Fabric: Using ShadowView instead of ShadowNode in Mutations

Summary:
@public
This is quite a big diff but the actual meaningful change is simple: now we use ShadowView class instead of ShadowNode in mutation instructions.
Note:
 * In some places (especially during diffing) we have to operate with ShadowNodeViewPair objects (which represents a pair of ShadowNode and ShadowView). The reason for that is that we cannot construct child ShadowViews from parent ShadowViews because they don't have any information about children.
 * `ShadowTree::emitLayoutEvents` is now much simpler because ShadowView better represents the specifics of this kind of object.
 * The code in RCTMountingManager also became simpler.

This change will allow us to implement more cool tricks soon.

Reviewed By: mdvacca

Differential Revision: D9403564

fbshipit-source-id: dbc7c61af250144d6c7335a01dc30df0005559a2

React/Fabric/Mounting/RCTMountingManager.h

@@ -7,7 +7,8 @@
 
 #import <UIKit/UIKit.h>
 
-#import <fabric/uimanager/TreeMutationInstruction.h>
+#import <fabric/uimanager/ShadowView.h>
+#import <fabric/uimanager/ShadowViewMutation.h>
 #import <React/RCTPrimitives.h>
 #import <React/RCTMountingManagerDelegate.h>
 
@@ -28,8 +29,8 @@ NS_ASSUME_NONNULL_BEGIN
  * The order of mutation tnstructions matters.
  * Can be called from any thread.
  */
-- (void)mutateComponentViewTreeWithMutationInstructions:(facebook::react::TreeMutationInstructionList)instructions
-                                                rootTag:(ReactTag)rootTag;
+- (void)performTransactionWithMutations:(facebook::react::ShadowViewMutationList)mutations
+                                rootTag:(ReactTag)rootTag;
 
 /**
  * Suggests preliminary creation of a component view of given type.

React/Fabric/Mounting/RCTMountingManager.mm

@@ -38,123 +38,112 @@ using namespace facebook::react;
   return self;
 }
 
-- (void)mutateComponentViewTreeWithMutationInstructions:(facebook::react::TreeMutationInstructionList)instructions
-                                                rootTag:(ReactTag)rootTag
+- (void)performTransactionWithMutations:(facebook::react::ShadowViewMutationList)mutations
+                                rootTag:(ReactTag)rootTag
 {
   NSMutableArray<RCTMountItemProtocol> *mountItems =
-    [[NSMutableArray<RCTMountItemProtocol> alloc] initWithCapacity:instructions.size() * 2 /* ~ the worst case */];
+    [[NSMutableArray<RCTMountItemProtocol> alloc] initWithCapacity:mutations.size() * 2 /* ~ the worst case */];
 
-  for (auto instruction : instructions) {
-    switch (instruction.getType()) {
-      case TreeMutationInstruction::Creation: {
-        NSString *componentName = RCTNSStringFromString(instruction.getNewChildNode()->getComponentName(), NSASCIIStringEncoding);
+  for (const auto &mutation : mutations) {
+    switch (mutation.type) {
+      case ShadowViewMutation::Create: {
+        NSString *componentName = RCTNSStringFromString(mutation.newChildShadowView.componentName, NSASCIIStringEncoding);
         RCTCreateMountItem *mountItem =
           [[RCTCreateMountItem alloc] initWithComponentName:componentName
-                                                        tag:instruction.getNewChildNode()->getTag()];
+                                                        tag:mutation.newChildShadowView.tag];
         [mountItems addObject:mountItem];
         break;
       }
 
-      case TreeMutationInstruction::Deletion: {
-        NSString *componentName = RCTNSStringFromString(instruction.getOldChildNode()->getComponentName(), NSASCIIStringEncoding);
+      case ShadowViewMutation::Delete: {
+        NSString *componentName = RCTNSStringFromString(mutation.oldChildShadowView.componentName, NSASCIIStringEncoding);
         RCTDeleteMountItem *mountItem =
           [[RCTDeleteMountItem alloc] initWithComponentName:componentName
-                                                        tag:instruction.getOldChildNode()->getTag()];
+                                                        tag:mutation.oldChildShadowView.tag];
         [mountItems addObject:mountItem];
         break;
       }
 
-      case TreeMutationInstruction::Insertion: {
+      case ShadowViewMutation::Insert: {
         // Props
-        [mountItems addObject:[[RCTUpdatePropsMountItem alloc] initWithTag:instruction.getNewChildNode()->getTag()
+        [mountItems addObject:[[RCTUpdatePropsMountItem alloc] initWithTag:mutation.newChildShadowView.tag
                                                                   oldProps:nullptr
-                                                                  newProps:instruction.getNewChildNode()->getProps()]];
+                                                                  newProps:mutation.newChildShadowView.props]];
 
         // EventEmitter
-        [mountItems addObject:[[RCTUpdateEventEmitterMountItem alloc] initWithTag:instruction.getNewChildNode()->getTag()
-                                                                     eventEmitter:instruction.getNewChildNode()->getEventEmitter()]];
+        [mountItems addObject:[[RCTUpdateEventEmitterMountItem alloc] initWithTag:mutation.newChildShadowView.tag
+                                                                     eventEmitter:mutation.newChildShadowView.eventEmitter]];
 
         // LocalData
-        if (instruction.getNewChildNode()->getLocalData()) {
-          [mountItems addObject:[[RCTUpdateLocalDataMountItem alloc] initWithTag:instruction.getNewChildNode()->getTag()
+        if (mutation.newChildShadowView.localData) {
+          [mountItems addObject:[[RCTUpdateLocalDataMountItem alloc] initWithTag:mutation.newChildShadowView.tag
                                                                     oldLocalData:nullptr
-                                                                    newLocalData:instruction.getNewChildNode()->getLocalData()]];
+                                                                    newLocalData:mutation.newChildShadowView.localData]];
         }
 
         // Layout
-        auto layoutableNewShadowNode =
-          std::dynamic_pointer_cast<const LayoutableShadowNode>(instruction.getNewChildNode());
-
-        if (layoutableNewShadowNode) {
-          [mountItems addObject:[[RCTUpdateLayoutMetricsMountItem alloc] initWithTag:instruction.getNewChildNode()->getTag()
+        if (mutation.newChildShadowView.layoutMetrics != EmptyLayoutMetrics) {
+          [mountItems addObject:[[RCTUpdateLayoutMetricsMountItem alloc] initWithTag:mutation.newChildShadowView.tag
                                                                     oldLayoutMetrics:{}
-                                                                    newLayoutMetrics:layoutableNewShadowNode->getLayoutMetrics()]];
+                                                                    newLayoutMetrics:mutation.newChildShadowView.layoutMetrics]];
         }
 
         // Insertion
         RCTInsertMountItem *mountItem =
-        [[RCTInsertMountItem alloc] initWithChildTag:instruction.getNewChildNode()->getTag()
-                                           parentTag:instruction.getParentNode()->getTag()
-                                               index:instruction.getIndex()];
+          [[RCTInsertMountItem alloc] initWithChildTag:mutation.newChildShadowView.tag
+                                             parentTag:mutation.parentShadowView.tag
+                                                 index:mutation.index];
         [mountItems addObject:mountItem];
 
         break;
       }
 
-      case TreeMutationInstruction::Removal: {
+      case ShadowViewMutation::Remove: {
         RCTRemoveMountItem *mountItem =
-          [[RCTRemoveMountItem alloc] initWithChildTag:instruction.getOldChildNode()->getTag()
-                                             parentTag:instruction.getParentNode()->getTag()
-                                                 index:instruction.getIndex()];
+          [[RCTRemoveMountItem alloc] initWithChildTag:mutation.oldChildShadowView.tag
+                                             parentTag:mutation.parentShadowView.tag
+                                                 index:mutation.index];
         [mountItems addObject:mountItem];
         break;
       }
 
-      case TreeMutationInstruction::Replacement: {
-        SharedShadowNode oldShadowNode = instruction.getOldChildNode();
-        SharedShadowNode newShadowNode = instruction.getNewChildNode();
+      case ShadowViewMutation::Update: {
+        auto oldChildShadowView = mutation.oldChildShadowView;
+        auto newChildShadowView = mutation.newChildShadowView;
 
         // Props
-        if (oldShadowNode->getProps() != newShadowNode->getProps()) {
+        if (oldChildShadowView.props != newChildShadowView.props) {
           RCTUpdatePropsMountItem *mountItem =
-            [[RCTUpdatePropsMountItem alloc] initWithTag:instruction.getOldChildNode()->getTag()
-                                                oldProps:instruction.getOldChildNode()->getProps()
-                                                newProps:instruction.getNewChildNode()->getProps()];
+            [[RCTUpdatePropsMountItem alloc] initWithTag:mutation.oldChildShadowView.tag
+                                                oldProps:mutation.oldChildShadowView.props
+                                                newProps:mutation.newChildShadowView.props];
           [mountItems addObject:mountItem];
         }
 
         // EventEmitter
-        if (oldShadowNode->getEventEmitter() != newShadowNode->getEventEmitter()) {
+        if (oldChildShadowView.eventEmitter != newChildShadowView.eventEmitter) {
           RCTUpdateEventEmitterMountItem *mountItem =
-            [[RCTUpdateEventEmitterMountItem alloc] initWithTag:instruction.getOldChildNode()->getTag()
-                                                   eventEmitter:instruction.getOldChildNode()->getEventEmitter()];
+            [[RCTUpdateEventEmitterMountItem alloc] initWithTag:mutation.oldChildShadowView.tag
+                                                   eventEmitter:mutation.oldChildShadowView.eventEmitter];
           [mountItems addObject:mountItem];
         }
 
         // LocalData
-        if (oldShadowNode->getLocalData() != newShadowNode->getLocalData()) {
+        if (oldChildShadowView.localData != newChildShadowView.localData) {
           RCTUpdateLocalDataMountItem *mountItem =
-            [[RCTUpdateLocalDataMountItem alloc] initWithTag:newShadowNode->getTag()
-                                                oldLocalData:oldShadowNode->getLocalData()
-                                                newLocalData:newShadowNode->getLocalData()];
+            [[RCTUpdateLocalDataMountItem alloc] initWithTag:newChildShadowView.tag
+                                                oldLocalData:oldChildShadowView.localData
+                                                newLocalData:newChildShadowView.localData];
           [mountItems addObject:mountItem];
         }
 
         // Layout
-        auto layoutableOldShadowNode =
-          std::dynamic_pointer_cast<const LayoutableShadowNode>(oldShadowNode);
-
-        if (layoutableOldShadowNode) {
-          auto layoutableNewShadowNode =
-            std::dynamic_pointer_cast<const LayoutableShadowNode>(newShadowNode);
-
-          if (layoutableOldShadowNode->getLayoutMetrics() != layoutableNewShadowNode->getLayoutMetrics()) {
-            RCTUpdateLayoutMetricsMountItem *mountItem =
-              [[RCTUpdateLayoutMetricsMountItem alloc] initWithTag:instruction.getOldChildNode()->getTag()
-                                                  oldLayoutMetrics:layoutableOldShadowNode->getLayoutMetrics()
-                                                  newLayoutMetrics:layoutableNewShadowNode->getLayoutMetrics()];
-            [mountItems addObject:mountItem];
-          }
+        if (oldChildShadowView.layoutMetrics != newChildShadowView.layoutMetrics) {
+          RCTUpdateLayoutMetricsMountItem *mountItem =
+            [[RCTUpdateLayoutMetricsMountItem alloc] initWithTag:mutation.oldChildShadowView.tag
+                                                oldLayoutMetrics:oldChildShadowView.layoutMetrics
+                                                newLayoutMetrics:newChildShadowView.layoutMetrics];
+          [mountItems addObject:mountItem];
         }
 
         break;

React/Fabric/RCTScheduler.h

@@ -12,7 +12,7 @@
 #import <fabric/core/LayoutConstraints.h>
 #import <fabric/core/LayoutContext.h>
 #import <fabric/uimanager/FabricUIManager.h>
-#import <fabric/uimanager/TreeMutationInstruction.h>
+#import <fabric/uimanager/ShadowViewMutation.h>
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -23,7 +23,8 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @protocol RCTSchedulerDelegate
 
-- (void)schedulerDidComputeMutationInstructions:(facebook::react::TreeMutationInstructionList)instructions rootTag:(ReactTag)rootTag;
+- (void)schedulerDidFinishTransaction:(facebook::react::ShadowViewMutationList)mutations
+                              rootTag:(ReactTag)rootTag;
 
 - (void)schedulerDidRequestPreliminaryViewAllocationWithComponentName:(NSString *)componentName;
 

React/Fabric/RCTScheduler.mm

@@ -30,9 +30,9 @@ class SchedulerDelegateProxy: public SchedulerDelegate {
 public:
   SchedulerDelegateProxy(void *scheduler): scheduler_(scheduler) {}
 
-  void schedulerDidComputeMutationInstructions(Tag rootTag, const TreeMutationInstructionList &instructions) override {
+  void schedulerDidFinishTransaction(Tag rootTag, const ShadowViewMutationList &mutations) override {
     RCTScheduler *scheduler = (__bridge RCTScheduler *)scheduler_;
-    [scheduler.delegate schedulerDidComputeMutationInstructions:instructions rootTag:rootTag];
+    [scheduler.delegate schedulerDidFinishTransaction:mutations rootTag:rootTag];
   }
 
   void schedulerDidRequestPreliminaryViewAllocation(ComponentName componentName) override {

React/Fabric/RCTSurfacePresenter.mm

@@ -69,11 +69,11 @@ using namespace facebook::react;
 
 #pragma mark - RCTSchedulerDelegate
 
-- (void)schedulerDidComputeMutationInstructions:(facebook::react::TreeMutationInstructionList)instructions
+- (void)schedulerDidFinishTransaction:(facebook::react::ShadowViewMutationList)mutations
                                         rootTag:(ReactTag)rootTag
 {
-  [_mountingManager mutateComponentViewTreeWithMutationInstructions:instructions
-                                                            rootTag:rootTag];
+  [_mountingManager performTransactionWithMutations:mutations
+                                            rootTag:rootTag];
 }
 
 - (void)schedulerDidRequestPreliminaryViewAllocationWithComponentName:(NSString *)componentName
@@ -89,7 +89,7 @@ using namespace facebook::react;
   [_scheduler registerRootTag:surface.rootTag];
   [self runSurface:surface];
 
-  // FIXME: Mutation instruction MUST produce instruction for root node.
+  // FIXME: mutation MUST produce instruction for root node.
   [_mountingManager.componentViewRegistry dequeueComponentViewWithName:@"Root" tag:surface.rootTag];
 }