~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2005 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

from copy import deepcopy
from cStringIO import StringIO
from unittest import TestSuite
import xml.sax.saxutils


import bzrlib.bzrdir as bzrdir
from bzrlib.decorators import needs_read_lock, needs_write_lock
import bzrlib.errors as errors
from bzrlib.errors import InvalidRevisionId
from bzrlib.lockable_files import LockableFiles
from bzrlib.osutils import safe_unicode
from bzrlib.revision import NULL_REVISION
from bzrlib.store import copy_all
from bzrlib.store.weave import WeaveStore
from bzrlib.store.text import TextStore
from bzrlib.symbol_versioning import *
from bzrlib.trace import mutter
from bzrlib.tree import RevisionTree
from bzrlib.testament import Testament
from bzrlib.tree import EmptyTree
import bzrlib.xml5


class Repository(object):
    """Repository holding history for one or more branches.

    The repository holds and retrieves historical information including
    revisions and file history.  It's normally accessed only by the Branch,
    which views a particular line of development through that history.

    The Repository builds on top of Stores and a Transport, which respectively 
    describe the disk data format and the way of accessing the (possibly 
    remote) disk.
    """

    @needs_read_lock
    def _all_possible_ids(self):
        """Return all the possible revisions that we could find."""
        return self.get_inventory_weave().names()

    @needs_read_lock
    def all_revision_ids(self):
        """Returns a list of all the revision ids in the repository. 

        These are in as much topological order as the underlying store can 
        present: for weaves ghosts may lead to a lack of correctness until
        the reweave updates the parents list.
        """
        result = self._all_possible_ids()
        return self._eliminate_revisions_not_present(result)

    @needs_read_lock
    def _eliminate_revisions_not_present(self, revision_ids):
        """Check every revision id in revision_ids to see if we have it.

        Returns a set of the present revisions.
        """
        result = []
        for id in revision_ids:
            if self.has_revision(id):
               result.append(id)
        return result

    @staticmethod
    def create(a_bzrdir):
        """Construct the current default format repository in a_bzrdir."""
        return RepositoryFormat.get_default_format().initialize(a_bzrdir)

    def __init__(self, _format, a_bzrdir):
        object.__init__(self)
        if isinstance(_format, (RepositoryFormat4,
                                RepositoryFormat5,
                                RepositoryFormat6)):
            # legacy: use a common control files.
            self.control_files = a_bzrdir._control_files
        else:
            self.control_files = LockableFiles(a_bzrdir.get_repository_transport(None),
                                               'lock')

        dir_mode = self.control_files._dir_mode
        file_mode = self.control_files._file_mode
        self._format = _format
        self.bzrdir = a_bzrdir

        def get_weave(name, prefixed=False):
            if name:
                name = safe_unicode(name)
            else:
                name = ''
            relpath = self.control_files._escape(name)
            weave_transport = self.control_files._transport.clone(relpath)
            ws = WeaveStore(weave_transport, prefixed=prefixed,
                            dir_mode=dir_mode,
                            file_mode=file_mode)
            if self.control_files._transport.should_cache():
                ws.enable_cache = True
            return ws

        def get_store(name, compressed=True, prefixed=False):
            # FIXME: This approach of assuming stores are all entirely compressed
            # or entirely uncompressed is tidy, but breaks upgrade from 
            # some existing branches where there's a mixture; we probably 
            # still want the option to look for both.
            if name:
                name = safe_unicode(name)
            else:
                name = ''
            relpath = self.control_files._escape(name)
            store = TextStore(self.control_files._transport.clone(relpath),
                              prefixed=prefixed, compressed=compressed,
                              dir_mode=dir_mode,
                              file_mode=file_mode)
            #if self._transport.should_cache():
            #    cache_path = os.path.join(self.cache_root, name)
            #    os.mkdir(cache_path)
            #    store = bzrlib.store.CachedStore(store, cache_path)
            return store

        if isinstance(self._format, RepositoryFormat4):
            self.inventory_store = get_store('inventory-store')
            self.text_store = get_store('text-store')
            self.revision_store = get_store('revision-store')
        elif isinstance(self._format, RepositoryFormat5):
            self.control_weaves = get_weave('')
            self.weave_store = get_weave('weaves')
            self.revision_store = get_store('revision-store', compressed=False)
        elif isinstance(self._format, RepositoryFormat6):
            self.control_weaves = get_weave('')
            self.weave_store = get_weave('weaves', prefixed=True)
            self.revision_store = get_store('revision-store', compressed=False,
                                            prefixed=True)
        elif isinstance(self._format, RepositoryFormat7):
            self.control_weaves = get_weave('')
            self.weave_store = get_weave('weaves', prefixed=True)
            self.revision_store = get_store('revision-store', compressed=False,
                                            prefixed=True)
        self.revision_store.register_suffix('sig')

    def lock_write(self):
        self.control_files.lock_write()

    def lock_read(self):
        self.control_files.lock_read()

    @needs_read_lock
    def missing_revision_ids(self, other, revision_id=None):
        """Return the revision ids that other has that this does not.
        
        These are returned in topological order.

        revision_id: only return revision ids included by revision_id.
        """
        if self._compatible_formats(other):
            # fast path for weave-inventory based stores.
            # we want all revisions to satisft revision_id in other.
            # but we dont want to stat every file here and there.
            # we want then, all revisions other needs to satisfy revision_id 
            # checked, but not those that we have locally.
            # so the first thing is to get a subset of the revisions to 
            # satisfy revision_id in other, and then eliminate those that
            # we do already have. 
            # this is slow on high latency connection to self, but as as this
            # disk format scales terribly for push anyway due to rewriting 
            # inventory.weave, this is considered acceptable.
            # - RBC 20060209
            if revision_id is not None:
                other_ids = other.get_ancestry(revision_id)
                assert other_ids.pop(0) == None
            else:
                other_ids = other._all_possible_ids()
            other_ids_set = set(other_ids)
            # other ids is the worst case to pull now.
            # now we want to filter other_ids against what we actually
            # have, but dont try to stat what we know we dont.
            my_ids = set(self._all_possible_ids())
            possibly_present_revisions = my_ids.intersection(other_ids_set)
            actually_present_revisions = set(self._eliminate_revisions_not_present(possibly_present_revisions))
            required_revisions = other_ids_set.difference(actually_present_revisions)
            required_topo_revisions = [rev_id for rev_id in other_ids if rev_id in required_revisions]
            if revision_id is not None:
                # we used get_ancestry to determine other_ids then we are assured all
                # revisions referenced are present as they are installed in topological order.
                return required_topo_revisions
            else:
                # we only have an estimate of whats available
                return other._eliminate_revisions_not_present(required_topo_revisions)
        # slow code path.
        my_ids = set(self.all_revision_ids())
        if revision_id is not None:
            other_ids = other.get_ancestry(revision_id)
            assert other_ids.pop(0) == None
        else:
            other_ids = other.all_revision_ids()
        result_set = set(other_ids).difference(my_ids)
        return [rev_id for rev_id in other_ids if rev_id in result_set]

    @staticmethod
    def open(base):
        """Open the repository rooted at base.

        For instance, if the repository is at URL/.bzr/repository,
        Repository.open(URL) -> a Repository instance.
        """
        control = bzrdir.BzrDir.open(base)
        return control.open_repository()

    def _compatible_formats(self, other):
        """Return True if the stores in self and other are 'compatible'
        
        'compatible' means that they are both the same underlying type
        i.e. both weave stores, or both knits and thus support fast-path
        operations."""
        return (isinstance(self._format, (RepositoryFormat5,
                                          RepositoryFormat6,
                                          RepositoryFormat7)) and
                isinstance(other._format, (RepositoryFormat5,
                                           RepositoryFormat6,
                                           RepositoryFormat7)))

    @needs_read_lock
    def copy_content_into(self, destination, revision_id=None, basis=None):
        """Make a complete copy of the content in self into destination.
        
        This is a destructive operation! Do not use it on existing 
        repositories.
        """
        destination.lock_write()
        try:
            try:
                destination.set_make_working_trees(self.make_working_trees())
            except NotImplementedError:
                pass
            # optimised paths:
            # compatible stores
            if self._compatible_formats(destination):
                if basis is not None:
                    # copy the basis in, then fetch remaining data.
                    basis.copy_content_into(destination, revision_id)
                    destination.fetch(self, revision_id=revision_id)
                else:
                    # FIXME do not peek!
                    if self.control_files._transport.listable():
                        destination.control_weaves.copy_multi(self.control_weaves,
                                                              ['inventory'])
                        copy_all(self.weave_store, destination.weave_store)
                        copy_all(self.revision_store, destination.revision_store)
                    else:
                        destination.fetch(self, revision_id=revision_id)
            # compatible v4 stores
            elif isinstance(self._format, RepositoryFormat4):
                if not isinstance(destination._format, RepositoryFormat4):
                    raise BzrError('cannot copy v4 branches to anything other than v4 branches.')
                store_pairs = ((self.text_store,      destination.text_store),
                               (self.inventory_store, destination.inventory_store),
                               (self.revision_store,  destination.revision_store))
                try:
                    for from_store, to_store in store_pairs: 
                        copy_all(from_store, to_store)
                except UnlistableStore:
                    raise UnlistableBranch(from_store)
            # fallback - 'fetch'
            else:
                destination.fetch(self, revision_id=revision_id)
        finally:
            destination.unlock()

    @needs_write_lock
    def fetch(self, source, revision_id=None):
        """Fetch the content required to construct revision_id from source.

        If revision_id is None all content is copied.
        """
        from bzrlib.fetch import RepoFetcher
        mutter("Using fetch logic to copy between %s(%s) and %s(%s)",
               source, source._format, self, self._format)
        RepoFetcher(to_repository=self, from_repository=source, last_revision=revision_id)

    def unlock(self):
        self.control_files.unlock()

    @needs_read_lock
    def clone(self, a_bzrdir, revision_id=None, basis=None):
        """Clone this repository into a_bzrdir using the current format.

        Currently no check is made that the format of this repository and
        the bzrdir format are compatible. FIXME RBC 20060201.
        """
        if not isinstance(a_bzrdir._format, self.bzrdir._format.__class__):
            # use target default format.
            result = a_bzrdir.create_repository()
        # FIXME RBC 20060209 split out the repository type to avoid this check ?
        elif isinstance(a_bzrdir._format,
                      (bzrdir.BzrDirFormat4,
                       bzrdir.BzrDirFormat5,
                       bzrdir.BzrDirFormat6)):
            result = a_bzrdir.open_repository()
        else:
            result = self._format.initialize(a_bzrdir, shared=self.is_shared())
        self.copy_content_into(result, revision_id, basis)
        return result

    def has_revision(self, revision_id):
        """True if this branch has a copy of the revision.

        This does not necessarily imply the revision is merge
        or on the mainline."""
        return (revision_id is None
                or self.revision_store.has_id(revision_id))

    @needs_read_lock
    def get_revision_xml_file(self, revision_id):
        """Return XML file object for revision object."""
        if not revision_id or not isinstance(revision_id, basestring):
            raise InvalidRevisionId(revision_id=revision_id, branch=self)
        try:
            return self.revision_store.get(revision_id)
        except (IndexError, KeyError):
            raise bzrlib.errors.NoSuchRevision(self, revision_id)

    @needs_read_lock
    def get_revision_xml(self, revision_id):
        return self.get_revision_xml_file(revision_id).read()

    @needs_read_lock
    def get_revision(self, revision_id):
        """Return the Revision object for a named revision"""
        xml_file = self.get_revision_xml_file(revision_id)

        try:
            r = bzrlib.xml5.serializer_v5.read_revision(xml_file)
        except SyntaxError, e:
            raise bzrlib.errors.BzrError('failed to unpack revision_xml',
                                         [revision_id,
                                          str(e)])
            
        assert r.revision_id == revision_id
        return r

    @needs_read_lock
    def get_revision_sha1(self, revision_id):
        """Hash the stored value of a revision, and return it."""
        # In the future, revision entries will be signed. At that
        # point, it is probably best *not* to include the signature
        # in the revision hash. Because that lets you re-sign
        # the revision, (add signatures/remove signatures) and still
        # have all hash pointers stay consistent.
        # But for now, just hash the contents.
        return bzrlib.osutils.sha_file(self.get_revision_xml_file(revision_id))

    @needs_write_lock
    def store_revision_signature(self, gpg_strategy, plaintext, revision_id):
        self.revision_store.add(StringIO(gpg_strategy.sign(plaintext)), 
                                revision_id, "sig")

    def fileid_involved_between_revs(self, from_revid, to_revid):
        """Find file_id(s) which are involved in the changes between revisions.

        This determines the set of revisions which are involved, and then
        finds all file ids affected by those revisions.
        """
        # TODO: jam 20060119 This code assumes that w.inclusions will
        #       always be correct. But because of the presence of ghosts
        #       it is possible to be wrong.
        #       One specific example from Robert Collins:
        #       Two branches, with revisions ABC, and AD
        #       C is a ghost merge of D.
        #       Inclusions doesn't recognize D as an ancestor.
        #       If D is ever merged in the future, the weave
        #       won't be fixed, because AD never saw revision C
        #       to cause a conflict which would force a reweave.
        w = self.get_inventory_weave()
        from_set = set(w.inclusions([w.lookup(from_revid)]))
        to_set = set(w.inclusions([w.lookup(to_revid)]))
        included = to_set.difference(from_set)
        changed = map(w.idx_to_name, included)
        return self._fileid_involved_by_set(changed)

    def fileid_involved(self, last_revid=None):
        """Find all file_ids modified in the ancestry of last_revid.

        :param last_revid: If None, last_revision() will be used.
        """
        w = self.get_inventory_weave()
        if not last_revid:
            changed = set(w._names)
        else:
            included = w.inclusions([w.lookup(last_revid)])
            changed = map(w.idx_to_name, included)
        return self._fileid_involved_by_set(changed)

    def fileid_involved_by_set(self, changes):
        """Find all file_ids modified by the set of revisions passed in.

        :param changes: A set() of revision ids
        """
        # TODO: jam 20060119 This line does *nothing*, remove it.
        #       or better yet, change _fileid_involved_by_set so
        #       that it takes the inventory weave, rather than
        #       pulling it out by itself.
        return self._fileid_involved_by_set(changes)

    def _fileid_involved_by_set(self, changes):
        """Find the set of file-ids affected by the set of revisions.

        :param changes: A set() of revision ids.
        :return: A set() of file ids.
        
        This peaks at the Weave, interpreting each line, looking to
        see if it mentions one of the revisions. And if so, includes
        the file id mentioned.
        This expects both the Weave format, and the serialization
        to have a single line per file/directory, and to have
        fileid="" and revision="" on that line.
        """
        assert isinstance(self._format, (RepositoryFormat5,
                                         RepositoryFormat6,
                                         RepositoryFormat7)), \
            "fileid_involved only supported for branches which store inventory as unnested xml"

        w = self.get_inventory_weave()
        file_ids = set()
        for line in w._weave:

            # it is ugly, but it is due to the weave structure
            if not isinstance(line, basestring): continue

            start = line.find('file_id="')+9
            if start < 9: continue
            end = line.find('"', start)
            assert end>= 0
            file_id = xml.sax.saxutils.unescape(line[start:end])

            # check if file_id is already present
            if file_id in file_ids: continue

            start = line.find('revision="')+10
            if start < 10: continue
            end = line.find('"', start)
            assert end>= 0
            revision_id = xml.sax.saxutils.unescape(line[start:end])

            if revision_id in changes:
                file_ids.add(file_id)
        return file_ids

    @needs_read_lock
    def get_inventory_weave(self):
        return self.control_weaves.get_weave('inventory',
            self.get_transaction())

    @needs_read_lock
    def get_inventory(self, revision_id):
        """Get Inventory object by hash."""
        xml = self.get_inventory_xml(revision_id)
        return bzrlib.xml5.serializer_v5.read_inventory_from_string(xml)

    @needs_read_lock
    def get_inventory_xml(self, revision_id):
        """Get inventory XML as a file object."""
        try:
            assert isinstance(revision_id, basestring), type(revision_id)
            iw = self.get_inventory_weave()
            return iw.get_text(iw.lookup(revision_id))
        except IndexError:
            raise bzrlib.errors.HistoryMissing(self, 'inventory', revision_id)

    @needs_read_lock
    def get_inventory_sha1(self, revision_id):
        """Return the sha1 hash of the inventory entry
        """
        return self.get_revision(revision_id).inventory_sha1

    @needs_read_lock
    def get_revision_inventory(self, revision_id):
        """Return inventory of a past revision."""
        # TODO: Unify this with get_inventory()
        # bzr 0.0.6 and later imposes the constraint that the inventory_id
        # must be the same as its revision, so this is trivial.
        if revision_id is None:
            # This does not make sense: if there is no revision,
            # then it is the current tree inventory surely ?!
            # and thus get_root_id() is something that looks at the last
            # commit on the branch, and the get_root_id is an inventory check.
            raise NotImplementedError
            # return Inventory(self.get_root_id())
        else:
            return self.get_inventory(revision_id)

    @needs_read_lock
    def is_shared(self):
        """Return True if this repository is flagged as a shared repository."""
        # FIXME format 4-6 cannot be shared, this is technically faulty.
        return self.control_files._transport.has('shared-storage')

    @needs_read_lock
    def revision_tree(self, revision_id):
        """Return Tree for a revision on this branch.

        `revision_id` may be None for the null revision, in which case
        an `EmptyTree` is returned."""
        # TODO: refactor this to use an existing revision object
        # so we don't need to read it in twice.
        if revision_id is None or revision_id == NULL_REVISION:
            return EmptyTree()
        else:
            inv = self.get_revision_inventory(revision_id)
            return RevisionTree(self, inv, revision_id)

    @needs_read_lock
    def get_ancestry(self, revision_id):
        """Return a list of revision-ids integrated by a revision.
        
        This is topologically sorted.
        """
        if revision_id is None:
            return [None]
        if not self.has_revision(revision_id):
            raise errors.NoSuchRevision(self, revision_id)
        w = self.get_inventory_weave()
        return [None] + map(w.idx_to_name,
                            w.inclusions([w.lookup(revision_id)]))

    @needs_read_lock
    def print_file(self, file, revision_id):
        """Print `file` to stdout.
        
        FIXME RBC 20060125 as John Meinel points out this is a bad api
        - it writes to stdout, it assumes that that is valid etc. Fix
        by creating a new more flexible convenience function.
        """
        tree = self.revision_tree(revision_id)
        # use inventory as it was in that revision
        file_id = tree.inventory.path2id(file)
        if not file_id:
            raise BzrError("%r is not present in revision %s" % (file, revno))
            try:
                revno = self.revision_id_to_revno(revision_id)
            except errors.NoSuchRevision:
                # TODO: This should not be BzrError,
                # but NoSuchFile doesn't fit either
                raise BzrError('%r is not present in revision %s' 
                                % (file, revision_id))
            else:
                raise BzrError('%r is not present in revision %s'
                                % (file, revno))
        tree.print_file(file_id)

    def get_transaction(self):
        return self.control_files.get_transaction()

    @needs_write_lock
    def set_make_working_trees(self, new_value):
        """Set the policy flag for making working trees when creating branches.

        This only applies to branches that use this repository.

        The default is 'True'.
        :param new_value: True to restore the default, False to disable making
                          working trees.
        """
        # FIXME: split out into a new class/strategy ?
        if isinstance(self._format, (RepositoryFormat4,
                                     RepositoryFormat5,
                                     RepositoryFormat6)):
            raise NotImplementedError(self.set_make_working_trees)
        if new_value:
            try:
                self.control_files._transport.delete('no-working-trees')
            except errors.NoSuchFile:
                pass
        else:
            self.control_files.put_utf8('no-working-trees', '')
    
    def make_working_trees(self):
        """Returns the policy for making working trees on new branches."""
        # FIXME: split out into a new class/strategy ?
        if isinstance(self._format, (RepositoryFormat4,
                                     RepositoryFormat5,
                                     RepositoryFormat6)):
            return True
        return not self.control_files._transport.has('no-working-trees')

    @needs_write_lock
    def sign_revision(self, revision_id, gpg_strategy):
        plaintext = Testament.from_revision(self, revision_id).as_short_text()
        self.store_revision_signature(gpg_strategy, plaintext, revision_id)


class RepositoryFormat(object):
    """A repository format.

    Formats provide three things:
     * An initialization routine to construct repository data on disk.
     * a format string which is used when the BzrDir supports versioned
       children.
     * an open routine which returns a Repository instance.

    Formats are placed in an dict by their format string for reference 
    during opening. These should be subclasses of RepositoryFormat
    for consistency.

    Once a format is deprecated, just deprecate the initialize and open
    methods on the format class. Do not deprecate the object, as the 
    object will be created every system load.

    Common instance attributes:
    _matchingbzrdir - the bzrdir format that the repository format was
    originally written to work with. This can be used if manually
    constructing a bzrdir and repository, or more commonly for test suite
    parameterisation.
    """

    _default_format = None
    """The default format used for new repositories."""

    _formats = {}
    """The known formats."""

    @classmethod
    def find_format(klass, a_bzrdir):
        """Return the format for the repository object in a_bzrdir."""
        try:
            transport = a_bzrdir.get_repository_transport(None)
            format_string = transport.get("format").read()
            return klass._formats[format_string]
        except errors.NoSuchFile:
            raise errors.NoRepositoryPresent(a_bzrdir)
        except KeyError:
            raise errors.UnknownFormatError(format_string)

    @classmethod
    def get_default_format(klass):
        """Return the current default format."""
        return klass._default_format

    def get_format_string(self):
        """Return the ASCII format string that identifies this format.
        
        Note that in pre format ?? repositories the format string is 
        not permitted nor written to disk.
        """
        raise NotImplementedError(self.get_format_string)

    def initialize(self, a_bzrdir, shared=False):
        """Initialize a repository of this format in a_bzrdir.

        :param a_bzrdir: The bzrdir to put the new repository in it.
        :param shared: The repository should be initialized as a sharable one.

        This may raise UninitializableFormat if shared repository are not
        compatible the a_bzrdir.
        """

    def is_supported(self):
        """Is this format supported?

        Supported formats must be initializable and openable.
        Unsupported formats may not support initialization or committing or 
        some other features depending on the reason for not being supported.
        """
        return True

    def open(self, a_bzrdir, _found=False):
        """Return an instance of this format for the bzrdir a_bzrdir.
        
        _found is a private parameter, do not use it.
        """
        if not _found:
            # we are being called directly and must probe.
            raise NotImplementedError
        return Repository(_format=self, a_bzrdir=a_bzrdir)

    @classmethod
    def register_format(klass, format):
        klass._formats[format.get_format_string()] = format

    @classmethod
    def set_default_format(klass, format):
        klass._default_format = format

    @classmethod
    def unregister_format(klass, format):
        assert klass._formats[format.get_format_string()] is format
        del klass._formats[format.get_format_string()]


class PreSplitOutRepositoryFormat(RepositoryFormat):
    """Base class for the pre split out repository formats."""

    def initialize(self, a_bzrdir, shared=False, _internal=False):
        """Create a weave repository.
        
        TODO: when creating split out bzr branch formats, move this to a common
        base for Format5, Format6. or something like that.
        """
        from bzrlib.weavefile import write_weave_v5
        from bzrlib.weave import Weave

        if shared:
            raise errors.IncompatibleFormat(self, a_bzrdir._format)

        if not _internal:
            # always initialized when the bzrdir is.
            return Repository(_format=self, a_bzrdir=a_bzrdir)
        
        # Create an empty weave
        sio = StringIO()
        bzrlib.weavefile.write_weave_v5(Weave(), sio)
        empty_weave = sio.getvalue()

        mutter('creating repository in %s.', a_bzrdir.transport.base)
        dirs = ['revision-store', 'weaves']
        lock_file = 'branch-lock'
        files = [('inventory.weave', StringIO(empty_weave)), 
                 ]
        
        # FIXME: RBC 20060125 dont peek under the covers
        # NB: no need to escape relative paths that are url safe.
        control_files = LockableFiles(a_bzrdir.transport, 'branch-lock')
        control_files.lock_write()
        control_files._transport.mkdir_multi(dirs,
                mode=control_files._dir_mode)
        try:
            for file, content in files:
                control_files.put(file, content)
        finally:
            control_files.unlock()
        return Repository(_format=self, a_bzrdir=a_bzrdir)


class RepositoryFormat4(PreSplitOutRepositoryFormat):
    """Bzr repository format 4.

    This repository format has:
     - flat stores
     - TextStores for texts, inventories,revisions.

    This format is deprecated: it indexes texts using a text id which is
    removed in format 5; initializationa and write support for this format
    has been removed.
    """

    def __init__(self):
        super(RepositoryFormat4, self).__init__()
        self._matchingbzrdir = bzrdir.BzrDirFormat4()

    def initialize(self, url, shared=False, _internal=False):
        """Format 4 branches cannot be created."""
        raise errors.UninitializableFormat(self)

    def is_supported(self):
        """Format 4 is not supported.

        It is not supported because the model changed from 4 to 5 and the
        conversion logic is expensive - so doing it on the fly was not 
        feasible.
        """
        return False


class RepositoryFormat5(PreSplitOutRepositoryFormat):
    """Bzr control format 5.

    This repository format has:
     - weaves for file texts and inventory
     - flat stores
     - TextStores for revisions and signatures.
    """

    def __init__(self):
        super(RepositoryFormat5, self).__init__()
        self._matchingbzrdir = bzrdir.BzrDirFormat5()


class RepositoryFormat6(PreSplitOutRepositoryFormat):
    """Bzr control format 6.

    This repository format has:
     - weaves for file texts and inventory
     - hash subdirectory based stores.
     - TextStores for revisions and signatures.
    """

    def __init__(self):
        super(RepositoryFormat6, self).__init__()
        self._matchingbzrdir = bzrdir.BzrDirFormat6()


class RepositoryFormat7(RepositoryFormat):
    """Bzr repository 7.

    This repository format has:
     - weaves for file texts and inventory
     - hash subdirectory based stores.
     - TextStores for revisions and signatures.
     - a format marker of its own
     - an optional 'shared-storage' flag
    """

    def get_format_string(self):
        """See RepositoryFormat.get_format_string()."""
        return "Bazaar-NG Repository format 7"

    def initialize(self, a_bzrdir, shared=False):
        """Create a weave repository.

        :param shared: If true the repository will be initialized as a shared
                       repository.
        """
        from bzrlib.weavefile import write_weave_v5
        from bzrlib.weave import Weave

        # Create an empty weave
        sio = StringIO()
        bzrlib.weavefile.write_weave_v5(Weave(), sio)
        empty_weave = sio.getvalue()

        mutter('creating repository in %s.', a_bzrdir.transport.base)
        dirs = ['revision-store', 'weaves']
        files = [('inventory.weave', StringIO(empty_weave)), 
                 ]
        utf8_files = [('format', self.get_format_string())]
        
        # FIXME: RBC 20060125 dont peek under the covers
        # NB: no need to escape relative paths that are url safe.
        lock_file = 'lock'
        repository_transport = a_bzrdir.get_repository_transport(self)
        repository_transport.put(lock_file, StringIO()) # TODO get the file mode from the bzrdir lock files., mode=file_mode)
        control_files = LockableFiles(repository_transport, 'lock')
        control_files.lock_write()
        control_files._transport.mkdir_multi(dirs,
                mode=control_files._dir_mode)
        try:
            for file, content in files:
                control_files.put(file, content)
            for file, content in utf8_files:
                control_files.put_utf8(file, content)
            if shared == True:
                control_files.put_utf8('shared-storage', '')
        finally:
            control_files.unlock()
        return Repository(_format=self, a_bzrdir=a_bzrdir)

    def __init__(self):
        super(RepositoryFormat7, self).__init__()
        self._matchingbzrdir = bzrdir.BzrDirMetaFormat1()


# formats which have no format string are not discoverable
# and not independently creatable, so are not registered.
__default_format = RepositoryFormat7()
RepositoryFormat.register_format(__default_format)
RepositoryFormat.set_default_format(__default_format)
_legacy_formats = [RepositoryFormat4(),
                   RepositoryFormat5(),
                   RepositoryFormat6()]


# TODO: jam 20060108 Create a new branch format, and as part of upgrade
#       make sure that ancestry.weave is deleted (it is never used, but
#       used to be created)

class RepositoryTestProviderAdapter(object):
    """A tool to generate a suite testing multiple repository formats at once.

    This is done by copying the test once for each transport and injecting
    the transport_server, transport_readonly_server, and bzrdir_format and
    repository_format classes into each copy. Each copy is also given a new id()
    to make it easy to identify.
    """

    def __init__(self, transport_server, transport_readonly_server, formats):
        self._transport_server = transport_server
        self._transport_readonly_server = transport_readonly_server
        self._formats = formats
    
    def adapt(self, test):
        result = TestSuite()
        for repository_format, bzrdir_format in self._formats:
            new_test = deepcopy(test)
            new_test.transport_server = self._transport_server
            new_test.transport_readonly_server = self._transport_readonly_server
            new_test.bzrdir_format = bzrdir_format
            new_test.repository_format = repository_format
            def make_new_test_id():
                new_id = "%s(%s)" % (new_test.id(), repository_format.__class__.__name__)
                return lambda: new_id
            new_test.id = make_new_test_id()
            result.addTest(new_test)
        return result