contrib/simplemerge

upgraderepo: add a config option for parallel computation

The option is put to use to compute new copy tracing side data in parallel. It
use the multiprocessing module as it had the appropriate primitive for what we
needed. Gregory Szorc had concerned on windows so we disabled it there.

See inline comment for details on the parallel implementation.

#!/usr/bin/env python
from __future__ import absolute_import

import getopt
import sys

import hgdemandimport

hgdemandimport.enable()

from mercurial.i18n import _
from mercurial import (
    context,
    error,
    fancyopts,
    pycompat,
    simplemerge,
    ui as uimod,
)
from mercurial.utils import procutil, stringutil

options = [
    (b'L', b'label', [], _(b'labels to use on conflict markers')),
    (b'a', b'text', None, _(b'treat all files as text')),
    (b'p', b'print', None, _(b'print results instead of overwriting LOCAL')),
    (b'', b'no-minimal', None, _(b'no effect (DEPRECATED)')),
    (b'h', b'help', None, _(b'display help and exit')),
    (b'q', b'quiet', None, _(b'suppress output')),
]

usage = _(
    b'''simplemerge [OPTS] LOCAL BASE OTHER

    Simple three-way file merge utility with a minimal feature set.

    Apply to LOCAL the changes necessary to go from BASE to OTHER.

    By default, LOCAL is overwritten with the results of this operation.
'''
)


class ParseError(Exception):
    """Exception raised on errors in parsing the command line."""


def showhelp():
    pycompat.stdout.write(usage)
    pycompat.stdout.write(b'\noptions:\n')

    out_opts = []
    for shortopt, longopt, default, desc in options:
        out_opts.append(
            (
                b'%2s%s'
                % (
                    shortopt and b'-%s' % shortopt,
                    longopt and b' --%s' % longopt,
                ),
                b'%s' % desc,
            )
        )
    opts_len = max([len(opt[0]) for opt in out_opts])
    for first, second in out_opts:
        pycompat.stdout.write(b' %-*s  %s\n' % (opts_len, first, second))


try:
    for fp in (sys.stdin, pycompat.stdout, sys.stderr):
        procutil.setbinary(fp)

    opts = {}
    try:
        bargv = [a.encode('utf8') for a in sys.argv[1:]]
        args = fancyopts.fancyopts(bargv, options, opts)
    except getopt.GetoptError as e:
        raise ParseError(e)
    if opts[b'help']:
        showhelp()
        sys.exit(0)
    if len(args) != 3:
        raise ParseError(_(b'wrong number of arguments').decode('utf8'))
    local, base, other = args
    sys.exit(
        simplemerge.simplemerge(
            uimod.ui.load(),
            context.arbitraryfilectx(local),
            context.arbitraryfilectx(base),
            context.arbitraryfilectx(other),
            **pycompat.strkwargs(opts)
        )
    )
except ParseError as e:
    e = stringutil.forcebytestr(e)
    pycompat.stdout.write(b"%s: %s\n" % (sys.argv[0].encode('utf8'), e))
    showhelp()
    sys.exit(1)
except error.Abort as e:
    pycompat.stderr.write(b"abort: %s\n" % e)
    sys.exit(255)
except KeyboardInterrupt:
    sys.exit(255)