fix issues with recording while synced to JACK (non-pure-virtual method added to AudioBackend) and remove pause() from AudioEngine/AudioBackend APIs

libs/ardour/ardour/audio_backend.h

@@ -327,20 +327,6 @@ class AudioBackend : public PortEngine {
      */
     virtual int stop () = 0;
 
-    /** Temporarily cease using the device named in the most recent call to set_parameters().
-     *
-     * If the function is successfully called, no subsequent calls to the
-     * process_callback() of @param engine will be made after the function
-     * returns, until start() is called again.
-     * 
-     * The backend will retain its existing parameter configuration after a successful
-     * return, and does NOT require any calls to set hardware parameters before it can be
-     * start()-ed again. 
-     *
-     * Return zero if successful, 1 if the device is not in use, negative values on error
-     */
-    virtual int pause () = 0;
-
     /** While remaining connected to the device, and without changing its
      * configuration, start (or stop) calling the process_callback() of @param engine
      * without waiting for the device. Once process_callback() has returned, it
@@ -478,6 +464,21 @@ class AudioBackend : public PortEngine {
 
     virtual void update_latencies () = 0;
 
+    /** Set @param speed and @param position to the current speed and position
+     * indicated by some transport sync signal.  Return whether the current
+     * transport state is pending, or finalized.
+     *
+     * Derived classes only need implement this if they provide some way to
+     * sync to a transport sync signal (e.g. Sony 9 Pin) that is not
+     * handled by Ardour itself (LTC and MTC are both handled by Ardour).
+     * The canonical example is JACK Transport.
+     */
+     virtual bool speed_and_position (double& speed, framepos_t& position) {
+	     speed = 0.0;
+	     position = 0;
+	     return false;
+     }
+
   protected:
     AudioEngine&          engine;
 };

libs/ardour/ardour/audioengine.h

@@ -85,7 +85,6 @@ public:
 
     int            start (bool for_latency_measurement=false);
     int            stop (bool for_latency_measurement=false);
-    int            pause ();
     int            freewheel (bool start_stop);
     float          get_cpu_load() const ;
     void           transport_start ();

libs/ardour/audioengine.cc

@@ -662,23 +662,6 @@ AudioEngine::stop (bool for_latency)
 	return 0;
 }
 
-int
-AudioEngine::pause ()
-{
-	if (!_backend) {
-		return 0;
-	}
-	
-	if (_backend->pause ()) {
-		return -1;
-	}
-
-	_running = false;
-	
-	Stopped(); /* EMIT SIGNAL */
-	return 0;
-}
-
 int
 AudioEngine::freewheel (bool start_stop)
 {

libs/ardour/engine_slave.cc

@@ -21,6 +21,7 @@
 #include <cerrno>
 
 #include "ardour/audioengine.h"
+#include "ardour/audio_backend.h"
 #include "ardour/slave.h"
 
 using namespace std;
@@ -54,26 +55,13 @@ Engine_Slave::ok() const
 bool
 Engine_Slave::speed_and_position (double& sp, framepos_t& position)
 {
-	switch (engine.transport_state()) {
-	case TransportStopped:
-		speed = 0;
+	boost::shared_ptr<AudioBackend> backend = engine.current_backend();
+
+	if (backend) {
+		_starting = backend->speed_and_position (sp, position);
+	} else {
 		_starting = false;
-		break;
-	case TransportRolling:
-		speed = 1.0;
-		_starting = false;
-		break;
-	case TransportLooping:
-		speed = 1.0;
-		_starting = false;
-		break;
-	case TransportStarting:
-		_starting = true;
-		// don't adjust speed here, just leave it as it was
-		break;
 	}
 	
-	sp = speed;
-	position = engine.transport_frame();
 	return true;
 }

libs/backends/jack/jack_audiobackend.cc

@@ -581,18 +581,6 @@ JACKAudioBackend::stop ()
 	return 0;
 }
 
-int
-JACKAudioBackend::pause ()
-{
-	GET_PRIVATE_JACK_POINTER_RET (_priv_jack, -1);
-
-	if (_priv_jack) {
-		jack_deactivate (_priv_jack);
-	}
-
-	return 0;
-}
-
 int
 JACKAudioBackend::freewheel (bool onoff)
 {
@@ -1131,3 +1119,46 @@ JACKAudioBackend::set_midi_option (const string& opt)
 	_target_midi_option = opt;
 	return 0;
 }
+
+bool
+JACKAudioBackend::speed_and_position (double& speed, framepos_t& position)
+{
+	jack_position_t pos;
+	jack_transport_state_t state;
+	bool starting;
+
+	/* this won't be called if the port engine in use is not JACK, so we do 
+	   not have to worry about the type of PortEngine::private_handle()
+	*/
+
+	speed = 0;
+	position = 0;
+
+	GET_PRIVATE_JACK_POINTER_RET (_priv_jack, true);
+
+	state = jack_transport_query (_priv_jack, &pos);
+
+	switch (state) {
+	case JackTransportStopped:
+		speed = 0;
+		starting = false;
+		break;
+	case JackTransportRolling:
+		speed = 1.0;
+		starting = false;
+		break;
+	case JackTransportLooping:
+		speed = 1.0;
+		starting = false;
+		break;
+	case JackTransportStarting:
+		starting = true;
+		// don't adjust speed here, just leave it as it was
+		break;
+	default:
+		std::cerr << "WARNING: Unknown JACK transport state: " << state << std::endl;
+	}
+
+	position = pos.frame;
+	return starting;
+}

libs/backends/jack/jack_audiobackend.h

@@ -91,7 +91,6 @@ class JACKAudioBackend : public AudioBackend {
 
     int _start (bool for_latency_measurement);
     int stop ();
-    int pause ();
     int freewheel (bool);
 
     float cpu_load() const;
@@ -183,6 +182,10 @@ class JACKAudioBackend : public AudioBackend {
 
     void* get_buffer (PortHandle, pframes_t);
 
+    /* transport sync */
+
+    bool speed_and_position (double& sp, framepos_t& pos);
+
   private:
     boost::shared_ptr<JackConnection>  _jack_connection;
     bool            _running;

libs/backends/jack/jack_session.cc

@@ -23,6 +23,7 @@
 #include <glibmm/miscutils.h>
 
 #include <jack/jack.h>
+#include <jack/transport.h>
 
 #include "ardour/audioengine.h"
 #include "ardour/filename_extensions.h"