详解nodejs addon实现回调函数事件

npm install nan

{
    'targets': [
    {
        "target_name": "bjcast_project_addon", 
        "sources": ["./bjcast_project_addon.cc"],
        
        "include_dirs": [
            "<!(node -e \"require('nan')\")",
        ],            
    }
    ]  
}

#include <iostream>
#include <string>

#include <v8.h>
#include <nan.h>
#include<windows.h>
using namespace v8;

struct OnStartSessionData {
  Nan::Callback *callback;    //回调函数
  int reason;                 //需要回调到js层的数据
  uv_async_t handle;          //异步句柄
};

OnStartSessionData *on_start_session_data = new OnStartSessionData();

static void OnBJCastStartSession(const int reason) {    
  on_start_session_data->reason = reason;
  on_start_session_data->handle.data = (void *)on_start_session_data; //数据类型的一些转换
  uv_async_send(&on_start_session_data->handle);                      //唤醒事件循环中的事件  
}

void OnStartSessionEvent(uv_async_t *handle) {                  //具体执行的事件
  Nan::HandleScope scope;
  OnStartSessionData *data = (OnStartSessionData *)handle->data;
  v8::Local<v8::Value> argv[1] = {Nan::New((int)data->reason)};//数据类型的一些转换
  data->callback->Call(1, argv);                               //数据回调到js层
}

NAN_METHOD(bjcast_session) {
  Local<String> ip_value = Local<String>::Cast(info[0]);
  String::Utf8Value ip(ip_value);
  std::string ip_str = std::string(*ip);

  Local<Number> port_value = Local<Number>::Cast(info[1]);
  double port = port_value->NumberValue();

  Local<String> pin_value = Local<String>::Cast(info[2]);
  String::Utf8Value pin(pin_value);
  std::string pin_str = std::string(*pin);

  Nan::Callback *start_session_callback = new Nan::Callback(info[3].As<Function>());
   
  on_start_session_data->callback = start_session_callback;  //获取回调函数 
  uv_async_init(uv_default_loop(), &on_start_session_data->handle,OnStartSessionEvent);  //加入事件循环中，等待唤醒，uv_default_loop()获取libuv默认创建的事件循环句柄

//   int32_t value = BJCastProjectLib::GetInstance().StartBJCastSession(
//       ip_str.c_str(), (uint16_t)port, pin_str.c_str(),start_session_callback);
  
  int value = 0;
  Local<Value> argv[1] = {Nan::New((int)value)};
  info.GetReturnValue().Set(Nan::New((int)value));

  OnBJCastStartSession(5);   
}


NAN_MODULE_INIT(init) {
  Nan::Export(target, "startBJCastSession", bjcast_session);
}

NODE_MODULE(bjcast_project_addon_win, init)

var BJLib = require('./build/Release/bjcast_project_addon.node');

var serverIp = '192.168.9.155';
var serverPort = 8188;
var pin = '';


onStartSessionResult =function(result) {  
  console.log('result =  ', result);
}

var ret_value = BJLib.startBJCastSession(
    serverIp, serverPort, pin, onStartSessionResult);  

console.log(ret_value);

node index.js
0
result =   5