view mercurial/node.py @ 22309:a65697c3f20e

obsolete: avoid slow, generic date parsing

Simple profiling of `hg log -r .` revealed ~18,000 calls to
mercurial.i18n.gettext() on the author's repository. The
culprit was 3 _() calls in util.parsedate() multiplied by
~6000 obsmarkers originating from the parsing of obsmarkers.

Changing the obsmarker code to parse the stored format of
dates instead of going through a generic path eliminates these
gettext() lookups and makes `hg log -r .` execute ~10% faster
on the author's repo. The performance gain is proportional to
the number of obsmarkers.

The author attempted to patch util.parsedate() to avoid the
gettext() lookups. However, that code is whacky and the author
is jet lagged, so the approach was not attempted.

# node.py - basic nodeid manipulation for mercurial
#
# Copyright 2005, 2006 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.

import binascii

nullrev = -1
nullid = "\0" * 20

# This ugly style has a noticeable effect in manifest parsing
hex = binascii.hexlify
bin = binascii.unhexlify

def short(node):
    return hex(node[:6])