view tests/revlog-formatv0.py @ 38644:43d0619cec90

revlog: enforce chunk slicing down to a certain size

Limit maximum chunk size to 4x final size when reading a revision from a
revlog. We only apply this logic when the target size is known from the
revlog.

Ideally, revlog's delta chain would be written in a way that does not trigger
this extra slicing often. However, having this second guarantee that we won't
read unexpectedly large amounts of memory in all cases is important for the
future. Future delta chain building algorithms might have good reason to
create delta chain with such characteristics.

Including this code in core as soon as possible will make Mercurial 4.7
forward-compatible with such improvement.

#!/usr/bin/env python
# Copyright 2010 Intevation GmbH
# Author(s):
# Thomas Arendsen Hein <[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.

"""Create a Mercurial repository in revlog format 0

changeset:   0:a1ef0b125355
tag:         tip
user:        user
date:        Thu Jan 01 00:00:00 1970 +0000
files:       empty
description:
empty file
"""

from __future__ import absolute_import
import binascii
import os
import sys

files = [
    (b'formatv0/.hg/00changelog.i',
     b'000000000000004400000000000000000000000000000000000000'
     b'000000000000000000000000000000000000000000000000000000'
     b'0000a1ef0b125355d27765928be600cfe85784284ab3'),
    (b'formatv0/.hg/00changelog.d',
     b'756163613935613961356635353036303562366138343738336237'
     b'61623536363738616436356635380a757365720a3020300a656d70'
     b'74790a0a656d7074792066696c65'),
    (b'formatv0/.hg/00manifest.i',
     b'000000000000003000000000000000000000000000000000000000'
     b'000000000000000000000000000000000000000000000000000000'
     b'0000aca95a9a5f550605b6a84783b7ab56678ad65f58'),
    (b'formatv0/.hg/00manifest.d',
     b'75656d707479006238306465356431333837353835343163356630'
     b'35323635616431343461623966613836643164620a'),
    (b'formatv0/.hg/data/empty.i',
     b'000000000000000000000000000000000000000000000000000000'
     b'000000000000000000000000000000000000000000000000000000'
     b'0000b80de5d138758541c5f05265ad144ab9fa86d1db'),
    (b'formatv0/.hg/data/empty.d',
     b''),
]

def makedirs(name):
    """recursive directory creation"""
    parent = os.path.dirname(name)
    if parent:
        makedirs(parent)
    os.mkdir(name)

makedirs(os.path.join(*'formatv0/.hg/data'.split('/')))

for name, data in files:
    f = open(name, 'wb')
    f.write(binascii.unhexlify(data))
    f.close()

sys.exit(0)