Re: [xml] Relaxng memory discipline (Python bindings)

[Daniel Veillard <veillard redhat com>]

On Wed, Aug 13, 2003 at 11:39:23PM -0400, Anthony Carrico wrote:
> I'm trying to figure out the relaxng memory discipline under Python
> bindings.
>
> 1. Whereas xmlNode uses manual free with xmlNode.freeNode(), the
> relaxNgParserCtxt seems to rely on the garbage collector's __del__
> callback. It seems like manual free is also possible using
> relaxNgParserCtxt.relaxNGFreeParserCtxt. Is it fine to use this manual
> free? Shouldn't relaxNGFreeParserCtxt set self._o to None to prevent
> __del__ from calling xmlRelaxNGFreeParserCtxt twice?
>
> 2. Same issue for relaxNgSchema.
>
> 3. Same issue for relaxNgValidCtxt.
>
> 4. Is it ok to free the relaxNgParserCtxt before the relaxNgSchema
> (and keep using the relaxNgSchema)?
>
> 5. Is it ok to free the relaxNgSchema before the relaxNgValidCtxt (and
> keep using the relaxNgValidCtxt)?
>
> 6. How does libxml2.relaxNGCleanupTypes() fit in? Does this just clean
> up some global state that is automatically created anytime you use one
> of the relaxNg procedures?

  Have you read http://xmlsoft.org/python.html ? That sounds like a good start.
------------------------------
Also note the need to explicitly deallocate documents with freeDoc()
. Reference counting for libxml2 trees would need quite a lot of work to
function properly, and rather than risk memory leaks if not implemented
correctly it sounds safer to have an explicit function to free a tree. The
wrapper python objects like doc, root or child are them automatically
garbage collected.
------------------------------

  Document tree cannot be garbage collected by python. All wrapper objects
GC'ed, all objects which do not pertain to a tree are too. And the reader
doesn not build a tree... Reading the examples helps too they explicitely
check for memory leaks.

Daniel

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