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1 | #include <iostream> |
2 | // back-end | |
3 | #include <boost/msm/back/state_machine.hpp> | |
4 | //front-end | |
5 | #include <boost/msm/front/state_machine_def.hpp> | |
6 | ||
7 | // include headers that implement a archive in simple text format | |
8 | #include <boost/archive/text_oarchive.hpp> | |
9 | #include <boost/archive/text_iarchive.hpp> | |
10 | #include <boost/serialization/tracking.hpp> | |
11 | ||
12 | #include <fstream> | |
13 | ||
14 | ||
15 | namespace msm = boost::msm; | |
16 | namespace mpl = boost::mpl; | |
17 | ||
18 | ||
19 | namespace | |
20 | { | |
21 | // events | |
22 | struct play {}; | |
23 | struct end_pause {}; | |
24 | struct stop {}; | |
25 | struct pause {}; | |
26 | struct open_close {}; | |
27 | ||
28 | // A "complicated" event type that carries some data. | |
29 | enum DiskTypeEnum | |
30 | { | |
31 | DISK_CD=0, | |
32 | DISK_DVD=1 | |
33 | }; | |
34 | struct cd_detected | |
35 | { | |
36 | cd_detected(std::string name, DiskTypeEnum diskType) | |
37 | : name(name), | |
38 | disc_type(diskType) | |
39 | {} | |
40 | ||
41 | std::string name; | |
42 | DiskTypeEnum disc_type; | |
43 | }; | |
44 | ||
45 | // front-end: define the FSM structure | |
46 | struct player_ : public msm::front::state_machine_def<player_> | |
47 | { | |
48 | //we might want to serialize some data contained by the front-end | |
49 | int front_end_data; | |
50 | player_():front_end_data(0){} | |
51 | // to achieve this, ask for it | |
52 | typedef int do_serialize; | |
53 | // and provide a serialize | |
54 | template<class Archive> | |
55 | void serialize(Archive & ar, const unsigned int ) | |
56 | { | |
57 | ar & front_end_data; | |
58 | } | |
59 | // The list of FSM states | |
60 | struct Empty : public msm::front::state<> | |
61 | { | |
62 | // we want Empty to be serialized | |
63 | typedef int do_serialize; | |
64 | template<class Archive> | |
65 | void serialize(Archive & ar, const unsigned int ) | |
66 | { | |
67 | ar & some_dummy_data; | |
68 | } | |
69 | Empty():some_dummy_data(0){} | |
70 | // every (optional) entry/exit methods get the event passed. | |
71 | template <class Event,class FSM> | |
72 | void on_entry(Event const&,FSM& ) {std::cout << "entering: Empty" << std::endl;} | |
73 | template <class Event,class FSM> | |
74 | void on_exit(Event const&,FSM& ) {std::cout << "leaving: Empty" << std::endl;} | |
75 | int some_dummy_data; | |
76 | }; | |
77 | struct Open : public msm::front::state<> | |
78 | { | |
79 | template <class Event,class FSM> | |
80 | void on_entry(Event const& ,FSM&) {std::cout << "entering: Open" << std::endl;} | |
81 | template <class Event,class FSM> | |
82 | void on_exit(Event const&,FSM& ) {std::cout << "leaving: Open" << std::endl;} | |
83 | }; | |
84 | ||
85 | // sm_ptr still supported but deprecated as functors are a much better way to do the same thing | |
86 | struct Stopped : public msm::front::state<msm::front::default_base_state,msm::front::sm_ptr> | |
87 | { | |
88 | template <class Event,class FSM> | |
89 | void on_entry(Event const& ,FSM&) {std::cout << "entering: Stopped" << std::endl;} | |
90 | template <class Event,class FSM> | |
91 | void on_exit(Event const&,FSM& ) {std::cout << "leaving: Stopped" << std::endl;} | |
92 | void set_sm_ptr(player_* pl) | |
93 | { | |
94 | m_player=pl; | |
95 | } | |
96 | player_* m_player; | |
97 | }; | |
98 | ||
99 | struct Playing : public msm::front::state<> | |
100 | { | |
101 | template <class Event,class FSM> | |
102 | void on_entry(Event const&,FSM& ) {std::cout << "entering: Playing" << std::endl;} | |
103 | template <class Event,class FSM> | |
104 | void on_exit(Event const&,FSM& ) {std::cout << "leaving: Playing" << std::endl;} | |
105 | }; | |
106 | ||
107 | // state not defining any entry or exit | |
108 | struct Paused : public msm::front::state<> | |
109 | { | |
110 | }; | |
111 | ||
112 | // the initial state of the player SM. Must be defined | |
113 | typedef Empty initial_state; | |
114 | ||
115 | // transition actions | |
116 | void start_playback(play const&) { std::cout << "player::start_playback\n"; } | |
117 | void open_drawer(open_close const&) { std::cout << "player::open_drawer\n"; } | |
118 | void close_drawer(open_close const&) { std::cout << "player::close_drawer\n"; } | |
119 | void store_cd_info(cd_detected const&) { std::cout << "player::store_cd_info\n"; } | |
120 | void stop_playback(stop const&) { std::cout << "player::stop_playback\n"; } | |
121 | void pause_playback(pause const&) { std::cout << "player::pause_playback\n"; } | |
122 | void resume_playback(end_pause const&) { std::cout << "player::resume_playback\n"; } | |
123 | void stop_and_open(open_close const&) { std::cout << "player::stop_and_open\n"; } | |
124 | void stopped_again(stop const&) {std::cout << "player::stopped_again\n";} | |
125 | // guard conditions | |
126 | bool good_disk_format(cd_detected const& evt) | |
127 | { | |
128 | // to test a guard condition, let's say we understand only CDs, not DVD | |
129 | if (evt.disc_type != DISK_CD) | |
130 | { | |
131 | std::cout << "wrong disk, sorry" << std::endl; | |
132 | return false; | |
133 | } | |
134 | return true; | |
135 | } | |
136 | // used to show a transition conflict. This guard will simply deactivate one transition and thus | |
137 | // solve the conflict | |
138 | bool auto_start(cd_detected const&) | |
139 | { | |
140 | return false; | |
141 | } | |
142 | ||
143 | typedef player_ p; // makes transition table cleaner | |
144 | ||
145 | // Transition table for player | |
146 | struct transition_table : mpl::vector< | |
147 | // Start Event Next Action Guard | |
148 | // +---------+-------------+---------+---------------------+----------------------+ | |
149 | a_row < Stopped , play , Playing , &p::start_playback >, | |
150 | a_row < Stopped , open_close , Open , &p::open_drawer >, | |
151 | _row < Stopped , stop , Stopped >, | |
152 | // +---------+-------------+---------+---------------------+----------------------+ | |
153 | a_row < Open , open_close , Empty , &p::close_drawer >, | |
154 | // +---------+-------------+---------+---------------------+----------------------+ | |
155 | a_row < Empty , open_close , Open , &p::open_drawer >, | |
156 | row < Empty , cd_detected , Stopped , &p::store_cd_info ,&p::good_disk_format >, | |
157 | row < Empty , cd_detected , Playing , &p::store_cd_info ,&p::auto_start >, | |
158 | // +---------+-------------+---------+---------------------+----------------------+ | |
159 | a_row < Playing , stop , Stopped , &p::stop_playback >, | |
160 | a_row < Playing , pause , Paused , &p::pause_playback >, | |
161 | a_row < Playing , open_close , Open , &p::stop_and_open >, | |
162 | // +---------+-------------+---------+---------------------+----------------------+ | |
163 | a_row < Paused , end_pause , Playing , &p::resume_playback >, | |
164 | a_row < Paused , stop , Stopped , &p::stop_playback >, | |
165 | a_row < Paused , open_close , Open , &p::stop_and_open > | |
166 | // +---------+-------------+---------+---------------------+----------------------+ | |
167 | > {}; | |
168 | // Replaces the default no-transition response. | |
169 | template <class FSM,class Event> | |
170 | void no_transition(Event const& e, FSM&,int state) | |
171 | { | |
172 | std::cout << "no transition from state " << state | |
173 | << " on event " << typeid(e).name() << std::endl; | |
174 | } | |
175 | }; | |
176 | // Pick a back-end | |
177 | typedef msm::back::state_machine<player_> player; | |
178 | ||
179 | // | |
180 | // Testing utilities. | |
181 | // | |
182 | static char const* const state_names[] = { "Stopped", "Open", "Empty", "Playing", "Paused" }; | |
183 | void pstate(player const& p) | |
184 | { | |
185 | std::cout << " -> " << state_names[p.current_state()[0]] << std::endl; | |
186 | } | |
187 | ||
188 | void test() | |
189 | { | |
190 | player p; | |
191 | // needed to start the highest-level SM. This will call on_entry and mark the start of the SM | |
192 | p.start(); | |
193 | p.get_state<player_::Empty&>().some_dummy_data=3; | |
194 | p.front_end_data=4; | |
195 | ||
196 | // go to Open, call on_exit on Empty, then action, then on_entry on Open | |
197 | p.process_event(open_close()); pstate(p); | |
198 | ||
199 | std::ofstream ofs("fsm.txt"); | |
200 | // save fsm to archive (current state is Open) | |
201 | { | |
202 | boost::archive::text_oarchive oa(ofs); | |
203 | // write class instance to archive | |
204 | oa << p; | |
205 | } | |
206 | // reload fsm in state Open | |
207 | player p2; | |
208 | { | |
209 | // create and open an archive for input | |
210 | std::ifstream ifs("fsm.txt"); | |
211 | boost::archive::text_iarchive ia(ifs); | |
212 | // read class state from archive | |
213 | ia >> p2; | |
214 | } | |
215 | // we now use p2 as it was loaded | |
216 | // check that we kept Empty's data value | |
217 | std::cout << "Empty's data should be 3:" << p2.get_state<player_::Empty&>().some_dummy_data << std::endl; | |
218 | std::cout << "front-end data should be 4:" << p2.front_end_data << std::endl; | |
219 | ||
220 | p2.process_event(open_close()); pstate(p2); | |
221 | // will be rejected, wrong disk type | |
222 | p2.process_event( | |
223 | cd_detected("louie, louie",DISK_DVD)); pstate(p2); | |
224 | p2.process_event( | |
225 | cd_detected("louie, louie",DISK_CD)); pstate(p2); | |
226 | p2.process_event(play()); | |
227 | ||
228 | // at this point, Play is active | |
229 | p2.process_event(pause()); pstate(p2); | |
230 | // go back to Playing | |
231 | p2.process_event(end_pause()); pstate(p2); | |
232 | p2.process_event(pause()); pstate(p2); | |
233 | p2.process_event(stop()); pstate(p2); | |
234 | // event leading to the same state | |
235 | // no action method called as it is not present in the transition table | |
236 | p2.process_event(stop()); pstate(p2); | |
237 | } | |
238 | } | |
239 | // eliminate object tracking (even if serialized through a pointer) | |
240 | // at the risk of a programming error creating duplicate objects. | |
241 | // this is to get rid of warning because p is not const | |
242 | BOOST_CLASS_TRACKING(player, boost::serialization::track_never) | |
243 | ||
244 | int main() | |
245 | { | |
246 | test(); | |
247 | return 0; | |
248 | } |