tests/test-log-exthook.t

bundle2: inline changegroup.readexactly()

Profiling reveals this loop is pretty tight. Literally any
function call elimination can make a big difference.

This commit inlines the relatively trivial changegroup.readexactly()
method inside the loop.

The results with `hg perfbundleread` on a bundle of the Firefox repo
speak for themselves:

! read(8k)
! wall 0.679730 comb 0.680000 user 0.140000 sys 0.540000 (best of 15)
! read(16k)
! wall 0.577228 comb 0.570000 user 0.080000 sys 0.490000 (best of 17)
! read(32k)
! wall 0.516060 comb 0.520000 user 0.040000 sys 0.480000 (best of 20)
! read(128k)
! wall 0.496378 comb 0.490000 user 0.010000 sys 0.480000 (best of 20)
! bundle2 iterparts()
! wall 3.460903 comb 3.460000 user 2.760000 sys 0.700000 (best of 3)
! wall 3.056811 comb 3.050000 user 2.340000 sys 0.710000 (best of 4)
! bundle2 iterparts() seekable
! wall 4.312722 comb 4.310000 user 3.480000 sys 0.830000 (best of 3)
! wall 4.007676 comb 4.000000 user 3.170000 sys 0.830000 (best of 3)
! bundle2 part seek()
! wall 6.754764 comb 6.740000 user 3.970000 sys 2.770000 (best of 3)
! wall 6.267110 comb 6.250000 user 3.480000 sys 2.770000 (best of 3)
! bundle2 part read(8k)
! wall 3.668004 comb 3.660000 user 2.960000 sys 0.700000 (best of 3)
! wall 3.404164 comb 3.400000 user 2.650000 sys 0.750000 (best of 3)
! bundle2 part read(16k)
! wall 3.489196 comb 3.480000 user 2.750000 sys 0.730000 (best of 3)
! wall 3.197972 comb 3.200000 user 2.490000 sys 0.710000 (best of 4)
! bundle2 part read(32k)
! wall 3.388569 comb 3.380000 user 2.640000 sys 0.740000 (best of 3)
! wall 3.060557 comb 3.060000 user 2.340000 sys 0.720000 (best of 4)
! bundle2 part read(128k)
! wall 3.276415 comb 3.270000 user 2.560000 sys 0.710000 (best of 4)
! wall 2.952209 comb 2.950000 user 2.230000 sys 0.720000 (best of 4)

Differential Revision: https://phab.mercurial-scm.org/D1392

Test hg log changeset printer external hook
-------------------------------------------

  $ cat > $TESTTMP/logexthook.py <<EOF
  > from __future__ import absolute_import
  > from mercurial import (
  >   cmdutil,
  >   commands,
  >   repair,
  > )
  > def rot13description(self, ctx):
  >     summary = "summary".encode('rot13')
  >     description = ctx.description().strip().splitlines()[0].encode('rot13')
  >     self.ui.write("%s:     %s\n" % (summary, description))
  > def reposetup(ui, repo):
  >     cmdutil.changeset_printer._exthook = rot13description
  > EOF

Prepare the repository

  $ hg init empty
  $ cd empty
  $ touch ROOT
  $ hg commit -A -m "Root" ROOT

  $ touch a b c
  $ hg commit -A -m "Add A, B, C" a b c

Check the log

  $ hg log --config extensions.t=$TESTTMP/logexthook.py
  changeset:   1:70fc82b23320
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  fhzznel:     Nqq N, O, P
  summary:     Add A, B, C
  
  changeset:   0:b00443a54871
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  fhzznel:     Ebbg
  summary:     Root
  
Check that exthook is working with graph log too

  $ hg log -G --config extensions.t=$TESTTMP/logexthook.py
  @  changeset:   1:70fc82b23320
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  fhzznel:     Nqq N, O, P
  |  summary:     Add A, B, C
  |
  o  changeset:   0:b00443a54871
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     fhzznel:     Ebbg
     summary:     Root