1//
2// Copyright (C) 2010 The Android Open Source Project
3//
4// Licensed under the Apache License, Version 2.0 (the "License");
5// you may not use this file except in compliance with the License.
6// You may obtain a copy of the License at
7//
8//      http://www.apache.org/licenses/LICENSE-2.0
9//
10// Unless required by applicable law or agreed to in writing, software
11// distributed under the License is distributed on an "AS IS" BASIS,
12// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13// See the License for the specific language governing permissions and
14// limitations under the License.
15//
16
17#include "update_engine/payload_generator/topological_sort.h"
18
19#include <set>
20#include <vector>
21
22#include <base/logging.h>
23
24using std::set;
25using std::vector;
26
27namespace chromeos_update_engine {
28
29namespace {
30void TopologicalSortVisit(const Graph& graph,
31                          set<Vertex::Index>* visited_nodes,
32                          vector<Vertex::Index>* nodes,
33                          Vertex::Index node) {
34  if (visited_nodes->find(node) != visited_nodes->end())
35    return;
36
37  visited_nodes->insert(node);
38  // Visit all children.
39  for (Vertex::EdgeMap::const_iterator it = graph[node].out_edges.begin();
40       it != graph[node].out_edges.end(); ++it) {
41    TopologicalSortVisit(graph, visited_nodes, nodes, it->first);
42  }
43  // Visit this node.
44  nodes->push_back(node);
45}
46}  // namespace
47
48void TopologicalSort(const Graph& graph, vector<Vertex::Index>* out) {
49  set<Vertex::Index> visited_nodes;
50
51  for (Vertex::Index i = 0; i < graph.size(); i++) {
52    TopologicalSortVisit(graph, &visited_nodes, out, i);
53  }
54}
55
56}  // namespace chromeos_update_engine
57