Re: nsGenericElement::InsertBefore performance

Andreas Pflug wrote:
> Initialisation will still be several magnitudes faster, since all 
> controls will use their readily compiled handlers.

Of course XBL also uses precompiled handlers...  The real issue here is not the 
handlers.

> I see the problem that XUL/XBL is used as if it was as cheap as it is 
> with typical gui lib

Putting 8 images in a dialog is cheap with a typical GUI lib?

 > XUL/XBL is intended to do typical application programming (I think?)

Yes.

> but using typical programming 
> techniques will lead to poor results (unfortunately demonstrated by 
> Sunbird/Lightning, which appears as some kind of Mozilla demo app to me 
> since it's integrated into the mozilla source tree).

Uh... That's a really really bad assumption.  _Really_ bad.

My basic point was that the code involved is just poorly written if one is at 
all interested in performance.

>> Caching what, exactly?
>>   
> A partial DOM. So instead of adding a bunch of nodes (which all need a 
> lot of basic initialisation), in a first step a partial tree of those 
> nodes is instantiated, not attached to the DOM (although probably 
> somewhat "prepared" for a specific document)

XBL is shared across documents (and designed to be so), so this is actually not 
that useful.

> and held in a caching  area. Then when adding the xxxx-item a "cache using" node that will be 
> added to the DOM, consisting of a reference to the cached node tree, and 
> some individual data (e.g. label text).

You just described the XUL prototype system.  Which XBL uses, in fact, when 
cloning the subtree, if the subtree is XUL.

> Easy, no? ;-)

Not easy, but done!  ;)

> Actually, I don't quite understand your comment above. Do you say that 
> it's quite a lot of XBL-bound DOM stuff (that should be reduced)

Yes.

> but it will only be cloned if attached again and again? In this case, cloning 
> seems a) still much too costly and could b) be optimized if the partial 
> item's DOM isn't cloned (each cal-mon-day-item uses about 20k) but only 
> references a "template" DOM.

See above.  Cloning XUL produces lightweight XUL elements that point to the 
prototype element...  It's already optimized for exactly this use case.

-Boris