view mercurial/node.py @ 36146:29dd37a418aa

bdiff: write a native version of splitnewlines

./hg perfunidiff mercurial/manifest.py 0 --count 500 --profile before:
! wall 0.309280 comb 0.350000 user 0.290000 sys 0.060000 (best of 32)

./hg perfunidiff mercurial/manifest.py 0 --count 500 --profile after:
! wall 0.241572 comb 0.260000 user 0.240000 sys 0.020000 (best of 39)

so it's about 20% faster. I hate Python. I wish we could usefully
write this in Rust, but it doesn't look like that's realistic without
using the cpython crate, which I'd still like to avoid.

Differential Revision: https://phab.mercurial-scm.org/D1973

# 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 = b"\0" * 20
nullhex = hex(nullid)

# Phony node value to stand-in for new files in some uses of
# manifests.
newnodeid = '!' * 20
addednodeid = ('0' * 15) + 'added'
modifiednodeid = ('0' * 12) + 'modified'

wdirnodes = {newnodeid, addednodeid, modifiednodeid}

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

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