[ASDisplayNode] Convert isSynchronous to an Objective-C atomic BOOL.

Source/ASDisplayNode.h

@@ -217,8 +217,7 @@ extern NSInteger const ASDefaultDrawingPriority;
  *
  * @return NO if the node wraps a _ASDisplayView, YES otherwise.
  */
-@property (nonatomic, readonly, assign, getter=isSynchronous) BOOL synchronous;
-
+@property (atomic, readonly, assign, getter=isSynchronous) BOOL synchronous;
 
 /** @name Getting view and layer */
 

Source/ASDisplayNode.mm

@@ -100,9 +100,9 @@ BOOL ASDisplayNodeSubclassOverridesSelector(Class subclass, SEL selector)
 
 // For classes like ASTableNode, ASCollectionNode, ASScrollNode and similar - we have to be sure to set certain properties
 // like setFrame: and setBackgroundColor: directly to the UIView and not apply it to the layer only.
-BOOL ASDisplayNodeNeedsSpecialPropertiesHandlingForFlags(ASDisplayNodeFlags flags)
+BOOL ASDisplayNodeNeedsSpecialPropertiesHandling(BOOL isSynchronous, BOOL isLayerBacked)
 {
-  return flags.synchronous && !flags.layerBacked;
+  return isSynchronous && !isLayerBacked;
 }
 
 _ASPendingState *ASDisplayNodeGetPendingState(ASDisplayNode *node)
@@ -314,7 +314,7 @@ - (instancetype)initWithViewClass:(Class)viewClass
   ASDisplayNodeAssert([viewClass isSubclassOfClass:[UIView class]], @"should initialize with a subclass of UIView");
 
   _viewClass = viewClass;
-  _flags.synchronous = ![viewClass isSubclassOfClass:[_ASDisplayView class]];
+  self.synchronous = ![viewClass isSubclassOfClass:[_ASDisplayView class]];
 
   return self;
 }
@@ -328,7 +328,7 @@ - (instancetype)initWithLayerClass:(Class)layerClass
   ASDisplayNodeAssert([layerClass isSubclassOfClass:[CALayer class]], @"should initialize with a subclass of CALayer");
 
   _layerClass = layerClass;
-  _flags.synchronous = ![layerClass isSubclassOfClass:[_ASDisplayLayer class]];
+  self.synchronous = ![layerClass isSubclassOfClass:[_ASDisplayLayer class]];
   _flags.layerBacked = YES;
 
   return self;
@@ -378,7 +378,7 @@ - (void)setViewBlock:(ASDisplayNodeViewBlock)viewBlock
   ASDisplayNodeAssertNotNil(viewBlock, @"should initialize with a valid block that returns a UIView");
 
   _viewBlock = viewBlock;
-  _flags.synchronous = YES;
+  self.synchronous = YES;
 }
 
 - (void)setLayerBlock:(ASDisplayNodeLayerBlock)layerBlock
@@ -387,7 +387,7 @@ - (void)setLayerBlock:(ASDisplayNodeLayerBlock)layerBlock
   ASDisplayNodeAssertNotNil(layerBlock, @"should initialize with a valid block that returns a CALayer");
 
   _layerBlock = layerBlock;
-  _flags.synchronous = YES;
+  self.synchronous = YES;
   _flags.layerBacked = YES;
 }
 
@@ -411,7 +411,7 @@ - (void)dealloc
   _flags.isDeallocating = YES;
 
   // Synchronous nodes may not be able to call the hierarchy notifications, so only enforce for regular nodes.
-  ASDisplayNodeAssert(_flags.synchronous || !ASInterfaceStateIncludesVisible(_interfaceState), @"Node should always be marked invisible before deallocating. Node: %@", self);
+  ASDisplayNodeAssert(self.isSynchronous || !ASInterfaceStateIncludesVisible(_interfaceState), @"Node should always be marked invisible before deallocating. Node: %@", self);
 
   self.asyncLayer.asyncDelegate = nil;
   _view.asyncdisplaykit_node = nil;
@@ -547,7 +547,7 @@ - (void)__unloadNode
 {
   ASDisplayNodeAssertMainThread();
   ASDisplayNodeAssert([self isNodeLoaded], @"Implementation shouldn't call __unloadNode if not loaded: %@", self);
-  ASDisplayNodeAssert(_flags.synchronous == NO, @"Node created using -initWithViewBlock:/-initWithLayerBlock: cannot be unloaded. Node: %@", self);
+  ASDisplayNodeAssert(self.isSynchronous == NO, @"Node created using -initWithViewBlock:/-initWithLayerBlock: cannot be unloaded. Node: %@", self);
   ASDN::MutexLocker l(__instanceLock__);
 
   if (_flags.layerBacked) {
@@ -583,7 +583,7 @@ - (UIView *)_locked_viewToLoad
   }
 
   // Special handling of wrapping UIKit components
-  if (_flags.synchronous) {
+  if (self.isSynchronous) {
     // UIImageView layers. More details on the flags
     if ([_viewClass isSubclassOfClass:[UIImageView class]]) {
       _flags.canClearContentsOfLayer = NO;
@@ -803,12 +803,6 @@ - (_ASDisplayLayer *)_locked_asyncLayer
   return [_layer isKindOfClass:[_ASDisplayLayer class]] ? (_ASDisplayLayer *)_layer : nil;
 }
 
-- (BOOL)isSynchronous
-{
-  ASDN::MutexLocker l(__instanceLock__);
-  return _flags.synchronous;
-}
-
 - (void)setLayerBacked:(BOOL)isLayerBacked
 {
   // Only call this if assertions are enabled – it could be expensive.
@@ -836,7 +830,7 @@ - (BOOL)isLayerBacked
 - (BOOL)supportsLayerBacking
 {
   ASDN::MutexLocker l(__instanceLock__);
-  return !_flags.synchronous && !_flags.viewEverHadAGestureRecognizerAttached && _viewClass == [_ASDisplayView class] && _layerClass == [_ASDisplayLayer class];
+  return !self.isSynchronous && !_flags.viewEverHadAGestureRecognizerAttached && _viewClass == [_ASDisplayView class] && _layerClass == [_ASDisplayLayer class];
 }
 
 - (BOOL)shouldAnimateSizeChanges
@@ -1948,7 +1942,7 @@ - (BOOL)displaysAsynchronously
  */
 - (BOOL)_locked_displaysAsynchronously
 {
-  return _flags.synchronous == NO && _flags.displaysAsynchronously;
+  return self.isSynchronous == NO && _flags.displaysAsynchronously;
 }
 
 - (void)setDisplaysAsynchronously:(BOOL)displaysAsynchronously
@@ -1958,7 +1952,7 @@ - (void)setDisplaysAsynchronously:(BOOL)displaysAsynchronously
   ASDN::MutexLocker l(__instanceLock__);
 
   // Can't do this for synchronous nodes (using layers that are not _ASDisplayLayer and so we can't control display prevention/cancel)
-  if (_flags.synchronous) {
+  if (self.isSynchronous) {
     return;
   }
 
@@ -2052,7 +2046,7 @@ - (void)setContentsScaleForDisplay:(CGFloat)contentsScaleForDisplay
 - (void)displayImmediately
 {
   ASDisplayNodeAssertMainThread();
-  ASDisplayNodeAssert(!_flags.synchronous, @"this method is designed for asynchronous mode only");
+  ASDisplayNodeAssert(!self.isSynchronous, @"this method is designed for asynchronous mode only");
 
   [self.asyncLayer displayImmediately];
 }
@@ -2073,7 +2067,7 @@ - (void)__setNeedsDisplay
     BOOL nowDisplay = ASInterfaceStateIncludesDisplay(_interfaceState);
     // FIXME: This should not need to recursively display, so create a non-recursive variant.
     // The semantics of setNeedsDisplay (as defined by CALayer behavior) are not recursive.
-    if (_layer != nil && !_flags.synchronous && nowDisplay && [self _implementsDisplay]) {
+    if (_layer != nil && !self.isSynchronous && nowDisplay && [self _implementsDisplay]) {
       shouldScheduleForDisplay = YES;
     }
   }
@@ -2317,7 +2311,7 @@ - (void)setDisplaySuspended:(BOOL)flag
   __instanceLock__.lock();
 
   // Can't do this for synchronous nodes (using layers that are not _ASDisplayLayer and so we can't control display prevention/cancel)
-  if (_flags.synchronous || _flags.displaySuspended == flag) {
+  if (self.isSynchronous || _flags.displaySuspended == flag) {
     __instanceLock__.unlock();
     return;
   }
@@ -3406,7 +3400,7 @@ - (void)setHierarchyState:(ASHierarchyState)newState
 
   // Entered rasterization state.
   if (newState & ASHierarchyStateRasterized) {
-    ASDisplayNodeAssert(_flags.synchronous == NO, @"Node created using -initWithViewBlock:/-initWithLayerBlock: cannot be added to subtree of node with shouldRasterizeDescendants=YES. Node: %@", self);
+    ASDisplayNodeAssert(self.isSynchronous == NO, @"Node created using -initWithViewBlock:/-initWithLayerBlock: cannot be added to subtree of node with shouldRasterizeDescendants=YES. Node: %@", self);
   }
 
   // Entered or exited range managed state.
@@ -3907,7 +3901,7 @@ - (void)_locked_applyPendingViewState
   if (_flags.layerBacked) {
     [_pendingViewState applyToLayer:self.layer];
   } else {
-    BOOL specialPropertiesHandling = ASDisplayNodeNeedsSpecialPropertiesHandlingForFlags(_flags);
+    BOOL specialPropertiesHandling = ASDisplayNodeNeedsSpecialPropertiesHandling(self.isSynchronous, _flags.layerBacked);
     [_pendingViewState applyToView:self.view withSpecialPropertiesHandling:specialPropertiesHandling];
   }
 

Source/Private/ASDisplayNode+UIViewBridge.mm

@@ -241,7 +241,7 @@ - (void)setFrame:(CGRect)rect
 
   // For classes like ASTableNode, ASCollectionNode, ASScrollNode and similar - make sure UIView gets setFrame:
   struct ASDisplayNodeFlags flags = _flags;
-  BOOL specialPropertiesHandling = ASDisplayNodeNeedsSpecialPropertiesHandlingForFlags(flags);
+  BOOL specialPropertiesHandling = ASDisplayNodeNeedsSpecialPropertiesHandling(self.isSynchronous, flags.layerBacked);
 
   BOOL nodeLoaded = __loaded(self);
   BOOL isMainThread = ASDisplayNodeThreadIsMain();
@@ -635,7 +635,7 @@ - (void)setBackgroundColor:(UIColor *)newBackgroundColor
   if (shouldApply) {
     CGColorRef oldBackgroundCGColor = _layer.backgroundColor;
 
-    BOOL specialPropertiesHandling = ASDisplayNodeNeedsSpecialPropertiesHandlingForFlags(_flags);
+    BOOL specialPropertiesHandling = ASDisplayNodeNeedsSpecialPropertiesHandling(self.isSynchronous, _flags.layerBacked);
     if (specialPropertiesHandling) {
         _view.backgroundColor = newBackgroundColor;
     } else {

Source/Private/ASDisplayNodeInternal.h

@@ -38,7 +38,7 @@ NS_ASSUME_NONNULL_BEGIN
 struct ASDisplayNodeFlags;
 
 BOOL ASDisplayNodeSubclassOverridesSelector(Class subclass, SEL selector);
-BOOL ASDisplayNodeNeedsSpecialPropertiesHandlingForFlags(ASDisplayNodeFlags flags);
+BOOL ASDisplayNodeNeedsSpecialPropertiesHandling(BOOL isSynchronous, BOOL isLayerBacked);
 
 /// Get the pending view state for the node, creating one if needed.
 _ASPendingState * ASDisplayNodeGetPendingState(ASDisplayNode * node);
@@ -73,7 +73,6 @@ FOUNDATION_EXPORT NSString * const ASRenderingEngineDidDisplayNodesScheduledBefo
 
   struct ASDisplayNodeFlags {
     // public properties
-    unsigned synchronous:1;
     unsigned viewEverHadAGestureRecognizerAttached:1;
     unsigned layerBacked:1;
     unsigned displaysAsynchronously:1;
@@ -208,6 +207,9 @@ FOUNDATION_EXPORT NSString * const ASRenderingEngineDidDisplayNodesScheduledBefo
 /// Bitmask to check which methods an object overrides.
 @property (nonatomic, assign, readonly) ASDisplayNodeMethodOverrides methodOverrides;
 
+/// Atomic BOOL that indicates whether the node wraps a synchronous layer or view class.
+@property (atomic, assign, readwrite, getter=isSynchronous) BOOL synchronous;
+
 /**
  * Invoked before a call to setNeedsLayout to the underlying view
  */