Size flexibility modes for RCTRootView

Reviewed By: javache

Differential Revision: D2526355

fb-gh-sync-id: 095a43bc01f883fdfdad3a086a35682c20c05597

Libraries/ReactIOS/renderApplication.ios.js

@@ -87,11 +87,7 @@ function renderApplication<D, P, S>(
 
 var styles = StyleSheet.create({
   appContainer: {
-    position: 'absolute',
-    left: 0,
-    top: 0,
-    right: 0,
-    bottom: 0,
+    flex: 1,
   },
 });
 

React/Base/RCTRootView.h

@@ -11,6 +11,20 @@
 
 #import "RCTBridge.h"
 
+/**
+ * This enum is used to define size flexibility type of the root view.
+ * If a dimension is flexible, the view will recalculate that dimension
+ * so the content fits. Recalculations are performed when the root's frame,
+ * size flexibility mode or content size changes. After a recalculation,
+ * TODO:<DelegateName> will be called with the new size passed as an argument.
+ */
+typedef NS_ENUM(NSInteger, RCTRootViewSizeFlexibility) {
+  RCTRootViewSizeFlexibilityNone = 0,
+  RCTRootViewSizeFlexibilityWidth,
+  RCTRootViewSizeFlexibilityHeight,
+  RCTRootViewSizeFlexibilityWidthAndHeight,
+};
+
 /**
  * This notification is sent when the first subviews are added to the root view
  * after the application has loaded. This is used to hide the `loadingView`, and
@@ -71,6 +85,11 @@ extern NSString *const RCTContentDidAppearNotification;
  */
 @property (nonatomic, strong) Class executorClass;
 
+/**
+ * The size flexibility mode of the root view.
+ */
+@property (nonatomic, assign) RCTRootViewSizeFlexibility sizeFlexibility;
+
 /**
  * The backing view controller of the root view.
  */

React/Base/RCTRootView.m

@@ -72,6 +72,7 @@ NSString *const RCTContentDidAppearNotification = @"RCTContentDidAppearNotificat
     _initialProperties = [initialProperties copy];
     _loadingViewFadeDelay = 0.25;
     _loadingViewFadeDuration = 0.25;
+    _sizeFlexibility = RCTRootViewSizeFlexibilityNone;
 
     [[NSNotificationCenter defaultCenter] addObserver:self
                                              selector:@selector(javaScriptDidLoad:)
@@ -189,6 +190,12 @@ RCT_NOT_IMPLEMENTED(- (instancetype)initWithCoder:(NSCoder *)aDecoder)
                    args:@[moduleName, appParameters]];
 }
 
+- (void)setSizeFlexibility:(RCTRootViewSizeFlexibility)sizeFlexibility
+{
+  _sizeFlexibility = sizeFlexibility;
+  [self setNeedsLayout];
+}
+
 - (void)layoutSubviews
 {
   [super layoutSubviews];

React/Modules/RCTUIManager.m

@@ -347,11 +347,26 @@ extern NSString *RCTBridgeModuleNameForClass(Class cls);
 {
   RCTAssertMainThread();
 
+  // The following variables have no meaning if the view is not a react root view
+  RCTRootView *rootView = (RCTRootView *)[view superview];
+  RCTRootViewSizeFlexibility sizeFlexibility = rootView != nil ? rootView.sizeFlexibility : RCTRootViewSizeFlexibilityNone;
+
   NSNumber *reactTag = view.reactTag;
   dispatch_async(_shadowQueue, ^{
     RCTShadowView *rootShadowView = _shadowViewRegistry[reactTag];
     RCTAssert(rootShadowView != nil, @"Could not locate root view with tag #%@", reactTag);
-    rootShadowView.frame = frame;
+
+    if (RCTIsReactRootView(reactTag)) {
+      if (CGRectEqualToRect(frame, rootShadowView.frame) && rootShadowView.sizeFlexibility == sizeFlexibility) {
+        // This is to prevent infinite recursion when the frame update is trigerred by TODO(8608567):<DelegateName>
+        return;
+      }
+      rootShadowView.frame = frame;
+      rootShadowView.sizeFlexibility = sizeFlexibility;
+    } else {
+      rootShadowView.frame = frame;
+    }
+
     [rootShadowView updateLayout];
 
     [self batchDidComplete];
@@ -437,8 +452,7 @@ extern NSString *RCTBridgeModuleNameForClass(Class cls);
   // these structures in the UI-thread block. `NSMutableArray` is not thread
   // safe so we rely on the fact that we never mutate it after it's passed to
   // the main thread.
-  [rootShadowView collectRootUpdatedFrames:viewsWithNewFrames
-                          parentConstraint:(CGSize){CSS_UNDEFINED, CSS_UNDEFINED}];
+  [rootShadowView collectRootUpdatedFrames:viewsWithNewFrames];
 
   // Parallel arrays are built and then handed off to main thread
   NSMutableArray *frameReactTags = [NSMutableArray arrayWithCapacity:viewsWithNewFrames.count];

React/Views/RCTShadowView.h

@@ -11,6 +11,7 @@
 
 #import "Layout.h"
 #import "RCTComponent.h"
+#import "RCTRootView.h"
 
 @class RCTSparseArray;
 
@@ -64,6 +65,12 @@ typedef void (^RCTApplierBlock)(RCTSparseArray *viewRegistry);
 - (void)setTopLeft:(CGPoint)topLeft;
 - (void)setSize:(CGSize)size;
 
+/**
+ * Size flexibility type used to find size constraints.
+ * Default to RCTRootViewSizeFlexibilityNone
+ */
+@property (nonatomic, assign) RCTRootViewSizeFlexibility sizeFlexibility;
+
 /**
  * Border. Defaults to { 0, 0, 0, 0 }.
  */
@@ -127,8 +134,7 @@ typedef void (^RCTApplierBlock)(RCTSparseArray *viewRegistry);
  * Calculate all views whose frame needs updating after layout has been calculated.
  * The viewsWithNewFrame set contains the reactTags of the views that need updating.
  */
-- (void)collectRootUpdatedFrames:(NSMutableSet *)viewsWithNewFrame
-                parentConstraint:(CGSize)parentConstraint;
+- (void)collectRootUpdatedFrames:(NSMutableSet *)viewsWithNewFrame;
 
 /**
  * Recursively apply layout to children.

React/Views/RCTShadowView.m

@@ -215,9 +215,32 @@ static void RCTProcessMetaProps(const float metaProps[META_PROP_COUNT], float st
   }
 }
 
-- (void)collectRootUpdatedFrames:(NSMutableSet *)viewsWithNewFrame
-                parentConstraint:(__unused CGSize)parentConstraint
+
+- (void)applySizeConstraints
 {
+  switch (_sizeFlexibility) {
+    case RCTRootViewSizeFlexibilityNone:
+      break;
+    case RCTRootViewSizeFlexibilityWidth:
+      _cssNode->style.dimensions[CSS_WIDTH] = CSS_UNDEFINED;
+      break;
+    case RCTRootViewSizeFlexibilityHeight:
+      _cssNode->style.dimensions[CSS_HEIGHT] = CSS_UNDEFINED;
+      break;
+    case RCTRootViewSizeFlexibilityWidthAndHeight:
+      _cssNode->style.dimensions[CSS_WIDTH] = CSS_UNDEFINED;
+      _cssNode->style.dimensions[CSS_HEIGHT] = CSS_UNDEFINED;
+      break;
+  }
+}
+
+- (void)collectRootUpdatedFrames:(NSMutableSet *)viewsWithNewFrame
+{
+  RCTAssert(RCTIsReactRootView(self.reactTag),
+            @"The method has been called on a view with react tag %@, which is not a root view", self.reactTag);
+
+  [self applySizeConstraints];
+
   [self fillCSSNode:_cssNode];
   layoutNode(_cssNode, CSS_UNDEFINED, CSS_DIRECTION_INHERIT);
   [self applyLayoutNode:_cssNode viewsWithNewFrame:viewsWithNewFrame absolutePosition:CGPointZero];
@@ -245,6 +268,7 @@ static void RCTProcessMetaProps(const float metaProps[META_PROP_COUNT], float st
   if ((self = [super init])) {
 
     _frame = CGRectMake(0, 0, CSS_UNDEFINED, CSS_UNDEFINED);
+    _sizeFlexibility = RCTRootViewSizeFlexibilityNone;
 
     for (unsigned int ii = 0; ii < META_PROP_COUNT; ii++) {
       _paddingMetaProps[ii] = CSS_UNDEFINED;