Extract ASLayoutElement and ASLayoutElementStylability into categories #trivial (#131)

* Initial move of code into layout category

* Cleanup

* Some more

Source/ASDisplayNode.h

@@ -121,7 +121,7 @@ extern NSInteger const ASDefaultDrawingPriority;
  *
  */
 
-@interface ASDisplayNode : NSObject <ASLayoutElement, ASLayoutElementStylability>
+@interface ASDisplayNode : NSObject <ASLayoutElementFinalLayoutElement>
 
 /** @name Initializing a node object */
 
@@ -298,23 +298,6 @@ extern NSInteger const ASDefaultDrawingPriority;
 
 /** @name Managing dimensions */
 
-/**
- * @abstract Asks the node to return a layout based on given size range.
- *
- * @param constrainedSize The minimum and maximum sizes the receiver should fit in.
- *
- * @return An ASLayout instance defining the layout of the receiver (and its children, if the box layout model is used).
- *
- * @discussion Though this method does not set the bounds of the view, it does have side effects--caching both the
- * constraint and the result.
- *
- * @warning Subclasses must not override this; it caches results from -calculateLayoutThatFits:.  Calling this method may
- * be expensive if result is not cached.
- *
- * @see [ASDisplayNode(Subclassing) calculateLayoutThatFits:]
- */
-- (ASLayout *)layoutThatFits:(ASSizeRange)constrainedSize;
-
 /**
  * @abstract Provides a way to declare a block to provide an ASLayoutSpec without having to subclass ASDisplayNode and
  * implement layoutSpecThatFits:
@@ -755,6 +738,31 @@ extern NSInteger const ASDefaultDrawingPriority;
 
 @end
 
+@interface ASDisplayNode (ASLayoutElement) <ASLayoutElement>
+
+/**
+ * @abstract Asks the node to return a layout based on given size range.
+ *
+ * @param constrainedSize The minimum and maximum sizes the receiver should fit in.
+ *
+ * @return An ASLayout instance defining the layout of the receiver (and its children, if the box layout model is used).
+ *
+ * @discussion Though this method does not set the bounds of the view, it does have side effects--caching both the
+ * constraint and the result.
+ *
+ * @warning Subclasses must not override this; it caches results from -calculateLayoutThatFits:.  Calling this method may
+ * be expensive if result is not cached.
+ *
+ * @see [ASDisplayNode(Subclassing) calculateLayoutThatFits:]
+ */
+- (ASLayout *)layoutThatFits:(ASSizeRange)constrainedSize;
+
+@end
+
+@interface ASDisplayNode (ASLayoutElementStylability) <ASLayoutElementStylability>
+
+@end
+
 @interface ASDisplayNode (LayoutTransitioning)
 
 /**

Source/ASDisplayNode.mm

@@ -859,40 +859,17 @@ static ASDisplayNodeMethodOverrides GetASDisplayNodeMethodOverrides(Class c)
     + (ASDisplayNodeSubclassOverridesSelector(self.class, @selector(calculateLayoutThatFits:)) ? 1 : 0)) <= 1, \
     @"Subclass %@ must at least provide a layoutSpecBlock or override at most one of the three layout methods: calculateLayoutThatFits:, layoutSpecThatFits:, or calculateSizeThatFits:", NSStringFromClass(self.class))
 
-#pragma mark <ASLayoutElement>
-
-- (ASLayoutElementStyle *)style
-{
-  ASDN::MutexLocker l(__instanceLock__);
-  if (_style == nil) {
-    _style = [[ASLayoutElementStyle alloc] init];
-  }
-  return _style;
-}
-
-- (ASLayoutElementType)layoutElementType
-{
-  return ASLayoutElementTypeDisplayNode;
-}
+#pragma mark <ASLayoutElementTransition>
 
 - (BOOL)canLayoutAsynchronous
 {
   return !self.isNodeLoaded;
 }
 
-- (NSArray<id<ASLayoutElement>> *)sublayoutElements
-{
-  return self.subnodes;
-}
-
-- (instancetype)styledWithBlock:(AS_NOESCAPE void (^)(__kindof ASLayoutElementStyle *style))styleBlock
-{
-  styleBlock(self.style);
-  return self;
-}
-
 ASLayoutElementFinalLayoutElementDefault
 
+#pragma mark <ASDebugNameProvider>
+
 - (NSString *)debugName
 {
   ASDN::MutexLocker l(__instanceLock__);
@@ -907,47 +884,6 @@ ASLayoutElementFinalLayoutElementDefault
   }
 }
 
-#pragma mark Measurement Pass
-
-- (ASLayout *)layoutThatFits:(ASSizeRange)constrainedSize
-{
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wdeprecated-declarations"
-  // For now we just call the deprecated measureWithSizeRange: method to not break old API
-  return [self measureWithSizeRange:constrainedSize];
-#pragma clang diagnostic pop
-}
-
-- (ASLayout *)layoutThatFits:(ASSizeRange)constrainedSize parentSize:(CGSize)parentSize
-{
-  ASDN::MutexLocker l(__instanceLock__);
- 
-  // If one or multiple layout transitions are in flight it still can happen that layout information is requested
-  // on other threads. As the pending and calculated layout to be updated in the layout transition in here just a
-  // layout calculation wil be performed without side effect
-  if ([self _isLayoutTransitionInvalid]) {
-    return [self calculateLayoutThatFits:constrainedSize restrictedToSize:self.style.size relativeToParentSize:parentSize];
-  }
-
-  if (_calculatedDisplayNodeLayout->isValidForConstrainedSizeParentSize(constrainedSize, parentSize)) {
-    ASDisplayNodeAssertNotNil(_calculatedDisplayNodeLayout->layout, @"-[ASDisplayNode layoutThatFits:parentSize:] _calculatedDisplayNodeLayout->layout should not be nil! %@", self);
-    // Our calculated layout is suitable for this constrainedSize, so keep using it and
-    // invalidate any pending layout that has been generated in the past.
-    _pendingDisplayNodeLayout = nullptr;
-    return _calculatedDisplayNodeLayout->layout ?: [ASLayout layoutWithLayoutElement:self size:{0, 0}];
-  }
-  
-  // Create a pending display node layout for the layout pass
-  _pendingDisplayNodeLayout = std::make_shared<ASDisplayNodeLayout>(
-    [self calculateLayoutThatFits:constrainedSize restrictedToSize:self.style.size relativeToParentSize:parentSize],
-    constrainedSize,
-    parentSize
-  );
-  
-  ASDisplayNodeAssertNotNil(_pendingDisplayNodeLayout->layout, @"-[ASDisplayNode layoutThatFits:parentSize:] _pendingDisplayNodeLayout->layout should not be nil! %@", self);
-  return _pendingDisplayNodeLayout->layout ?: [ASLayout layoutWithLayoutElement:self size:{0, 0}];
-}
-
 #pragma mark Layout Pass
 
 - (void)__setNeedsLayout
@@ -1297,7 +1233,6 @@ ASLayoutElementFinalLayoutElementDefault
   _calculatedDisplayNodeLayout = displayNodeLayout;
 }
 
-
 - (CGSize)calculatedSize
 {
   ASDN::MutexLocker l(__instanceLock__);
@@ -4063,46 +3998,13 @@ ASDISPLAYNODE_INLINE BOOL subtreeIsRasterized(ASDisplayNode *node) {
   }
 }
 
-#pragma mark - ASPrimitiveTraitCollection
-
-- (ASPrimitiveTraitCollection)primitiveTraitCollection
-{
-  ASDN::MutexLocker l(__instanceLock__);
-  return _primitiveTraitCollection;
-}
-
-- (void)setPrimitiveTraitCollection:(ASPrimitiveTraitCollection)traitCollection
-{
-  __instanceLock__.lock();
-  if (ASPrimitiveTraitCollectionIsEqualToASPrimitiveTraitCollection(traitCollection, _primitiveTraitCollection) == NO) {
-    _primitiveTraitCollection = traitCollection;
-    ASDisplayNodeLogEvent(self, @"asyncTraitCollectionDidChange: %@", NSStringFromASPrimitiveTraitCollection(traitCollection));
-    __instanceLock__.unlock();
-    
-    [self asyncTraitCollectionDidChange];
-    return;
-  }
-  
-  __instanceLock__.unlock();
-}
-
-- (ASTraitCollection *)asyncTraitCollection
-{
-  ASDN::MutexLocker l(__instanceLock__);
-  return [ASTraitCollection traitCollectionWithASPrimitiveTraitCollection:self.primitiveTraitCollection];
-}
+#pragma mark - Trait Collection Hooks
 
 - (void)asyncTraitCollectionDidChange
 {
   // Subclass override
 }
 
-ASPrimitiveTraitCollectionDeprecatedImplementation
-
-#pragma mark - ASLayoutElementStyleExtensibility
-
-ASLayoutElementStyleExtensibilityForwarding
-
 #if TARGET_OS_TV
 #pragma mark - UIFocusEnvironment Protocol (tvOS)
 
@@ -4136,23 +4038,125 @@ ASLayoutElementStyleExtensibilityForwarding
 }
 #endif
 
-#pragma mark - Deprecated
+@end
 
-// This methods cannot be moved into the category ASDisplayNode (Deprecated). So they need to be declared in ASDisplayNode until removed
+#pragma mark - ASDisplayNode (ASLayoutElement)
+
+@implementation ASDisplayNode (ASLayoutElement)
+
+#pragma mark <ASLayoutElement>
+
+- (ASLayoutElementStyle *)style
+{
+  ASDN::MutexLocker l(__instanceLock__);
+  if (_style == nil) {
+    _style = [[ASLayoutElementStyle alloc] init];
+  }
+  return _style;
+}
+
+- (ASLayoutElementType)layoutElementType
+{
+  return ASLayoutElementTypeDisplayNode;
+}
+
+- (NSArray<id<ASLayoutElement>> *)sublayoutElements
+{
+  return self.subnodes;
+}
+
+#pragma mark Measurement Pass
+
+- (ASLayout *)layoutThatFits:(ASSizeRange)constrainedSize
+{
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+  // For now we just call the deprecated measureWithSizeRange: method to not break old API
+  return [self measureWithSizeRange:constrainedSize];
+#pragma clang diagnostic pop
+}
 
 - (ASLayout *)measureWithSizeRange:(ASSizeRange)constrainedSize
 {
   return [self layoutThatFits:constrainedSize parentSize:constrainedSize.max];
 }
 
-- (BOOL)usesImplicitHierarchyManagement
+- (ASLayout *)layoutThatFits:(ASSizeRange)constrainedSize parentSize:(CGSize)parentSize
 {
-  return self.automaticallyManagesSubnodes;
+  ASDN::MutexLocker l(__instanceLock__);
+ 
+  // If one or multiple layout transitions are in flight it still can happen that layout information is requested
+  // on other threads. As the pending and calculated layout to be updated in the layout transition in here just a
+  // layout calculation wil be performed without side effect
+  if ([self _isLayoutTransitionInvalid]) {
+    return [self calculateLayoutThatFits:constrainedSize restrictedToSize:self.style.size relativeToParentSize:parentSize];
+  }
+
+  if (_calculatedDisplayNodeLayout->isValidForConstrainedSizeParentSize(constrainedSize, parentSize)) {
+    ASDisplayNodeAssertNotNil(_calculatedDisplayNodeLayout->layout, @"-[ASDisplayNode layoutThatFits:parentSize:] _calculatedDisplayNodeLayout->layout should not be nil! %@", self);
+    // Our calculated layout is suitable for this constrainedSize, so keep using it and
+    // invalidate any pending layout that has been generated in the past.
+    _pendingDisplayNodeLayout = nullptr;
+    return _calculatedDisplayNodeLayout->layout ?: [ASLayout layoutWithLayoutElement:self size:{0, 0}];
+  }
+  
+  // Create a pending display node layout for the layout pass
+  _pendingDisplayNodeLayout = std::make_shared<ASDisplayNodeLayout>(
+    [self calculateLayoutThatFits:constrainedSize restrictedToSize:self.style.size relativeToParentSize:parentSize],
+    constrainedSize,
+    parentSize
+  );
+  
+  ASDisplayNodeAssertNotNil(_pendingDisplayNodeLayout->layout, @"-[ASDisplayNode layoutThatFits:parentSize:] _pendingDisplayNodeLayout->layout should not be nil! %@", self);
+  return _pendingDisplayNodeLayout->layout ?: [ASLayout layoutWithLayoutElement:self size:{0, 0}];
 }
 
-- (void)setUsesImplicitHierarchyManagement:(BOOL)enabled
+#pragma mark ASLayoutElementStyleExtensibility
+
+ASLayoutElementStyleExtensibilityForwarding
+
+#pragma mark ASPrimitiveTraitCollection
+
+- (ASPrimitiveTraitCollection)primitiveTraitCollection
 {
-  self.automaticallyManagesSubnodes = enabled;
+  ASDN::MutexLocker l(__instanceLock__);
+  return _primitiveTraitCollection;
+}
+
+- (void)setPrimitiveTraitCollection:(ASPrimitiveTraitCollection)traitCollection
+{
+  __instanceLock__.lock();
+  if (ASPrimitiveTraitCollectionIsEqualToASPrimitiveTraitCollection(traitCollection, _primitiveTraitCollection) == NO) {
+    _primitiveTraitCollection = traitCollection;
+    ASDisplayNodeLogEvent(self, @"asyncTraitCollectionDidChange: %@", NSStringFromASPrimitiveTraitCollection(traitCollection));
+    __instanceLock__.unlock();
+    
+    [self asyncTraitCollectionDidChange];
+    return;
+  }
+  
+  __instanceLock__.unlock();
+}
+
+- (ASTraitCollection *)asyncTraitCollection
+{
+  ASDN::MutexLocker l(__instanceLock__);
+  return [ASTraitCollection traitCollectionWithASPrimitiveTraitCollection:self.primitiveTraitCollection];
+}
+
+ASPrimitiveTraitCollectionDeprecatedImplementation
+
+@end
+
+
+#pragma mark - ASDisplayNode (ASLayoutElementStylability)
+
+@implementation ASDisplayNode (ASLayoutElementStylability)
+
+- (instancetype)styledWithBlock:(AS_NOESCAPE void (^)(__kindof ASLayoutElementStyle *style))styleBlock
+{
+  styleBlock(self.style);
+  return self;
 }
 
 @end
@@ -4298,6 +4302,16 @@ static const char *ASDisplayNodeAssociatedNodeKey = "ASAssociatedNode";
   return isPoints ? CGSizeMake(size.width.value, size.height.value) : CGSizeZero;
 }
 
+- (BOOL)usesImplicitHierarchyManagement
+{
+  return self.automaticallyManagesSubnodes;
+}
+
+- (void)setUsesImplicitHierarchyManagement:(BOOL)enabled
+{
+  self.automaticallyManagesSubnodes = enabled;
+}
+
 - (CGSize)measure:(CGSize)constrainedSize
 {
   return [self layoutThatFits:ASSizeRangeMake(CGSizeZero, constrainedSize)].size;

Source/Details/ASTraitCollection.h

@@ -21,6 +21,7 @@
 
 @class ASTraitCollection;
 @protocol ASLayoutElement;
+@protocol ASTraitEnvironment;
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -63,7 +64,7 @@ extern NSString *NSStringFromASPrimitiveTraitCollection(ASPrimitiveTraitCollecti
  * This function will walk the layout element hierarchy and updates the layout element trait collection for every
  * layout element within the hierarchy.
  */
-extern void ASTraitCollectionPropagateDown(id<ASLayoutElement> root, ASPrimitiveTraitCollection traitCollection);
+extern void ASTraitCollectionPropagateDown(id<ASLayoutElement> element, ASPrimitiveTraitCollection traitCollection);
 
 /// For backward compatibility reasons we redefine the old layout element trait collection struct name
 #define ASEnvironmentTraitCollection ASPrimitiveTraitCollection
@@ -88,7 +89,6 @@ ASDISPLAYNODE_EXTERN_C_END
 - (void)setPrimitiveTraitCollection:(ASPrimitiveTraitCollection)traitCollection;
 
 /**
- * Returns an NSObject-representation of the environment's ASEnvironmentDisplayTraits
  */
 - (ASTraitCollection *)asyncTraitCollection;
 

Source/Details/ASTraitCollection.m

@@ -22,10 +22,14 @@
 
 #pragma mark - ASPrimitiveTraitCollection
 
-extern void ASTraitCollectionPropagateDown(id<ASLayoutElement> root, ASPrimitiveTraitCollection traitCollection) {
-  ASLayoutElementPerformBlockOnEveryElement(root, ^(id<ASLayoutElement>  _Nonnull element) {
+extern void ASTraitCollectionPropagateDown(id<ASLayoutElement> element, ASPrimitiveTraitCollection traitCollection) {
+  if (element) {
     element.primitiveTraitCollection = traitCollection;
-  });
+  }
+  
+  for (id<ASLayoutElement> subelement in element.sublayoutElements) {
+    ASTraitCollectionPropagateDown(subelement, traitCollection);
+  }
 }
 
 ASPrimitiveTraitCollection ASPrimitiveTraitCollectionMakeDefault()

Source/Layout/ASLayoutElement.h

@@ -42,16 +42,6 @@ typedef NS_ENUM(NSUInteger, ASLayoutElementType) {
   ASLayoutElementTypeDisplayNode
 };
 
-ASDISPLAYNODE_EXTERN_C_BEGIN
-
-/**
- This function will walk the layout element hierarchy. It does run the block on the node provided
- directly to the function call.
- */
-extern void ASLayoutElementPerformBlockOnEveryElement(id<ASLayoutElement> root, void(^block)(id<ASLayoutElement> element));
-
-ASDISPLAYNODE_EXTERN_C_END
-
 #pragma mark - ASLayoutElement
 
 /**
@@ -70,7 +60,7 @@ ASDISPLAYNODE_EXTERN_C_END
  * access to the options via convenience properties. If you are creating custom layout spec, then you can
  * extend the backing layout options class to accommodate any new layout options.
  */
-@protocol ASLayoutElement <ASLayoutElementExtensibility, ASLayoutElementFinalLayoutElement, ASTraitEnvironment>
+@protocol ASLayoutElement <ASLayoutElementExtensibility, ASTraitEnvironment>
 
 #pragma mark - Getter
 

Source/Layout/ASLayoutElement.mm

@@ -29,17 +29,6 @@
   #import YOGA_HEADER_PATH
 #endif
 
-extern void ASLayoutElementPerformBlockOnEveryElement(id<ASLayoutElement> element, void(^block)(id<ASLayoutElement> element))
-{
-  if (element) {
-    block(element);
-  }
-
-  for (id<ASLayoutElement> subelement in element.sublayoutElements) {
-    ASLayoutElementPerformBlockOnEveryElement(subelement, block);
-  }
-}
-
 #pragma mark - ASLayoutElementContext
 
 CGFloat const ASLayoutElementParentDimensionUndefined = NAN;

Source/Layout/ASLayoutSpec+Subclasses.mm

@@ -58,7 +58,7 @@
 
 #pragma mark - Final layoutElement
 
-- (id<ASLayoutElement>)layoutElementToAddFromLayoutElement:(id<ASLayoutElement>)child
+- (id<ASLayoutElement>)layoutElementToAddFromLayoutElement:(id<ASLayoutElement, ASLayoutElementFinalLayoutElement>)child
 {
   if (self.isFinalLayoutElement == NO) {
     id<ASLayoutElement> finalLayoutElement = [child finalLayoutElement];

Source/Layout/ASLayoutSpec.h

@@ -24,7 +24,7 @@ NS_ASSUME_NONNULL_BEGIN
 /**
  * A layout spec is an immutable object that describes a layout, loosely inspired by React.
  */
-@interface ASLayoutSpec : NSObject <ASLayoutElement, ASLayoutElementStylability, NSFastEnumeration>
+@interface ASLayoutSpec : NSObject <ASLayoutElement, ASLayoutElementFinalLayoutElement, ASLayoutElementStylability, NSFastEnumeration>
 
 /** 
  * Creation of a layout spec should only happen by a user in layoutSpecThatFits:. During that method, a

Source/Private/ASDisplayNodeInternal.h

@@ -293,17 +293,14 @@ FOUNDATION_EXPORT NSString * const ASRenderingEngineDidDisplayNodesScheduledBefo
  */
 - (nullable ASDisplayNode *)_supernodeWithClass:(Class)supernodeClass checkViewHierarchy:(BOOL)checkViewHierarchy;
 
-/**
- *  Convenience method to access this node's trait collection struct. Externally, users should interact
- *  with the trait collection via ASTraitCollection
- */
-- (ASPrimitiveTraitCollection)primitiveTraitCollection;
-
 /**
  * Whether this node rasterizes its descendants. See -enableSubtreeRasterization.
  */
 @property (atomic, readonly) BOOL rasterizesSubtree;
 
+/**
+ * Called if a gesture recognizer was attached to an _ASDisplayView
+ */
 - (void)nodeViewDidAddGestureRecognizer;
 
 @end

Source/Private/ASLayoutTransition.h

@@ -30,9 +30,9 @@ NS_ASSUME_NONNULL_BEGIN
 #pragma mark - ASLayoutElementTransition
 
 /**
- * Extend the layout element protocol to check if a the element can layout asynchronously.
+ * Objects conform to this project returns if it's possible to layout asynchronous
  */
-@protocol ASLayoutElementTransition <ASLayoutElement>
+@protocol ASLayoutElementTransition <NSObject>
 
 /**
  * @abstract Returns if the layoutElement can be used to layout in an asynchronous way on a background thread.