Remove useOptimizedViewRegistryOnAndroid feature flag (#57228)

Summary:
Pull Request resolved: #57228

The flag gated a more memory-efficient view registry implementation in `SurfaceMountingManager` (`MutableIntObjectMap` with a `ReadWriteLock` instead of `ConcurrentHashMap`). Removing the gate, keeping the optimized path, and inlining the helper methods that previously dispatched between the two implementations.

Changelog:
[Internal]

Reviewed By: mdvacca

Differential Revision: D108415790

fbshipit-source-id: b21cbb1923cf7d15e375df8d3c3c51d187eecee3

Author: javache

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/fabric/mounting/SurfaceMountingManager.kt

@@ -55,7 +55,6 @@ import com.facebook.systrace.Systrace
 import java.util.ArrayDeque
 import java.util.LinkedList
 import java.util.Queue
-import java.util.concurrent.ConcurrentHashMap
 import java.util.concurrent.locks.ReentrantReadWriteLock
 import kotlin.concurrent.Volatile
 import kotlin.concurrent.read
@@ -87,20 +86,9 @@ internal constructor(
   public var context: ThemedReactContext? = reactContext
     private set
 
-  private val tagToViewState: ConcurrentHashMap<Int, ViewState>?
-  private val optimizedTagToViewState: MutableIntObjectMap<ViewState>?
+  private val tagToViewState: MutableIntObjectMap<ViewState> = MutableIntObjectMap()
   private val registryLock = ReentrantReadWriteLock()
 
-  init {
-    if (ReactNativeFeatureFlags.useOptimizedViewRegistryOnAndroid()) {
-      tagToViewState = null
-      optimizedTagToViewState = MutableIntObjectMap()
-    } else {
-      tagToViewState = ConcurrentHashMap()
-      optimizedTagToViewState = null
-    }
-  }
-
   private val onViewAttachMountItems: Queue<MountItem> = ArrayDeque()
 
   // These are all non-null, until StopSurface is called
@@ -142,7 +130,9 @@ internal constructor(
       return
     }
 
-    registryPut(surfaceId, ViewState(surfaceId, rootView, rootViewManager, true))
+    registryLock.write {
+      tagToViewState[surfaceId] = ViewState(surfaceId, rootView, rootViewManager, true)
+    }
 
     val runnable: Runnable =
         object : GuardedRunnable(checkNotNull(context)) {
@@ -206,7 +196,7 @@ internal constructor(
     if (tagSetForStoppedSurface?.containsKey(tag) == true) {
       return true
     }
-    return registryContains(tag)
+    return registryLock.read { tagToViewState.containsKey(tag) }
   }
 
   @UiThread
@@ -252,42 +242,38 @@ internal constructor(
     // Reset all StateWrapper objects
     // Since this can happen on any thread, is it possible to race between StateWrapper destruction
     // and some accesses from View classes in the UI thread?
-    registryForEachValue { viewState ->
-      viewState.stateWrapper?.destroyState()
-      viewState.stateWrapper = null
+    registryLock.read {
+      tagToViewState.forEachValue { viewState ->
+        viewState.stateWrapper?.destroyState()
+        viewState.stateWrapper = null
 
-      viewState.eventEmitter?.destroy()
-      viewState.eventEmitter = null
+        viewState.eventEmitter?.destroy()
+        viewState.eventEmitter = null
+      }
     }
 
     val runnable = Runnable {
       if (ReactNativeFeatureFlags.enableViewRecycling()) {
         viewManagerRegistry?.onSurfaceStopped(surfaceId)
       }
 
-      if (optimizedTagToViewState != null) {
-        val viewStatesToDelete: ArrayList<ViewState>
-        registryLock.write {
-          val tagSetForStoppedSurface =
-              SparseArrayCompat<Any>().also { this.tagSetForStoppedSurface = it }
-          viewStatesToDelete = ArrayList(optimizedTagToViewState.size)
-          optimizedTagToViewState.forEach { key, value ->
-            tagSetForStoppedSurface[key] = this@SurfaceMountingManager
-            viewStatesToDelete.add(value)
-          }
-          optimizedTagToViewState.clear()
-        }
-        for (viewState in viewStatesToDelete) {
-          onViewStateDeleted(viewState)
+      // Using this as a placeholder value in the map. We're using SparseArrayCompat
+      // since it can efficiently represent the list of pending tags
+      val tagSetForStoppedSurface =
+          SparseArrayCompat<Any>().also { this.tagSetForStoppedSurface = it }
+
+      val viewStatesToDelete: ArrayList<ViewState>
+      registryLock.write {
+        viewStatesToDelete = ArrayList(tagToViewState.size)
+        tagToViewState.forEach { key, value ->
+          tagSetForStoppedSurface[key] = this@SurfaceMountingManager
+          viewStatesToDelete.add(value)
         }
-      } else {
-        val tagSetForStoppedSurface =
-            SparseArrayCompat<Any>().also { this.tagSetForStoppedSurface = it }
-        for ((key, value) in tagToViewState!!) {
-          tagSetForStoppedSurface[key] = this
-          onViewStateDeleted(value)
-        }
-        tagToViewState!!.clear()
+        tagToViewState.clear()
+      }
+      for (viewState in viewStatesToDelete) {
+        // We must call `onDropViewInstance` on all remaining Views
+        onViewStateDeleted(viewState)
       }
 
       // Evict all views from cache and memory
@@ -602,7 +588,7 @@ internal constructor(
             this.stateWrapper = stateWrapper
             this.eventEmitter = eventEmitterWrapper
           }
-      registryPut(reactTag, viewState)
+      registryLock.write { tagToViewState[reactTag] = viewState }
 
       if (isLayoutable) {
         @Suppress("UNCHECKED_CAST")
@@ -977,17 +963,9 @@ internal constructor(
 
     // TODO T62717437 - Use a flag to determine that these event emitters belong to virtual nodes
     // only.
-    val viewState: ViewState =
-        if (optimizedTagToViewState != null) {
-          registryLock.write { optimizedTagToViewState.getOrPut(reactTag) { ViewState(reactTag) } }
-        } else {
-          var vs = tagToViewState!![reactTag]
-          if (vs == null) {
-            vs = ViewState(reactTag)
-            tagToViewState!![reactTag] = vs
-          }
-          vs
-        }
+    val viewState: ViewState = registryLock.write {
+      tagToViewState.getOrPut(reactTag) { ViewState(reactTag) }
+    }
 
     val previousEventEmitterWrapper = viewState.eventEmitter
     synchronized(viewState) {
@@ -1096,7 +1074,7 @@ internal constructor(
       // To delete we simply remove the tag from the registry.
       // We want to rely on the correct set of MountInstructions being sent to the platform,
       // or StopSurface being called, so we do not handle deleting descendants of the View.
-      registryRemove(reactTag)
+      registryLock.write { tagToViewState.remove(reactTag) }
 
       onViewStateDeleted(viewState)
     }
@@ -1141,51 +1119,13 @@ internal constructor(
   }
 
   private fun getViewState(reactTag: Int): ViewState =
-      registryGet(reactTag)
+      getNullableViewState(reactTag)
           ?: throw RetryableMountingLayerException(
               "Unable to find viewState for tag $reactTag. Surface stopped: $isStopped"
           )
 
-  private fun getNullableViewState(reactTag: Int): ViewState? = registryGet(reactTag)
-
-  private fun registryGet(tag: Int): ViewState? {
-    return if (optimizedTagToViewState != null) {
-      registryLock.read { optimizedTagToViewState[tag] }
-    } else {
-      tagToViewState!![tag]
-    }
-  }
-
-  private fun registryPut(tag: Int, state: ViewState) {
-    if (optimizedTagToViewState != null) {
-      registryLock.write { optimizedTagToViewState[tag] = state }
-    } else {
-      tagToViewState!![tag] = state
-    }
-  }
-
-  private fun registryRemove(tag: Int) {
-    if (optimizedTagToViewState != null) {
-      registryLock.write { optimizedTagToViewState.remove(tag) }
-    } else {
-      tagToViewState!!.remove(tag)
-    }
-  }
-
-  private fun registryContains(tag: Int): Boolean {
-    return if (optimizedTagToViewState != null) {
-      registryLock.read { optimizedTagToViewState.containsKey(tag) }
-    } else {
-      tagToViewState!!.containsKey(tag)
-    }
-  }
-
-  private inline fun registryForEachValue(action: (ViewState) -> Unit) {
-    if (optimizedTagToViewState != null) {
-      registryLock.read { optimizedTagToViewState.forEachValue(action) }
-    } else {
-      tagToViewState!!.values.forEach(action)
-    }
+  private inline fun getNullableViewState(reactTag: Int): ViewState? = registryLock.read {
+    tagToViewState[reactTag]
   }
 
   /** Applies a bitmap as the background of the view with the given tag, if it exists. */
@@ -1197,16 +1137,18 @@ internal constructor(
 
   public fun printSurfaceState(): Unit {
     FLog.e(TAG, "Views created for surface $surfaceId:")
-    registryForEachValue { viewState ->
-      val viewManagerName = viewState.viewManager?.name
-      val view = viewState.view
-      val parent = if (view != null) view.parent as View? else null
-      val parentTag = parent?.id
+    registryLock.read {
+      tagToViewState.forEachValue { viewState ->
+        val viewManagerName = viewState.viewManager?.name
+        val view = viewState.view
+        val parent = if (view != null) view.parent as View? else null
+        val parentTag = parent?.id
 
-      FLog.e(
-          TAG,
-          "<$viewManagerName id=${viewState.reactTag} parentTag=$parentTag isRoot=${viewState.isRoot} />",
-      )
+        FLog.e(
+            TAG,
+            "<$viewManagerName id=${viewState.reactTag} parentTag=$parentTag isRoot=${viewState.isRoot} />",
+        )
+      }
     }
   }
 
@@ -1219,7 +1161,7 @@ internal constructor(
       @EventCategoryDef eventCategory: Int,
       eventTimestamp: Long,
   ) {
-    val viewState = registryGet(reactTag)
+    val viewState = getNullableViewState(reactTag)
     if (viewState == null) {
       FLog.i(TAG, "Unable to invoke event: %s for reactTag: %d", eventName, reactTag)
       return

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlags.kt

@@ -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<<17567d3adfba54ec2f888b50dae9efb8>>
+ * @generated SignedSource<<e5d648cb1649c713cac9ffaac905fc80>>
  */
 
 /**
@@ -498,12 +498,6 @@ public object ReactNativeFeatureFlags {
   @JvmStatic
   public fun useNestedScrollViewAndroid(): Boolean = accessor.useNestedScrollViewAndroid()
 
-  /**
-   * Use MutableIntObjectMap with ReadWriteLock instead of ConcurrentHashMap for the view registry in SurfaceMountingManager to reduce memory overhead and GC pressure.
-   */
-  @JvmStatic
-  public fun useOptimizedViewRegistryOnAndroid(): Boolean = accessor.useOptimizedViewRegistryOnAndroid()
-
   /**
    * Use shared animation backend in C++ Animated
    */

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsCxxAccessor.kt

@@ -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<<337b652caa9d443c8d83915e22210198>>
+ * @generated SignedSource<<5bf52aa57fc011858db9f632930bb8fb>>
  */
 
 /**
@@ -98,7 +98,6 @@ internal class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAcces
   private var useFabricInteropCache: Boolean? = null
   private var useNativeViewConfigsInBridgelessModeCache: Boolean? = null
   private var useNestedScrollViewAndroidCache: Boolean? = null
-  private var useOptimizedViewRegistryOnAndroidCache: Boolean? = null
   private var useSharedAnimatedBackendCache: Boolean? = null
   private var useTraitHiddenOnAndroidCache: Boolean? = null
   private var useTurboModuleInteropCache: Boolean? = null
@@ -809,15 +808,6 @@ internal class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAcces
     return cached
   }
 
-  override fun useOptimizedViewRegistryOnAndroid(): Boolean {
-    var cached = useOptimizedViewRegistryOnAndroidCache
-    if (cached == null) {
-      cached = ReactNativeFeatureFlagsCxxInterop.useOptimizedViewRegistryOnAndroid()
-      useOptimizedViewRegistryOnAndroidCache = cached
-    }
-    return cached
-  }
-
   override fun useSharedAnimatedBackend(): Boolean {
     var cached = useSharedAnimatedBackendCache
     if (cached == null) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsCxxInterop.kt

@@ -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<<b74d90991a4808bd1f3abfa75f3adcde>>
+ * @generated SignedSource<<4c03e1b03360e7703ffd1d7aa0afc277>>
  */
 
 /**
@@ -184,8 +184,6 @@ public object ReactNativeFeatureFlagsCxxInterop {
 
   @DoNotStrip @JvmStatic public external fun useNestedScrollViewAndroid(): Boolean
 
-  @DoNotStrip @JvmStatic public external fun useOptimizedViewRegistryOnAndroid(): Boolean
-
   @DoNotStrip @JvmStatic public external fun useSharedAnimatedBackend(): Boolean
 
   @DoNotStrip @JvmStatic public external fun useTraitHiddenOnAndroid(): Boolean

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsDefaults.kt

@@ -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<<efb2b99bb1697ec28c59e4d2244717ad>>
+ * @generated SignedSource<<98ed9f6f027f919cd31cd1e890750684>>
  */
 
 /**
@@ -179,8 +179,6 @@ public open class ReactNativeFeatureFlagsDefaults : ReactNativeFeatureFlagsProvi
 
   override fun useNestedScrollViewAndroid(): Boolean = false
 
-  override fun useOptimizedViewRegistryOnAndroid(): Boolean = false
-
   override fun useSharedAnimatedBackend(): Boolean = false
 
   override fun useTraitHiddenOnAndroid(): Boolean = false

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsLocalAccessor.kt

@@ -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<<164c9c2751f660ee098c12b8cf2c8b66>>
+ * @generated SignedSource<<d17ebed58238939efc1b3d4a2d7fd3c7>>
  */
 
 /**
@@ -102,7 +102,6 @@ internal class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcc
   private var useFabricInteropCache: Boolean? = null
   private var useNativeViewConfigsInBridgelessModeCache: Boolean? = null
   private var useNestedScrollViewAndroidCache: Boolean? = null
-  private var useOptimizedViewRegistryOnAndroidCache: Boolean? = null
   private var useSharedAnimatedBackendCache: Boolean? = null
   private var useTraitHiddenOnAndroidCache: Boolean? = null
   private var useTurboModuleInteropCache: Boolean? = null
@@ -891,16 +890,6 @@ internal class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcc
     return cached
   }
 
-  override fun useOptimizedViewRegistryOnAndroid(): Boolean {
-    var cached = useOptimizedViewRegistryOnAndroidCache
-    if (cached == null) {
-      cached = currentProvider.useOptimizedViewRegistryOnAndroid()
-      accessedFeatureFlags.add("useOptimizedViewRegistryOnAndroid")
-      useOptimizedViewRegistryOnAndroidCache = cached
-    }
-    return cached
-  }
-
   override fun useSharedAnimatedBackend(): Boolean {
     var cached = useSharedAnimatedBackendCache
     if (cached == null) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsProvider.kt

@@ -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<<b9cfc6790e36d7f7ff0ce9b87edca1e8>>
+ * @generated SignedSource<<4f18bde7c0680691cd6fceb63c41ad65>>
  */
 
 /**
@@ -179,8 +179,6 @@ public interface ReactNativeFeatureFlagsProvider {
 
   @DoNotStrip public fun useNestedScrollViewAndroid(): Boolean
 
-  @DoNotStrip public fun useOptimizedViewRegistryOnAndroid(): Boolean
-
   @DoNotStrip public fun useSharedAnimatedBackend(): Boolean
 
   @DoNotStrip public fun useTraitHiddenOnAndroid(): Boolean