# repair.py - functions for repository repair for mercurial

#

# Copyright 2005, 2006 Chris Mason <mason@suse.com>

# Copyright 2007 Matt Mackall

#

# This software may be used and distributed according to the terms

# of the GNU General Public License, incorporated herein by reference.

import changegroup, os

from node import *

def _limitheads(cl, stoprev):

    """return the list of all revs >= stoprev that have no children"""

    seen = {}

    heads = []

    for r in xrange(cl.count() - 1, stoprev - 1, -1):

        if r not in seen:

            heads.append(r)

        for p in cl.parentrevs(r):

            seen[p] = 1

    return heads

def _bundle(repo, bases, heads, node, suffix, extranodes=None):

    """create a bundle with the specified revisions as a backup"""

    cg = repo.changegroupsubset(bases, heads, 'strip', extranodes)

    backupdir = repo.join("strip-backup")

    if not os.path.isdir(backupdir):

        os.mkdir(backupdir)

    name = os.path.join(backupdir, "%s-%s" % (short(node), suffix))

    repo.ui.warn("saving bundle to %s\n" % name)

    return changegroup.writebundle(cg, name, "HG10BZ")

    for x in xrange(striprev, repo.changelog.count()):

        for name in repo.changectx(x).files():

                continue

def _collectextranodes(repo, files, link):

    """return the nodes that have to be saved before the strip"""

    def collectone(revlog):

        extra = []

        startrev = count = revlog.count()

        # find the truncation point of the revlog

        for i in xrange(0, count):

            node = revlog.node(i)

            lrev = revlog.linkrev(node)

            if lrev >= link:

                startrev = i + 1

                break

        # see if any revision after that point has a linkrev less than link

        # (we have to manually save these guys)

        for i in xrange(startrev, count):

            node = revlog.node(i)

            lrev = revlog.linkrev(node)

            if lrev < link:

                extra.append((node, cl.node(lrev)))

        return extra

    extranodes = {}

    cl = repo.changelog

    extra = collectone(repo.manifest)

    if extra:

        extranodes[1] = extra

    for fname in files:

        f = repo.file(fname)

        extra = collectone(f)

        if extra:

            extranodes[fname] = extra

    return extranodes

def strip(ui, repo, node, backup="all"):

    cl = repo.changelog

    # TODO delete the undo files, and handle undo of merge sets

    pp = cl.parents(node)

    striprev = cl.rev(node)

    # save is a list of all the branches we are truncating away

    # that we actually want to keep.  changegroup will be used

    # to preserve them and add them back after the truncate

    saveheads = []

    savebases = {}

    heads = [cl.node(r) for r in _limitheads(cl, striprev)]

    seen = {}

    # search through all the heads, finding those where the revision

    # we want to strip away is an ancestor.  Also look for merges

    # that might be turned into new heads by the strip.

    while heads:

        h = heads.pop()

        n = h

        while True:

            seen[n] = 1

            pp = cl.parents(n)

            if pp[1] != nullid:

                for p in pp:

                    if cl.rev(p) > striprev and p not in seen:

                        heads.append(p)

            if pp[0] == nullid:

                break

            if cl.rev(pp[0]) < striprev:

                break

            n = pp[0]

            if n == node:

                break

        r = cl.reachable(h, node)

        if node not in r:

            saveheads.append(h)

            for x in r:

                if cl.rev(x) > striprev:

                    savebases[x] = 1

    # create a changegroup for all the branches we need to keep

    if backup == "all":

        _bundle(repo, [node], cl.heads(), node, 'backup')

    if saveheads or extranodes:

        chgrpfile = _bundle(repo, savebases.keys(), saveheads, node, 'temp',

                            extranodes)

    if saveheads or extranodes:

        ui.status("adding branch\n")

        f = open(chgrpfile, "rb")

        gen = changegroup.readbundle(f, chgrpfile)

        repo.addchangegroup(gen, 'strip', 'bundle:' + chgrpfile, True)

        f.close()

        if backup != "strip":

            os.unlink(chgrpfile)