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1 // Copyright 2010 Christophe Henry
2 // henry UNDERSCORE christophe AT hotmail DOT com
3 // This is an extended version of the state machine available in the boost::mpl library
4 // Distributed under the same license as the original.
5 // Copyright for the original version:
6 // Copyright 2005 David Abrahams and Aleksey Gurtovoy. Distributed
7 // under the Boost Software License, Version 1.0. (See accompanying
8 // file LICENSE_1_0.txt or copy at
9 // http://www.boost.org/LICENSE_1_0.txt)
13 #include <boost/msm/back/state_machine.hpp>
15 #include <boost/msm/front/state_machine_def.hpp>
17 // include headers that implement a archive in simple text format
18 #include <boost/archive/text_oarchive.hpp>
19 #include <boost/archive/text_iarchive.hpp>
20 #include <boost/serialization/tracking.hpp>
24 namespace msm
= boost::msm
;
25 namespace mpl
= boost::mpl
;
36 struct PreviousSong
{};
38 // A "complicated" event type that carries some data.
41 cd_detected(std::string name
)
48 // front-end: define the FSM structure
49 struct player_
: public msm::front::state_machine_def
<player_
>
51 // The list of FSM states
52 struct Empty
: public msm::front::state
<>
54 // every (optional) entry/exit methods get the event passed
55 template <class Event
,class FSM
>
56 void on_entry(Event
const&,FSM
& ) {std::cout
<< "entering: Empty" << std::endl
;}
57 template <class Event
,class FSM
>
58 void on_exit(Event
const&,FSM
& ) {std::cout
<< "leaving: Empty" << std::endl
;}
60 struct Open
: public msm::front::state
<>
62 template <class Event
,class FSM
>
63 void on_entry(Event
const&,FSM
& ) {std::cout
<< "entering: Open" << std::endl
;}
64 template <class Event
,class FSM
>
65 void on_exit(Event
const&,FSM
& ) {std::cout
<< "leaving: Open" << std::endl
;}
68 struct Stopped
: public msm::front::state
<>
70 // when stopped, the CD is loaded
71 template <class Event
,class FSM
>
72 void on_entry(Event
const&,FSM
& ) {std::cout
<< "entering: Stopped" << std::endl
;}
73 template <class Event
,class FSM
>
74 void on_exit(Event
const&,FSM
& ) {std::cout
<< "leaving: Stopped" << std::endl
;}
77 struct Playing_
: public msm::front::state_machine_def
<Playing_
>
79 // when playing, the CD is loaded and we are in either pause or playing (duh)
80 template <class Event
,class FSM
>
81 void on_entry(Event
const&,FSM
& ) {std::cout
<< "entering: Playing" << std::endl
;}
82 template <class Event
,class FSM
>
83 void on_exit(Event
const&,FSM
& ) {std::cout
<< "leaving: Playing" << std::endl
;}
85 // The list of FSM states
86 struct Song1
: public msm::front::state
<>
88 template <class Event
,class FSM
>
89 void on_entry(Event
const&,FSM
& ) {std::cout
<< "starting: First song" << std::endl
;}
90 template <class Event
,class FSM
>
91 void on_exit(Event
const&,FSM
& ) {std::cout
<< "finishing: First Song" << std::endl
;}
93 struct Song2
: public msm::front::state
<>
95 template <class Event
,class FSM
>
96 void on_entry(Event
const&,FSM
& ) {std::cout
<< "starting: Second song" << std::endl
;}
97 template <class Event
,class FSM
>
98 void on_exit(Event
const&,FSM
& ) {std::cout
<< "finishing: Second Song" << std::endl
;}
100 struct Song3
: public msm::front::state
<>
102 template <class Event
,class FSM
>
103 void on_entry(Event
const&,FSM
& ) {std::cout
<< "starting: Third song" << std::endl
;}
104 template <class Event
,class FSM
>
105 void on_exit(Event
const&,FSM
& ) {std::cout
<< "finishing: Third Song" << std::endl
;}
107 // the initial state. Must be defined
108 typedef Song1 initial_state
;
109 // transition actions
110 void start_next_song(NextSong
const&) { std::cout
<< "Playing::start_next_song\n"; }
111 void start_prev_song(PreviousSong
const&) { std::cout
<< "Playing::start_prev_song\n"; }
114 typedef Playing_ pl
; // makes transition table cleaner
115 // Transition table for Playing
116 struct transition_table
: mpl::vector4
<
117 // Start Event Next Action Guard
118 // +---------+-------------+---------+---------------------+----------------------+
119 a_row
< Song1
, NextSong
, Song2
, &pl::start_next_song
>,
120 a_row
< Song2
, PreviousSong
, Song1
, &pl::start_prev_song
>,
121 a_row
< Song2
, NextSong
, Song3
, &pl::start_next_song
>,
122 a_row
< Song3
, PreviousSong
, Song2
, &pl::start_prev_song
>
123 // +---------+-------------+---------+---------------------+----------------------+
125 // Replaces the default no-transition response.
126 template <class FSM
,class Event
>
127 void no_transition(Event
const& e
, FSM
&,int state
)
129 std::cout
<< "no transition from state " << state
130 << " on event " << typeid(e
).name() << std::endl
;
135 // demonstrates Shallow History: if the state gets activated with end_pause
136 // then it will remember the last active state and reactivate it
137 // also possible: AlwaysHistory, the last active state will always be reactivated
138 // or NoHistory, always restart from the initial state
139 typedef msm::back::state_machine
<Playing_
,msm::back::ShallowHistory
<mpl::vector
<end_pause
> > > Playing
;
141 // state not defining any entry or exit
142 struct Paused
: public msm::front::state
<>
144 template <class Event
,class FSM
>
145 void on_entry(Event
const&,FSM
& ) {std::cout
<< "entering: Paused" << std::endl
;}
146 template <class Event
,class FSM
>
147 void on_exit(Event
const&,FSM
& ) {std::cout
<< "leaving: Paused" << std::endl
;}
150 // the initial state of the player SM. Must be defined
151 typedef Empty initial_state
;
153 // transition actions
154 void start_playback(play
const&) { std::cout
<< "player::start_playback\n"; }
155 void open_drawer(open_close
const&) { std::cout
<< "player::open_drawer\n"; }
156 void close_drawer(open_close
const&) { std::cout
<< "player::close_drawer\n"; }
157 void store_cd_info(cd_detected
const& cd
) {std::cout
<< "player::store_cd_info\n";}
158 void stop_playback(stop
const&) { std::cout
<< "player::stop_playback\n"; }
159 void pause_playback(pause
const&) { std::cout
<< "player::pause_playback\n"; }
160 void resume_playback(end_pause
const&) { std::cout
<< "player::resume_playback\n"; }
161 void stop_and_open(open_close
const&) { std::cout
<< "player::stop_and_open\n"; }
162 void stopped_again(stop
const&){std::cout
<< "player::stopped_again\n";}
165 typedef player_ p
; // makes transition table cleaner
167 // Transition table for player
168 struct transition_table
: mpl::vector
<
169 // Start Event Next Action Guard
170 // +---------+-------------+---------+---------------------+----------------------+
171 a_row
< Stopped
, play
, Playing
, &p::start_playback
>,
172 a_row
< Stopped
, open_close
, Open
, &p::open_drawer
>,
173 a_row
< Stopped
, stop
, Stopped
, &p::stopped_again
>,
174 // +---------+-------------+---------+---------------------+----------------------+
175 a_row
< Open
, open_close
, Empty
, &p::close_drawer
>,
176 // +---------+-------------+---------+---------------------+----------------------+
177 a_row
< Empty
, open_close
, Open
, &p::open_drawer
>,
178 a_row
< Empty
, cd_detected
, Stopped
, &p::store_cd_info
>,
179 // +---------+-------------+---------+---------------------+----------------------+
180 a_row
< Playing
, stop
, Stopped
, &p::stop_playback
>,
181 a_row
< Playing
, pause
, Paused
, &p::pause_playback
>,
182 a_row
< Playing
, open_close
, Open
, &p::stop_and_open
>,
183 // +---------+-------------+---------+---------------------+----------------------+
184 a_row
< Paused
, end_pause
, Playing
, &p::resume_playback
>,
185 a_row
< Paused
, stop
, Stopped
, &p::stop_playback
>,
186 a_row
< Paused
, open_close
, Open
, &p::stop_and_open
>
187 // +---------+-------------+---------+---------------------+----------------------+
190 // Replaces the default no-transition response.
191 template <class FSM
,class Event
>
192 void no_transition(Event
const& e
, FSM
&,int state
)
194 std::cout
<< "no transition from state " << state
195 << " on event " << typeid(e
).name() << std::endl
;
200 typedef msm::back::state_machine
<player_
> player
;
203 // Testing utilities.
205 static char const* const state_names
[] = { "Stopped", "Open", "Empty", "Playing", "Paused" };
207 void pstate(player
const& p
)
209 std::cout
<< " -> " << state_names
[p
.current_state()[0]] << std::endl
;
216 // needed to start the highest-level SM. This will call on_entry and mark the start of the SM
218 // go to Open, call on_exit on Empty, then action, then on_entry on Open
219 p
.process_event(open_close()); pstate(p
);
220 p
.process_event(open_close()); pstate(p
);
221 p
.process_event(cd_detected("louie, louie"));
222 p
.process_event(play());
224 // at this point, Play is active
225 // make transition happen inside it. Player has no idea about this event but it's ok.
226 p
.process_event(NextSong());pstate(p
); //2nd song active
227 p
.process_event(NextSong());pstate(p
);//3rd song active
228 p
.process_event(PreviousSong());pstate(p
);//2nd song active
229 p
.process_event(pause()); pstate(p
);
230 std::ofstream
ofs("fsm.txt");
231 // save fsm to archive (current state is Pause, Playing is in Song2)
233 boost::archive::text_oarchive
oa(ofs
);
234 // write class instance to archive
237 // reload fsm in state Open
240 // create and open an archive for input
241 std::ifstream
ifs("fsm.txt");
242 boost::archive::text_iarchive
ia(ifs
);
243 // read class state from archive
246 // go back to Playing
247 // as you see, remembers the original state as end_pause is an history trigger
248 p2
.process_event(end_pause()); pstate(p2
);
249 p2
.process_event(pause()); pstate(p2
);
250 p2
.process_event(stop()); pstate(p2
);
251 // event leading to the same state
252 p2
.process_event(stop()); pstate(p2
);
253 // play does not trigger shallow history => start back from 1st song
254 p2
.process_event(play()); pstate(p2
);
257 // eliminate object tracking (even if serialized through a pointer)
258 // at the risk of a programming error creating duplicate objects.
259 // this is to get rid of warning because p is not const
260 BOOST_CLASS_TRACKING(player
, boost::serialization::track_never
)