'''enable experimental obsolescence feature of Mercurial

OBSOLESCENCE IS AN EXPERIMENTAL FEATURE MAKE SURE YOU UNDERSTOOD THE INVOLVED

CONCEPT BEFORE USING IT.

/!\ THIS EXTENSION IS INTENDED FOR SERVER SIDE ONLY USAGE /!\

For client side usages it is recommended to use the evolve extension for

improved user interface.'''

testedwith = '2.9.1'

buglink = 'https://bitbucket.org/marmoute/mutable-history/issues'

import mercurial.obsolete

mercurial.obsolete._enabled = True

import struct

from mercurial import util

from mercurial import wireproto

from mercurial import extensions

from mercurial import obsolete

from cStringIO import StringIO

from mercurial import node

from mercurial.hgweb import hgweb_mod

_pack = struct.pack

# from evolve extension: 1a23c7c52a43

def srv_pushobsmarkers(repo, proto):

    """That receives a stream of markers and apply then to the repo"""

    fp = StringIO()

    proto.redirect()

    proto.getfile(fp)

    data = fp.getvalue()

    fp.close()

    lock = repo.lock()

    try:

        tr = repo.transaction('pushkey: obsolete markers')

        try:

            repo.obsstore.mergemarkers(tr, data)

            tr.close()

        finally:

            tr.release()

    finally:

        lock.release()

    return wireproto.pushres(0)

# from mercurial.obsolete: 19e9478c1a22

def _encodemarkersstream(fp, markers):

    """write a binary version of a set of markers

    Includes the initial version number"""

    fp.write(_pack('>B', 0))

    for mark in markers:

        fp.write(obsolete._encodeonemarker(mark))

# from evolve extension: 1a23c7c52a43

def _getobsmarkersstream(repo, heads=None, common=None):

    """Get a binary stream for all markers relevant to `::<heads> - ::<common>`

    """

    revset = ''

    args = []

    repo = repo.unfiltered()

    if heads is None:

        revset = 'all()'

    elif heads:

        revset += "(::%ln)"

        args.append(heads)

    else:

        assert False, 'pulling no heads?'

    if common:

        revset += ' - (::%ln)'

        args.append(common)

    nodes = [c.node() for c in repo.set(revset, *args)]

    markers = repo.obsstore.relevantmarkers(nodes)

    obsdata = StringIO()

    _encodemarkersstream(obsdata, markers)

    obsdata.seek(0)

    return obsdata

# from evolve extension: 1a23c7c52a43

class pruneobsstore(obsolete.obsstore):

    """And extended obsstore class that read parent information from v1 format

    Evolve extension adds parent information in prune marker. We use it to make

    markers relevant to pushed changeset."""

    def __init__(self, *args, **kwargs):

        self.prunedchildren = {}

        return super(pruneobsstore, self).__init__(*args, **kwargs)

    def _load(self, markers):

        markers = self._prunedetectingmarkers(markers)

        return super(pruneobsstore, self)._load(markers)

    def _prunedetectingmarkers(self, markers):

        for m in markers:

            if not m[1]: # no successors

                meta = obsolete.decodemeta(m[3])

                if 'p1' in meta:

                    p1 = node.bin(meta['p1'])

                    self.prunedchildren.setdefault(p1, set()).add(m)

                if 'p2' in meta:

                    p2 = node.bin(meta['p2'])

                    self.prunedchildren.setdefault(p2, set()).add(m)

            yield m

# from evolve extension: 1a23c7c52a43

def relevantmarkers(self, nodes):

    """return a set of all obsolescence marker relevant to a set of node.

    "relevant" to a set of node mean:

    - marker that use this changeset as successors

    - prune marker of direct children on this changeset.

    - recursive application of the two rules on precursors of these markers

    It is a set so you cannot rely on order"""

    seennodes = set(nodes)

    seenmarkers = set()

    pendingnodes = set(nodes)

    precursorsmarkers = self.precursors

    prunedchildren = self.prunedchildren

    while pendingnodes:

        direct = set()

        for current in pendingnodes:

            direct.update(precursorsmarkers.get(current, ()))

            direct.update(prunedchildren.get(current, ()))

        direct -= seenmarkers

        pendingnodes = set([m[0] for m in direct])

        seenmarkers |= direct

        pendingnodes -= seennodes

        seennodes |= pendingnodes

    return seenmarkers

# from evolve extension: 1a23c7c52a43

def srv_pullobsmarkers(repo, proto, others):

    """serves a binary stream of markers.

    Serves relevant to changeset between heads and common. The stream is prefix

    by a -string- representation of an integer. This integer is the size of the

    stream."""

    opts = wireproto.options('', ['heads', 'common'], others)

    for k, v in opts.iteritems():

        if k in ('heads', 'common'):

            opts[k] = wireproto.decodelist(v)

    obsdata = _getobsmarkersstream(repo, **opts)

    length = '%20i' % len(obsdata.getvalue())

    def data():

        yield length

        for c in proto.groupchunks(obsdata):

            yield c

    return wireproto.streamres(data())

# from evolve extension: 1a23c7c52a43

def _obsrelsethashtree(repo):

    """Build an obshash for every node in a repo

    return a [(node), (obshash)] list. in revision order."""

    cache = []

    unfi = repo.unfiltered()

    for i in unfi:

        ctx = unfi[i]

        entry = 0

        sha = util.sha1()

        # add data from p1

        for p in ctx.parents():

            p = p.rev()

            if p < 0:

                p = node.nullid

            else:

                p = cache[p][1]

            if p != node.nullid:

                entry += 1

                sha.update(p)

        tmarkers = repo.obsstore.relevantmarkers([ctx.node()])

        if tmarkers:

            bmarkers = [obsolete._encodeonemarker(m) for m in tmarkers]

            bmarkers.sort()

            for m in bmarkers:

                entry += 1

                sha.update(m)

        if entry:

            cache.append((ctx.node(), sha.digest()))

        else:

            cache.append((ctx.node(), node.nullid))

    return cache

# from evolve extension: 1a23c7c52a43

def _obshash(repo, nodes):

    """hash of binary version of relevant markers + obsparent

    (special case so that all empty are hashed as nullid)"""

    hashs = _obsrelsethashtree(repo)

    nm = repo.changelog.nodemap

    return  [hashs[nm.get(n)][1] for n in nodes]

# from evolve extension: 1a23c7c52a43

def srv_obshash(repo, proto, nodes):

    """give the obshash of a a set of node

    Used for markes discovery"""

    return wireproto.encodelist(_obshash(repo, wireproto.decodelist(nodes)))

# from evolve extension: 1a23c7c52a43

def capabilities(orig, repo, proto):

    """wrapper to advertise new capability"""

    caps = orig(repo, proto)

    if obsolete._enabled:

        caps += ' _evoext_pushobsmarkers_0'

        caps += ' _evoext_pullobsmarkers_0'

        caps += ' _evoext_obshash_0'

    return caps

# heavily modified

def extsetup(ui):

    obsolete.obsstore = pruneobsstore

    obsolete.obsstore.relevantmarkers = relevantmarkers

    hgweb_mod.perms['evoext_pushobsmarkers_0'] = 'push'

    hgweb_mod.perms['evoext_pullobsmarkers_0'] = 'pull'

    hgweb_mod.perms['evoext_obshash'] = 'pull'

    wireproto.commands['evoext_pushobsmarkers_0'] = (srv_pushobsmarkers, '')

    wireproto.commands['evoext_pullobsmarkers_0'] = (srv_pullobsmarkers, '*')

    # wrap module content

    extensions.wrapfunction(wireproto, 'capabilities', capabilities)

    # wrap command content

    oldcap, args = wireproto.commands['capabilities']

    def newcap(repo, proto):

        return capabilities(oldcap, repo, proto)

    wireproto.commands['capabilities'] = (newcap, args)

    wireproto.commands['evoext_obshash'] = (srv_obshash, 'nodes')