~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2007, 2008, 2009 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

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

from bzrlib import (

    bzrdir,

    commit,

    errors,

    memorytree,

    revision,

    )

class BranchBuilder(object):

    r"""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:

    >>> from bzrlib.transport.memory import MemoryTransport

    >>> builder = BranchBuilder(MemoryTransport("memory:///"))

    >>> builder.start_series()

    >>> builder.build_snapshot('rev-id', None, [

    ...     ('add', ('', 'root-id', 'directory', '')),

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

    'rev-id'

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

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

    'rev2-id'

    >>> 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=None, format=None, branch=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.

        :param branch: An already constructed branch to use.  This param is

            mutually exclusive with the transport and format params.

        """

        if branch is not None:

            if format is not None:

                raise AssertionError(

                    "branch and format kwargs are mutually exclusive")

            if transport is not None:

                raise AssertionError(

                    "branch and transport kwargs are mutually exclusive")

            self._branch = branch

        else:

            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, **commit_kwargs):

        """Build a commit on the branch.

        This makes a commit with no real file content for when you only want

        to look at the revision graph structure.

        :param commit_kwargs: Arguments to pass through to commit, such as

             timestamp.

        """

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

        tree.lock_write()

        try:

            tree.add('')

            return self._do_commit(tree, **commit_kwargs)

        finally:

            tree.unlock()

    def _do_commit(self, tree, message=None, message_callback=None, **kwargs):

        reporter = commit.NullCommitReporter()

        if message is None and message_callback is None:

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

        return tree.commit(message, message_callback=message_callback,

            reporter=reporter,

            **kwargs)

    def _move_branch_pointer(self, new_revision_id,

        allow_leftmost_as_ghost=False):

        """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()

            try:

                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)

            except errors.GhostRevisionsHaveNoRevno:

                if not allow_leftmost_as_ghost:

                    raise

                new_revno = 1

        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, timestamp=None, allow_leftmost_as_ghost=False,

        committer=None, timezone=None, message_callback=None):

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

        Most of the actions are self-explanatory.  'flush' is special action to

        break a series of actions into discrete steps so that complex changes

        (such as unversioning a file-id and re-adding it with a different kind)

        can be expressed in a way that will clearly work.

        :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')

            ('rename', ('orig-path', 'new-path'))

            ('flush', None)

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

            commit message will be written.

        :param message_callback: A message callback to use for the commit, as

            per mutabletree.commit.

        :param timestamp: If non-None, set the timestamp of the commit to this

            value.

        :param timezone: An optional timezone for timestamp.

        :param committer: An optional username to use for commit

        :param allow_leftmost_as_ghost: True if the leftmost parent should be

            permitted to be a ghost.

        :return: The revision_id of the new commit

        """

        if parent_ids is not None:

            if len(parent_ids) == 0:

                base_id = revision.NULL_REVISION

            else:

                base_id = parent_ids[0]

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

                self._move_branch_pointer(base_id,

                    allow_leftmost_as_ghost=allow_leftmost_as_ghost)

        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,

                    allow_leftmost_as_ghost=allow_leftmost_as_ghost)

            # 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.

            pending = _PendingActions()

            for action, info in actions:

                if action == 'add':

                    path, file_id, kind, content = info

                    if kind == 'directory':

                        pending.to_add_directories.append((path, file_id))

                    else:

                        pending.to_add_files.append(path)

                        pending.to_add_file_ids.append(file_id)

                        pending.to_add_kinds.append(kind)

                        if content is not None:

                            pending.new_contents[file_id] = content

                elif action == 'modify':

                    file_id, content = info

                    pending.new_contents[file_id] = content

                elif action == 'unversion':

                    pending.to_unversion_ids.add(info)

                elif action == 'rename':

                    from_relpath, to_relpath = info

                    pending.to_rename.append((from_relpath, to_relpath))

                elif action == 'flush':

                    self._flush_pending(tree, pending)

                    pending = _PendingActions()

                else:

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

            self._flush_pending(tree, pending)

            return self._do_commit(tree, message=message, rev_id=revision_id,

                timestamp=timestamp, timezone=timezone, committer=committer,

                message_callback=message_callback)

        finally:

            tree.unlock()

    def _flush_pending(self, tree, pending):

        """Flush the pending actions in 'pending', i.e. apply them to 'tree'."""

        for path, file_id in pending.to_add_directories:

            if path == '':

                old_id = tree.path2id(path)

                if old_id is not None and old_id in pending.to_unversion_ids:

                    # We're overwriting this path, no need to unversion

                    pending.to_unversion_ids.discard(old_id)

                # Special case, because the path already exists

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

            else:

                tree.mkdir(path, file_id)

        for from_relpath, to_relpath in pending.to_rename:

            tree.rename_one(from_relpath, to_relpath)

        if pending.to_unversion_ids:

            tree.unversion(pending.to_unversion_ids)

        tree.add(pending.to_add_files, pending.to_add_file_ids, pending.to_add_kinds)

        for file_id, content in pending.new_contents.iteritems():

            tree.put_file_bytes_non_atomic(file_id, content)

    def get_branch(self):

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

        return self._branch

class _PendingActions(object):

    """Pending actions for build_snapshot to take.

    This is just a simple class to hold a bunch of the intermediate state of

    build_snapshot in single object.

    """

    def __init__(self):

        self.to_add_directories = []

        self.to_add_files = []

        self.to_add_file_ids = []

        self.to_add_kinds = []

        self.new_contents = {}

        self.to_unversion_ids = set()

        self.to_rename = []