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doc: cleanup addons code, fix isolate positioning
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isolate declaration global and above `using namespace v8`
removed BUILDING_NODE_EXTENSION and tidied up code
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@rvagg @bnoordhuis
rvagg authored and bnoordhuis committed Jun 18, 2013
1 parent 98aad77 commit d3b06f1
Showing 1 changed file with 28 additions and 38 deletions.
66 changes: 28 additions & 38 deletions doc/api/addons.markdown
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Original file line number Diff line number Diff line change
Expand Up @@ -39,13 +39,11 @@ the following JavaScript code:
First we create a file `hello.cc`:

#include <node.h>
#include <v8.h>

Isolate* isolate = Isolate::GetCurrent();

using namespace v8;

Handle<Value> Method(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);
return scope.Close(String::New("world"));
}
Expand Down Expand Up @@ -140,14 +138,12 @@ The following pattern illustrates how to read arguments from JavaScript
function calls and return a result. This is the main and only needed source
`addon.cc`:

#define BUILDING_NODE_EXTENSION
#include <node.h>

Isolate* isolate = Isolate::GetCurrent();

using namespace v8;

Handle<Value> Add(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);

if (args.Length() < 2) {
Expand Down Expand Up @@ -185,14 +181,12 @@ You can test it with the following JavaScript snippet:
You can pass JavaScript functions to a C++ function and execute them from
there. Here's `addon.cc`:

#define BUILDING_NODE_EXTENSION
#include <node.h>

Isolate* isolate = Isolate::GetCurrent();

using namespace v8;

Handle<Value> RunCallback(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);

Local<Function> cb = Local<Function>::Cast(args[0]);
Expand Down Expand Up @@ -230,14 +224,12 @@ You can create and return new objects from within a C++ function with this
`addon.cc` pattern, which returns an object with property `msg` that echoes
the string passed to `createObject()`:

#define BUILDING_NODE_EXTENSION
#include <node.h>

Isolate* isolate = Isolate::GetCurrent();

using namespace v8;

Handle<Value> CreateObject(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);

Local<Object> obj = Object::New();
Expand Down Expand Up @@ -267,23 +259,23 @@ To test it in JavaScript:
This pattern illustrates how to create and return a JavaScript function that
wraps a C++ function:

#define BUILDING_NODE_EXTENSION
#include <node.h>

Isolate* isolate = Isolate::GetCurrent();

using namespace v8;

Handle<Value> MyFunction(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);
return scope.Close(String::New("hello world"));
}

Handle<Value> CreateFunction(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);

Local<FunctionTemplate> tpl = FunctionTemplate::New(MyFunction);
Local<Function> fn = tpl->GetFunction();

// omit this to make it anonymous
fn->SetName(String::NewSymbol("theFunction"));

Expand All @@ -297,7 +289,6 @@ wraps a C++ function:

NODE_MODULE(addon, Init)


To test:

var addon = require('./build/Release/addon');
Expand All @@ -312,7 +303,6 @@ Here we will create a wrapper for a C++ object/class `MyObject` that can be
instantiated in JavaScript through the `new` operator. First prepare the main
module `addon.cc`:

#define BUILDING_NODE_EXTENSION
#include <node.h>
#include "myobject.h"

Expand Down Expand Up @@ -350,32 +340,34 @@ And in `myobject.cc` implement the various methods that you want to expose.
Here we expose the method `plusOne` by adding it to the constructor's
prototype:

#define BUILDING_NODE_EXTENSION
#include <node.h>
#include "myobject.h"

Isolate* isolate = Isolate::GetCurrent();

using namespace v8;

MyObject::MyObject() {};
MyObject::~MyObject() {};

void MyObject::Init(Handle<Object> exports) {
Isolate* isolate = Isolate::GetCurrent();

// Prepare constructor template
Local<FunctionTemplate> tpl = FunctionTemplate::New(New);
tpl->SetClassName(String::NewSymbol("MyObject"));
tpl->InstanceTemplate()->SetInternalFieldCount(1);

// Prototype
tpl->PrototypeTemplate()->Set(String::NewSymbol("plusOne"),
FunctionTemplate::New(PlusOne)->GetFunction());

Persistent<Function> constructor =
Persistent<Function>::New(isolate, tpl->GetFunction());
Persistent<Function> constructor
= Persistent<Function>::New(isolate, tpl->GetFunction());

exports->Set(String::NewSymbol("MyObject"), constructor);
}

Handle<Value> MyObject::New(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);

MyObject* obj = new MyObject();
Expand All @@ -386,6 +378,7 @@ prototype:
}

Handle<Value> MyObject::PlusOne(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);

MyObject* obj = ObjectWrap::Unwrap<MyObject>(args.This());
Expand All @@ -403,7 +396,6 @@ Test it with:
console.log( obj.plusOne() ); // 12
console.log( obj.plusOne() ); // 13


### Factory of wrapped objects

This is useful when you want to be able to create native objects without
Expand All @@ -415,15 +407,13 @@ explicitly instantiating them with the `new` operator in JavaScript, e.g.

Let's register our `createObject` method in `addon.cc`:

#define BUILDING_NODE_EXTENSION
#include <node.h>
#include "myobject.h"

Isolate* isolate = Isolate::GetCurrent();

using namespace v8;

Handle<Value> CreateObject(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);
return scope.Close(MyObject::NewInstance(args));
}
Expand All @@ -440,7 +430,6 @@ Let's register our `createObject` method in `addon.cc`:
In `myobject.h` we now introduce the static method `NewInstance` that takes
care of instantiating the object (i.e. it does the job of `new` in JavaScript):

#define BUILDING_NODE_EXTENSION
#ifndef MYOBJECT_H
#define MYOBJECT_H

Expand All @@ -465,12 +454,9 @@ care of instantiating the object (i.e. it does the job of `new` in JavaScript):

The implementation is similar to the above in `myobject.cc`:

#define BUILDING_NODE_EXTENSION
#include <node.h>
#include "myobject.h"

Isolate* isolate = Isolate::GetCurrent();

using namespace v8;

MyObject::MyObject() {};
Expand All @@ -479,10 +465,12 @@ The implementation is similar to the above in `myobject.cc`:
Persistent<Function> MyObject::constructor;

void MyObject::Init() {
Isolate* isolate = Isolate::GetCurrent();
// Prepare constructor template
Local<FunctionTemplate> tpl = FunctionTemplate::New(New);
tpl->SetClassName(String::NewSymbol("MyObject"));
tpl->InstanceTemplate()->SetInternalFieldCount(1);

// Prototype
tpl->PrototypeTemplate()->Set(String::NewSymbol("plusOne"),
FunctionTemplate::New(PlusOne)->GetFunction());
Expand All @@ -491,6 +479,7 @@ The implementation is similar to the above in `myobject.cc`:
}

Handle<Value> MyObject::New(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);

MyObject* obj = new MyObject();
Expand All @@ -501,6 +490,7 @@ The implementation is similar to the above in `myobject.cc`:
}

Handle<Value> MyObject::NewInstance(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);

const unsigned argc = 1;
Expand All @@ -511,6 +501,7 @@ The implementation is similar to the above in `myobject.cc`:
}

Handle<Value> MyObject::PlusOne(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);

MyObject* obj = ObjectWrap::Unwrap<MyObject>(args.This());
Expand Down Expand Up @@ -541,20 +532,19 @@ by unwrapping them with Node's `node::ObjectWrap::Unwrap` helper function.
In the following `addon.cc` we introduce a function `add()` that can take on two
`MyObject` objects:

#define BUILDING_NODE_EXTENSION
#include <node.h>
#include "myobject.h"

Isolate* isolate = Isolate::GetCurrent();

using namespace v8;

Handle<Value> CreateObject(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);
return scope.Close(MyObject::NewInstance(args));
}

Handle<Value> Add(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);

MyObject* obj1 = node::ObjectWrap::Unwrap<MyObject>(
Expand All @@ -581,7 +571,6 @@ In the following `addon.cc` we introduce a function `add()` that can take on two
To make things interesting we introduce a public method in `myobject.h` so we
can probe private values after unwrapping the object:

#define BUILDING_NODE_EXTENSION
#ifndef MYOBJECT_H
#define MYOBJECT_H

Expand All @@ -606,12 +595,9 @@ can probe private values after unwrapping the object:

The implementation of `myobject.cc` is similar as before:

#define BUILDING_NODE_EXTENSION
#include <node.h>
#include "myobject.h"

Isolate* isolate = Isolate::GetCurrent();

using namespace v8;

MyObject::MyObject() {};
Expand All @@ -620,15 +606,18 @@ The implementation of `myobject.cc` is similar as before:
Persistent<Function> MyObject::constructor;

void MyObject::Init() {
Isolate* isolate = Isolate::GetCurrent();

// Prepare constructor template
Local<FunctionTemplate> tpl = FunctionTemplate::New(New);
tpl->SetClassName(String::NewSymbol("MyObject"));
tpl->InstanceTemplate()->SetInternalFieldCount(1);

constructor = Persistent<Function>::New(tpl->GetFunction());
constructor = Persistent<Function>::New(isolate, tpl->GetFunction());
}

Handle<Value> MyObject::New(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);

MyObject* obj = new MyObject();
Expand All @@ -639,6 +628,7 @@ The implementation of `myobject.cc` is similar as before:
}

Handle<Value> MyObject::NewInstance(const Arguments& args) {
Isolate* isolate = Isolate::GetCurrent();
HandleScope scope(isolate);

const unsigned argc = 1;
Expand Down

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