Make ReactNativeConfig a JNI Class (#42247)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/42247

With this change I make `ReactNativeConfig` a JNI class loaded at Fabric Loading time.

This removes the default from `EmptyReactNativeConfig.java` and makes sure we do read the defaults from C++ `ReactNativeConfig.cpp` file.

Changelog:
[Internal] [Changed] - Make ReactNativeConfig a JNI Class

Reviewed By: motiz88

Differential Revision: D52696653

fbshipit-source-id: 99d5e37c65e0e59efcee2c857bb94194fb40d87d

packages/react-native/ReactAndroid/proguard-rules.pro

@@ -30,10 +30,16 @@
 -keepclassmembers class * {
     @com.facebook.proguard.annotations.DoNotStrip *;
 }
-
 -keep @com.facebook.proguard.annotations.DoNotStripAny class * {
     *;
 }
+-keep @com.facebook.jni.annotations.DoNotStrip class *
+-keepclassmembers class * {
+    @com.facebook.jni.annotations.DoNotStrip *;
+}
+-keep @com.facebook.jni.annotations.DoNotStripAny class * {
+    *;
+}
 
 -keepclassmembers @com.facebook.proguard.annotations.KeepGettersAndSetters class * {
   void set*(***);

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/fabric/EmptyReactNativeConfig.java

@@ -7,29 +7,34 @@
 
 package com.facebook.react.fabric;
 
+import androidx.annotation.NonNull;
+import com.facebook.jni.HybridData;
+import com.facebook.proguard.annotations.DoNotStripAny;
+
 /**
- * An empty {@link ReactNativeConfig} that is returning empty responses and false for all the
- * requested keys.
+ * An empty {@link ReactNativeConfig} that is backed by the C++ implementation where the defaults
+ * are store.
  */
+@DoNotStripAny
 public class EmptyReactNativeConfig implements ReactNativeConfig {
 
-  @Override
-  public boolean getBool(final String s) {
-    return false;
+  @NonNull private final HybridData mHybridData;
+
+  private static native HybridData initHybrid();
+
+  public EmptyReactNativeConfig() {
+    mHybridData = initHybrid();
   }
 
   @Override
-  public long getInt64(final String s) {
-    return 0;
-  }
+  public native boolean getBool(final String param);
 
   @Override
-  public String getString(final String s) {
-    return "";
-  }
+  public native long getInt64(final String param);
 
   @Override
-  public double getDouble(final String s) {
-    return 0;
-  }
+  public native String getString(final String param);
+
+  @Override
+  public native double getDouble(final String param);
 }

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

@@ -0,0 +1,47 @@
+/*
+ * 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 "JEmptyReactNativeConfig.h"
+#include <fbjni/fbjni.h>
+#include <react/config/ReactNativeConfig.h>
+
+namespace facebook::react {
+
+jni::local_ref<JEmptyReactNativeConfig::jhybriddata>
+JEmptyReactNativeConfig::initHybrid(jni::alias_ref<jclass>) {
+  return makeCxxInstance();
+}
+
+jboolean JEmptyReactNativeConfig::getBool(const jni::alias_ref<jstring> param) {
+  return reactNativeConfig_.getBool(param->toStdString());
+}
+
+jni::local_ref<jstring> JEmptyReactNativeConfig::getString(
+    const jni::alias_ref<jstring> param) {
+  return jni::make_jstring(reactNativeConfig_.getString(param->toStdString()));
+}
+
+jlong JEmptyReactNativeConfig::getInt64(const jni::alias_ref<jstring> param) {
+  return reactNativeConfig_.getInt64(param->toStdString());
+}
+
+jdouble JEmptyReactNativeConfig::getDouble(
+    const jni::alias_ref<jstring> param) {
+  return reactNativeConfig_.getDouble(param->toStdString());
+}
+
+void JEmptyReactNativeConfig::registerNatives() {
+  registerHybrid({
+      makeNativeMethod("initHybrid", JEmptyReactNativeConfig::initHybrid),
+      makeNativeMethod("getBool", JEmptyReactNativeConfig::getBool),
+      makeNativeMethod("getString", JEmptyReactNativeConfig::getString),
+      makeNativeMethod("getInt64", JEmptyReactNativeConfig::getInt64),
+      makeNativeMethod("getDouble", JEmptyReactNativeConfig::getDouble),
+  });
+}
+
+} // namespace facebook::react

packages/react-native/ReactAndroid/src/main/jni/react/fabric/JEmptyReactNativeConfig.h

@@ -0,0 +1,38 @@
+/*
+ * 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 <fbjni/fbjni.h>
+#include <react/config/ReactNativeConfig.h>
+#include <react/jni/ReadableNativeMap.h>
+#include <memory>
+
+namespace facebook::react {
+
+class JEmptyReactNativeConfig
+    : public jni::HybridClass<JEmptyReactNativeConfig> {
+ public:
+  constexpr static const char* const kJavaDescriptor =
+      "Lcom/facebook/react/fabric/EmptyReactNativeConfig;";
+
+  static void registerNatives();
+
+  jboolean getBool(const jni::alias_ref<jstring> param);
+
+  jni::local_ref<jstring> getString(const jni::alias_ref<jstring> param);
+
+  jlong getInt64(const jni::alias_ref<jstring> param);
+
+  jdouble getDouble(const jni::alias_ref<jstring> param);
+
+ private:
+  static jni::local_ref<jhybriddata> initHybrid(jni::alias_ref<jclass>);
+  const EmptyReactNativeConfig reactNativeConfig_ = EmptyReactNativeConfig();
+};
+
+} // namespace facebook::react

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

@@ -12,6 +12,7 @@
 #include "CoreComponentsRegistry.h"
 #include "EventBeatManager.h"
 #include "EventEmitterWrapper.h"
+#include "JEmptyReactNativeConfig.h"
 #include "StateWrapperImpl.h"
 #include "SurfaceHandlerBinding.h"
 
@@ -24,5 +25,6 @@ JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM* vm, void*) {
     facebook::react::ComponentFactory::registerNatives();
     facebook::react::CoreComponentsRegistry::registerNatives();
     facebook::react::SurfaceHandlerBinding::registerNatives();
+    facebook::react::JEmptyReactNativeConfig::registerNatives();
   });
 }

packages/react-native/ReactAndroid/src/main/jni/react/fabric/ReactNativeConfigHolder.h

@@ -15,7 +15,7 @@
 namespace facebook::react {
 
 /**
- * Implementation of ReactNativeConfig that wraps a FabricMobileConfig Java
+ * Implementation of ReactNativeConfig that wraps a ReactNativeConfig Java
  * object.
  */
 class ReactNativeConfigHolder : public ReactNativeConfig {

packages/react-native/ReactAndroid/src/test/java/com/facebook/react/runtime/ReactHostDelegateTest.kt

@@ -12,6 +12,7 @@ import com.facebook.react.bridge.JSBundleLoader
 import com.facebook.react.common.annotations.UnstableReactNativeAPI
 import com.facebook.react.defaults.DefaultReactHostDelegate
 import com.facebook.react.runtime.hermes.HermesInstance
+import com.facebook.testutils.fakes.FakeReactNativeConfig
 import com.facebook.testutils.shadows.ShadowSoLoader
 import org.assertj.core.api.Assertions.assertThat
 import org.junit.Test
@@ -36,12 +37,14 @@ class ReactHostDelegateTest {
         Mockito.mock(ReactPackageTurboModuleManagerDelegate.Builder::class.java)
     val hermesInstance: JSRuntimeFactory = Mockito.mock(HermesInstance::class.java)
     val jsMainModulePathMocked = "mockedJSMainModulePath"
+    val reactNativeConfig = FakeReactNativeConfig()
     val delegate =
         DefaultReactHostDelegate(
             jsMainModulePath = jsMainModulePathMocked,
             jsBundleLoader = jsBundleLoader,
             jsRuntimeFactory = hermesInstance,
-            turboModuleManagerDelegateBuilder = turboModuleManagerDelegateBuilderMock)
+            turboModuleManagerDelegateBuilder = turboModuleManagerDelegateBuilderMock,
+            reactNativeConfig = reactNativeConfig)
 
     assertThat(delegate.jsMainModulePath).isEqualTo(jsMainModulePathMocked)
   }

packages/react-native/ReactAndroid/src/test/java/com/facebook/testutils/fakes/FakeReactNativeConfig.kt

@@ -0,0 +1,21 @@
+/*
+ * 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.
+ */
+
+package com.facebook.testutils.fakes
+
+import com.facebook.react.fabric.ReactNativeConfig
+
+/** A fake [ReactNativeConfig] that returns default values for all methods without accessing JNI. */
+class FakeReactNativeConfig : ReactNativeConfig {
+  override fun getBool(param: String): Boolean = false
+
+  override fun getInt64(param: String): Long = 0L
+
+  override fun getString(param: String): String = ""
+
+  override fun getDouble(param: String): Double = 0.0
+}

packages/react-native/ReactCommon/react/config/ReactNativeConfig.h

@@ -27,7 +27,7 @@ class ReactNativeConfig {
 };
 
 /**
- * Empty configuration that will provide hardcoded values.
+ * Empty configuration that will provide hardcoded default values.
  */
 class EmptyReactNativeConfig : public ReactNativeConfig {
  public: