# narrowmerge.py - extensions to mercurial merge module to support narrow clones

#

# 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 (

    copies,

    error,

    extensions,

    merge,

)

def setup():

    def _manifestmerge(orig, repo, wctx, p2, pa, branchmerge, *args, **kwargs):

        """Filter updates to only lay out files that match the narrow spec."""

        actions, diverge, renamedelete = orig(

            repo, wctx, p2, pa, branchmerge, *args, **kwargs)

        narrowmatch = repo.narrowmatch()

        if narrowmatch.always():

            return actions, diverge, renamedelete

        nooptypes = set(['k']) # TODO: handle with nonconflicttypes

        nonconflicttypes = set('a am c cm f g r e'.split())

        # We mutate the items in the dict during iteration, so iterate

        # over a copy.

        for f, action in list(actions.items()):

            if narrowmatch(f):

                pass

            elif not branchmerge:

                del actions[f] # just updating, ignore changes outside clone

            elif action[0] in nooptypes:

                del actions[f] # merge does not affect file

            elif action[0] in nonconflicttypes:

                raise error.Abort(_('merge affects file \'%s\' outside narrow, '

                                    'which is not yet supported') % f,

                                  hint=_('merging in the other direction '

                                         'may work'))

            else:

                raise error.Abort(_('conflict in file \'%s\' is outside '

                                    'narrow clone') % f)

        return actions, diverge, renamedelete

    extensions.wrapfunction(merge, 'manifestmerge', _manifestmerge)

    def _checkcollision(orig, repo, wmf, actions):

        narrowmatch = repo.narrowmatch()

        if not narrowmatch.always():

            wmf = wmf.matches(narrowmatch)

            if actions:

                narrowactions = {}

                for m, actionsfortype in actions.iteritems():

                    narrowactions[m] = []

                    for (f, args, msg) in actionsfortype:

                        if narrowmatch(f):

                            narrowactions[m].append((f, args, msg))

                actions = narrowactions

        return orig(repo, wmf, actions)

    extensions.wrapfunction(merge, '_checkcollision', _checkcollision)

    def _computenonoverlap(orig, repo, *args, **kwargs):

        u1, u2 = orig(repo, *args, **kwargs)

        narrowmatch = repo.narrowmatch()

        if narrowmatch.always():

            return u1, u2

        u1 = [f for f in u1 if narrowmatch(f)]

        u2 = [f for f in u2 if narrowmatch(f)]

        return u1, u2

    extensions.wrapfunction(copies, '_computenonoverlap', _computenonoverlap)