Avoid global JNI ref copies in FabricUIManager lookups

packages/react-native/ReactAndroid/src/main/jni/react/fabric/FabricUIManager.cpp

@@ -23,8 +23,8 @@ Size measureHostComponent(
     return {};
   }
 
-  const auto fabricUIManager =
-      contextContainer->at<jni::global_ref<jobject>>("FabricUIManager");
+  auto fabricUIManager =
+      contextContainer->at<jni::alias_ref<jobject>>("FabricUIManager");
   static const auto measure =
       jni::findClassStatic("com/facebook/react/fabric/FabricUIManager")
           ->getMethod<jlong(

packages/react-native/ReactAndroid/src/main/jni/react/fabric/FabricUIManagerBinding.cpp

@@ -609,7 +609,12 @@ void FabricUIManagerBinding::installFabricUIManager(
         globalJavaUiManager);
   };
 
-  contextContainer->insert("FabricUIManager", globalJavaUiManager);
+  auto fabricUIManagerOwner =
+      std::make_shared<jni::global_ref<jobject>>(globalJavaUiManager);
+  // The alias and its owner must stay registered for the container's lifetime.
+  contextContainer->insert("FabricUIManagerOwner", fabricUIManagerOwner);
+  contextContainer->insert(
+      "FabricUIManager", jni::alias_ref<jobject>(*fabricUIManagerOwner));
 
   animationChoreographer_ = std::make_shared<AndroidAnimationChoreographer>();
 

packages/react-native/ReactAndroid/src/main/jni/react/fabric/test_helper/FabricMountingManagerTestHelper.cpp

@@ -79,6 +79,63 @@ std::vector<Tag> toTags(jni::alias_ref<jni::JArrayInt> tags) {
   return {region.get(), region.get() + tags->size()};
 }
 
+bool fabricUIManagerAliasUsesOwnedHandle(
+    [[maybe_unused]] jni::alias_ref<jclass> javaClass,
+    jni::alias_ref<JFabricUIManager::javaobject> javaUIManager) {
+  auto contextContainer =
+      javaUIManager->getBinding()->getScheduler()->getContextContainer();
+  auto owner = contextContainer->at<std::shared_ptr<jni::global_ref<jobject>>>(
+      "FabricUIManagerOwner");
+  auto alias = contextContainer->at<jni::alias_ref<jobject>>("FabricUIManager");
+  auto env = jni::Environment::current();
+  return alias.get() == owner->get() &&
+      env->GetObjectRefType(alias.get()) == JNIGlobalRefType &&
+      jni::isSameObject(alias.get(), javaUIManager.get());
+}
+
+jni::local_ref<JFabricUIManager::javaobject> readFabricUIManagerFromContext(
+    [[maybe_unused]] jni::alias_ref<jclass> javaClass,
+    jni::alias_ref<JFabricUIManager::javaobject> javaUIManager,
+    jboolean useGlobalRef,
+    jboolean uninstall) {
+  static const auto bindingField =
+      JFabricUIManager::javaClassStatic()
+          ->getField<FabricUIManagerBinding::javaobject>("mBinding");
+  static const auto unregister =
+      jni::findClassStatic("com/facebook/react/fabric/FabricUIManagerBinding")
+          ->getMethod<void()>("unregister");
+  auto javaBinding = javaUIManager->getFieldValue(bindingField);
+  auto contextContainer =
+      javaBinding->cthis()->getScheduler()->getContextContainer();
+  if (useGlobalRef != 0) {
+    auto global =
+        contextContainer->at<jni::global_ref<jobject>>("FabricUIManager");
+    if (uninstall != 0) {
+      std::weak_ptr<jni::global_ref<jobject>> owner =
+          contextContainer->at<std::shared_ptr<jni::global_ref<jobject>>>(
+              "FabricUIManagerOwner");
+      unregister(javaBinding);
+      contextContainer->erase("FabricUIManager");
+      contextContainer->erase("FabricUIManagerOwner");
+      if (!owner.expired()) {
+        jni::throwNewJavaException(
+            "java/lang/AssertionError",
+            "FabricUIManager owner survived teardown");
+      }
+      contextContainer.reset();
+    }
+    return jni::make_local(
+        jni::static_ref_cast<JFabricUIManager::javaobject>(
+            jni::alias_ref<jobject>(global)));
+  }
+  if (uninstall != 0) {
+    unregister(javaBinding);
+  }
+  auto alias = contextContainer->at<jni::alias_ref<jobject>>("FabricUIManager");
+  return jni::make_local(
+      jni::static_ref_cast<JFabricUIManager::javaobject>(alias));
+}
+
 } // namespace
 
 FabricMountingManagerTestHelper::FabricMountingManagerTestHelper(
@@ -402,6 +459,11 @@ FabricMountingManagerTestHelper::pulledDeleteTags() {
 
 void FabricMountingManagerTestHelper::registerNatives() {
   registerHybrid({
+      makeNativeMethod(
+          "fabricUIManagerAliasUsesOwnedHandle",
+          fabricUIManagerAliasUsesOwnedHandle),
+      makeNativeMethod(
+          "readFabricUIManagerFromContext", readFabricUIManagerFromContext),
       makeNativeMethod(
           "initHybrid", FabricMountingManagerTestHelper::initHybrid),
       makeNativeMethod(

packages/react-native/ReactAndroid/src/test/java/com/facebook/react/fabric/FabricMountingManagerInstrumentationTest.kt

@@ -252,7 +252,7 @@ class FabricMountingManagerInstrumentationTest {
   }
 
   private fun mountPaddedView(
-      fixTextLayoutOnPixelDensityChange: Boolean
+      fixTextLayoutOnPixelDensityChange: Boolean,
   ): Pair<FabricMountingManagerTestHelper, ReactViewGroup> {
     val fabricUIManager = createFabricUIManager(listOf(PaddingViewManager()))
     val helper = FabricMountingManagerTestHelper.create(fabricUIManager)
@@ -281,7 +281,7 @@ class FabricMountingManagerInstrumentationTest {
     ReactNativeFeatureFlagsCxxInterop.dangerouslyForceOverride(
         object : ReactNativeFeatureFlagsDefaults() {
           override fun enableMountingCoordinatorPullModelAndroid(): Boolean = true
-        }
+        },
     )
   }
 
@@ -501,7 +501,7 @@ class FabricMountingManagerInstrumentationTest {
           override fun enablePropsUpdateReconciliationAndroid(): Boolean = pullModel
 
           override fun enablePreallocatedPropsDiffOnInsertAndroid(): Boolean = pullModel
-        }
+        },
     )
   }
 
@@ -582,6 +582,71 @@ class FabricMountingManagerInstrumentationTest {
     return surfaceId to { fabricUIManager.stopSurface(surfaceId) }
   }
 
+  @Test
+  fun native_fabricUIManagerContext_aliasUsesOwnedGlobalHandle() {
+    val fabricUIManager = createFabricUIManager()
+    registerBinding(fabricUIManager)
+
+    assertThat(FabricMountingManagerTestHelper.fabricUIManagerAliasUsesOwnedHandle(fabricUIManager))
+        .isTrue()
+    assertThat(
+            FabricMountingManagerTestHelper.readFabricUIManagerFromContext(
+                fabricUIManager,
+                useGlobalRef = false,
+                uninstall = false,
+            ),
+        )
+        .isSameAs(fabricUIManager)
+  }
+
+  @Test
+  fun native_fabricUIManagerContext_legacyCopiesLeaveAliasValid() {
+    val fabricUIManager = createFabricUIManager()
+    registerBinding(fabricUIManager)
+
+    repeat(64) {
+      assertThat(
+              FabricMountingManagerTestHelper.readFabricUIManagerFromContext(
+                  fabricUIManager,
+                  useGlobalRef = true,
+                  uninstall = false,
+              ),
+          )
+          .isSameAs(fabricUIManager)
+      assertThat(
+              FabricMountingManagerTestHelper.fabricUIManagerAliasUsesOwnedHandle(fabricUIManager),
+          )
+          .isTrue()
+      assertThat(
+              FabricMountingManagerTestHelper.readFabricUIManagerFromContext(
+                  fabricUIManager,
+                  useGlobalRef = false,
+                  uninstall = false,
+              ),
+          )
+          .isSameAs(fabricUIManager)
+    }
+  }
+
+  @Test
+  fun native_fabricUIManagerContext_readsSurviveUninstall() {
+    for (useGlobalRef in listOf(false, true)) {
+      repeat(8) {
+        val fabricUIManager = createFabricUIManager()
+        registerBinding(fabricUIManager)
+
+        assertThat(
+                FabricMountingManagerTestHelper.readFabricUIManagerFromContext(
+                    fabricUIManager,
+                    useGlobalRef = useGlobalRef,
+                    uninstall = true,
+                ),
+            )
+            .isSameAs(fabricUIManager)
+      }
+    }
+  }
+
   @Test
   fun native_stopSurfaceWithSurfaceHandler_pullModel_pullsDeletes() {
     assertStoppingSurfacePullsDeletes(pullModel = true, ::startBridgelessSurface)

packages/react-native/ReactAndroid/src/test/java/com/facebook/react/fabric/FabricMountingManagerTestHelper.kt

@@ -90,6 +90,16 @@ private constructor(fabricUIManager: FabricUIManager) : HybridClassBase() {
       SoLoader.loadLibrary("fabricjni_test_helper")
     }
 
+    @JvmStatic
+    external fun fabricUIManagerAliasUsesOwnedHandle(fabricUIManager: FabricUIManager): Boolean
+
+    @JvmStatic
+    external fun readFabricUIManagerFromContext(
+        fabricUIManager: FabricUIManager,
+        useGlobalRef: Boolean,
+        uninstall: Boolean,
+    ): FabricUIManager
+
     @JvmStatic
     fun create(fabricUIManager: FabricUIManager): FabricMountingManagerTestHelper {
       return FabricMountingManagerTestHelper(fabricUIManager)

packages/react-native/ReactCommon/react/renderer/components/modal/ModalHostViewComponentDescriptor.cpp

@@ -21,8 +21,8 @@ State::Shared ModalHostViewComponentDescriptor::createInitialState(
 
   int surfaceId = family->getSurfaceId();
 
-  const jni::global_ref<jobject>& fabricUIManager =
-      contextContainer_->at<jni::global_ref<jobject>>("FabricUIManager");
+  auto fabricUIManager =
+      contextContainer_->at<jni::alias_ref<jobject>>("FabricUIManager");
 
   static auto getEncodedScreenSizeWithoutVerticalInsets =
       jni::findClassStatic(UIManagerJavaDescriptor)

packages/react-native/ReactCommon/react/renderer/components/textinput/platform/android/react/renderer/components/androidtextinput/AndroidTextInputComponentDescriptor.h

@@ -44,8 +44,7 @@ class AndroidTextInputComponentDescriptor final : public ConcreteComponentDescri
     if (surfaceIdToThemePaddingMap_.find(surfaceId) != surfaceIdToThemePaddingMap_.end()) {
       theme = surfaceIdToThemePaddingMap_[surfaceId];
     } else {
-      const jni::global_ref<jobject> &fabricUIManager =
-          contextContainer_->at<jni::global_ref<jobject>>("FabricUIManager");
+      auto fabricUIManager = contextContainer_->at<jni::alias_ref<jobject>>("FabricUIManager");
 
       auto env = jni::Environment::current();
       auto defaultTextInputPaddingArray = env->NewFloatArray(4);

packages/react-native/ReactCommon/react/renderer/graphics/platform/android/react/renderer/graphics/PlatformColorParser.cpp

@@ -91,8 +91,8 @@ SharedColor parsePlatformColor(
         if (iterator != getColorCache.end()) {
           resolvedColor = iterator->second;
         } else {
-          const auto& fabricUIManager =
-              contextContainer.at<jni::global_ref<jobject>>("FabricUIManager");
+          auto fabricUIManager =
+              contextContainer.at<jni::alias_ref<jobject>>("FabricUIManager");
           // Boxed Integer: null is an explicit miss; a non-null value may be 0
           // (transparent black).
           static auto getColorFromJava =

packages/react-native/ReactCommon/react/renderer/imagemanager/platform/android/react/renderer/imagemanager/ImageFetcher.cpp

@@ -48,7 +48,7 @@ void ImageFetcher::flushImageRequests() {
   }
 
   auto fabricUIManager_ =
-      contextContainer_->at<jni::global_ref<jobject>>("FabricUIManager");
+      contextContainer_->at<jni::alias_ref<jobject>>("FabricUIManager");
   static auto prefetchResources =
       fabricUIManager_->getClass()
           ->getMethod<void(

packages/react-native/ReactCommon/react/renderer/textlayoutmanager/platform/android/react/renderer/textlayoutmanager/TextLayoutManager.cpp

@@ -48,8 +48,8 @@ Size measureText(
     float minHeight,
     float maxHeight,
     jfloatArray attachmentPositions) {
-  const jni::global_ref<jobject>& fabricUIManager =
-      contextContainer->at<jni::global_ref<jobject>>("FabricUIManager");
+  auto fabricUIManager =
+      contextContainer->at<jni::alias_ref<jobject>>("FabricUIManager");
 
   static auto measure =
       jni::findClassStatic("com/facebook/react/fabric/FabricUIManager")
@@ -245,8 +245,8 @@ LinesMeasurements TextLayoutManager::measureLines(
   const auto& attributedString = attributedStringBox.getValue();
 
   auto doMeasureLines = [&]() {
-    const jni::global_ref<jobject>& fabricUIManager =
-        contextContainer_->at<jni::global_ref<jobject>>("FabricUIManager");
+    auto fabricUIManager =
+        contextContainer_->at<jni::alias_ref<jobject>>("FabricUIManager");
     static auto measureLines =
         jni::findClassStatic("com/facebook/react/fabric/FabricUIManager")
             ->getMethod<NativeArray::javaobject(
@@ -319,8 +319,8 @@ TextLayoutManager::PreparedTextLayout TextLayoutManager::prepareLayout(
        .layoutConstraints = layoutConstraints,
        .pointScaleFactor = layoutContext.pointScaleFactor},
       [&]() {
-        const auto& fabricUIManager =
-            contextContainer_->at<jni::global_ref<jobject>>("FabricUIManager");
+        auto fabricUIManager =
+            contextContainer_->at<jni::alias_ref<jobject>>("FabricUIManager");
         auto attributedStringMB = JReadableMapBuffer::createWithContents(
             toMapBuffer(attributedString));
         auto paragraphAttributesMB = JReadableMapBuffer::createWithContents(
@@ -364,8 +364,8 @@ TextLayoutManager::PreparedTextLayout TextLayoutManager::prepareLayout(
     javaReactTags->setRegion(
         0, static_cast<jsize>(reactTags.size()), reactTags.data());
 
-    const auto& fabricUIManager =
-        contextContainer_->at<jni::global_ref<jobject>>("FabricUIManager");
+    auto fabricUIManager =
+        contextContainer_->at<jni::alias_ref<jobject>>("FabricUIManager");
     return PreparedTextLayout{
         jni::make_global(reusePreparedLayoutWithNewReactTags(
             fabricUIManager, preparedText->get(), javaReactTags.get()))};
@@ -378,8 +378,8 @@ TextMeasurement TextLayoutManager::measurePreparedLayout(
     const PreparedTextLayout& preparedLayout,
     const TextLayoutContext& /*layoutContext*/,
     const LayoutConstraints& layoutConstraints) const {
-  const auto& fabricUIManager =
-      contextContainer_->at<jni::global_ref<jobject>>("FabricUIManager");
+  auto fabricUIManager =
+      contextContainer_->at<jni::alias_ref<jobject>>("FabricUIManager");
 
   static auto measurePreparedLayout =
       jni::findClassStatic("com/facebook/react/fabric/FabricUIManager")