网络 harmonyos 华为移动开发 IT互联网 OpenHarmony 串口服务访问

项目介绍

本文档是在eTS项目hap包中实现串口访问的使用说明，通过JS接口开放给上层应用使用。

一、开发环境准备

安装OpenHarmony SDK

1. 在DevEco Studio菜单栏选择Tools->SDK Manager

2. OpenHarmony SDK选项中选择配备API版本进行安装

二、创建eTS项目

创建支持Native C++的eTS项目

三、NAPI库相关

生成串口NAPI库

1. 添加文件src/main/cpp/types/libserialhelper/serialhelper.d.ts

* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

* http://www.apache.org/licenses/LICENSE-2.0

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

import {AsyncCallback, Callback} from "basic";

declare namespace serialHelper {

/**

* Open serial port.

* @param dev Indicates the serial port dev.

function openSerial(dev:string, callback: AsyncCallback): void;

function openSerial(dev:string): Promise;

/**

* Close serial port.

* @param dev Indicates the serial port dev.

function closeSerial(dev:string, callback: AsyncCallback): void;

function closeSerial(dev:string): Promise;

}

export default serialHelper;

2. 添加文件src/main/cpp/types/libserialhelper/package.json

{

"name": "libserialhelper.so",

"types": "./serialhelper.d.ts"

}

3. 根据serialhelper.d.ts文件生成对应的c++源码

方式一：手动编写src/main/cpp/serial_helper.cpp

struct AsyncCallInfo{

napi_env env = nullptr;

napi_ref callbackRef = nullptr;

napi_deferred deferred = nullptr;

napi_async_work work = nullptr;

void *data = nullptr;

};

static void AsyncCallFinish(AsyncCallInfo* asyncCallInfo, int32_t result, napi_value *asyncResult)

{

if (asyncCallInfo->deferred) {

if (result == 0) {

napi_resolve_deferred(asyncCallInfo->env, asyncCallInfo->deferred,

asyncResult[1]==nullptr?asyncResult[0]:asyncResult[1]);

} else {

napi_reject_deferred(asyncCallInfo->env, asyncCallInfo->deferred, asyncResult[0]);

}

} else {

napi_value callback = nullptr;

napi_get_reference_value(asyncCallInfo->env, asyncCallInfo->callbackRef, &callback);

napi_call_function(asyncCallInfo->env, nullptr, callback, CALLBACK_ARGV_CNT, asyncResult, nullptr);

napi_delete_reference(asyncCallInfo->env, asyncCallInfo->callbackRef);

}

static napi_value Call_OpenSerial(napi_env env, napi_callback_info info)

{

size_t argc = 0;

napi_value args[DEFAULT_ARG_COUNT] = {0};

napi_get_cb_info(env, info, &argc, args , nullptr, nullptr);

...

napi_value resourceName = nullptr;

napi_create_string_utf8(env, "x_napi_tool", NAPI_AUTO_LENGTH, &resourceName);

napi_create_async_work(env, nullptr, resourceName,

[](napi_env env, void* data) {

AsyncCallInfo* asyncCallInfo = (AsyncCallInfo*)data;

OpenSerialValue* openValue = (OpenSerialValue*)asyncCallInfo->data;

//openValue->out = SerialClient::GetInstance()->OpenSerial(openValue->dev);

[](napi_env env, napi_status status, void* data) {

AsyncCallInfo* asyncCallInfo = (AsyncCallInfo*)data;

OpenSerialValue* openValue = (OpenSerialValue*)asyncCallInfo->data;

napi_value asyncResult[CALLBACK_ARGV_CNT]={nullptr, nullptr};

napi_create_int32(env, openValue->out, &asyncResult[0]);

AsyncCallFinish(asyncCallInfo, openValue->out,asyncResult);

napi_delete_async_work(env, asyncCallInfo->work);

delete openValue;

delete asyncCallInfo;

(void*)asyncCallInfo, &asyncCallInfo->work);

napi_queue_async_work(env, asyncCallInfo->work);

return retValue;

}

方式二：使用NAPI框架生成工具生成工具链接

1）将serialhelper.d.ts、basic.d.ts复制到同一目录中，创建out目录

2）执行./napi_generator-linux -f serialhelper.d.ts -o out

3）将生成的源码文件复制到src/main/cpp

4. make文件：src/main/cpp/CMakeList.txt

# the minimum version of CMake.

cmake_minimum_required(VERSION 3.4.1)

project(XComponent)

set(NATIVERENDER_ROOT_PATH ${CMAKE_CURRENT_SOURCE_DIR})

include_directories(${NATIVERENDER_ROOT_PATH})

add_library(serialhelper SHARED serial_helper.cpp)

target_link_libraries(serialhelper PUBLIC libace_napi.z.so libc++.a)

5. 添加项目依赖

entry/package.json

"devDependencies": {

"@types/libserialhelper.so": "file:./src/main/cpp/types/libserialhelper"

}

entry/package-lock.json

"dependencies": {

"@types/libserialhelper.so": {

"version": "file:src/main/cpp/types/libserialhelper",

"dev": true

}

6. 编译生成

修改编译项entry/build-profile.json5：

"buildOption": {

"externalNativeOptions": {

"path": "./src/main/cpp/CMakeLists.txt",

"arguments": "-v -DOHOS_STL=c++_shared",

"abiFilters": [

"armeabi-v7a",

"cppFlags": "",

}

四、实现串口异步回调

添加串口IPC客户端libserialport_service_api.z.so库，并且实现具体的异步回调功能

将libserialport_service_api.z.so复制到entry/libs/armeabi-a7v目录将库的头文件复制到entry/src/main/cpp/include目录继承SerialCallbackBase类，实现串口数据异步回调SerialAsyncCallback class SerialAsyncCallback: public SerialCallbackBase {

public:

SerialAsyncCallback() = default;

~SerialAsyncCallback();

// 通知回调事件

void OnCallBackEvent() override;

// 接收到串口数据

void OnRecvData(const uint8_t *buffer, uint32_t length) override;

...

};

修改src/main/cpp/CMakeList.txt文件 # the minimum version of CMake.

cmake_minimum_required(VERSION 3.4.1)

project(XComponent)

set(NATIVERENDER_ROOT_PATH ${CMAKE_CURRENT_SOURCE_DIR})

include_directories(${NATIVERENDER_ROOT_PATH}

${NATIVERENDER_ROOT_PATH}/include

)

link_directories(${NATIVERENDER_ROOT_PATH}/../../../libs/${CMAKE_OHOS_ARCH_ABI})

add_library(serialhelper SHARED serial_helper.cpp x_napi_tool.cpp serial_async_callback.cpp)

target_link_libraries(serialhelper PUBLIC libace_napi.z.so libc++.a libhilog_ndk.z.so libuv.so libserialport_service_api.z.so)

在napi函数中调用api函数，使用NAPI框架生成工具生成OpenSerial代码，如下： struct OpenSerial_value_struct {

std::string in0;

int32_t out;

};

void OpenSerial_execute(XNapiTool *pxt, void *data)

{

OpenSerial_value_struct *vio = (OpenSerial_value_struct *)data;

vio->out = get_serial_client()->OpenSerial(vio->in0);

}

void OpenSerial_complete(XNapiTool *pxt, void *data)

{

OpenSerial_value_struct *vio = (OpenSerial_value_struct *)data;

napi_value result = nullptr;

result = NUMBER_C_2_JS(pxt, Int32, vio->out);

{

napi_value args[XNapiTool::ARGV_CNT] = {result, nullptr};

pxt->FinishAsync(vio->out, args);

}

delete vio;

}

napi_value OpenSerial_middle(napi_env env, napi_callback_info info)

{

XNapiTool *pxt = std::make_unique(env, info).release();

if (pxt->IsFailed()) {

napi_value err = pxt->GetError();

delete pxt;

return err;

}

struct OpenSerial_value_struct *vio = new OpenSerial_value_struct();

pxt->SwapJs2CUtf8(pxt->GetArgv(0), vio->in0);

napi_value result = pxt->StartAsync(OpenSerial_execute, vio, OpenSerial_complete,

pxt->GetArgc() == 2 ? pxt->GetArgv(1) : nullptr);

if (pxt->IsFailed()) {

result = pxt->GetError();

}

return result;

}

模块注册 static napi_value init(napi_env env, napi_value exports)

{

std::shared_ptr pxt = std::make_shared(env, exports);

//js函数与C++函数映射

pxt->DefineFunction("setOptions", OHOS::SerialPort::SetOptions_middle);

pxt->DefineFunction("openSerial", OHOS::SerialPort::OpenSerial_middle);

pxt->DefineFunction("closeSerial", OHOS::SerialPort::CloseSerial_middle);

pxt->DefineFunction("clearBuffer", OHOS::SerialPort::ClearBuffer_middle);

pxt->DefineFunction("sendData", OHOS::SerialPort::SendData_middle);

pxt->DefineFunction("recvData", OHOS::SerialPort::RecvData_middle);

pxt->DefineFunction("transmit", OHOS::SerialPort::Transmit_middle);

pxt->DefineFunction("on", OHOS::SerialPort::on_middle);

pxt->DefineFunction("off", OHOS::SerialPort::off_middle);

pxt->DefineFunction("setGPIODirection", OHOS::SerialPort::setGPIODirection_middle);

pxt->DefineFunction("setGPIOValue", OHOS::SerialPort::setGPIOValue_middle);

pxt->DefineFunction("getGPIOValue", OHOS::SerialPort::getGPIOValue_middle);

return exports;

}

static napi_module g_serialHelper_Module = {

.nm_version = 1,

.nm_flags = 0,

.nm_filename = nullptr,

.nm_register_func = init,

.nm_modname = "serialhelper",

.nm_priv = ((void *)0),

.reserved = {(void *)0},

};

extern "C" __attribute__((constructor)) void Register_serialHelper_Module(void)

{

napi_module_register(&g_serialHelper_Module);

}

eTS调用接口验证

import serialHelper from "libserialhelper.so"

...

//打开串口this.tty /dev/ttyXRUSB0

serialHelper.openSerial(this.tty).then(()=>{

HiLog.i(TAG, "serial openSerial " + this.tty + " success")

this.status = '开'

}).catch((error)=> {

HiLog.i(TAG, "openSerial " + this.tty + " failed:" + error)

});

...

//设置为异步

serialHelper.on("/dev/ttyXRUSB0", (data) => {

var dataString = "";

for (var i = 0; i < data.length; i++) {

dataString += String.fromCharCode(data[i]);

}

HiLog.i(TAG, "ttyXRUSB0 len:" + data.length + " data:" + dataString);

})

应用启动后点击"打开/dev/ttyXRUSB0"按钮查看输出日志，出现serialport_client与serial_service_impl标志，表示访问串口服务成功

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夸智网

网络 harmonyos 华为 移动开发 IT互联网 OpenHarmony 串口服务访问

arm开发 运维 深入浅出 Linux 中的 ARM IOMMU SMMU I

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