/brz/remove-bazaar

# Copyright (C) 2009 Canonical Ltd

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""Tracker of refs."""

from __future__ import absolute_import

class RefTracker(object):

    def __init__(self):

        # Head tracking: last ref, last id per ref & map of commit ids to ref*s*

        self.last_ref = None

        self.last_ids = {}

        self.heads = {}

    def dump_stats(self, note):

        self._show_stats_for(self.last_ids, "last-ids", note=note)

        self._show_stats_for(self.heads, "heads", note=note)

    def clear(self):

        self.last_ids.clear()

        self.heads.clear()

    def track_heads(self, cmd):

        """Track the repository heads given a CommitCommand.

        :param cmd: the CommitCommand

        :return: the list of parents in terms of commit-ids

        """

        # Get the true set of parents

        if cmd.from_ is not None:

            parents = [cmd.from_]

        else:

            last_id = self.last_ids.get(cmd.ref)

            if last_id is not None:

                parents = [last_id]

            else:

                parents = []

        parents.extend(cmd.merges)

        # Track the heads

        self.track_heads_for_ref(cmd.ref, cmd.id, parents)

        return parents

    def track_heads_for_ref(self, cmd_ref, cmd_id, parents=None):

        if parents is not None:

            for parent in parents:

                if parent in self.heads:

                    del self.heads[parent]

        self.heads.setdefault(cmd_id, set()).add(cmd_ref)

        self.last_ids[cmd_ref] = cmd_id

        self.last_ref = cmd_ref