view hgext/narrow/narrowwirepeer.py @ 38717:aa21a9ad46ea

sparse-revlog: new requirement enabled with format.sparse-revlog

The meaning of the new 'sparse-revlog' requirement is that the revlogs are
allowed to contain wider delta chains with larger holes between the interesting
chunks. These sparse delta chains should be read in several chunks to avoid a
potential explosion of memory usage.

Former version won't know how to read a delta chain in several chunks. They
would keep reading them in a single read, and therefore would be subject to the
potential memory explosion. Hence this new requirement: only versions having
support of sparse-revlog reading should be allowed to read such a revlog.

Implementation of this new algorithm and tools to enable or disable the
requirement will follow in the next changesets.

# 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,
)

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)

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)