libs/msm/doc/HTML/examples/TestInternal.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 <iostream> #include "boost/mpl/vector/vector30.hpp" // back-end #include <boost/msm/back/state_machine.hpp> //front-end #include <boost/msm/front/state_machine_def.hpp> #include <boost/msm/front/functor_row.hpp> #include <boost/msm/front/internal_row.hpp> namespace msm = boost::msm; namespace mpl = boost::mpl; using namespace msm::front; namespace { // events struct play {}; struct end_pause {}; struct stop {}; struct pause {}; struct internal_event {}; struct open_close {}; struct NextSong {}; struct PreviousSong {}; struct to_ignore {}; // A "complicated" event type that carries some data. enum DiskTypeEnum { DISK_CD=0, DISK_DVD=1 }; struct cd_detected { cd_detected(std::string name, DiskTypeEnum diskType) : name(name), disc_type(diskType) {} std::string name; DiskTypeEnum disc_type; }; // front-end: define the FSM structure struct player_ : public msm::front::state_machine_def<player_> { // 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"; } void stop_playback(stop const&) { std::cout << "player::stop_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";} // 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; } // transitions internal to Empty void internal_action(cd_detected const&){ std::cout << "Empty::internal action\n"; } bool internal_guard(cd_detected const&) { std::cout << "Empty::internal guard\n"; return false; } void internal_action(internal_event const&){ std::cout << "Playing::internal action\n"; } bool internal_guard(internal_event const&) { std::cout << "Playing::internal guard\n"; return false; } // The list of FSM states struct Empty : public msm::front::state<> { // every (optional) entry/exit methods get the event passed. 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 internal_guard_fct { template <class EVT,class FSM,class SourceState,class TargetState> bool operator()(EVT const& evt ,FSM&,SourceState& ,TargetState& ) { std::cout << "Empty::internal guard functor\n"; return false; } }; struct internal_action_fct { template <class EVT,class FSM,class SourceState,class TargetState> void operator()(EVT const& ,FSM& ,SourceState& ,TargetState& ) { std::cout << "Empty::internal action functor" << std::endl; } }; void internal_action(to_ignore const&) { std::cout << "Empty::(almost)ignoring event\n"; } // Transition table for Empty struct internal_transition_table : mpl::vector< // Start Event Next Action Guard Row < Empty , cd_detected , none , internal_action_fct ,internal_guard_fct >, Internal < cd_detected , internal_action_fct ,internal_guard_fct >, a_internal< to_ignore , Empty,&Empty::internal_action > // +---------+-------------+----------+------------------------+----------------------+ > {}; }; struct Open : public msm::front::state<> { 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;} }; struct Stopped : public msm::front::state<> { 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;} }; struct Playing_ : public msm::front::state_machine_def<Playing_> { // when playing, the CD is loaded and we are in either pause or playing (duh) 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<> { 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;} }; // the initial state. Must be defined typedef Song1 initial_state; // transition actions void start_next_song(NextSong const&){std::cout << "Playing: start_next_song" << std::endl;} void start_prev_song(PreviousSong const&){std::cout << "Playing: start_prev_song" << std::endl;} // guard conditions struct playing_internal_guard { template <class EVT,class FSM,class SourceState,class TargetState> bool operator()(EVT const& evt ,FSM&,SourceState& ,TargetState& ) { std::cout << "Playing::internal guard fct\n"; return true; } }; struct playing_false_guard { template <class EVT,class FSM,class SourceState,class TargetState> bool operator()(EVT const& evt ,FSM&,SourceState& ,TargetState& ) { std::cout << "Playing::false guard\n"; return false; } }; struct playing_internal_fct { template <class EVT,class FSM,class SourceState,class TargetState> void operator()(EVT const& evt ,FSM&,SourceState& ,TargetState& ) { std::cout << "Playing::internal fct\n"; } }; typedef Playing_ pl; // makes transition table cleaner // Transition table for Playing struct transition_table : mpl::vector4< // 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 > // +---------+-------------+---------+---------------------+----------------------+ > {}; // Internal transition table for Playing // +---------+----------------+---------+---------------------+-----------------------+ struct internal_transition_table : mpl::vector< // normal internal transition // Start Event Next Action Guard Internal < internal_event , playing_internal_fct,playing_internal_guard >, // conflict between internal and the external defined above Internal < PreviousSong , playing_internal_fct,playing_false_guard >, internal < internal_event , player_,&player_::internal_action, player_,&player_::internal_guard > // +---------+----------------+---------+---------------------+-----------------------+ > {}; // 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; } }; // back-end typedef msm::back::state_machine<Playing_> Playing; // state not defining any entry or exit struct Paused : public msm::front::state<> { }; // the initial state of the player SM. Must be defined typedef Empty initial_state; 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 >, _row < Stopped , stop , Stopped >, // +---------+-------------+---------+---------------------+----------------------+ a_row < Open , open_close , Empty , &p::close_drawer >, // +---------+-------------+---------+---------------------+----------------------+ a_row < Empty , open_close , Open , &p::open_drawer >, // conflict between a normal and 2 internal transitions (irow/g_irow) // + a state-defined internals defined 2 ways (see Empty) row < Empty , cd_detected , Stopped , &p::store_cd_info ,&p::good_disk_format >, irow < Empty , cd_detected , &p::internal_action ,&p::internal_guard >, g_irow < Empty , cd_detected ,&p::internal_guard >, // +---------+-------------+---------+---------------------+----------------------+ 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 < 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 > // +---------+-------------+---------+---------------------+----------------------+ > {}; // 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; } }; // Pick a back-end typedef msm::back::state_machine<player_> player; // // Testing utilities. // static char const* const state_names[] = { "Stopped", "Open", "Empty", "Playing", "Paused" }; void pstate(player const& p) { std::cout << " -> " << state_names[p.current_state()[0]] << 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(); // this event will be ignored and not call no_transition p.process_event(to_ignore()); // go to Open, call on_exit on Empty, then action, then on_entry on Open p.process_event(open_close()); pstate(p); p.process_event(open_close()); pstate(p); // will be rejected, wrong disk type p.process_event( cd_detected("louie, louie",DISK_DVD)); pstate(p); p.process_event( cd_detected("louie, louie",DISK_CD)); pstate(p); p.process_event(play()); p.process_event(NextSong()); std::cout << "sending an internal event" << std::endl; p.process_event(internal_event()); std::cout << "conflict between the internal and normal transition. Internal is tried last" << std::endl; p.process_event(PreviousSong()); // at this point, Play is active p.process_event(pause()); pstate(p); // go back to Playing p.process_event(end_pause()); pstate(p); p.process_event(pause()); pstate(p); p.process_event(stop()); pstate(p); // event leading to the same state // no action method called as it is not present in the transition table p.process_event(stop()); pstate(p); } } int main() { test(); return 0; }