AU: Topological Sort.

src/platform/update_engine/topological_sort.cc

Index: src/platform/update_engine/topological_sort.cc
diff --git a/src/platform/update_engine/topological_sort.cc b/src/platform/update_engine/topological_sort.cc
new file mode 100644
index 0000000000000000000000000000000000000000..68de56b06214f51015ce509433f14e71a1ecc0d4
--- /dev/null
+++ b/src/platform/update_engine/topological_sort.cc
@@ -0,0 +1,39 @@
+// 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 {
+
+void TopologicalSortVisit(const Graph& graph,

[Daniel Erat, 2010/03/11 01:31:49]

make this function static

[adlr, 2010/03/11 04:12:08]

did namespace {}

+                          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);
+}
+
+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