~bzr-pqm/bzr/bzr.dev : contents of bzrlib/memorytree.py at revision 5395

~bzr-pqm/bzr/bzr.dev : (revision 5395)

# Copyright (C) 2006 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""MemoryTree object.

See MemoryTree for more details.
"""


import os

from bzrlib import (
    errors,
    mutabletree,
    revision as _mod_revision,
    )
from bzrlib.decorators import needs_read_lock
from bzrlib.osutils import sha_file
from bzrlib.mutabletree import needs_tree_write_lock
from bzrlib.transport.memory import MemoryTransport


class MemoryTree(mutabletree.MutableTree):
    """A MemoryTree is a specialisation of MutableTree.

    It maintains nearly no state outside of read_lock and write_lock
    transactions. (it keeps a reference to the branch, and its last-revision
    only).
    """

    def __init__(self, branch, revision_id):
        """Construct a MemoryTree for branch using revision_id."""
        self.branch = branch
        self.bzrdir = branch.bzrdir
        self._branch_revision_id = revision_id
        self._locks = 0
        self._lock_mode = None

    @needs_tree_write_lock
    def _add(self, files, ids, kinds):
        """See MutableTree._add."""
        for f, file_id, kind in zip(files, ids, kinds):
            if kind is None:
                kind = 'file'
            if file_id is None:
                self._inventory.add_path(f, kind=kind)
            else:
                self._inventory.add_path(f, kind=kind, file_id=file_id)

    def basis_tree(self):
        """See Tree.basis_tree()."""
        return self._basis_tree

    @staticmethod
    def create_on_branch(branch):
        """Create a MemoryTree for branch, using the last-revision of branch."""
        revision_id = _mod_revision.ensure_null(branch.last_revision())
        return MemoryTree(branch, revision_id)

    def _gather_kinds(self, files, kinds):
        """See MutableTree._gather_kinds.

        This implementation does not care about the file kind of
        missing files, so is a no-op.
        """

    def get_file(self, file_id, path=None):
        """See Tree.get_file."""
        if path is None:
            path = self.id2path(file_id)
        return self._file_transport.get(path)

    def get_file_sha1(self, file_id, path=None, stat_value=None):
        """See Tree.get_file_sha1()."""
        if path is None:
            path = self.id2path(file_id)
        stream = self._file_transport.get(path)
        return sha_file(stream)

    def get_root_id(self):
        return self.path2id('')

    def _comparison_data(self, entry, path):
        """See Tree._comparison_data."""
        if entry is None:
            return None, False, None
        return entry.kind, entry.executable, None

    @needs_tree_write_lock
    def rename_one(self, from_rel, to_rel):
        file_id = self.path2id(from_rel)
        to_dir, to_tail = os.path.split(to_rel)
        to_parent_id = self.path2id(to_dir)
        self._file_transport.move(from_rel, to_rel)
        self._inventory.rename(file_id, to_parent_id, to_tail)

    def path_content_summary(self, path):
        """See Tree.path_content_summary."""
        id = self.path2id(path)
        if id is None:
            return 'missing', None, None, None
        kind = self.kind(id)
        if kind == 'file':
            bytes = self._file_transport.get_bytes(path)
            size = len(bytes)
            executable = self._inventory[id].executable
            sha1 = None # no stat cache
            return (kind, size, executable, sha1)
        elif kind == 'directory':
            # memory tree does not support nested trees yet.
            return kind, None, None, None
        elif kind == 'symlink':
            raise NotImplementedError('symlink support')
        else:
            raise NotImplementedError('unknown kind')

    def _file_size(self, entry, stat_value):
        """See Tree._file_size."""
        if entry is None:
            return 0
        return entry.text_size

    @needs_read_lock
    def get_parent_ids(self):
        """See Tree.get_parent_ids.

        This implementation returns the current cached value from
            self._parent_ids.
        """
        return list(self._parent_ids)

    def has_filename(self, filename):
        """See Tree.has_filename()."""
        return self._file_transport.has(filename)

    def is_executable(self, file_id, path=None):
        return self._inventory[file_id].executable

    def kind(self, file_id):
        return self._inventory[file_id].kind

    def mkdir(self, path, file_id=None):
        """See MutableTree.mkdir()."""
        self.add(path, file_id, 'directory')
        if file_id is None:
            file_id = self.path2id(path)
        self._file_transport.mkdir(path)
        return file_id

    @needs_read_lock
    def last_revision(self):
        """See MutableTree.last_revision."""
        return self._branch_revision_id

    def lock_read(self):
        """Lock the memory tree for reading.

        This triggers population of data from the branch for its revision.
        """
        self._locks += 1
        try:
            if self._locks == 1:
                self.branch.lock_read()
                self._lock_mode = "r"
                self._populate_from_branch()
        except:
            self._locks -= 1
            raise

    def lock_tree_write(self):
        """See MutableTree.lock_tree_write()."""
        self._locks += 1
        try:
            if self._locks == 1:
                self.branch.lock_read()
                self._lock_mode = "w"
                self._populate_from_branch()
            elif self._lock_mode == "r":
                raise errors.ReadOnlyError(self)
        except:
            self._locks -= 1
            raise

    def lock_write(self):
        """See MutableTree.lock_write()."""
        self._locks += 1
        try:
            if self._locks == 1:
                self.branch.lock_write()
                self._lock_mode = "w"
                self._populate_from_branch()
            elif self._lock_mode == "r":
                raise errors.ReadOnlyError(self)
        except:
            self._locks -= 1
            raise

    def _populate_from_branch(self):
        """Populate the in-tree state from the branch."""
        self._set_basis()
        if self._branch_revision_id == _mod_revision.NULL_REVISION:
            self._parent_ids = []
        else:
            self._parent_ids = [self._branch_revision_id]
        self._inventory = self._basis_tree._inventory._get_mutable_inventory()
        self._file_transport = MemoryTransport()
        # TODO copy the revision trees content, or do it lazy, or something.
        inventory_entries = self._inventory.iter_entries()
        for path, entry in inventory_entries:
            if path == '':
                continue
            if entry.kind == 'directory':
                self._file_transport.mkdir(path)
            elif entry.kind == 'file':
                self._file_transport.put_file(path,
                    self._basis_tree.get_file(entry.file_id))
            else:
                raise NotImplementedError(self._populate_from_branch)

    def put_file_bytes_non_atomic(self, file_id, bytes):
        """See MutableTree.put_file_bytes_non_atomic."""
        self._file_transport.put_bytes(self.id2path(file_id), bytes)

    def unlock(self):
        """Release a lock.

        This frees all cached state when the last lock context for the tree is
        left.
        """
        if self._locks == 1:
            self._basis_tree = None
            self._parent_ids = []
            self._inventory = None
            try:
                self.branch.unlock()
            finally:
                self._locks = 0
                self._lock_mode = None
        else:
            self._locks -= 1

    @needs_tree_write_lock
    def unversion(self, file_ids):
        """Remove the file ids in file_ids from the current versioned set.

        When a file_id is unversioned, all of its children are automatically
        unversioned.

        :param file_ids: The file ids to stop versioning.
        :raises: NoSuchId if any fileid is not currently versioned.
        """
        # XXX: This should be in mutabletree, but the inventory-save action
        # is not relevant to memory tree. Until that is done in unlock by
        # working tree, we cannot share the implementation.
        for file_id in file_ids:
            if self._inventory.has_id(file_id):
                self._inventory.remove_recursive_id(file_id)
            else:
                raise errors.NoSuchId(self, file_id)

    def set_parent_ids(self, revision_ids, allow_leftmost_as_ghost=False):
        """See MutableTree.set_parent_trees()."""
        for revision_id in revision_ids:
            _mod_revision.check_not_reserved_id(revision_id)
        if len(revision_ids) == 0:
            self._parent_ids = []
            self._branch_revision_id = _mod_revision.NULL_REVISION
        else:
            self._parent_ids = revision_ids
            self._branch_revision_id = revision_ids[0]
        self._allow_leftmost_as_ghost = allow_leftmost_as_ghost
        self._set_basis()
    
    def _set_basis(self):
        try:
            self._basis_tree = self.branch.repository.revision_tree(
                self._branch_revision_id)
        except errors.NoSuchRevision:
            if self._allow_leftmost_as_ghost:
                self._basis_tree = self.branch.repository.revision_tree(
                    _mod_revision.NULL_REVISION)
            else:
                raise

    def set_parent_trees(self, parents_list, allow_leftmost_as_ghost=False):
        """See MutableTree.set_parent_trees()."""
        if len(parents_list) == 0:
            self._parent_ids = []
            self._basis_tree = self.branch.repository.revision_tree(
                                   _mod_revision.NULL_REVISION)
        else:
            if parents_list[0][1] is None and not allow_leftmost_as_ghost:
                # a ghost in the left most parent
                raise errors.GhostRevisionUnusableHere(parents_list[0][0])
            self._parent_ids = [parent_id for parent_id, tree in parents_list]
            if parents_list[0][1] is None or parents_list[0][1] == 'null:':
                self._basis_tree = self.branch.repository.revision_tree(
                                       _mod_revision.NULL_REVISION)
            else:
                self._basis_tree = parents_list[0][1]
            self._branch_revision_id = parents_list[0][0]

1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	1	# Copyright (C) 2006 Canonical Ltd
	2	#
	3	# This program is free software; you can redistribute it and/or modify
	4	# it under the terms of the GNU General Public License as published by
	5	# the Free Software Foundation; either version 2 of the License, or
	6	# (at your option) any later version.
	7	#
	8	# This program is distributed in the hope that it will be useful,
	9	# but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	11	# GNU General Public License for more details.
	12	#
	13	# You should have received a copy of the GNU General Public License
	14	# along with this program; if not, write to the Free Software
4183.7.1 by Sabin Iacob update FSF mailing address	15	# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	16
	17	"""MemoryTree object.
	18
	19	See MemoryTree for more details.
	20	"""
	21
	22
3567.5.1 by John Arbash Meinel Implement rename_one on MemoryTree, and expose that in the Branch Builder	23	import os
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	24
2598.5.1 by Aaron Bentley Start eliminating the use of None to indicate null revision	25	from bzrlib import (
	26	errors,
	27	mutabletree,
	28	revision as _mod_revision,
	29	)
5121.2.4 by Jelmer Vernooij Remove more unused imports.	30	from bzrlib.decorators import needs_read_lock
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	31	from bzrlib.osutils import sha_file
1986.1.8 by Robert Collins Update to bzr.dev, which involves adding lock_tree_write to MutableTree and MemoryTree.	32	from bzrlib.mutabletree import needs_tree_write_lock
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	33	from bzrlib.transport.memory import MemoryTransport
	34
	35
	36	class MemoryTree(mutabletree.MutableTree):
	37	"""A MemoryTree is a specialisation of MutableTree.
3943.8.1 by Marius Kruger remove all trailing whitespace from bzr source	38
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	39	It maintains nearly no state outside of read_lock and write_lock
	40	transactions. (it keeps a reference to the branch, and its last-revision
	41	only).
	42	"""
	43
	44	def __init__(self, branch, revision_id):
	45	"""Construct a MemoryTree for branch using revision_id."""
	46	self.branch = branch
	47	self.bzrdir = branch.bzrdir
	48	self._branch_revision_id = revision_id
	49	self._locks = 0
	50	self._lock_mode = None
	51
1986.1.8 by Robert Collins Update to bzr.dev, which involves adding lock_tree_write to MutableTree and MemoryTree.	52	@needs_tree_write_lock
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	53	def _add(self, files, ids, kinds):
	54	"""See MutableTree._add."""
	55	for f, file_id, kind in zip(files, ids, kinds):
	56	if kind is None:
	57	kind = 'file'
	58	if file_id is None:
	59	self._inventory.add_path(f, kind=kind)
	60	else:
	61	self._inventory.add_path(f, kind=kind, file_id=file_id)
	62
	63	def basis_tree(self):
	64	"""See Tree.basis_tree()."""
	65	return self._basis_tree
	66
	67	@staticmethod
	68	def create_on_branch(branch):
	69	"""Create a MemoryTree for branch, using the last-revision of branch."""
2598.5.4 by Aaron Bentley Restore original Branch.last_revision behavior, fix bits that care	70	revision_id = _mod_revision.ensure_null(branch.last_revision())
2598.5.1 by Aaron Bentley Start eliminating the use of None to indicate null revision	71	return MemoryTree(branch, revision_id)
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	72
	73	def _gather_kinds(self, files, kinds):
	74	"""See MutableTree._gather_kinds.
3943.8.1 by Marius Kruger remove all trailing whitespace from bzr source	75
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	76	This implementation does not care about the file kind of
	77	missing files, so is a no-op.
	78	"""
	79
2743.3.3 by Ian Clatworthy Skip path lookup for tree.get_file() when we already know the path	80	def get_file(self, file_id, path=None):
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	81	"""See Tree.get_file."""
2743.3.3 by Ian Clatworthy Skip path lookup for tree.get_file() when we already know the path	82	if path is None:
	83	path = self.id2path(file_id)
	84	return self._file_transport.get(path)
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	85
2564.2.1 by Ian Clatworthy refactor commit to support alternative population meothds	86	def get_file_sha1(self, file_id, path=None, stat_value=None):
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	87	"""See Tree.get_file_sha1()."""
	88	if path is None:
	89	path = self.id2path(file_id)
	90	stream = self._file_transport.get(path)
	91	return sha_file(stream)
	92
2946.3.5 by John Arbash Meinel MemoryTree is not tested under the tree_implementations tests.	93	def get_root_id(self):
	94	return self.path2id('')
	95
2564.2.1 by Ian Clatworthy refactor commit to support alternative population meothds	96	def _comparison_data(self, entry, path):
	97	"""See Tree._comparison_data."""
	98	if entry is None:
	99	return None, False, None
	100	return entry.kind, entry.executable, None
	101
3567.5.1 by John Arbash Meinel Implement rename_one on MemoryTree, and expose that in the Branch Builder	102	@needs_tree_write_lock
	103	def rename_one(self, from_rel, to_rel):
	104	file_id = self.path2id(from_rel)
	105	to_dir, to_tail = os.path.split(to_rel)
3514.4.44 by John Arbash Meinel Revert the path2id fix, because to_dir can be anywhere, not just	106	to_parent_id = self.path2id(to_dir)
3567.5.1 by John Arbash Meinel Implement rename_one on MemoryTree, and expose that in the Branch Builder	107	self._file_transport.move(from_rel, to_rel)
	108	self._inventory.rename(file_id, to_parent_id, to_tail)
3514.4.38 by John Arbash Meinel Use direct access to the inventory instead of path2id.	109
2776.4.2 by Robert Collins nuke _read_tree_state and snapshot from inventory, moving responsibility into the commit builder.	110	def path_content_summary(self, path):
	111	"""See Tree.path_content_summary."""
	112	id = self.path2id(path)
	113	if id is None:
	114	return 'missing', None, None, None
	115	kind = self.kind(id)
	116	if kind == 'file':
	117	bytes = self._file_transport.get_bytes(path)
	118	size = len(bytes)
	119	executable = self._inventory[id].executable
	120	sha1 = None # no stat cache
	121	return (kind, size, executable, sha1)
	122	elif kind == 'directory':
	123	# memory tree does not support nested trees yet.
	124	return kind, None, None, None
	125	elif kind == 'symlink':
	126	raise NotImplementedError('symlink support')
	127	else:
	128	raise NotImplementedError('unknown kind')
	129
2564.2.1 by Ian Clatworthy refactor commit to support alternative population meothds	130	def _file_size(self, entry, stat_value):
	131	"""See Tree._file_size."""
	132	if entry is None:
	133	return 0
	134	return entry.text_size
	135
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	136	@needs_read_lock
	137	def get_parent_ids(self):
	138	"""See Tree.get_parent_ids.
	139
	140	This implementation returns the current cached value from
	141	self._parent_ids.
	142	"""
	143	return list(self._parent_ids)
	144
	145	def has_filename(self, filename):
	146	"""See Tree.has_filename()."""
	147	return self._file_transport.has(filename)
	148
	149	def is_executable(self, file_id, path=None):
	150	return self._inventory[file_id].executable
	151
1959.4.2 by Aaron Bentley Merge bzr.dev	152	def kind(self, file_id):
	153	return self._inventory[file_id].kind
	154
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	155	def mkdir(self, path, file_id=None):
	156	"""See MutableTree.mkdir()."""
	157	self.add(path, file_id, 'directory')
	158	if file_id is None:
	159	file_id = self.path2id(path)
	160	self._file_transport.mkdir(path)
	161	return file_id
	162
1986.1.6 by Robert Collins Add MemoryTree.last_revision.	163	@needs_read_lock
	164	def last_revision(self):
	165	"""See MutableTree.last_revision."""
	166	return self._branch_revision_id
	167
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	168	def lock_read(self):
	169	"""Lock the memory tree for reading.
	170
	171	This triggers population of data from the branch for its revision.
	172	"""
	173	self._locks += 1
	174	try:
	175	if self._locks == 1:
	176	self.branch.lock_read()
	177	self._lock_mode = "r"
	178	self._populate_from_branch()
	179	except:
	180	self._locks -= 1
	181	raise
	182
1986.1.8 by Robert Collins Update to bzr.dev, which involves adding lock_tree_write to MutableTree and MemoryTree.	183	def lock_tree_write(self):
	184	"""See MutableTree.lock_tree_write()."""
	185	self._locks += 1
	186	try:
	187	if self._locks == 1:
	188	self.branch.lock_read()
	189	self._lock_mode = "w"
	190	self._populate_from_branch()
	191	elif self._lock_mode == "r":
	192	raise errors.ReadOnlyError(self)
	193	except:
	194	self._locks -= 1
	195	raise
	196
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	197	def lock_write(self):
	198	"""See MutableTree.lock_write()."""
	199	self._locks += 1
	200	try:
	201	if self._locks == 1:
	202	self.branch.lock_write()
	203	self._lock_mode = "w"
	204	self._populate_from_branch()
	205	elif self._lock_mode == "r":
	206	raise errors.ReadOnlyError(self)
	207	except:
	208	self._locks -= 1
	209	raise
	210
	211	def _populate_from_branch(self):
	212	"""Populate the in-tree state from the branch."""
4190.1.4 by Robert Collins Cache ghosts when we can get them from a RemoteRepository in get_parent_map.	213	self._set_basis()
3668.5.4 by Jelmer Vernooij Eliminate more uses of Repository.revision_tree(None).	214	if self._branch_revision_id == _mod_revision.NULL_REVISION:
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	215	self._parent_ids = []
	216	else:
	217	self._parent_ids = [self._branch_revision_id]
4244.2.1 by Vincent Ladeuil inv._get_mutable_inventory() - prepare for CHKInventory	218	self._inventory = self._basis_tree._inventory._get_mutable_inventory()
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	219	self._file_transport = MemoryTransport()
	220	# TODO copy the revision trees content, or do it lazy, or something.
	221	inventory_entries = self._inventory.iter_entries()
	222	for path, entry in inventory_entries:
1731.1.50 by Aaron Bentley Merge bzr.dev	223	if path == '':
1731.1.50 by Aaron Bentley Merge bzr.dev	224	continue
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	225	if entry.kind == 'directory':
	226	self._file_transport.mkdir(path)
	227	elif entry.kind == 'file':
1986.1.4 by Robert Collins Fixup deprecations from bzr.dev.	228	self._file_transport.put_file(path,
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	229	self._basis_tree.get_file(entry.file_id))
	230	else:
	231	raise NotImplementedError(self._populate_from_branch)
	232
	233	def put_file_bytes_non_atomic(self, file_id, bytes):
	234	"""See MutableTree.put_file_bytes_non_atomic."""
1986.1.4 by Robert Collins Fixup deprecations from bzr.dev.	235	self._file_transport.put_bytes(self.id2path(file_id), bytes)
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	236
	237	def unlock(self):
	238	"""Release a lock.
	239
	240	This frees all cached state when the last lock context for the tree is
	241	left.
	242	"""
	243	if self._locks == 1:
	244	self._basis_tree = None
	245	self._parent_ids = []
	246	self._inventory = None
	247	try:
	248	self.branch.unlock()
	249	finally:
	250	self._locks = 0
	251	self._lock_mode = None
	252	else:
	253	self._locks -= 1
	254
1986.1.8 by Robert Collins Update to bzr.dev, which involves adding lock_tree_write to MutableTree and MemoryTree.	255	@needs_tree_write_lock
1986.1.3 by Robert Collins Merge bzr.dev.	256	def unversion(self, file_ids):
	257	"""Remove the file ids in file_ids from the current versioned set.
	258
	259	When a file_id is unversioned, all of its children are automatically
	260	unversioned.
	261
	262	:param file_ids: The file ids to stop versioning.
	263	:raises: NoSuchId if any fileid is not currently versioned.
	264	"""
	265	# XXX: This should be in mutabletree, but the inventory-save action
	266	# is not relevant to memory tree. Until that is done in unlock by
	267	# working tree, we cannot share the implementation.
	268	for file_id in file_ids:
	269	if self._inventory.has_id(file_id):
	270	self._inventory.remove_recursive_id(file_id)
	271	else:
	272	raise errors.NoSuchId(self, file_id)
	273
2418.5.1 by John Arbash Meinel Make a Branch helper which can create a very basic MemoryTree with history.	274	def set_parent_ids(self, revision_ids, allow_leftmost_as_ghost=False):
	275	"""See MutableTree.set_parent_trees()."""
2598.5.2 by Aaron Bentley Got all tests passing with Branch returning 'null:' for null revision	276	for revision_id in revision_ids:
	277	_mod_revision.check_not_reserved_id(revision_id)
2418.5.1 by John Arbash Meinel Make a Branch helper which can create a very basic MemoryTree with history.	278	if len(revision_ids) == 0:
	279	self._parent_ids = []
4190.1.4 by Robert Collins Cache ghosts when we can get them from a RemoteRepository in get_parent_map.	280	self._branch_revision_id = _mod_revision.NULL_REVISION
2418.5.1 by John Arbash Meinel Make a Branch helper which can create a very basic MemoryTree with history.	281	else:
	282	self._parent_ids = revision_ids
	283	self._branch_revision_id = revision_ids[0]
4190.1.4 by Robert Collins Cache ghosts when we can get them from a RemoteRepository in get_parent_map.	284	self._allow_leftmost_as_ghost = allow_leftmost_as_ghost
	285	self._set_basis()
	286
	287	def _set_basis(self):
	288	try:
	289	self._basis_tree = self.branch.repository.revision_tree(
	290	self._branch_revision_id)
	291	except errors.NoSuchRevision:
	292	if self._allow_leftmost_as_ghost:
	293	self._basis_tree = self.branch.repository.revision_tree(
	294	_mod_revision.NULL_REVISION)
	295	else:
	296	raise
2418.5.1 by John Arbash Meinel Make a Branch helper which can create a very basic MemoryTree with history.	297
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	298	def set_parent_trees(self, parents_list, allow_leftmost_as_ghost=False):
	299	"""See MutableTree.set_parent_trees()."""
	300	if len(parents_list) == 0:
	301	self._parent_ids = []
3668.5.1 by Jelmer Vernooij Use NULL_REVISION rather than None for Repository.revision_tree().	302	self._basis_tree = self.branch.repository.revision_tree(
	303	_mod_revision.NULL_REVISION)
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	304	else:
	305	if parents_list[0][1] is None and not allow_leftmost_as_ghost:
	306	# a ghost in the left most parent
	307	raise errors.GhostRevisionUnusableHere(parents_list[0][0])
	308	self._parent_ids = [parent_id for parent_id, tree in parents_list]
2598.5.2 by Aaron Bentley Got all tests passing with Branch returning 'null:' for null revision	309	if parents_list[0][1] is None or parents_list[0][1] == 'null:':
3668.5.1 by Jelmer Vernooij Use NULL_REVISION rather than None for Repository.revision_tree().	310	self._basis_tree = self.branch.repository.revision_tree(
	311	_mod_revision.NULL_REVISION)
1986.1.2 by Robert Collins Various changes to allow non-workingtree specific tests to run entirely	312	else:
	313	self._basis_tree = parents_list[0][1]
1986.1.6 by Robert Collins Add MemoryTree.last_revision.	314	self._branch_revision_id = parents_list[0][0]