Re: [xml] IO callbacks are not thread-safe

[Petr Pajas <pajas ufal mff cuni cz>]

On po 6. dubna 2009, Nick Wellnhofer wrote:
> Daniel Veillard wrote:
> > On Thu, Apr 02, 2009 at 05:33:54PM +0200, Petr Pajas wrote:
> >> I think the original reason for this was that when Perl
> >> bindings are used with mod_perl, there may be other (non-Perl)
> >> components using the global callbacks differently; that's why
> >> XML::LibXML Perl module tries to clean after itself (restoring
> >> whatever was in the callbacks previously). Is there any other
> >> way around this?
> >
> >   Urgh ..
> > Why do they need global URI handler registration ?
> > The cleanest wey would be to always use the I/O parser context
> > creation routine like xmlCtxtReadIO/xmlReadIO... and define the
> > I/O handlers to map to whatever is being registered globally
> > now. Though the limitation is for external subset resources,
> > that doesn't work well.
>
> Yes, this wouldn't work for things like imported XSLT stylesheets
> or documents loaded with the XSLT document() function.
>
> > Maybe we need to make those per-thread but this is getting ugly
> > !
>
> For me personally, it would be OK if the Perl bindings had an
> option to not touch the callbacks at all. We wouldn't need any
> changes on the libxml side then. Only a caveat on this page would
> be nice: http://xmlsoft.org/threads.html

Ok, I'll add a flag for that in the next version of XML::LibXML,

-- Petr