[Expat-discuss] Exiting expat handlers

[Fred L. Drake, Jr.]

Ken Johnston writes:
 > I would be very interested in finding out about option b). Is there any
 > way in ANSI C (not C++) for a handler which detects an application error
 > to cause XML_Parse to abort parsing and return immediately to the caller
 > (of XML_Parse)? It doesn't have to return with an error or clean up the
 > parse object. That could all be flagged in the user data from the
 > handler that found the error.

I'm afraid the support for this isn't very good in the current API.
What I do for the Python bindings is, if an exception is raised by
Python, remove all the callbacks (which avoids some overhead, but not
the actual parsing), and installs a special handler for the external
entity reference handler that simply reports that an error has
occurred (CVS version of PyXML only, for any Python users out there).

The setjmp/longjmp approach, described by someone else on the list,
can certainly work, but can cause problems for long-running processes
that keep lots of objects on the heap but maintain lifetime
information on the stack, so you need to be careful with that
approach.

We are planning to improve this situation in a future release, but
haven't had time to work on it recently.


  -Fred

-- 
Fred L. Drake, Jr.  <fdrake at acm.org>
PythonLabs at Zope Corporation