3246.2.2
by Martin Pool
Fix up import of tsort |
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# Copyright (C) 2005, 2008 Canonical Ltd
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1887.1.1
by Adeodato Simó
Do not separate paragraphs in the copyright statement with blank lines, |
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#
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974.1.68
by Aaron Bentley
Added GPL notice |
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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1887.1.1
by Adeodato Simó
Do not separate paragraphs in the copyright statement with blank lines, |
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#
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974.1.68
by Aaron Bentley
Added GPL notice |
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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1887.1.1
by Adeodato Simó
Do not separate paragraphs in the copyright statement with blank lines, |
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#
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974.1.68
by Aaron Bentley
Added GPL notice |
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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4183.7.1
by Sabin Iacob
update FSF mailing address |
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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974.1.68
by Aaron Bentley
Added GPL notice |
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1594.2.15
by Robert Collins
Unfuck performance. |
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974.1.72
by Aaron Bentley
added all_descendants and node_distances, exception when root doesn't exist |
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def max_distance(node, ancestors, distances, root_descendants): |
3943.8.1
by Marius Kruger
remove all trailing whitespace from bzr source |
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"""Calculate the max distance to an ancestor.
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974.1.66
by Aaron Bentley
more cleanups, docs, sorting stuff |
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Return None if not all possible ancestors have known distances"""
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974.1.59
by aaron.bentley at utoronto
Created yet another longest-patch-picker |
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best = None |
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if node in distances: |
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best = distances[node] |
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for ancestor in ancestors[node]: |
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974.1.72
by Aaron Bentley
added all_descendants and node_distances, exception when root doesn't exist |
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# skip ancestors we will never traverse:
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if root_descendants is not None and ancestor not in root_descendants: |
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continue
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974.1.66
by Aaron Bentley
more cleanups, docs, sorting stuff |
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# An ancestor which is not listed in ancestors will never be in
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# distances, so we pretend it never existed.
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974.1.64
by Aaron Bentley
Handled ancestors that are missing when finding a base |
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if ancestor not in ancestors: |
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continue
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974.1.59
by aaron.bentley at utoronto
Created yet another longest-patch-picker |
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if ancestor not in distances: |
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return None |
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1185.8.3
by Aaron Bentley
Fixed bug in distance-from-root graph operation |
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if best is None or distances[ancestor]+1 > best: |
974.1.59
by aaron.bentley at utoronto
Created yet another longest-patch-picker |
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best = distances[ancestor] + 1 |
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return best |
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3943.8.1
by Marius Kruger
remove all trailing whitespace from bzr source |
38 |
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974.1.72
by Aaron Bentley
added all_descendants and node_distances, exception when root doesn't exist |
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def node_distances(graph, ancestors, start, root_descendants=None): |
974.1.66
by Aaron Bentley
more cleanups, docs, sorting stuff |
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"""Produce a list of nodes, sorted by distance from a start node.
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This is an algorithm devised by Aaron Bentley, because applying Dijkstra
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backwards seemed too complicated.
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For each node, we walk its descendants. If all the descendant's ancestors
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have a max-distance-to-start, (excluding ones that can never reach start),
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we calculate their max-distance-to-start, and schedule their descendants.
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So when a node's last parent acquires a distance, it will acquire a
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distance on the next iteration.
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Once we know the max distances for all nodes, we can return a list sorted
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by distance, farthest first.
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"""
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974.1.59
by aaron.bentley at utoronto
Created yet another longest-patch-picker |
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distances = {start: 0} |
974.1.60
by aaron.bentley at utoronto
Initial import of common-ancestor detection |
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lines = set([start]) |
974.1.59
by aaron.bentley at utoronto
Created yet another longest-patch-picker |
56 |
while len(lines) > 0: |
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new_lines = set() |
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for line in lines: |
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974.1.72
by Aaron Bentley
added all_descendants and node_distances, exception when root doesn't exist |
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line_descendants = graph[line] |
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for descendant in line_descendants: |
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distance = max_distance(descendant, ancestors, distances, |
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root_descendants) |
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974.1.59
by aaron.bentley at utoronto
Created yet another longest-patch-picker |
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if distance is None: |
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continue
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distances[descendant] = distance |
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new_lines.add(descendant) |
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lines = new_lines |
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974.1.72
by Aaron Bentley
added all_descendants and node_distances, exception when root doesn't exist |
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return distances |
974.1.59
by aaron.bentley at utoronto
Created yet another longest-patch-picker |
69 |
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974.1.87
by Aaron Bentley
Refactored and documented graph stuff |
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def nodes_by_distance(distances): |
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"""Return a list of nodes sorted by distance"""
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974.1.59
by aaron.bentley at utoronto
Created yet another longest-patch-picker |
72 |
def by_distance(n): |
974.1.66
by Aaron Bentley
more cleanups, docs, sorting stuff |
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return distances[n],n |
974.1.72
by Aaron Bentley
added all_descendants and node_distances, exception when root doesn't exist |
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974.1.59
by aaron.bentley at utoronto
Created yet another longest-patch-picker |
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node_list = distances.keys() |
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node_list.sort(key=by_distance, reverse=True) |
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return node_list |
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974.1.72
by Aaron Bentley
added all_descendants and node_distances, exception when root doesn't exist |
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974.1.87
by Aaron Bentley
Refactored and documented graph stuff |
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def select_farthest(distances, common): |
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"""Return the farthest common node, or None if no node qualifies."""
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node_list = nodes_by_distance(distances) |
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for node in node_list: |
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if node in common: |
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return node |
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974.1.72
by Aaron Bentley
added all_descendants and node_distances, exception when root doesn't exist |
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def all_descendants(descendants, start): |
974.1.87
by Aaron Bentley
Refactored and documented graph stuff |
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"""Produce a set of all descendants of the start node.
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The input is a map of node->list of descendants for a graph encompassing
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start.
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"""
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974.1.72
by Aaron Bentley
added all_descendants and node_distances, exception when root doesn't exist |
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result = set() |
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lines = set([start]) |
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while len(lines) > 0: |
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new_lines = set() |
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for line in lines: |
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if line not in descendants: |
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continue
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for descendant in descendants[line]: |
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if descendant in result: |
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continue
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result.add(descendant) |
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new_lines.add(descendant) |
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lines = new_lines |
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return result |
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1594.2.3
by Robert Collins
bugfix revision.MultipleRevisionSources.get_revision_graph to integrate ghosts between sources. [slow on weaves, fast on knits. |
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class Graph(object): |
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1759.2.2
by Jelmer Vernooij
Revert some of my spelling fixes and fix some typos after review by Aaron. |
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"""A graph object which can memoise and cache results for performance."""
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1594.2.3
by Robert Collins
bugfix revision.MultipleRevisionSources.get_revision_graph to integrate ghosts between sources. [slow on weaves, fast on knits. |
109 |
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def __init__(self): |
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super(Graph, self).__init__() |
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self.roots = set([]) |
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self.ghosts = set([]) |
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self._graph_ancestors = {} |
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self._graph_descendants = {} |
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def add_ghost(self, node_id): |
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"""Add a ghost to the graph."""
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self.ghosts.add(node_id) |
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self._ensure_descendant(node_id) |
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def add_node(self, node_id, parent_ids): |
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"""Add node_id to the graph with parent_ids as its parents."""
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2592.3.31
by Robert Collins
All GraphKnit based repository tests passing. |
124 |
if len(parent_ids) == 0: |
1594.2.3
by Robert Collins
bugfix revision.MultipleRevisionSources.get_revision_graph to integrate ghosts between sources. [slow on weaves, fast on knits. |
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self.roots.add(node_id) |
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self._graph_ancestors[node_id] = list(parent_ids) |
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self._ensure_descendant(node_id) |
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for parent in parent_ids: |
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self._ensure_descendant(parent) |
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self._graph_descendants[parent][node_id] = 1 |
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3943.8.1
by Marius Kruger
remove all trailing whitespace from bzr source |
131 |
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1594.2.3
by Robert Collins
bugfix revision.MultipleRevisionSources.get_revision_graph to integrate ghosts between sources. [slow on weaves, fast on knits. |
132 |
def _ensure_descendant(self, node_id): |
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"""Ensure that a descendant lookup for node_id will work."""
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if not node_id in self._graph_descendants: |
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self._graph_descendants[node_id] = {} |
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def get_ancestors(self): |
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"""Return a dictionary of graph node:ancestor_list entries."""
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return dict(self._graph_ancestors.items()) |
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2530.1.1
by Aaron Bentley
Make topological sorting optional for get_ancestry |
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def get_ancestry(self, node_id, topo_sorted=True): |
1594.2.15
by Robert Collins
Unfuck performance. |
142 |
"""Return the inclusive ancestors of node_id in topological order."""
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# maybe optimise this ?
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3246.2.2
by Martin Pool
Fix up import of tsort |
144 |
from bzrlib.tsort import topo_sort |
1594.2.15
by Robert Collins
Unfuck performance. |
145 |
result = {} |
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pending = set([node_id]) |
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while len(pending): |
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current = pending.pop() |
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parents = self._graph_ancestors[current] |
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parents = [parent for parent in parents if parent not in self.ghosts] |
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result[current] = parents |
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for parent in parents: |
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if parent not in result and parent not in pending: |
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pending.add(parent) |
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2530.1.1
by Aaron Bentley
Make topological sorting optional for get_ancestry |
155 |
if not topo_sorted: |
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return result.keys() |
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1594.2.15
by Robert Collins
Unfuck performance. |
157 |
return topo_sort(result.items()) |
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1594.2.3
by Robert Collins
bugfix revision.MultipleRevisionSources.get_revision_graph to integrate ghosts between sources. [slow on weaves, fast on knits. |
159 |
def get_descendants(self): |
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"""Return a dictionary of graph node:child_node:distance entries."""
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return dict(self._graph_descendants.items()) |