Fix destroy race conditions

Author: EddyGharbi

src/window-osx.h

@@ -30,6 +30,7 @@
 #include <map>
 #include <iostream>
 #include <thread>
+#include <mutex>
 
 @interface WindowImplObj : NSObject
 @end
@@ -42,16 +43,18 @@ struct OpenGLData {
     GLuint mPosAttribute;
     GLuint mVertexbuffer;
     IOSurfaceRef surface = NULL;
+    std::thread* thread;
+    std::mutex mtx;
+    bool stop = false;
 };
 
 @interface OpenGLView: NSView
 @property (atomic) OpenGLData* glData;
 @end
 
 struct WindowInfo {
-    bool stop = false;
-    std::thread* thread;
     OpenGLView* view;
+    bool destroyed = false;
 };
 
 std::map<void*, void*> windows; // <NSView* parent, WindowInfo* wi>

src/window-osx.mm

@@ -20,10 +20,11 @@
 
 void renderFrames(WindowInfo* wi)
 {
-  while (!wi->stop) {
+  while (!wi->view.glData->stop) {
     std::this_thread::sleep_for(std::chrono::milliseconds(16));
-    dispatch_sync(dispatch_get_main_queue(), ^{
-      if (!wi->stop) {
+
+    dispatch_async(dispatch_get_main_queue(), ^{
+      if (!wi->destroyed && !wi->view.glData->stop) {
         wi->view.needsDisplay = YES;
       }
     });
@@ -120,9 +121,6 @@ - (id)initWithFrame:(NSRect)aFrame
 
 - (void)dealloc
 {
-  [self _cleanupGL];
-  [NSOpenGLContext clearCurrentContext];
-  [self.glData->mContext release];
   [super dealloc];
 }
 
@@ -275,9 +273,11 @@ - (void)_surfaceNeedsUpdate:(NSNotification*)notification
 
 - (void)drawRect:(NSRect)aRect
 {
-  if (!self.glData->surface)
+  if (!self.glData->surface || self.glData->stop)
     return;
 
+  self.glData->mtx.lock();
+
   CGLTexImageIOSurface2D([self.glData->mContext CGLContextObj],
                         GL_TEXTURE_RECTANGLE_ARB, GL_RGBA,
                         IOSurfaceGetWidth(self.glData->surface),
@@ -341,6 +341,7 @@ - (void)drawRect:(NSRect)aRect
   gl_success("glDisableVertexAttribArray");
 
   [self.glData->mContext flushBuffer];
+  self.glData->mtx.unlock();
 }
 
 - (BOOL)wantsBestResolutionOpenGLSurface
@@ -398,7 +399,18 @@ @implementation WindowImplObj
     return;
 
   WindowInfo* wi = reinterpret_cast<WindowInfo*>(it->second);
-  wi->stop = true;
+  wi->view.glData->mtx.lock();
+  wi->view.glData->stop = true;
+
+  if (wi->view.glData->thread->joinable())
+    wi->view.glData->thread->join();
+
+  [self _cleanupGL];
+  [NSOpenGLContext clearCurrentContext];
+  [wi->view.glData->mContext release];
+  wi->destroyed = true;
+  wi->view.glData->mtx.unlock();
+
   [wi->view removeFromSuperview];
   CFRelease(wi->view);
 
@@ -418,8 +430,8 @@ @implementation WindowImplObj
   if (!wi->view.glData->surface)
     return;
 
-  wi->stop = false;
-  wi->thread = new std::thread(renderFrames, wi);
+  wi->view.glData->stop = false;
+  wi->view.glData->thread = new std::thread(renderFrames, wi);
 
   [wi->view setFrameSize:NSMakeSize(IOSurfaceGetWidth(wi->view.glData->surface),
                                   IOSurfaceGetHeight(wi->view.glData->surface))];