265 lines
11 KiB
C++
265 lines
11 KiB
C++
// Copyright 2010 Gordon Woodhull
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// modified from MSMv2.10/libs/msm/doc/HTML/examples/SimpleTutorial.cpp
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// for the purpose of showing how to run mpl_graph algorithms on MSMs
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// and distributed same license as source
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// Copyright 2008 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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// 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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// mpl_graph graph implementation and depth first search
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#include <boost/msm/mpl_graph/incidence_list_graph.hpp>
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#include <boost/msm/mpl_graph/depth_first_search.hpp>
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#include <boost/msm/mpl_graph/breadth_first_search.hpp>
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namespace msm = boost::msm;
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namespace mpl = boost::mpl;
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namespace mpl_graph = boost::msm::mpl_graph;
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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 open_close {};
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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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// 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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};
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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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// sm_ptr still supported but deprecated as functors are a much better way to do the same thing
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struct Stopped : public msm::front::state<msm::front::default_base_state,msm::front::sm_ptr>
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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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void set_sm_ptr(player_* pl)
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{
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m_player=pl;
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}
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player_* m_player;
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};
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struct Playing : 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: 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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};
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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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// 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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// used to show a transition conflict. This guard will simply deactivate one transition and thus
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// solve the conflict
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bool auto_start(cd_detected const&)
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{
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return false;
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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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_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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row < Empty , cd_detected , Stopped , &p::store_cd_info ,&p::good_disk_format >,
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row < Empty , cd_detected , Playing , &p::store_cd_info ,&p::auto_start >,
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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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// transition table is already an incidence list;
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// select Edge, Source, Target = pair<Start,Event>, Start, Next
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// making Start part of Edge is necessary because Edge tags have to be unique
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template<typename Row>
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struct row_to_incidence :
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mpl::vector<mpl::pair<typename Row::Target, typename Row::Evt>, typename Row::Source, typename Row::Target> {};
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typedef mpl::fold<player_::transition_table,
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mpl::vector<>,
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mpl::push_back<mpl::_1, row_to_incidence<mpl::_2> > >::type
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transition_incidence_list;
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typedef mpl_graph::incidence_list_graph<transition_incidence_list>
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transition_graph;
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struct preordering_dfs_visitor : mpl_graph::dfs_default_visitor_operations {
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template<typename Node, typename Graph, typename State>
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struct discover_vertex :
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mpl::push_back<State, Node>
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{};
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};
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typedef mpl::first<mpl_graph::
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depth_first_search<transition_graph,
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preordering_dfs_visitor,
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mpl::vector<>,
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player_::initial_state>::type>::type
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dfs_from_initial_state;
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BOOST_MPL_ASSERT(( mpl::equal<dfs_from_initial_state,
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mpl::vector<Empty,Open,Stopped,Playing,Paused> > ));
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struct preordering_bfs_visitor : mpl_graph::bfs_default_visitor_operations {
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template<typename Node, typename Graph, typename State>
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struct discover_vertex :
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mpl::push_back<State, Node>
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{};
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};
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typedef mpl::first<mpl_graph::
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breadth_first_search<transition_graph,
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preordering_bfs_visitor,
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mpl::vector<>,
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player_::initial_state>::type>::type
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bfs_from_initial_state;
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// yawn, BFS happens to produce the same result as DFS for this example
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BOOST_MPL_ASSERT(( mpl::equal<bfs_from_initial_state,
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mpl::vector<Empty,Open,Stopped,Playing,Paused> > ));
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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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// 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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// 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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