More iOS animation fixes

Summary:
Main change is to the property diffing - we now use the last known props set on the view rather than the default props to compute the diff. This requires exposing a `getProps` method on all view components which should be fine I think.

I also realized that in more complex animations with multiple nodes, the node that the animation starts on might not be connected to a view, so we don't know if it's fabric just based on that, so we have to do a recursive search through the children to find if there are any that are associated with a fabric view to decide we should start the animation immediately. Unfortunately there can still be a timing gap here since the animated API is async and the uimanager API is sync - I'll need to change the animated API to be sync to completely fix this.

Reviewed By: shergin

Differential Revision: D14732028

fbshipit-source-id: 882c056b0b63aa576f8e42439be405cf7fb3147a

Libraries/NativeAnimation/Nodes/RCTAnimatedNode.h

@@ -23,6 +23,8 @@
 
 @property (nonatomic, readonly) BOOL needsUpdate;
 
+-(BOOL)isManagedByFabric;
+
 /**
  * Marks a node and its children as needing update.
  */

Libraries/NativeAnimation/Nodes/RCTAnimatedNode.m

@@ -115,4 +115,14 @@ RCT_NOT_IMPLEMENTED(- (instancetype)init)
   // during the current update loop
 }
 
+- (BOOL)isManagedByFabric
+{
+  for (RCTAnimatedNode *child in _childNodes.objectEnumerator) {
+    if ([child isManagedByFabric]) {
+      return YES;
+    }
+  }
+  return NO;
+}
+
 @end

Libraries/NativeAnimation/Nodes/RCTPropsAnimatedNode.m

@@ -36,6 +36,11 @@
   return self;
 }
 
+- (BOOL)isManagedByFabric
+{
+  return _managedByFabric;
+}
+
 - (void)connectToView:(NSNumber *)viewTag
              viewName:(NSString *)viewName
                bridge:(RCTBridge *)bridge

Libraries/NativeAnimation/RCTNativeAnimatedModule.m

@@ -19,7 +19,6 @@ typedef void (^AnimatedOperation)(RCTNativeAnimatedNodesManager *nodesManager);
   // Operations called before views have been updated.
   NSMutableArray<AnimatedOperation> *_preOperations;
   NSMutableDictionary<NSNumber *, NSNumber *> *_animIdIsManagedByFabric;
-  NSMutableDictionary<NSNumber *, NSNumber *> *_animatedNodeIsManagedByFabric;
 }
 
 RCT_EXPORT_MODULE();
@@ -88,7 +87,7 @@ RCT_EXPORT_METHOD(startAnimatingNode:(nonnull NSNumber *)animationId
   [self addOperationBlock:^(RCTNativeAnimatedNodesManager *nodesManager) {
     [nodesManager startAnimatingNode:animationId nodeTag:nodeTag config:config endCallback:callBack];
   }];
-  if ([_animatedNodeIsManagedByFabric[nodeTag] boolValue]) {
+  if ([_nodesManager isNodeManagedByFabric:nodeTag]) {
     _animIdIsManagedByFabric[animationId] = @YES;
     [self flushOperationQueues];
   }
@@ -138,9 +137,6 @@ RCT_EXPORT_METHOD(connectAnimatedNodeToView:(nonnull NSNumber *)nodeTag
                   viewTag:(nonnull NSNumber *)viewTag)
 {
   NSString *viewName = [self.bridge.uiManager viewNameForReactTag:viewTag];
-  if (RCTUIManagerTypeForTagIsFabric(nodeTag)) {
-    _animatedNodeIsManagedByFabric[nodeTag] = @YES;
-  }
   [self addOperationBlock:^(RCTNativeAnimatedNodesManager *nodesManager) {
     [nodesManager connectAnimatedNodeToView:nodeTag viewTag:viewTag viewName:viewName];
   }];

Libraries/NativeAnimation/RCTNativeAnimatedNodesManager.h

@@ -19,6 +19,8 @@
 
 - (void)stepAnimations:(nonnull CADisplayLink *)displaylink;
 
+- (BOOL)isNodeManagedByFabric:(nonnull NSNumber *)tag;
+
 // graph
 
 - (void)createAnimatedNode:(nonnull NSNumber *)tag

Libraries/NativeAnimation/RCTNativeAnimatedNodesManager.m

@@ -50,6 +50,12 @@
   return self;
 }
 
+- (BOOL)isNodeManagedByFabric:(nonnull NSNumber *)tag
+{
+  RCTAnimatedNode *node = _animationNodes[tag];
+  return [node isManagedByFabric];
+}
+
 #pragma mark -- Graph
 
 - (void)createAnimatedNode:(nonnull NSNumber *)tag

React/Fabric/Mounting/ComponentViews/View/RCTViewComponentView.mm

@@ -29,10 +29,14 @@ using namespace facebook::react;
     static const auto defaultProps = std::make_shared<const ViewProps>();
     _props = defaultProps;
   }
-
   return self;
 }
 
+- (facebook::react::SharedProps)props
+{
+  return _props;
+}
+
 - (void)setContentView:(UIView *)contentView
 {
   if (_contentView) {

React/Fabric/Mounting/RCTComponentViewProtocol.h

@@ -85,6 +85,11 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)prepareForRecycle;
 
+/**
+ * Read the last props used to update the view.
+ */
+- (facebook::react::SharedProps)props;
+
 @end
 
 NS_ASSUME_NONNULL_END

React/Fabric/Mounting/RCTMountingManager.h

@@ -9,6 +9,7 @@
 
 #import <React/RCTMountingManagerDelegate.h>
 #import <React/RCTPrimitives.h>
+#import <react/core/ComponentDescriptor.h>
 #import <react/core/ReactPrimitives.h>
 #import <react/mounting/ShadowView.h>
 #import <react/mounting/ShadowViewMutation.h>
@@ -40,8 +41,9 @@ NS_ASSUME_NONNULL_BEGIN
 - (void)optimisticallyCreateComponentViewWithComponentHandle:(facebook::react::ComponentHandle)componentHandle;
 
 - (void)synchronouslyUpdateViewOnUIThread:(ReactTag)reactTag
-                                 oldProps:(facebook::react::SharedProps)oldProps
-                                 newProps:(facebook::react::SharedProps)newProps;
+                             changedProps:(NSDictionary *)props
+                      componentDescriptor:(const facebook::react::ComponentDescriptor &)componentDescriptor;
+
 @end
 
 NS_ASSUME_NONNULL_END

React/Fabric/Mounting/RCTMountingManager.mm

@@ -8,8 +8,10 @@
 #import "RCTMountingManager.h"
 
 #import <React/RCTAssert.h>
+#import <React/RCTFollyConvert.h>
 #import <React/RCTUtils.h>
 #import <react/core/LayoutableShadowNode.h>
+#import <react/core/RawProps.h>
 #import <react/debug/SystraceSection.h>
 
 #import "RCTComponentViewProtocol.h"
@@ -40,7 +42,7 @@ using namespace facebook::react;
   return self;
 }
 
-- (void)performTransactionWithMutations:(facebook::react::ShadowViewMutationList)mutations rootTag:(ReactTag)rootTag
+- (void)performTransactionWithMutations:(ShadowViewMutationList)mutations rootTag:(ReactTag)rootTag
 {
   NSMutableArray<RCTMountItemProtocol> *mountItems;
 
@@ -193,9 +195,12 @@ using namespace facebook::react;
 }
 
 - (void)synchronouslyUpdateViewOnUIThread:(ReactTag)reactTag
-                                 oldProps:(SharedProps)oldProps
-                                 newProps:(SharedProps)newProps
+                             changedProps:(NSDictionary *)props
+                      componentDescriptor:(const ComponentDescriptor &)componentDescriptor
 {
+  UIView<RCTComponentViewProtocol> *componentView = [self->_componentViewRegistry componentViewByTag:reactTag];
+  SharedProps oldProps = [componentView props];
+  SharedProps newProps = componentDescriptor.cloneProps(oldProps, RawProps(convertIdToFollyDynamic(props)));
   RCTUpdatePropsMountItem *mountItem = [[RCTUpdatePropsMountItem alloc] initWithTag:reactTag
                                                                            oldProps:oldProps
                                                                            newProps:newProps];

React/Fabric/Mounting/UIView+ComponentViewProtocol.h

@@ -34,6 +34,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)prepareForRecycle;
 
+- (facebook::react::SharedProps)props;
+
 @end
 
 NS_ASSUME_NONNULL_END

React/Fabric/Mounting/UIView+ComponentViewProtocol.mm

@@ -87,4 +87,10 @@ using namespace facebook::react;
   // Default implementation does nothing.
 }
 
+- (facebook::react::SharedProps)props
+{
+  RCTAssert(NO, @"props access should be implemented by RCTViewComponentView.");
+  return nullptr;
+}
+
 @end

React/Fabric/RCTSurfacePresenter.mm

@@ -74,7 +74,7 @@ using namespace facebook::react;
     } else {
       _reactNativeConfig = std::make_shared<const EmptyReactNativeConfig>();
     }
-    
+
     _observers = [NSMutableArray array];
 
     [[NSNotificationCenter defaultCenter] addObserver:self
@@ -176,17 +176,9 @@ using namespace facebook::react;
   }
   ComponentHandle handle = [[componentView class] componentHandle];
   const facebook::react::ComponentDescriptor &componentDescriptor = [self._scheduler getComponentDescriptor:handle];
-
-  // Note: we use an empty object for `oldProps` to rely on the diffing algorithm internal to the
-  // RCTComponentViewProtocol::updateProps method. If there is a bug in that diffing, some props
-  // could get reset. One way around this would be to require all RCTComponentViewProtocol
-  // implementations to expose their current props so we could clone them, but that could be
-  // problematic for threading and other reasons.
-  facebook::react::SharedProps newProps =
-      componentDescriptor.cloneProps(nullptr, RawProps(convertIdToFollyDynamic(props)));
-  facebook::react::SharedProps oldProps = componentDescriptor.cloneProps(nullptr, RawProps(folly::dynamic::object()));
-
-  [self->_mountingManager synchronouslyUpdateViewOnUIThread:tag oldProps:oldProps newProps:newProps];
+  [self->_mountingManager synchronouslyUpdateViewOnUIThread:tag
+                                               changedProps:props
+                                        componentDescriptor:componentDescriptor];
   return YES;
 }
 
@@ -225,7 +217,7 @@ using namespace facebook::react;
     // Make sure initializeBridge completed
     messageQueueThread->runOnQueueSync([] {});
   }
-  
+
   auto runtime = (facebook::jsi::Runtime *)((RCTCxxBridge *)_batchedBridge).runtime;
 
   RuntimeExecutor runtimeExecutor =