// 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 <string>
#include "boost/mpl/vector/vector30.hpp"
#include <boost/msm/back/state_machine.hpp>
#include <boost/msm/front/state_machine_def.hpp>
#include <boost/msm/back/tools.hpp>
using namespace std;
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 {};
struct PreviousSong {};
struct ThreeSec {};
struct TenSec {};
struct error_found {};
struct end_error {};
struct cd_detected {};
// a simple visitor
struct SomeVisitor
{
template <class T>
void visit_state(T* astate,int i)
{
std::cout << "visiting state:" << typeid(*astate).name()
<< " with data:" << i << std::endl;
}
};
// base state for all states of ths fsm, to make them visitable
struct my_visitable_state
{
// signature of the accept function
typedef msm::back::args<void,SomeVisitor&,int> accept_sig;
// we also want polymorphic states
virtual ~my_visitable_state() {}
// default implementation for states who do not need to be visited
void accept(SomeVisitor&,int) const {}
// or if you want all states to be visited, provide an implementation
/*
void accept(SomeVisitor& vis,int i) const
{
vis.visit_state(this,i);
}
*/
};
// Concrete FSM implementation
struct player_ : public msm::front::state_machine_def<player_,my_visitable_state>
{
template <class Event,class FSM>
void on_entry(Event const&,FSM& ) {std::cout << "starting: player" << std::endl;}
// The list of FSM states
struct Empty : public msm::front::state<my_visitable_state>
{
typedef mpl::vector<play> deferred_events;
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;}
// this state wants to be visited
void accept(SomeVisitor& vis,int i) const
{
vis.visit_state(this,i);
}
};
struct Open : public msm::front::state<my_visitable_state>
{
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;}
// this state wants to be visited
void accept(SomeVisitor& vis,int i) const
{
vis.visit_state(this,i);
}
};
struct Stopped : public msm::front::state<my_visitable_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;}
// this state wants to be visited
void accept(SomeVisitor& vis,int i) const
{
// note that visiting will recursively visit sub-states
vis.visit_state(this,i);
}
};
struct Playing_ : public msm::front::state_machine_def<Playing_,my_visitable_state >
{
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;}
void accept(SomeVisitor& vis,int i) const
{
// note that visiting will recursively visit sub-states
vis.visit_state(this,i);
}
// The list of FSM states
// the Playing state machine contains a state which is himself a state machine
// so we have a SM containing a SM containing a SM
struct Song1_ : public msm::front::state_machine_def<Song1_,my_visitable_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;}
void accept(SomeVisitor& vis,int i) const
{
vis.visit_state(this,i);
}
struct LightOn : public msm::front::state<my_visitable_state>
{
template <class Event,class FSM>
void on_entry(Event const&,FSM& ) {std::cout << "starting: LightOn" << std::endl;}
template <class Event,class FSM>
void on_exit(Event const&,FSM& ) {std::cout << "finishing: LightOn" << std::endl;}
void accept(SomeVisitor& vis,int i) const
{
// note that visiting will recursively visit sub-states
vis.visit_state(this,i);
}
};
struct LightOff : public msm::front::state<my_visitable_state>
{
template <class Event,class FSM>
void on_entry(Event const&,FSM& ) {std::cout << "starting: LightOff" << std::endl;}
template <class Event,class FSM>
void on_exit(Event const&,FSM& ) {std::cout << "finishing: LightOff" << std::endl;}
};
// the initial state. Must be defined
typedef LightOn initial_state;
// transition actions
void turn_light_off(ThreeSec const&) { std::cout << "3s off::turn light off\n"; }
// guard conditions
typedef Song1_ s; // makes transition table cleaner
// Transition table for Song1
struct transition_table : mpl::vector1<
// Start Event Next Action Guard
// +---------+-------------+---------+---------------------+----------------------+
a_row < LightOn , ThreeSec , LightOff, &s::turn_light_off >
// +---------+-------------+---------+---------------------+----------------------+
> {};
// 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<Song1_> Song1;
struct Song2 : public msm::front::state<my_visitable_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<my_visitable_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\n"; }
void start_prev_song(PreviousSong const&) { std::cout << "Playing::start_prev_song\n"; }
// guard conditions
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 >
// +---------+-------------+---------+---------------------+----------------------+
> {};
// 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;
struct Paused : public msm::front::state<my_visitable_state>
{
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<my_visitable_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::interrupt_state<end_error,my_visitable_state>
{
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;}
void accept(SomeVisitor& vis,int i) const
{
vis.visit_state(this,i);
}
};
// 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";
}
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";}
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
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 >,
a_row < Empty , cd_detected , Stopped , &p::store_cd_info >,
// +---------+-------------+---------+---------------------+----------------------+
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 >,
// +---------+-------------+---------+---------------------+----------------------+
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;
}
};
// back-end
typedef msm::back::state_machine<player_> player;
//
// Testing utilities.
//
void pstate(player const& p)
{
static char const* const state_names[] = { "Stopped", "Open", "Empty", "Playing", "Paused","AllOk","ErrorMode","SleepMode" };
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();
// test deferred event
// deferred in Empty and Open, will be handled only after event cd_detected
p.process_event(play());
// go to Open, call on_exit on Empty, then action, then on_entry on Open
p.process_event(open_close()); pstate(p);
// visiting Paused and AllOk, but only Paused cares
SomeVisitor vis;
p.visit_current_states(boost::ref(vis),1);
p.process_event(open_close()); pstate(p);
// visiting Empty and AllOk, but only Empty cares
p.visit_current_states(boost::ref(vis),2);
p.process_event(cd_detected());
// no need to call play() as the previous event does it in its action method
//p.process_event(play());
// at this point, Play is active, along FirstSong and LightOn
pstate(p);
// visiting Playing+Song1+LightOn and AllOk, but only Playing+Song1+LightOn care
p.visit_current_states(boost::ref(vis),3);
// Stop will be active
p.process_event(stop()); pstate(p);
// visiting when both regions have an active state who wants to be visited
p.process_event(error_found());
p.visit_current_states(boost::ref(vis),5);
}
}
int main()
{
test();
return 0;
}
