Nan Simple Callback Helper

callback_helper.cpp

typedef void (*callback_helper_cb)(void* self, v8::Isolate* isolate, const v8::Persistent<v8::Function>& callback);

struct callback_helper_data {
    v8::Persistent<v8::Function> callback;
    void* self;
    callback_helper_cb cb;
};

#define CALLBACK_HELPER_CALL(A, B) v8::Local<v8::Function>::New(isolate, callback)->Call(isolate->GetCurrentContext()->Global(), A, B)

uv_async_t* callback_helper(v8::Isolate* isolate, const v8::Local<v8::Function>& func, void* self, callback_helper_cb cb = NULL) {
    uv_async_t* async = new uv_async_t();
    callback_helper_data* data = new callback_helper_data();
    data->callback.Reset(isolate, func);
    data->self = self;
    data->cb = cb;
    async->data = data;
    uv_async_init(uv_default_loop(), async, [](uv_async_t* handle){
        LOG("event loop callback");
        auto isolate = v8::Isolate::GetCurrent();
        v8::HandleScope handleScope(isolate);
        callback_helper_data* data = (callback_helper_data*)handle->data;
        
        if (data->cb != NULL) {
            data->cb(data->self, isolate, data->callback);
        } else {
            v8::Local<v8::Function>::New(isolate, data->callback)->Call(isolate->GetCurrentContext()->Global(), 0, 0);
        }
        data->callback.Reset();
        delete data;
        delete handle;
        
    });
    return async;
}

usage.cpp

NAN_METHOD(MyClient::Open) {
    v8::Isolate* isolate = info.GetIsolate();
    auto self = SELF(MyClient); 
    auto nodeFunc = info[0].As<v8::Function>();
    auto async = callback_helper(isolate, nodeFunc, self, [](void* s, v8::Isolate* isolate, const v8::Persistent<v8::Function>& callback) {
        MyClient* self = (MyClient*)s;
        const char* state = self->client->getStateAsString();
        v8::Handle<v8::Value> argv[] = { STR(state) };
//        v8::Local<v8::Function>::New(isolate, callback)->Call(isolate->GetCurrentContext()->Global(), 0, 0);
        CALLBACK_HELPER_CALL(1, argv);
    });

    self->client->open([async](ClientResult result) {
        LOG("Client open");
        uv_async_send(async);
    });
}