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     )
  26
  27
  28 class BranchUpdater(object):
  29
  30     def __init__(self, repo, branch, cache_mgr, heads_by_ref, last_ref, tags):
  31         """Create an object responsible for updating branches.
  32
  33         :param heads_by_ref: a dictionary where
  34           names are git-style references like refs/heads/master;
  35           values are one item lists of commits marks.
  36         """
  37         self.repo = repo
  38         self.branch = branch
  39         self.cache_mgr = cache_mgr
  40         self.heads_by_ref = heads_by_ref
  41         self.last_ref = last_ref
  42         self.tags = tags
  43         self._branch_format = \
  44             best_format_for_objects_in_a_repository(repo)
  45
  46     def update(self):
  47         """Update the Bazaar branches and tips matching the heads.
  48
  49         If the repository is shared, this routine creates branches
  50         as required. If it isn't, warnings are produced about the
  51         lost of information.
  52
  53         :return: updated, lost_heads where
  54           updated = the list of branches updated ('trunk' is first)
  55           lost_heads = a list of (bazaar-name,revision) for branches that
  56             would have been created had the repository been shared
  57         """
  58         updated = []
  59         branch_tips, lost_heads = self._get_matching_branches()
  60         for br, tip in branch_tips:
  61             if self._update_branch(br, tip):
  62                 updated.append(br)
  63         return updated, lost_heads
  64
  65     def _get_matching_branches(self):
  66         """Get the Bazaar branches.
  67
  68         :return: branch_tips, lost_heads where
  69           branch_tips = a list of (branch,tip) tuples for branches. The
  70             first tip is the 'trunk'.
  71           lost_heads = a list of (bazaar-name,revision) for branches that
  72             would have been created had the repository been shared and
  73             everything succeeded
  74         """
  75         branch_tips = []
  76         lost_heads = []
  77         ref_names = self.heads_by_ref.keys()
  78         if self.branch is not None:
  79             trunk = self.select_trunk(ref_names)
  80             default_tip = self.heads_by_ref[trunk][0]
  81             branch_tips.append((self.branch, default_tip))
  82             ref_names.remove(trunk)
  83
  84         # Convert the reference names into Bazaar speak. If we haven't
  85         # already put the 'trunk' first, do it now.
  86         git_to_bzr_map = {}
  87         for ref_name in ref_names:
  88             git_to_bzr_map[ref_name] = self.cache_mgr.branch_mapper.git_to_bzr(ref_name)
  89         if ref_names and self.branch is None:
  90             trunk = self.select_trunk(ref_names)
  91             git_bzr_items = [(trunk, git_to_bzr_map[trunk])]
  92             del git_to_bzr_map[trunk]
  93         else:
  94             git_bzr_items = []
  95         git_bzr_items.extend(sorted(git_to_bzr_map.items(), key=itemgetter(1)))
  96
  97         # Policy for locating branches
  98         def dir_under_current(name, ref_name):
  99             # Using the Bazaar name, get a directory under the current one
 100             repo_base = self.repo.bzrdir.transport.base
 101             return osutils.pathjoin(repo_base, "..", name)
 102         def dir_sister_branch(name, ref_name):
 103             # Using the Bazaar name, get a sister directory to the branch
 104             return osutils.pathjoin(self.branch.base, "..", name)
 105         if self.branch is not None:
 106             dir_policy = dir_sister_branch
 107         else:
 108             dir_policy = dir_under_current
 109
 110         # Create/track missing branches
 111         shared_repo = self.repo.is_shared()
 112         for ref_name, name in git_bzr_items:
 113             tip = self.heads_by_ref[ref_name][0]
 114             if shared_repo:
 115                 location = dir_policy(name, ref_name)
 116                 try:
 117                     br = self.make_branch(location)
 118                     branch_tips.append((br,tip))
 119                     continue
 120                 except errors.BzrError, ex:
 121                     show_error("ERROR: failed to create branch %s: %s",
 122                         location, ex)
 123             lost_head = self.cache_mgr.lookup_committish(tip)
 124             lost_info = (name, lost_head)
 125             lost_heads.append(lost_info)
 126         return branch_tips, lost_heads
 127
 128     def select_trunk(self, ref_names):
 129         """Given a set of ref names, choose one as the trunk."""
 130         for candidate in ['refs/heads/master']:
 131             if candidate in ref_names:
 132                 return candidate
 133         # Use the last reference in the import stream
 134         return self.last_ref
 135
 136     def make_branch(self, location):
 137         """Make a branch in the repository if not already there."""
 138         to_transport = transport.get_transport(location)
 139         to_transport.create_prefix()
 140         try:
 141             return bzrdir.BzrDir.open(location).open_branch()
 142         except errors.NotBranchError, ex:
 143             return bzrdir.BzrDir.create_branch_convenience(location,
 144                 format=self._branch_format,
 145                 possible_transports=[to_transport])
 146
 147     def _update_branch(self, br, last_mark):
 148         """Update a branch with last revision and tag information.
 149
 150         :return: whether the branch was changed or not
 151         """
 152         from fastimport.helpers import single_plural
 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             ancestry = self.repo.get_ancestry(last_rev_id)
 169             for tag,rev in self.tags.items():
 170                 if rev in ancestry:
 171                     my_tags[tag] = rev
 172             if my_tags:
 173                 br.tags._set_tag_dict(my_tags)
 174                 changed = True
 175         if changed:
 176             tagno = len(my_tags)
 177             note("\t branch %s now has %d %s and %d %s", br.nick,
 178                 revno, single_plural(revno, "revision", "revisions"),
 179                 tagno, single_plural(tagno, "tag", "tags"))
 180         return changed