Subj : Re: updated jsgen (maybe rc1?) - beta 7
To   : netscape.public.mozilla.jseng
From : Marcello Bastea-Forte <marcello@TEHSPAMcellosoft.com>
Date : Sun Jan 04 2004 01:10 am

Ok, I finally updated jsgen (beta 7) to hopefully address all these 
problems.

I've completely rewritten almost all of the documentation, and revised a 
ton of the code:

http://www.cs.unm.edu/~cello/jsgen/

Changelog

# Rewrote quite a few bits of jsgen:
     * Cleaned up code in general
     * Commented somewhat complex code in jsgenjs.cpp, and added some 
descriptions in jsgen.cpp
     * Removed object caching on JSInit (may be slightly slower, but 
fixes bugs)
     * Reworked how function/constructor arguments work so that it 
supports "special" arguments more cleanly
     * Removed context caching and related getContext() function, in 
favor of a special argument of type JSContext*
     * Made uintN argc and jsval* argv special arguments, so they can be 
used in combination with other arguments
     * Added ability to get the "this" JSObject* with special argument 
JSObject* _this
     * Added JSString* special type

# Restructured docs
     * Cleaned up docs a bit
     * Added Usage Notes section
     * Added Makefile Pointers section

-----------------

And in reply to the previous post...

> Also, you're not worrying about thread safety -- do you plan to handle 
> multiple threads some day?  Threads are the main motivation for 
> contexts; a single-threaded embedding might use more than one context 
> (in fact, Mozilla's DOM does), but strictly speaking it need not, 
> because there are no thread-safety hazards requiring more than one context.

I'm not sure how I should be worrying about that.

> But to get back to your question: there's no need to call 
> JS_InitClass(cx, obj, ...) more than once per obj.

I know that there's no need, but it's more of a matter that my code 
*might* call initclass multiple times.  In beta 7, I'm now using the 
following code:

JSObject *JSTest::JSInit(JSContext *cx, JSObject *obj) {
	if (obj==NULL)
		obj = JS_GetGlobalObject(cx);
	jsval oldobj;
	if (JS_TRUE == JS_GetProperty(cx, obj, "JSTest", &oldobj) && 
!JSVAL_IS_VOID(oldobj))
		return JSVAL_TO_OBJECT(oldobj);
	return JS_InitClass(cx, obj, NULL, &JSTest::_jsClass,
     	                                 JSTest::JSConstructor, 0,
     	                                 JSTest::_JSPropertySpec, 
JSTest::_JSFunctionSpec,
     	                                 JSTest::_JSPropertySpec_static, 
JSTest::_JSFunctionSpec_static);
}

This should theoretically check if the class was already initialized in 
obj and won't initialize it more than once.

I don't know if this is the most efficient way to do it, but it works.

> Explicitly parameterize?  The JS API has many entry points whose 
> parameter lists begin (JSContext *cx, JSObject *obj...) and obj is the 
> parameter independent of cx telling in which object to define a class or 
> property, e.g.

I'm also using JS_GetGlobalObject to get around not having a JSObject * 
all the time.  I should probably add JSObject *obj as an optional 
parameter on getJSObject(JSContext *cx).

Marcello

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