redesign cross-thread registration/signalling system

This new design will work even when threads that need to receive
messages from RT threads are created *after* the RT threads. The
existing design would fail because the RT thread(s) would never
be known the later created threads, and so signals emitted by the
RT thread and causing call_slot() in the receiver would end up
being enqueued using a lock-protected list. The new design ensures
that communication always uses a lock-free FIFO instead

1 files changed, 15 insertions, 4 deletions

diff --git a/libs/surfaces/faderport/faderport.cc b/libs/surfaces/faderport/faderport.cc
index 135943d34f..f10f70dce5 100644
--- a/libs/surfaces/faderport/faderport.cc
+++ b/libs/surfaces/faderport/faderport.cc
@@ -66,7 +66,7 @@ using namespace std;
 
 FaderPort::FaderPort (Session& s)
 	: ControlProtocol (s, _("Faderport"))
-	, AbstractUI<FaderPortRequest> ("faderport")
+	, AbstractUI<FaderPortRequest> (name())
 	, gui (0)
 	, connection_state (ConnectionState (0))
 	, _device_active (false)
@@ -210,6 +210,17 @@ FaderPort::~FaderPort ()
 	tear_down_gui ();
 }
 
+void*
+FaderPort::request_factory (uint32_t num_requests)
+{
+	/* AbstractUI<T>::request_buffer_factory() is a template method only
+	   instantiated in this source module. To provide something visible for
+	   use in the interface/descriptor, we have this static method that is
+	   template-free.
+	*/
+	return request_buffer_factory (num_requests);
+}
+
 void
 FaderPort::start_midi_handling ()
 {
@@ -267,10 +278,10 @@ FaderPort::thread_init ()
 {
 	struct sched_param rtparam;
 
-	pthread_set_name (X_("FaderPort"));
+	pthread_set_name (event_loop_name().c_str());
 
-	PBD::notify_gui_about_thread_creation (X_("gui"), pthread_self(), X_("FaderPort"), 2048);
-	ARDOUR::SessionEvent::create_per_thread_pool (X_("FaderPort"), 128);
+	PBD::notify_event_loops_about_thread_creation (pthread_self(), event_loop_name(), 2048);
+	ARDOUR::SessionEvent::create_per_thread_pool (event_loop_name(), 128);
 
 	memset (&rtparam, 0, sizeof (rtparam));
 	rtparam.sched_priority = 9; /* XXX should be relative to audio (JACK) thread */