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Viewing changes to bzrlib/revision.py

  • Committer: aaron.bentley at utoronto
  • Date: 2005-08-21 04:15:04 UTC
  • mto: (1092.1.41) (1185.3.4)
  • mto: This revision was merged to the branch mainline in revision 1110.
  • Revision ID: aaron.bentley@utoronto.ca-20050821041504-866f53c120065af3
Added revision-based common-ancestor checking

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bzrlib/revision.py
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    behaves like Branch's.
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    """
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    for ancestor_id, distance in iter_ancestors(revision_id, revision_source):
 
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        if ancestor_id == candidate_id:
 
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            return True
 
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    return False
 
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def iter_ancestors(revision_id, revision_source, only_present=False):
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    ancestors = (revision_id,)
 
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    distance = 0
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    while len(ancestors) > 0:
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        new_ancestors = []
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        for ancestor in ancestors:
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            if ancestor == candidate_id:
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                return True
 
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            if not only_present:
 
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                yield ancestor, distance
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            try:
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                revision = revision_source.get_revision(ancestor)
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            except bzrlib.errors.NoSuchRevision, e:
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                    raise 
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                else:
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                    continue
 
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            if only_present:
 
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                yield ancestor, distance
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            new_ancestors.extend([p.revision_id for p in revision.parents])
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        ancestors = new_ancestors
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        distance += 1
 
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def find_present_ancestors(revision_id, revision_source):
 
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    found_ancestors = {}
 
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    count = 0
 
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    anc_iter = enumerate(iter_ancestors(revision_id, revision_source,
 
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                         only_present=True))
 
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    for anc_order, (anc_id, anc_distance) in anc_iter:
 
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        if not found_ancestors.has_key(anc_id):
 
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            found_ancestors[anc_id] = (anc_order, anc_distance)
 
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    return found_ancestors
 
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class AmbiguousBase(bzrlib.errors.BzrError):
 
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    def __init__(self, bases):
 
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        msg = "The correct base is unclear, becase %s are all equally close" %\
 
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            ", ".join(bases)
 
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        bzrlib.errors.BzrError.__init__(self, msg)
 
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        self.bases = bases
 
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def common_ancestor(revision_a, revision_b, revision_source):
 
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    """Find the ancestor common to both revisions that is closest to both.
 
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    """
 
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    from bzrlib.trace import mutter
 
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    a_ancestors = find_present_ancestors(revision_a, revision_source)
 
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    b_ancestors = find_present_ancestors(revision_b, revision_source)
 
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    a_intersection = []
 
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    b_intersection = []
 
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    # a_order is used as a tie-breaker when two equally-good bases are found
 
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    for revision, (a_order, a_distance) in a_ancestors.iteritems():
 
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        if b_ancestors.has_key(revision):
 
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            a_intersection.append((a_distance, a_order, revision))
 
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            b_intersection.append((b_ancestors[revision][1], a_order, revision))
 
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    mutter("a intersection: %r" % a_intersection)
 
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    mutter("b intersection: %r" % b_intersection)
 
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    def get_closest(intersection):
 
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        intersection.sort()
 
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        matches = [] 
 
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        for entry in intersection:
 
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            if entry[0] == intersection[0][0]:
 
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                matches.append(entry[2])
 
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        return matches
 
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    a_closest = get_closest(a_intersection)
 
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    if len(a_closest) == 0:
 
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        return None
 
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    b_closest = get_closest(b_intersection)
 
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    assert len(b_closest) != 0
 
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    mutter ("a_closest %r" % a_closest)
 
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    mutter ("b_closest %r" % b_closest)
 
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    if a_closest[0] in b_closest:
 
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        return a_closest[0]
 
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    elif b_closest[0] in a_closest:
 
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        return b_closest[0]
 
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    else:
 
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        raise AmbiguousBase((a_closest[0], b_closest[0]))
 
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    return a_closest[0]
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class MultipleRevisionSources(object):
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    def __init__(self, *args):