IntersectionObserver: Migrate js infra to shadow node family (#51148)

Summary:
Pull Request resolved: #51148

Intersection observer should not be holding on to shadow nodes.

This diff migrates the javascript infra to instead use families.

Changelog: [Internal]

Reviewed By: yungsters

Differential Revision: D74262804

fbshipit-source-id: cc090be54f7312ce32b853ddf86567bb43e676b8

Author: RSNara

packages/react-native/ReactCommon/react/nativemodule/intersectionobserver/NativeIntersectionObserver.cpp

@@ -21,35 +21,76 @@ NativeIntersectionObserverModuleProvider(
 
 namespace facebook::react {
 
+namespace {
+
+jsi::Object tokenFromShadowNodeFamily(
+    jsi::Runtime& runtime,
+    ShadowNodeFamily::Shared shadowNodeFamily) {
+  jsi::Object obj(runtime);
+  // Need to const_cast since JSI only allows non-const pointees
+  obj.setNativeState(
+      runtime,
+      std::const_pointer_cast<ShadowNodeFamily>(std::move(shadowNodeFamily)));
+  return obj;
+}
+
+ShadowNodeFamily::Shared shadowNodeFamilyFromToken(
+    jsi::Runtime& runtime,
+    jsi::Object token) {
+  return token.getNativeState<ShadowNodeFamily>(runtime);
+}
+
+} // namespace
+
 NativeIntersectionObserver::NativeIntersectionObserver(
     std::shared_ptr<CallInvoker> jsInvoker)
     : NativeIntersectionObserverCxxSpec(std::move(jsInvoker)) {}
 
 void NativeIntersectionObserver::observe(
     jsi::Runtime& runtime,
     NativeIntersectionObserverObserveOptions options) {
+  observeV2(runtime, std::move(options));
+}
+
+void NativeIntersectionObserver::unobserve(
+    jsi::Runtime& runtime,
+    IntersectionObserverObserverId intersectionObserverId,
+    jsi::Object targetShadowNode) {
+  auto shadowNode = shadowNodeFromValue(runtime, std::move(targetShadowNode));
+  auto token =
+      tokenFromShadowNodeFamily(runtime, shadowNode->getFamilyShared());
+  unobserveV2(runtime, intersectionObserverId, std::move(token));
+}
+
+jsi::Object NativeIntersectionObserver::observeV2(
+    jsi::Runtime& runtime,
+    NativeIntersectionObserverObserveOptions options) {
   auto intersectionObserverId = options.intersectionObserverId;
   auto shadowNode =
       shadowNodeFromValue(runtime, std::move(options.targetShadowNode));
+  auto shadowNodeFamily = shadowNode->getFamilyShared();
   auto thresholds = options.thresholds;
   auto rootThresholds = options.rootThresholds;
   auto& uiManager = getUIManagerFromRuntime(runtime);
 
   intersectionObserverManager_.observe(
       intersectionObserverId,
-      shadowNode->getFamilyShared(),
+      shadowNodeFamily,
       thresholds,
       rootThresholds,
       uiManager);
+
+  return tokenFromShadowNodeFamily(runtime, shadowNodeFamily);
 }
 
-void NativeIntersectionObserver::unobserve(
+void NativeIntersectionObserver::unobserveV2(
     jsi::Runtime& runtime,
     IntersectionObserverObserverId intersectionObserverId,
-    jsi::Object targetShadowNode) {
-  auto shadowNode = shadowNodeFromValue(runtime, std::move(targetShadowNode));
+    jsi::Object targetToken) {
+  auto shadowNodeFamily =
+      shadowNodeFamilyFromToken(runtime, std::move(targetToken));
   intersectionObserverManager_.unobserve(
-      intersectionObserverId, shadowNode->getFamilyShared());
+      intersectionObserverId, shadowNodeFamily);
 }
 
 void NativeIntersectionObserver::connect(

packages/react-native/ReactCommon/react/nativemodule/intersectionobserver/NativeIntersectionObserver.h

@@ -61,15 +61,28 @@ class NativeIntersectionObserver
  public:
   NativeIntersectionObserver(std::shared_ptr<CallInvoker> jsInvoker);
 
+  // TODO(T223605846): Remove legacy observe method
+  [[deprecated("Please use observeV2")]]
   void observe(
       jsi::Runtime& runtime,
       NativeIntersectionObserverObserveOptions options);
 
+  // TODO(T223605846): Remove legacy unobserve method
+  [[deprecated("Please use unobserveV2")]]
   void unobserve(
       jsi::Runtime& runtime,
       IntersectionObserverObserverId intersectionObserverId,
       jsi::Object targetShadowNode);
 
+  jsi::Object observeV2(
+      jsi::Runtime& runtime,
+      NativeIntersectionObserverObserveOptions options);
+
+  void unobserveV2(
+      jsi::Runtime& runtime,
+      IntersectionObserverObserverId intersectionObserverId,
+      jsi::Object targetToken);
+
   void connect(
       jsi::Runtime& runtime,
       AsyncCallback<> notifyIntersectionObserversCallback);

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

@@ -39,7 +39,7 @@ struct ShadowNodeFamilyFragment {
  * Represents all things that shadow nodes from the same family have in common.
  * To be used inside `ShadowNode` class *only*.
  */
-class ShadowNodeFamily final {
+class ShadowNodeFamily final : public jsi::NativeState {
  public:
   using Shared = std::shared_ptr<const ShadowNodeFamily>;
   using Weak = std::weak_ptr<const ShadowNodeFamily>;

packages/react-native/scripts/featureflags/ReactNativeFeatureFlags.config.js

@@ -663,6 +663,16 @@ const definitions: FeatureFlagDefinitions = {
       },
       ossReleaseStage: 'none',
     },
+    utilizeTokensInIntersectionObserver: {
+      defaultValue: true,
+      metadata: {
+        dateAdded: '2025-05-06',
+        description: 'Use tokens in IntersectionObserver vs ShadowNode.',
+        expectedReleaseValue: true,
+        purpose: 'experimentation',
+      },
+      ossReleaseStage: 'none',
+    },
   },
 };
 

packages/react-native/src/private/featureflags/ReactNativeFeatureFlags.js

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<6667fc8e4fdd2db0b54c908155b110cf>>
+ * @generated SignedSource<<17fa5e03fe52ed129cf731bba6e9869c>>
  * @flow strict
  */
 
@@ -39,6 +39,7 @@ export type ReactNativeFeatureFlagsJsOnly = $ReadOnly<{
   shouldUseAnimatedObjectForTransform: Getter<boolean>,
   shouldUseRemoveClippedSubviewsAsDefaultOnIOS: Getter<boolean>,
   shouldUseSetNativePropsInFabric: Getter<boolean>,
+  utilizeTokensInIntersectionObserver: Getter<boolean>,
 }>;
 
 export type ReactNativeFeatureFlagsJsOnlyOverrides = OverridesFor<ReactNativeFeatureFlagsJsOnly>;
@@ -155,6 +156,11 @@ export const shouldUseRemoveClippedSubviewsAsDefaultOnIOS: Getter<boolean> = cre
  */
 export const shouldUseSetNativePropsInFabric: Getter<boolean> = createJavaScriptFlagGetter('shouldUseSetNativePropsInFabric', true);
 
+/**
+ * Use tokens in IntersectionObserver vs ShadowNode.
+ */
+export const utilizeTokensInIntersectionObserver: Getter<boolean> = createJavaScriptFlagGetter('utilizeTokensInIntersectionObserver', true);
+
 /**
  * Common flag for testing. Do NOT modify.
  */

packages/react-native/src/private/webapis/intersectionobserver/__tests__/IntersectionObserver-itest.js

@@ -7,6 +7,7 @@
  * @flow strict-local
  * @format
  * @oncall react_native
+ * @fantom_flags utilizeTokensInIntersectionObserver:true
  */
 
 import 'react-native/Libraries/Core/InitializeCore';
@@ -844,8 +845,7 @@ describe('IntersectionObserver', () => {
       });
     });
 
-    // TODO (T223234714): Fix memory leak and enable this test.
-    it.skip('should not retain initial children of observed targets', () => {
+    it('should not retain initial children of observed targets', () => {
       const root = Fantom.createRoot();
       observer = new IntersectionObserver(() => {});
 

packages/react-native/src/private/webapis/intersectionobserver/internals/IntersectionObserverManager.js

@@ -23,9 +23,11 @@ import type IntersectionObserver, {
   IntersectionObserverCallback,
 } from '../IntersectionObserver';
 import type IntersectionObserverEntry from '../IntersectionObserverEntry';
+import type {NativeIntersectionObserverToken} from '../specs/NativeIntersectionObserver';
 
 import * as Systrace from '../../../../../Libraries/Performance/Systrace';
 import warnOnce from '../../../../../Libraries/Utilities/warnOnce';
+import * as ReactNativeFeatureFlags from '../../../featureflags/ReactNativeFeatureFlags';
 import {
   getInstanceHandle,
   getNativeNodeReference,
@@ -74,6 +76,26 @@ const targetToShadowNodeMap: WeakMap<
   ReturnType<typeof getNativeNodeReference>,
 > = new WeakMap();
 
+const targetToTokenMap: WeakMap<
+  ReactNativeElement,
+  NativeIntersectionObserverToken,
+> = new WeakMap();
+
+let modernNativeIntersectionObserver =
+  NativeIntersectionObserver == null
+    ? null
+    : NativeIntersectionObserver.observeV2 == null ||
+        NativeIntersectionObserver.unobserveV2 == null
+      ? null
+      : {
+          observe: NativeIntersectionObserver.observeV2,
+          unobserve: NativeIntersectionObserver.unobserveV2,
+        };
+
+if (!ReactNativeFeatureFlags.utilizeTokensInIntersectionObserver()) {
+  modernNativeIntersectionObserver = null;
+}
+
 /**
  * Registers the given intersection observer and returns a unique ID for it,
  * which is required to start observing targets.
@@ -153,20 +175,32 @@ export function observe({
   // access it even after the instance handle has been unmounted.
   setTargetForInstanceHandle(instanceHandle, target);
 
-  // Same for the mapping between the target and its shadow node.
-  targetToShadowNodeMap.set(target, targetNativeNodeReference);
+  if (modernNativeIntersectionObserver == null) {
+    // Same for the mapping between the target and its shadow node.
+    targetToShadowNodeMap.set(target, targetNativeNodeReference);
+  }
 
   if (!isConnected) {
     NativeIntersectionObserver.connect(notifyIntersectionObservers);
     isConnected = true;
   }
 
-  NativeIntersectionObserver.observe({
-    intersectionObserverId,
-    targetShadowNode: targetNativeNodeReference,
-    thresholds: registeredObserver.observer.thresholds,
-    rootThresholds: registeredObserver.observer.rnRootThresholds,
-  });
+  if (modernNativeIntersectionObserver == null) {
+    NativeIntersectionObserver.observe({
+      intersectionObserverId,
+      targetShadowNode: targetNativeNodeReference,
+      thresholds: registeredObserver.observer.thresholds,
+      rootThresholds: registeredObserver.observer.rnRootThresholds,
+    });
+  } else {
+    const token = modernNativeIntersectionObserver.observe({
+      intersectionObserverId,
+      targetShadowNode: targetNativeNodeReference,
+      thresholds: registeredObserver.observer.thresholds,
+      rootThresholds: registeredObserver.observer.rnRootThresholds,
+    });
+    targetToTokenMap.set(target, token);
+  }
 
   return true;
 }
@@ -190,18 +224,33 @@ export function unobserve(
     return;
   }
 
-  const targetNativeNodeReference = targetToShadowNodeMap.get(target);
-  if (targetNativeNodeReference == null) {
-    console.error(
-      'IntersectionObserverManager: could not find registration data for target',
+  if (modernNativeIntersectionObserver == null) {
+    const targetNativeNodeReference = targetToShadowNodeMap.get(target);
+    if (targetNativeNodeReference == null) {
+      console.error(
+        'IntersectionObserverManager: could not find registration data for target',
+      );
+      return;
+    }
+
+    NativeIntersectionObserver.unobserve(
+      intersectionObserverId,
+      targetNativeNodeReference,
     );
-    return;
-  }
+  } else {
+    const targetToken = targetToTokenMap.get(target);
+    if (targetToken == null) {
+      console.error(
+        'IntersectionObserverManager: could not find registration data for target',
+      );
+      return;
+    }
 
-  NativeIntersectionObserver.unobserve(
-    intersectionObserverId,
-    targetNativeNodeReference,
-  );
+    modernNativeIntersectionObserver.unobserve(
+      intersectionObserverId,
+      targetToken,
+    );
+  }
 }
 
 /**

packages/react-native/src/private/webapis/intersectionobserver/specs/NativeIntersectionObserver.js

@@ -30,9 +30,20 @@ export type NativeIntersectionObserverObserveOptions = {
   rootThresholds?: ?$ReadOnlyArray<number>,
 };
 
+export type NativeIntersectionObserverToken = mixed;
+
 export interface Spec extends TurboModule {
+  // TODO(T223605846): Remove legacy observe method
   +observe: (options: NativeIntersectionObserverObserveOptions) => void;
+  // TODO(T223605846): Remove legacy unobserve method
   +unobserve: (intersectionObserverId: number, targetShadowNode: mixed) => void;
+  +observeV2?: (
+    options: NativeIntersectionObserverObserveOptions,
+  ) => NativeIntersectionObserverToken;
+  +unobserveV2?: (
+    intersectionObserverId: number,
+    token: NativeIntersectionObserverToken,
+  ) => void;
   +connect: (notifyIntersectionObserversCallback: () => void) => void;
   +disconnect: () => void;
   +takeRecords: () => $ReadOnlyArray<NativeIntersectionObserverEntry>;