libs/msm/doc/HTML/examples/BoostCon09Full.cpp
// Copyright 2010 Christophe Henry // henry UNDERSCORE christophe AT hotmail DOT com // This is an extended version of the state machine available in the boost::mpl library // Distributed under the same license as the original. // Copyright for the original version: // Copyright 2005 David Abrahams and Aleksey Gurtovoy. Distributed // under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) #include <vector> #include <iostream> #include <boost/mpl/vector/vector50.hpp> #include <boost/msm/back/state_machine.hpp> #include <boost/msm/front/state_machine_def.hpp> #include <boost/msm/back/tools.hpp> namespace msm = boost::msm; namespace mpl = boost::mpl; namespace // Concrete FSM implementation { // events struct play {}; struct end_pause {}; struct stop {}; struct pause {}; struct open_close {}; struct NextSong {}; // event which every other event can convert to struct AllSongsPlayed { template <class Event> AllSongsPlayed(Event const&){} }; struct PreviousSong {}; struct error_found {}; struct end_error {}; // Flags. Allow information about a property of the current state struct CDLoaded {}; struct FirstSongPlaying {}; // A "complicated" event type that carries some data. enum DiskTypeEnum { DISK_CD=0, DISK_DVD=1 }; struct cd_detected { cd_detected(DiskTypeEnum diskType): disc_type(diskType) {} DiskTypeEnum disc_type; }; // Concrete FSM implementation struct player_ : public msm::front::state_machine_def<player_> { // The list of FSM states struct Empty : public msm::front::state<> { typedef mpl::vector<play> deferred_events; // every (optional) entry/exit methods get the event packed as boost::any. Not useful very often. template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "entering: Empty" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "leaving: Empty" << std::endl;} }; struct Open : public msm::front::state<> { typedef mpl::vector1<CDLoaded> flag_list; typedef mpl::vector<play> deferred_events; template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "entering: Open" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "leaving: Open" << std::endl;} }; // a state needing a pointer to the containing state machine // and using for this the non-default policy // if policy used, set_sm_ptr is needed struct Stopped : public msm::front::state<default_base_state,msm::front::sm_ptr> { // when stopped, the CD is loaded typedef mpl::vector1<CDLoaded> flag_list; template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "entering: Stopped" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "leaving: Stopped" << std::endl;} void set_sm_ptr(player_* pl){m_player=pl;} player_* m_player; }; // the player state machine contains a state which is himself a state machine // it demonstrates Shallow History: if the state gets activated with end_pause // then it will remember the last active state and reactivate it // also possible: AlwaysHistory, the last active state will always be reactivated // or NoHistory, always restart from the initial state struct Playing_ : public msm::front::state_machine_def<Playing_> { // when playing, the CD is loaded and we are in either pause or playing (duh) typedef mpl::vector<CDLoaded> flag_list; template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "entering: Playing" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "leaving: Playing" << std::endl;} // The list of FSM states struct Song1 : public msm::front::state<> { typedef mpl::vector1<FirstSongPlaying> flag_list; template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "starting: First song" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "finishing: First Song" << std::endl;} }; struct Song2 : public msm::front::state<> { template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "starting: Second song" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "finishing: Second Song" << std::endl;} }; struct Song3 : public msm::front::state<> { template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "starting: Third song" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "finishing: Third Song" << std::endl;} }; struct CDFinished : public msm::front::exit_pseudo_state<AllSongsPlayed> { template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "entering: Playing::CDFinished" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "leaving: Playing::CDFinished" << std::endl;} }; // the initial state. Must be defined typedef Song1 initial_state; // transition actions void start_next_song(NextSong const&) { std::cout << "Playing::start_next_song\n"; } void start_prev_song(PreviousSong const&) { std::cout << "Playing::start_prev_song\n"; } void all_songs_played(NextSong const&) { std::cout << "Playing::all_songs_played\n"; } // guard conditions typedef Playing_ pl; // makes transition table cleaner // Transition table for Playing struct transition_table : mpl::vector< // Start Event Next Action Guard // +---------+---------------+------------+---------------------+----------------------+ a_row < Song1 , NextSong , Song2 , &pl::start_next_song >, a_row < Song2 , PreviousSong, Song1 , &pl::start_prev_song >, a_row < Song2 , NextSong , Song3 , &pl::start_next_song >, a_row < Song3 , PreviousSong, Song2 , &pl::start_prev_song >, a_row < Song3 , NextSong , CDFinished , &pl::all_songs_played > // +---------+---------------+---------+---------------------+----------------------+ > {}; // Replaces the default no-transition response. template <class FSM,class Event> void no_transition(Event const& e, FSM&,int state) { std::cout << "no transition from state " << state << " on event " << typeid(e).name() << std::endl; } }; typedef msm::back::state_machine<Playing_,msm::back::ShallowHistory<mpl::vector<end_pause> > > Playing; // the player state machine contains a state which is himself a state machine (2 of them, Playing and Paused) struct Paused : public msm::front::state<> { typedef mpl::vector<CDLoaded> flag_list; template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "entering: Paused" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "leaving: Paused" << std::endl;} }; struct AllOk : public msm::front::state<> { template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "starting: AllOk" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "finishing: AllOk" << std::endl;} }; struct ErrorMode : //public msm::front::terminate_state<> public msm::front::interrupt_state<end_error> { template <class Event,class FSM> void on_entry(Event const&,FSM& ) {std::cout << "starting: ErrorMode" << std::endl;} template <class Event,class FSM> void on_exit(Event const&,FSM& ) {std::cout << "finishing: ErrorMode" << std::endl;} }; // the initial state of the player SM. Must be defined typedef mpl::vector<Empty,AllOk> initial_state; // transition actions void start_playback(play const&) { std::cout << "player::start_playback\n"; } void open_drawer(open_close const&) { std::cout << "player::open_drawer\n"; } void close_drawer(open_close const&) { std::cout << "player::close_drawer\n"; } void store_cd_info(cd_detected const&) { std::cout << "player::store_cd_info\n"; // generate another event to test the queue //cd.m_player.process_event(play()); } void stop_playback(stop const&) { std::cout << "player::stop_playback\n"; } void end_playback (AllSongsPlayed const&) { std::cout << "player::end_playback\n"; } void pause_playback(pause const&) { std::cout << "player::pause_playback\n"; } void resume_playback(end_pause const&) { std::cout << "player::resume_playback\n"; } void stop_and_open(open_close const&) { std::cout << "player::stop_and_open\n"; } void stopped_again(stop const&){std::cout << "player::stopped_again\n";} void report_error(error_found const&) {std::cout << "player::report_error\n";} void report_end_error(end_error const&) {std::cout << "player::report_end_error\n";} // guard conditions bool good_disk_format(cd_detected const& evt) { // to test a guard condition, let's say we understand only CDs, not DVD if (evt.disc_type != DISK_CD) { std::cout << "wrong disk, sorry" << std::endl; return false; } return true; } typedef player_ p; // makes transition table cleaner // Transition table for player struct transition_table : mpl::vector< // Start Event Next Action Guard // +-------------+---------------+---------+---------------------+----------------------+ a_row < Stopped , play , Playing , &p::start_playback >, a_row < Stopped , open_close , Open , &p::open_drawer >, a_row < Stopped , stop , Stopped , &p::stopped_again >, // +-------------+---------------+---------+---------------------+----------------------+ a_row < Open , open_close , Empty , &p::close_drawer >, // +-------------+---------------+---------+---------------------+----------------------+ a_row < Empty , open_close , Open , &p::open_drawer >, row < Empty , cd_detected , Stopped , &p::store_cd_info ,&p::good_disk_format >, // +-------------+---------------+---------+---------------------+----------------------+ a_row < Playing , stop , Stopped , &p::stop_playback >, a_row < Playing , pause , Paused , &p::pause_playback >, a_row < Playing , open_close , Open , &p::stop_and_open >, a_row < Playing::exit_pt< Playing_::CDFinished> , AllSongsPlayed, Stopped , &p::end_playback >, // +-------------+---------------+---------+---------------------+----------------------+ a_row < Paused , end_pause , Playing , &p::resume_playback >, a_row < Paused , stop , Stopped , &p::stop_playback >, a_row < Paused , open_close , Open , &p::stop_and_open >, // +-------------+---------------+---------+---------------------+----------------------+ a_row < AllOk , error_found ,ErrorMode, &p::report_error >, a_row < ErrorMode ,end_error ,AllOk , &p::report_end_error > // +-------------+---------------+---------+---------------------+----------------------+ > {}; // Replaces the default no-transition response. template <class FSM,class Event> void no_transition(Event const& e, FSM&,int state) { std::cout << "no transition from state " << state << " on event " << typeid(e).name() << std::endl; } }; typedef msm::back::state_machine<player_> player; // // Testing utilities. // void pstate(player const& p) { typedef player::stt Stt; typedef msm::back::generate_state_set<Stt>::type all_states; static char const* state_names[mpl::size<all_states>::value]; // fill the names of the states defined in the state machine mpl::for_each<all_states,boost::msm::wrap<mpl::placeholders::_1> > (msm::back::fill_state_names<Stt>(state_names)); for (unsigned int i=0;i<player::nr_regions::value;++i) { std::cout << " -> " << state_names[p.current_state()[i]] << std::endl; } } void test() { player p; // needed to start the highest-level SM. This will call on_entry and mark the start of the SM p.start(); std::cout << "CDLoaded active:" << std::boolalpha << p.is_flag_active<CDLoaded>() << std::endl; //=> false (no CD yet) // test deferred event // deferred in Empty and Open, will be handled only after event cd_detected std::cout << "play is not handled in the current state but is marked as delayed" << std::endl; p.process_event(play()); pstate(p); std::cout << "cd_detected will cause play to be handled also" << std::endl; // will be rejected, wrong disk type p.process_event(cd_detected(DISK_DVD)); pstate(p); // will be accepted, wrong disk type p.process_event(cd_detected(DISK_CD)); pstate(p); std::cout << "FirstSong active:" << std::boolalpha << p.is_flag_active<FirstSongPlaying>() << std::endl; //=> true p.process_event(NextSong());pstate(p); // We are now in second song, Flag inactive std::cout << "FirstSong active:" << std::boolalpha << p.is_flag_active<FirstSongPlaying>() << std::endl;//=> false p.process_event(NextSong());pstate(p); // 2nd song active p.process_event(PreviousSong());pstate(p); // Pause p.process_event(pause()); pstate(p); // go back to Playing // but end_pause is an event activating the History // => keep the last active State (SecondSong) p.process_event(end_pause()); pstate(p); // force an exit by listening all the songs p.process_event(NextSong()); p.process_event(NextSong());pstate(p); std::cout << "CDLoaded active:" << std::boolalpha << p.is_flag_active<CDLoaded>() << std::endl;//=> true std::cout << "FirstSong active:" << std::boolalpha << p.is_flag_active<FirstSongPlaying>() << std::endl;//=> false // go back to Playing // but play is not leading to Shallow History => do not remember the last active State (SecondSong) // and activate again FirstSong and LightOn p.process_event(play()); pstate(p); p.process_event(error_found()); pstate(p); // try generating more events std::cout << "Trying to generate another event" << std::endl; // will not work, fsm is terminated or interrupted p.process_event(NextSong());pstate(p); std::cout << "Trying to end the error" << std::endl; // will work only if ErrorMode is interrupt state p.process_event(end_error());pstate(p); std::cout << "Trying to generate another event" << std::endl; // will work only if ErrorMode is interrupt state p.process_event(NextSong());pstate(p); // the states and events of the higher level FSM (player) typedef player::stt Stt; typedef msm::back::generate_state_set<Stt>::type simple_states; std::cout << "the state list:" << std::endl; mpl::for_each<simple_states,boost::msm::wrap<mpl::placeholders::_1> >(msm::back::display_type ()); std::cout << "the event list:" << std::endl; typedef msm::back::generate_event_set<Stt>::type event_list; mpl::for_each<event_list,boost::msm::wrap<mpl::placeholders::_1> >(msm::back::display_type ()); std::cout << std::endl; // the states and events recursively searched typedef msm::back::recursive_get_transition_table<player>::type recursive_stt; std::cout << "the state list (including sub-SMs):" << std::endl; typedef msm::back::generate_state_set<recursive_stt>::type all_states; mpl::for_each<all_states,boost::msm::wrap<mpl::placeholders::_1> >(msm::back::display_type ()); std::cout << "the event list (including sub-SMs):" << std::endl; typedef msm::back::generate_event_set<recursive_stt>::type all_events; mpl::for_each<all_events,boost::msm::wrap<mpl::placeholders::_1> >(msm::back::display_type ()); } } int main() { test(); return 0; }