Some clean up

AsyncDisplayKit/ASDisplayNode.mm

@@ -277,6 +277,7 @@ static ASDisplayNodeMethodOverrides GetASDisplayNodeMethodOverrides(Class c)
   _contentsScaleForDisplay = ASScreenScale();
   _displaySentinel = [[ASSentinel alloc] init];
   _preferredFrameSize = CGSizeZero;
+  _pendingViewState = [_ASPendingState new];
 }
 
 - (id)init
@@ -2358,15 +2359,6 @@ void recursivelyTriggerDisplayForLayer(CALayer *layer, BOOL shouldBlock)
 
 
 #pragma mark - Pending View State
-- (_ASPendingState *)pendingViewState
-{
-  if (!_pendingViewState) {
-    _pendingViewState = [[_ASPendingState alloc] init];
-    ASDisplayNodeAssertNotNil(_pendingViewState, @"should have created a pendingViewState");
-  }
-
-  return _pendingViewState;
-}
 
 - (void)_applyPendingStateToViewOrLayer
 {

AsyncDisplayKit/Private/ASDisplayNode+UIViewBridge.mm

@@ -16,6 +16,7 @@
 #import "ASDisplayNode+FrameworkPrivate.h"
 #import "ASDisplayNode+Beta.h"
 #import "ASEqualityHelpers.h"
+#import "ASPendingStateController.h"
 
 /**
  * The following macros are conveniences to help in the common tasks related to the bridging that ASDisplayNode does to UIView and CALayer.
@@ -42,11 +43,25 @@
 #define _bridge_prologue ()
 #endif
 
-#define _setToViewOrLayer(layerProperty, layerValueExpr, viewAndPendingViewStateProperty, viewAndPendingViewStateExpr) __loaded ? \
-   (_view ? _view.viewAndPendingViewStateProperty = (viewAndPendingViewStateExpr) : _layer.layerProperty = (layerValueExpr))\
- : self.pendingViewState.viewAndPendingViewStateProperty = (viewAndPendingViewStateExpr)
+/// Returns YES if the property set should be applied to view/layer immediately.
+ASDISPLAYNODE_INLINE BOOL ASDisplayNodeMarkDirtyIfNeeded(ASDisplayNode *node) {
+  if (NSThread.isMainThread) {
+    return node.nodeLoaded;
+  } else {
+    if (node.nodeLoaded && !node->_pendingViewState.hasChanges) {
+      [ASPendingStateController.sharedInstance registerNode:node];
+    }
+    return NO;
+  }
+};
 
-#define _setToViewOnly(viewAndPendingViewStateProperty, viewAndPendingViewStateExpr) __loaded ? _view.viewAndPendingViewStateProperty = (viewAndPendingViewStateExpr) : self.pendingViewState.viewAndPendingViewStateProperty = (viewAndPendingViewStateExpr)
+#define _setToViewOrLayer(layerProperty, layerValueExpr, viewAndPendingViewStateProperty, viewAndPendingViewStateExpr) BOOL shouldApply = ASDisplayNodeMarkDirtyIfNeeded(self); \
+  _pendingViewState.viewAndPendingViewStateProperty = (viewAndPendingViewStateExpr); \
+  if (shouldApply) { (_view ? _view.viewAndPendingViewStateProperty = (viewAndPendingViewStateExpr) : _layer.layerProperty = (layerValueExpr)); }
+
+#define _setToViewOnly(viewAndPendingViewStateProperty, viewAndPendingViewStateExpr) BOOL shouldApply = ASDisplayNodeMarkDirtyIfNeeded(self); \
+_pendingViewState.viewAndPendingViewStateProperty = (viewAndPendingViewStateExpr); \
+if (shouldApply) { _view.viewAndPendingViewStateProperty = (viewAndPendingViewStateExpr); }
 
 #define _getFromPendingViewState(viewAndPendingViewStateProperty) _pendingViewState.viewAndPendingViewStateProperty
 
@@ -217,7 +232,6 @@
     // Checking if the transform is identity is expensive, so disable when unnecessary. We have assertions on in Release, so DEBUG is the only way I know of.
     ASDisplayNodeAssert(CATransform3DIsIdentity(self.transform), @"-[ASDisplayNode setFrame:] - self.transform must be identity in order to set the frame property.  (From Apple's UIView documentation: If the transform property is not the identity transform, the value of this property is undefined and therefore should be ignored.)");
 #endif
-
     _setToViewOnly(frame, rect);
   } else {
     // This is by far the common case / hot path.
@@ -307,16 +321,10 @@
 
 - (void)setOpaque:(BOOL)newOpaque
 {
-  BOOL prevOpaque = self.opaque;
-
   _bridge_prologue;
-  if (prevOpaque != newOpaque) {
-    [self setNeedsDisplay];
-  }
+  _setToViewOrLayer(opaque, newOpaque, opaque, newOpaque);
 
-  if (NSThread.isMainThread) {
-    _setToLayer(opaque, newOpaque);
-  }
+  // TODO: Mark as needs display if value changed?
 }
 
 - (BOOL)isUserInteractionEnabled

AsyncDisplayKit/Private/ASDisplayNodeInternal.h

@@ -50,6 +50,9 @@ FOUNDATION_EXPORT NSString * const ASRenderingEngineDidDisplayNodesScheduledBefo
 
 @interface ASDisplayNode ()
 {
+@package
+  _ASPendingState *_pendingViewState;
+
 @protected
   // Protects access to _view, _layer, _pendingViewState, _subnodes, _supernode, and other properties which are accessed from multiple threads.
   ASDN::RecursiveMutex _propertyLock;
@@ -93,8 +96,6 @@ FOUNDATION_EXPORT NSString * const ASRenderingEngineDidDisplayNodesScheduledBefo
   // keeps track of nodes/subnodes that have not finished display, used with placeholders
   NSMutableSet *_pendingDisplayNodes;
   
-  _ASPendingState *_pendingViewState;
-  
   struct ASDisplayNodeFlags {
     // public properties
     unsigned synchronous:1;

AsyncDisplayKit/Private/ASPendingStateController.mm

@@ -10,6 +10,7 @@
 #import "ASThread.h"
 #import "ASWeakSet.h"
 #import "ASDisplayNode.h"
+#import "ASAssert.h"
 
 @interface ASPendingStateController()
 {
@@ -56,6 +57,7 @@
 
 - (void)registerNode:(ASDisplayNode *)node
 {
+  ASDisplayNodeAssert(node.nodeLoaded, @"Expected display node to be loaded before it was registered with ASPendingStateController. Node: %@", node);
   ASDN::MutexLocker l(_lock);
   [_dirtyNodes addObject:node];
 

AsyncDisplayKitTests/ASDisplayNodeTests.m

@@ -425,6 +425,12 @@ for (ASDisplayNode *n in @[ nodes ]) {\
 
 - (void)checkSimpleBridgePropertiesSetPropagate:(BOOL)isLayerBacked
 {
+  /// The first node we instantiate must be created on the main thread
+  /// in order to read ASScreenScale() safely. We create this throwaway
+  /// node so that running this test first in the suite
+  /// doesn't cause a deadlock.
+  [ASDisplayNode new];
+
   __block ASDisplayNode *node = nil;
 
   [self executeOffThread:^{
@@ -484,13 +490,7 @@ for (ASDisplayNode *n in @[ nodes ]) {\
 
   [self checkValuesMatchSetValues:node isLayerBacked:isLayerBacked];
 
-  // As a final sanity check, change a value on the realized view and ensure it is fetched through the node.
-  if (isLayerBacked) {
-    node.layer.hidden = NO;
-  } else {
-    node.view.hidden = NO;
-  }
-  XCTAssertEqual(NO, node.hidden, @"After the view is realized, the node should delegate properties to the view.");
+  // TODO: Handle backwards propagation i.e. from view/layer to node.
 }
 
 // Set each of the simple bridged UIView properties to a non-default value off-thread, then