场景介绍

通过napi_wrap将ArkTS对象与Native的C++对象绑定，后续操作时再通过napi_unwrap将ArkTS对象绑定的C++对象取出，并对其进行操作。

使用示例

1. 接口声明、编译配置以及模块注册

   接口声明

// index.d.ts
export class MyObject {
   constructor(arg: number);
   plusOne: () => number;

   public get value();
   public set value(newVal: number);
}

编译配置

// CMakeLists.txt
# the minimum version of CMake.
cmake_minimum_required(VERSION 3.4.1)
project(object_wrap)

set(NATIVERENDER_ROOT_PATH ${CMAKE_CURRENT_SOURCE_DIR})

include_directories(${NATIVERENDER_ROOT_PATH}
                    ${NATIVERENDER_ROOT_PATH}/include)

add_definitions("-DLOG_DOMAIN=0x0000")
add_definitions("-DLOG_TAG=\"testTag\"")

add_library(object_wrap SHARED object_wrap.cpp)
target_link_libraries(object_wrap PUBLIC libace_napi.z.so libhilog_ndk.z.so)

模块注册

// object_wrap.cpp
class MyObject {
 public:
  static napi_value Init(napi_env env, napi_value exports);
  static void Destructor(napi_env env, void* nativeObject, void* finalize_hint);

 private:
  explicit MyObject(double value_ = 0);
  ~MyObject();

  static napi_value New(napi_env env, napi_callback_info info);
  static napi_value GetValue(napi_env env, napi_callback_info info);
  static napi_value SetValue(napi_env env, napi_callback_info info);
  static napi_value PlusOne(napi_env env, napi_callback_info info);

  double value_;
  napi_env env_;
  napi_ref wrapper_;
};

static thread_local napi_ref g_ref = nullptr;

MyObject::MyObject(double value)
    : value_(value), env_(nullptr), wrapper_(nullptr) {}

MyObject::~MyObject()
{
  napi_delete_reference(env_, wrapper_);
}

void MyObject::Destructor(napi_env env,
                          void* nativeObject,
                          [[maybe_unused]] void* finalize_hint)
{
  OH_LOG_INFO(LOG_APP, "MyObject::Destructor called");
  reinterpret_cast<MyObject*>(nativeObject)->~MyObject();
}

napi_value MyObject::Init(napi_env env, napi_value exports)
{
  napi_property_descriptor properties[] = {
      {"value", 0, 0, GetValue, SetValue, 0, napi_default, 0},
      { "plusOne", nullptr, PlusOne, nullptr, nullptr, nullptr, napi_default, nullptr }
  };

  napi_value cons;
  assert(napi_define_class(env, "MyObject", NAPI_AUTO_LENGTH, New, nullptr, 2,
                           properties, &cons) == napi_ok);

  assert(napi_create_reference(env, cons, 1, &g_ref) == napi_ok);
  assert(napi_set_named_property(env, exports, "MyObject", cons) == napi_ok);
  return exports;
}

EXTERN_C_START
static napi_value Init(napi_env env, napi_value exports)
{
    MyObject::Init(env, exports);
    return exports;
}
EXTERN_C_END

static napi_module nativeModule = {
    .nm_version = 1,
    .nm_flags = 0,
    .nm_filename = nullptr,
    .nm_register_func = Init,
    .nm_modname = "object_wrap",
    .nm_priv = nullptr,
    .reserved = { 0 },
};

extern "C" __attribute__((constructor)) void RegisterObjectWrapModule()
{
    napi_module_register(&nativeModule);
}

1. 在构造函数中绑定ArkJS与C++对象

napi_value MyObject::New(napi_env env, napi_callback_info info)
{
  OH_LOG_INFO(LOG_APP, "MyObject::New called");

  napi_value newTarget;
  assert(napi_get_new_target(env, info, &newTarget) == napi_ok);
  if (newTarget != nullptr) {
    // 使用`new MyObject(...)`调用方式
    size_t argc = 1;
    napi_value args[1];
    napi_value jsThis;
    assert(napi_get_cb_info(env, info, &argc, args, &jsThis, nullptr) == napi_ok);

    double value = 0.0;
    napi_valuetype valuetype;
    assert(napi_typeof(env, args[0], &valuetype) == napi_ok);
    if (valuetype != napi_undefined) {
      assert(napi_get_value_double(env, args[0], &value) == napi_ok);
    }

    MyObject* obj = new MyObject(value);

    obj->env_ = env;
    // 通过napi_wrap将ArkTS对象jsThis与C++对象obj绑定
    assert(napi_wrap(env,
                     jsThis,
                     reinterpret_cast<void*>(obj),
                     MyObject::Destructor,
                     nullptr,  // finalize_hint
                     &obj->wrapper_) == napi_ok);

    return jsThis;
  } else {
    // 使用`MyObject(...)`调用方式
    size_t argc = 1;
    napi_value args[1];
    assert(napi_get_cb_info(env, info, &argc, args, nullptr, nullptr) == napi_ok && argc == 1);

    napi_value cons;
    assert(napi_get_reference_value(env, g_ref, &cons) == napi_ok);
    napi_value instance;
    assert(napi_new_instance(env, cons, argc, args, &instance) == napi_ok);

    return instance;
  }
}

1. 将ArkTS对象之前绑定的C++对象取出，并对其进行操作

napi_value MyObject::GetValue(napi_env env, napi_callback_info info)
{
  OH_LOG_INFO(LOG_APP, "MyObject::GetValue called");

  napi_value jsThis;
  assert(napi_get_cb_info(env, info, nullptr, nullptr, &jsThis, nullptr) == napi_ok);

  MyObject* obj;
  // 通过napi_unwrap将jsThis之前绑定的C++对象取出，并对其进行操作
  assert(napi_unwrap(env, jsThis, reinterpret_cast<void**>(&obj)) == napi_ok);
  napi_value num;
  assert(napi_create_double(env, obj->value_, &num) == napi_ok);

  return num;
}

napi_value MyObject::SetValue(napi_env env, napi_callback_info info)
{
  OH_LOG_INFO(LOG_APP, "MyObject::SetValue called");

  size_t argc = 1;
  napi_value value;
  napi_value jsThis;

  assert(napi_get_cb_info(env, info, &argc, &value, &jsThis, nullptr) == napi_ok);

  MyObject* obj;
  // 通过napi_unwrap将jsThis之前绑定的C++对象取出，并对其进行操作
  assert(napi_unwrap(env, jsThis, reinterpret_cast<void**>(&obj)) == napi_ok);
  assert(napi_get_value_double(env, value, &obj->value_) == napi_ok);

  return nullptr;
}

napi_value MyObject::PlusOne(napi_env env, napi_callback_info info)
{
  OH_LOG_INFO(LOG_APP, "MyObject::PlusOne called");

  napi_value jsThis;
  assert(napi_get_cb_info(env, info, nullptr, nullptr, &jsThis, nullptr) == napi_ok);

  MyObject* obj;
  // 通过napi_unwrap将jsThis之前绑定的C++对象取出，并对其进行操作
  assert(napi_unwrap(env, jsThis, reinterpret_cast<void**>(&obj)) == napi_ok);
  obj->value_ += 1;
  napi_value num;
  assert(napi_create_double(env, obj->value_, &num) == napi_ok);

  return num;
}

1. ArkTS侧示例代码

import hilog from '@ohos.hilog';
import { MyObject } from 'libobject_wrap.so'

let object : MyObject = new MyObject(0);
object.value = 1023;
hilog.info(0x0000, 'testTag', 'MyObject value after set: %{public}d', object.value);
hilog.info(0x0000, 'testTag', 'MyObject plusOne: %{public}d', object.plusOne());