Better (right) implementation of `intrinsicContentSize`

Reviewed By: emilsjolander

Differential Revision: D4486767

fbshipit-source-id: d37ea11f9f48425d4d99c29e8bfb6c8ed2353f04

Examples/UIExplorer/UIExplorerUnitTests/RCTShadowViewTests.m

@@ -28,11 +28,10 @@
 {
   [super setUp];
 
-  self.parentView = [self _shadowViewWithConfig:^(YGNodeRef node) {
-    YGNodeStyleSetFlexDirection(node, YGFlexDirectionColumn);
-    YGNodeStyleSetWidth(node, 440);
-    YGNodeStyleSetHeight(node, 440);
-  }];
+  self.parentView = [RCTRootShadowView new];
+  YGNodeStyleSetFlexDirection(self.parentView.cssNode, YGFlexDirectionColumn);
+  YGNodeStyleSetWidth(self.parentView.cssNode, 440);
+  YGNodeStyleSetHeight(self.parentView.cssNode, 440);
   self.parentView.reactTag = @1; // must be valid rootView tag
 }
 
@@ -132,6 +131,7 @@
 - (void)testAssignsSuggestedWidthDimension
 {
   [self _withShadowViewWithStyle:^(YGNodeRef node) {
+                                   YGNodeStyleSetPositionType(node, YGPositionTypeAbsolute);
                                    YGNodeStyleSetPosition(node, YGEdgeLeft, 0);
                                    YGNodeStyleSetPosition(node, YGEdgeTop, 0);
                                    YGNodeStyleSetHeight(node, 10);
@@ -143,6 +143,7 @@
 - (void)testAssignsSuggestedHeightDimension
 {
   [self _withShadowViewWithStyle:^(YGNodeRef node) {
+                                   YGNodeStyleSetPositionType(node, YGPositionTypeAbsolute);
                                    YGNodeStyleSetPosition(node, YGEdgeLeft, 0);
                                    YGNodeStyleSetPosition(node, YGEdgeTop, 0);
                                    YGNodeStyleSetWidth(node, 10);
@@ -154,6 +155,7 @@
 - (void)testDoesNotOverrideDimensionStyleWithSuggestedDimensions
 {
   [self _withShadowViewWithStyle:^(YGNodeRef node) {
+                                   YGNodeStyleSetPositionType(node, YGPositionTypeAbsolute);
                                    YGNodeStyleSetPosition(node, YGEdgeLeft, 0);
                                    YGNodeStyleSetPosition(node, YGEdgeTop, 0);
                                    YGNodeStyleSetWidth(node, 10);
@@ -189,11 +191,12 @@
                 NSStringFromCGRect(actualRect));
 }
 
-- (RCTRootShadowView *)_shadowViewWithConfig:(void(^)(YGNodeRef node))configBlock
+- (RCTShadowView *)_shadowViewWithConfig:(void(^)(YGNodeRef node))configBlock
 {
-  RCTRootShadowView *shadowView = [RCTRootShadowView new];
+  RCTShadowView *shadowView = [RCTShadowView new];
   configBlock(shadowView.cssNode);
   return shadowView;
 }
 
+
 @end

React/Modules/RCTUIManager.m

@@ -473,11 +473,12 @@ dispatch_queue_t RCTGetUIManagerQueue(void)
   NSNumber *reactTag = view.reactTag;
   dispatch_async(RCTGetUIManagerQueue(), ^{
     RCTShadowView *shadowView = self->_shadowViewRegistry[reactTag];
-    RCTAssert(shadowView != nil, @"Could not locate root view with tag #%@", reactTag);
+    RCTAssert(shadowView != nil, @"Could not locate view with tag #%@", reactTag);
 
-    shadowView.intrinsicContentSize = size;
-
-    [self setNeedsLayout];
+    if (!CGSizeEqualToSize(shadowView.intrinsicContentSize, size)) {
+      shadowView.intrinsicContentSize = size;
+      [self setNeedsLayout];
+    }
   });
 }
 

React/Views/RCTShadowView.h

@@ -81,15 +81,16 @@ typedef void (^RCTApplierBlock)(NSDictionary<NSNumber *, UIView *> *viewRegistry
 
 @property (nonatomic, assign) CGRect frame;
 
+/**
+ * Represents the natural size of the view, which is used when explicit size is not set or is ambiguous.
+ * Defaults to `{UIViewNoIntrinsicMetric, UIViewNoIntrinsicMetric}`.
+ */
+@property (nonatomic, assign) CGSize intrinsicContentSize;
+
+
 - (void)setTopLeft:(CGPoint)topLeft;
 - (void)setSize:(CGSize)size;
 
-/**
- * Set the natural size of the view, which is used when no explicit size is set.
- * Use UIViewNoIntrinsicMetric to ignore a dimension.
- */
-- (void)setIntrinsicContentSize:(CGSize)size;
-
 /**
  * Border. Defaults to { 0, 0, 0, 0 }.
  */

React/Views/RCTShadowView.m

@@ -301,6 +301,8 @@ static void RCTProcessMetaPropsBorder(const YGValue metaProps[META_PROP_COUNT],
       _borderMetaProps[ii] = YGValueUndefined;
     }
 
+    _intrinsicContentSize = CGSizeMake(UIViewNoIntrinsicMetric, UIViewNoIntrinsicMetric);
+
     _newView = YES;
     _propagationLifecycle = RCTUpdateLifecycleUninitialized;
     _textLifecycle = RCTUpdateLifecycleUninitialized;
@@ -556,30 +558,59 @@ RCT_POSITION_PROPERTY(Left, left, YGEdgeStart)
   }
 }
 
-static inline void RCTAssignSuggestedDimension(YGNodeRef cssNode, YGDimension dimension, CGFloat amount)
+static inline YGSize RCTShadowViewMeasure(YGNodeRef node, float width, YGMeasureMode widthMode, float height, YGMeasureMode heightMode)
 {
-  if (amount != UIViewNoIntrinsicMetric) {
-    switch (dimension) {
-      case YGDimensionWidth:
-        if (YGNodeStyleGetWidth(cssNode).unit == YGUnitUndefined) {
-          YGNodeStyleSetWidth(cssNode, amount);
-        }
-        break;
-      case YGDimensionHeight:
-        if (YGNodeStyleGetHeight(cssNode).unit == YGUnitUndefined) {
-          YGNodeStyleSetHeight(cssNode, amount);
-        }
-        break;
-    }
+  RCTShadowView *shadowView = (__bridge RCTShadowView *)YGNodeGetContext(node);
+
+  CGSize intrinsicContentSize = shadowView->_intrinsicContentSize;
+  // Replace `UIViewNoIntrinsicMetric` (which equals `-1`) with zero.
+  intrinsicContentSize.width = MAX(0, intrinsicContentSize.width);
+  intrinsicContentSize.height = MAX(0, intrinsicContentSize.height);
+
+  YGSize result;
+
+  switch (widthMode) {
+    case YGMeasureModeUndefined:
+      result.width = intrinsicContentSize.width;
+      break;
+    case YGMeasureModeExactly:
+      result.width = width;
+      break;
+    case YGMeasureModeAtMost:
+      result.width = MIN(width, intrinsicContentSize.width);
+      break;
   }
+
+  switch (heightMode) {
+    case YGMeasureModeUndefined:
+      result.height = intrinsicContentSize.height;
+      break;
+    case YGMeasureModeExactly:
+      result.height = height;
+      break;
+    case YGMeasureModeAtMost:
+      result.height = MIN(height, intrinsicContentSize.height);
+      break;
+  }
+
+  return result;
 }
 
-- (void)setIntrinsicContentSize:(CGSize)size
+- (void)setIntrinsicContentSize:(CGSize)intrinsicContentSize
 {
-  if (YGNodeStyleGetFlexGrow(_cssNode) == 0 && YGNodeStyleGetFlexShrink(_cssNode) == 0) {
-    RCTAssignSuggestedDimension(_cssNode, YGDimensionHeight, size.height);
-    RCTAssignSuggestedDimension(_cssNode, YGDimensionWidth, size.width);
+  if (CGSizeEqualToSize(_intrinsicContentSize, intrinsicContentSize)) {
+    return;
   }
+
+  _intrinsicContentSize = intrinsicContentSize;
+
+  if (CGSizeEqualToSize(_intrinsicContentSize, CGSizeMake(UIViewNoIntrinsicMetric, UIViewNoIntrinsicMetric))) {
+    YGNodeSetMeasureFunc(_cssNode, NULL);
+  } else {
+    YGNodeSetMeasureFunc(_cssNode, RCTShadowViewMeasure);
+  }
+
+  YGNodeMarkDirty(_cssNode);
 }
 
 - (void)setTopLeft:(CGPoint)topLeft