I'll re-iterate, as long as you use "official" LibXML2 API, it should
work just fine. Or there is a bug in the LibXML2 code :)
Aleksey
On 3/21/14, 1:06 AM, Frank Gross wrote:
> Ok, I understand the need of speed, but there is still something that
> worries me. This means that the Canonicalization process depends then on
> the way the XML document is in memory. For instance, if I load a XML
> document from disk and canonicalize it, or build the same document in
> memory from scratch with node built maybe from copy or clone of another
> document in memory, the Canonicalization result can be different, even
> if document saved on disk would be the same.
>
> But ok, I will fix it in my code
>
> Thanks a lot,
> Frank
>
>
> Le 20/03/2014 15:04, Aleksey Sanin a écrit :
>> The tradeoff here is speed. Again, if you are using standard LibXML2
>> API then everything will work as expected. I have no idea why do you
>> need to create new xmlNsPtr objects - this sounds like a waste of
>> CPU/memory to me but you might have your reasons. But this also breaks
>> a few assumptions on how LibXML2 represents the DOM tree in memory
>> and you are on your own in this case.
>>
>> Aleksey
>>
>> On 3/20/14, 1:26 AM, Frank Gross wrote:
>>> Hi,
>>>
>>> Actually, I have an additional layer to emulate DOM compliant API over
>>> libxml. In that layer, I have a global list of xmlNsPtr for all
>>> namespaces encountered by the nodes (and referenced in node->ns) of a
>>> single XML document. And for each namespace definition (xmlns:xxx) set
>>> on a node, a new xmlNsPtr is created and referenced in node->nsDef. So
>>> during canonicalization process, when a node looks for a parent
>>> namespace definition via xmlSearchNs, it can happen that the xmlNsPtr
>>> reference from the node is different from the parent node->nsDef , even
>>> if the href and prefix value are the same. Then of course simple pointer
>>> comparison doesn't work. So I was asking myself if such situation cannot
>>> happen to other people, and maybe change the pointer comparison because
>>> depending on how people build and manipulate the document, the test is
>>> not always accurate.
>>>
>>>
>>> Frank
>>>
>>>
>>> Le 20/03/2014 03:16, Aleksey Sanin a écrit :
>>>> How do you manipulate the XML tree? If you are using "official" LibXML2
>>>> function then I believe this code should work just fine unless there is
>>>> a bug in the strings dictionary.
>>>>
>>>> Aleksey
>>>>
>>>> On 3/12/14, 10:28 AM, Frank Gross wrote:
>>>>> Hi,
>>>>>
>>>>> I'm getting some trouble to verify a XML signature because the
>>>>> xmlC14NProcessNamespacesAxis() function does a xmlNsPtr pointer
>>>>> comparison to decide whether a sub node belongs to the same default
>>>>> namespace as an ancestor. But if the sub node has been manipulated by
>>>>> program (in my case) to point to another xmlNsPtr with same values,
>>>>> the
>>>>> canonicalization process breaks. Wouldn't it be better to check the
>>>>> namespace href values instead as in following patch ?
>>>>>
>>>>> diff --git a/lib-xmlsoft-libxml2/src/c14n.c
>>>>> b/lib-xmlsoft-libxml2/src/c14n.c
>>>>> index 9c3cad2..f73e709 100644
>>>>> --- a/lib-xmlsoft-libxml2/src/c14n.c
>>>>> +++ b/lib-xmlsoft-libxml2/src/c14n.c
>>>>> @@ -623,7 +623,7 @@ xmlC14NProcessNamespacesAxis(xmlC14NCtxPtr ctx,
>>>>> xmlNodePtr cur, int visible)
>>>>> for(ns = n->nsDef; ns != NULL; ns = ns->next) {
>>>>> tmp = xmlSearchNs(cur->doc, cur, ns->prefix);
>>>>>
>>>>> - if((tmp == ns) && !xmlC14NIsXmlNs(ns) &&
>>>>> xmlC14NIsVisible(ctx,
>>>>> ns, cur)) {
>>>>> + if((xmlStrEqual(tmp->href,ns->href)) &&
>>>>> (xmlStrEqual(tmp->prefix,ns->prefix)) && !xmlC14NIsXmlNs(ns) &&
>>>>> xmlC14NIsVisible(ctx, ns, cur)) {
>>>>> already_rendered =
>>>>> xmlC14NVisibleNsStackFind(ctx->ns_rendered,
>>>>> ns);
>>>>> if(visible) {
>>>>> xmlC14NVisibleNsStackAdd(ctx->ns_rendered, ns,
>>>>> cur);
>>>>>
>>>>> Regards,
>>>>> Frank
>>>>>
>
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