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