hgext/narrow/narrowwirepeer.py

narrow: add narrow and ellipses as server capabilities

Right now we don't have a way to differentiate between whether a server can
serve ellipsis or not. The way we check whether a server is narrow enabled is by
checking bundle2 capability which does not scale outside of bundle2 world.

The goal is to use have wireprotocol commands just like remotefilelog for
widening the narrow clone, atleast in non-ellipses cases. Having a server
capability will help there as we can't rely on bundle2 capability there.

Also having a server capability is neat than having a bundle2 capability.

There are lot of things we can optimize locally on the client side by knowing
before hand that whether the server supports ellipses or not.

This will also help us in making sure that a client ellipses repo does not
communicate with a server repo without ellipses.

Differential Revision: https://phab.mercurial-scm.org/D4521

# 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.i18n import _
from mercurial import (
    error,
    extensions,
    hg,
    narrowspec,
    node,
    wireprotov1server,
)

from . import narrowbundle2

def uisetup():
    def peersetup(ui, peer):
        # We must set up the expansion before reposetup below, since it's used
        # at clone time before we have a repo.
        class expandingpeer(peer.__class__):
            def expandnarrow(self, narrow_include, narrow_exclude, nodes):
                ui.status(_("expanding narrowspec\n"))
                if not self.capable('exp-expandnarrow'):
                    raise error.Abort(
                        'peer does not support expanding narrowspecs')

                hex_nodes = (node.hex(n) for n in nodes)
                new_narrowspec = self._call(
                    'expandnarrow',
                    includepats=','.join(narrow_include),
                    excludepats=','.join(narrow_exclude),
                    nodes=','.join(hex_nodes))

                return narrowspec.parseserverpatterns(new_narrowspec)
        peer.__class__ = expandingpeer
    hg.wirepeersetupfuncs.append(peersetup)

    extensions.wrapfunction(wireprotov1server, '_capabilities', addnarrowcap)

def addnarrowcap(orig, repo, proto):
    """add the narrow capability to the server"""
    caps = orig(repo, proto)
    caps.append(narrowbundle2.NARROWCAP)
    if repo.ui.configbool('experimental', 'narrowservebrokenellipses'):
        caps.append(narrowbundle2.ELLIPSESCAP)
    return caps

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)