Amend 883ee9c2, setup required invisible processor

[ardour.git] / libs / ardour / session_process.cc

diff --git a/libs/ardour/session_process.cc b/libs/ardour/session_process.cc
index 104621805447c87c679187141a29c0086b260387..319634499b274f631b71b4777d47261bf6839afb 100644 (file)
--- a/libs/ardour/session_process.cc
+++ b/libs/ardour/session_process.cc
@@ -22,6 +22,9 @@
 #include <algorithm>
 #include <unistd.h>
 
+#include <boost/msm/back/state_machine.hpp>
+#include <boost/msm/front/state_machine_def.hpp>
+
 #include "pbd/error.h"
 #include "pbd/enumwriter.h"
 
@@ -53,6 +56,90 @@ using namespace ARDOUR;
 using namespace PBD;
 using namespace std;
 
+/* state machine */
+namespace msm = boost::msm;
+namespace mpl = boost::mpl;
+
+namespace TransportState
+{
+       /* events */
+       struct play {};
+       struct stop {};
+
+       /* front-end: define the FSM structure  */
+       struct TransportFSM : public msm::front::state_machine_def<TransportFSM>
+       {
+
+               /* FSM states */
+               struct Stopped : public msm::front::state<>
+               {
+                       template <class Event,class FSM> void
+                               on_entry (Event const&, FSM&)
+                               {
+                                       std::cout << "entering: Stopped" << std::endl;
+                               }
+                       template <class Event,class FSM> void
+                               on_exit (Event const&, FSM&)
+                               {
+                                       std::cout << "leaving: Stopped" << std::endl;
+                               }
+               };
+
+               struct Playing : public msm::front::state<>
+               {
+                       template <class Event,class FSM> void
+                               on_entry (Event const&, FSM&)
+                               {
+                                       std::cout << "entering: Playing" << std::endl;
+                               }
+
+                       template <class Event,class FSM> void
+                               on_exit (Event const&, FSM&)
+                               {
+                                       std::cout << "leaving: Playing" << std::endl;
+                               }
+               };
+
+               /* the initial state */
+               typedef Stopped initial_state;
+
+               /* transition actions */
+               void start_playback (play const&)
+               {
+                       std::cout << "player::start_playback\n";
+               }
+
+               void stop_playback (stop const&)
+               {
+                       std::cout << "player::stop_playback\n";
+               }
+
+               typedef TransportFSM _t; // makes transition table cleaner
+
+               struct transition_table : mpl::vector<
+                       //      Start     Event         Next      Action                                 Guard
+                       //    +---------+-------------+---------+---------------------+----------------------+
+                       a_row < Stopped , play        , Playing , &_t::start_playback                        >,
+                        _row < Stopped , stop        , Stopped                                              >,
+                       //    +---------+-------------+---------+---------------------+----------------------+
+                       a_row < Playing , stop        , Stopped , &_t::stop_playback                         >
+                       //    +---------+-------------+---------+---------------------+----------------------+
+                       > {};
+       };
+
+       typedef msm::back::state_machine<TransportFSM> transport_fsm;
+
+       void test()
+       {
+               transport_fsm t;
+               t.start ();
+               t.process_event (play());
+               t.process_event (stop());
+               t.stop();
+       }
+
+};
+
 /** Called by the audio engine when there is work to be done with JACK.
  * @param nframes Number of samples to process.
  */