ceph/src/boost/libs/msm/doc/HTML/examples/ActivateStateBeforeTransitionEuml.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 <iostream>
  12
  13 #include <boost/msm/back/state_machine.hpp>
  14 #include <boost/msm/front/state_machine_def.hpp>
  15 #include <boost/msm/front/euml/euml.hpp>
  16
  17 using namespace std;
  18 namespace msm = boost::msm;
  19 namespace mpl = boost::mpl;
  20 using namespace boost::msm::front::euml;
  21
  22
  23 namespace // Concrete FSM implementation
  24 {
  25     // events
  26     BOOST_MSM_EUML_EVENT(connect)
  27     BOOST_MSM_EUML_EVENT(disconnect)
  28
  29     // flag
  30     BOOST_MSM_EUML_FLAG(is_connected)
  31
  32     BOOST_MSM_EUML_ACTION(SignalConnect)
  33     {
  34         template <class FSM,class EVT,class SourceState,class TargetState>
  35         void operator()(EVT const& ,FSM& fsm,SourceState& ,TargetState& )
  36         {
  37             // by default, this would be wrong (shows false)
  38             cout << "SignalConnect. Connected? "
  39                  << std::boolalpha
  40                  << fsm.template is_flag_active<BOOST_MSM_EUML_FLAG_NAME(is_connected)>() << endl;
  41         }
  42     };
  43     BOOST_MSM_EUML_ACTION(SignalDisconnect)
  44     {
  45         template <class FSM,class EVT,class SourceState,class TargetState>
  46         void operator()(EVT const& ,FSM& fsm,SourceState& ,TargetState& )
  47         {
  48             // by default, this would be wrong (shows true)
  49             cout << "SignalDisconnect. Connected? "
  50                  << std::boolalpha
  51                  << fsm.template is_flag_active<BOOST_MSM_EUML_FLAG_NAME(is_connected)>()
  52                  << endl;
  53         }
  54     };
  55
  56     // The list of FSM states
  57     BOOST_MSM_EUML_ACTION(Connected_Entry)
  58     {
  59         template <class Event,class FSM,class STATE>
  60         void operator()(Event const&,FSM&,STATE& )
  61         {
  62             std::cout << "entering: Connected" << std::endl;
  63         }
  64     };
  65     BOOST_MSM_EUML_ACTION(Connected_Exit)
  66     {
  67         template <class Event,class FSM,class STATE>
  68         void operator()(Event const&,FSM&,STATE& )
  69         {
  70             std::cout << "leaving: Connected" << std::endl;
  71         }
  72     };
  73     BOOST_MSM_EUML_STATE(( Connected_Entry,Connected_Exit,
  74                            attributes_ << no_attributes_,
  75                            configure_<< is_connected ),Connected)
  76
  77     BOOST_MSM_EUML_ACTION(Disconnected_Entry)
  78     {
  79         template <class Event,class FSM,class STATE>
  80         void operator()(Event const&,FSM&,STATE& )
  81         {
  82             std::cout << "entering: Disconnected" << std::endl;
  83         }
  84     };
  85     BOOST_MSM_EUML_ACTION(Disconnected_Exit)
  86     {
  87         template <class Event,class FSM,class STATE>
  88         void operator()(Event const&,FSM&,STATE& )
  89         {
  90             std::cout << "leaving: Disconnected" << std::endl;
  91         }
  92     };
  93     BOOST_MSM_EUML_STATE(( Disconnected_Entry,Disconnected_Exit ),Disconnected)
  94
  95     // replaces the old transition table
  96     BOOST_MSM_EUML_TRANSITION_TABLE((
  97           Disconnected  == Connected    + disconnect    / SignalDisconnect  ,
  98           Connected     == Disconnected + connect       / SignalConnect
  99           //  +------------------------------------------------------------------------------+
 100           ),transition_table)
 101
 102     BOOST_MSM_EUML_ACTION(Log_No_Transition)
 103     {
 104         template <class FSM,class Event>
 105         void operator()(Event const& e,FSM&,int state)
 106         {
 107             std::cout << "no transition from state " << state
 108                 << " on event " << typeid(e).name() << std::endl;
 109         }
 110     };
 111
 112     // create a state machine "on the fly"
 113     BOOST_MSM_EUML_DECLARE_STATE_MACHINE(( transition_table, //STT
 114                                         init_ << Disconnected, // Init State
 115                                         no_action, // Entry
 116                                         no_action, // Exit
 117                                         attributes_ << no_attributes_, // Attributes
 118                                         configure_ << switch_active_before_transition, // configuration
 119                                         Log_No_Transition // no_transition handler
 120                                         ),
 121                                       Connection_) //fsm name
 122
 123     typedef msm::back::state_machine<Connection_> Connection;
 124
 125     void test()
 126     {
 127         Connection connection;
 128         // needed to start the highest-level SM. This will call on_entry and mark the start of the SM
 129         connection.start();
 130         // signal a connection
 131         connection.process_event(connect);
 132         // signal a disconnection
 133         connection.process_event(disconnect);
 134         connection.stop();
 135     }
 136 }
 137
 138 int main()
 139 {
 140     test();
 141     return 0;
 142 }
 143
 144