Perform animation transition on measureWithSizeRange instead of separate method

AsyncDisplayKit/ASContextTransitioning.h

@@ -15,6 +15,10 @@
  */
 - (BOOL)isAnimated;
 
+- (ASLayout *)layout;
+
+- (ASSizeRange)constrainedSize;
+
 /**
  @abstract The frame for the given node before the transition began.
  @discussion Returns CGRectNull if the node was not in the hierarchy before the transition.

AsyncDisplayKit/ASDisplayNode+Beta.h

@@ -6,6 +6,8 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
+#import "ASContextTransitioning.h"
+
 @interface ASDisplayNode (Beta)
 
 + (BOOL)usesImplicitHierarchyManagement;
@@ -37,4 +39,32 @@
  */
 @property (nonatomic, strong) ASDisplayNodeContextModifier didDisplayNodeContentWithRenderingContext;
 
+/** @name Layout Transitioning */
+
+/**
+ @discussion A place to perform your animation. New nodes have been inserted here. You can also use this time to re-order the hierarchy.
+ */
+- (void)animateLayoutTransition:(id<ASContextTransitioning>)context;
+
+/**
+ @discussion A place to clean up your nodes after the transition
+ */
+- (void)didCompleteLayoutTransition:(id<ASContextTransitioning>)context;
+
+/**
+ @abstract Invalidates the current layout and begins a relayout of the node to the new layout returned in `calculateLayoutThatFits:`.
+ 
+ @discussion Animation is optional, but will still proceed through the `transitionLayout` methods with `isAnimated == NO`.
+ */
+//- (void)transitionLayoutWithAnimation:(BOOL)animated;
+
+/**
+ @abstract Invalidates the current layout and begins a relayout of the node to the new layout returned in `calculateLayoutThatFits:`.
+ 
+ @discussion Animation is optional, but will still proceed through the `transitionLayout` methods with `isAnimated == NO`.
+ */
+//- (void)transitionLayoutThatFits:(ASSizeRange)constrainedSize animated:(BOOL)animated;
+
+- (ASLayout *)measureWithSizeRange:(ASSizeRange)constrainedSize animated:(BOOL)animated;
+
 @end

AsyncDisplayKit/ASDisplayNode+Subclasses.h

@@ -12,7 +12,6 @@
 #import <AsyncDisplayKit/ASAssert.h>
 #import <AsyncDisplayKit/ASDisplayNode.h>
 #import <AsyncDisplayKit/ASThread.h>
-#import <AsyncDisplayKit/ASContextTransitioning.h>
 
 @class ASLayoutSpec;
 
@@ -156,19 +155,6 @@ NS_ASSUME_NONNULL_BEGIN
 - (void)invalidateCalculatedLayout;
 
 
-/** @name Layout Transitioning */
-
-/**
- @discussion A place to perform your animation. New nodes have been inserted here. You can also use this time to re-order the hierarchy.
- */
-- (void)animateLayoutTransition:(id<ASContextTransitioning>)context;
-
-/**
- @discussion A place to clean up your nodes after the transition
- */
-- (void)didCompleteLayoutTransition:(id<ASContextTransitioning>)context;
-
-
 /** @name Drawing */
 
 

AsyncDisplayKit/ASDisplayNode.h

@@ -571,18 +571,6 @@ NS_ASSUME_NONNULL_BEGIN
 
 @end
 
-@interface ASDisplayNode (Transitioning)
-
-/**
- @abstract Invalidates the current layout and begins a relayout of the node to the new layout returned in `calculateLayoutThatFits:`.
-
- @discussion Animation is optional, but will still proceed through the `transitionLayout` methods with `isAnimated == NO`.
- */
-- (void)transitionLayoutWithAnimation:(BOOL)animated;
-
-@end
-
-
 /**
  * Convenience methods for debugging.
  */

AsyncDisplayKit/ASDisplayNode.mm

@@ -644,6 +644,11 @@ static ASDisplayNodeMethodOverrides GetASDisplayNodeMethodOverrides(Class c)
 }
 
 - (ASLayout *)measureWithSizeRange:(ASSizeRange)constrainedSize
+{
+  return [self measureWithSizeRange:constrainedSize animated:NO];
+}
+
+- (ASLayout *)measureWithSizeRange:(ASSizeRange)constrainedSize animated:(BOOL)animated
 {
   ASDisplayNodeAssertThreadAffinity(self);
   ASDN::MutexLocker l(_propertyLock);
@@ -651,11 +656,13 @@ static ASDisplayNodeMethodOverrides GetASDisplayNodeMethodOverrides(Class c)
   if (![self __shouldSize])
     return nil;
 
+  ASLayout *newLayout;
+  
   // only calculate the size if
   //  - we haven't already
   //  - the constrained size range is different
   if (!_flags.isMeasured || !ASSizeRangeEqualToSizeRange(constrainedSize, _constrainedSize)) {
-    ASLayout *newLayout = [self calculateLayoutThatFits:constrainedSize];
+    newLayout = [self calculateLayoutThatFits:constrainedSize];
 
     if ([[self class] usesImplicitHierarchyManagement]) {
       if (_layout) {
@@ -674,22 +681,37 @@ static ASDisplayNodeMethodOverrides GetASDisplayNodeMethodOverrides(Class c)
         _deletedSubnodes = nil;
       }
       
-      if (!_deferImmediateHierarchyManagement) {
+      if (animated) {
+        [self __transitionToLayout:newLayout constrainedSize:constrainedSize animated:animated];
+      } else {
         [self __implicitlyInsertSubnodes];
         [self __implicitlyRemoveSubnodes];
+        [self __updateLayout:newLayout constrainedSize:constrainedSize];
       }
+    } else {
+      // 1.9.x code path
+      [self __updateLayout:newLayout constrainedSize:constrainedSize];
+    }
+  }
+  return newLayout;
 }
 
-    _layout = newLayout;
+- (void)__updateLayout:(ASLayout *)layout constrainedSize:(ASSizeRange)constrainedSize
+{
+  ASDisplayNodeAssertTrue(layout.layoutableObject == self);
+  ASDisplayNodeAssertTrue(layout.size.width >= 0.0);
+  ASDisplayNodeAssertTrue(layout.size.height >= 0.0);
+
+  _layout = layout;
   _constrainedSize = constrainedSize;
   _flags.isMeasured = YES;
   [self calculatedLayoutDidChange];
+
+  [self __primePlaceholder];
 }
 
-  ASDisplayNodeAssertTrue(_layout.layoutableObject == self);
-  ASDisplayNodeAssertTrue(_layout.size.width >= 0.0);
-  ASDisplayNodeAssertTrue(_layout.size.height >= 0.0);
-
+- (void)__primePlaceholder
+{
   // we generate placeholders at measureWithSizeRange: time so that a node is guaranteed
   // to have a placeholder ready to go. Also, if a node has no size it should not have a placeholder
   if (self.placeholderEnabled && [self _displaysAsynchronously] &&
@@ -702,8 +724,6 @@ static ASDisplayNodeMethodOverrides GetASDisplayNodeMethodOverrides(Class c)
       [self _setupPlaceholderLayerContents];
     }
   }
-
-  return _layout;
 }
 
 /**
@@ -1033,23 +1053,12 @@ static inline CATransform3D _calculateTransformFromReferenceToTarget(ASDisplayNo
 
 #pragma mark - Layout Transition
 
-- (void)transitionLayoutWithAnimation:(BOOL)animated
+- (void)__transitionToLayout:(ASLayout *)layout constrainedSize:(ASSizeRange)constrainedSize animated:(BOOL)animated
 {
-  [self transitionLayoutThatFits:_constrainedSize animated:animated];
-}
-
-- (void)transitionLayoutThatFits:(ASSizeRange)constrainedSize animated:(BOOL)animated
-{
-  [self invalidateCalculatedLayout];
-  _deferImmediateHierarchyManagement = YES;
-  [self measureWithSizeRange:constrainedSize]; // Generate a new layout
-  _deferImmediateHierarchyManagement = NO;
-  [self __transitionLayoutWithAnimation:animated];
-}
-
-- (void)__transitionLayoutWithAnimation:(BOOL)animated
-{
-  _transitionContext = [[_ASTransitionContext alloc] initWithAnimation:animated delegate:self];
+  _transitionContext = [[_ASTransitionContext alloc] initWithLayout:layout
+                                                    constrainedSize:constrainedSize
+                                                           animated:animated
+                                                           delegate:self];
   [self __implicitlyInsertSubnodes];
   [self animateLayoutTransition:_transitionContext];
 }
@@ -1063,6 +1072,7 @@ static inline CATransform3D _calculateTransformFromReferenceToTarget(ASDisplayNo
 - (void)didCompleteTransitionLayout:(id<ASContextTransitioning>)context
 {
   [self __implicitlyRemoveSubnodes];
+  [self __updateLayout:context.layout constrainedSize:context.constrainedSize];
 }
 
 #pragma mark - Implicit node hierarchy managagment

AsyncDisplayKit/_ASTransitionContext.h

@@ -25,6 +25,10 @@
 
 @property (assign, readonly, nonatomic, getter=isAnimated) BOOL animated;
 
-- (instancetype)initWithAnimation:(BOOL)animated delegate:(id<_ASTransitionContextDelegate>)delegate;
+@property (strong, readonly) ASLayout *layout;
+
+@property (assign, readonly) ASSizeRange constrainedSize;
+
+- (instancetype)initWithLayout:(ASLayout *)layout constrainedSize:(ASSizeRange)constrainedSize animated:(BOOL)animated delegate:(id<_ASTransitionContextDelegate>)delegate;
 
 @end

AsyncDisplayKit/_ASTransitionContext.m

@@ -16,10 +16,12 @@
 
 @implementation _ASTransitionContext
 
-- (instancetype)initWithAnimation:(BOOL)animated delegate:(id<_ASTransitionContextDelegate>)delegate
+- (instancetype)initWithLayout:(ASLayout *)layout constrainedSize:(ASSizeRange)constrainedSize animated:(BOOL)animated delegate:(id<_ASTransitionContextDelegate>)delegate
 {
   self = [super init];
   if (self) {
+    _layout = layout;
+    _constrainedSize = constrainedSize;
     _animated = animated;
     _delegate = delegate;
   }