ceph/src/boost/libs/msm/doc/HTML/examples/DirectEntryTutorial.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 // back-end
  14 #include <boost/msm/back/state_machine.hpp>
  15 //front-end
  16 #include <boost/msm/front/state_machine_def.hpp>
  17
  18 namespace msm = boost::msm;
  19 namespace mpl = boost::mpl;
  20
  21 namespace
  22 {
  23     // events
  24     struct event1 {};
  25     struct event2 {};
  26     struct event3 {};
  27     struct event4 {};
  28     struct event5 {};
  29     struct event6
  30     {
  31         event6(){}
  32         template <class Event>
  33         event6(Event const&){}
  34     };
  35     // front-end: define the FSM structure
  36     struct Fsm_ : public msm::front::state_machine_def<Fsm_>
  37     {
  38         // The list of FSM states
  39         struct State1 : public msm::front::state<>
  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: State1" << std::endl;}
  44             template <class Event,class FSM>
  45             void on_exit(Event const&,FSM& ) {std::cout << "leaving: State1" << std::endl;}
  46         };
  47         struct State2 : public msm::front::state<>
  48         {
  49             // every (optional) entry/exit methods get the event passed.
  50             template <class Event,class FSM>
  51             void on_entry(Event const&,FSM& ) {std::cout << "entering: State2" << std::endl;}
  52             template <class Event,class FSM>
  53             void on_exit(Event const&,FSM& ) {std::cout << "leaving: State2" << std::endl;}
  54         };
  55         struct SubFsm2_ : public msm::front::state_machine_def<SubFsm2_>
  56         {
  57             typedef msm::back::state_machine<SubFsm2_> SubFsm2;
  58
  59             template <class Event,class FSM>
  60             void on_entry(Event const&,FSM& ) {std::cout << "entering: SubFsm2" << std::endl;}
  61             template <class Event,class FSM>
  62             void on_exit(Event const&,FSM& ) {std::cout << "leaving: SubFsm2" << std::endl;}
  63
  64             struct SubState1 : public msm::front::state<>
  65             {
  66                 template <class Event,class FSM>
  67                 void on_entry(Event const&,FSM& ) {std::cout << "entering: SubFsm2::SubState1" << std::endl;}
  68                 template <class Event,class FSM>
  69                 void on_exit(Event const&,FSM& ) {std::cout << "leaving: SubFsm2::SubState1" << std::endl;}
  70             };
  71             struct SubState1b : public msm::front::state<>
  72             {
  73                 template <class Event,class FSM>
  74                 void on_entry(Event const&,FSM& ) {std::cout << "entering: SubFsm2::SubState1b" << std::endl;}
  75                 template <class Event,class FSM>
  76                 void on_exit(Event const&,FSM& ) {std::cout << "leaving: SubFsm2::SubState1b" << std::endl;}
  77             };
  78             struct SubState2 : public msm::front::state<> , public msm::front::explicit_entry<0>
  79             {
  80                 template <class Event,class FSM>
  81                 void on_entry(Event const&,FSM& ) {std::cout << "entering: SubFsm2::SubState2" << std::endl;}
  82                 template <class Event,class FSM>
  83                 void on_exit(Event const&,FSM& ) {std::cout << "leaving: SubFsm2::SubState2" << std::endl;}
  84             };
  85             struct SubState2b : public msm::front::state<> , public msm::front::explicit_entry<1>
  86             {
  87                 template <class Event,class FSM>
  88                 void on_entry(Event const&,FSM& ) {std::cout << "entering: SubFsm2::SubState2b" << std::endl;}
  89                 template <class Event,class FSM>
  90                 void on_exit(Event const&,FSM& ) {std::cout << "leaving: SubFsm2::SubState2b" << std::endl;}
  91             };
  92             // test with a pseudo entry
  93             struct PseudoEntry1 : public msm::front::entry_pseudo_state<0>
  94             {
  95                 template <class Event,class FSM>
  96                 void on_entry(Event const&,FSM& ) {std::cout << "entering: SubFsm2::PseudoEntry1" << std::endl;}
  97                 template <class Event,class FSM>
  98                 void on_exit(Event const&,FSM& ) {std::cout << "leaving: SubFsm2::PseudoEntry1" << std::endl;}
  99             };
 100             struct SubState3 : public msm::front::state<>
 101             {
 102                 template <class Event,class FSM>
 103                 void on_entry(Event const&,FSM& ) {std::cout << "entering: SubFsm2::SubState3" << std::endl;}
 104                 template <class Event,class FSM>
 105                 void on_exit(Event const&,FSM& ) {std::cout << "leaving: SubFsm2::SubState3" << std::endl;}
 106             };
 107             struct SubState3b : public msm::front::state<>
 108             {
 109                 template <class Event,class FSM>
 110                 void on_entry(Event const&,FSM& ) {std::cout << "entering: SubFsm2::SubState3b" << std::endl;}
 111                 template <class Event,class FSM>
 112                 void on_exit(Event const&,FSM& ) {std::cout << "leaving: SubFsm2::SubState3b" << std::endl;}
 113             };
 114             struct PseudoExit1 : public msm::front::exit_pseudo_state<event6>
 115             {
 116                 template <class Event,class FSM>
 117                 void on_entry(Event const&,FSM& ) {std::cout << "entering: SubFsm2::PseudoExit1" << std::endl;}
 118                 template <class Event,class FSM>
 119                 void on_exit(Event const&,FSM& ) {std::cout << "leaving: SubFsm2::PseudoExit1" << std::endl;}
 120             };
 121             // action methods
 122             void entry_action(event4 const&)
 123             {
 124                 std::cout << "calling entry_action" << std::endl;
 125             }
 126             // the initial state. Must be defined
 127             typedef mpl::vector<SubState1,SubState1b> initial_state;
 128
 129             typedef mpl::vector<SubState2b> explicit_creation;
 130
 131             // Transition table for SubFsm2
 132             struct transition_table : mpl::vector<
 133                 //      Start          Event         Next         Action                  Guard
 134                 //    +--------------+-------------+------------+------------------------+----------------------+
 135                 a_row < PseudoEntry1 , event4      , SubState3  ,&SubFsm2_::entry_action                        >,
 136                 _row  < SubState2    , event6      , SubState1                                                  >,
 137                 _row  < SubState3    , event5      , PseudoExit1                                                >
 138                 //    +--------------+-------------+------------+------------------------+----------------------+
 139             > {};
 140             // Replaces the default no-transition response.
 141             template <class FSM,class Event>
 142             void no_transition(Event const& e, FSM&,int state)
 143             {
 144                 std::cout << "no transition from state " << state
 145                     << " on event " << typeid(e).name() << std::endl;
 146             }
 147         };
 148         typedef msm::back::state_machine<SubFsm2_> SubFsm2;
 149
 150         // the initial state of the player SM. Must be defined
 151         typedef State1 initial_state;
 152
 153         // transition actions
 154         // guard conditions
 155
 156         // Transition table for Fsm
 157         struct transition_table : mpl::vector<
 158             //    Start                 Event    Next                                 Action  Guard
 159             //   +---------------------+--------+------------------------------------+-------+--------+
 160             _row < State1              , event1 , SubFsm2                                             >,
 161             _row < State1              , event2 , SubFsm2::direct<SubFsm2_::SubState2>                >,
 162             _row < State1              , event3 , mpl::vector<SubFsm2::direct<SubFsm2_::SubState2>,
 163                                                               SubFsm2::direct<SubFsm2_::SubState2b> > >,
 164             _row < State1              , event4 , SubFsm2::entry_pt
 165                                                         <SubFsm2_::PseudoEntry1>                      >,
 166             //   +---------------------+--------+------------------------------------+-------+--------+
 167             _row < SubFsm2             , event1 , State1                                              >,
 168             _row < SubFsm2::exit_pt
 169                 <SubFsm2_::PseudoExit1>, event6 , State2                                              >
 170             //   +---------------------+--------+------------------------------------+-------+--------+
 171         > {};
 172
 173         // Replaces the default no-transition response.
 174         template <class FSM,class Event>
 175         void no_transition(Event const& e, FSM&,int state)
 176         {
 177             std::cout << "no transition from state " << state
 178                 << " on event " << typeid(e).name() << std::endl;
 179         }
 180     };
 181     typedef msm::back::state_machine<Fsm_> Fsm;
 182
 183     //
 184     // Testing utilities.
 185     //
 186     static char const* const state_names[] = { "State1", "SubFsm2","State2" };
 187     void pstate(Fsm const& p)
 188     {
 189         std::cout << " -> " << state_names[p.current_state()[0]] << std::endl;
 190     }
 191
 192     void test()
 193     {
 194         Fsm p;
 195         // needed to start the highest-level SM. This will call on_entry and mark the start of the SM
 196         p.start();
 197         std::cout << "Simply move in and out of the composite, activate init states" << std::endl;
 198         p.process_event(event1()); pstate(p);
 199         p.process_event(event1()); pstate(p);
 200         std::cout << "Direct entry into SubFsm2::SubState2, then transition to SubState1 and back to State1" << std::endl;
 201         p.process_event(event2()); pstate(p);
 202         p.process_event(event6()); pstate(p);
 203         p.process_event(event1()); pstate(p);
 204         std::cout << "processing fork to SubFsm2::SubState2 and SubFsm2::SubState2b" << std::endl;
 205         p.process_event(event3()); pstate(p);
 206         p.process_event(event1()); pstate(p);
 207         std::cout << "processing entry pseudo state" << std::endl;
 208         p.process_event(event4()); pstate(p);
 209         p.process_event(event1()); pstate(p);
 210         std::cout << "processing entry + exit pseudo state" << std::endl;
 211         p.process_event(event4()); pstate(p);
 212         std::cout << "using exit pseudo state" << std::endl;
 213         p.process_event(event5()); pstate(p);
 214     }
 215 }
 216
 217 int main()
 218 {
 219     test();
 220     return 0;
 221 }