OSX/CALayer: Revise CALayer 'RunOnMainThread' utilization, avoiding deadlocks

RunOnMainThread(waitUntilDone:=true,..) can deadlock the main-thread if called from AWT-EDT,
since the main-thread may call back to AWT-EDT while injecting a new main-thread task.

This patch revises all RunOnMainThread CALayer usage, resulting in only one required left:
  - OSXUtil.AddCASublayer() w/ waitUntilDone:=false

Hence the CALayer code has no more potential to deadlock main-thread/AWT-EDT.

OSXUtil.AddCASublayer() must be performed on main-thread, otherwise the
CALayer attachment will fail - no visible rendering result.

+++

Note: A good trigger to test this deadlock is to magnify/zoom
      the OSX desktop (click background + ctrl-mouse_wheel)
      before running some unit tests.

      TestGLCanvasAWTActionDeadlock01AWT and TestAddRemove02GLWindowNewtCanvasAWT
      also have the potential to trigger the mentioned deadlock.

1 files changed, 12 insertions, 18 deletions

diff --git a/src/jogl/classes/jogamp/opengl/macosx/cgl/MacOSXCGLContext.java b/src/jogl/classes/jogamp/opengl/macosx/cgl/MacOSXCGLContext.java
index a03850043..9e6085030 100644
--- a/src/jogl/classes/jogamp/opengl/macosx/cgl/MacOSXCGLContext.java
+++ b/src/jogl/classes/jogamp/opengl/macosx/cgl/MacOSXCGLContext.java
@@ -676,30 +676,24 @@ public abstract class MacOSXCGLContext extends GLContextImpl
                   }
                    
                   /**
-                   * Perform NSOpenGLLayer creation and attaching on main-thread,
-                   * hence release the lock on our context - which will be used to 
-                   * create a shared context within NSOpenGLLayer.
+                   * NSOpenGLLayer creation is performed on the current thread,
+                   * which immediately creates it's own GL ctx sharing this ctx
+                   * not causing any locking issues.
+                   * 
+                   * Subsequent attaching is performed on main-thread w/o blocking.
+                   * 
+                   * This is a lock free operation.
                    */
                   final long cglCtx = CGL.getCGLContext(ctx);
                   if(0 == cglCtx) {
                       throw new InternalError("Null CGLContext for: "+this);
                   }
-                  final boolean ctxUnlocked = CGL.kCGLNoError == CGL.CGLUnlockContext(cglCtx);
-                  try {                  
-                      nsOpenGLLayer = CGL.createNSOpenGLLayer(ctx, gl3ShaderProgramName, pixelFormat, pbufferHandle, texID, chosenCaps.isBackgroundOpaque(), lastWidth, lastHeight);
-                      if (DEBUG) {
-                          System.err.println("NS create nsOpenGLLayer "+toHexString(nsOpenGLLayer)+" w/ pbuffer "+toHexString(pbufferHandle)+", texID "+texID+", texSize "+lastWidth+"x"+lastHeight+", "+drawable);
-                      }
-                      backingLayerHost.attachSurfaceLayer(nsOpenGLLayer);
-                      setSwapInterval(1); // enabled per default in layered surface
-                  } finally {
-                      if( ctxUnlocked ) {
-                          if( CGL.kCGLNoError != CGL.CGLLockContext(cglCtx) ) {
-                              throw new InternalError("Could not re-lock CGLContext for: "+this);
-                          }
-                      }
+                  nsOpenGLLayer = CGL.createNSOpenGLLayer(ctx, gl3ShaderProgramName, pixelFormat, pbufferHandle, texID, chosenCaps.isBackgroundOpaque(), lastWidth, lastHeight);
+                  if (DEBUG) {
+                      System.err.println("NS create nsOpenGLLayer "+toHexString(nsOpenGLLayer)+" w/ pbuffer "+toHexString(pbufferHandle)+", texID "+texID+", texSize "+lastWidth+"x"+lastHeight+", "+drawable);
                   }
-                  backingLayerHost.layoutSurfaceLayer();
+                  backingLayerHost.attachSurfaceLayer(nsOpenGLLayer);
+                  setSwapInterval(1); // enabled per default in layered surface
               } else {
                   lastWidth = drawable.getWidth();
                   lastHeight = drawable.getHeight();