~bzr-pqm/bzr/bzr.dev : contents of bzrlib/identitymap.py at revision 2325.2.5

~bzr-pqm/bzr/bzr.dev : (revision 2325.2.5)

# Copyright (C) 2005 Canonical Ltd
#   Authors: Robert Collins <robert.collins@canonical.com>
#
# 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

"""This module provides an IdentityMap."""


from bzrlib import (
    errors,
    osutils,
    )


class IdentityMap(object):
    """An in memory map from object id to instance.
    
    An IdentityMap maps from keys to single instances of objects in memory.
    We have explicit calls on the map for the root of each inheritance tree
    that is store in the map. Look for find_CLASS and add_CLASS methods.
    """

    def add_revision_history(self, revision_history):
        """Add a revision_history object to the map.

        There can only be one!
        """
        if self._revision_history is not None:
            raise errors.BzrError("A revision history (%s) is already "
                                  "identity map" % self._revision_history)
        self._revision_history = revision_history

    def add_weave(self, id, weave):
        """Add weave to the map with a given id."""
        if self._weave_key(id) in self._map:
            raise errors.BzrError('weave %s already in the identity map' % id)
        self._map[self._weave_key(id)] = weave
        self._reverse_map[weave] = self._weave_key(id)

    def find_revision_history(self):
        return self._revision_history

    def find_weave(self, id):
        """Return the weave for 'id', or None if it is not present."""
        return self._map.get(self._weave_key(id), None)

    def __init__(self):
        super(IdentityMap, self).__init__()
        self._map = {}
        self._reverse_map = {}
        self._revision_history = None

    def remove_object(self, an_object):
        """Remove object from map."""
        if isinstance(an_object, list):
            if self._revision_history is an_object:
                self._revision_history = None
            else:
                raise KeyError('%r not in identity map' % an_object)
        else:
            self._map.pop(self._reverse_map[an_object])
            self._reverse_map.pop(an_object)

    def _weave_key(self, id):
        """Return the key for a weaves id."""
        return "weave-" + id

        
class NullIdentityMap(object):
    """A pretend in memory map from object id to instance.
    
    A NullIdentityMap is an Identity map that does not store anything in it.
    """

    def add_weave(self, id, weave):
        """See IdentityMap.add_weave."""

    def add_revision_history(self, revision_history):
        """See IdentityMap.add_revision_history."""

    def find_weave(self, id):
        """See IdentityMap.find_weave."""
        return None

    def find_revision_history(self):
        """See IdentityMap.find_revision_history."""

2052.3.2 by John Arbash Meinel Change Copyright .. by Canonical to Copyright ... Canonical	1	# Copyright (C) 2005 Canonical Ltd
1417.1.6 by Robert Collins introduce transactions for grouping actions done to and with branches	2	# Authors: Robert Collins <robert.collins@canonical.com>
	3	#
	4	# This program is free software; you can redistribute it and/or modify
	5	# it under the terms of the GNU General Public License as published by
	6	# the Free Software Foundation; either version 2 of the License, or
	7	# (at your option) any later version.
	8	#
	9	# This program is distributed in the hope that it will be useful,
	10	# but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	# GNU General Public License for more details.
	13	#
	14	# You should have received a copy of the GNU General Public License
	15	# along with this program; if not, write to the Free Software
	16	# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	17
	18	"""This module provides an IdentityMap."""
	19
	20
2294.1.10 by John Arbash Meinel Switch all apis over to utf8 file ids. All tests pass	21	from bzrlib import (
	22	errors,
	23	osutils,
	24	)
1417.1.6 by Robert Collins introduce transactions for grouping actions done to and with branches	25
	26
	27	class IdentityMap(object):
	28	"""An in memory map from object id to instance.
	29
	30	An IdentityMap maps from keys to single instances of objects in memory.
	31	We have explicit calls on the map for the root of each inheritance tree
	32	that is store in the map. Look for find_CLASS and add_CLASS methods.
	33	"""
	34
1417.1.12 by Robert Collins cache revision history during read transactions	35	def add_revision_history(self, revision_history):
	36	"""Add a revision_history object to the map.
	37
	38	There can only be one!
	39	"""
	40	if self._revision_history is not None:
	41	raise errors.BzrError("A revision history (%s) is already "
	42	"identity map" % self._revision_history)
	43	self._revision_history = revision_history
	44
1417.1.6 by Robert Collins introduce transactions for grouping actions done to and with branches	45	def add_weave(self, id, weave):
	46	"""Add weave to the map with a given id."""
	47	if self._weave_key(id) in self._map:
	48	raise errors.BzrError('weave %s already in the identity map' % id)
	49	self._map[self._weave_key(id)] = weave
1417.1.10 by Robert Collins add a cache bound to Transactions, and a precious facility, so that we keep inventory.weave in memory, but can discard weaves for other such files.	50	self._reverse_map[weave] = self._weave_key(id)
1417.1.6 by Robert Collins introduce transactions for grouping actions done to and with branches	51
1417.1.12 by Robert Collins cache revision history during read transactions	52	def find_revision_history(self):
	53	return self._revision_history
	54
1417.1.6 by Robert Collins introduce transactions for grouping actions done to and with branches	55	def find_weave(self, id):
	56	"""Return the weave for 'id', or None if it is not present."""
	57	return self._map.get(self._weave_key(id), None)
	58
	59	def __init__(self):
	60	super(IdentityMap, self).__init__()
	61	self._map = {}
1417.1.10 by Robert Collins add a cache bound to Transactions, and a precious facility, so that we keep inventory.weave in memory, but can discard weaves for other such files.	62	self._reverse_map = {}
1417.1.12 by Robert Collins cache revision history during read transactions	63	self._revision_history = None
1417.1.10 by Robert Collins add a cache bound to Transactions, and a precious facility, so that we keep inventory.weave in memory, but can discard weaves for other such files.	64
	65	def remove_object(self, an_object):
1417.1.12 by Robert Collins cache revision history during read transactions	66	"""Remove object from map."""
	67	if isinstance(an_object, list):
	68	if self._revision_history is an_object:
	69	self._revision_history = None
	70	else:
	71	raise KeyError('%r not in identity map' % an_object)
	72	else:
1417.1.10 by Robert Collins add a cache bound to Transactions, and a precious facility, so that we keep inventory.weave in memory, but can discard weaves for other such files.	73	self._map.pop(self._reverse_map[an_object])
	74	self._reverse_map.pop(an_object)
1417.1.6 by Robert Collins introduce transactions for grouping actions done to and with branches	75
	76	def _weave_key(self, id):
	77	"""Return the key for a weaves id."""
	78	return "weave-" + id
	79
	80
	81	class NullIdentityMap(object):
	82	"""A pretend in memory map from object id to instance.
	83
	84	A NullIdentityMap is an Identity map that does not store anything in it.
	85	"""
	86
	87	def add_weave(self, id, weave):
	88	"""See IdentityMap.add_weave."""
	89
1417.1.12 by Robert Collins cache revision history during read transactions	90	def add_revision_history(self, revision_history):
	91	"""See IdentityMap.add_revision_history."""
	92
1417.1.6 by Robert Collins introduce transactions for grouping actions done to and with branches	93	def find_weave(self, id):
	94	"""See IdentityMap.find_weave."""
	95	return None
	96
1417.1.12 by Robert Collins cache revision history during read transactions	97	def find_revision_history(self):
	98	"""See IdentityMap.find_revision_history."""