# obsolete.py - introduce the obsolete concept in mercurial.

#

# Copyright 2011 Pierre-Yves David <pierre-yves.david@ens-lyon.org>

#                Logilab SA        <contact@logilab.fr>

#

# 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 util

from mercurial import context

from mercurial.node import hex, bin

# Patch changectx

#############################

def obsolete(ctx):

    """is the changeset obsolete by other"""

    if ctx.node()is None:

        return False

context.changectx.obsolete = obsolete

ohidden = context.changectx.hidden

def hidden(ctx):

    ctx._repo._obsobjrels # XXX hack to fill hiddenrevs

    return ohidden(ctx)

context.changectx.hidden = hidden

# New commands

#############################

def cmddebugobsolete(ui, repo, subject, object):

    """Add an obsolete relation between a too node

    The subject is expected to be a newer version of the object"""

    sub = repo[subject]

    obj = repo[object]

    repo.addobsolete(sub.node(), obj.node())

    return 0

cmdtable = {'debugobsolete': (cmddebugobsolete, [], '<subject> <object>')}

def reposetup(ui, repo):

    class obsoletingrepo(repo.__class__):

        @util.propertycache

        def hiddenrevs(self):

            # It's a property because It simpler that to handle the __init__

            revs = set()

            return revs

        @util.propertycache

        def _obsobjrels(self):

            """{<old-node> -> set(<new-node>)}

            also compute hidden revision"""

            #reverse sub -> objs mapping

            objrels = {}

            for sub, objs in self._obssubrels.iteritems():

                for obj in objs:

                    objrels.setdefault(obj, set()).add(sub)

            # compute hidden (XXX should move elsewhere)

            for obj in objrels:

                self.changelog.hiddenrevs.add(repo[obj].rev())

            #

            return objrels

        @util.propertycache

        def _obssubrels(self):

            """{<new-node> -> set(<old-node>)}"""

            return self._readobsrels()

        ### Disk IO

        def _readobsrels(self):

            """Write obsolete relation on disk"""

            # XXX handle lock

            rels = {}

            try:

                f = self.opener('obsolete-relations')

                try:

                    for line in f:

                        subhex, objhex = line.split()

                        rels.setdefault(bin(subhex), set()).add(bin(objhex))

                finally:

                    f.close()

            except IOError:

                pass

            return rels

        def _writeobsrels(self):

            """Write obsolete relation on disk"""

            # XXX handle lock

            f = self.opener('obsolete-relations', 'w', atomictemp=True)

            try:

                for sub, objs in self._obssubrels.iteritems():

                    for obj in objs:

                        f.write('%s %s\n' % (hex(sub), hex(obj)))

                f.rename()

            finally:

                f.close()

        ### Public method

        def obsoletedby(self, node):

            """return the set of node that make <node> obsolete (obj)"""

        def obsolete(self, node):

            """return the set of node that <node> make obsolete (sub)"""

        def addobsolete(self, sub, obj):

            """Add a relation marking that node <sub> is a new version of <obj>"""

            self._obssubrels.setdefault(sub, set()).add(obj)

            self._obsobjrels.setdefault(obj, set()).add(sub)

            self.changelog.hiddenrevs.add(repo[obj].rev())

            self._writeobsrels()

    repo.__class__ = obsoletingrepo