hgext/narrow/narrowwirepeer.py

wireprotov2: support exposing linknode of file revisions

When supporting shallow file storage, clients may fetch file revisions
by changeset. But they may not readily know which changeset introduced a
specific file revision. The "linknode" is used to record which changeset
introduces which file revision.

This commit teaches the "filedata" and "filesdata" wire protocol commands
to expose the linknode for file revisions. The implementation is likely
wrong when hidden changesets are in play, since the linknode may refer to
a hidden changeset. We can deal with this problem later.

Differential Revision: https://phab.mercurial-scm.org/D5167

# narrowwirepeer.py - passes narrow spec with unbundle command
#
# Copyright 2017 Google, Inc.
#
# 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 mercurial import (
    bundle2,
    error,
    extensions,
    hg,
    narrowspec,
    pycompat,
    wireprototypes,
    wireprotov1peer,
    wireprotov1server,
)

def uisetup():
    wireprotov1peer.wirepeer.narrow_widen = peernarrowwiden

def reposetup(repo):
    def wirereposetup(ui, peer):
        def wrapped(orig, cmd, *args, **kwargs):
            if cmd == 'unbundle':
                # TODO: don't blindly add include/exclude wireproto
                # arguments to unbundle.
                include, exclude = repo.narrowpats
                kwargs[r"includepats"] = ','.join(include)
                kwargs[r"excludepats"] = ','.join(exclude)
            return orig(cmd, *args, **kwargs)
        extensions.wrapfunction(peer, '_calltwowaystream', wrapped)
    hg.wirepeersetupfuncs.append(wirereposetup)

@wireprotov1server.wireprotocommand('narrow_widen', 'oldincludes oldexcludes'
                                                    ' newincludes newexcludes'
                                                    ' commonheads cgversion'
                                                    ' known ellipses',
                                    permission='pull')
def narrow_widen(repo, proto, oldincludes, oldexcludes, newincludes,
                 newexcludes, commonheads, cgversion, known, ellipses):
    """wireprotocol command to send data when a narrow clone is widen. We will
    be sending a changegroup here.

    The current set of arguments which are required:
    oldincludes: the old includes of the narrow copy
    oldexcludes: the old excludes of the narrow copy
    newincludes: the new includes of the narrow copy
    newexcludes: the new excludes of the narrow copy
    commonheads: list of heads which are common between the server and client
    cgversion(maybe): the changegroup version to produce
    known: list of nodes which are known on the client (used in ellipses cases)
    ellipses: whether to send ellipses data or not
    """

    preferuncompressed = False
    try:
        oldincludes = wireprototypes.decodelist(oldincludes)
        newincludes = wireprototypes.decodelist(newincludes)
        oldexcludes = wireprototypes.decodelist(oldexcludes)
        newexcludes = wireprototypes.decodelist(newexcludes)
        # validate the patterns
        narrowspec.validatepatterns(set(oldincludes))
        narrowspec.validatepatterns(set(newincludes))
        narrowspec.validatepatterns(set(oldexcludes))
        narrowspec.validatepatterns(set(newexcludes))

        common = wireprototypes.decodelist(commonheads)
        known = None
        if known:
            known = wireprototypes.decodelist(known)
        if ellipses == '0':
            ellipses = False
        else:
            ellipses = bool(ellipses)
        cgversion = cgversion
        newmatch = narrowspec.match(repo.root, include=newincludes,
                                    exclude=newexcludes)
        oldmatch = narrowspec.match(repo.root, include=oldincludes,
                                    exclude=oldexcludes)

        bundler = bundle2.widen_bundle(repo, oldmatch, newmatch, common, known,
                                             cgversion, ellipses)
    except error.Abort as exc:
        bundler = bundle2.bundle20(repo.ui)
        manargs = [('message', pycompat.bytestr(exc))]
        advargs = []
        if exc.hint is not None:
            advargs.append(('hint', exc.hint))
        bundler.addpart(bundle2.bundlepart('error:abort', manargs, advargs))
        preferuncompressed = True

    chunks = bundler.getchunks()
    return wireprototypes.streamres(gen=chunks,
                                    prefer_uncompressed=preferuncompressed)

def peernarrowwiden(remote, **kwargs):
    for ch in (r'oldincludes', r'newincludes', r'oldexcludes', r'newexcludes',
               r'commonheads', r'known'):
        kwargs[ch] = wireprototypes.encodelist(kwargs[ch])

    kwargs[r'ellipses'] = '%i' % bool(kwargs[r'ellipses'])
    f = remote._callcompressable('narrow_widen', **kwargs)
    return bundle2.getunbundler(remote.ui, f)