Good day, Xiang.
First of all, I think you'd better off keeping an interceptor on the
objects. If you're still determined to keep it on the prototype, you
should be able to find an object, but you will have to traversal from
the This of AccessorInfo. Please note that is somewhat fragile as one
can change prototype chain.
yours,
anton.
On Tue, Dec 1, 2009 at 3:11 PM, Xiang Zhong <clock...@gmail.com> wrote:
> Hi, All,
> There are two object involved:
> Prototype
> ^
> |
> |
> Object
>
> I set interceptor on prototype template, and have set internal field on
> Object.
> Is there a way to access these internal field of Object in intercrptor of
> Prototype?
>
>
> For Accessor, there is a way to define signature, then the VM will pass the
> right object to accessor, how about inteceptors?
>
> Please check the following sample, it will crash if I try a access the
> internal filed.
>
> #include <v8.h>
> #include <iostream>
> #include <fstream>
> #include <sstream>
> #include <cmath>
> using namespace v8;
> v8::Handle<v8::Value> Getter(v8::Local<v8::String> propertyName,const
> v8::AccessorInfo &info) {
> v8::HandleScope handleScope;
> v8::Handle<v8::External> external =
> v8::Handle<v8::External>::Cast(info.Holder()->GetInternalField(0));
> void * message = external->Value();
> const char * str = (const char *)message;
> printf(str);
> //return something that is not NULL back
> return v8::True();
> }
> Handle<Value> CreateObjectWithInteceptor(const Arguments& args)
> {
> HandleScope handleScope;
> const char * test = "With Inteceptor";
> v8::Handle<v8::External> external = v8::External::New((void *)test);
> args.Holder()->SetInternalField(0, external);
> return args.Holder();
> }
> int main()
> {
> HandleScope handleScope;
>
> Handle<FunctionTemplate> functionTemplate =
> FunctionTemplate::New(CreateObjectWithInteceptor);
> functionTemplate->SetClassName(String::New("CreateObjectWithInteceptor"));
> v8::Local<v8::Signature> default_signature =
> v8::Signature::New(functionTemplate);
> Handle<ObjectTemplate> instanceTemplate =
> functionTemplate->InstanceTemplate();
> instanceTemplate->SetInternalFieldCount(1); // create an internal field for
> the C++ object
> Handle<ObjectTemplate> prot = functionTemplate->PrototypeTemplate();
> prot->SetNamedPropertyHandler(Getter);
>
> Handle<ObjectTemplate> globals = ObjectTemplate::New();
> globals->Set(String::New("object"), instanceTemplate); // add our print
> function
> Persistent<Context> context = Context::New(0, globals);
> Context::Scope contextScope(context);
> Handle<Script> script = Script::Compile(v8::String::New("object.getValue"));
> Handle<Value> result = script->Run();
> context.Dispose();
> return 0;
> }
>
> Cheers~
> Xiang
>
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