Verified getters work with internal fields in v8

v8_internal_fields_and_getters.go

package main

import (
 	v8 "rogchap.com/v8go"
)

type v8BuiltIns struct {
	Object struct {
		create         *v8.Function
		defineProperty *v8.Function
	}
}

func initBuiltins(ctx *v8.Context) v8BuiltIns {
	objectGlobal, err := ctx.Global().Get("Object")
	if err != nil {
		panic(err)
	}
	defPropV, err := objectGlobal.Object().Get("defineProperty")
	if err != nil {
		panic(err)
	}
	defPropFn, err := defPropV.AsFunction()
	if err != nil {
		panic(err)
	}
	createV, err := objectGlobal.Object().Get("create")
	if err != nil {
		panic(err)
	}
	createFn, err := createV.AsFunction()
	if err != nil {
		panic(err)
	}
	return v8BuiltIns{
		Object: struct {
			create         *v8.Function
			defineProperty *v8.Function
		}{
			create:         createFn,
			defineProperty: defPropFn,
		},
	}
}

func main() {
	iso := v8.NewIsolate()
	ctx := v8.NewContext(iso)
	builtins := initBuiltins(ctx)
	ot := v8.NewObjectTemplate(iso)
	ot.SetInternalFieldCount(1)
	o, err := ot.NewInstance(ctx)
	if err != nil {
		panic(err)
	}
	v, err := v8.NewValue(iso, "secret")
	if err != nil {
		panic(err)
	}
	if err := o.SetInternalField(0, v); err != nil {
		panic(err)
	}

	getterOptV, err := builtins.Object.create.Call(ctx.Global(), v8.Null(iso))
	if err != nil {
		panic(err)
	}
	getterObject, err := getterOptV.AsObject()
	if err != nil {
		panic(err)
	}
	if err := getterObject.Set("get", v8.NewFunctionTemplate(iso, func(info *v8.FunctionCallbackInfo) *v8.Value {
		fmt.Println("running getter")
		return info.This().GetInternalField(0)
	}).GetFunction(ctx).Value); err != nil {
		panic(err)
	}
	internalFieldName, err := v8.NewValue(iso, "internal")
	if err != nil {
		panic(err)
	}
	_, err = builtins.Object.defineProperty.Call(ctx.Global(), o, internalFieldName, getterObject)
	if err != nil {
		panic(err)
	}

	// test if getting internal field returns `secret`
	v, err = o.Get("internal")
	if err != nil {
		panic(err)
	}
	if v.String() != "secret" {
		panic("expected secret")
	}

	if err := ctx.Global().Set("o", o); err != nil {
		panic(err)
	}
	_, err = ctx.RunScript("var p = o", "")
	if err != nil {
		panic(err)
	}

	i, err := ctx.Global().Get("p")
	if err != nil {
		panic(err)
	}
	v, err = i.Object().Get("internal")
	if err != nil {
		panic(err)
	}
	if v.String() != "secret" {
		panic("expected secret")
	}

	v, err = ctx.RunScript("o.internal", "")
	if err != nil {
		panic(err)
	}
	if v.String() != "secret" {
		panic("expected secret")
	}
}