Re: [xml] xmlwriter, attributes and encoding

[Rob Richards <rrichards ctindustries net>]

Daniel Veillard wrote:
> On Tue, Aug 15, 2006 at 07:06:48PM -0400, Rob Richards wrote:
>   
> > When using xmlwriter attributes , document encoding that has been set is 
> > not passed to xmlAttrSerializeTxtContent, so character references are 
> > written when needed.
> > The xmlDocPtr passed to xmlAttrSerializeTxtContent is only used to check 
> > encoding, so I was wondering if the code in the attached patch is fine 
> > to fix this (it fakes a document so any changes within 
> > xmlAttrSerializeTxtContent to manipulate the passed document could 
> > possibly blow up - though i dont see any need/reason to ever do this).
> >     
>
>   Hum, that's a bit nasty, because none of the fields in the document
> structure are initialized (except encoding), so it internally use an
> API based not on the API description but on its implementation. If at
> some point someone add something like entity lookup to
> xmlAttrSerializeTxtContent or just check the document type, suddently
> the writer would crash in an unexpected way. 
>   So fields should at least be zero initialized, which is probably
> a bit costly if done for every single attribute emitted. So while passing
> a document might be a good idea, it's better to create and initialize that
> document when getting the xmlTextWriterPtr. Maybe adding a doc in 
> struct _xmlTextWriter and making sure it's at least minimally initialized
> and properly freed with the xmlTextWriter is a good idea. That sounds
> far more clean to me, but a bit more work indeed :-)
>
> Daniel
>   

Was tying to keep the change as minimal as possible, so how about this one.
A doc has been added to the struct and is always created within 
xmlNewTextWriter(). This would at least provide a doc that could be used 
for this type of thing, rather than checking if one exists and having to 
create one if needed at different points within the xmlwriter API. This 
doc is also completely independent of any doc that may exist within a 
context.

Rob

Index: xmlwriter.c
===================================================================
RCS file: /cvs/gnome/gnome-xml/xmlwriter.c,v
retrieving revision 1.36
diff -c -r1.36 xmlwriter.c
*** xmlwriter.c 27 Apr 2006 08:10:25 -0000      1.36
--- xmlwriter.c 16 Aug 2006 10:14:40 -0000
***************
*** 91,96 ****
--- 91,97 ----
      char qchar;                 /* character used for quoting attribute values */
      xmlParserCtxtPtr ctxt;
      int no_doc_free;
+       xmlDocPtr doc;
  };
  
  static void xmlFreeTextWriterStackEntry(xmlLinkPtr lk);
***************
*** 215,220 ****
--- 216,224 ----
                          "xmlNewTextWriter : out of memory!\n");
          return NULL;
      }
+ 
+       ret->doc = xmlNewDoc(NULL);
+ 
      ret->no_doc_free = 0;
  
      return ret;
***************
*** 487,492 ****
--- 491,499 ----
          xmlFreeParserCtxt(writer->ctxt);
      }
  
+       if (writer->doc != NULL)
+               xmlFreeDoc(writer->doc);
+ 
      if (writer->ichar != NULL)
          xmlFree(writer->ichar);
      xmlFree(writer);
***************
*** 539,544 ****
--- 546,553 ----
      if (encoder != NULL) {
          writer->out->conv = xmlBufferCreateSize(4000);
          xmlCharEncOutFunc(encoder, writer->out->conv, NULL);
+               if (writer->doc)
+                       writer->doc->encoding = xmlStrdup((xmlChar *)writer->out->encoder->name);
      } else
          writer->out->conv = NULL;
  
***************
*** 1425,1432 ****
                      break;
                  case XML_TEXTWRITER_ATTRIBUTE:
                      buf = NULL;
!                     xmlAttrSerializeTxtContent(writer->out->buffer, NULL,
!                                                NULL, content);
                      break;
                default:
                    break;
--- 1434,1441 ----
                      break;
                  case XML_TEXTWRITER_ATTRIBUTE:
                      buf = NULL;
!                     xmlAttrSerializeTxtContent(writer->out->buffer, writer->doc,
!                                                    NULL, content);
                      break;
                default:
                    break;