~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2007, 2008 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

"""Utility for create branches with particular contents."""

from bzrlib import bzrdir, errors, memorytree

class BranchBuilder(object):

    """A BranchBuilder aids creating Branches with particular shapes.

    The expected way to use BranchBuilder is to construct a

    BranchBuilder on the transport you want your branch on, and then call

    appropriate build_ methods on it to get the shape of history you want.

    This is meant as a helper for the test suite, not as a general class for

    real data.

    For instance:

      builder = BranchBuilder(self.get_transport().clone('relpath'))

      builder.start_series()

      builder.build_snapshot('rev-id', [],

        [('add', ('filename', 'f-id', 'file', 'content\n'))])

      builder.build_snapshot('rev2-id', ['rev-id'],

        [('modify', ('f-id', 'new-content\n'))])

      builder.finish_series()

      branch = builder.get_branch()

    :ivar _tree: This is a private member which is not meant to be modified by

        users of this class. While a 'series' is in progress, it should hold a

        MemoryTree with the contents of the last commit (ready to be modified

        by the next build_snapshot command) with a held write lock. Outside of

        a series in progress, it should be None.

    """

    def __init__(self, transport, format=None):

        """Construct a BranchBuilder on transport.

        :param transport: The transport the branch should be created on.

            If the path of the transport does not exist but its parent does

            it will be created.

        :param format: Either a BzrDirFormat, or the name of a format in the

            bzrdir format registry for the branch to be built.

        """

        if not transport.has('.'):

            transport.mkdir('.')

        if format is None:

            format = 'default'

        if isinstance(format, str):

            format = bzrdir.format_registry.make_bzrdir(format)

        self._branch = bzrdir.BzrDir.create_branch_convenience(transport.base,

            format=format, force_new_tree=False)

        self._tree = None

    def build_commit(self):

        """Build a commit on the branch."""

        tree = memorytree.MemoryTree.create_on_branch(self._branch)

        tree.lock_write()

        try:

            tree.add('')

            return tree.commit('commit %d' % (self._branch.revno() + 1))

        finally:

            tree.unlock()

    def _move_branch_pointer(self, new_revision_id):

        """Point self._branch to a different revision id."""

        self._branch.lock_write()

        try:

            # We don't seem to have a simple set_last_revision(), so we

            # implement it here.

            cur_revno, cur_revision_id = self._branch.last_revision_info()

            g = self._branch.repository.get_graph()

            new_revno = g.find_distance_to_null(new_revision_id,

                                                [(cur_revision_id, cur_revno)])

            self._branch.set_last_revision_info(new_revno, new_revision_id)

        finally:

            self._branch.unlock()

        if self._tree is not None:

            # We are currently processing a series, but when switching branch

            # pointers, it is easiest to just create a new memory tree.

            # That way we are sure to have the right files-on-disk

            # We are cheating a little bit here, and locking the new tree

            # before the old tree is unlocked. But that way the branch stays

            # locked throughout.

            new_tree = memorytree.MemoryTree.create_on_branch(self._branch)

            new_tree.lock_write()

            self._tree.unlock()

            self._tree = new_tree

    def start_series(self):

        """We will be creating a series of commits.

        This allows us to hold open the locks while we are processing.

        Make sure to call 'finish_series' when you are done.

        """

        if self._tree is not None:

            raise AssertionError('You cannot start a new series while a'

                                 ' series is already going.')

        self._tree = memorytree.MemoryTree.create_on_branch(self._branch)

        self._tree.lock_write()

    def finish_series(self):

        """Call this after start_series to unlock the various objects."""

        self._tree.unlock()

        self._tree = None

    def build_snapshot(self, revision_id, parent_ids, actions,

                       message=None):

        """Build a commit, shaped in a specific way.

        :param revision_id: The handle for the new commit, can be None

        :param parent_ids: A list of parent_ids to use for the commit.

            It can be None, which indicates to use the last commit.

        :param actions: A list of actions to perform. Supported actions are:

            ('add', ('path', 'file-id', 'kind', 'content' or None))

            ('modify', ('file-id', 'new-content'))

            ('unversion', 'file-id')

            # not supported yet: ('rename', ('orig-path', 'new-path'))

        :param message: An optional commit message, if not supplied, a default

            commit message will be written.

        :return: The revision_id of the new commit

        """

        if parent_ids is not None:

            base_id = parent_ids[0]

            if base_id != self._branch.last_revision():

                self._move_branch_pointer(base_id)

        if self._tree is not None:

            tree = self._tree

        else:

            tree = memorytree.MemoryTree.create_on_branch(self._branch)

        tree.lock_write()

        try:

            if parent_ids is not None:

                tree.set_parent_ids(parent_ids)

            # Unfortunately, MemoryTree.add(directory) just creates an

            # inventory entry. And the only public function to create a

            # directory is MemoryTree.mkdir() which creates the directory, but

            # also always adds it. So we have to use a multi-pass setup.

            to_add_directories = []

            to_add_files = []

            to_add_file_ids = []

            to_add_kinds = []

            new_contents = {}

            to_unversion_ids = []

            # TODO: MemoryTree doesn't support rename() or

            #       apply_inventory_delta, so we'll postpone allowing renames

            #       for now

            # to_rename = []

            for action, info in actions:

                if action == 'add':

                    path, file_id, kind, content = info

                    if kind == 'directory':

                        to_add_directories.append((path, file_id))

                    else:

                        to_add_files.append(path)

                        to_add_file_ids.append(file_id)

                        to_add_kinds.append(kind)

                        if content is not None:

                            new_contents[file_id] = content

                elif action == 'modify':

                    file_id, content = info

                    new_contents[file_id] = content

                elif action == 'unversion':

                    to_unversion_ids.append(info)

                else:

                    raise ValueError('Unknown build action: "%s"' % (action,))

            if to_unversion_ids:

                tree.unversion(to_unversion_ids)

            for path, file_id in to_add_directories:

                if path == '':

                    # Special case, because the path already exists

                    tree.add([path], [file_id], ['directory'])

                else:

                    tree.mkdir(path, file_id)

            tree.add(to_add_files, to_add_file_ids, to_add_kinds)

            for file_id, content in new_contents.iteritems():

                tree.put_file_bytes_non_atomic(file_id, content)

            if message is None:

                message = u'commit %d' % (self._branch.revno() + 1,)

            return tree.commit(message, rev_id=revision_id)

        finally:

            tree.unlock()

    def get_branch(self):

        """Return the branch created by the builder."""

        return self._branch