# 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.
:extinct:      an obsolete changeset without unstable descendant
               (subject to garbage collection)

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Context gain a ``obsolete`` method that return True if a changeset is obsolete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

try:
    from mercurial.localrepo import storecache
    storecache('babar') # to trigger import
except (TypeError, ImportError):
    def storecache(*args):
        return scmutil.filecache(*args, instore=True)


### 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

def unstable(ctx):
    """is the changeset unstable (have obsolete ancestor)"""
    if ctx.node() is None:
        return False
    return ctx.rev() in ctx._repo._unstableset

context.changectx.unstable = unstable

def extinct(ctx):
    """is the changeset extinct by other"""
    if ctx.node() is None:
        return False
    return ctx.rev() in ctx._repo._extinctset

context.changectx.extinct = extinct


### revset
#############################


def revsetobsolete(repo, subset, x):
    """obsolete changesets"""
    args = revset.getargs(x, 0, 0, 'obsolete takes no argument')
    return [r for r in subset if r in repo._obsoleteset and repo._phaserev[r] > 0]

def revsetunstable(repo, subset, x):
    """non obsolete changesets descendant of obsolete one"""
    args = revset.getargs(x, 0, 0, 'unstable takes no arguments')
    return [r for r in subset if r in repo._unstableset]

def revsetsuspended(repo, subset, x):
    """obsolete changesets with non obsolete descendants"""
    args = revset.getargs(x, 0, 0, 'unstable takes no arguments')
    return [r for r in subset if r in repo._suspendedset]

def revsetextinct(repo, subset, x):
    """obsolete changesets without obsolete descendants"""
    args = revset.getargs(x, 0, 0, 'unstable takes no arguments')
    return [r for r in subset if r in repo._extinctset]


def _obsparents(repo, s):
    """obsolete parents of a subset"""
    cs = set()
    nm = repo.changelog.nodemap
    for r in s:
        for p in repo._obssubrels.get(repo[r].node(), ()):
            pr = nm.get(p)
            if pr is not None:
                cs.add(pr)
    return cs

def revsetobsparents(repo, subset, x):
    """obsolete parents"""
    s = revset.getset(repo, range(len(repo)), x)
    cs = _obsparents(repo, s)
    return [r for r in subset if r in cs]

def _obsancestors(repo, s):
    """obsolete ancestors of a subset"""
    toproceed = [repo[r].node() for r in s]
    seen = set()
    while toproceed:
        nc = toproceed.pop()
        for np in repo._obssubrels.get(nc, ()):
            if np not in seen:
                seen.add(np)
                toproceed.append(np)
    nm = repo.changelog.nodemap
    cs = set()
    for p in seen:
        pr = nm.get(p)
        if pr is not None:
            cs.add(pr)
    return cs

def revsetobsancestors(repo, subset, x):
    """obsolete parents"""
    s = revset.getset(repo, range(len(repo)), x)
    cs = _obsancestors(repo, s)
    return [r for r in subset if r in cs]



### Other Extension compat
############################


def buildstate(orig, repo, dest, rebaseset, detach):
    """wrapper for rebase 's buildstate that exclude obsolete changeset"""
    rebaseset = repo.revs('%ld - extinct()', rebaseset)
    return orig(repo, dest, rebaseset, detach)


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)



def extsetup(ui):

    revset.symbols["obsolete"] = revsetobsolete
    revset.symbols["unstable"] = revsetunstable
    revset.symbols["suspended"] = revsetsuspended
    revset.symbols["extinct"] = revsetextinct
    revset.symbols["obsparents"] = revsetobsparents
    revset.symbols["obsancestors"] = revsetobsancestors


    try:
        rebase = extensions.find('rebase')
        if rebase:
            extensions.wrapfunction(rebase, 'buildstate', buildstate)
            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)

### Discovery wrapping
#############################

class blist(list, object):
    """silly class to have non False but empty list"""

    def __nonzero__(self):
        return bool(len(self.orig))

def wrapfindcommonoutgoing(orig, repo, *args, **kwargs):
    """wrap mercurial.discovery.findcommonoutgoing to remove extinct changeset

    Such excluded changeset are removed from excluded  and will *not* appear
    are excluded secret changeset.
    """
    outgoing = orig(repo, *args, **kwargs)
    orig = outgoing.excluded
    outgoing.excluded = blist(n for n in orig if not repo[n].extinct())
    # when no revision is specified (push everything) a shortcut is taken when
    # nothign was exclude. taking this code path when extinct changeset have
    # been excluded leads to repository corruption.
    outgoing.excluded.orig = orig
    return outgoing

### 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)
    extensions.wrapfunction(discovery, 'findcommonoutgoing', wrapfindcommonoutgoing)

### 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,))
        else:
            newer.add(())
    return sorted(newer)


### repo subclassing
#############################

def reposetup(ui, repo):

    if not repo.local():
        return

    opull = repo.pull
    opush = repo.push
    o_rollback = repo._rollback
    o_updatebranchcache = repo.updatebranchcache

    # /!\ api change in  Hg 2.2 (97efd26eb9576f39590812ea9) /!\
    if util.safehasattr(repo, '_journalfiles'): # Hg 2.2
        o_journalfiles = repo._journalfiles
    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())

        @util.propertycache
        def _obsoleteset(self):
            """the set of obsolete revision"""
            obs = set()
            nm = self.changelog.nodemap
            for obj in self._obsobjrels:
                try: # /!\api change in Hg 2.2 (e8d37b78acfb22ae2c1fb126c2)/!\
                    rev = nm.get(obj)
                except TypeError:  #XXX to remove while breaking Hg 2.1 support
                    rev = nm.get(obj, None)
                if rev is not None:
                    obs.add(rev)
            return obs

        @util.propertycache
        def _unstableset(self):
            """the set of non obsolete revision with obsolete parent"""
            return set(self.revs('(obsolete()::) - obsolete()'))

        @util.propertycache
        def _suspendedset(self):
            """the set of obsolete parent with non obsolete descendant"""
            return set(self.revs('obsolete() and obsolete()::unstable()'))

        @util.propertycache
        def _extinctset(self):
            """the set of obsolete parent without non obsolete descendant"""
            return set(self.revs('obsolete() - obsolete()::unstable()'))

        def _clearobsoletecache(self):
            if '_obsobjrels' in vars(self):
                del self._obsobjrels
            if '_obssubrels' in vars(self):
                del self._obssubrels
            if '_obsoleteset' in vars(self):
                del self._obsoleteset
            self._clearunstablecache()

        def updatebranchcache(self):
            o_updatebranchcache()
            self._clearunstablecache()

        def _clearunstablecache(self):
            if '_unstableset' in vars(self):
                del self._unstableset
            if '_suspendedset' in vars(self):
                del self._suspendedset
            if '_extinct' in vars(self):
                del self._extinctset

        def addobsolete(self, sub, obj):
            """Add a relation marking that node <sub> is a new version of <obj>"""
            if sub == nullid:
                sub = None
            if obj in self._obssubrels.get(sub, set()):
                return 0
            if sub == obj:
                return 0
            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()
            self._clearobsoletecache()
            return 1

        ### 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()
            finally:
                lock.release()


        ### pull // push support

        def pull(self, remote, *args, **kwargs):
            """wrapper around push that push obsolete relation"""
            result = opull(remote, *args, **kwargs)
            if 'obsolete' in remote.listkeys('namespaces'):
                tmp = StringIO()
                rels = remote.listkeys('obsolete')['relations']
                tmp.write(base64.b64decode(rels))
                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):
            """wrapper around pull that pull obsolete relation"""
            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

        # /!\ api change in  Hg 2.2 (97efd26eb9576f39590812ea9) /!\
        if util.safehasattr(repo, '_journalfiles'): # Hg 2.2
            def _journalfiles(self):
                return o_journalfiles() + (self.join('journal.obsolete-relations'),) 

            def _writejournal(self, desc):
                """wrapped version of _writejournal that save obsolete data"""
                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)

        else: # XXX remove this bloc while breaking support to Hg 2.1
            def _writejournal(self, desc):
                """wrapped version of _writejournal that save obsolete data"""
                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, force):
            """wrapped version of _rollback that restore obsolete data"""
            ret = o_rollback(dryrun, force)
            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):
                    # If no state was saved because the file did not existed before.
                    os.unlink(dst)
                # invalidate cache
                self.__dict__.pop('_obssubrels', None)
                self.__dict__.pop('_obsobjrels', None)
            return ret

        @storecache('00changelog.i')
        def changelog(self):
            # << copy pasted from mercurila source
            c = changelog.changelog(self.sopener)
            if 'HG_PENDING' in os.environ:
                p = os.environ['HG_PENDING']
                if p.startswith(self.root):
                    c.readpending('00changelog.i.a')
            # >> end of the copy paste
            old = c.__dict__.pop('hiddenrevs', ())
            if old:
                ui.warn("old wasn't empty ? %r" % old)
            def _sethidden(c, value):
                assert not value


            class hchangelog(c.__class__):
                @util.propertycache
                def hiddenrevs(c):
                    shown = ['not obsolete()', '.', 'bookmark()', 'tagged()',
                             'public()']
                    basicquery = 'obsolete() - (::(%s))' % (' or '.join(shown))
                    # !!! self is repo not changelog
                    result = set(scmutil.revrange(self, [basicquery]))
                    return result
            c.__class__ = hchangelog
            return c




    repo.__class__ = obsoletingrepo
    if repo.ui.configbool('obsolete', 'secret-unstable', True):
        symbol = 'obsolete()'
    else:
        symbol = 'extinct()'

    expobs = [c.node() for c in repo.set('%s - secret()' % symbol)]
    if expobs: # do not lock in nothing move. locking for peanut make hgview reload on any command
        lock = repo.lock()
        try:
            phases.retractboundary(repo, 2, expobs)
        finally:
            lock.release()