Re: [xml] Support for Python

[Matt Sergeant <matt sergeant org>]

On Mon, 28 Jan 2002, Daniel Veillard wrote:

> > > If we write the classes in Python then this is trivial -- call xmlFreeDoc
> > > in the XmlDocumentClass's destructor and let Python's garbage collector
> > > work out when to do it.
> >
> > Interesting idea.  Because of your suggestion, I looked at the
> > generated code.  And, I can modify the SWIG generated code so that
> > the Python __del__ method in the Doc class will call a C delete
> > method and I can modify the C delete method so that it calls
> > xmlFreeDoc.
>
>   Really dangerous. As you pointed out too as soon as Python will loose
> a pointer to the root it would then deallocate the full subtree. Too
> dangerous to be allowed. I started toying with the idea but as soon
> as I tried to build an example I realized it would really make a big problem.
>   I don't think we can have garbage collectable xmlDoc, though nearly
> every other classes exposed should be garbageable.

We do this with a proxy object in the Perl interface - the proxy simply
makes sure that the refcount doesn't get lost, and then DESTROY
(equivalent of __del__) does the xmlFree stuff. Works mostly quite well,
though it's a bit tricky to debug.

-- 
<!-- Matt -->
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