From 38d81c394f1b0177aacc66b3979323f0310feaf6 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Sun, 22 Mar 2020 21:11:04 -0400
Subject: [PATCH] Switches OSAtomics to stdatomics. The former were deprecated
 by macOS 10.12.

---
 OSBindings/Mac/Clock Signal/Views/CSOpenGLView.m | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/OSBindings/Mac/Clock Signal/Views/CSOpenGLView.m b/OSBindings/Mac/Clock Signal/Views/CSOpenGLView.m
index 09c1b7e9f..a30510de7 100644
--- a/OSBindings/Mac/Clock Signal/Views/CSOpenGLView.m	
+++ b/OSBindings/Mac/Clock Signal/Views/CSOpenGLView.m	
@@ -11,6 +11,8 @@
 @import CoreVideo;
 @import GLKit;
 
+#include <stdatomic.h>
+
 @interface CSOpenGLView () <NSDraggingDestination, CSApplicationEventDelegate>
 @end
 
@@ -23,13 +25,16 @@
 	NSTimer *_mouseHideTimer;
 	BOOL _mouseIsCaptured;
 
-	volatile int32_t _isDrawingFlag;
+	atomic_int _isDrawingFlag;
 	BOOL _isInvalid;
 }
 
 - (void)prepareOpenGL {
 	[super prepareOpenGL];
 
+	// Prepare the atomic int.
+	atomic_init(&_isDrawingFlag, 0);
+
 	// Set the clear colour.
 	[self.openGLContext makeCurrentContext];
 	glClearColor(0.0, 0.0, 0.0, 1.0);
@@ -71,7 +76,7 @@ static CVReturn DisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeSt
 	});
 
 	// Ensure _isDrawingFlag has value 1 when drawing, 0 otherwise.
-	OSAtomicIncrement32(&view->_isDrawingFlag);
+	atomic_store(&view->_isDrawingFlag, 1);
 
 	[view.displayLinkDelegate openGLViewDisplayLinkDidFire:view now:now outputTime:outputTime];
 	/*
@@ -84,7 +89,7 @@ static CVReturn DisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeSt
 		access the display link itself as part of -drawAtTime:frequency:.
 	*/
 
-	OSAtomicDecrement32(&view->_isDrawingFlag);
+	atomic_store(&view->_isDrawingFlag, 0);
 
 	return kCVReturnSuccess;
 }
@@ -143,7 +148,10 @@ static CVReturn DisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeSt
 	usleep((useconds_t)ceil(duration * 1000000.0));
 
 	// Spin until _isDrawingFlag is 0 (and leave it as 0).
-	while(!OSAtomicCompareAndSwap32(0, 0, &_isDrawingFlag));
+	int expected_value = 0;
+	while(!atomic_compare_exchange_weak(&_isDrawingFlag, &expected_value, 0)) {
+		expected_value = 0;
+	}
 }
 
 - (void)dealloc {