Re: [PATCH] Add pretty-printed XML output option

On Thu, Feb 9, 2023 at 10:42 AM Jim Jones <jim.jones@uni-muenster.de> wrote:
>
> On 09.02.23 00:09, Peter Smith wrote:
> > I noticed the xmlFreeDoc(doc) within the PG_CATCH is guarded but the
> > other xmlFreeDoc(doc) is not. As the doc is assigned outside the
> > PG_TRY shouldn't those both be the same?
>
> Hi Peter,
>
> My logic there was the following: if program reached that part of the
> code it means that the xml_parse() and xmlDocDumpFormatMemory() worked,
> which consequently means that the variables doc and xmlbuf are != NULL,
> therefore not needing to be checked. Am I missing something?
>

Thanks. I think I understand it better now -- I expect
xmlDocDumpFormatMemory will cope OK when passed a NULL doc (see this
source [1]), but it will return nbytes of 0, but your code will still
throw ERROR, meaning the guard for doc NULL is necessary for the
PG_CATCH.

In that case, everything LGTM.

~

OTOH, if you are having to check for NULL doc anyway, maybe it's just
as easy only doing that up-front. Then you could quick-exit the
function without calling xmlDocDumpFormatMemory etc. in the first
place. For example:

doc = xml_parse(arg, XMLOPTION_DOCUMENT, false, GetDatabaseEncoding(), NULL);
if (!doc)
   return 0;

------
Kind Regards,
Peter Smith.
Fujitsu Australia.