contrib/hgperf

rebase: add boolean config item rebase.store-source

This allows to use rebase without recording a rebase_source extra
field. This is useful for example to build a mirror converted from
another SCM (such as svn) by converting only new revisions, and
then incrementally add them to the destination by pulling from the
newly converted (unrelated) repo and rebasing the new revisions
onto the last old already stored changeset. Without this patch the
rebased changesets would always receive some rebase_source that
would depend on the particular history of the conversion process,
instead of only depending on the original source revisions.

This is used to implement a hg mirror repo of SvarDOS (a partially
nonfree but completely redistributable DOS distribution) in the
scripts at https://hg.pushbx.org/ecm/svardos.scr/

In particular, cre.sh creates an svn mirror, upd.sh recreates an
entire hg repo from the svn mirror (which takes too long to do in a
regular job), and akt.sh uses hg convert with the config item
convert.svn.startrev to incrementally convert only the two most
recent revisions already found in the mirror destination plus any
possible new revisions. If any are found, the temporary repo's
changesets are pulled into the destination (as changesets from an
unrelated repository). Then the changesets corresponding to the new
revisions are rebased onto the prior final changeset. (Finally, the
two remaining duplicates of the prior head and its parent are
stripped from the destination repository.)

Without this patch, the particular rebase_source extra field would
depend on the order and times at which akt.sh was used, instead of
only depending on the source repository. In other words, whatever
sequence of upd.sh and akt.sh is used at whatever times, it is
desired that the final output repositories always match each other
exactly.

#!/usr/bin/env python3
#
# hgperf - measure performance of Mercurial commands
#
# Copyright 2014 Olivia Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''measure performance of Mercurial commands

Using ``hgperf`` instead of ``hg`` measures performance of the target
Mercurial command. For example, the execution below measures
performance of :hg:`heads --topo`::

    $ hgperf heads --topo

All command output via ``ui`` is suppressed, and just measurement
result is displayed: see also "perf" extension in "contrib".

Costs of processing before dispatching to the command function like
below are not measured::

    - parsing command line (e.g. option validity check)
    - reading configuration files in

But ``pre-`` and ``post-`` hook invocation for the target command is
measured, even though these are invoked before or after dispatching to
the command function, because these may be required to repeat
execution of the target command correctly.
'''

import os
import sys

libdir = '@LIBDIR@'

if libdir != '@' 'LIBDIR' '@':
    if not os.path.isabs(libdir):
        libdir = os.path.join(
            os.path.dirname(os.path.realpath(__file__)), libdir
        )
        libdir = os.path.abspath(libdir)
    sys.path.insert(0, libdir)

# enable importing on demand to reduce startup time
try:
    from mercurial import demandimport

    demandimport.enable()
except ImportError:
    import sys

    sys.stderr.write(
        "abort: couldn't find mercurial libraries in [%s]\n"
        % ' '.join(sys.path)
    )
    sys.stderr.write("(check your install and PYTHONPATH)\n")
    sys.exit(-1)

from mercurial import (
    dispatch,
    util,
)


def timer(func, title=None):
    results = []
    begin = util.timer()
    count = 0
    while True:
        ostart = os.times()
        cstart = util.timer()
        r = func()
        cstop = util.timer()
        ostop = os.times()
        count += 1
        a, b = ostart, ostop
        results.append((cstop - cstart, b[0] - a[0], b[1] - a[1]))
        if cstop - begin > 3 and count >= 100:
            break
        if cstop - begin > 10 and count >= 3:
            break
    if title:
        sys.stderr.write("! %s\n" % title)
    if r:
        sys.stderr.write("! result: %s\n" % r)
    m = min(results)
    sys.stderr.write(
        "! wall %f comb %f user %f sys %f (best of %d)\n"
        % (m[0], m[1] + m[2], m[1], m[2], count)
    )


orgruncommand = dispatch.runcommand


def runcommand(lui, repo, cmd, fullargs, ui, options, d, cmdpats, cmdoptions):
    ui.pushbuffer()
    lui.pushbuffer()
    timer(
        lambda: orgruncommand(
            lui, repo, cmd, fullargs, ui, options, d, cmdpats, cmdoptions
        )
    )
    ui.popbuffer()
    lui.popbuffer()


dispatch.runcommand = runcommand

dispatch.run()