Re: Object creation in SpiderMonkey 45

On Thursday, May 5, 2016 at 6:19:24 PM UTC+3, Mihai Dobrescu wrote:
> On Thursday, May 5, 2016 at 6:06:29 PM UTC+3, Boris Zbarsky wrote:
> > On 5/5/16 8:56 AM, Mihai Dobrescu wrote:
> > > but for some reason it doesn't call the custom toString when it is
> > > created this way. Any hints?
> > 
> > Where does the custom toString live?  In your examples:
> > 
> > var ap1 = new AIRealPoint(3, 3);
> > var r = new AIReal(3);
> > 
> > is it the case that Object.getPrototypeOf(r) ==
> > Object.getPrototypeOf(ap1.h)?
> > 
> > Or put another way, when you say "h and v properties are defined using a 
> > templated function, basically creating a custom object of type AIReal 
> > (in this case) to return, using JS_NewObject", how _exactly_ are you 
> > doing this?  What does the JS_NewObject callsite look like?
> > 
> > -Boris
> 
> I have a construction as follows:
> 
> const JSFunctionSpec jsAIReal::fFunctions[] = {
>     JS_FN("toString", jsAIReal::ToString, 0, JSPROP_PERMANENT | JSPROP_ENUMERATE),
>     ...
> 
>     JS_FS_END
> }
> 
> passed to JS_InitClass (in a template class...):
> 
> static void DefineClass(JSContext *cx, JS::Handle<JSObject*> global)
>     {
>         try
>         {
> 
> jsType::fProtoObj = JS_InitClass(cx, global,
>                 nullptr, &fClass,
>                 Constructor, jsType::fConstructorNumberOfArguments,
>                 jsType::fProperties, jsType::fFunctions, jsType::fStaticProperties, jsType::fStaticFunctions);
> 
>             if (!jsType::fProtoObj)
>             {
>                 throw new jsEngineException("jsEngine error at definiton of %s.", fClass.name);
>             }
> }
>         catch (...)
>         {
>             throw new jsEngineException("jsEngine error at definiton of %s.", fClass.name);
>         }
>     }
> 
> A property getter looks like:
> 
> template<typename jsType, typename jsPropertyType, typename jsPropertyType::PrivateType PrivateType::*Property>
>     static bool GetProperty(JSContext *cx, unsigned argc, JS::Value *vp)
>     {
>         JS::CallArgs args = CallArgsFromVp(argc, vp);
> 
>         PrivateType* data = (PrivateType*)(JS_GetPrivate(&args.thisv().toObject()));
> 
>         if (!data)
>             return false; // +throw error...
> 
>         JSObject *obj = JS_NewObject(cx, &jsDataClass<jsPropertyType>::fClass);
> 
>         JS_SetPrivate(obj, new jsPropertyType::PrivateType(data->*Property));
> 
>         args.rval().setObject(*obj);
> 
>         return true;
>     }
> 
> used as follows:
> 
> const JSPropertySpec jsAIRealPoint::fProperties[] = {
> 	CLASS_JS_PSGS_PROPERTY(jsAIRealPoint, jsAIReal, h),
> 	CLASS_JS_PSGS_PROPERTY(jsAIRealPoint, jsAIReal, v),
> 
>     JS_PS_END
> };
> 
> where I have:
> 
> #define CLASS_JS_PSGS_PROPERTY(JS_TYPE, JS_PROPERTY_TYPE, PROPERTY) \
> JS_PSGS(#PROPERTY, (JS_TYPE::GetProperty<JS_TYPE, JS_PROPERTY_TYPE, &JS_TYPE::PrivateType::PROPERTY>), \
>                    (JS_TYPE::SetProperty<JS_TYPE, JS_PROPERTY_TYPE, &JS_TYPE::PrivateType::PROPERTY>), JSPROP_PERMANENT | JSPROP_ENUMERATE)
> 
> A bit hard to read this...sorry.
> 
> Note, it worked fine in 38.

Initially, I have set 0 for the functions flags (now, out of curiousity, I have JSPROP_PERMANENT | JSPROP_ENUMERATE, which is just for testing).