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