# narrowbundle2.py - bundle2 extensions for narrow repository support

#

# 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.

import errno

import struct

from mercurial.i18n import _

from mercurial import (

    bundle2,

    changegroup,

    error,

    exchange,

    localrepo,

    narrowspec,

    repair,

    requirements,

    scmutil,

    util,

    wireprototypes,

)

from mercurial.utils import stringutil

_NARROWACL_SECTION = b'narrowacl'

_CHANGESPECPART = b'narrow:changespec'

_RESSPECS = b'narrow:responsespec'

_SPECPART = b'narrow:spec'

_SPECPART_INCLUDE = b'include'

_SPECPART_EXCLUDE = b'exclude'

_KILLNODESIGNAL = b'KILL'

_DONESIGNAL = b'DONE'

_ELIDEDCSHEADER = b'>20s20s20sl'  # cset id, p1, p2, len(text)

_ELIDEDMFHEADER = b'>20s20s20s20sl'  # manifest id, p1, p2, link id, len(text)

_CSHEADERSIZE = struct.calcsize(_ELIDEDCSHEADER)

_MFHEADERSIZE = struct.calcsize(_ELIDEDMFHEADER)

# Serve a changegroup for a client with a narrow clone.

def getbundlechangegrouppart_narrow(

    bundler,

    repo,

    source,

    bundlecaps=None,

    b2caps=None,

    heads=None,

    common=None,

    **kwargs

):

    assert repo.ui.configbool(b'experimental', b'narrowservebrokenellipses')

    cgversions = b2caps.get(b'changegroup')

    cgversions = [

        v

        for v in cgversions

        if v in changegroup.supportedoutgoingversions(repo)

    ]

    if not cgversions:

        raise ValueError(_(b'no common changegroup version'))

    version = max(cgversions)

    include = sorted(filter(bool, kwargs.get('includepats', [])))

    exclude = sorted(filter(bool, kwargs.get('excludepats', [])))

    generateellipsesbundle2(

        bundler,

        repo,

        include,

        exclude,

        version,

        common,

        heads,

        kwargs.get('depth', None),

    )

def generateellipsesbundle2(

    bundler,

    repo,

    include,

    exclude,

    version,

    common,

    heads,

    depth,

):

    match = narrowspec.match(repo.root, include=include, exclude=exclude)

    if depth is not None:

        depth = int(depth)

        if depth < 1:

            raise error.Abort(_(b'depth must be positive, got %d') % depth)

    heads = set(heads or repo.heads())

    common = set(common or [repo.nullid])

    visitnodes, relevant_nodes, ellipsisroots = exchange._computeellipsis(

        repo, common, heads, set(), match, depth=depth

    )

    repo.ui.debug(b'Found %d relevant revs\n' % len(relevant_nodes))

    if visitnodes:

        packer = changegroup.getbundler(

            version,

            repo,

            matcher=match,

            ellipses=True,

            shallow=depth is not None,

            ellipsisroots=ellipsisroots,

            fullnodes=relevant_nodes,

        )

        cgdata = packer.generate(common, visitnodes, False, b'narrow_widen')

        part = bundler.newpart(b'changegroup', data=cgdata)

        part.addparam(b'version', version)

        if scmutil.istreemanifest(repo):

            part.addparam(b'treemanifest', b'1')

def generate_ellipses_bundle2_for_widening(

    bundler,

    repo,

    oldmatch,

    newmatch,

    version,

    common,

    known,

):

    common = set(common or [repo.nullid])

    # Steps:

    # 1. Send kill for "$known & ::common"

    #

    # 2. Send changegroup for ::common

    #

    # 3. Proceed.

    #

    # In the future, we can send kills for only the specific

    # nodes we know should go away or change shape, and then

    # send a data stream that tells the client something like this:

    #

    # a) apply this changegroup

    # b) apply nodes XXX, YYY, ZZZ that you already have

    # c) goto a

    #

    # until they've built up the full new state.

    knownrevs = {repo.changelog.rev(n) for n in known}

    # TODO: we could send only roots() of this set, and the

    # list of nodes in common, and the client could work out

    # what to strip, instead of us explicitly sending every

    # single node.

    deadrevs = knownrevs

    def genkills():

        for r in deadrevs:

            yield _KILLNODESIGNAL

            yield repo.changelog.node(r)

        yield _DONESIGNAL

    bundler.newpart(_CHANGESPECPART, data=genkills())

    newvisit, newfull, newellipsis = exchange._computeellipsis(

        repo, set(), common, knownrevs, newmatch

    )

    if newvisit:

        packer = changegroup.getbundler(

            version,

            repo,

            matcher=newmatch,

            ellipses=True,

            shallow=False,

            ellipsisroots=newellipsis,

            fullnodes=newfull,

        )

        cgdata = packer.generate(common, newvisit, False, b'narrow_widen')

        part = bundler.newpart(b'changegroup', data=cgdata)

        part.addparam(b'version', version)

        if scmutil.istreemanifest(repo):

            part.addparam(b'treemanifest', b'1')

@bundle2.parthandler(_SPECPART, (_SPECPART_INCLUDE, _SPECPART_EXCLUDE))

def _handlechangespec_2(op, inpart):

    # XXX: This bundle2 handling is buggy and should be removed after hg5.2 is

    # released. New servers will send a mandatory bundle2 part named

    # 'Narrowspec' and will send specs as data instead of params.

    # Refer to issue5952 and 6019

    includepats = set(inpart.params.get(_SPECPART_INCLUDE, b'').splitlines())

    excludepats = set(inpart.params.get(_SPECPART_EXCLUDE, b'').splitlines())

    narrowspec.validatepatterns(includepats)

    narrowspec.validatepatterns(excludepats)

    if not requirements.NARROW_REQUIREMENT in op.repo.requirements:

        op.repo.requirements.add(requirements.NARROW_REQUIREMENT)

        scmutil.writereporequirements(op.repo)

    op.repo.setnarrowpats(includepats, excludepats)

    narrowspec.copytoworkingcopy(op.repo)

@bundle2.parthandler(_RESSPECS)

def _handlenarrowspecs(op, inpart):

    data = inpart.read()

    inc, exc = data.split(b'\0')

    includepats = set(inc.splitlines())

    excludepats = set(exc.splitlines())

    narrowspec.validatepatterns(includepats)

    narrowspec.validatepatterns(excludepats)

    if requirements.NARROW_REQUIREMENT not in op.repo.requirements:

        op.repo.requirements.add(requirements.NARROW_REQUIREMENT)

        scmutil.writereporequirements(op.repo)

    op.repo.setnarrowpats(includepats, excludepats)

    narrowspec.copytoworkingcopy(op.repo)

@bundle2.parthandler(_CHANGESPECPART)

def _handlechangespec(op, inpart):

    repo = op.repo

    cl = repo.changelog

    # changesets which need to be stripped entirely. either they're no longer

    # needed in the new narrow spec, or the server is sending a replacement

    # in the changegroup part.

    clkills = set()

    # A changespec part contains all the updates to ellipsis nodes

    # that will happen as a result of widening or narrowing a

    # repo. All the changes that this block encounters are ellipsis

    # nodes or flags to kill an existing ellipsis.

    chunksignal = changegroup.readexactly(inpart, 4)

    while chunksignal != _DONESIGNAL:

        if chunksignal == _KILLNODESIGNAL:

            # a node used to be an ellipsis but isn't anymore

            ck = changegroup.readexactly(inpart, 20)

            if cl.hasnode(ck):

                clkills.add(ck)

        else:

            raise error.Abort(

                _(b'unexpected changespec node chunk type: %s') % chunksignal

            )

        chunksignal = changegroup.readexactly(inpart, 4)

    if clkills:

        # preserve bookmarks that repair.strip() would otherwise strip

        op._bookmarksbackup = repo._bookmarks

        class dummybmstore(dict):

            def applychanges(self, repo, tr, changes):

                pass

        localrepo.localrepository._bookmarks.set(repo, dummybmstore())

        chgrpfile = repair.strip(

            op.ui, repo, list(clkills), backup=True, topic=b'widen'

        )

        if chgrpfile:

            op._widen_uninterr = repo.ui.uninterruptible()

            op._widen_uninterr.__enter__()

            # presence of _widen_bundle attribute activates widen handler later

            op._widen_bundle = chgrpfile

    # Set the new narrowspec if we're widening. The setnewnarrowpats() method

    # will currently always be there when using the core+narrowhg server, but

    # other servers may include a changespec part even when not widening (e.g.

    # because we're deepening a shallow repo).

    if util.safehasattr(repo, 'setnewnarrowpats'):

        repo.setnewnarrowpats()

def handlechangegroup_widen(op, inpart):

    """Changegroup exchange handler which restores temporarily-stripped nodes"""

    # We saved a bundle with stripped node data we must now restore.

    # This approach is based on mercurial/repair.py@6ee26a53c111.

    repo = op.repo

    ui = op.ui

    chgrpfile = op._widen_bundle

    del op._widen_bundle

    vfs = repo.vfs

    ui.note(_(b"adding branch\n"))

    f = vfs.open(chgrpfile, b"rb")

    try:

        gen = exchange.readbundle(ui, f, chgrpfile, vfs)

        # silence internal shuffling chatter

        maybe_silent = (

            ui.silent() if not ui.verbose else util.nullcontextmanager()

        )

        with maybe_silent:

            if isinstance(gen, bundle2.unbundle20):

                with repo.transaction(b'strip') as tr:

                    bundle2.processbundle(repo, gen, lambda: tr)

            else:

                gen.apply(

                    repo, b'strip', b'bundle:' + vfs.join(chgrpfile), True

                )

    finally:

        f.close()

    # remove undo files

    for undovfs, undofile in repo.undofiles():

        try:

            undovfs.unlink(undofile)

        except OSError as e:

            if e.errno != errno.ENOENT:

                ui.warn(

                    _(b'error removing %s: %s\n')

                    % (undovfs.join(undofile), stringutil.forcebytestr(e))

                )

    # Remove partial backup only if there were no exceptions

    op._widen_uninterr.__exit__(None, None, None)

    vfs.unlink(chgrpfile)

def setup():

    """Enable narrow repo support in bundle2-related extension points."""

    getbundleargs = wireprototypes.GETBUNDLE_ARGUMENTS

    getbundleargs[b'narrow'] = b'boolean'

    getbundleargs[b'depth'] = b'plain'

    getbundleargs[b'oldincludepats'] = b'csv'

    getbundleargs[b'oldexcludepats'] = b'csv'

    getbundleargs[b'known'] = b'csv'

    # Extend changegroup serving to handle requests from narrow clients.

    origcgfn = exchange.getbundle2partsmapping[b'changegroup']

    def wrappedcgfn(*args, **kwargs):

        repo = args[1]

        if repo.ui.has_section(_NARROWACL_SECTION):

            kwargs = exchange.applynarrowacl(repo, kwargs)

        if kwargs.get('narrow', False) and repo.ui.configbool(

            b'experimental', b'narrowservebrokenellipses'

        ):

            getbundlechangegrouppart_narrow(*args, **kwargs)

        else:

            origcgfn(*args, **kwargs)

    exchange.getbundle2partsmapping[b'changegroup'] = wrappedcgfn

    # Extend changegroup receiver so client can fixup after widen requests.

    origcghandler = bundle2.parthandlermapping[b'changegroup']

    def wrappedcghandler(op, inpart):

        origcghandler(op, inpart)

        if util.safehasattr(op, '_widen_bundle'):

            handlechangegroup_widen(op, inpart)

        if util.safehasattr(op, '_bookmarksbackup'):

            localrepo.localrepository._bookmarks.set(

                op.repo, op._bookmarksbackup

            )

            del op._bookmarksbackup

    wrappedcghandler.params = origcghandler.params

    bundle2.parthandlermapping[b'changegroup'] = wrappedcghandler