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/euml/euml.hpp>
15
16 using namespace std;
17 using namespace boost::msm::front::euml;
18 namespace msm = boost::msm;
19 namespace mpl = boost::mpl;
20
21 // entry/exit/action/guard logging functors
22 #include "logging_functors.h"
23
24 namespace // Concrete FSM implementation
25 {
26 // events
27 BOOST_MSM_EUML_EVENT(play)
28 BOOST_MSM_EUML_EVENT(end_pause)
29 BOOST_MSM_EUML_EVENT(stop)
30 BOOST_MSM_EUML_EVENT(pause)
31 BOOST_MSM_EUML_EVENT(open_close)
32 BOOST_MSM_EUML_EVENT(next_song)
33 BOOST_MSM_EUML_EVENT(previous_song)
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 // The list of FSM states
43 // state not defining any entry or exit
44 BOOST_MSM_EUML_STATE((),Paused)
45 BOOST_MSM_EUML_STATE(( Empty_Entry,Empty_Exit ),Empty)
46 BOOST_MSM_EUML_STATE(( Open_Entry,Open_Exit ),Open)
47 BOOST_MSM_EUML_STATE(( Stopped_Entry,Stopped_Exit ),Stopped)
48
49
50 // Playing is now a state machine itself.
51
52 // It has 3 substates
53 BOOST_MSM_EUML_STATE(( Song1_Entry,Song1_Exit ),Song1)
54 BOOST_MSM_EUML_STATE(( Song2_Entry,Song2_Exit ),Song2)
55 BOOST_MSM_EUML_STATE(( Song3_Entry,Song3_Exit ),Song3)
56
57
58 // Playing has a transition table
59 BOOST_MSM_EUML_TRANSITION_TABLE((
60 // +------------------------------------------------------------------------------+
61 Song2 == Song1 + next_song / start_next_song,
62 Song1 == Song2 + previous_song / start_prev_song,
63 Song3 == Song2 + next_song / start_next_song,
64 Song2 == Song3 + previous_song / start_prev_song
65 // +------------------------------------------------------------------------------+
66 ),playing_transition_table )
67
68 // VC9 cannot compile the typedef with build_sm if one is also used for player
69 BOOST_MSM_EUML_DECLARE_STATE_MACHINE( (playing_transition_table, //STT
70 init_ << Song1 // Init State
71 ),Playing_)
72 // choice of back-end
73 typedef msm::back::state_machine<Playing_,
74 msm::back::ShallowHistory<mpl::vector<BOOST_MSM_EUML_EVENT_NAME(end_pause)> > > Playing_type;
75 Playing_type const Playing;
76
77 // guard conditions
BOOST_MSM_EUML_ACTION(good_disk_format)78 BOOST_MSM_EUML_ACTION(good_disk_format)
79 {
80 template <class FSM,class EVT,class SourceState,class TargetState>
81 bool operator()(EVT const& evt,FSM&,SourceState& ,TargetState& )
82 {
83 // to test a guard condition, let's say we understand only CDs, not DVD
84 if (evt.get_attribute(cd_type)!=DISK_CD)
85 {
86 std::cout << "wrong disk, sorry" << std::endl;
87 // just for logging, does not block any transition
88 return true;
89 }
90 std::cout << "good disk" << std::endl;
91 return true;
92 }
93 };
94 // replaces the old transition table
95 BOOST_MSM_EUML_TRANSITION_TABLE((
96 Playing == Stopped + play / start_playback,
97 Playing == Paused + end_pause / resume_playback,
98 // +------------------------------------------------------------------------------+
99 Empty == Open + open_close / close_drawer,
100 // +------------------------------------------------------------------------------+
101 Open == Empty + open_close / open_drawer,
102 Open == Paused + open_close / stop_and_open,
103 Open == Stopped + open_close / open_drawer,
104 Open == Playing + open_close / stop_and_open,
105 // +------------------------------------------------------------------------------+
106 Paused == Playing + pause / pause_playback,
107 // +------------------------------------------------------------------------------+
108 Stopped == Playing + stop / stop_playback,
109 Stopped == Paused + stop / stop_playback,
110 Stopped == Empty + cd_detected [good_disk_format&&
111 (event_(cd_type)==Int_<DISK_CD>())]
112 / (store_cd_info,process_(play)),
113 Stopped == Stopped + stop
114 // +------------------------------------------------------------------------------+
115 ),transition_table)
116
117 // create a state machine "on the fly"
118 BOOST_MSM_EUML_DECLARE_STATE_MACHINE(( transition_table, //STT
119 init_ << Empty, // Init State
120 no_action, // Entry
121 no_action, // Exit
122 attributes_ << no_attributes_, // Attributes
123 configure_ << no_configure_, // configuration
124 Log_No_Transition // no_transition handler
125 ),
126 player_) //fsm name
127
128 // choice of back-end
129 typedef msm::back::state_machine<player_> player;
130
131 //
132 // Testing utilities.
133 //
134 static char const* const state_names[] = { "Stopped", "Paused", "Open", "Empty", "Playing" };
pstate(player const & p)135 void pstate(player const& p)
136 {
137 std::cout << " -> " << state_names[p.current_state()[0]] << std::endl;
138 }
139
test()140 void test()
141 {
142 player p;
143 // needed to start the highest-level SM. This will call on_entry and mark the start of the SM
144 p.start();
145 // go to Open, call on_exit on Empty, then action, then on_entry on Open
146 p.process_event(open_close); pstate(p);
147 p.process_event(open_close); pstate(p);
148 // will be rejected, wrong disk type
149 p.process_event(
150 cd_detected("louie, louie",DISK_DVD)); pstate(p);
151 p.process_event(
152 cd_detected("louie, louie",DISK_CD)); pstate(p);
153 // no need to call play as the previous event does it in its action method
154 //p.process_event(play);
155
156 // make transition happen inside it. Player has no idea about this event but it's ok.
157 p.process_event(next_song);pstate(p); //2nd song active
158 p.process_event(next_song);pstate(p);//3rd song active
159 p.process_event(previous_song);pstate(p);//2nd song active
160
161 // at this point, Play is active
162 p.process_event(pause); pstate(p);
163 // go back to Playing
164 // as you see, remembers the original state as end_pause is an history trigger
165 p.process_event(end_pause); pstate(p);
166 p.process_event(pause); pstate(p);
167 p.process_event(stop); pstate(p);
168 // event leading to the same state
169 // no action method called as none is defined in the transition table
170 p.process_event(stop); pstate(p);
171 // test call to no_transition
172 p.process_event(play); pstate(p);
173 }
174 }
175
main()176 int main()
177 {
178 test();
179 return 0;
180 }
181