hg

cmdutil: reimplement finddate() without using walkchangerevs()

It's simpler and slightly faster maybe because a fewer Python ops would
run.

Unscientific benchmark:

  $ python -m timeit \
    -s 'from mercurial import hg, ui, cmdutil; repo = hg.repository(ui.ui())' \
    'cmdutil.finddate(repo.ui, repo, "<2008-01-01")'
  (orig) 10 loops, best of 3: 1.45 sec per loop
  (new)  10 loops, best of 3: 1.25 sec per loop

Now "hg churn" and "hg grep" are the only users of walkchangerevs(), which
I want to refactor and fix bugs.

#!/usr/bin/env python
#
# mercurial - scalable distributed SCM
#
# Copyright 2005-2007 Matt 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.
from __future__ import absolute_import

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)

from hgdemandimport import tracing

with tracing.log('hg script'):
    # enable importing on demand to reduce startup time
    try:
        if sys.version_info[0] < 3 or sys.version_info >= (3, 6):
            import hgdemandimport

            hgdemandimport.enable()
    except ImportError:
        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

    dispatch.run()