Re: [xml] 2Bugs in xmlTextReaderExpand()

[Daniel Veillard <veillard redhat com>]

On Wed, Jul 16, 2003 at 11:36:46PM +0200, Berlinez Oussorov fhtw-berlin de wrote:
> Hallo
>
> I use libxml2.5.8 and in xmlTextReaderExpand() Function
> is 2 bugs. The pruduced Node with the subtree contains more Nodes
> then the subtree should. If i print rekursiv all Subtree-Nodes 
> with
> children and next - elements i can see this. 

  Your code is very hard to read.

> ...
> name = xmlTextReaderLocalName(reader);
>     if(name != NULL){
>         if (strcmp(name,"bvclsadr")==0){


  this is not sufficient test, you may visit element nodes twice,
check the documentation and the type too.

>              node = xmlTextReaderExpand(reader);
>              verarbeite(node);           /*Print nodes rekursive 
> hier*/

  this also print the next siblings and their subtree hence the problem

>              ret = xmlTextReaderNext(reader);
>         }
> ...
>
>     void
> verarbeite( node )
>     xmlNodePtr node;
> {
>     xmlChar *name=NULL;
>     xmlChar *value=NULL;
>     xmlChar *content=NULL;
>
>     if(node != NULL){
>     /*For this Node print all children and next Nodes*/
>         if(node->type == XML_ELEMENT_NODE){
>             printf("<%s>",node->name);
>         }
>         if(node->type == XML_TEXT_NODE){
>             if((value = node->content) != NULL){
>                 printf("%s",po_strdelbtn(value)); /*a trim() 
> - Function*/

   if this really does a trim (i.e. both side of the string),
then po_strdelbtn has to leak or not be thread safe, looks poor...

>             }
>         }
>
>         /*all Child Nodes rekursive*/
>         if(node->children!=NULL){
>             if(node->children->type==XML_ELEMENT_NODE){
>                 printf("\n\t");
>             }
>             verarbeite(node->children);
>         }
>         if(node->type == XML_ELEMENT_NODE){
>             printf("</%s>",node->name);
>         }
>         /*all Next Elemente rekursive*/
>         if(node->next!=NULL){
>             if(node->next->type==XML_ELEMENT_NODE){
>                 printf("\n\t");
>             }
>             verarbeite(node->next);

 This also print the siblings of the returned node, no garantee
is provided by Expand, all you know is that the subtree of the given
node is expanded, that's all.

> xmlTextReaderRead() call...Nr:2
> <bvclsadr>
>         <BOVACSA>00001</BOVACSA>
>         <LANR>nr2001</LANR>
>         <ANRED>Herr</ANRED>
>         <VSAD1>Name1</VSAD1>
>         <VSAD2>Name2</VSAD2>
>         <VSAD3>Name3</VSAD3></bvclsadr>
>         <bvclsadr>
>         <BOVACSA>00002</BOVACSA>
>         <LANR>nr2002</LANR>
>         <ANRED>Herr</ANRED>
>         <VSAD1>Name1</VSAD1>
>         <VSAD2>Name2</VSAD2>
>         <VSAD3>Name3</VSAD3></bvclsadr>
>         <bvclsadr>
>         <BOVACSA>00003</BOVACSA>
>         <LANR></LANR></bvclsadr>

  Normal, the chunk processed was more than the first bvclsadr

> xmlTextReaderRead() call...Nr:4
> <bvclsadr>
>         <BOVACSA>00003</BOVACSA>
>         <LANR></LANR></bvclsadr>
> xmlTextReaderRead() call...Nr:5
>
> xmlTextReaderRead() call...Nr:6
>
> As you see at output between Reader() calls 4 and 5 
> the Expand Function has build invalid Tree. That is
> the second bug. Sometimes Expand - Function produces
> invalid Node.

  I'm not sure about this, you don't even give the full code, I can't
see if you stop on <bvclsadr/> too and not just <bvclsadr>.
Provide a complete small python example using the serialize() call
for dumping instead of your own routine and I will check what's happening
really.

Daniel

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