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

   1 // Copyright 2010 Christophe Henry
   2 // henry UNDERSCORE christophe AT hotmail DOT com
   3 // This is an extended version of the state machine available in the boost::mpl library
   4 // Distributed under the same license as the original.
   5 // Copyright for the original version:
   6 // Copyright 2005 David Abrahams and Aleksey Gurtovoy. Distributed
   7 // under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at
   9 // http://www.boost.org/LICENSE_1_0.txt)
  10
  11 #include <vector>
  12 #include <iostream>
  13
  14 #include <boost/msm/back/state_machine.hpp>
  15 #include <boost/msm/front/euml/euml.hpp>
  16
  17 using namespace std;
  18 using namespace boost::msm::front::euml;
  19 namespace msm = boost::msm;
  20
  21 // how long the timer will ring when countdown elapsed.
  22 #define RINGING_TIME 5
  23
  24 namespace  // Concrete FSM implementation
  25 {
  26     // events
  27     BOOST_MSM_EUML_DECLARE_ATTRIBUTE(int,m_timer)
  28     BOOST_MSM_EUML_ATTRIBUTES((attributes_ << m_timer ), start_timer_attr)
  29     BOOST_MSM_EUML_EVENT_WITH_ATTRIBUTES(start_timer,start_timer_attr)
  30
  31     BOOST_MSM_EUML_EVENT(stop_timer)
  32
  33     BOOST_MSM_EUML_DECLARE_ATTRIBUTE(int,m_tick)
  34     BOOST_MSM_EUML_ATTRIBUTES((attributes_ << m_tick ), tick_attr)
  35     BOOST_MSM_EUML_EVENT_WITH_ATTRIBUTES(tick,tick_attr)
  36
  37     BOOST_MSM_EUML_EVENT(start_ringing)
  38
  39     // Concrete FSM implementation
  40
  41     // The list of FSM states
  42     BOOST_MSM_EUML_ACTION(Stopped_Entry)
  43     {
  44         template <class Event,class FSM,class STATE>
  45         void operator()(Event const&,FSM&,STATE& )
  46         {
  47             std::cout << "entering: Stopped" << std::endl;
  48         }
  49     };
  50     BOOST_MSM_EUML_STATE(( Stopped_Entry ),Stopped)
  51
  52     BOOST_MSM_EUML_ACTION(Started_Entry)
  53     {
  54         template <class Event,class FSM,class STATE>
  55         void operator()(Event const&,FSM&,STATE& )
  56         {
  57             std::cout << "entering: Started" << std::endl;
  58         }
  59     };
  60
  61     BOOST_MSM_EUML_DECLARE_ATTRIBUTE(int,m_counter)
  62     BOOST_MSM_EUML_STATE((  Started_Entry,
  63                             no_action,
  64                             attributes_ << m_counter
  65                   ),
  66                   Started)
  67
  68     BOOST_MSM_EUML_ACTION(Ringing_Entry)
  69     {
  70         template <class Event,class FSM,class STATE>
  71         void operator()(Event const&,FSM&,STATE& )
  72         {
  73             std::cout << "entering: Ringing" << std::endl;
  74         }
  75     };
  76     BOOST_MSM_EUML_DECLARE_ATTRIBUTE(int,m_ringing_cpt)
  77     BOOST_MSM_EUML_STATE((  Ringing_Entry,
  78                             no_action,
  79                             attributes_ << m_ringing_cpt
  80                   ),
  81                   Ringing)
  82
  83     // external function
  84     void do_ring(int ringing_time) {std::cout << "ringing " << ringing_time << " s" << std::endl;}
  85     // create functor and eUML function
  86     BOOST_MSM_EUML_FUNCTION(Ring_ , do_ring , ring_ , void , void )
  87
  88     // replaces the old transition table
  89     BOOST_MSM_EUML_TRANSITION_TABLE((
  90         //  +------------------------------------------------------------------------------+
  91           // When we start the countdown, the countdown value is not hardcoded but contained in the start_timer event.
  92           // We copy this value into Started
  93           Started     == Stopped + start_timer /(target_(m_counter)= event_(m_timer))         ,
  94           Stopped     == Started + stop_timer                                                 ,
  95           // internal transition
  96           Started + tick
  97                     // we here use the message queue to move to Started when the countdown is finished
  98                     // to do this we put start_ringing into the message queue
  99                     / if_then_( (source_(m_counter) -= event_(m_tick) ) <= Int_<0>(),
 100                                  process_(start_ringing) )                                        ,
 101           // when we start ringing, we give to the state its hard-coded ringing time.
 102           Ringing     == Started + start_ringing
 103                            / (target_(m_ringing_cpt) = Int_<RINGING_TIME>(),
 104                               // call the external do_ring function
 105                               ring_(Int_<RINGING_TIME>()))                                          ,
 106           // to change a bit, we now do not use the message queue but a transition conflict to solve the same problem.
 107           // When tick is fired, we have an internal transition Ringing -> Ringing, as long as Counter > 0
 108           Ringing + tick [ source_(m_ringing_cpt) - event_(m_tick) > Int_<0>() ]
 109                              /(target_(m_ringing_cpt) -= event_(m_tick) )                           ,
 110           // And we move to Stopped when the counter is 0
 111           Stopped     == Ringing + tick[source_(m_ringing_cpt)-event_(m_tick) <= Int_<0>()]   ,
 112           // we let the user manually stop the ringing by pressing any button
 113           Stopped     == Ringing + stop_timer                                                 ,
 114           Stopped     == Ringing + start_timer
 115           //  +------------------------------------------------------------------------------+
 116           ),transition_table)
 117
 118     // create a state machine "on the fly"
 119     BOOST_MSM_EUML_DECLARE_STATE_MACHINE(( transition_table, //STT
 120                                         init_ << Stopped // Init State
 121                                         ),
 122                                       SimpleTimer_) //fsm name
 123
 124     // choice of back-end
 125     typedef msm::back::state_machine<SimpleTimer_> SimpleTimer;
 126
 127     //
 128     // Testing utilities.
 129     //
 130     static char const* const state_names[] = { "Stopped", "Started","Ringing" };
 131     void pstate(SimpleTimer const& p)
 132     {
 133         std::cout << " -> " << state_names[p.current_state()[0]] << std::endl;
 134     }
 135
 136     void test()
 137     {
 138         SimpleTimer p;
 139         // needed to start the highest-level SM. This will call on_entry and mark the start of the SM
 140         p.start();
 141
 142         p.process_event(start_timer(5));pstate(p); //timer set to 5 ticks
 143         p.process_event(tick(2));pstate(p);
 144         p.process_event(tick(1));pstate(p);
 145         p.process_event(tick(1));pstate(p);
 146         p.process_event(tick(1));pstate(p);
 147         // we are now ringing, let it ring a bit
 148         p.process_event(tick(2));pstate(p);
 149         p.process_event(tick(1));pstate(p);
 150         p.process_event(tick(1));pstate(p);
 151         p.process_event(tick(1));pstate(p);
 152     }
 153 }
 154
 155 int main()
 156 {
 157     test();
 158     return 0;
 159 }