From 9c550c594acc52a028873889a9b847acfe160fc2 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Wed, 9 Nov 2016 21:17:50 -0500
Subject: [PATCH] Moved audio work back into its own thread, but this time it
 queues up an all happens only upon a flush. Hopefully to resolve
 synchronisation cost concerns.

---
 Machines/Oric/Oric.cpp |  1 +
 Outputs/Speaker.hpp    | 30 +++++++++++++++++++++++-------
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/Machines/Oric/Oric.cpp b/Machines/Oric/Oric.cpp
index a3a5b7b3c..fc06421a8 100644
--- a/Machines/Oric/Oric.cpp
+++ b/Machines/Oric/Oric.cpp
@@ -213,6 +213,7 @@ uint8_t Machine::VIA::get_port_input(Port port)
 void Machine::VIA::synchronise()
 {
 	ay8910->run_for_cycles(_cycles_since_ay_update);
+	ay8910->flush();
 	_cycles_since_ay_update = 0;
 }
 
diff --git a/Outputs/Speaker.hpp b/Outputs/Speaker.hpp
index bceeb1d5b..f2830908f 100644
--- a/Outputs/Speaker.hpp
+++ b/Outputs/Speaker.hpp
@@ -12,6 +12,10 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <time.h>
+
+#include <memory>
+#include <list>
+
 #include "../SignalProcessing/Stepper.hpp"
 #include "../SignalProcessing/FIRFilter.hpp"
 #include "../Concurrency/AsyncTaskQueue.hpp"
@@ -87,16 +91,28 @@ class Speaker {
 
 		Speaker() : _buffer_in_progress_pointer(0), _requested_number_of_taps(0), _high_frequency_cut_off(-1.0), _queue(new Concurrency::AsyncTaskQueue) {}
 
+		/*!
+			Ensures any deferred processing occurs now.
+		*/
+		void flush()
+		{
+			std::shared_ptr<std::list<std::function<void(void)>>> queued_functions = _queued_functions;
+			_queued_functions.reset();
+			_queue->enqueue([queued_functions] {
+				for(auto function : *queued_functions)
+				{
+					function();
+				}
+			});
+		}
+
 	protected:
 		void enqueue(std::function<void(void)> function)
 		{
-			function();
-//			_queue->enqueue(function);
-		}
-		void flush()
-		{
-//			_queue->flush();
+			if(!_queued_functions) _queued_functions.reset(new std::list<std::function<void(void)>>);
+			_queued_functions->push_back(function);
 		}
+		std::shared_ptr<std::list<std::function<void(void)>>> _queued_functions;
 
 		std::unique_ptr<int16_t> _buffer_in_progress;
 		float _high_frequency_cut_off;
@@ -137,7 +153,7 @@ template <class T> class Filter: public Speaker {
 	public:
 		~Filter()
 		{
-			flush();
+			_queue->flush();
 		}
 
 		void run_for_cycles(unsigned int input_cycles)