view mercurial/node.py @ 28306:1778770e1982

changelog: lazy decode description (API)

Currently, changelog reading decodes read values. This is wasteful
because a lot of times consumers aren't interested in some of these
values.

This patch changes description decoding to occur in changectx as
needed.

revsets reading changelog entries appear to speed up slightly:

revset #7: author(lmoscovicz)
   plain
0) 0.906329
1) 0.872653

revset #8: author(mpm)
   plain
0) 0.903478
1) 0.878037

revset #9: author(lmoscovicz) or author(mpm)
   plain
0) 1.817855
1) 1.778680

revset #10: author(mpm) or author(lmoscovicz)
   plain
0) 1.837052
1) 1.764568

# 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.

from __future__ import absolute_import

import binascii

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

nullrev = -1
nullid = "\0" * 20
nullhex = hex(nullid)

# pseudo identifiers for working directory
# (they are experimental, so don't add too many dependencies on them)
wdirrev = 0x7fffffff
wdirid = "\xff" * 20

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