branch_updater.py

   1 # Copyright (C) 2009 Canonical Ltd
   2 #
   3 # This program is free software; you can redistribute it and/or modify
   4 # it under the terms of the GNU General Public License as published by
   5 # the Free Software Foundation; either version 2 of the License, or
   6 # (at your option) any later version.
   7 #
   8 # This program is distributed in the hope that it will be useful,
   9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 # GNU General Public License for more details.
  12 #
  13 # You should have received a copy of the GNU General Public License
  14 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15
  16 """An object that updates a bunch of branches based on data imported."""
  17
  18 from operator import itemgetter
  19
  20 from bzrlib import bzrdir, errors, osutils, transport
  21 from bzrlib.trace import show_error, note
  22
  23 from bzrlib.plugins.fastimport.helpers import (
  24     best_format_for_objects_in_a_repository,
  25     single_plural,
  26     )
  27
  28
  29 class BranchUpdater(object):
  30
  31     def __init__(self, repo, branch, cache_mgr, heads_by_ref, last_ref, tags):
  32         """Create an object responsible for updating branches.
  33
  34         :param heads_by_ref: a dictionary where
  35           names are git-style references like refs/heads/master;
  36           values are one item lists of commits marks.
  37         """
  38         self.repo = repo
  39         self.branch = branch
  40         self.cache_mgr = cache_mgr
  41         self.heads_by_ref = heads_by_ref
  42         self.last_ref = last_ref
  43         self.tags = tags
  44         self._branch_format = \
  45             best_format_for_objects_in_a_repository(repo)
  46
  47     def update(self):
  48         """Update the Bazaar branches and tips matching the heads.
  49
  50         If the repository is shared, this routine creates branches
  51         as required. If it isn't, warnings are produced about the
  52         lost of information.
  53
  54         :return: updated, lost_heads where
  55           updated = the list of branches updated ('trunk' is first)
  56           lost_heads = a list of (bazaar-name,revision) for branches that
  57             would have been created had the repository been shared
  58         """
  59         updated = []
  60         branch_tips, lost_heads = self._get_matching_branches()
  61         for br, tip in branch_tips:
  62             if self._update_branch(br, tip):
  63                 updated.append(br)
  64         return updated, lost_heads
  65
  66     def _get_matching_branches(self):
  67         """Get the Bazaar branches.
  68
  69         :return: branch_tips, lost_heads where
  70           branch_tips = a list of (branch,tip) tuples for branches. The
  71             first tip is the 'trunk'.
  72           lost_heads = a list of (bazaar-name,revision) for branches that
  73             would have been created had the repository been shared and
  74             everything succeeded
  75         """
  76         branch_tips = []
  77         lost_heads = []
  78         ref_names = self.heads_by_ref.keys()
  79         if self.branch is not None:
  80             trunk = self.select_trunk(ref_names)
  81             default_tip = self.heads_by_ref[trunk][0]
  82             branch_tips.append((self.branch, default_tip))
  83             ref_names.remove(trunk)
  84
  85         # Convert the reference names into Bazaar speak. If we haven't
  86         # already put the 'trunk' first, do it now.
  87         git_to_bzr_map = {}
  88         for ref_name in ref_names:
  89             git_to_bzr_map[ref_name] = self.cache_mgr.branch_mapper.git_to_bzr(ref_name)
  90         if ref_names and self.branch is None:
  91             trunk = self.select_trunk(ref_names)
  92             git_bzr_items = [(trunk, git_to_bzr_map[trunk])]
  93             del git_to_bzr_map[trunk]
  94         else:
  95             git_bzr_items = []
  96         git_bzr_items.extend(sorted(git_to_bzr_map.items(), key=itemgetter(1)))
  97
  98         # Policy for locating branches
  99         def dir_under_current(name, ref_name):
 100             # Using the Bazaar name, get a directory under the current one
 101             repo_base = self.repo.bzrdir.transport.base
 102             return osutils.pathjoin(repo_base, "..", name)
 103         def dir_sister_branch(name, ref_name):
 104             # Using the Bazaar name, get a sister directory to the branch
 105             return osutils.pathjoin(self.branch.base, "..", name)
 106         if self.branch is not None:
 107             dir_policy = dir_sister_branch
 108         else:
 109             dir_policy = dir_under_current
 110
 111         # Create/track missing branches
 112         shared_repo = self.repo.is_shared()
 113         for ref_name, name in git_bzr_items:
 114             tip = self.heads_by_ref[ref_name][0]
 115             if shared_repo:
 116                 location = dir_policy(name, ref_name)
 117                 try:
 118                     br = self.make_branch(location)
 119                     branch_tips.append((br,tip))
 120                     continue
 121                 except errors.BzrError, ex:
 122                     show_error("ERROR: failed to create branch %s: %s",
 123                         location, ex)
 124             lost_head = self.cache_mgr.lookup_committish(tip)
 125             lost_info = (name, lost_head)
 126             lost_heads.append(lost_info)
 127         return branch_tips, lost_heads
 128
 129     def select_trunk(self, ref_names):
 130         """Given a set of ref names, choose one as the trunk."""
 131         for candidate in ['refs/heads/master']:
 132             if candidate in ref_names:
 133                 return candidate
 134         # Use the last reference in the import stream
 135         return self.last_ref
 136
 137     def make_branch(self, location):
 138         """Make a branch in the repository if not already there."""
 139         to_transport = transport.get_transport(location)
 140         to_transport.create_prefix()
 141         try:
 142             return bzrdir.BzrDir.open(location).open_branch()
 143         except errors.NotBranchError, ex:
 144             return bzrdir.BzrDir.create_branch_convenience(location,
 145                 format=self._branch_format,
 146                 possible_transports=[to_transport])
 147
 148     def _update_branch(self, br, last_mark):
 149         """Update a branch with last revision and tag information.
 150
 151         :return: whether the branch was changed or not
 152         """
 153         last_rev_id = self.cache_mgr.lookup_committish(last_mark)
 154         self.repo.lock_read()
 155         try:
 156             graph = self.repo.get_graph()
 157             revno = graph.find_distance_to_null(last_rev_id, [])
 158         finally:
 159             self.repo.unlock()
 160         existing_revno, existing_last_rev_id = br.last_revision_info()
 161         changed = False
 162         if revno != existing_revno or last_rev_id != existing_last_rev_id:
 163             br.set_last_revision_info(revno, last_rev_id)
 164             changed = True
 165         # apply tags known in this branch
 166         my_tags = {}
 167         if self.tags:
 168             graph = self.repo.get_graph()
 169             ancestry = [r for (r, ps) in graph.iter_ancestry([last_rev_id]) if ps is not None]
 170             for tag,rev in self.tags.items():
 171                 if rev in ancestry:
 172                     my_tags[tag] = rev
 173             if my_tags:
 174                 br.tags._set_tag_dict(my_tags)
 175                 changed = True
 176         if changed:
 177             tagno = len(my_tags)
 178             note("\t branch %s now has %d %s and %d %s", br.nick,
 179                 revno, single_plural(revno, "revision", "revisions"),
 180                 tagno, single_plural(tagno, "tag", "tags"))
 181         return changed