[xml] xmlwriter, attributes and encoding

[Rob Richards <rrichards ctindustries net>]

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).

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 11 Aug 2006 20:02:29 -0000
***************
*** 1425,1432 ****
                      break;
                  case XML_TEXTWRITER_ATTRIBUTE:
                      buf = NULL;
!                     xmlAttrSerializeTxtContent(writer->out->buffer, NULL,
!                                                NULL, content);
                      break;
                default:
                    break;
--- 1425,1441 ----
                      break;
                  case XML_TEXTWRITER_ATTRIBUTE:
                      buf = NULL;
!                                       
!                     if (writer->out->encoder) {
!                         xmlDoc doc;
!                         memset(&doc, 0, sizeof(xmlDoc));
!                         doc.encoding = (xmlChar *)writer->out->encoder->name;
!                         xmlAttrSerializeTxtContent(writer->out->buffer, &doc,
!                                                    NULL, content);
!                     } else {
!                         xmlAttrSerializeTxtContent(writer->out->buffer, NULL,
!                                                    NULL, content);
!                     }
                      break;
                default:
                    break;