hg

fastannotate: initial import from Facebook's hg-experimental

I made as few changes as I could to get the tests to pass, but this
was a bit involved due to some churn in the blame code since someone
last gave fastannotate any TLC.

There's still follow-up work here to rip out support for old versions
of hg and to integrate the protocol with modern standards.

Some performance numbers (all on my 2016 MacBook Pro with a 2.6Ghz i7):

Mercurial mercurial/manifest.py
traditional blame
time: real 1.050 secs (user 0.990+0.000 sys 0.060+0.000)
build cache
time: real 5.900 secs (user 5.720+0.000 sys 0.110+0.000)
fastannotate
time: real 0.120 secs (user 0.100+0.000 sys 0.020+0.000)

Mercurial mercurial/localrepo.py
traditional blame
time: real 3.330 secs (user 3.220+0.000 sys 0.070+0.000)
build cache
time: real 30.610 secs (user 30.190+0.000 sys 0.230+0.000)
fastannotate
time: real 0.180 secs (user 0.160+0.000 sys 0.020+0.000)

mozilla-central dom/ipc/ContentParent.cpp
traditional blame
time: real 7.640 secs (user 7.210+0.000 sys 0.380+0.000)
build cache
time: real 98.650 secs (user 97.000+0.000 sys 0.950+0.000)
fastannotate
time: real 1.580 secs (user 1.340+0.000 sys 0.240+0.000)

mozilla-central dom/base/nsDocument.cpp
traditional blame
time: real 17.110 secs (user 16.490+0.000 sys 0.500+0.000)
build cache
time: real 399.750 secs (user 394.520+0.000 sys 2.610+0.000)
fastannotate
time: real 1.780 secs (user 1.530+0.000 sys 0.240+0.000)

So building the cache is expensive (but might be faster with xdiff
enabled), but the blame results are *way* faster.

Differential Revision: https://phab.mercurial-scm.org/D3994

#!/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

if os.environ.get('HGUNICODEPEDANTRY', False):
    try:
        reload(sys)
        sys.setdefaultencoding("undefined")
    except NameError:
        pass

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:
    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()