Make InternalReturns collect their sends' data on the return's ::run(), rather than sends merging data with the InternalReturn on their ::run(). This makes internal send/return thread-safe so that N routes can send to 1 whilst they are being run in parallel process threads.

git-svn-id: svn://localhost/ardour2/branches/3.0@8904 d708f5d6-7413-0410-9779-e7cbd77b26cf

6 files changed, 44 insertions, 53 deletions

diff --git a/libs/ardour/ardour/internal_return.h b/libs/ardour/ardour/internal_return.h
index 41d09b2805..17688b892f 100644
--- a/libs/ardour/ardour/internal_return.h
+++ b/libs/ardour/ardour/internal_return.h
@@ -27,12 +27,14 @@
 
 namespace ARDOUR {
 
+class InternalSend;	
+
 class InternalReturn : public Return
 {
   public:
 	InternalReturn (Session&);
 
-XMLNode& state(bool full);
+	XMLNode& state(bool full);
 	XMLNode& get_state(void);
 	int set_state(const XMLNode&, int version);
 
@@ -41,14 +43,16 @@ XMLNode& state(bool full);
 	bool can_support_io_configuration (const ChanCount& in, ChanCount& out) const;
 	int  set_block_size (pframes_t);
 
-	BufferSet* get_buffers();
-	void release_buffers();
-
+	void add_send (InternalSend *);
+	void remove_send (InternalSend *);
+	
 	static PBD::Signal1<void, pframes_t> CycleStart;
 
   private:
 	BufferSet buffers;
-	gint user_count; /* atomic */
+	/** sends that we are receiving data from */
+	std::list<InternalSend*> _sends;
+	
 	void allocate_buffers (pframes_t);
 	void cycle_start (pframes_t);
 };
diff --git a/libs/ardour/ardour/internal_send.h b/libs/ardour/ardour/internal_send.h
index 53c6686887..95fec708ed 100644
--- a/libs/ardour/ardour/internal_send.h
+++ b/libs/ardour/ardour/internal_send.h
@@ -48,9 +48,12 @@ class InternalSend : public Send
 	boost::shared_ptr<Route> target_route() const { return _send_to; }
 	const PBD::ID& target_id() const { return _send_to_id; }
 
+	BufferSet const & get_buffers () const {
+		return mixbufs;
+	}
+
   private:
-	BufferSet  mixbufs;
-	BufferSet* target;
+	BufferSet mixbufs;
 	boost::shared_ptr<Route> _send_to;
 	PBD::ID _send_to_id;
 	PBD::ScopedConnection connect_c;
diff --git a/libs/ardour/ardour/route.h b/libs/ardour/ardour/route.h
index defcc2c5c2..9b2ed47c76 100644
--- a/libs/ardour/ardour/route.h
+++ b/libs/ardour/ardour/route.h
@@ -63,6 +63,7 @@ class InternalReturn;
 class MonitorProcessor;
 class Pannable;
 class CapturingProcessor;
+class InternalSend;
 
 class Route : public SessionObject, public Automatable, public RouteGroupMember, public GraphNode
 {
@@ -218,8 +219,8 @@ class Route : public SessionObject, public Automatable, public RouteGroupMember,
 	boost::shared_ptr<MonitorProcessor> monitor_control() const { return _monitor_control; }
 	boost::shared_ptr<Send>             internal_send_for (boost::shared_ptr<const Route> target) const;
 	void add_internal_return ();
-	BufferSet* get_return_buffer () const;
-	void release_return_buffer () const;
+	void add_send_to_internal_return (InternalSend *);
+	void remove_send_from_internal_return (InternalSend *);
 	void listen_position_changed ();
 	boost::shared_ptr<CapturingProcessor> add_export_point(/* Add some argument for placement later */);
 
diff --git a/libs/ardour/internal_return.cc b/libs/ardour/internal_return.cc
index 8e058b69b1..22dafbd6dc 100644
--- a/libs/ardour/internal_return.cc
+++ b/libs/ardour/internal_return.cc
@@ -23,6 +23,7 @@
 #include "ardour/internal_return.h"
 #include "ardour/mute_master.h"
 #include "ardour/session.h"
+#include "ardour/internal_send.h"
 
 using namespace std;
 using namespace ARDOUR;
@@ -31,7 +32,6 @@ PBD::Signal1<void, pframes_t> InternalReturn::CycleStart;
 
 InternalReturn::InternalReturn (Session& s)
 	: Return (s, true)
-	, user_count (0)
 {
 	CycleStart.connect_same_thread (*this, boost::bind (&InternalReturn::cycle_start, this, _1));
         _display_to_user = false;
@@ -44,14 +44,14 @@ InternalReturn::run (BufferSet& bufs, framepos_t /*start_frame*/, framepos_t /*e
 		return;
 	}
 
-	/* no lock here, just atomic fetch */
+	/* _sends is only modified with the process lock held, so this is ok, I think */
 
-	if (g_atomic_int_get(&user_count) == 0) {
-		/* nothing to do - nobody is feeding us anything */
-		return;
+	for (list<InternalSend*>::iterator i = _sends.begin(); i != _sends.end(); ++i) {
+		if ((*i)->active ()) {
+			bufs.merge_from ((*i)->get_buffers(), nframes);
+		}
 	}
 
-	bufs.merge_from (buffers, nframes);
 	_active = _pending_active;
 }
 
@@ -77,34 +77,26 @@ InternalReturn::allocate_buffers (pframes_t nframes)
 	buffers.set_count (_configured_input);
 }
 
-BufferSet*
-InternalReturn::get_buffers ()
+void
+InternalReturn::add_send (InternalSend* send)
 {
 	Glib::Mutex::Lock lm (_session.engine().process_lock());
-	/* use of g_atomic here is just for code consistency - its protected by the lock
-	   for writing.
-	*/
-	g_atomic_int_inc (&user_count);
-	return &buffers;
+	_sends.push_back (send);
 }
 
 void
-InternalReturn::release_buffers ()
+InternalReturn::remove_send (InternalSend* send)
 {
 	Glib::Mutex::Lock lm (_session.engine().process_lock());
-	if (user_count) {
-		/* use of g_atomic here is just for code consistency - its protected by the lock
-		   for writing.
-		*/
-		(void) g_atomic_int_dec_and_test (&user_count);
-	}
+	_sends.remove (send);
+	/* XXX: do we need to remove the connection to this send from _send_drop_references_connections ? */
 }
 
 void
 InternalReturn::cycle_start (pframes_t nframes)
 {
 	/* called from process cycle - no lock necessary */
-	if (user_count) {
+	if (!_sends.empty ()) {
 		/* don't bother with this if nobody is going to feed us anything */
 		buffers.silence (nframes, 0);
 	}
@@ -138,3 +130,4 @@ InternalReturn::can_support_io_configuration (const ChanCount& in, ChanCount& ou
 	return true;
 }
 
+	
diff --git a/libs/ardour/internal_send.cc b/libs/ardour/internal_send.cc
index 4c3b385304..bdfcf6d249 100644
--- a/libs/ardour/internal_send.cc
+++ b/libs/ardour/internal_send.cc
@@ -34,7 +34,6 @@ using namespace std;
 
 InternalSend::InternalSend (Session& s, boost::shared_ptr<Pannable> p, boost::shared_ptr<MuteMaster> mm, boost::shared_ptr<Route> sendto, Delivery::Role role)
 	: Send (s, p, mm, role)
-	, target (0)
 {
         if (sendto) {
                 if (use_target (sendto)) {
@@ -46,18 +45,20 @@ InternalSend::InternalSend (Session& s, boost::shared_ptr<Pannable> p, boost::sh
 InternalSend::~InternalSend ()
 {
 	if (_send_to) {
-		_send_to->release_return_buffer ();
+		_send_to->remove_send_from_internal_return (this);
 	}
 }
 
 int
 InternalSend::use_target (boost::shared_ptr<Route> sendto)
 {
+	if (_send_to) {
+		_send_to->remove_send_from_internal_return (this);
+	}
+	
         _send_to = sendto;
 
-        if ((target = _send_to->get_return_buffer ()) == 0) {
-                return -1;
-        }
+        _send_to->add_send_to_internal_return (this);
         
         set_name (sendto->name());
         _send_to_id = _send_to->id();
@@ -74,7 +75,6 @@ InternalSend::use_target (boost::shared_ptr<Route> sendto)
 void
 InternalSend::send_to_going_away ()
 {
-	target = 0;
         target_connections.drop_connections ();
 	_send_to.reset ();
 	_send_to_id = "0";
@@ -83,7 +83,7 @@ InternalSend::send_to_going_away ()
 void
 InternalSend::run (BufferSet& bufs, framepos_t start_frame, framepos_t end_frame, pframes_t nframes, bool)
 {
-	if ((!_active && !_pending_active) || !target || !_send_to) {
+	if ((!_active && !_pending_active) || !_send_to) {
 		_meter->reset ();
 		return;
 	}
@@ -138,9 +138,7 @@ InternalSend::run (BufferSet& bufs, framepos_t start_frame, framepos_t end_frame
 		}
 	}
 
-	/* deliver to target */
-
-	target->merge_from (mixbufs, nframes);
+	/* target will pick up our output when it is ready */
 
   out:
 	_active = _pending_active;
@@ -150,11 +148,6 @@ int
 InternalSend::set_block_size (pframes_t nframes)
 {
 	mixbufs.ensure_buffers (_configured_input, nframes);
-
-	/* ensure that our target can cope with us merging this many frames to it */
-	if (target) {
-		target->ensure_buffers (_configured_input, nframes);
-	}
         return 0;
 }
 
diff --git a/libs/ardour/route.cc b/libs/ardour/route.cc
index 56fc090576..cb2f231def 100644
--- a/libs/ardour/route.cc
+++ b/libs/ardour/route.cc
@@ -2465,8 +2465,8 @@ Route::add_internal_return ()
 	}
 }
 
-BufferSet*
-Route::get_return_buffer () const
+void
+Route::add_send_to_internal_return (InternalSend* send)
 {
 	Glib::RWLock::ReaderLock rm (_processor_lock);
 
@@ -2474,16 +2474,13 @@ Route::get_return_buffer () const
 		boost::shared_ptr<InternalReturn> d = boost::dynamic_pointer_cast<InternalReturn>(*x);
 
 		if (d) {
-			BufferSet* bs = d->get_buffers ();
-			return bs;
+			return d->add_send (send);
 		}
 	}
-
-	return 0;
 }
 
 void
-Route::release_return_buffer () const
+Route::remove_send_from_internal_return (InternalSend* send)
 {
 	Glib::RWLock::ReaderLock rm (_processor_lock);
 
@@ -2491,7 +2488,7 @@ Route::release_return_buffer () const
 		boost::shared_ptr<InternalReturn> d = boost::dynamic_pointer_cast<InternalReturn>(*x);
 
 		if (d) {
-			return d->release_buffers ();
+			return d->remove_send (send);
 		}
 	}
 }