view mercurial/pushkey.py @ 39814:d059cb669632

wireprotov2: allow multiple fields to follow revision maps The *data wire protocol commands emit a series of CBOR values. Because revision/delta data may be large, their data is emitted outside the map as a top-level bytestring value. Before this commit, we'd emit a single optional bytestring value after the revision descriptor map. This got the job done. But it was limiting in that we could only send a single field. And, it required the consumer to know that the presence of a key in the map implied the existence of a following bytestring value. This commit changes the encoding strategy so top-level bytestring values in the stream are explicitly denoted in a "fieldsfollowing" key. This key contains an array defining what fields that follow and the expected size of each field. By defining things this way, we can easily send N bytestring values without any ambiguity about their order. In addition, clients only need to know how to parse ``fieldsfollowing`` to know if extra values are present. Because this breaks backwards compatibility, we've bumped the version number of the wire protocol version 2 API endpoint. Differential Revision: https://phab.mercurial-scm.org/D4620
author Gregory Szorc <gregory.szorc@gmail.com>
date Thu, 20 Sep 2018 12:57:23 -0700
parents 7b200566e474
children 57875cf423c9
line wrap: on
line source

# pushkey.py - dispatching for pushing and pulling keys
#
# Copyright 2010 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

from . import (
    bookmarks,
    encoding,
    obsolete,
    phases,
)

def _nslist(repo):
    n = {}
    for k in _namespaces:
        n[k] = ""
    if not obsolete.isenabled(repo, obsolete.exchangeopt):
        n.pop('obsolete')
    return n

_namespaces = {"namespaces": (lambda *x: False, _nslist),
               "bookmarks": (bookmarks.pushbookmark, bookmarks.listbookmarks),
               "phases": (phases.pushphase, phases.listphases),
               "obsolete": (obsolete.pushmarker, obsolete.listmarkers),
              }

def register(namespace, pushkey, listkeys):
    _namespaces[namespace] = (pushkey, listkeys)

def _get(namespace):
    return _namespaces.get(namespace, (lambda *x: False, lambda *x: {}))

def push(repo, namespace, key, old, new):
    '''should succeed iff value was old'''
    pk = _get(namespace)[0]
    return pk(repo, key, old, new)

def list(repo, namespace):
    '''return a dict'''
    lk = _get(namespace)[1]
    return lk(repo)

encode = encoding.fromlocal

decode = encoding.tolocal

def encodekeys(keys):
    """encode the content of a pushkey namespace for exchange over the wire"""
    return '\n'.join(['%s\t%s' % (encode(k), encode(v)) for k, v in keys])

def decodekeys(data):
    """decode the content of a pushkey namespace from exchange over the wire"""
    result = {}
    for l in data.splitlines():
        k, v = l.split('\t')
        result[decode(k)] = decode(v)
    return result