mercurial/node.py

branchmap: check node against changelog instead of repo

Testing 'node in repo' requires constructing a changectx, which is a little
expensive.  Testing 'repo.changelog.hasnode(node)' is notably faster. This
saves 10-20ms off of every command, when testing a few thousand nodes from the
branch cache.

I considered changing the implementation of localrepository.__contains__ so
every place would benefit from the change, but since
localrepository.__contains__ uses changectx to check if the commit exists, it
means it supports a wider range of possible inputs (like revs, hashes, '.',
etc), so it seemed unnecessarily risky.

# 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])