harmony 鸿蒙自定义Native Transferable对象的多线程操作场景
自定义Native Transferable对象的多线程操作场景
在ArkTS应用开发中，有很多场景需要将ArkTS对象与Native对象进行绑定。ArkTS对象将数据写入Native对象，Native对象再将数据写入目的地。例如，将ArkTS对象中的数据写入C++数据库场景。
Native Transferable对象有两种模式：共享模式和转移模式。本示例将详细说明如何实现这两种模式。
- Native实现各项功能。
// napi_init.cpp
#include <mutex>
#include <unordered_set>
#include "napi/native_api.h"
#include <hilog/log.h>
class CustomNativeObject {
public:
CustomNativeObject() {}
~CustomNativeObject() = default;
static CustomNativeObject& GetInstance()
{
static CustomNativeObject instance;
return instance;
}
static napi_value GetAddress(napi_env env, napi_callback_info info)
{
napi_value thisVar = nullptr;
napi_get_cb_info(env, info, nullptr, nullptr, &thisVar, nullptr);
if (thisVar == nullptr) {
return nullptr;
}
void* object = nullptr;
napi_unwrap(env, thisVar, &object);
if (object == nullptr) {
return nullptr;
}
uint64_t addressVal = reinterpret_cast<uint64_t>(object);
napi_value address = nullptr;
napi_create_bigint_uint64(env, addressVal, &address);
return address;
}
// 获取数组大小
static napi_value GetSetSize(napi_env env, napi_callback_info info)
{
napi_value thisVar = nullptr;
napi_get_cb_info(env, info, nullptr, nullptr, &thisVar, nullptr);
if (thisVar == nullptr) {
return nullptr;
}
void* object = nullptr;
napi_unwrap(env, thisVar, &object);
if (object == nullptr) {
return nullptr;
}
CustomNativeObject* obj = static_cast<CustomNativeObject*>(object);
std::lock_guard<std::mutex> lock(obj->numberSetMutex_);
uint32_t setSize = reinterpret_cast<CustomNativeObject*>(object)->numberSet_.size();
napi_value napiSize = nullptr;
napi_create_uint32(env, setSize, &napiSize);
return napiSize;
}
// 往数组里插入元素
static napi_value Store(napi_env env, napi_callback_info info)
{
size_t argc = 1;
napi_value args[1] = {nullptr};
napi_value thisVar = nullptr;
napi_get_cb_info(env, info, &argc, args, &thisVar, nullptr);
if (argc != 1) {
napi_throw_error(env, nullptr, "Store args number must be one.");
return nullptr;
}
napi_valuetype type = napi_undefined;
napi_typeof(env, args[0], &type);
if (type != napi_number) {
napi_throw_error(env, nullptr, "Store args is not number.");
return nullptr;
}
if (thisVar == nullptr) {
return nullptr;
}
void* object = nullptr;
napi_unwrap(env, thisVar, &object);
if (object == nullptr) {
return nullptr;
}
uint32_t value = 0;
napi_get_value_uint32(env, args[0], &value);
CustomNativeObject* obj = static_cast<CustomNativeObject*>(object);
std::lock_guard<std::mutex> lock(obj->numberSetMutex_);
reinterpret_cast<CustomNativeObject *>(object)->numberSet_.insert(value);
return nullptr;
}
// 删除数组元素
static napi_value Erase(napi_env env, napi_callback_info info)
{
size_t argc = 1;
napi_value args[1] = {nullptr};
napi_value thisVar = nullptr;
napi_get_cb_info(env, info, &argc, args, &thisVar, nullptr);
if (argc != 1) {
napi_throw_error(env, nullptr, "Erase args number must be one.");
return nullptr;
}
napi_valuetype type = napi_undefined;
napi_typeof(env, args[0], &type);
if (type != napi_number) {
napi_throw_error(env, nullptr, "Erase args is not number.");
return nullptr;
}
if (thisVar == nullptr) {
return nullptr;
}
void* object = nullptr;
napi_unwrap(env, thisVar, &object);
if (object == nullptr) {
return nullptr;
}
uint32_t value = 0;
napi_get_value_uint32(env, args[0], &value);
CustomNativeObject* obj = static_cast<CustomNativeObject*>(object);
std::lock_guard<std::mutex> lock(obj->numberSetMutex_);
reinterpret_cast<CustomNativeObject *>(object)->numberSet_.erase(value);
return nullptr;
}
// 清空数组
static napi_value Clear(napi_env env, napi_callback_info info)
{
napi_value thisVar = nullptr;
napi_get_cb_info(env, info, nullptr, nullptr, &thisVar, nullptr);
if (thisVar == nullptr) {
return nullptr;
}
void* object = nullptr;
napi_unwrap(env, thisVar, &object);
if (object == nullptr) {
return nullptr;
}
CustomNativeObject* obj = static_cast<CustomNativeObject*>(object);
std::lock_guard<std::mutex> lock(obj->numberSetMutex_);
reinterpret_cast<CustomNativeObject *>(object)->numberSet_.clear();
return nullptr;
}
// 设置传输模式
static napi_value SetTransferDetached(napi_env env, napi_callback_info info)
{
size_t argc = 1;
napi_value args[1];
napi_value thisVar;
napi_get_cb_info(env, info, &argc, args, &thisVar, nullptr);
if (argc != 1) {
napi_throw_error(env, nullptr, "SetTransferDetached args number must be one.");
return nullptr;
}
if (thisVar == nullptr) {
return nullptr;
}
napi_valuetype type = napi_undefined;
napi_typeof(env, args[0], &type);
if (type != napi_boolean) {
napi_throw_error(env, nullptr, "SetTransferDetached args is not boolean.");
return nullptr;
}
bool isDetached;
napi_get_value_bool(env, args[0], &isDetached);
void* object = nullptr;
napi_unwrap(env, thisVar, &object);
if (object == nullptr) {
return nullptr;
}
CustomNativeObject* obj = static_cast<CustomNativeObject*>(object);
std::lock_guard<std::mutex> lock(obj->numberSetMutex_);
obj->isDetached_ = isDetached;
return nullptr;
}
bool isDetached_ = false;
private:
CustomNativeObject(const CustomNativeObject &) = delete;
CustomNativeObject &operator=(const CustomNativeObject &) = delete;
std::unordered_set<uint32_t> numberSet_{};
std::mutex numberSetMutex_{};
};
void FinializeCallback(napi_env env, void *data, void *hint)
{
return;
}
// 解绑回调，在序列化时调用，可在对象解绑时执行一些清理操作
void* DetachCallback(napi_env env, void *value, void *hint)
{
if (hint == nullptr) {
return value;
}
napi_value jsObject = nullptr;
napi_get_reference_value(env, reinterpret_cast<napi_ref>(hint), &jsObject);
void* object = nullptr;
if (static_cast<CustomNativeObject*>(value)->isDetached_) {
napi_remove_wrap(env, jsObject, &object);
}
return value;
}
// 绑定回调，在反序列化时调用
napi_value AttachCallback(napi_env env, void* value, void* hint)
{
napi_value object = nullptr;
napi_create_object(env, &object);
napi_property_descriptor desc[] = {
{"getAddress", nullptr, CustomNativeObject::GetAddress, nullptr, nullptr, nullptr, napi_default, nullptr},
{"getSetSize", nullptr, CustomNativeObject::GetSetSize, nullptr, nullptr, nullptr, napi_default, nullptr},
{"store", nullptr, CustomNativeObject::Store, nullptr, nullptr, nullptr, napi_default, nullptr},
{"erase", nullptr, CustomNativeObject::Erase, nullptr, nullptr, nullptr, napi_default, nullptr},
{"clear", nullptr, CustomNativeObject::Clear, nullptr, nullptr, nullptr, napi_default, nullptr}};
napi_define_properties(env, object, sizeof(desc) / sizeof(desc[0]), desc);
// 将JS对象object和native对象value生命周期进行绑定
napi_wrap(env, object, value, FinializeCallback, nullptr, nullptr);
// JS对象携带native信息
napi_coerce_to_native_binding_object(env, object, DetachCallback, AttachCallback, value, nullptr);
return object;
}
EXTERN_C_START
static napi_value Init(napi_env env, napi_value exports)
{
napi_property_descriptor desc[] = {
{"getAddress", nullptr, CustomNativeObject::GetAddress, nullptr, nullptr, nullptr, napi_default, nullptr},
{"getSetSize", nullptr, CustomNativeObject::GetSetSize, nullptr, nullptr, nullptr, napi_default, nullptr},
{"store", nullptr, CustomNativeObject::Store, nullptr, nullptr, nullptr, napi_default, nullptr},
{"erase", nullptr, CustomNativeObject::Erase, nullptr, nullptr, nullptr, napi_default, nullptr},
{"clear", nullptr, CustomNativeObject::Clear, nullptr, nullptr, nullptr, napi_default, nullptr},
{"setTransferDetached", nullptr, CustomNativeObject::SetTransferDetached, nullptr, nullptr, nullptr, napi_default, nullptr}};
napi_define_properties(env, exports, sizeof(desc) / sizeof(desc[0]), desc);
auto &object = CustomNativeObject::GetInstance();
napi_wrap(env, exports, reinterpret_cast<void*>(&object), FinializeCallback, nullptr, nullptr);
napi_ref exportsRef;
napi_create_reference(env, exports, 1, &exportsRef);
napi_coerce_to_native_binding_object(env, exports, DetachCallback, AttachCallback, reinterpret_cast<void*>(&object), exportsRef);
return exports;
}
EXTERN_C_END
static napi_module demoModule = {
.nm_version = 1,
.nm_flags = 0,
.nm_filename = nullptr,
.nm_register_func = Init,
.nm_modname = "entry",
.nm_priv = ((void*)0),
.reserved = { 0 },
};
extern "C" __attribute__((constructor)) void RegisterEntryModule(void)
{
napi_module_register(&demoModule);
}
- 在ArkTS中声明接口。
// Index.d.ts
export const getAddress: () => number;
export const getSetSize: () => number;
export const store: (a: number) => void;
export const erase: (a: number) => void;
export const clear: () => void;
export const setTransferDetached: (b : boolean) => number;
- ArkTS对象调用Native侧实现的各项功能。
在转移模式下，跨线程传递后，原来的ArkTS对象与Native对象解绑，因此不能继续访问。示例如下：
import testNapi from 'libentry.so';
import { taskpool } from '@kit.ArkTS';
@Concurrent
function getAddress() {
let address: number = testNapi.getAddress();
console.info("taskpool:: address is " + address);
}
@Concurrent
function store(a:number, b:number, c:number) {
let size:number = testNapi.getSetSize();
console.info("set size is " + size + " before store");
testNapi.store(a);
testNapi.store(b);
testNapi.store(c);
size = testNapi.getSetSize();
console.info("set size is " + size + " after store");
}
@Concurrent
function erase(a:number) {
let size:number = testNapi.getSetSize();
console.info("set size is " + size + " before erase");
testNapi.erase(a);
size = testNapi.getSetSize();
console.info("set size is " + size + " after erase");
}
@Concurrent
function clear() {
let size:number = testNapi.getSetSize();
console.info("set size is " + size + " before clear");
testNapi.clear();
size = testNapi.getSetSize();
console.info("set size is " + size + " after clear");
}
// 转移模式
async function test(): Promise<void> {
// setTransferDetached 设置为true，表示传输方式为转移模式
testNapi.setTransferDetached(true);
let address:number = testNapi.getAddress();
console.info("host thread address is " + address);
let task1 = new taskpool.Task(getAddress, testNapi);
await taskpool.execute(task1);
let task2 = new taskpool.Task(store, 1, 2, 3);
await taskpool.execute(task2);
let task3 = new taskpool.Task(store, 4, 5, 6);
await taskpool.execute(task3);
// 由于已经设置了转移模式，且testNapi已跨线程传递，所以主线程无法继续访问到Native对象的值
let size:number = testNapi.getSetSize();
// 输出的日志为“host thread size is undefined”
console.info("host thread size is " + size);
let task4 = new taskpool.Task(erase, 3);
await taskpool.execute(task4);
let task5 = new taskpool.Task(erase, 5);
await taskpool.execute(task5);
let task6 = new taskpool.Task(clear);
await taskpool.execute(task6);
}
@Entry
@Component
struct Index {
@State message: string = 'Hello World';
build() {
Row() {
Column() {
Text(this.message)
.fontSize($r('app.float.page_text_font_size'))
.fontWeight(FontWeight.Bold)
.onClick(() => {
test();
})
}
.width('100%')
}
.height('100%')
}
}
在共享模式下，跨线程传递后，原来的ArkTS对象还可以继续访问Native对象。示例如下：
import testNapi from 'libentry.so';
import { taskpool } from '@kit.ArkTS';
@Concurrent
function getAddress() {
let address: number = testNapi.getAddress();
console.info("taskpool:: address is " + address);
}
@Concurrent
function store(a:number, b:number, c:number) {
let size:number = testNapi.getSetSize();
console.info("set size is " + size + " before store");
testNapi.store(a);
testNapi.store(b);
testNapi.store(c);
size = testNapi.getSetSize();
console.info("set size is " + size + " after store");
}
@Concurrent
function erase(a:number) {
let size:number = testNapi.getSetSize();
console.info("set size is " + size + " before erase");
testNapi.erase(a);
size = testNapi.getSetSize();
console.info("set size is " + size + " after erase");
}
@Concurrent
function clear() {
let size:number = testNapi.getSetSize();
console.info("set size is " + size + " before clear");
testNapi.clear();
size = testNapi.getSetSize();
console.info("set size is " + size + " after clear");
}
// 共享模式
async function test(): Promise<void> {
let address:number = testNapi.getAddress();
console.info("host thread address is " + address);
let task1 = new taskpool.Task(getAddress, testNapi);
await taskpool.execute(task1);
let task2 = new taskpool.Task(store, 1, 2, 3);
await taskpool.execute(task2);
let task3 = new taskpool.Task(store, 4, 5, 6);
await taskpool.execute(task3);
// 由于默认的传输模式为共享模式，testNapi跨线程传递后，主线程可以继续访问Native对象的值
let size:number = testNapi.getSetSize();
// 输出的日志为“host thread size is 6
console.info("host thread size is " + size);
let task4 = new taskpool.Task(erase, 3);
await taskpool.execute(task4);
let task5 = new taskpool.Task(erase, 5);
await taskpool.execute(task5);
let task6 = new taskpool.Task(clear);
await taskpool.execute(task6);
}
@Entry
@Component
struct Index {
@State message: string = 'Hello World';
build() {
Row() {
Column() {
Text(this.message)
.fontSize($r('app.float.page_text_font_size'))
.fontWeight(FontWeight.Bold)
.onClick(() => {
test();
})
}
.width('100%')
}
.height('100%')
}
}
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