Support C++ construction of WritableNativeMap (#59618)

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/WritableNativeMap.kt

@@ -15,9 +15,15 @@ import com.facebook.proguard.annotations.DoNotStrip
  * to stub out creating this class in a test. TODO(5815532): Check if consumed on read
  */
 @DoNotStrip
-public class WritableNativeMap : ReadableNativeMap(), WritableMap {
+public class WritableNativeMap @DoNotStrip private constructor(initializeNative: Boolean) :
+    ReadableNativeMap(), WritableMap {
+  /** Creates an empty writable map backed by native memory. */
+  public constructor() : this(true)
+
   init {
-    initHybrid()
+    if (initializeNative) {
+      initHybrid()
+    }
   }
 
   external override fun putBoolean(key: String, value: Boolean)

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

@@ -10,6 +10,7 @@
 #include <react/fabric/FabricUIManagerBinding.h>
 #include <react/featureflags/ReactNativeFeatureFlags.h>
 #include <react/featureflags/ReactNativeFeatureFlagsDefaults.h>
+#include <react/jni/WritableNativeMap.h>
 #include <react/renderer/animationbackend/AnimatedProps.h>
 #include <react/renderer/componentregistry/ComponentDescriptorProviderRegistry.h>
 #include <react/renderer/components/root/RootShadowNode.h>
@@ -62,6 +63,17 @@ class FabricMountingManagerTestHelper::DeleteRecorder
 
 namespace {
 
+jni::local_ref<WritableNativeMap::jhybridobject> createWritableNativeMapFromCxx(
+    jni::alias_ref<jclass> /*unused*/,
+    jboolean withContents) {
+  if (withContents == JNI_FALSE) {
+    return WritableNativeMap::newObjectCxxArgs();
+  }
+  folly::dynamic payload = folly::dynamic::object("value", 42)(
+      "nested", folly::dynamic::object("enabled", true));
+  return WritableNativeMap::newObjectCxxArgs(std::move(payload));
+}
+
 ShadowView makeShadowView(jint surfaceId, jint tag) {
   ShadowView sv{};
   sv.componentName = "View";
@@ -402,6 +414,8 @@ FabricMountingManagerTestHelper::pulledDeleteTags() {
 
 void FabricMountingManagerTestHelper::registerNatives() {
   registerHybrid({
+      makeNativeMethod(
+          "createWritableNativeMapFromCxx", createWritableNativeMapFromCxx),
       makeNativeMethod(
           "initHybrid", FabricMountingManagerTestHelper::initHybrid),
       makeNativeMethod(

packages/react-native/ReactAndroid/src/main/jni/react/jni/TouchesHelper.cpp

@@ -8,8 +8,8 @@
 #include "TouchesHelper.h"
 
 #include <stdexcept>
+#include <utility>
 
-#include "WritableNativeArray.h"
 #include "WritableNativeMap.h"
 
 using namespace facebook::jni;
@@ -72,25 +72,11 @@ local_ref<WritableNativeMap::jhybridobject> createTouchPayload(
     }
   }
 
-  auto jPayload = WritableNativeMap::newObjectJavaArgs();
-  auto* payload = jPayload->cthis();
-  // NOLINTBEGIN(cppcoreguidelines-pro-bounds-pointer-arithmetic)
-  const double* fields = values.get() + eventPointer * kPointerFields;
-  payload->putDouble("pageX", fields[kPageXIndex]);
-  payload->putDouble("pageY", fields[kPageYIndex]);
-  payload->putDouble("locationX", fields[kLocationXIndex]);
-  payload->putDouble("locationY", fields[kLocationYIndex]);
-  payload->putInt(
-      "targetSurface", static_cast<int>(fields[kTargetSurfaceIndex]));
-  payload->putInt("target", static_cast<int>(fields[kTargetIndex]));
-  payload->putDouble("timestamp", fields[kTimestampIndex]);
-  payload->putDouble("identifier", fields[kIdentifierIndex]);
-  // NOLINTEND(cppcoreguidelines-pro-bounds-pointer-arithmetic)
-  WritableNativeArray changedTouchesArray(std::move(changedTouches));
-  payload->putNativeArray("changedTouches", &changedTouchesArray);
-  WritableNativeArray touchesArray(std::move(touches));
-  payload->putNativeArray("touches", &touchesArray);
-  return jPayload;
+  // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)
+  auto payload = createTouch(values.get() + eventPointer * kPointerFields);
+  payload.insert("changedTouches", std::move(changedTouches));
+  payload.insert("touches", std::move(touches));
+  return WritableNativeMap::newObjectCxxArgs(std::move(payload));
 }
 
 } // namespace

packages/react-native/ReactAndroid/src/main/jni/react/jni/WritableNativeMap.cpp

@@ -7,6 +7,8 @@
 
 #include "WritableNativeMap.h"
 
+#include <utility>
+
 using namespace facebook::jni;
 
 namespace facebook::react {
@@ -20,6 +22,13 @@ WritableNativeMap::WritableNativeMap(folly::dynamic&& val)
   }
 }
 
+local_ref<WritableNativeMap::JavaPart> WritableNativeMap::newObjectCxxArgs(
+    folly::dynamic&& val) {
+  auto map = newObjectJavaArgs(false);
+  setCxxInstance(map, std::move(val));
+  return map;
+}
+
 void WritableNativeMap::initHybrid(alias_ref<jhybridobject> jobj) {
   setCxxInstance(jobj);
 }

packages/react-native/ReactAndroid/src/main/jni/react/jni/WritableNativeMap.h

@@ -26,6 +26,9 @@ struct WritableNativeMap : jni::HybridClass<WritableNativeMap, ReadableNativeMap
   WritableNativeMap();
   WritableNativeMap(folly::dynamic &&val);
 
+  /** Creates a Java map without invoking initHybrid before installing its C++ contents. */
+  static jni::local_ref<JavaPart> newObjectCxxArgs(folly::dynamic &&val = folly::dynamic::object());
+
   static void initHybrid(jni::alias_ref<jhybridobject> jobj);
 
   void putNull(std::string key);

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

@@ -8,6 +8,10 @@
 package com.facebook.react.fabric
 
 import android.graphics.Rect
+import android.os.ParcelFileDescriptor
+import android.os.Process
+import android.os.SystemClock
+import android.util.Log
 import android.view.View
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import androidx.test.platform.app.InstrumentationRegistry
@@ -35,6 +39,7 @@ import com.facebook.react.uimanager.events.BatchEventDispatchedListener
 import com.facebook.react.views.view.ReactViewGroup
 import com.facebook.react.views.view.ReactViewManager
 import com.facebook.soloader.SoLoader
+import java.util.UUID
 import org.assertj.core.api.Assertions.assertThat
 import org.assertj.core.api.Assertions.within
 import org.junit.After
@@ -134,6 +139,55 @@ class FabricMountingManagerInstrumentationTest {
     assertThat(smm.getView(42)).isNotNull()
   }
 
+  @Test
+  fun writableNativeMap_createdInCxx_preservesContentsAndRemainsWritable() {
+    val map = createWritableNativeMapFromCxx(true)
+
+    map.putInt("added", 7)
+    map.putString("label", "writable")
+    assertThat(map.getInt("value")).isEqualTo(42)
+    assertThat(map.getMap("nested")?.getBoolean("enabled")).isTrue()
+    assertThat(map.getInt("added")).isEqualTo(7)
+    assertThat(map.getString("label")).isEqualTo("writable")
+  }
+
+  @Test
+  fun writableNativeMap_createdInCxxWithoutContents_isEmptyAndWritable() {
+    val map = createWritableNativeMapFromCxx(false)
+
+    assertThat(map.toString()).isEqualTo("{}")
+    map.putInt("value", 42)
+    assertThat(map.getInt("value")).isEqualTo(42)
+  }
+
+  private fun createWritableNativeMapFromCxx(withContents: Boolean): WritableNativeMap {
+    val token = UUID.randomUUID().toString()
+    val startMarker = "WritableNativeMap start $token"
+    val endMarker = "WritableNativeMap end $token"
+    Log.i("WritableNativeMapTest", startMarker)
+    val map = FabricMountingManagerTestHelper.createWritableNativeMapFromCxx(withContents)
+    Log.i("WritableNativeMapTest", endMarker)
+
+    val deadline = SystemClock.elapsedRealtime() + 2_000
+    do {
+      val descriptor =
+          InstrumentationRegistry.getInstrumentation()
+              .uiAutomation
+              .executeShellCommand("logcat -d -b main --pid=${Process.myPid()}")
+      val logs =
+          ParcelFileDescriptor.AutoCloseInputStream(descriptor).bufferedReader().use {
+            it.readText()
+          }
+      if (logs.contains(endMarker)) {
+        assertThat(logs).contains(startMarker)
+        assertThat(logs.substringAfter(startMarker).substringBefore(endMarker))
+            .doesNotContain("Attempt to set C++ native pointer twice")
+        return map
+      }
+    } while (SystemClock.elapsedRealtime() < deadline)
+    throw AssertionError("WritableNativeMap log markers did not arrive")
+  }
+
   @Test
   fun writableNativeMap_mutationAfterImportingValues_preservesCachedPointers() {
     val map = WritableNativeMap()
@@ -252,7 +306,7 @@ class FabricMountingManagerInstrumentationTest {
   }
 
   private fun mountPaddedView(
-      fixTextLayoutOnPixelDensityChange: Boolean
+      fixTextLayoutOnPixelDensityChange: Boolean,
   ): Pair<FabricMountingManagerTestHelper, ReactViewGroup> {
     val fabricUIManager = createFabricUIManager(listOf(PaddingViewManager()))
     val helper = FabricMountingManagerTestHelper.create(fabricUIManager)
@@ -281,7 +335,7 @@ class FabricMountingManagerInstrumentationTest {
     ReactNativeFeatureFlagsCxxInterop.dangerouslyForceOverride(
         object : ReactNativeFeatureFlagsDefaults() {
           override fun enableMountingCoordinatorPullModelAndroid(): Boolean = true
-        }
+        },
     )
   }
 
@@ -501,7 +555,7 @@ class FabricMountingManagerInstrumentationTest {
           override fun enablePropsUpdateReconciliationAndroid(): Boolean = pullModel
 
           override fun enablePreallocatedPropsDiffOnInsertAndroid(): Boolean = pullModel
-        }
+        },
     )
   }
 

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

@@ -8,9 +8,11 @@
 package com.facebook.react.fabric
 
 import com.facebook.jni.HybridClassBase
+import com.facebook.proguard.annotations.DoNotStrip
 import com.facebook.react.bridge.NativeMap
 import com.facebook.react.bridge.RuntimeExecutor
 import com.facebook.react.bridge.RuntimeScheduler
+import com.facebook.react.bridge.WritableNativeMap
 import com.facebook.soloader.SoLoader
 
 /**
@@ -90,6 +92,10 @@ private constructor(fabricUIManager: FabricUIManager) : HybridClassBase() {
       SoLoader.loadLibrary("fabricjni_test_helper")
     }
 
+    @DoNotStrip
+    @JvmStatic
+    external fun createWritableNativeMapFromCxx(withContents: Boolean): WritableNativeMap
+
     @JvmStatic
     fun create(fabricUIManager: FabricUIManager): FabricMountingManagerTestHelper {
       return FabricMountingManagerTestHelper(fabricUIManager)

scripts/cxx-api/api-snapshots/ReactAndroidDebugCxx.api

@@ -3756,6 +3756,7 @@ struct facebook::react::WritableNativeMap : public jni::HybridClass<facebook::re
   public WritableNativeMap(folly::dynamic&& val);
   public friend HybridBase;
   public static constexpr auto kJavaDescriptor;
+  public static jni::local_ref<JavaPart> newObjectCxxArgs(folly::dynamic&& val = folly::dynamic::object());
   public static void initHybrid(jni::alias_ref<jhybridobject> jobj);
   public static void registerNatives();
   public void mergeNativeMap(facebook::react::ReadableNativeMap* other);

scripts/cxx-api/api-snapshots/ReactAndroidFrameworksCxx.api

@@ -6806,6 +6806,7 @@ struct facebook::react::WritableNativeMap : public jni::HybridClass<facebook::re
   public WritableNativeMap(folly::dynamic&& val);
   public friend HybridBase;
   public static constexpr auto kJavaDescriptor;
+  public static jni::local_ref<JavaPart> newObjectCxxArgs(folly::dynamic&& val = folly::dynamic::object());
   public static void initHybrid(jni::alias_ref<jhybridobject> jobj);
   public static void registerNatives();
   public void mergeNativeMap(facebook::react::ReadableNativeMap* other);

scripts/cxx-api/api-snapshots/ReactAndroidNewarchCxx.api

@@ -3749,6 +3749,7 @@ struct facebook::react::WritableNativeMap : public jni::HybridClass<facebook::re
   public WritableNativeMap(folly::dynamic&& val);
   public friend HybridBase;
   public static constexpr auto kJavaDescriptor;
+  public static jni::local_ref<JavaPart> newObjectCxxArgs(folly::dynamic&& val = folly::dynamic::object());
   public static void initHybrid(jni::alias_ref<jhybridobject> jobj);
   public static void registerNatives();
   public void mergeNativeMap(facebook::react::ReadableNativeMap* other);

scripts/cxx-api/api-snapshots/ReactAndroidReleaseCxx.api

@@ -3749,6 +3749,7 @@ struct facebook::react::WritableNativeMap : public jni::HybridClass<facebook::re
   public WritableNativeMap(folly::dynamic&& val);
   public friend HybridBase;
   public static constexpr auto kJavaDescriptor;
+  public static jni::local_ref<JavaPart> newObjectCxxArgs(folly::dynamic&& val = folly::dynamic::object());
   public static void initHybrid(jni::alias_ref<jhybridobject> jobj);
   public static void registerNatives();
   public void mergeNativeMap(facebook::react::ReadableNativeMap* other);