view mercurial/node.py @ 26644:74de1c59f71c

clonebundles: filter on bundle specification Not all clients are capable of reading every bundle. Currently, content negotiation to ensure a server sends a client a compatible bundle format is performed at request time. The response bundle is dynamically generated at request time, so this works fine. Clone bundles are statically generated *before* the request. This means that a modern server could produce bundles that a legacy client isn't capable of reading. Without some kind of "type hint" in the clone bundles manifest, a client may attempt to download an incompatible bundle. Furthermore, a client may not realize a bundle is incompatible until it has processed part of the bundle (imagine consuming a 1 GB changegroup bundle2 part only to discover the bundle2 part afterwards is incompatibl). This would waste time and resources. And it isn't very user friendly. Clone bundle manifests thus need to advertise the *exact* format of the hosted bundles so clients may filter out entries that they don't know how to read. This patch introduces that mechanism. We introduce the BUNDLESPEC attribute to declare the "bundle specification" of the entry. Bundle specifications are parsed using exchange.parsebundlespecification, which uses the same strings as the "--type" argument to `hg bundle`. The supported bundle specifications are well defined and backwards compatible. When a client encounters a BUNDLESPEC that is invalid or unsupported, it silently ignores the entry.
author Gregory Szorc <gregory.szorc@gmail.com>
date Tue, 13 Oct 2015 11:45:30 -0700
parents 738314da6c75
children 18f50b8cbf1e
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# node.py - basic nodeid manipulation for mercurial
#
# Copyright 2005, 2006 Matt Mackall <mpm@selenic.com>
#
# 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

nullrev = -1
nullid = "\0" * 20

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

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

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