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Viewing changes to bzrlib/revision.py

  • Committer: Aaron Bentley
  • Date: 2005-08-25 22:05:37 UTC
  • mto: (1092.1.42) (1185.3.4)
  • mto: This revision was merged to the branch mainline in revision 1178.
  • Revision ID: abentley@panoramicfeedback.com-20050825220537-3a8e6ffc843ad8ca
Improved intermediate revision tracer
Now, when asked, it always finds the longest lines.
It maximizes the number of revision-history lines and, secondarily, minimizes
the number of non-revision-history lines.

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Lines of Context:
bzrlib/revision.py
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def get_intervening_revisions(ancestor_id, rev_id, rev_source, 
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                              revision_history=None):
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    """Find the longest line of descent from maybe_ancestor to revision.
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    Revision history is followed where possible
 
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    Revision history is followed where possible.
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    If ancestor_id == rev_id, list will be empty.
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    Otherwise, rev_id will be the last entry.  ancestor_id will never appear.
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    If ancestor_id is not an ancestor, NotAncestor will be thrown
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    """
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    # This lists only the first descendant we encounter
 
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    [rev_source.get_revision(r) for r in (ancestor_id, rev_id)]
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    if ancestor_id == rev_id:
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        return []
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    def in_history(myrev):
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        return revision_history is not None and myrev in revision_history
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    def remove_broken_lines(revisions, rev_id, descendant_map):
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        broken = set()
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        for revision in revisions:
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            cur_revision = revision
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            while cur_revision != rev_id:
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                cur_revision = descendant_map.get(cur_revision)
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                if cur_revision is None:
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                    broken.add(revision)
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                    break
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        return [r for r in revisions if r not in broken]
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    def trace_ancestry():
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        revisions = [rev_id]
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        descendant_map = {}
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        while len(revisions) > 0:
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            remove_broken = False
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            new_revisions = []
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            for revision in revisions:
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                parent_ids = [p.revision_id for p in 
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                              rev_source.get_revision(revision).parents]
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                for parent_id in parent_ids:
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                    if parent_id == ancestor_id:
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                        return revision, descendant_map
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                    if descendant_map.has_key(parent_id):
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                        if in_history(descendant_map[parent_id]):
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                            continue
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                        else:
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                            remove_broken = True
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                    descendant_map[parent_id] = revision
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                    new_revisions.append(parent_id)
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            if remove_broken:
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                new_revisions = remove_broken_lines(new_revisions, rev_id,
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                                                    descendant_map,)
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            revisions = new_revisions
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        raise Exception(revision, parent_ids)
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        return None, descendant_map
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    list_start, descendant_map = trace_ancestry()
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    if list_start is None:
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        raise Exception(descendant_map)
 
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    def historical_lines(line):
 
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        """Return a tuple of historical/non_historical lines, for sorting.
 
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        The non_historical count is negative, since non_historical lines are
 
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        a bad thing.
 
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        """
 
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        good_count = 0
 
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        bad_count = 0
 
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        for revision in line:
 
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            if revision in revision_history:
 
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                good_count += 1
 
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            else:
 
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                bad_count -= 1
 
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        return good_count, bad_count
 
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    active = [[rev_id]]
 
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    successful_lines = []
 
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    while len(active) > 0:
 
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        new_active = []
 
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        for line in active:
 
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            parent_ids = [p.revision_id for p in 
 
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                          rev_source.get_revision(line[-1]).parents]
 
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            for parent in parent_ids:
 
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                line_copy = line[:]
 
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                if parent == ancestor_id:
 
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                    successful_lines.append(line_copy)
 
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                else:
 
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                    line_copy.append(parent)
 
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                    new_active.append(line_copy)
 
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        active = new_active
 
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    if len(successful_lines) == 0:
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        raise bzrlib.errors.NotAncestor(rev_id, ancestor_id)
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    intermediate_revisions = [list_start]
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    next_revision = list_start
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    while next_revision != rev_id:
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        next_revision = descendant_map[next_revision]
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        intermediate_revisions.append(next_revision)
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    return intermediate_revisions
 
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    for line in successful_lines:
 
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        line.reverse()
 
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    if revision_history is not None:
 
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        by_historical_lines = []
 
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        for line in successful_lines:
 
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            count = historical_lines(line)
 
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            by_historical_lines.append((count, line))
 
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        by_historical_lines.sort()
 
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        if by_historical_lines[-1][0][0] > 0:
 
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            return by_historical_lines[-1][1]
 
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    assert len(successful_lines)
 
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    successful_lines.sort(cmp, len)
 
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    return successful_lines[-1]