RE: [xml] Feature request: callbacks

["Alfred Reibenschuh" <alfred reibenschu chello at>]

> -----Original Message-----
> From: Daniel Veillard [mailto:veillard redhat com]
> Subject: Re: [xml] Feature request: callbacks
> 
> 
> On Thu, Mar 15, 2001 at 11:02:04AM +0100, Alfred Reibenschuh wrote:
> > hi!
> > 
> > adding callback for tree-changes seams to be a good thing to do,
> > but then with a more global approach -- having callbacks for
> > creation, change and deletion of nodes globally per tree
> > and change and deletion callbacks per node.
> 
>   yes, that's what I was thinking. Except I don't perceive the difference
> you make w.r.t. per node or per tree. Could you elaborate ?

ahmm ... robert pointed that out in his email ... let me sum it up as i see this: 

having a callback structure at node, document and application-level like:

struct {
	int xmlCallbackStackLevel;
	void * xmlTreeChangeCallbackStack[];
}

whereas the first pointer registered in xmlTreeChangeCallbackStack at node-level
would be the callback-handler for the document-level and the first pointer registered 
at document-level would be the callback-handler for the application-level
and the first pointer registered at application-level would be libxml's own handler
or NULL whichever is preferable

if a node is changed/deleted/.... the callbacks are called in descending order
on the node, the first callback of the node then calls all the document-callbacks
etc, etc ...

>   - Callback signature:
>     a few week ago I would have used
>     void (*xmlTreeChangeCallback) (xmlNodePtr node);
>     but it's clear that Perl binding would require something like
>     void (*xmlTreeChangeCallback) (void *user_data, xmlNodePtr node);
>     is that sufficient ? I assume user_data would be registered at
>     the same time as the set of callbacks.

definitely "void (*xmlTreeChangeCallback) (void *user_data, xmlNodePtr node)",
since that seems to me just what perl and php need :) 


> > ( users should then be required to call the change-callback  
> >   on the completion of a change to a node )
> 
>   Hum, that is application dependant ... what I want to define
> is the library behaviour and not step on the toes of the application
> writer.

just forget it then ...


> <shame>
>   Euro's one or dollar's ?
> </shame>

<pride type="assuring" lang="de_AT">
	it's the &Euro; one :)
</pride>

 

-- Alfred Reibenschuh

(Khelben Blackstaff)

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