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