~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2005, 2006, 2007, 2009, 2010 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

"""Serializer factory for reading and writing bundles.

"""

import base64

from StringIO import StringIO

import re

from bzrlib import (

    errors,

    pyutils,

    )

from bzrlib.diff import internal_diff

from bzrlib.revision import NULL_REVISION

# For backwards-compatibility

from bzrlib.timestamp import unpack_highres_date, format_highres_date

# New bundles should try to use this header format

BUNDLE_HEADER = '# Bazaar revision bundle v'

BUNDLE_HEADER_RE = re.compile(

    r'^# Bazaar revision bundle v(?P<version>\d+[\w.]*)(?P<lineending>\r?)\n$')

CHANGESET_OLD_HEADER_RE = re.compile(

    r'^# Bazaar-NG changeset v(?P<version>\d+[\w.]*)(?P<lineending>\r?)\n$')

_serializers = {}

v4_string = '4'

def _get_bundle_header(version):

    return '%s%s\n' % (BUNDLE_HEADER, version)

def _get_filename(f):

    return getattr(f, 'name', '<unknown>')

def read_bundle(f):

    """Read in a bundle from a filelike object.

    :param f: A file-like object

    :return: A list of Bundle objects

    """

    version = None

    for line in f:

        m = BUNDLE_HEADER_RE.match(line)

        if m:

            if m.group('lineending') != '':

                raise errors.UnsupportedEOLMarker()

            version = m.group('version')

            break

        elif line.startswith(BUNDLE_HEADER):

            raise errors.MalformedHeader(

                'Extra characters after version number')

        m = CHANGESET_OLD_HEADER_RE.match(line)

        if m:

            version = m.group('version')

            raise errors.BundleNotSupported(version,

                'old format bundles not supported')

    if version is None:

        raise errors.NotABundle('Did not find an opening header')

    # Now we have a version, to figure out how to read the bundle

    if version not in _serializers:

        raise errors.BundleNotSupported(version,

            'version not listed in known versions')

    serializer = _serializers[version](version)

    return serializer.read(f)

def get_serializer(version):

    try:

        return _serializers[version](version)

    except KeyError:

        raise errors.BundleNotSupported(version, 'unknown bundle format')

def write(source, revision_ids, f, version=None, forced_bases={}):

    """Serialize a list of bundles to a filelike object.

    :param source: A source for revision information

    :param revision_ids: The list of revision ids to serialize

    :param f: The file to output to

    :param version: [optional] target serialization version

    """

    source.lock_read()

    try:

        return get_serializer(version).write(source, revision_ids,

                                             forced_bases, f)

    finally:

        source.unlock()

def write_bundle(repository, revision_id, base_revision_id, out, format=None):

    """Write a bundle of revisions.

    :param repository: Repository containing revisions to serialize.

    :param revision_id: Head revision_id of the bundle.

    :param base_revision_id: Revision assumed to be present in repositories

         applying the bundle.

    :param out: Output file.

    """

    repository.lock_read()

    try:

        return get_serializer(format).write_bundle(repository, revision_id,

                                                   base_revision_id, out)

    finally:

        repository.unlock()

class BundleSerializer(object):

    """The base class for Serializers.

    Common functionality should be included here.

    """

    def __init__(self, version):

        self.version = version

    def read(self, f):

        """Read the rest of the bundles from the supplied file.

        :param f: The file to read from

        :return: A list of bundle trees

        """

        raise NotImplementedError

    def write_bundle(self, repository, target, base, fileobj):

        """Write the bundle to the supplied file.

        :param repository: The repository to retrieve revision data from

        :param target: The revision to provide data for

        :param base: The most recent of ancestor of the revision that does not

            need to be included in the bundle

        :param fileobj: The file to output to

        """

        raise NotImplementedError

    def _write_bundle(self, repository, revision_id, base_revision_id, out):

        """Helper function for translating write_bundle to write"""

        forced_bases = {revision_id:base_revision_id}

        if base_revision_id is NULL_REVISION:

            base_revision_id = None

        revision_ids = set(repository.get_ancestry(revision_id,

                           topo_sorted=False))

        revision_ids.difference_update(repository.get_ancestry(

            base_revision_id, topo_sorted=False))

        revision_ids = list(repository.get_graph().iter_topo_order(

            revision_ids))

        revision_ids.reverse()

        self.write(repository, revision_ids, forced_bases, out)

        return revision_ids

def register(version, klass, overwrite=False):

    """Register a BundleSerializer version.

    :param version: The version associated with this format

    :param klass: The class to instantiate, which must take a version argument

    """

    global _serializers

    if overwrite:

        _serializers[version] = klass

        return

    if version not in _serializers:

        _serializers[version] = klass

def register_lazy(version, module, classname, overwrite=False):

    """Register lazy-loaded bundle serializer.

    :param version: The version associated with this reader

    :param module: String indicating what module should be loaded

    :param classname: Name of the class that will be instantiated

    :param overwrite: Should this version override a default

    """

    def _loader(version):

        klass = pyutils.get_named_object(module, classname)

        return klass(version)

    register(version, _loader, overwrite=overwrite)

def binary_diff(old_filename, old_lines, new_filename, new_lines, to_file):

    temp = StringIO()

    internal_diff(old_filename, old_lines, new_filename, new_lines, temp,

                  allow_binary=True)

    temp.seek(0)

    base64.encode(temp, to_file)

    to_file.write('\n')

register_lazy('0.8', 'bzrlib.bundle.serializer.v08', 'BundleSerializerV08')

register_lazy('0.9', 'bzrlib.bundle.serializer.v09', 'BundleSerializerV09')

register_lazy(v4_string, 'bzrlib.bundle.serializer.v4',

              'BundleSerializerV4')

register_lazy(None, 'bzrlib.bundle.serializer.v4', 'BundleSerializerV4')