c++编写node的addon(7) --object wrap

1.环境

Ubuntu 14.04

node 4.5.0

node-gyp 3.4.0

2.项目

新建项目，加入组件nan和bindings

方法一、在项目文件的node_modules中复制组件nan和bindings的全部代码包;

方法二、在package.json的dependencies中加入这两个组件，用nmp安装

3.c++源码

//myobject.h
#ifndef MYOBJECT_H
#define MYOBJECT_H

#include <nan.h>

class MyObject : public Nan::ObjectWrap {
 public:
  static void Init(v8::Local<v8::Object> exports);

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

  static void New(const Nan::FunctionCallbackInfo<v8::Value>& info);
  static void GetValue(const Nan::FunctionCallbackInfo<v8::Value>& info);
  static void PlusOne(const Nan::FunctionCallbackInfo<v8::Value>& info);
  static void Multiply(const Nan::FunctionCallbackInfo<v8::Value>& info);
  static Nan::Persistent<v8::Function> constructor;
  double value_;
};

#endif

//myobject.cc

#include "myobject.h"

Nan::Persistent<v8::Function> MyObject::constructor;

MyObject::MyObject(double value) : value_(value) {
}

MyObject::~MyObject() {
}

void MyObject::Init(v8::Local<v8::Object> exports) {
  Nan::HandleScope scope;

  // Prepare constructor template
  v8::Local<v8::FunctionTemplate> tpl = Nan::New<v8::FunctionTemplate>(New);
  tpl->SetClassName(Nan::New("MyObject").ToLocalChecked());
  tpl->InstanceTemplate()->SetInternalFieldCount(1);

  // Prototype
  Nan::SetPrototypeMethod(tpl, "value", GetValue);
  Nan::SetPrototypeMethod(tpl, "plusOne", PlusOne);
  Nan::SetPrototypeMethod(tpl, "multiply", Multiply);

  constructor.Reset(tpl->GetFunction());
  exports->Set(Nan::New("MyObject").ToLocalChecked(), tpl->GetFunction());
}

void MyObject::New(const Nan::FunctionCallbackInfo<v8::Value>& info) {
  if (info.IsConstructCall()) {
    // Invoked as constructor: `new MyObject(...)`
    double value = info[0]->IsUndefined() ? 0 : info[0]->NumberValue();
    MyObject* obj = new MyObject(value);
    obj->Wrap(info.This());
    info.GetReturnValue().Set(info.This());
  } else {
    // Invoked as plain function `MyObject(...)`, turn into construct call.
    const int argc = 1;
    v8::Local<v8::Value> argv[argc] = { info[0] };
    v8::Local<v8::Function> cons = Nan::New<v8::Function>(constructor);
    info.GetReturnValue().Set(cons->NewInstance(argc, argv));
  }
}

void MyObject::GetValue(const Nan::FunctionCallbackInfo<v8::Value>& info) {
  MyObject* obj = ObjectWrap::Unwrap<MyObject>(info.Holder());
  info.GetReturnValue().Set(Nan::New(obj->value_));
}

void MyObject::PlusOne(const Nan::FunctionCallbackInfo<v8::Value>& info) {
  MyObject* obj = ObjectWrap::Unwrap<MyObject>(info.Holder());
  obj->value_ += 1;
  info.GetReturnValue().Set(Nan::New(obj->value_));
}

void MyObject::Multiply(const Nan::FunctionCallbackInfo<v8::Value>& info) {
  MyObject* obj = ObjectWrap::Unwrap<MyObject>(info.Holder());
  double multiple = info[0]->IsUndefined() ? 1 : info[0]->NumberValue();

  v8::Local<v8::Function> cons = Nan::New<v8::Function>(constructor);

  const int argc = 1;
  v8::Local<v8::Value> argv[argc] = { Nan::New(obj->value_ * multiple) };

  info.GetReturnValue().Set(cons->NewInstance(argc, argv));
}

//addon.cc

#include <nan.h>
#include "myobject.h"

void InitAll(v8::Local<v8::Object> exports) {
  MyObject::Init(exports);
}

NODE_MODULE(addon, InitAll)

4.binding.gyp

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

5.js源码

var addon = require('bindings')('addon');

var obj = new addon.MyObject(10);

console.log(obj.plusOne());
console.log(obj.plusOne());
console.log(obj.plusOne());

console.log(obj.multiply().value());
console.log(obj.multiply(10).value());

var newobj = obj.multiply(-1);
console.log(newobj.value());
console.log(obj === newobj);

6. 编译addon

cd到源码目录下

node-gyp configure build   

7.执行

cd 到源码目录下

node hello.js