view mercurial/node.py @ 32197:7bcc9a5ab96e

strip: make tree stripping O(changes) instead of O(repo)

The old tree stripping logic iterated over every tree revlog in the repo looking
for commits that had revs to be stripped. That's very inefficient in large
repos. Instead, let's look at what files are touched by the strip and only
inspect those revlogs.

I don't have actual perf numbers, since internally we don't use a true
treemanifest, but simply iterating over hundreds of thousands of revlogs takes
many, many seconds, so this should help tremendously when stripping only a few
commits.

# 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 = set((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

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