# 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.

"""Introduce the Obsolete concept to mercurial

General concept

===============

This extension introduces the *obsolete* concept. It adds a new *obsolete*

relation between two changesets. A relation ``<changeset B> obsolete <changeset

A>`` is set to denote that ``<changeset B>`` is new version of ``<changeset

A>``.

The *obsolete* relation act as a **perpendicular history** to the standard

changeset history. Standard changeset history versions files. The *obsolete*

relation versions changesets.

:obsolete:     a changeset that have been replace by another one.

:out of sync:  a non-obsolet changeset based on another one.

:suspended:    an obsolete changeset with out of sync descendant.

Usage and Feature

=================

Display and Exchange

....................

obsolete changesets are hidden. (except if they have non obsolete changeset)

obsolete changesets are currently not exchange. This will probably change later

but it was the simpler solution for now.

New commands

............

a ``debugobsolete`` command has been added.

It add an obsolete relation between too relation.

Context object

..............

Context gain a ``obsolete`` method that return True if a changeset is obsolete

False otherwise.

revset

......

Add an ``obsolete()`` entry.

repo extension

..............

To Do

-----

* refuse to obsolete published changesets

* handle split

* handle conflict

* handle out of sync

"""

import os

try:

    from cStringIO import StringIO

except ImportError:

    from StringIO import StringIO

from mercurial import util

from mercurial import context

from mercurial import revset

from mercurial import scmutil

from mercurial import extensions

from mercurial import pushkey

from mercurial import discovery

from mercurial import error

from mercurial.node import hex, bin

from mercurial.lock import release

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

def obsolete(ctx):

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

    if ctx.node()is None:

        return False

    return bool(ctx._repo.obsoletedby(ctx.node()))

context.changectx.obsolete = obsolete

ohidden = context.changectx.hidden

def hidden(ctx):

    # hack to fill hiddenrevs

    # compute hidden (XXX should move elsewhere)

    if not getattr(ctx._repo.changelog, 'hiddeninit', False):

        basicquery = 'obsolete() - (ancestors(not obsolete() or . or bookmark()))'

        for rev in scmutil.revrange(ctx._repo, [basicquery]):

            ctx._repo.changelog.hiddenrevs.add(rev)

        ctx._repo.changelog.hiddeninit = True

    return ohidden(ctx)

context.changectx.hidden = hidden

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

def revsetobsolete(repo, subset, x):

    args = revset.getargs(x, 0, 0, 'publicheads takes no arguments')

    return [r for r in subset if repo[r].obsolete()] # XXX slow

### Other Extension compat

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

def concludenode(orig, repo, rev, *args, **kwargs):

    newrev = orig(repo, rev, *args, **kwargs)

    oldnode = repo[rev].node()

    newnode = repo[newrev].node()

    repo.addobsolete(newnode, oldnode)

    return newrev

def extsetup(ui):

    revset.symbols["obsolete"] = revsetobsolete

    def filterobsoleteout(orig, repo, remote, *args,**kwargs):

        common, heads = orig(repo, remote, *args, **kwargs)

        # filter obsolete

        heads = set(map(repo.changelog.rev, heads))

        obsoletes = set()

        for obj in repo._obsobjrels:

            try:

                obsoletes.add(repo.changelog.rev(obj))

            except error.LookupError:

                pass # we don't have this node locally

        outgoing = set(repo.changelog.ancestors(*heads))

        outgoing.update(heads)

        selected = outgoing - obsoletes

        heads = sorted(map(repo.changelog.node, selected))

        return common, heads

    extensions.wrapfunction(discovery, 'findcommonoutgoing', filterobsoleteout)

    try:

        rebase = extensions.find('rebase')

        if rebase:

            extensions.wrapfunction(rebase, 'concludenode', concludenode)

    except KeyError:

        pass # rebase not found

# Pushkey mechanism for mutable

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

def pushobsolete(repo, key, old, raw):

    assert key == "relations"

    w = repo.wlock()

    try:

        tmp = StringIO()

        tmp.write(raw)

        tmp.seek(0)

        relations = _obsdeserialise(tmp)

        for sub, objs in relations.iteritems():

            for obj in objs:

                try:

                    repo.addobsolete(sub, obj)

                except error.RepoLookupError:

                    pass

        return 0

    finally:

        w.release()

def listobsolete(repo):

    tmp = StringIO()

    _obsserialise(repo._obssubrels, tmp)

    return {'relations': tmp.getvalue()}

pushkey.register('obsolete', pushobsolete, listobsolete)

### 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>')}

### serialisation

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

def _obsserialise(obssubrels, flike):

    for sub, objs in obssubrels.iteritems():

        for obj in objs:

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

def _obsdeserialise(flike):

    rels = {}

    for line in flike:

        subhex, objhex = line.split()

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

    return rels

def reposetup(ui, repo):

    if not repo.local():

        return

    opull = repo.pull

    opush = repo.push

    orollback = repo.rollback

    o_writejournal = repo._writejournal

    class obsoletingrepo(repo.__class__):

        ### Public method

        def obsoletedby(self, node):

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

            return self._obsobjrels.get(node, set())

        def obsolete(self, node):

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

            return self._obssubrels.get(node, set())

        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)

            try:

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

            except error.RepoLookupError:

                pass #unknow revision (but keep propagating the data

            self._writeobsrels()

        ### Hidden revision support

        @util.propertycache

        def hiddenrevs(self):

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

            revs = set()

            return revs

        ### obsolete storage

        @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)

            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

            try:

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

                try:

                    return _obsdeserialise(f)

                finally:

                    f.close()

            except IOError:

                return {}

        def _writeobsrels(self):

            """Write obsolete relation on disk"""

            # XXX handle lock

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

            try:

                _obsserialise(self._obssubrels, f)

                f.rename()

            finally:

                f.close()

        ### local clone support

        def cancopy(self):

            return not bool(self._obsobjrels) # you can't copy if there is obsolete

        ### pull // push support

        def pull(self, remote, *args, **kwargs):

            result = opull(remote, *args, **kwargs)

            if 'obsolete' in remote.listkeys('namespaces'):

                tmp = StringIO()

                tmp.write(remote.listkeys('obsolete')['relations'])

                tmp.seek(0)

                obsrels = _obsdeserialise(tmp)

                for sub, objs in obsrels.iteritems():

                    for obj in objs:

                        self.addobsolete(sub, obj)

            return result

        def push(self, remote, *args, **opts):

            result = opush(remote, *args, **opts)

            if 'obsolete' in remote.listkeys('namespaces'):

                tmp = StringIO()

                _obsserialise(self._obssubrels, tmp)

                remote.pushkey('obsolete', 'relations', '', tmp.getvalue())

            return result

        ### rollback support

        def _writejournal(self, desc):

            entries = list(o_writejournal(desc))

            filename = 'obsolete-relations'

            filepath = self.join(filename)

            if  os.path.exists(filepath):

                journalname = 'journal.' + filename

                journalpath = self.join(journalname)

                util.copyfile(filepath, journalpath)

                entries.append(journalpath)

            return tuple(entries)

        def rollback(self, dryrun=False):

            wlock = lock = None

            try:

                wlock = self.wlock()

                lock = self.lock()

                ret = orollback(dryrun)

                if not (ret or dryrun): #rollback did not failed

                    src = self.join('undo.obsolete-relations')

                    dst = self.join('obsolete-relations')

                    if os.path.exists(src):

                        util.rename(src, dst)

                    elif os.path.exists(dst): #unlink in any case

                        os.unlink(dst)

                    # invalidate cache

                    self.__dict__.pop('_obssubrels', None)

                    self.__dict__.pop('_obsobjrels', None)

                return ret

            finally:

                release(lock, wlock)

    repo.__class__ = obsoletingrepo