[libvirt] [PATCH 2/2] xml: Surpress printing "domain.xml" for parse errors on XML strings

[Eric Blake]

On 08/16/2011 06:49 AM, Peter Krempa wrote:
> Patch a53ab1094e93f1b6d93ad9be63d8ccc5fd19a2a9 introduces printing
> file name on XML errors. This corrects the URL string to be NULL and
> therefrore to print an error message not containing bogus filename

s/therefrore/therefore/

> "domain.xml".
> ---
>   src/conf/domain_conf.c        |    2 +-
>   src/security/virt-aa-helper.c |    2 +-
>   2 files changed, 2 insertions(+), 2 deletions(-)

> +++ b/src/conf/domain_conf.c
> @@ -7048,7 +7048,7 @@ virDomainDefParse(const char *xmlStr,
>       xmlDocPtr xml;
>       virDomainDefPtr def = NULL;
>
> -    if ((xml = virXMLParse(filename, xmlStr, "domain.xml"))) {
> +    if ((xml = virXMLParse(filename, xmlStr, NULL))) {

I'm not sure I follow the difference between filename and url arguments. 
  In virXMLParseHelper, this is resulting in the difference between 
xmlCtxtReadFile(pctxt, filename, NULL, flags) and xmlCtxtReadDoc(pctxt, 
string, url, NULL, flags).  If I'm understanding correctly, that means 
that 'url' is treated as the filename owning the string being parsed 
(that is, if you had manually read the file contents yourself and pass 
the contents as a string, instead of caling xmlCtxtReadFile directly, 
then you would use the filename of xmlCtxtReadFile as the url of 
xmlCtxtReadDoc).

I guess passing NULL as the url is okay - it just means that any errors 
reported by the parser are no longer tied to a specific filename (which 
is okay, because we are intercepting the error reporting, and reporting 
it on behalf of just the string line number anyway).

I wonder if this patch is complete, or if there are more instances where 
we are passing a url to xml parse functions even though the string was 
generated rather than being tied to a real file.  tools/virsh.c in 
particular may need some cleanups related to this, although I don't see 
it using virXMLParse.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org