ceph/src/boost/libs/msm/doc/PDF/examples/SimpleTutorialWithEumlTable.cpp

   1 #include <iostream>
   2 // back-end
   3 #include <boost/msm/back/state_machine.hpp>
   4 //front-end
   5 #include <boost/msm/front/state_machine_def.hpp>
   6 #include <boost/msm/front/euml/euml.hpp>
   7
   8 namespace msm = boost::msm;
   9 namespace mpl = boost::mpl;
  10 using namespace std;
  11
  12 // entry/exit/action/guard logging functors
  13 #include "logging_functors.h"
  14
  15 namespace
  16 {
  17     // events
  18     struct play_impl : msm::front::euml::euml_event<play_impl> {};
  19     struct end_pause_impl : msm::front::euml::euml_event<end_pause_impl>{};
  20     struct stop_impl : msm::front::euml::euml_event<stop_impl>{};
  21     struct pause_impl : msm::front::euml::euml_event<pause_impl>{};
  22     struct open_close_impl : msm::front::euml::euml_event<open_close_impl>{};
  23     struct cd_detected_impl : msm::front::euml::euml_event<cd_detected_impl>{};
  24
  25     // define some dummy instances for use in the transition table
  26     // it is also possible to default-construct them instead:
  27     // struct play {};
  28     // inside the table: play()
  29     play_impl play;
  30     end_pause_impl end_pause;
  31     stop_impl stop;
  32     pause_impl pause;
  33     open_close_impl open_close;
  34     cd_detected_impl cd_detected;
  35
  36     // The list of FSM states
  37     // they have to be declared outside of the front-end only to make VC happy :(
  38     // note: gcc would have no problem
  39     struct Empty_impl : public msm::front::state<> , public msm::front::euml::euml_state<Empty_impl>
  40     {
  41         // every (optional) entry/exit methods get the event passed.
  42         template <class Event,class FSM>
  43         void on_entry(Event const&,FSM& ) {std::cout << "entering: Empty" << std::endl;}
  44         template <class Event,class FSM>
  45         void on_exit(Event const&,FSM& ) {std::cout << "leaving: Empty" << std::endl;}
  46     };
  47     struct Open_impl : public msm::front::state<> , public msm::front::euml::euml_state<Open_impl>
  48     {
  49         template <class Event,class FSM>
  50         void on_entry(Event const& ,FSM&) {std::cout << "entering: Open" << std::endl;}
  51         template <class Event,class FSM>
  52         void on_exit(Event const&,FSM& ) {std::cout << "leaving: Open" << std::endl;}
  53     };
  54
  55     struct Stopped_impl : public msm::front::state<> , public msm::front::euml::euml_state<Stopped_impl>
  56     {
  57         template <class Event,class FSM>
  58         void on_entry(Event const& ,FSM&) {std::cout << "entering: Stopped" << std::endl;}
  59         template <class Event,class FSM>
  60         void on_exit(Event const&,FSM& ) {std::cout << "leaving: Stopped" << std::endl;}
  61     };
  62
  63     struct Playing_impl : public msm::front::state<> , public msm::front::euml::euml_state<Playing_impl>
  64     {
  65         template <class Event,class FSM>
  66         void on_entry(Event const&,FSM& ) {std::cout << "entering: Playing" << std::endl;}
  67         template <class Event,class FSM>
  68         void on_exit(Event const&,FSM& ) {std::cout << "leaving: Playing" << std::endl;}
  69     };
  70
  71     // state not defining any entry or exit
  72     struct Paused_impl : public msm::front::state<> , public msm::front::euml::euml_state<Paused_impl>
  73     {
  74     };
  75     //to make the transition table more readable
  76     Empty_impl const Empty;
  77     Open_impl const Open;
  78     Stopped_impl const Stopped;
  79     Playing_impl const Playing;
  80     Paused_impl const Paused;
  81
  82     // front-end: define the FSM structure
  83     struct player_ : public msm::front::state_machine_def<player_>
  84     {
  85
  86         // the initial state of the player SM. Must be defined
  87         typedef Empty_impl initial_state;
  88
  89         // Transition table for player
  90         // replaces the old transition table
  91         BOOST_MSM_EUML_DECLARE_TRANSITION_TABLE((
  92           Stopped + play        / start_playback                    == Playing               ,
  93           Stopped + open_close  / open_drawer                       == Open                  ,
  94           Stopped + stop                                            == Stopped               ,
  95           //  +------------------------------------------------------------------------------+
  96           Open    + open_close  / close_drawer                      == Empty                 ,
  97           //  +------------------------------------------------------------------------------+
  98           Empty   + open_close  / open_drawer                       == Open                  ,
  99           Empty   + cd_detected /(store_cd_info,
 100                                   msm::front::euml::process_(play)) == Stopped               ,
 101           //  +------------------------------------------------------------------------------+
 102           Playing + stop        / stop_playback                     == Stopped               ,
 103           Playing + pause       / pause_playback                    == Paused                ,
 104           Playing + open_close  / stop_and_open                     == Open                  ,
 105           //  +------------------------------------------------------------------------------+
 106           Paused  + end_pause   / resume_playback                   == Playing               ,
 107           Paused  + stop        / stop_playback                     == Stopped               ,
 108           Paused  + open_close  / stop_and_open                     == Open
 109           //  +------------------------------------------------------------------------------+
 110           ),transition_table)
 111
 112         // Replaces the default no-transition response.
 113         template <class FSM,class Event>
 114         void no_transition(Event const& e, FSM&,int state)
 115         {
 116             std::cout << "no transition from state " << state
 117                 << " on event " << typeid(e).name() << std::endl;
 118         }
 119     };
 120     // Pick a back-end
 121     typedef msm::back::state_machine<player_> player;
 122
 123     //
 124     // Testing utilities.
 125     //
 126     static char const* const state_names[] = { "Stopped", "Open", "Empty", "Playing", "Paused" };
 127     void pstate(player const& p)
 128     {
 129         std::cout << " -> " << state_names[p.current_state()[0]] << std::endl;
 130     }
 131
 132     void test()
 133     {
 134                 player p;
 135         // needed to start the highest-level SM. This will call on_entry and mark the start of the SM
 136         p.start();
 137         // go to Open, call on_exit on Empty, then action, then on_entry on Open
 138         p.process_event(open_close); pstate(p);
 139         p.process_event(open_close); pstate(p);
 140         p.process_event(cd_detected); pstate(p);
 141
 142         // at this point, Play is active
 143         p.process_event(pause); pstate(p);
 144         // go back to Playing
 145         p.process_event(end_pause);  pstate(p);
 146         p.process_event(pause); pstate(p);
 147         p.process_event(stop);  pstate(p);
 148         // event leading to the same state
 149         // no action method called as it is not present in the transition table
 150         p.process_event(stop);  pstate(p);
 151     }
 152 }
 153
 154 int main()
 155 {
 156     test();
 157     return 0;
 158 }