259 lines
9.3 KiB
C++
259 lines
9.3 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/phoenix/phoenix.hpp>
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// add phoenix support in eUML
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#define BOOST_MSM_EUML_PHOENIX_SUPPORT
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#include <boost/msm/back/state_machine.hpp>
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#include <boost/msm/front/euml/euml.hpp>
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using namespace std;
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using namespace boost::msm::front::euml;
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namespace msm = boost::msm;
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using namespace boost::phoenix;
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// entry/exit/action/guard logging functors
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#include "logging_functors.h"
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namespace // Concrete FSM implementation
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{
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// events
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BOOST_MSM_EUML_EVENT(end_pause)
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BOOST_MSM_EUML_EVENT(stop)
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BOOST_MSM_EUML_EVENT(pause)
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BOOST_MSM_EUML_EVENT(open_close)
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struct play_event : boost::msm::front::euml::euml_event<play_event>
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{
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};
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play_event play;
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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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// A "complicated" event type that carries some data.
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struct cd_detected_event : boost::msm::front::euml::euml_event<cd_detected_event>
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{
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cd_detected_event(){}
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cd_detected_event(std::string const& name,DiskTypeEnum disk):cd_name(name),cd_type(disk){}
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std::string cd_name;
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DiskTypeEnum cd_type;
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};
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// define an instance for a nicer transition table
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cd_detected_event cd_detected;
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// Concrete FSM implementation
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// The list of FSM states
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// state not needing any entry or exit
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BOOST_MSM_EUML_STATE((),Paused)
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// states with standard eUML actions
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BOOST_MSM_EUML_STATE(( Stopped_Entry,Stopped_Exit ),Stopped)
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BOOST_MSM_EUML_STATE(( Playing_Entry,Playing_Exit ),Playing)
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// a "standard" msm state
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struct Empty_impl : public msm::front::state<> , public euml_state<Empty_impl>
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{
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// this allows us to add some functions
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void foo() {std::cout << "Empty::foo " << std::endl;}
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// standard entry behavior
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template <class Event,class FSM>
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void on_entry(Event const& evt,FSM& fsm)
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{
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std::cout << "entering: Empty" << std::endl;
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}
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template <class Event,class FSM>
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void on_exit(Event const& evt,FSM& fsm)
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{
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std::cout << "leaving: Empty" << std::endl;
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}
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};
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//instance for use in the transition table
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Empty_impl const Empty;
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// entry and exit actions as phoenix functions
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struct open_entry_impl
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{
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typedef void result_type;
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void operator()()
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{
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cout << "entering: Open" << endl;
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}
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};
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boost::phoenix::function<open_entry_impl> open_entry;
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struct open_exit_impl
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{
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typedef void result_type;
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void operator()()
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{
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cout << "leaving: Open" << endl;
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}
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};
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boost::phoenix::function<open_exit_impl> open_exit;
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// a state using phoenix for entry/exit actions
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BOOST_MSM_EUML_STATE(( open_entry(),open_exit() ),Open)
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// actions and guards using boost::phoenix
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struct start_playback_impl
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{
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typedef void result_type;
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void operator()()
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{
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cout << "calling: start_playback" << endl;
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}
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};
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boost::phoenix::function<start_playback_impl> start_playback;
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// a guard taking the event as argument
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struct good_disk_format_impl
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{
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typedef bool result_type;
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template <class Event>
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bool operator()(Event 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.cd_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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std::cout << "good disk" << std::endl;
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return true;
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}
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};
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boost::phoenix::function<good_disk_format_impl> good_disk_format;
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// a simple action
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struct store_cd_info_impl
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{
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typedef void result_type;
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void operator()()
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{
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cout << "calling: store_cd_info" << endl;
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}
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};
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boost::phoenix::function<store_cd_info_impl> store_cd_info;
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// an action taking the fsm as argument and sending it a new event
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struct process_play_impl
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{
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typedef void result_type;
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template <class Fsm>
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void operator()(Fsm& fsm)
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{
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cout << "queuing a play event" << endl;
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fsm.process_event(play);
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}
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};
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// it is also possible to use BOOST_PHOENIX_ADAPT_CALLABLE to avoid defining a global variable
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BOOST_PHOENIX_ADAPT_CALLABLE(process_play, process_play_impl, 1)
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// transition table. Actions and guards are written as phoenix functions
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BOOST_MSM_EUML_TRANSITION_TABLE((
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//an action without arguments
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Playing == Stopped + play / start_playback() ,
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Playing == Paused + end_pause ,
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// +------------------------------------------------------------------------------+
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Empty == Open + open_close ,
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// +------------------------------------------------------------------------------+
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Open == Empty + open_close ,
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Open == Paused + open_close ,
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Open == Stopped + open_close ,
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Open == Playing + open_close ,
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// +------------------------------------------------------------------------------+
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Paused == Playing + pause ,
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// +------------------------------------------------------------------------------+
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Stopped == Playing + stop ,
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Stopped == Paused + stop ,
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// a guard taking the event as argument
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// and an action made of a phoenix expression of 2 actions
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// _event is a placeholder for the current event
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// _fsm is a placeholder for the current state machine
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Stopped == Empty + cd_detected [good_disk_format(_event)]
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/ (store_cd_info(),process_play(_fsm)),
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Stopped == Stopped + stop
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// +------------------------------------------------------------------------------+
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),transition_table)
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// create a state machine "on the fly"
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BOOST_MSM_EUML_DECLARE_STATE_MACHINE(( transition_table, //STT
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init_ << Empty, // Init State
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no_action, // Entry
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no_action, // Exit
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attributes_ << no_attributes_, // Attributes
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configure_ << no_configure_, // configuration
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Log_No_Transition // no_transition handler
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),
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player_) //fsm name
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// or simply, if no no_transition handler needed:
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//BOOST_MSM_EUML_DECLARE_STATE_MACHINE(( transition_table, //STT
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// Empty // Init State
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// ),player_)
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// choice of 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", "Paused", "Open", "Empty", "Playing" };
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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_event("louie, louie",DISK_DVD)); pstate(p);
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p.process_event(
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cd_detected_event("louie, louie",DISK_CD)); pstate(p);
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// no need to call play as the previous event does it in its action method
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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 none is defined in the transition table
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p.process_event(stop); pstate(p);
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// test call to no_transition
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p.process_event(pause); 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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