Expose instance handles from shadow nodes directly, instead of from event emitters/targets (#37553)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/37553

## Context

I added some getters in EventTarget/EventEmitter to access the React instance handle for a given shadow node/shadow node family in https://github.com/facebook/react-native/commit/43864a1d6025bfc4483dded115d51f7613018199 (D44022477), so I could implement DOM traversal methods easily.

I wanted to reuse that method to implement `MutationObserver` and `IntersectionObserver`, but unfortunately `EventEmitter`/`EventTarget` only allow access to the instance handle as long as the shadow node is mounted. That makes sense for events, but not for this use case, as with `MutationObserver` we intentionally want to have access to unmounted nodes when creating the list of `addedNodes` and `removedNodes` for the `MutationRecord` (depending on when exactly we generate this list, either `addedNodes` or `removedNodes` wouldn't be mounted).

## Changes

This reverts my original change and adds a new field in `ShadowNodeFamily` to provide access to the `InstanceHandle` at any point (even if the node isn't mounted).

This provides the same guarantees as the original method, keeping weak references to the handles to avoid memory leaks.

Changelog: [internal]

Reviewed By: sammy-SC

Differential Revision: D46149084

fbshipit-source-id: f76abae50134a5d55a98cab42eebeb62084024f9

packages/react-native/ReactCommon/react/renderer/animations/tests/LayoutAnimationTest.cpp

@@ -56,8 +56,6 @@ static void testShadowNodeTreeLifeCycleLayoutAnimations(
       ViewComponentDescriptor(componentDescriptorParameters);
   auto rootComponentDescriptor =
       RootComponentDescriptor(componentDescriptorParameters);
-  auto noopEventEmitter =
-      std::make_shared<ViewEventEmitter const>(nullptr, -1, eventDispatcher);
 
   PropsParserContext parserContext{-1, *contextContainer};
 
@@ -95,7 +93,7 @@ static void testShadowNodeTreeLifeCycleLayoutAnimations(
     auto surfaceId = SurfaceId(surfaceIdInt);
 
     auto family = rootComponentDescriptor.createFamily(
-        {Tag(surfaceIdInt), surfaceId, nullptr}, nullptr);
+        {Tag(surfaceIdInt), surfaceId, nullptr});
 
     // Creating an initial root shadow node.
     auto emptyRootNode = std::const_pointer_cast<RootShadowNode>(

packages/react-native/ReactCommon/react/renderer/componentregistry/ComponentDescriptorRegistry.cpp

@@ -126,12 +126,13 @@ ShadowNode::Shared ComponentDescriptorRegistry::createNode(
     std::string const &viewName,
     SurfaceId surfaceId,
     folly::dynamic const &propsDynamic,
-    SharedEventTarget const &eventTarget) const {
+    InstanceHandle::Shared const &instanceHandle) const {
   auto unifiedComponentName = componentNameByReactViewName(viewName);
   auto const &componentDescriptor = this->at(unifiedComponentName);
 
-  auto const fragment = ShadowNodeFamilyFragment{tag, surfaceId, nullptr};
-  auto family = componentDescriptor.createFamily(fragment, eventTarget);
+  auto const fragment =
+      ShadowNodeFamilyFragment{tag, surfaceId, instanceHandle};
+  auto family = componentDescriptor.createFamily(fragment);
   auto const props = componentDescriptor.cloneProps(
       PropsParserContext{surfaceId, *contextContainer_.get()},
       nullptr,

packages/react-native/ReactCommon/react/renderer/componentregistry/ComponentDescriptorRegistry.h

@@ -14,6 +14,7 @@
 
 #include <react/renderer/componentregistry/ComponentDescriptorProvider.h>
 #include <react/renderer/core/ComponentDescriptor.h>
+#include <react/renderer/core/InstanceHandle.h>
 #include <react/utils/ContextContainer.h>
 
 namespace facebook::react {
@@ -59,7 +60,7 @@ class ComponentDescriptorRegistry {
       std::string const &viewName,
       SurfaceId surfaceId,
       folly::dynamic const &props,
-      SharedEventTarget const &eventTarget) const;
+      InstanceHandle::Shared const &instanceHandle) const;
 
   void setFallbackComponentDescriptor(
       const SharedComponentDescriptor &descriptor);

packages/react-native/ReactCommon/react/renderer/core/ComponentDescriptor.h

@@ -8,6 +8,8 @@
 #pragma once
 
 #include <react/renderer/core/EventDispatcher.h>
+#include <react/renderer/core/EventEmitter.h>
+#include <react/renderer/core/InstanceHandle.h>
 #include <react/renderer/core/Props.h>
 #include <react/renderer/core/PropsParserContext.h>
 #include <react/renderer/core/RawPropsParser.h>
@@ -136,8 +138,13 @@ class ComponentDescriptor {
    * Creates a shadow node family for particular node.
    */
   virtual ShadowNodeFamily::Shared createFamily(
-      ShadowNodeFamilyFragment const &fragment,
-      SharedEventTarget eventTarget) const = 0;
+      ShadowNodeFamilyFragment const &fragment) const = 0;
+
+  /*
+   * Creates an event emitter for particular node.
+   */
+  virtual SharedEventEmitter createEventEmitter(
+      InstanceHandle::Shared const &instanceHandle) const = 0;
 
  protected:
   EventDispatcher::Weak eventDispatcher_;

packages/react-native/ReactCommon/react/renderer/core/ConcreteComponentDescriptor.h

@@ -180,17 +180,20 @@ class ConcreteComponentDescriptor : public ComponentDescriptor {
   }
 
   ShadowNodeFamily::Shared createFamily(
-      ShadowNodeFamilyFragment const &fragment,
-      SharedEventTarget eventTarget) const override {
-    auto eventEmitter = std::make_shared<ConcreteEventEmitter const>(
-        std::move(eventTarget), fragment.tag, eventDispatcher_);
+      ShadowNodeFamilyFragment const &fragment) const override {
     return std::make_shared<ShadowNodeFamily>(
         ShadowNodeFamilyFragment{
-            fragment.tag, fragment.surfaceId, eventEmitter},
+            fragment.tag, fragment.surfaceId, fragment.instanceHandle},
         eventDispatcher_,
         *this);
   }
 
+  SharedEventEmitter createEventEmitter(
+      InstanceHandle::Shared const &instanceHandle) const override {
+    return std::make_shared<ConcreteEventEmitter const>(
+        std::make_shared<EventTarget>(instanceHandle), eventDispatcher_);
+  }
+
  protected:
   /*
    * Called immediately after `ShadowNode` is created or cloned.

packages/react-native/ReactCommon/react/renderer/core/EventEmitter.cpp

@@ -43,7 +43,6 @@ ValueFactory EventEmitter::defaultPayloadFactory() {
 
 EventEmitter::EventEmitter(
     SharedEventTarget eventTarget,
-    Tag /*tag*/,
     EventDispatcher::Weak eventDispatcher)
     : eventTarget_(std::move(eventTarget)),
       eventDispatcher_(std::move(eventDispatcher)) {}
@@ -131,8 +130,4 @@ void EventEmitter::setEnabled(bool enabled) const {
   }
 }
 
-const SharedEventTarget &EventEmitter::getEventTarget() const {
-  return eventTarget_;
-}
-
 } // namespace facebook::react

packages/react-native/ReactCommon/react/renderer/core/EventEmitter.h

@@ -38,7 +38,6 @@ class EventEmitter {
 
   EventEmitter(
       SharedEventTarget eventTarget,
-      Tag tag,
       EventDispatcher::Weak eventDispatcher);
 
   virtual ~EventEmitter() = default;
@@ -55,8 +54,6 @@ class EventEmitter {
    */
   void setEnabled(bool enabled) const;
 
-  SharedEventTarget const &getEventTarget() const;
-
  protected:
 #ifdef ANDROID
   // We need this temporarily due to lack of Java-counterparts for particular

packages/react-native/ReactCommon/react/renderer/core/EventTarget.cpp

@@ -13,14 +13,9 @@ namespace facebook::react {
 
 using Tag = EventTarget::Tag;
 
-EventTarget::EventTarget(
-    jsi::Runtime &runtime,
-    jsi::Value const &instanceHandle,
-    Tag tag)
-    : weakInstanceHandle_(
-          jsi::WeakObject(runtime, instanceHandle.asObject(runtime))),
-      strongInstanceHandle_(jsi::Value::null()),
-      tag_(tag) {}
+EventTarget::EventTarget(InstanceHandle::Shared instanceHandle)
+    : instanceHandle_(std::move(instanceHandle)),
+      strongInstanceHandle_(jsi::Value::null()) {}
 
 void EventTarget::setEnabled(bool enabled) const {
   enabled_ = enabled;
@@ -31,7 +26,7 @@ void EventTarget::retain(jsi::Runtime &runtime) const {
     return;
   }
 
-  strongInstanceHandle_ = weakInstanceHandle_.lock(runtime);
+  strongInstanceHandle_ = instanceHandle_->getInstanceHandle(runtime);
 
   // Having a `null` or `undefined` object here indicates that
   // `weakInstanceHandle_` was already deallocated. This should *not* happen by
@@ -62,7 +57,7 @@ jsi::Value EventTarget::getInstanceHandle(jsi::Runtime &runtime) const {
 }
 
 Tag EventTarget::getTag() const {
-  return tag_;
+  return instanceHandle_->getTag();
 }
 
 } // namespace facebook::react

packages/react-native/ReactCommon/react/renderer/core/EventTarget.h

@@ -7,9 +7,9 @@
 
 #pragma once
 
-#include <memory>
-
 #include <jsi/jsi.h>
+#include <react/renderer/core/InstanceHandle.h>
+#include <memory>
 
 namespace facebook::react {
 
@@ -34,7 +34,7 @@ class EventTarget {
   /*
    * Constructs an EventTarget from a weak instance handler and a tag.
    */
-  EventTarget(jsi::Runtime &runtime, jsi::Value const &instanceHandle, Tag tag);
+  explicit EventTarget(InstanceHandle::Shared instanceHandle);
 
   /*
    * Sets the `enabled` flag that allows creating a strong instance handle from
@@ -65,10 +65,9 @@ class EventTarget {
   Tag getTag() const;
 
  private:
+  const InstanceHandle::Shared instanceHandle_;
   mutable bool enabled_{false}; // Protected by `EventEmitter::DispatchMutex()`.
-  mutable jsi::WeakObject weakInstanceHandle_; // Protected by `jsi::Runtime &`.
   mutable jsi::Value strongInstanceHandle_; // Protected by `jsi::Runtime &`.
-  Tag tag_;
 };
 
 using SharedEventTarget = std::shared_ptr<const EventTarget>;

packages/react-native/ReactCommon/react/renderer/core/InstanceHandle.cpp

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include "InstanceHandle.h"
+
+namespace facebook::react {
+
+InstanceHandle::InstanceHandle(
+    jsi::Runtime &runtime,
+    jsi::Value const &instanceHandle,
+    Tag tag)
+    : weakInstanceHandle_(
+          jsi::WeakObject(runtime, instanceHandle.asObject(runtime))),
+      tag_(tag) {}
+
+jsi::Value InstanceHandle::getInstanceHandle(jsi::Runtime &runtime) const {
+  return weakInstanceHandle_.lock(runtime);
+}
+
+Tag InstanceHandle::getTag() const {
+  return tag_;
+}
+
+} // namespace facebook::react

packages/react-native/ReactCommon/react/renderer/core/InstanceHandle.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include <jsi/jsi.h>
+#include <react/renderer/core/ReactPrimitives.h>
+#include <memory>
+
+namespace facebook::react {
+
+class InstanceHandle {
+ public:
+  using Shared = std::shared_ptr<const InstanceHandle>;
+
+  InstanceHandle(
+      jsi::Runtime &runtime,
+      jsi::Value const &instanceHandle,
+      Tag tag);
+
+  /*
+   * Creates and returns the `instanceHandle`.
+   * Returns `null` if the `instanceHandle` is not retained at this moment.
+   */
+  jsi::Value getInstanceHandle(jsi::Runtime &runtime) const;
+
+  /*
+   * Deprecated. Do not use.
+   */
+  Tag getTag() const;
+
+ private:
+  const jsi::WeakObject weakInstanceHandle_; // Protected by `jsi::Runtime &`.
+  const Tag tag_;
+};
+
+} // namespace facebook::react

packages/react-native/ReactCommon/react/renderer/core/ReactPrimitives.h

@@ -17,8 +17,6 @@ namespace facebook::react {
  * `Tag` and `InstanceHandle` are used to address React Native components.
  */
 using Tag = int32_t;
-using InstanceHandle = struct InstanceHandleDummyStruct {
-} *;
 
 /*
  * An id of a running Surface instance that is used to refer to the instance.

packages/react-native/ReactCommon/react/renderer/core/ShadowNode.cpp

@@ -174,6 +174,15 @@ const SharedEventEmitter &ShadowNode::getEventEmitter() const {
   return family_->eventEmitter_;
 }
 
+jsi::Value ShadowNode::getInstanceHandle(jsi::Runtime &runtime) const {
+  auto instanceHandle = family_->instanceHandle_;
+  if (instanceHandle == nullptr) {
+    return jsi::Value::null();
+  }
+
+  return instanceHandle->getInstanceHandle(runtime);
+}
+
 Tag ShadowNode::getTag() const {
   return family_->tag_;
 }

packages/react-native/ReactCommon/react/renderer/core/ShadowNode.h

@@ -123,6 +123,7 @@ class ShadowNode : public Sealable,
   Props::Shared const &getProps() const;
   ListOfShared const &getChildren() const;
   SharedEventEmitter const &getEventEmitter() const;
+  jsi::Value getInstanceHandle(jsi::Runtime &runtime) const;
   Tag getTag() const;
   SurfaceId getSurfaceId() const;
 

packages/react-native/ReactCommon/react/renderer/core/ShadowNodeFamily.cpp

@@ -25,7 +25,9 @@ ShadowNodeFamily::ShadowNodeFamily(
     : eventDispatcher_(std::move(eventDispatcher)),
       tag_(fragment.tag),
       surfaceId_(fragment.surfaceId),
-      eventEmitter_(fragment.eventEmitter),
+      instanceHandle_(fragment.instanceHandle),
+      eventEmitter_(
+          componentDescriptor.createEventEmitter(fragment.instanceHandle)),
       componentDescriptor_(componentDescriptor),
       componentHandle_(componentDescriptor.getComponentHandle()),
       componentName_(componentDescriptor.getComponentName()) {}

packages/react-native/ReactCommon/react/renderer/core/ShadowNodeFamily.h

@@ -13,6 +13,7 @@
 #include <butter/small_vector.h>
 
 #include <react/renderer/core/EventEmitter.h>
+#include <react/renderer/core/InstanceHandle.h>
 #include <react/renderer/core/ReactPrimitives.h>
 
 namespace facebook::react {
@@ -36,7 +37,7 @@ class State;
 struct ShadowNodeFamilyFragment {
   Tag const tag;
   SurfaceId const surfaceId;
-  EventEmitter::Shared const &eventEmitter;
+  InstanceHandle::Shared const &instanceHandle;
 };
 
 /*
@@ -137,6 +138,11 @@ class ShadowNodeFamily final {
    */
   SurfaceId const surfaceId_;
 
+  /*
+   * Weak reference to the React instance handle
+   */
+  InstanceHandle::Shared const instanceHandle_;
+
   /*
    * `EventEmitter` associated with all nodes of the family.
    */

packages/react-native/ReactCommon/react/renderer/core/tests/ComponentDescriptorTest.cpp

@@ -29,13 +29,11 @@ TEST(ComponentDescriptorTest, createShadowNode) {
   const auto &raw = RawProps(folly::dynamic::object("nativeID", "abc"));
   Props::Shared props = descriptor->cloneProps(parserContext, nullptr, raw);
 
-  auto family = descriptor->createFamily(
-      ShadowNodeFamilyFragment{
-          /* .tag = */ 9,
-          /* .surfaceId = */ 1,
-          /* .eventEmitter = */ nullptr,
-      },
-      nullptr);
+  auto family = descriptor->createFamily(ShadowNodeFamilyFragment{
+      /* .tag = */ 9,
+      /* .surfaceId = */ 1,
+      /* .instanceHandle = */ nullptr,
+  });
 
   ShadowNode::Shared node = descriptor->createShadowNode(
       ShadowNodeFragment{
@@ -62,13 +60,11 @@ TEST(ComponentDescriptorTest, cloneShadowNode) {
 
   const auto &raw = RawProps(folly::dynamic::object("nativeID", "abc"));
   Props::Shared props = descriptor->cloneProps(parserContext, nullptr, raw);
-  auto family = descriptor->createFamily(
-      ShadowNodeFamilyFragment{
-          /* .tag = */ 9,
-          /* .surfaceId = */ 1,
-          /* .eventEmitter = */ nullptr,
-      },
-      nullptr);
+  auto family = descriptor->createFamily(ShadowNodeFamilyFragment{
+      /* .tag = */ 9,
+      /* .surfaceId = */ 1,
+      /* .instanceHandle = */ nullptr,
+  });
   ShadowNode::Shared node = descriptor->createShadowNode(
       ShadowNodeFragment{
           /* .props = */ props,
@@ -97,37 +93,31 @@ TEST(ComponentDescriptorTest, appendChild) {
 
   const auto &raw = RawProps(folly::dynamic::object("nativeID", "abc"));
   Props::Shared props = descriptor->cloneProps(parserContext, nullptr, raw);
-  auto family1 = descriptor->createFamily(
-      ShadowNodeFamilyFragment{
-          /* .tag = */ 1,
-          /* .surfaceId = */ 1,
-          /* .eventEmitter = */ nullptr,
-      },
-      nullptr);
+  auto family1 = descriptor->createFamily(ShadowNodeFamilyFragment{
+      /* .tag = */ 1,
+      /* .surfaceId = */ 1,
+      /* .instanceHandle = */ nullptr,
+  });
   ShadowNode::Shared node1 = descriptor->createShadowNode(
       ShadowNodeFragment{
           /* .props = */ props,
       },
       family1);
-  auto family2 = descriptor->createFamily(
-      ShadowNodeFamilyFragment{
-          /* .tag = */ 2,
-          /* .surfaceId = */ 1,
-          /* .eventEmitter = */ nullptr,
-      },
-      nullptr);
+  auto family2 = descriptor->createFamily(ShadowNodeFamilyFragment{
+      /* .tag = */ 2,
+      /* .surfaceId = */ 1,
+      /* .instanceHandle = */ nullptr,
+  });
   ShadowNode::Shared node2 = descriptor->createShadowNode(
       ShadowNodeFragment{
           /* .props = */ props,
       },
       family2);
-  auto family3 = descriptor->createFamily(
-      ShadowNodeFamilyFragment{
-          /* .tag = */ 3,
-          /* .surfaceId = */ 1,
-          /* .eventEmitter = */ nullptr,
-      },
-      nullptr);
+  auto family3 = descriptor->createFamily(ShadowNodeFamilyFragment{
+      /* .tag = */ 3,
+      /* .surfaceId = */ 1,
+      /* .instanceHandle = */ nullptr,
+  });
   ShadowNode::Shared node3 = descriptor->createShadowNode(
       ShadowNodeFragment{
           /* .props = */ props,

packages/react-native/ReactCommon/react/renderer/core/tests/ShadowNodeTest.cpp

@@ -41,7 +41,7 @@ class ShadowNodeTest : public ::testing::Test {
         ShadowNodeFamilyFragment{
             /* .tag = */ 11,
             /* .surfaceId = */ surfaceId_,
-            /* .eventEmitter = */ nullptr,
+            /* .instanceHandle = */ nullptr,
         },
         eventDispatcher_,
         componentDescriptor_);
@@ -57,7 +57,7 @@ class ShadowNodeTest : public ::testing::Test {
         ShadowNodeFamilyFragment{
             /* .tag = */ 12,
             /* .surfaceId = */ surfaceId_,
-            /* .eventEmitter = */ nullptr,
+            /* .instanceHandle = */ nullptr,
         },
         eventDispatcher_,
         componentDescriptor_);
@@ -73,7 +73,7 @@ class ShadowNodeTest : public ::testing::Test {
         ShadowNodeFamilyFragment{
             /* .tag = */ 13,
             /* .surfaceId = */ surfaceId_,
-            /* .eventEmitter = */ nullptr,
+            /* .instanceHandle = */ nullptr,
         },
         eventDispatcher_,
         componentDescriptor_);
@@ -92,7 +92,7 @@ class ShadowNodeTest : public ::testing::Test {
         ShadowNodeFamilyFragment{
             /* .tag = */ 15,
             /* .surfaceId = */ surfaceId_,
-            /* .eventEmitter = */ nullptr,
+            /* .instanceHandle = */ nullptr,
         },
         eventDispatcher_,
         componentDescriptor_);
@@ -108,7 +108,7 @@ class ShadowNodeTest : public ::testing::Test {
         ShadowNodeFamilyFragment{
             /* .tag = */ 16,
             /* .surfaceId = */ surfaceId_,
-            /* .eventEmitter = */ nullptr,
+            /* .instanceHandle = */ nullptr,
         },
         eventDispatcher_,
         componentDescriptor_);
@@ -127,7 +127,7 @@ class ShadowNodeTest : public ::testing::Test {
         ShadowNodeFamilyFragment{
             /* .tag = */ 17,
             /* .surfaceId = */ surfaceId_,
-            /* .eventEmitter = */ nullptr,
+            /* .instanceHandle = */ nullptr,
         },
         eventDispatcher_,
         componentDescriptor_);
@@ -143,7 +143,7 @@ class ShadowNodeTest : public ::testing::Test {
         ShadowNodeFamilyFragment{
             /* .tag = */ 18,
             /* .surfaceId = */ surfaceId_,
-            /* .eventEmitter = */ nullptr,
+            /* .instanceHandle = */ nullptr,
         },
         eventDispatcher_,
         componentDescriptor_);
@@ -174,7 +174,7 @@ TEST_F(ShadowNodeTest, handleShadowNodeCreation) {
   EXPECT_STREQ(nodeZ_->getComponentName(), "Test");
   EXPECT_EQ(nodeZ_->getTag(), 18);
   EXPECT_EQ(nodeZ_->getSurfaceId(), surfaceId_);
-  EXPECT_EQ(nodeZ_->getEventEmitter(), nullptr);
+  EXPECT_NE(nodeZ_->getEventEmitter(), nullptr);
   EXPECT_EQ(nodeZ_->getChildren().size(), 0);
 }
 
@@ -238,7 +238,7 @@ TEST_F(ShadowNodeTest, handleState) {
       ShadowNodeFamilyFragment{
           /* .tag = */ 9,
           /* .surfaceId = */ surfaceId_,
-          /* .eventEmitter = */ nullptr,
+          /* .instanceHandle = */ nullptr,
       },
       eventDispatcher_,
       componentDescriptor_);

packages/react-native/ReactCommon/react/renderer/element/ComponentBuilder.cpp

@@ -26,10 +26,8 @@ ShadowNode::Unshared ComponentBuilder::build(
     children.push_back(build(childFragment));
   }
 
-  auto family = componentDescriptor.createFamily(
-      ShadowNodeFamilyFragment{
-          elementFragment.tag, elementFragment.surfaceId, nullptr},
-      nullptr);
+  auto family = componentDescriptor.createFamily(ShadowNodeFamilyFragment{
+      elementFragment.tag, elementFragment.surfaceId, nullptr});
 
   auto initialState =
       componentDescriptor.createInitialState(elementFragment.props, family);

packages/react-native/ReactCommon/react/renderer/mounting/ShadowTree.cpp

@@ -225,9 +225,6 @@ ShadowTree::ShadowTree(
     ShadowTreeDelegate const &delegate,
     ContextContainer const &contextContainer)
     : surfaceId_(surfaceId), delegate_(delegate) {
-  const auto noopEventEmitter = std::make_shared<const ViewEventEmitter>(
-      nullptr, -1, std::shared_ptr<const EventDispatcher>());
-
   static auto globalRootComponentDescriptor =
       std::make_unique<RootComponentDescriptor const>(
           ComponentDescriptorParameters{
@@ -239,9 +236,8 @@ ShadowTree::ShadowTree(
       layoutConstraints,
       layoutContext);
 
-  auto const fragment =
-      ShadowNodeFamilyFragment{surfaceId, surfaceId, noopEventEmitter};
-  auto family = globalRootComponentDescriptor->createFamily(fragment, nullptr);
+  auto const fragment = ShadowNodeFamilyFragment{surfaceId, surfaceId, nullptr};
+  auto family = globalRootComponentDescriptor->createFamily(fragment);
 
   auto rootShadowNode = std::static_pointer_cast<const RootShadowNode>(
       globalRootComponentDescriptor->createShadowNode(

packages/react-native/ReactCommon/react/renderer/mounting/tests/MountingTest.cpp

@@ -53,7 +53,7 @@ static ShadowNode::Shared makeNode(
   return componentDescriptor.createShadowNode(
       ShadowNodeFragment{
           props, std::make_shared<ShadowNode::ListOfShared>(children)},
-      componentDescriptor.createFamily({tag, SurfaceId(1), nullptr}, nullptr));
+      componentDescriptor.createFamily({tag, SurfaceId(1), nullptr}));
 }
 
 /**
@@ -79,8 +79,8 @@ TEST(MountingTest, testReorderingInstructionGeneration) {
   auto rootComponentDescriptor =
       RootComponentDescriptor(componentDescriptorParameters);
 
-  auto rootFamily = rootComponentDescriptor.createFamily(
-      {Tag(1), SurfaceId(1), nullptr}, nullptr);
+  auto rootFamily =
+      rootComponentDescriptor.createFamily({Tag(1), SurfaceId(1), nullptr});
 
   // Creating an initial root shadow node.
   auto emptyRootNode = std::const_pointer_cast<RootShadowNode>(
@@ -110,8 +110,8 @@ TEST(MountingTest, testReorderingInstructionGeneration) {
   auto childJ = makeNode(viewComponentDescriptor, 109, {});
   auto childK = makeNode(viewComponentDescriptor, 110, {});
 
-  auto family = viewComponentDescriptor.createFamily(
-      {10, SurfaceId(1), nullptr}, nullptr);
+  auto family =
+      viewComponentDescriptor.createFamily({10, SurfaceId(1), nullptr});
 
   // Construct "identical" shadow nodes: they differ only in children.
   auto shadowNodeV1 = viewComponentDescriptor.createShadowNode(
@@ -390,8 +390,8 @@ TEST(MountingTest, testViewReparentingInstructionGeneration) {
   auto rootComponentDescriptor =
       RootComponentDescriptor(componentDescriptorParameters);
 
-  auto rootFamily = rootComponentDescriptor.createFamily(
-      {Tag(1), SurfaceId(1), nullptr}, nullptr);
+  auto rootFamily =
+      rootComponentDescriptor.createFamily({Tag(1), SurfaceId(1), nullptr});
 
   // Creating an initial root shadow node.
   auto emptyRootNode = std::const_pointer_cast<RootShadowNode>(
@@ -422,8 +422,8 @@ TEST(MountingTest, testViewReparentingInstructionGeneration) {
   auto childJ = makeNode(viewComponentDescriptor, 109, {});
   auto childK = makeNode(viewComponentDescriptor, 110, {});
 
-  auto family = viewComponentDescriptor.createFamily(
-      {10, SurfaceId(1), nullptr}, nullptr);
+  auto family =
+      viewComponentDescriptor.createFamily({10, SurfaceId(1), nullptr});
 
   auto reparentedViewA = makeNode(
       viewComponentDescriptor,

packages/react-native/ReactCommon/react/renderer/mounting/tests/ShadowTreeLifeCycleTest.cpp

@@ -42,8 +42,6 @@ static void testShadowNodeTreeLifeCycle(
       ViewComponentDescriptor(componentDescriptorParameters);
   auto rootComponentDescriptor =
       RootComponentDescriptor(componentDescriptorParameters);
-  auto noopEventEmitter =
-      std::make_shared<ViewEventEmitter const>(nullptr, -1, eventDispatcher);
 
   PropsParserContext parserContext{-1, *contextContainer};
 
@@ -52,8 +50,8 @@ static void testShadowNodeTreeLifeCycle(
   for (int i = 0; i < repeats; i++) {
     allNodes.clear();
 
-    auto family = rootComponentDescriptor.createFamily(
-        {Tag(1), SurfaceId(1), nullptr}, nullptr);
+    auto family =
+        rootComponentDescriptor.createFamily({Tag(1), SurfaceId(1), nullptr});
 
     // Creating an initial root shadow node.
     auto emptyRootNode = std::const_pointer_cast<RootShadowNode>(
@@ -195,8 +193,6 @@ static void testShadowNodeTreeLifeCycleExtensiveFlatteningUnflattening(
       ViewComponentDescriptor(componentDescriptorParameters);
   auto rootComponentDescriptor =
       RootComponentDescriptor(componentDescriptorParameters);
-  auto noopEventEmitter =
-      std::make_shared<ViewEventEmitter const>(nullptr, -1, eventDispatcher);
 
   PropsParserContext parserContext{-1, *contextContainer};
 
@@ -205,8 +201,8 @@ static void testShadowNodeTreeLifeCycleExtensiveFlatteningUnflattening(
   for (int i = 0; i < repeats; i++) {
     allNodes.clear();
 
-    auto family = rootComponentDescriptor.createFamily(
-        {Tag(1), SurfaceId(1), nullptr}, nullptr);
+    auto family =
+        rootComponentDescriptor.createFamily({Tag(1), SurfaceId(1), nullptr});
 
     // Creating an initial root shadow node.
     auto emptyRootNode = std::const_pointer_cast<RootShadowNode>(

packages/react-native/ReactCommon/react/renderer/uimanager/UIManager.cpp

@@ -68,7 +68,7 @@ ShadowNode::Shared UIManager::createNode(
     std::string const &name,
     SurfaceId surfaceId,
     const RawProps &rawProps,
-    SharedEventTarget eventTarget) const {
+    const InstanceHandle::Shared &instanceHandle) const {
   SystraceSection s("UIManager::createNode");
 
   auto &componentDescriptor = componentDescriptorRegistry_->at(name);
@@ -77,9 +77,9 @@ ShadowNode::Shared UIManager::createNode(
 
   PropsParserContext propsParserContext{surfaceId, *contextContainer_.get()};
 
-  auto const fragment = ShadowNodeFamilyFragment{tag, surfaceId, nullptr};
-  auto family =
-      componentDescriptor.createFamily(fragment, std::move(eventTarget));
+  auto const fragment =
+      ShadowNodeFamilyFragment{tag, surfaceId, instanceHandle};
+  auto family = componentDescriptor.createFamily(fragment);
   auto const props =
       componentDescriptor.cloneProps(propsParserContext, nullptr, rawProps);
   auto const state = componentDescriptor.createInitialState(props, family);

packages/react-native/ReactCommon/react/renderer/uimanager/UIManager.h

@@ -14,6 +14,7 @@
 #include <shared_mutex>
 
 #include <react/renderer/componentregistry/ComponentDescriptorRegistry.h>
+#include <react/renderer/core/InstanceHandle.h>
 #include <react/renderer/core/RawValue.h>
 #include <react/renderer/core/ShadowNode.h>
 #include <react/renderer/core/StateData.h>
@@ -134,7 +135,7 @@ class UIManager final : public ShadowTreeDelegate {
       std::string const &componentName,
       SurfaceId surfaceId,
       const RawProps &props,
-      SharedEventTarget eventTarget) const;
+      const InstanceHandle::Shared &instanceHandle) const;
 
   ShadowNode::Shared cloneNode(
       ShadowNode const &shadowNode,

packages/react-native/ReactCommon/react/renderer/uimanager/UIManagerBinding.cpp

@@ -186,12 +186,13 @@ jsi::Value UIManagerBinding::get(
             jsi::Value const & /*thisValue*/,
             jsi::Value const *arguments,
             size_t /*count*/) noexcept -> jsi::Value {
-          auto eventTarget =
-              eventTargetFromValue(runtime, arguments[4], arguments[0]);
-          if (!eventTarget) {
+          auto instanceHandle =
+              instanceHandleFromValue(runtime, arguments[4], arguments[0]);
+          if (!instanceHandle) {
             react_native_assert(false);
             return jsi::Value::undefined();
           }
+
           return valueFromShadowNode(
               runtime,
               uiManager->createNode(
@@ -199,7 +200,7 @@ jsi::Value UIManagerBinding::get(
                   stringFromValue(runtime, arguments[1]),
                   surfaceIdFromValue(runtime, arguments[2]),
                   RawProps(runtime, arguments[3]),
-                  eventTarget));
+                  instanceHandle));
         });
   }
 
@@ -798,7 +799,7 @@ jsi::Value UIManagerBinding::get(
             return jsi::Value::null();
           }
 
-          return getInstanceHandleFromShadowNode(parentShadowNode, runtime);
+          return (*parentShadowNode).getInstanceHandle(runtime);
         });
   }
 
@@ -1006,8 +1007,7 @@ jsi::Value UIManagerBinding::get(
 
           return jsi::Array::createWithElements(
               runtime,
-              getInstanceHandleFromShadowNode(
-                  newestParentOfShadowNode, runtime),
+              (*newestParentOfShadowNode).getInstanceHandle(runtime),
               jsi::Value{runtime, (double)offsetTop},
               jsi::Value{runtime, (double)offsetLeft});
         });

packages/react-native/ReactCommon/react/renderer/uimanager/primitives.h

@@ -142,16 +142,16 @@ inline static Tag tagFromValue(jsi::Value const &value) {
   return (Tag)value.getNumber();
 }
 
-inline static SharedEventTarget eventTargetFromValue(
+inline static InstanceHandle::Shared instanceHandleFromValue(
     jsi::Runtime &runtime,
-    jsi::Value const &eventTargetValue,
+    jsi::Value const &instanceHandleValue,
     jsi::Value const &tagValue) {
-  react_native_assert(!eventTargetValue.isNull());
-  if (eventTargetValue.isNull()) {
+  react_native_assert(!instanceHandleValue.isNull());
+  if (instanceHandleValue.isNull()) {
     return nullptr;
   }
-  return std::make_shared<EventTarget>(
-      runtime, eventTargetValue, tagFromValue(tagValue));
+  return std::make_shared<InstanceHandle>(
+      runtime, instanceHandleValue, tagFromValue(tagValue));
 }
 
 inline static SurfaceId surfaceIdFromValue(
@@ -185,21 +185,6 @@ inline static folly::dynamic commandArgsFromValue(
   return jsi::dynamicFromValue(runtime, value);
 }
 
-inline static jsi::Value getInstanceHandleFromShadowNode(
-    ShadowNode::Shared shadowNode,
-    jsi::Runtime &runtime) {
-  auto eventTarget = shadowNode->getEventEmitter()->getEventTarget();
-  // shadowNode is probably a RootShadowNode and they don't have
-  // event targets.
-  if (eventTarget == nullptr) {
-    return jsi::Value::null();
-  }
-  eventTarget->retain(runtime);
-  auto instanceHandle = eventTarget->getInstanceHandle(runtime);
-  eventTarget->release(runtime);
-  return instanceHandle;
-}
-
 inline static jsi::Value getArrayOfInstanceHandlesFromShadowNodes(
     ShadowNode::ListOfShared const &nodes,
     jsi::Runtime &runtime) {
@@ -209,7 +194,7 @@ inline static jsi::Value getArrayOfInstanceHandlesFromShadowNodes(
   std::vector<jsi::Value> nonNullInstanceHandles;
   nonNullInstanceHandles.reserve(nodes.size());
   for (auto const &shadowNode : nodes) {
-    auto instanceHandle = getInstanceHandleFromShadowNode(shadowNode, runtime);
+    auto instanceHandle = (*shadowNode).getInstanceHandle(runtime);
     if (!instanceHandle.isNull()) {
       nonNullInstanceHandles.push_back(std::move(instanceHandle));
     }

packages/react-native/ReactCommon/react/test_utils/shadowTreeGeneration.h

@@ -290,7 +290,7 @@ static inline ShadowNode::Shared generateShadowNodeTree(
     int deviation = 3) {
   if (size <= 1) {
     auto family = componentDescriptor.createFamily(
-        {generateReactTag(), SurfaceId(1), nullptr}, nullptr);
+        {generateReactTag(), SurfaceId(1), nullptr});
     return componentDescriptor.createShadowNode(
         ShadowNodeFragment{generateDefaultProps(componentDescriptor)}, family);
   }
@@ -306,7 +306,7 @@ static inline ShadowNode::Shared generateShadowNodeTree(
   }
 
   auto family = componentDescriptor.createFamily(
-      {generateReactTag(), SurfaceId(1), nullptr}, nullptr);
+      {generateReactTag(), SurfaceId(1), nullptr});
   return componentDescriptor.createShadowNode(
       ShadowNodeFragment{
           generateDefaultProps(componentDescriptor),