ceph/src/boost/libs/msm/doc/HTML/examples/EumlInternal.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 using namespace boost::msm::front;
  20 namespace msm = boost::msm;
  21
  22 // entry/exit/action/guard logging functors
  23 #include "logging_functors.h"
  24
  25 namespace  // Concrete FSM implementation
  26 {
  27     // events
  28     BOOST_MSM_EUML_EVENT(play)
  29     BOOST_MSM_EUML_EVENT(end_pause)
  30     BOOST_MSM_EUML_EVENT(stop)
  31     BOOST_MSM_EUML_EVENT(pause)
  32     BOOST_MSM_EUML_EVENT(open_close)
  33     BOOST_MSM_EUML_EVENT(internal_event)
  34
  35     // A "complicated" event type that carries some data.
  36     BOOST_MSM_EUML_DECLARE_ATTRIBUTE(std::string,cd_name)
  37     BOOST_MSM_EUML_DECLARE_ATTRIBUTE(DiskTypeEnum,cd_type)
  38     BOOST_MSM_EUML_ATTRIBUTES((attributes_ << cd_name << cd_type ), cd_detected_attributes)
  39     BOOST_MSM_EUML_EVENT_WITH_ATTRIBUTES(cd_detected,cd_detected_attributes)
  40
  41     // Concrete FSM implementation
  42
  43     // The list of FSM states
  44     BOOST_MSM_EUML_STATE(( Empty_Entry,Empty_Exit ),Empty)
  45     BOOST_MSM_EUML_STATE(( Open_Entry,Open_Exit ),Open)
  46     BOOST_MSM_EUML_STATE(( Stopped_Entry,Stopped_Exit ),Stopped)
  47     BOOST_MSM_EUML_STATE(( Playing_Entry,Playing_Exit ),Playing)
  48     // state not needing any entry or exit
  49     BOOST_MSM_EUML_STATE((),Paused)
  50
  51     // guard conditions
  52     BOOST_MSM_EUML_ACTION(good_disk_format)
  53     {
  54         template <class FSM,class EVT,class SourceState,class TargetState>
  55         bool operator()(EVT const& evt,FSM&,SourceState& ,TargetState& )
  56         {
  57             // to test a guard condition, let's say we understand only CDs, not DVD
  58             if (evt.get_attribute(cd_type)!=DISK_CD)
  59             {
  60                 std::cout << "wrong disk, sorry" << std::endl;
  61                 // just for logging, does not block any transition
  62                 return true;
  63             }
  64             std::cout << "good disk" << std::endl;
  65             return true;
  66         }
  67     };
  68     // replaces the old transition table
  69     BOOST_MSM_EUML_TRANSITION_TABLE((
  70           Playing   == Stopped  + play        / start_playback ,
  71           Playing   == Paused   + end_pause   / resume_playback,
  72           //  +------------------------------------------------------------------------------+
  73           Empty     == Open     + open_close  / close_drawer,
  74           //  +------------------------------------------------------------------------------+
  75           Open      == Empty    + open_close  / open_drawer,
  76           Open      == Paused   + open_close  / stop_and_open,
  77           Open      == Stopped  + open_close  / open_drawer,
  78           Open      == Playing  + open_close  / stop_and_open,
  79           Open                  + open_close  [internal_guard1] / internal_action1,
  80           Open                  + open_close  [internal_guard2] / internal_action2,
  81           Open                  + internal_event / internal_action                  ,
  82           //  +------------------------------------------------------------------------------+
  83           Paused    == Playing  + pause       / pause_playback,
  84           //  +------------------------------------------------------------------------------+
  85           Stopped   == Playing  + stop        / stop_playback,
  86           Stopped   == Paused   + stop        / stop_playback,
  87           Stopped   == Empty    + cd_detected [good_disk_format&&
  88                                                      (event_(cd_type)==Int_<DISK_CD>())]
  89                                                     / (store_cd_info,process_(play)),
  90           Stopped   == Stopped  + stop
  91           //  +------------------------------------------------------------------------------+
  92           ),transition_table)
  93
  94
  95     // create a state machine "on the fly"
  96     BOOST_MSM_EUML_DECLARE_STATE_MACHINE(( transition_table, //STT
  97                                         init_ << Empty, // Init State
  98                                         no_action, // Entry
  99                                         no_action, // Exit
 100                                         attributes_ << no_attributes_, // Attributes
 101                                         configure_ << no_configure_, // configuration
 102                                         Log_No_Transition // no_transition handler
 103                                         ),
 104                                       player_) //fsm name
 105     // choice of back-end
 106     typedef msm::back::state_machine<player_> player;
 107
 108     //
 109     // Testing utilities.
 110     //
 111     static char const* const state_names[] = { "Stopped", "Paused", "Open", "Empty", "Playing" };
 112     void pstate(player const& p)
 113     {
 114         std::cout << " -> " << state_names[p.current_state()[0]] << std::endl;
 115     }
 116
 117     void test()
 118     {
 119         player p;
 120         // needed to start the highest-level SM. This will call on_entry and mark the start of the SM
 121         p.start();
 122         // go to Open, call on_exit on Empty, then action, then on_entry on Open
 123         p.process_event(open_close); pstate(p);
 124         std::cout << "sending internal event (not rejected)" << std::endl;
 125         p.process_event(internal_event);
 126         std::cout << "sending open_close event. Conflict with internal transitions (rejecting event)" << std::endl;
 127         p.process_event(open_close); pstate(p);
 128         // will be rejected, wrong disk type
 129         p.process_event(
 130             cd_detected("louie, louie",DISK_DVD)); pstate(p);
 131         p.process_event(
 132             cd_detected("louie, louie",DISK_CD)); pstate(p);
 133         // no need to call play() as the previous event does it in its action method
 134         //p.process_event(play);
 135
 136         // at this point, Play is active
 137         p.process_event(pause); pstate(p);
 138         // go back to Playing
 139         p.process_event(end_pause);  pstate(p);
 140         p.process_event(pause); pstate(p);
 141         p.process_event(stop);  pstate(p);
 142         // event leading to the same state
 143         // no action method called as none is defined in the transition table
 144         p.process_event(stop);  pstate(p);
 145         // test call to no_transition
 146         p.process_event(pause); pstate(p);
 147     }
 148 }
 149
 150 int main()
 151 {
 152     test();
 153     return 0;
 154 }