Subj : spidermonkey: api question
To   : netscape.public.mozilla.jseng
From : Jens Thiele
Date : Fri Jan 07 2005 11:37 am

Hi,

this is related to:
http://groups.google.de/groups?selm=8nhdmc.rk2.ln%40karme.myfqdn.de

i am trying again to remove this hack:

    // we want to use the same [[Class]] but a different constructor
    // alternatively we could nearly duplicate JS_InitClass (but perhaps
    // this would also require to use non-public spidermonkey API functions)
    const char *tmp=BaseWrapper_class.name;
    BaseWrapper_class.name="Sub";
    JSObject* subproto;
    subproto=JS_InitClass(cx,global,BaseWrapper_proto, &BaseWrapper_class,
			  SubWrapper_cons, 0, NULL, SubWrapper_methods,
			  NULL, NULL);
    BaseWrapper_class.name=tmp;
    if (!subproto) return JS_FALSE;
    return JS_TRUE;

(used here:
<http://egachine.berlios.de/embedding-sm-best-practice/ar01s05.html#id2526656>
)

it seems it is possible to duplicate enough of JS_InitClass with public
API functions - except that one cannot set the clasp member of the
JSFunction struct of the constructor:

// nearly a duplicate of JS_InitClass
JSObject*
ejs_WrapClass(JSContext *cx, JSObject *obj, const char* consname,
   	      JSObject *parent_proto,
	      JSNative constructor, JSFunctionSpec *methods)
  {
    // create prototype object
    JSObject* proto;
    if (!(proto=JS_NewObject(cx, NULL, parent_proto, obj))) return NULL;

    // constructor
    JSFunction *jscons;
    if (!(jscons=JS_DefineFunction(cx, obj, consname, constructor, 0,
0))) return NULL;

    // NOT PART OF PUBLIC API
    jscons->clasp = &CppClass;

    // set constructor.prototype
    if (!JS_DefineProperty(cx, jscons->object, "prototype", 	
	OBJECT_TO_JSVAL(proto),
	JS_PropertyStub, JS_PropertyStub, JSPROP_READONLY | 	
	JSPROP_PERMANENT))
      return NULL;
    // set constructor.prototype.constructor
    if (!JS_DefineProperty(cx, proto, "constructor",
OBJECT_TO_JSVAL(jscons->object),
			   JS_PropertyStub, JS_PropertyStub, JSPROP_READONLY | JSPROP_PERMANENT))
      return NULL;

    if (!JS_DefineFunctions(cx, proto, methods)) return NULL;

    return proto;
  }


did I miss something?
could something like JS_SetClass(JSFunction *) be added to the public
API?

Jens

.