Add some temp code to test array buffers

RNTester/android/app/CMakeLists.txt

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.13.2)
+
+project(JSITest)
+
+add_subdirectory(${CMAKE_CURRENT_LIST_DIR}/../../../ReactCommon/jsi/jsi ${CMAKE_CURRENT_BINARY_DIR}/jsi)
+include_directories(
+    ${CMAKE_CURRENT_LIST_DIR}/../../../ReactCommon/jsi
+)
+
+add_library(JSITest SHARED src/main/cpp/JSITest.cpp)
+
+target_link_libraries(JSITest
+                      # link with these libraries:
+                      android
+                      log
+                      jsi)

RNTester/android/app/build.gradle

@@ -128,6 +128,12 @@ android {
         testBuildType System.getProperty('testBuildType', 'debug')  // This will later be used to control the test apk build type
         testInstrumentationRunner 'androidx.test.runner.AndroidJUnitRunner'
     }
+    externalNativeBuild {
+        cmake {
+            version '3.13.2+'
+            path 'CMakeLists.txt'
+        }
+    }
     signingConfigs {
         release {
             storeFile file(MYAPP_RELEASE_STORE_FILE)

RNTester/android/app/src/main/cpp/JSITest.cpp

@@ -0,0 +1,43 @@
+#include <jni.h>
+#include <jsi/jsi.h>
+#include <android/log.h>
+#include <sstream>
+
+using namespace facebook;
+
+namespace
+{
+    void log(const char *str)
+    {
+      __android_log_print(ANDROID_LOG_VERBOSE, "JSITest", "%s", str);
+    }
+}
+
+extern "C" JNIEXPORT void JNICALL Java_com_facebook_react_uiapp_JSITestModule_initialize(JNIEnv* env, jclass clazz, jlong jsiPtr)
+{
+  auto& jsiRuntime = *reinterpret_cast<facebook::jsi::Runtime*>(jsiPtr);
+
+  auto testFunction = jsi::Function::createFromHostFunction(jsiRuntime, jsi::PropNameID::forAscii(jsiRuntime, "testArrayBuffer"), 1, [](jsi::Runtime& runtime, const jsi::Value& thisValue, const jsi::Value* arguments, size_t count) -> jsi::Value
+  {
+      auto arrayBufferArg = arguments[0].asObject(runtime);
+      bool isArrayBuffer = arrayBufferArg.isArrayBuffer(runtime);
+      if (isArrayBuffer)
+      {
+        jsi::ArrayBuffer arrayBuffer = arrayBufferArg.getArrayBuffer(runtime);
+        uint8_t* arrayBufferData = arrayBuffer.data(runtime);
+        size_t arrayBufferSize = arrayBuffer.size(runtime);
+
+        for (int i = 0; i < arrayBufferSize; i++)
+        {
+          uint8_t element = arrayBufferData[i];
+          std::ostringstream message;
+          message << "Element at index " << i << ": " << std::to_string(element);
+          log(message.str().c_str());
+          arrayBufferData[i] = element * 2;
+        }
+      }
+
+      return nullptr;
+  });
+  jsiRuntime.global().setProperty(jsiRuntime, "testArrayBuffer", std::move(testFunction));
+}

RNTester/android/app/src/main/java/com/facebook/react/uiapp/JSITestPackage.java

@@ -0,0 +1,52 @@
+package com.facebook.react.uiapp;
+
+import androidx.annotation.NonNull;
+
+import com.facebook.react.ReactPackage;
+import com.facebook.react.bridge.NativeModule;
+import com.facebook.react.bridge.ReactApplicationContext;
+import com.facebook.react.bridge.ReactContextBaseJavaModule;
+import com.facebook.react.uimanager.ViewManager;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+class JSITestModule extends ReactContextBaseJavaModule {
+  static {
+    System.loadLibrary("JSITest");
+  }
+
+  private static native void initialize(long jsiPtr);
+
+  public JSITestModule(ReactApplicationContext reactContext) {
+    super(reactContext);
+  }
+
+  @NonNull
+  @Override
+  public String getName() {
+    return "JSITestModule";
+  }
+
+  @Override
+  public void initialize() {
+    super.initialize();
+
+    JSITestModule.initialize(this.getReactApplicationContext().getJavaScriptContextHolder().get());
+  }
+}
+
+class JSITestPackage implements ReactPackage {
+  @NonNull
+  @Override
+  public List<NativeModule> createNativeModules(@NonNull ReactApplicationContext reactContext) {
+    return Arrays.<NativeModule>asList(new JSITestModule(reactContext));
+  }
+
+  @NonNull
+  @Override
+  public List<ViewManager> createViewManagers(@NonNull ReactApplicationContext reactContext) {
+    return Collections.emptyList();
+  }
+}

RNTester/android/app/src/main/java/com/facebook/react/uiapp/RNTesterApplication.java

@@ -41,7 +41,7 @@ public boolean getUseDeveloperSupport() {
 
         @Override
         public List<ReactPackage> getPackages() {
-          return Arrays.<ReactPackage>asList(new MainReactPackage());
+          return Arrays.<ReactPackage>asList(new MainReactPackage(), new JSITestPackage());
         }
       };
 

RNTester/js/RNTesterApp.android.js

@@ -10,6 +10,13 @@
 
 'use strict';
 
+const testArray = new Uint8Array(2);
+testArray[0] = 42;
+testArray[1] = 101;
+testArrayBuffer(testArray.buffer);
+console.log(`Mutated element at index 0: ${testArray[0]}`);
+console.log(`Mutated element at index 1: ${testArray[1]}`);
+
 const RNTesterActions = require('./utils/RNTesterActions');
 const RNTesterExampleContainer = require('./components/RNTesterExampleContainer');
 const RNTesterExampleList = require('./components/RNTesterExampleList');

ReactCommon/jsi/jsi/jsi.h

@@ -773,7 +773,7 @@ class ArrayBuffer : public Object {
   ArrayBuffer(ArrayBuffer&&) = default;
   ArrayBuffer& operator=(ArrayBuffer&&) = default;
 
-  /// \return the size of the ArrayBuffer, according to its byteLength property.
+  /// \return the size of the ArrayBuffer, according to its  property.
   /// (C++ naming convention)
   size_t size(Runtime& runtime) const {
     return runtime.size(*this);