/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, write to the Free Software

# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

"""A manager of caches."""

from bzrlib import lru_cache

class CacheManager(object):

    def __init__(self, info, verbose=False, inventory_cache_size=10):

        """Create a manager of caches.

        :param info: a ConfigObj holding the output from

            the --info processor, or None if no hints are available

        """

        self.verbose = verbose

        # dataref -> data. datref is either :mark or the sha-1.

        # Sticky blobs aren't removed after being referenced.

        self._blobs = {}

        self._sticky_blobs = {}

        # revision-id -> Inventory cache

        # these are large and we probably don't need too many as

        # most parents are recent in history

        self.inventories = lru_cache.LRUCache(inventory_cache_size)

        # import commmit-ids -> revision-id lookup table

        # we need to keep all of these but they are small

        self.revision_ids = {}

        # path -> file-ids - as generated

        self.file_ids = {}

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

        self.last_ref = None

        self.last_ids = {}

        self.heads = {}

        # Work out the blobs to make sticky - None means all

        self._blobs_to_keep = None

        if info is not None:

            try:

                self._blobs_to_keep = info['Blob usage tracking']['multi']

            except KeyError:

                # info not in file - possible when no blobs used

                pass

    def store_blob(self, id, data):

        """Store a blob of data."""

        if (self._blobs_to_keep is None or data == '' or

            id in self._blobs_to_keep):

            self._sticky_blobs[id] = data

        else:

            self._blobs[id] = data

    def fetch_blob(self, id):

        """Fetch a blob of data."""

        try:

            return self._sticky_blobs[id]

        except KeyError:

            return self._blobs.pop(id)

    def delete_path(self, path):

        """Remove a path from caches."""

        # we actually want to remember what file-id we gave a path,

        # even when that file is deleted, so doing nothing is correct

        pass

    def rename_path(self, old_path, new_path):

        """Rename a path in the caches."""

        # In this case, we need to forget the file-id we gave a path,

        # otherwise, we'll get duplicate file-ids in the repository.

        self.file_ids[new_path] = self.file_ids[old_path]

        del self.file_ids[old_path]

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

        if parents is not None:

            for parent in parents:

                refs = self.heads.get(parent)

                if refs:

                    refs.discard(cmd_ref)

                    if not refs:

                        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