Fabric: Enabling and disabling EventEmitter at post commit phase

Summary:
@public
We need that to ensure that we will not deliver events to nodes with invalid state.

Reviewed By: mdvacca

Differential Revision: D8886234

fbshipit-source-id: 1d6ca129c97a5dca0411e85909aea48185f46c54

ReactCommon/fabric/uimanager/ShadowTree.cpp

@@ -86,7 +86,7 @@ void ShadowTree::complete(UnsharedRootShadowNode newRootShadowNode) {
     newRootShadowNode
   );
 
-  if (commit(oldRootShadowNode, newRootShadowNode)) {
+  if (commit(oldRootShadowNode, newRootShadowNode, instructions)) {
     emitLayoutEvents(instructions);
 
     if (delegate_) {
@@ -95,7 +95,11 @@ void ShadowTree::complete(UnsharedRootShadowNode newRootShadowNode) {
   }
 }
 
-bool ShadowTree::commit(const SharedRootShadowNode &oldRootShadowNode, const SharedRootShadowNode &newRootShadowNode) {
+bool ShadowTree::commit(
+  const SharedRootShadowNode &oldRootShadowNode,
+  const SharedRootShadowNode &newRootShadowNode,
+  const TreeMutationInstructionList &mutationInstructions
+) {
   std::lock_guard<std::mutex> lock(commitMutex_);
 
   if (oldRootShadowNode != rootShadowNode_) {
@@ -103,6 +107,8 @@ bool ShadowTree::commit(const SharedRootShadowNode &oldRootShadowNode, const Sha
   }
 
   rootShadowNode_ = newRootShadowNode;
+
+  toggleEventEmitters(mutationInstructions);
   return true;
 }
 
@@ -153,6 +159,22 @@ void ShadowTree::emitLayoutEvents(const TreeMutationInstructionList &instruction
   }
 }
 
+void ShadowTree::toggleEventEmitters(const TreeMutationInstructionList &instructions) {
+  std::lock_guard<std::recursive_mutex> lock(EventEmitter::DispatchMutex());
+
+  for (const auto &instruction : instructions) {
+    if (instruction.getType() == TreeMutationInstruction::Deletion) {
+      instruction.getOldChildNode()->getEventEmitter()->setEnabled(false);
+    }
+  }
+
+  for (const auto &instruction : instructions) {
+    if (instruction.getType() == TreeMutationInstruction::Creation) {
+      instruction.getNewChildNode()->getEventEmitter()->setEnabled(true);
+    }
+  }
+}
+
 #pragma mark - Delegate
 
 void ShadowTree::setDelegate(ShadowTreeDelegate *delegate) {

ReactCommon/fabric/uimanager/ShadowTree.h

@@ -77,7 +77,12 @@ private:
 
   UnsharedRootShadowNode cloneRootShadowNode(const LayoutConstraints &layoutConstraints, const LayoutContext &layoutContext) const;
   void complete(UnsharedRootShadowNode newRootShadowNode);
-  bool commit(const SharedRootShadowNode &oldRootShadowNode, const SharedRootShadowNode &newRootShadowNode);
+  bool commit(
+    const SharedRootShadowNode &oldRootShadowNode,
+    const SharedRootShadowNode &newRootShadowNode,
+    const TreeMutationInstructionList &mutationInstructions
+  );
+  void toggleEventEmitters(const TreeMutationInstructionList &instructions);
   void emitLayoutEvents(const TreeMutationInstructionList &instructions);
 
   const Tag rootTag_;