# topic/server.py - server specific behavior with topic

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

from mercurial import (

    extensions,

    repoview,

    repoviewutil,

    wireprototypes,

    wireprotov1peer,

    wireprotov1server,

)

from . import (

    common,

    constants,

)

### Visibility restriction

#

# Serving draft changesets with topics to clients without topic extension can

# confuse them, because they won't see the topic label and will consider them

# normal anonymous heads. Instead we have the option to not serve changesets

# with topics to clients without topic support.

#

# To achieve this, we alter the behavior of the standard `heads` commands and

# introduce a new `heads` command that only clients with topic will know about.

# compat version of the wireprotocommand decorator, taken from evolve compat

FILTERNAME = b'served-no-topic'

def computeunservedtopic(repo, visibilityexceptions=None):

    assert not repo.changelog.filteredrevs

    filteredrevs = repoview.filtertable[b'served'](repo, visibilityexceptions).copy()

    mutable = repoview.filtertable[b'immutable'](repo, visibilityexceptions)

    consider = mutable - filteredrevs

    cl = repo.changelog

    extrafiltered = set()

    for r in consider:

        if cl.changelogrevision(r).extra.get(constants.extrakey, b''):

            extrafiltered.add(r)

    if extrafiltered:

        filteredrevs = frozenset(filteredrevs | extrafiltered)

    return filteredrevs

def wireprotocommand(name, args=b'', permission=b'pull'):

    try:

        from mercurial.wireprotov1server import wireprotocommand

    except (ImportError, AttributeError):

        # hg <= 4.6 (b4d85bc122bd)

        from mercurial.wireproto import wireprotocommand

    return wireprotocommand(name, args, permission=permission)

def wrapheads(orig, repo, proto):

    """wrap head to hide topic^W draft changeset to old client"""

    hidetopics = repo.ui.configbool(b'experimental', b'topic.server-gate-topic-changesets')

    if common.hastopicext(repo) and hidetopics:

        h = repo.filtered(FILTERNAME).heads()

        return wireprototypes.bytesresponse(wireprototypes.encodelist(h) + b'\n')

    return orig(repo, proto)

def topicheads(repo, proto):

    """Same as the normal wireprotocol command, but accessing with a different end point."""

    h = repo.heads()

    return wireprototypes.bytesresponse(wireprototypes.encodelist(h) + b'\n')

def wireprotocaps(orig, repo, proto):

    """advertise the new topic specific `head` command for client with topic"""

    caps = orig(repo, proto)

    if common.hastopicext(repo) and repo.peer().capable(b'topics'):

        caps.append(b'_exttopics_heads')

    return caps

def setupserver(ui):

    extensions.wrapfunction(wireprotov1server, 'heads', wrapheads)

    wireprotov1server.commands.pop(b'heads')

    wireprotocommand(b'heads', permission=b'pull')(wireprotov1server.heads)

    wireprotocommand(b'_exttopics_heads', permission=b'pull')(topicheads)

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

    class topicpeerexecutor(wireprotov1peer.peerexecutor):

        def callcommand(self, command, args):

            if command == b'heads':

                if self._peer.capable(b'_exttopics_heads'):

                    command = b'_exttopics_heads'

                    if getattr(self._peer, '_exttopics_heads', None) is None:

                        self._peer._exttopics_heads = self._peer.heads

            s = super(topicpeerexecutor, self)

            return s.callcommand(command, args)

    wireprotov1peer.peerexecutor = topicpeerexecutor

    if FILTERNAME not in repoview.filtertable:

        repoview.filtertable[FILTERNAME] = computeunservedtopic

        repoviewutil.subsettable[FILTERNAME] = b'immutable'

        repoviewutil.subsettable[b'served'] = FILTERNAME