diff -r eae29e210636 -r 3cab9658d270 mercurial/revlog.py
--- a/mercurial/revlog.py	Fri Jan 18 13:38:01 2019 +0100
+++ b/mercurial/revlog.py	Wed Jan 16 16:19:26 2019 +0100
@@ -1121,6 +1121,8 @@
                 return self.index.headrevs()
             except AttributeError:
                 return self._headrevs()
+        if rustext is not None:
+            return rustext.dagop.headrevs(self.index, revs)
         return dagop.headrevs(revs, self._uncheckedparentrevs)
 
     def computephases(self, roots):