AU: Topological Sort.
Review URL: http://codereview.chromium.org/794003
diff --git a/topological_sort.cc b/topological_sort.cc
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+// Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "update_engine/topological_sort.h"
+#include <set>
+#include <vector>
+
+using std::set;
+using std::vector;
+
+namespace chromeos_update_engine {
+
+namespace {
+void TopologicalSortVisit(const Graph& graph,
+ set<Vertex::Index>* visited_nodes,
+ vector<Vertex::Index>* nodes,
+ Vertex::Index node) {
+ if (visited_nodes->find(node) != visited_nodes->end())
+ return;
+
+ visited_nodes->insert(node);
+ // Visit all children.
+ for (Vertex::EdgeMap::const_iterator it = graph[node].out_edges.begin();
+ it != graph[node].out_edges.end(); ++it) {
+ TopologicalSortVisit(graph, visited_nodes, nodes, it->first);
+ }
+ // Visit this node.
+ nodes->push_back(node);
+}
+} // namespace {}
+
+void TopologicalSort(const Graph& graph, vector<Vertex::Index>* out) {
+ set<Vertex::Index> visited_nodes;
+
+ for (Vertex::Index i = 0; i < graph.size(); i++) {
+ TopologicalSortVisit(graph, &visited_nodes, out, i);
+ }
+}
+
+} // namespace chromeos_update_engine