On Wed, Mar 7, 2012 at 3:16 AM, cruisercoder <[email protected]> wrote:
> How do I get internal data for function callbacks? The approach I'm
> currently taking is to use the function's prototype object where I can
> declare an internal field and then set it at context time. However,
> I get an error about the internal field count when I retrieve the
> prototype and try to set data (code and error shown below).
>
> I'm also not sure about how to unpack the data in the handler.
>
> erik
>
>
> v8::Handle<v8::Value> myHandler(const v8::Arguments& args) {
> nd::unused(args);
> using namespace v8;
> return Undefined();
> }
>
>
> using namespace v8;
> HandleScope handle_scope;
>
> v8::Persistent<v8::ObjectTemplate> global_template =
> Persistent<ObjectTemplate>::New(ObjectTemplate::New());
>
> Handle<FunctionTemplate> tmpl = FunctionTemplate::New(myHandler);
>
> Handle<ObjectTemplate> proto_t = tmpl->PrototypeTemplate();
> proto_t->SetInternalFieldCount(1);
>
> global_template->Set(String::New("myFunction"),tmpl);
>
> Persistent<Context> context = Context::New(0, global_template);
>
> Context::Scope context_scope(context);
>
> Handle<Function> fn = tmpl->GetFunction();
> Handle<Object> proto = Handle<Object>::Cast(fn->GetPrototype());
GetPrototype() is a method of Object and returns object's __proto__
(which I guess is "Function.prototype" in this case). You want
fn.Get(String::New("prototype")).
Not quite sure what you're trying to achieve, but you can also
register callback data in FunctionTemplate::New (the "data" parameter)
which will be passed into your callback as Arguments::Data().
Matthias
>
> void *data(0);
> proto->SetInternalField(0, External::New(data));
>
>
>
> #
> # Fatal error in v8::Object::SetInternalField()
> # Writing internal field out of bounds
> #
>
>
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