Re: [xml] xmlschemas.c patch

[Steve Ball <Steve Ball zveno com>]

Hi Daniel,

On 19/01/2004, at 9:05, Daniel Veillard wrote:
> On Mon, Jan 19, 2004 at 07:08:30AM +1100, Steve Ball wrote:
> > Found a bug in xmlschemas.c last week, a small patch is attached.
>    Hum, thanks but I think both were fixed in CVS some time ago.

One of the bugs, initialising the dictionary, has been fixed, but there
remains the second bug.

> > This fixes two problems when compiling a XML Schema from an in-memory
> > xmlDocPtr structure.  The document is copied from the parser context
> > and the dictionary is initialised.
>
>  I'm very dubious about the xmlCopyDoc(ctxt->doc, 1) sounds like
>  a giant memory leak. Can you check the CVs version and see if your 
> problem
> is fixed instead ?

The xmlSchemaParserCtxt as well as the xmlSchema both assume that
they have a copy of the schema document.  xmlSchemaFreeParserCtxt and
xmlSchemaFree both execute xmlFreeDoc, hence the current code will
free the document twice.

xmlSchemaParse modifies its copy of the document,  so it really does 
need its own
copy of the document.

I can see the following alternatives:

1. xmlSchemaParserCtxt must copy the document, which will consume 
additional memory.
This also means that subsequent changes to the document will not be 
seen if the same parser
context is used to create another compiled schema.

2. Set ctxt->doc = NULL after copying the document in xmlSchemaParse.  
This would make
the parser context non-reusable.

3. Don't have xmlSchemaFreeParserCtxt free the document.  It is up to 
the application
to free the document.

Now that I've looked into it alot further I see no reason why 
xmlSchemaFreeParserCtxt
should free the document.

Your thoughts?

Cheers,
Steve Ball


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