tests/test-encoding-align.t

nodemap: introduce an option to use mmap to read the nodemap mapping

The performance and memory benefit is much greater if we don't have to copy all
the data in memory for each information. So we introduce an option (on by
default) to read the data using mmap.

This changeset is the last one definition the API for index support nodemap
data. (they have to be able to use the mmaping).

Below are some benchmark comparing the best we currently have in 5.3 with the
final step of this series (using the persistent nodemap implementation in
Rust). The benchmark run `hg perfindex` with various revset and the following
variants:

Before:

 * do not use the persistent nodemap
 * use the CPython implementation of the index for nodemap
 * use mmapping of the changelog index

After:

 * use the MixedIndex Rust code, with the NodeTree object for nodemap access
   (still in review)
 * use the persistent nodemap data from disk
 * access the persistent nodemap data through mmap
 * use mmapping of the changelog index

The persistent nodemap greatly speed up  most operation on very large
repositories. Some of the previously very fast lookup end up a bit slower because
the persistent nodemap has to be setup. However the absolute slowdown is very
small and won't matters in the big picture.

Here are some numbers (in seconds) for the reference copy of mozilla-try:

Revset            Before   After     abs-change speedup

-10000:           0.004622 0.005532   0.000910  ×   0.83
-10:              0.000050 0.000132   0.000082  ×   0.37
tip               0.000052 0.000085   0.000033  ×   0.61
0 + (-10000:)     0.028222 0.005337  -0.022885  ×   5.29
0                 0.023521 0.000084  -0.023437  × 280.01
(-10000:) + 0     0.235539 0.005308  -0.230231  ×  44.37
(-10:) + :9       0.232883 0.000180  -0.232703  ×1293.79
(-10000:) + (:99) 0.238735 0.005358  -0.233377  ×  44.55
:99 + (-10000:)   0.317942 0.005593  -0.312349  ×  56.84
:9 + (-10:)       0.313372 0.000179  -0.313193  ×1750.68
:9                0.316450 0.000143  -0.316307  ×2212.93


On smaller repositories, the cost of nodemap related operation is not as big, so
the win is much more modest. Yet it helps shaving a handful of millisecond here
and there.

Here are some numbers (in seconds) for the reference copy of mercurial:

Revset            Before   After     abs-change speedup
-10:              0.000065 0.000097   0.000032  × 0.67
tip               0.000063 0.000078   0.000015  × 0.80
0                 0.000561 0.000079  -0.000482  × 7.10
-10000:           0.004609 0.003648  -0.000961  × 1.26
0 + (-10000:)     0.005023 0.003715  -0.001307  × 1.35
(-10:) + :9       0.002187 0.000108  -0.002079  ×20.25
(-10000:) + 0     0.006252 0.003716  -0.002536  × 1.68
(-10000:) + (:99) 0.006367 0.003707  -0.002660  × 1.71
:9 + (-10:)       0.003846 0.000110  -0.003736  ×34.96
:9                0.003854 0.000099  -0.003755  ×38.92
:99 + (-10000:)   0.007644 0.003778  -0.003866  × 2.02

Differential Revision: https://phab.mercurial-scm.org/D7894

Test alignment of multibyte characters

  $ HGENCODING=utf-8
  $ export HGENCODING
  $ hg init t
  $ cd t
  $ "$PYTHON" << EOF
  > from mercurial import pycompat
  > # (byte, width) = (6, 4)
  > s = b"\xe7\x9f\xad\xe5\x90\x8d"
  > # (byte, width) = (7, 7): odd width is good for alignment test
  > m = b"MIDDLE_"
  > # (byte, width) = (18, 12)
  > l = b"\xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d"
  > f = open('s', 'wb'); f.write(s); f.close()
  > f = open('m', 'wb'); f.write(m); f.close()
  > f = open('l', 'wb'); f.write(l); f.close()
  > # instant extension to show list of options
  > f = open('showoptlist.py', 'wb'); f.write(b"""# encoding: utf-8
  > from mercurial import registrar
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > 
  > @command(b'showoptlist',
  >     [(b's', b'opt1', b'', b'short width'  + (b' ' +%(s)s) * 8, %(s)s),
  >     (b'm', b'opt2', b'', b'middle width' + (b' ' + %(m)s) * 8, %(m)s),
  >     (b'l', b'opt3', b'', b'long width'   + (b' ' + %(l)s) * 8, %(l)s)],
  >     b'')
  > def showoptlist(ui, repo, *pats, **opts):
  >     '''dummy command to show option descriptions'''
  >     return 0
  > """ % {b's': pycompat.byterepr(s),
  >        b'm': pycompat.byterepr(m),
  >        b'l': pycompat.byterepr(l),
  >       })
  > f.close()
  > EOF
  $ S=`cat s`
  $ M=`cat m`
  $ L=`cat l`

alignment of option descriptions in help

  $ cat <<EOF > .hg/hgrc
  > [extensions]
  > ja_ext = `pwd`/showoptlist.py
  > EOF

check alignment of option descriptions in help

  $ hg help showoptlist
  hg showoptlist
  
  dummy command to show option descriptions
  
  options:
  
   -s --opt1 \xe7\x9f\xad\xe5\x90\x8d         short width \xe7\x9f\xad\xe5\x90\x8d \xe7\x9f\xad\xe5\x90\x8d \xe7\x9f\xad\xe5\x90\x8d \xe7\x9f\xad\xe5\x90\x8d \xe7\x9f\xad\xe5\x90\x8d \xe7\x9f\xad\xe5\x90\x8d \xe7\x9f\xad\xe5\x90\x8d \xe7\x9f\xad\xe5\x90\x8d (esc)
   -m --opt2 MIDDLE_      middle width MIDDLE_ MIDDLE_ MIDDLE_ MIDDLE_ MIDDLE_
                          MIDDLE_ MIDDLE_ MIDDLE_
   -l --opt3 \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d long width \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d (esc)
                          \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d (esc)
                          \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d (esc)
  
  (some details hidden, use --verbose to show complete help)


  $ rm -f s; touch s
  $ rm -f m; touch m
  $ rm -f l; touch l

add files

  $ cp s $S
  $ hg add $S
  $ cp m $M
  $ hg add $M
  $ cp l $L
  $ hg add $L

commit(1)

  $ echo 'first line(1)' >> s; cp s $S
  $ echo 'first line(2)' >> m; cp m $M
  $ echo 'first line(3)' >> l; cp l $L
  $ hg commit -m 'first commit' -u $S

commit(2)

  $ echo 'second line(1)' >> s; cp s $S
  $ echo 'second line(2)' >> m; cp m $M
  $ echo 'second line(3)' >> l; cp l $L
  $ hg commit -m 'second commit' -u $M

commit(3)

  $ echo 'third line(1)' >> s; cp s $S
  $ echo 'third line(2)' >> m; cp m $M
  $ echo 'third line(3)' >> l; cp l $L
  $ hg commit -m 'third commit' -u $L

check alignment of user names in annotate

  $ hg annotate -u $M
          \xe7\x9f\xad\xe5\x90\x8d: first line(2) (esc)
       MIDDLE_: second line(2)
  \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d: third line(2) (esc)

check alignment of filenames in diffstat

  $ hg diff -c tip --stat
   MIDDLE_      |  1 +
   \xe7\x9f\xad\xe5\x90\x8d         |  1 + (esc)
   \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d |  1 + (esc)
   3 files changed, 3 insertions(+), 0 deletions(-)

add branches/tags

  $ hg branch $S
  marked working directory as branch \xe7\x9f\xad\xe5\x90\x8d (esc)
  (branches are permanent and global, did you want a bookmark?)
  $ hg tag $S
  $ hg book -f $S
  $ hg branch $M
  marked working directory as branch MIDDLE_
  $ hg tag $M
  $ hg book -f $M
  $ hg branch $L
  marked working directory as branch \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d (esc)
  $ hg tag $L
  $ hg book -f $L

check alignment of branches

  $ hg branches
  \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d                   5:d745ff46155b (esc)
  MIDDLE_                        4:9259be597f19 (inactive)
  \xe7\x9f\xad\xe5\x90\x8d                           3:b06c5b6def9e (inactive) (esc)
  default                        2:64a70663cee8 (inactive)

check alignment of tags

  $ hg tags
  tip                                5:d745ff46155b
  \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d                       4:9259be597f19 (esc)
  MIDDLE_                            3:b06c5b6def9e
  \xe7\x9f\xad\xe5\x90\x8d                               2:64a70663cee8 (esc)

check alignment of bookmarks

  $ hg book
     MIDDLE_                   5:d745ff46155b
     \xe7\x9f\xad\xe5\x90\x8d                      4:9259be597f19 (esc)
   * \xe9\x95\xb7\xe3\x81\x84\xe9\x95\xb7\xe3\x81\x84\xe5\x90\x8d\xe5\x89\x8d              5:d745ff46155b (esc)