1 //=======================================================================
2 // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
3 // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
4 //
5 // Distributed under the Boost Software License, Version 1.0. (See
6 // accompanying file LICENSE_1_0.txt or copy at
7 // http://www.boost.org/LICENSE_1_0.txt)
8 //=======================================================================
9
10 // Some small modifications are done by Alexander Holler
11
12 /*
13
14 Paul Moore's request:
15
16 As an example of a practical problem which is not restricted to graph
17 "experts", consider file dependencies. It's basically graph construction,
18 plus topological sort, but it might make a nice "tutorial" example. Build a
19 dependency graph of files, then use the algorithms to do things like
20
21 1. Produce a full recompilation order (topological sort, by modified date)
22 2. Produce a "parallel" recompilation order (same as above, but group files
23 which can be built in parallel)
24 3. Change analysis (if I change file x, which others need recompiling)
25 4. Dependency changes (if I add a dependency between file x and file y, what
26 are the effects)
27
28 */
29
30 #include <boost/config.hpp> // put this first to suppress some VC++ warnings
31
32 #include <iostream>
33 #include <iterator>
34 #include <algorithm>
35 #include <time.h>
36
37 #include <boost/utility.hpp>
38 #include <boost/graph/adjacency_list.hpp>
39 #include <boost/graph/topological_sort.hpp>
40 #include <boost/graph/depth_first_search.hpp>
41 #include <boost/graph/dijkstra_shortest_paths.hpp>
42 #include <boost/graph/visitors.hpp>
43
44 using namespace std;
45 using namespace boost;
46
47 enum files_e { dax_h, yow_h, boz_h, zow_h, foo_cpp,
48 foo_o, bar_cpp, bar_o, libfoobar_a,
49 zig_cpp, zig_o, zag_cpp, zag_o,
50 libzigzag_a, killerapp, N };
51 const char* name[] = { "dax.h", "yow.h", "boz.h", "zow.h", "foo.cpp",
52 "foo.o", "bar.cpp", "bar.o", "libfoobar.a",
53 "zig.cpp", "zig.o", "zag.cpp", "zag.o",
54 "libzigzag.a", "killerapp" };
55
56
57 struct print_visitor : public bfs_visitor<> {
58 template <class Vertex, class Graph>
discover_vertexprint_visitor59 void discover_vertex(Vertex v, Graph&) {
60 cout << name[v] << " ";
61 }
62 };
63
64
65 struct cycle_detector : public dfs_visitor<>
66 {
cycle_detectorcycle_detector67 cycle_detector(bool& has_cycle)
68 : m_has_cycle(has_cycle) { }
69
70 template <class Edge, class Graph>
back_edgecycle_detector71 void back_edge(Edge, Graph&) { m_has_cycle = true; }
72 protected:
73 bool& m_has_cycle;
74 };
75
76
77
78
main(int,char * [])79 int main(int,char*[])
80 {
81
82 typedef pair<int,int> Edge;
83 Edge used_by[] = {
84 Edge(dax_h, foo_cpp), Edge(dax_h, bar_cpp), Edge(dax_h, yow_h),
85 Edge(yow_h, bar_cpp), Edge(yow_h, zag_cpp),
86 Edge(boz_h, bar_cpp), Edge(boz_h, zig_cpp), Edge(boz_h, zag_cpp),
87 Edge(zow_h, foo_cpp),
88 Edge(foo_cpp, foo_o),
89 Edge(foo_o, libfoobar_a),
90 Edge(bar_cpp, bar_o),
91 Edge(bar_o, libfoobar_a),
92 Edge(libfoobar_a, libzigzag_a),
93 Edge(zig_cpp, zig_o),
94 Edge(zig_o, libzigzag_a),
95 Edge(zag_cpp, zag_o),
96 Edge(zag_o, libzigzag_a),
97 Edge(libzigzag_a, killerapp)
98 };
99 const std::size_t nedges = sizeof(used_by)/sizeof(Edge);
100
101 typedef adjacency_list<vecS, vecS, bidirectionalS> Graph;
102 #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300
103 // VC++ can't handle the iterator constructor
104 Graph g(N);
105 for (std::size_t j = 0; j < nedges; ++j) {
106 graph_traits<Graph>::edge_descriptor e; bool inserted;
107 boost::tie(e, inserted) = add_edge(used_by[j].first, used_by[j].second, g);
108 }
109 #else
110 Graph g(used_by, used_by + nedges, N);
111 #endif
112 typedef graph_traits<Graph>::vertex_descriptor Vertex;
113
114 // Determine ordering for a full recompilation
115 // and the order with files that can be compiled in parallel
116 {
117 typedef list<Vertex> MakeOrder;
118 MakeOrder::iterator i;
119 MakeOrder make_order;
120
121 topological_sort(g, std::front_inserter(make_order));
122 cout << "make ordering: ";
123 for (i = make_order.begin();
124 i != make_order.end(); ++i)
125 cout << name[*i] << " ";
126
127 cout << endl << endl;
128
129 // Parallel compilation ordering
130 std::vector<int> time(N, 0);
131 for (i = make_order.begin(); i != make_order.end(); ++i) {
132 // Walk through the in_edges an calculate the maximum time.
133 if (in_degree (*i, g) > 0) {
134 Graph::in_edge_iterator j, j_end;
135 int maxdist=0;
136 // Through the order from topological sort, we are sure that every
137 // time we are using here is already initialized.
138 for (boost::tie(j, j_end) = in_edges(*i, g); j != j_end; ++j)
139 maxdist=(std::max)(time[source(*j, g)], maxdist);
140 time[*i]=maxdist+1;
141 }
142 }
143
144 cout << "parallel make ordering, " << endl
145 << "vertices with same group number can be made in parallel" << endl;
146 {
147 graph_traits<Graph>::vertex_iterator i, iend;
148 for (boost::tie(i,iend) = vertices(g); i != iend; ++i)
149 cout << "time_slot[" << name[*i] << "] = " << time[*i] << endl;
150 }
151
152 }
153 cout << endl;
154
155 // if I change yow.h what files need to be re-made?
156 {
157 cout << "A change to yow.h will cause what to be re-made?" << endl;
158 print_visitor vis;
159 breadth_first_search(g, vertex(yow_h, g), visitor(vis));
160 cout << endl;
161 }
162 cout << endl;
163
164 // are there any cycles in the graph?
165 {
166 bool has_cycle = false;
167 cycle_detector vis(has_cycle);
168 depth_first_search(g, visitor(vis));
169 cout << "The graph has a cycle? " << has_cycle << endl;
170 }
171 cout << endl;
172
173 // add a dependency going from bar.cpp to dax.h
174 {
175 cout << "adding edge bar_cpp -> dax_h" << endl;
176 add_edge(bar_cpp, dax_h, g);
177 }
178 cout << endl;
179
180 // are there any cycles in the graph?
181 {
182 bool has_cycle = false;
183 cycle_detector vis(has_cycle);
184 depth_first_search(g, visitor(vis));
185 cout << "The graph has a cycle now? " << has_cycle << endl;
186 }
187
188 return 0;
189 }
190