a putatively better approach to cleaning up ports at session closing

git-svn-id: svn://localhost/ardour2/branches/3.0@12807 d708f5d6-7413-0410-9779-e7cbd77b26cf

4 files changed, 38 insertions, 11 deletions

diff --git a/libs/ardour/ardour/port.h b/libs/ardour/ardour/port.h
index 37101950d5..e225117d94 100644
--- a/libs/ardour/ardour/port.h
+++ b/libs/ardour/ardour/port.h
@@ -126,6 +126,7 @@ public:
 
 	PBD::Signal1<void,bool> MonitorInputChanged;
 	static PBD::Signal2<void,boost::shared_ptr<Port>,boost::shared_ptr<Port> > PostDisconnect;
+	static PBD::Signal0<void> PortDrop;
 
 	static void set_cycle_framecnt (pframes_t n) {
 		_cycle_nframes = n;
@@ -167,6 +168,8 @@ private:
 	*/
 	std::set<std::string> _connections;
 
+       void drop ();
+       PBD::ScopedConnection drop_connection;
 };
 
 }
diff --git a/libs/ardour/audioengine.cc b/libs/ardour/audioengine.cc
index 26f8311c8d..5642db8932 100644
--- a/libs/ardour/audioengine.cc
+++ b/libs/ardour/audioengine.cc
@@ -479,6 +479,21 @@ AudioEngine::process_callback (pframes_t nframes)
 		/* perform the actual session removal */
 		_session = 0;
 		session_remove_pending = false;
+
+		/* pump one cycle of silence into the ports
+		   before the session tears them all down
+		   (asynchronously).
+		*/
+
+		boost::shared_ptr<Ports> p = ports.reader();
+		
+		for (Ports::iterator i = p->begin(); i != p->end(); ++i) {
+			
+			if (i->second->sends_output()) {
+				i->second->get_buffer (nframes).silence (nframes);
+			}
+		}
+
 		session_removed.signal();
 	}
 
@@ -486,15 +501,6 @@ AudioEngine::process_callback (pframes_t nframes)
 		if (!_freewheeling) {
 			MIDI::Manager::instance()->cycle_start(nframes);
 			MIDI::Manager::instance()->cycle_end();
-
-			boost::shared_ptr<Ports> p = ports.reader();
-			
-			for (Ports::iterator i = p->begin(); i != p->end(); ++i) {
-				
-				if (i->second->sends_output()) {
-					i->second->get_buffer (nframes).silence (nframes);
-				}
-			}
 		}
 
 		_processed_frames = next_processed_frames;
diff --git a/libs/ardour/port.cc b/libs/ardour/port.cc
index b0c4b43c06..3473b73617 100644
--- a/libs/ardour/port.cc
+++ b/libs/ardour/port.cc
@@ -38,6 +38,7 @@ using namespace ARDOUR;
 using namespace PBD;
 
 PBD::Signal2<void,boost::shared_ptr<Port>, boost::shared_ptr<Port> > Port::PostDisconnect;
+PBD::Signal0<void> Port::PortDrop;
 
 AudioEngine* Port::_engine = 0;
 bool         Port::_connecting_blocked = false;
@@ -71,13 +72,24 @@ Port::Port (std::string const & n, DataType t, Flags f)
 		cerr << "Failed to register JACK port \"" << _name << "\", reason is unknown from here\n";
 		throw failed_constructor ();
 	}
+
+	PortDrop.connect_same_thread (drop_connection, boost::bind (&Port::drop, this));
 }
 
 /** Port destructor */
 Port::~Port ()
 {
-	if (_engine->jack ()) {
-		jack_port_unregister (_engine->jack (), _jack_port);
+	drop ();
+}
+
+void
+Port::drop ()
+{
+	if (_jack_port) {
+		if (_engine->jack ()) {
+			jack_port_unregister (_engine->jack (), _jack_port);
+		}
+		_jack_port = 0;
 	}
 }
 
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index 9eb4c223d0..5758130092 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -234,6 +234,12 @@ Session::destroy ()
 
 	_engine.remove_session ();
 
+	/* deregister all ports - there will be no process or any other
+	 * callbacks from the engine any more.
+	 */
+
+	Port::PortDrop (); /* EMIT SIGNAL */
+
 	/* clear history so that no references to objects are held any more */
 
 	_history.clear ();