# 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.

:unstable:     a non-obsolet changeset based on another one.

:suspended:    an obsolete changeset with unstable descendant.

Another name for unstable could be out of sync.

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Context gain a ``obsolete`` method that return True if a changeset is obsolete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 unstable // out of sync

"""

import os

try:

    from cStringIO import StringIO

except ImportError:

    from StringIO import StringIO

from mercurial.i18n import _

import base64

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 import commands

from mercurial import changelog

from mercurial import phases

from mercurial.node import hex, bin, short, nullid

from mercurial.lock import release

### Patch changectx

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

def obsolete(ctx):

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

    if ctx.node()is None:

        return False

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

context.changectx.obsolete = obsolete

### revset

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

def revsetobsolete(repo, subset, x):

    """filter obsolet entry"""

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

    return [r for r in subset if r in repo._obsoleteset and repo._phaserev[r] > 0]

### Other Extension compat

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

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

    """wrapper for rebase 's concludenode that set obsolete relation"""

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

    oldnode = repo[rev].node()

    newnode = repo[newrev].node()

    repo.addobsolete(newnode, oldnode)

    return newrev

def cmdrebase(orig, repo, ui, *args, **kwargs):

    oldkeep = kwargs.pop('keep', False)

    if oldkeep:

        ui.warn('WARNING --keep option ignored by experimental obsolete extension')

    kwargs['keep'] = True

    return orig(repo, ui, *args, **kwargs)

### Filter obsolet changeset

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

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

    """wrapper for findcommonoutgoing that remove obsolete changeset

    This behaviour is temporary"""

    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

def extsetup(ui):

    revset.symbols["obsolete"] = revsetobsolete

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

    try:

        rebase = extensions.find('rebase')

        if rebase:

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

            extensions.wrapcommand(rebase.cmdtable, "rebase", cmdrebase)

    except KeyError:

        pass # rebase not found

# Pushkey mechanism for mutable

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

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

    """push obsolete relation through pushkey"""

    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):

    """dump all obsolete relation in

    XXX this have be improved"""

    tmp = StringIO()

    _obsserialise(repo._obssubrels, tmp)

    return {'relations': base64.b64encode(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>')}

### Altering existing command

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

def wrapmayobsoletewc(origfn, ui, repo, *args, **opts):

    res = origfn(ui, repo, *args, **opts)

    if repo['.'].obsolete():

        ui.warn(_('Working directory parent is obsolete\n'))

    return res

def uisetup(ui):

    extensions.wrapcommand(commands.table, "update", wrapmayobsoletewc)

    extensions.wrapcommand(commands.table, "pull", wrapmayobsoletewc)

### serialisation

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

def _obsserialise(obssubrels, flike):

    """serialise an obsolete relation mapping in a plain text one

    this is for subject -> [objects] mapping

    format is::

        <subject-full-hex> <object-full-hex>\n"""

    for sub, objs in obssubrels.iteritems():

        for obj in objs:

            if sub is None:

                sub = nullid

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

def _obsdeserialise(flike):

    """read a file like object serialised with _obsserialise

    this desierialize into a {subject -> objects} mapping"""

    rels = {}

    for line in flike:

        subhex, objhex = line.split()

        subnode = bin(subhex)

        if subnode == nullid:

            subnode = None

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

    return rels

### diagnostique tools

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

def unstables(repo):

    """Return all unstable changeset"""

    return scmutil.revrange(repo, ['obsolete():: and (not obsolete())'])

def newerversion(repo, obs):

    """Return the newer version of an obsolete changeset"""

    toproceed = set([obs])

    # XXX know optimization available

    newer = set()

    while toproceed:

        current = toproceed.pop()

        if current in repo._obsobjrels:

            toproceed.update(repo._obsobjrels[current])

        elif current is not None: # None is kill

            newer.add(current)

    return sorted(newer)

### repo subclassing

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

def reposetup(ui, repo):

    if not repo.local():

        return

    opull = repo.pull

    opush = repo.push

    orollback = repo.rollback

    o_writejournal = repo._writejournal

    ocancopy = repo.cancopy

    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())

        @util.propertycache

        def _obsoleteset(self):

            obs = set()

            for obj in self._obsobjrels:

            return obs

        def addobsolete(self, sub, obj):

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

            if sub == nullid:

                sub = None

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

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

            try:

                if self[obj].phase() == 0:

                    if sub is None:

                        self.ui.warn(

                            _("trying to kill immutable changeset %(obj)s\n")

                            % {'obj': short(obj)})

                    if sub is not None:

                        self.ui.warn(

                            _("%(sub)s try to obsolete immutable changeset %(obj)s\n")

                            % {'sub': short(sub), 'obj': short(obj)})

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

            except (error.RepoLookupError, error.LookupError):

                pass #unknow revision (but keep propagating the data

            self._writeobsrels()

            if '_obsobjrels' in vars(self):

                del self._obsobjrels

            if '_obssubrels' in vars(self):

                del self._obssubrels

            if '_obsoleteset' in vars(self):

                del self._obsoleteset

        ### 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

            lock = self.wlock()

            try:

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

                try:

                    _obsserialise(self._obssubrels, f)

                    try:

                        f.rename()

                    except AttributeError: # old version

                        f.close()

                finally:

                    f.close()