Subj : Re: beginner question spidermonkey
To   : netscape.public.mozilla.jseng
From : marian simon
Date : Sat Sep 04 2004 11:27 pm

hi,
thanks for yout hint. I think you didn't understand exaxtly what my problem
was,but now (by your answer) I get ahead.
(my function getname() was just a dummy-callback for debuging-purpose)
I just have some startup-problems with the spidermonkey interface concept,
( not with C or C-syntax).
( It's not easy to ask a proper question if I don'k exactly know  what I'm
talking about ... :-) )
I have already added some functions to a SVG-player and now I want to add JS
for DOM.

It is necessary to call "JS_NewObject" if my "C" function returns a pointer,
and store the pointer in private data.
When is this new JSObject deleted ???

This is how I now think it schould work:

static JSBool getElementById (JSContext *cx, JSObject *obj, uintN argc,
jsval *argv, jsval *rval)
{
int i;
JSObject *myobj;
argc--;

i=JSVAL_TO_INT(argv[argc]);
ele=doc->list[i];

 if(JSVAL_IS_OBJECT(*rval))                 //is this required ???
 {                                                               // no new
object because already exists ?
 if(! (myobj=JSVAL_TO_OBJECT(*rval)))
     return JS_FALSE;

  if( ! JS_SetPrivate(cx, myobj, (void*) ele))
   return JS_FALSE;

  *rval = OBJECT_TO_JSVAL(myobj);
 }else
 {                                                              // create
new object and save my private pointer
                                                                // new ok,
but when delete ? automatic ?
    myobj = JS_NewObject(cx, &element_class,js_element,NULL);

      if( ! JS_SetPrivate(cx, myobj, (void*) ele))
        return JS_FALSE;

  *rval = OBJECT_TO_JSVAL(myobj);
 }

 return JS_TRUE;
}



"Sterling Bates" <whoelse@sterlingbates.com> schrieb im Newsbeitrag
news:ch8cpm$cuc1@ripley.netscape.com...
> (I just received this today, but the date was August 26...?)
>
> "marian simon" <marians@gmx.at> wrote in message
> news:ch83nk$d741@ripley.netscape.com...
> > static JSBool getName (JSContext *cx, JSObject *obj, uintN argc, jsval
> > *argv, jsval *rval)
> > {
> > char *name;
> >
> >     name=ele->get_name();  //not good ??
> >    printf("get_Name() name = %s obj=0x%x argc=%d \n",name,obj,argc);
> >
> > return JS_TRUE;
> > }
>
> I'm not sure if this is a typo, but you're not setting *rval to the actual
> name.  Brendan'll correct me if I'm wrong, but you probably want this:
>
>     JSString *str;
>     str = JS_NewString(cx, name, strlen(name));
>     *rval = STRING_TO_JSVAL(str);
>
> strlen() may not be right, but I don't recall C[++]'s string length
function
> :)  Also, it may not be right to create a new JSString for every function
> call, but aside from making that a property of the object I don't know any
C
> solutions.
>
> Sterling
>
>

.