/brz/remove-bazaar

# Copyright (C) 2005, 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

"""WorkingTree4 format and implementation.

WorkingTree4 provides the dirstate based working tree logic.

To get a WorkingTree, call bzrdir.open_workingtree() or

WorkingTree.open(dir).

"""

from cStringIO import StringIO

import os

from bzrlib.lazy_import import lazy_import

lazy_import(globals(), """

from bisect import bisect_left

import collections

from copy import deepcopy

import errno

import itertools

import operator

import stat

from time import time

import warnings

import bzrlib

from bzrlib import (

    bzrdir,

    conflicts as _mod_conflicts,

    dirstate,

    errors,

    generate_ids,

    globbing,

    hashcache,

    ignores,

    merge,

    osutils,

    textui,

    transform,

    urlutils,

    xml5,

    xml6,

    )

import bzrlib.branch

from bzrlib.transport import get_transport

import bzrlib.ui

""")

from bzrlib import symbol_versioning

from bzrlib.decorators import needs_read_lock, needs_write_lock

from bzrlib.inventory import InventoryEntry, Inventory, ROOT_ID, make_entry

from bzrlib.lockable_files import LockableFiles, TransportLock

from bzrlib.lockdir import LockDir

import bzrlib.mutabletree

from bzrlib.mutabletree import needs_tree_write_lock

from bzrlib.osutils import (

    compact_date,

    file_kind,

    isdir,

    normpath,

    pathjoin,

    rand_chars,

    realpath,

    safe_unicode,

    splitpath,

    supports_executable,

    )

from bzrlib.trace import mutter, note

from bzrlib.transport.local import LocalTransport

from bzrlib.progress import DummyProgress, ProgressPhase

from bzrlib.revision import NULL_REVISION, CURRENT_REVISION

from bzrlib.rio import RioReader, rio_file, Stanza

from bzrlib.symbol_versioning import (deprecated_passed,

        deprecated_method,

        deprecated_function,

        DEPRECATED_PARAMETER,

        zero_eight,

        zero_eleven,

        zero_thirteen,

        )

from bzrlib.tree import Tree

from bzrlib.workingtree import WorkingTree, WorkingTree3, WorkingTreeFormat3

class WorkingTree4(WorkingTree3):

    """This is the Format 4 working tree.

    This differs from WorkingTree3 by:

     - having a consolidated internal dirstate.

     - not having a regular inventory attribute.

    This is new in bzr TODO FIXME SETMEBEFORE MERGE.

    """

    def __init__(self, basedir,

                 branch,

                 _control_files=None,

                 _format=None,

                 _bzrdir=None):

        """Construct a WorkingTree for basedir.

        If the branch is not supplied, it is opened automatically.

        If the branch is supplied, it must be the branch for this basedir.

        (branch.base is not cross checked, because for remote branches that

        would be meaningless).

        """

        self._format = _format

        self.bzrdir = _bzrdir

        from bzrlib.hashcache import HashCache

        from bzrlib.trace import note, mutter

        assert isinstance(basedir, basestring), \

            "base directory %r is not a string" % basedir

        basedir = safe_unicode(basedir)

        mutter("opening working tree %r", basedir)

        self._branch = branch

        assert isinstance(self.branch, bzrlib.branch.Branch), \

            "branch %r is not a Branch" % self.branch

        self.basedir = realpath(basedir)

        # if branch is at our basedir and is a format 6 or less

        # assume all other formats have their own control files.

        assert isinstance(_control_files, LockableFiles), \

            "_control_files must be a LockableFiles, not %r" % _control_files

        self._control_files = _control_files

        # update the whole cache up front and write to disk if anything changed;

        # in the future we might want to do this more selectively

        # two possible ways offer themselves : in self._unlock, write the cache

        # if needed, or, when the cache sees a change, append it to the hash

        # cache file, and have the parser take the most recent entry for a

        # given path only.

        cache_filename = self.bzrdir.get_workingtree_transport(None).local_abspath('stat-cache')

        hc = self._hashcache = HashCache(basedir, cache_filename, self._control_files._file_mode)

        hc.read()

        # is this scan needed ? it makes things kinda slow.

        #hc.scan()

        if hc.needs_write:

            mutter("write hc")

            hc.write()

        self._dirty = None

        #-------------

        # during a read or write lock these objects are set, and are

        # None the rest of the time.

        self._dirstate = None

        self._inventory = None

        #-------------

    @needs_tree_write_lock

    def _add(self, files, ids, kinds):

        """See MutableTree._add."""

        state = self.current_dirstate()

        for f, file_id, kind in zip(files, ids, kinds):

            f = f.strip('/')

            assert '//' not in f

            assert '..' not in f

            if file_id is None:

                file_id = generate_ids.gen_file_id(f)

            # deliberately add the file with no cached stat or sha1

            # - on the first access it will be gathered, and we can

            # always change this once tests are all passing.

            state.add(f, file_id, kind, None, '')

        self._dirty = True

    def current_dirstate(self):

        """Return the current dirstate object. 

        This is not part of the tree interface and only exposed for ease of

        testing.

        :raises errors.NotWriteLocked: when not in a lock. 

            XXX: This should probably be errors.NotLocked.

        """

        if not self._control_files._lock_count:

            raise errors.ObjectNotLocked(self)

        if self._dirstate is not None:

            return self._dirstate

        local_path = self.bzrdir.get_workingtree_transport(None

            ).local_abspath('dirstate')

        self._dirstate = dirstate.DirState.on_file(local_path)

        return self._dirstate

    def flush(self):

        """Write all cached data to disk."""

        if self._control_files._lock_mode != 'w':

            raise errors.NotWriteLocked(self)

        self.current_dirstate().save()

        self._inventory = None

        self._dirty = False

    def _generate_inventory(self):

        """Create and set self.inventory from the dirstate object.

        This is relatively expensive: we have to walk the entire dirstate.

        Ideally we would not, and can deprecate this function.

        """

        dirstate = self.current_dirstate()

        rows = self._dirstate._iter_rows()

        root_row = rows.next()

        inv = Inventory(root_id=root_row[0][3].decode('utf8'))

        for line in rows:

            dirname, name, kind, fileid_utf8, size, stat, link_or_sha1 = line[0]

            if dirname == '/':

                # not in this revision tree.

                continue

            parent_id = inv[inv.path2id(dirname.decode('utf8'))].file_id

            file_id = fileid_utf8.decode('utf8')

            entry = make_entry(kind, name.decode('utf8'), parent_id, file_id)

            if kind == 'file':

                #entry.executable = executable

                #entry.text_size = size

                #entry.text_sha1 = sha1

                pass

            inv.add(entry)

        self._inventory = inv

    def get_file_sha1(self, file_id, path=None, stat_value=None):

        #if not path:

        #    path = self.inventory.id2path(file_id)

        #    # now lookup row by path

        row, parents = self._get_row(file_id=file_id)

        assert row is not None, 'what error should this raise'

        # TODO:

        # if row stat is valid, use cached sha1, else, get a new sha1.

        path = (row[0] + '/' + row[1]).strip('/').decode('utf8')

        return self._hashcache.get_sha1(path, stat_value)

    def _get_inventory(self):

        """Get the inventory for the tree. This is only valid within a lock."""

        if self._inventory is not None:

            return self._inventory

        self._generate_inventory()

        return self._inventory

    inventory = property(_get_inventory,

                         doc="Inventory of this Tree")

    @needs_read_lock

    def get_parent_ids(self):

        """See Tree.get_parent_ids.

        This implementation requests the ids list from the dirstate file.

        """

        return self.current_dirstate().get_parent_ids()

    @needs_read_lock

    def get_root_id(self):

        """Return the id of this trees root"""

        return self.current_dirstate()._iter_rows().next()[0][3].decode('utf8')

    def _get_block_row_index(self, dirname, basename):

        """Get the coordinates for a path in the state structure.

        :param dirname: The dirname to lookup.

        :param basename: The basename to lookup.

        :return: A tuple describing where the path is located, or should be

            inserted. The tuple contains four fields: the block index, the row

            index, anda two booleans are True when the directory is present, and

            when the entire path is present.  There is no guarantee that either

            coordinate is currently reachable unless the found field for it is

            True. For instance, a directory not present in the state may be

            returned with a value one greater than the current highest block

            offset. The directory present field will always be True when the

            path present field is True.

        """

        assert not (dirname == '' and basename == ''), 'blackhole lookup error'

        state = self.current_dirstate()

        state._read_dirblocks_if_needed()

        block_index = bisect_left(state._dirblocks, (dirname, []))

        if (block_index == len(state._dirblocks) or

            state._dirblocks[block_index][0] != dirname):

            # no such directory - return the dir index and 0 for the row.

            return block_index, 0, False, False

        block = state._dirblocks[block_index][1] # access the rows only

        search = ((dirname, basename), [])

        row_index = bisect_left(block, search)

        if row_index == len(block) or block[row_index][0][1] != basename:

            return block_index, row_index, True, False

        return block_index, row_index, True, True

    def _get_row(self, file_id=None, path=None):

        """Get the dirstate row for file_id or path.

        If either file_id or path is supplied, it is used as the key to lookup.

        If both are supplied, the fastest lookup is used, and an error is

        raised if they do not both point at the same row.

        :param file_id: An optional unicode file_id to be looked up.

        :param path: An optional unicode path to be looked up.

        :return: The dirstate row tuple for path/file_id, or (None, None)

        """

        if file_id is None and path is None:

            raise errors.BzrError('must supply file_id or path')

        state = self.current_dirstate()

        state._read_dirblocks_if_needed()

        if file_id is not None:

            fileid_utf8 = file_id.encode('utf8')

        if path is not None:

            # path lookups are faster

            row = state._get_row(path)

            if file_id:

                if row[0][3] != fileid_utf8:

                    raise BzrError('integrity error ? : mismatching file_id and path')

            return row

        else:

            for row in state._iter_rows():

                if row[0][3] == fileid_utf8:

                    return row

            return None, None

    def has_id(self, file_id):

        state = self.current_dirstate()

        fileid_utf8 = file_id.encode('utf8')

        row, parents = self._get_row(file_id)

        if row is None:

            return False

        return osutils.lexists(pathjoin(

                    self.basedir, row[0].decode('utf8'), row[1].decode('utf8')))

    @needs_read_lock

    def id2path(self, fileid):

        state = self.current_dirstate()

        fileid_utf8 = fileid.encode('utf8')

        for row, parents in state._iter_rows():

            if row[3] == fileid_utf8:

                return (row[0] + '/' + row[1]).decode('utf8').strip('/')

    @needs_read_lock

    def __iter__(self):

        """Iterate through file_ids for this tree.

        file_ids are in a WorkingTree if they are in the working inventory

        and the working file exists.

        """

        result = []

        for row, parents in self.current_dirstate()._iter_rows():

            if row[0] == '/':

                continue

            path = pathjoin(self.basedir, row[0].decode('utf8'), row[1].decode('utf8'))

            if osutils.lexists(path):

                result.append(row[3].decode('utf8'))

        return iter(result)

    @needs_read_lock

    def _last_revision(self):

        """See Mutable.last_revision."""

        parent_ids = self.current_dirstate().get_parent_ids()

        if parent_ids:

            return parent_ids[0].decode('utf8')

        else:

            return None

    @needs_tree_write_lock

    def move(self, from_paths, to_dir=None, after=False, **kwargs):

        """See WorkingTree.move()."""

        if not from_paths:

            return ()

        state = self.current_dirstate()

        # check for deprecated use of signature

        if to_dir is None:

            to_dir = kwargs.get('to_name', None)

            if to_dir is None:

                raise TypeError('You must supply a target directory')

            else:

                symbol_versioning.warn('The parameter to_name was deprecated'

                                       ' in version 0.13. Use to_dir instead',

                                       DeprecationWarning)

        assert not isinstance(from_paths, basestring)

        to_dir_utf8 = to_dir.encode('utf8')

        to_row_dirname, to_basename = os.path.split(to_dir_utf8)

        # check destination directory

        # get the details for it

        to_row_block_index, to_row_row_index, dir_present, row_present = \

            self._get_block_row_index(to_row_dirname, to_basename)

        if not row_present:

            raise errors.BzrMoveFailedError('', to_dir,

                errors.NotInWorkingDirectory(to_dir))

        to_row = state._dirblocks[to_row_block_index][1][to_row_row_index][0]

        # get a handle on the block itself.

        to_block_index = state._ensure_block(

            to_row_block_index, to_row_row_index, to_dir_utf8)

        to_block = state._dirblocks[to_block_index]

        to_abs = self.abspath(to_dir)

        if not isdir(to_abs):

            raise errors.BzrMoveFailedError('',to_dir,

                errors.NotADirectory(to_abs))

        if to_row[2] != 'directory':

            raise errors.BzrMoveFailedError('',to_dir,

                errors.NotADirectory(to_abs))

        if self._inventory is not None:

            update_inventory = True

            inv = self.inventory

            to_dir_ie = inv[to_dir_id]

            to_dir_id = to_row[3].decode('utf8')

        else:

            update_inventory = False

        # create rename entries and tuples

        for from_rel in from_paths:

            # from_rel is 'pathinroot/foo/bar'

            from_dirname, from_tail = os.path.split(from_rel)

            from_dirname = from_dirname.encode('utf8')

            from_row = self._get_row(path=from_rel)

            if from_row == (None, None):

                raise errors.BzrMoveFailedError(from_rel,to_dir,

                    errors.NotVersionedError(path=str(from_rel)))

            from_id = from_row[0][3].decode('utf8')

            to_rel = pathjoin(to_dir, from_tail)

            item_to_row = self._get_row(path=to_rel)

            if item_to_row != (None, None):

                raise errors.BzrMoveFailedError(from_rel, to_rel,

                    "Target is already versioned.")

            if from_rel == to_rel:

                raise errors.BzrMoveFailedError(from_rel, to_rel,

                    "Source and target are identical.")

            from_missing = not self.has_filename(from_rel)

            to_missing = not self.has_filename(to_rel)

            if after:

                move_file = False

            else:

                move_file = True

            if to_missing:

                if not move_file:

                    raise errors.BzrMoveFailedError(from_rel, to_rel,

                        errors.NoSuchFile(path=to_rel,

                        extra="New file has not been created yet"))

                elif from_missing:

                    # neither path exists

                    raise errors.BzrRenameFailedError(from_rel, to_rel,

                        errors.PathsDoNotExist(paths=(from_rel, to_rel)))

            else:

                if from_missing: # implicitly just update our path mapping

                    move_file = False

                else:

                    raise errors.RenameFailedFilesExist(from_rel, to_rel,

                        extra="(Use --after to update the Bazaar id)")

            rollbacks = []

            def rollback_rename():

                """A single rename has failed, roll it back."""

                error = None

                for rollback in reversed(rollbacks):

                    try:

                        rollback()

                    except e:

                        error = e

                if error:

                    raise error

            # perform the disk move first - its the most likely failure point.

            from_rel_abs = self.abspath(from_rel)

            to_rel_abs = self.abspath(to_rel)

            try:

                osutils.rename(from_rel_abs, to_rel_abs)

            except OSError, e:

                raise errors.BzrMoveFailedError(from_rel, to_rel, e[1])

            rollbacks.append(lambda: osutils.rename(to_rel_abs, from_rel_abs))

            try:

                # perform the rename in the inventory next if needed: its easy

                # to rollback

                if update_inventory:

                    # rename the entry

                    from_entry = inv[from_id]

                    current_parent = from_entry.parent_id

                    inv.rename(from_id, to_dir_id, from_tail)

                    rollbacks.append(

                        lambda: inv.rename(from_id, current_parent, from_tail))

                # finally do the rename in the dirstate, which is a little

                # tricky to rollback, but least likely to need it.

                basename = from_tail.encode('utf8')

                old_block_index, old_row_index, dir_present, file_present = \

                    self._get_block_row_index(from_dirname, basename)

                old_block = state._dirblocks[old_block_index][1]

                # remove the old row

                old_row = old_block.pop(old_row_index)

                rollbacks.append(lambda:old_block.insert(old_row_index, old_row))

                # create new row in current block

                new_row = ((to_block[0],) + old_row[0][1:], old_row[1])

                insert_position = bisect_left(to_block[1], new_row)

                to_block[1].insert(insert_position, new_row)

                rollbacks.append(lambda:to_block[1].pop(insert_position))

                if new_row[0][2] == 'directory':

                    import pdb;pdb.set_trace()

                    # if a directory, rename all the contents of child blocks

                    # adding rollbacks as each is inserted to remove them and

                    # restore the original

                    # TODO: large scale slice assignment.

                    # setup new list

                    # save old list region

                    # move up or down the old region

                    # add rollback to move the region back

                    # assign new list to new region

                    # done

            except:

                rollback_rename()

                raise

            state._dirblock_state = dirstate.DirState.IN_MEMORY_MODIFIED

            self._dirty = True

        return #rename_tuples

    def _new_tree(self):

        """Initialize the state in this tree to be a new tree."""

        self._dirty = True

    @needs_read_lock

    def path2id(self, path):

        """Return the id for path in this tree."""

        state = self.current_dirstate()

        row = self._get_row(path=path)

        if row == (None, None):

            return None

        return row[0][3].decode('utf8')

    def read_working_inventory(self):

        """Read the working inventory.

        This is a meaningless operation for dirstate, but we obey it anyhow.

        """

        return self.inventory

    @needs_read_lock

    def revision_tree(self, revision_id):

        """See Tree.revision_tree.

        WorkingTree4 supplies revision_trees for any basis tree.

        """

        dirstate = self.current_dirstate()

        parent_ids = dirstate.get_parent_ids()

        if revision_id not in parent_ids:

            raise errors.NoSuchRevisionInTree(self, revision_id)

        if revision_id in dirstate.get_ghosts():

            raise errors.NoSuchRevisionInTree(self, revision_id)

        return DirStateRevisionTree(dirstate, revision_id,

            self.branch.repository)

    @needs_tree_write_lock

    def set_last_revision(self, new_revision):

        """Change the last revision in the working tree."""

        parents = self.get_parent_ids()

        if new_revision in (NULL_REVISION, None):

            assert len(parents) < 2, (

                "setting the last parent to none with a pending merge is "

                "unsupported.")

            self.set_parent_ids([])

        else:

            self.set_parent_ids([new_revision] + parents[1:],

                allow_leftmost_as_ghost=True)

    @needs_tree_write_lock

    def set_parent_ids(self, revision_ids, allow_leftmost_as_ghost=False):

        """Set the parent ids to revision_ids.

        See also set_parent_trees. This api will try to retrieve the tree data

        for each element of revision_ids from the trees repository. If you have

        tree data already available, it is more efficient to use

        set_parent_trees rather than set_parent_ids. set_parent_ids is however

        an easier API to use.

        :param revision_ids: The revision_ids to set as the parent ids of this

            working tree. Any of these may be ghosts.

        """

        trees = []

        for revision_id in revision_ids:

            try:

                revtree = self.branch.repository.revision_tree(revision_id)

                # TODO: jam 20070213 KnitVersionedFile raises

                #       RevisionNotPresent rather than NoSuchRevision if a

                #       given revision_id is not present. Should Repository be

                #       catching it and re-raising NoSuchRevision?

            except (errors.NoSuchRevision, errors.RevisionNotPresent):

                revtree = None

            trees.append((revision_id, revtree))

        self.set_parent_trees(trees,

            allow_leftmost_as_ghost=allow_leftmost_as_ghost)

    @needs_tree_write_lock

    def set_parent_trees(self, parents_list, allow_leftmost_as_ghost=False):

        """Set the parents of the working tree.

        :param parents_list: A list of (revision_id, tree) tuples. 

            If tree is None, then that element is treated as an unreachable

            parent tree - i.e. a ghost.

        """

        dirstate = self.current_dirstate()

        if len(parents_list) > 0:

            if not allow_leftmost_as_ghost and parents_list[0][1] is None:

                raise errors.GhostRevisionUnusableHere(parents_list[0][0])

        real_trees = []

        ghosts = []

        # convert absent trees to the null tree, which we convert back to 

        # missing on access.

        for rev_id, tree in parents_list:

            if tree is not None:

                real_trees.append((rev_id, tree))

            else:

                real_trees.append((rev_id,

                    self.branch.repository.revision_tree(None)))

                ghosts.append(rev_id)

        dirstate.set_parent_trees(real_trees, ghosts=ghosts)

        self._dirty = True

    def _set_root_id(self, file_id):

        """See WorkingTree.set_root_id."""

        state = self.current_dirstate()

        state.set_path_id('', file_id)

        self._dirty = state._dirblock_state == dirstate.DirState.IN_MEMORY_MODIFIED

    def unlock(self):

        """Unlock in format 4 trees needs to write the entire dirstate."""

        if self._control_files._lock_count == 1:

            self._write_hashcache_if_dirty()

            # eventually we should do signature checking during read locks for

            # dirstate updates.

            if self._control_files._lock_mode == 'w':

                if self._dirty:

                    self.flush()

            self._dirstate = None

            self._inventory = None

        # reverse order of locking.

        try:

            return self._control_files.unlock()

        finally:

            self.branch.unlock()

    @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.

        """

        if not file_ids:

            return

        state = self.current_dirstate()

        state._read_dirblocks_if_needed()

        ids_to_unversion = set()

        for fileid in file_ids:

            ids_to_unversion.add(fileid.encode('utf8'))

        paths_to_unversion = set()

        # sketch:

        # check if the root is to be unversioned, if so, assert for now.

        # make a copy of the _dirblocks data 

        # during the copy,

        #  skip paths in paths_to_unversion

        #  skip ids in ids_to_unversion, and add their paths to

        #  paths_to_unversion if they are a directory

        # if there are any un-unversioned ids at the end, raise

        if state._root_row[0][3] in ids_to_unversion:

            # I haven't written the code to unversion / yet - it should be 

            # supported.

            raise errors.BzrError('Unversioning the / is not currently supported')

        new_blocks = []

        deleted_rows = []

        for block in state._dirblocks:

            # first check: is the path one to remove - it or its children

            delete_block = False

            for path in paths_to_unversion:

                if (block[0].startswith(path) and

                    (len(block[0]) == len(path) or

                     block[0][len(path)] == '/')):

                    # this path should be deleted

                    delete_block = True

                    break

            # TODO: trim paths_to_unversion as we pass by paths

            if delete_block:

                # this block is to be deleted. skip it.

                continue

            # copy undeleted rows from within the the block

            new_blocks.append((block[0], []))

            new_row = new_blocks[-1][1]

            for row, row_parents in block[1]:

                if row[3] not in ids_to_unversion:

                    new_row.append((row, row_parents))

                else:

                    # skip the row, and if its a dir mark its path to be removed

                    if row[2] == 'directory':

                        paths_to_unversion.add((row[0] + '/' + row[1]).strip('/'))

                    if row_parents:

                        deleted_rows.append((row[3], row_parents))

                    ids_to_unversion.remove(row[3])

        if ids_to_unversion:

            raise errors.NoSuchId(self, iter(ids_to_unversion).next())

        state._dirblocks = new_blocks

        for fileid_utf8, parents in deleted_rows:

            state.add_deleted(fileid_utf8, parents)

        state._dirblock_state = dirstate.DirState.IN_MEMORY_MODIFIED

        self._dirty = True

        # have to change the legacy inventory too.

        if self._inventory is not None:

            for file_id in file_ids:

                self._inventory.remove_recursive_id(file_id)

    @needs_tree_write_lock

    def _write_inventory(self, inv):

        """Write inventory as the current inventory."""

        assert not self._dirty, "attempting to write an inventory when the dirstate is dirty will cause data loss"

        self.current_dirstate().set_state_from_inventory(inv)

        self._dirty = True

        self.flush()

class WorkingTreeFormat4(WorkingTreeFormat3):

    """The first consolidated dirstate working tree format.

    This format:

        - exists within a metadir controlling .bzr

        - includes an explicit version marker for the workingtree control

          files, separate from the BzrDir format

        - modifies the hash cache format

        - is new in bzr TODO FIXME SETBEFOREMERGE

        - uses a LockDir to guard access to it.

    """

    def get_format_string(self):

        """See WorkingTreeFormat.get_format_string()."""