[xml] libxml memory problem.....

[Matt White <matt white albertsons com>]

I've been working on a project using libxml2-2.2.7 (which was current at the
time my project began (I'm running it on two different platforms: Solaris
2.7 x86 and AT&T SVR4 3.02).

I've been using the xmlmemory functions to try and chase down a memory leak
and I've mocked up some code to reproduce what I've been seeing.  After
constructing a DOM with a SOAP envelope I added a single node and then copy
the entire contents of the DOM to a buffer using xmlDocDumpMemory, then I
release the DOM with xmlFreeDoc.  

The problem here in the example code is that xmlMemUsed still reports 224
bytes of memory allocated after the xmlFreeDoc function was called.  I would
have expected the amount used to be 0 after the xmlFreeDoc?  If I run this
code in a loop the 224 bytes increment with each iteration through the code.
The culprit seems to xmlDocDumpMemory, but I've also seen similar behavior
out of xmlSetProp, and others.

#include <stdio.h>
#include <libxml/tree.h>
#include <libxml/parser.h>
#include <libghttp/ghttp.h>
#include <libghttp/ghttp_constants.h>

#define XML_SOAP_ENVELOPE_URL "http://schemas.xmlsoap.org/soap/envelope/";
#define XML_SOAP_ENCODING_URL "http://schemas.xmlsoap.org/soap/encoding/";

#define DEBUG_MEMORY
#define MEM_LIST

int main(void)
{
   xmlDocPtr  doc;
   xmlNodePtr tree, subtree;
   xmlNsPtr   ns;
   xmlChar    *buf;
   int        len;

   xmlInitMemory();
   doc = xmlNewDoc(XML_DEFAULT_VERSION);
        
   printf("xmlMemUsed at start = %d\n", xmlMemUsed());

   doc->children = xmlNewDocNode(doc, NULL, "SOAP:Envelope", NULL);
   ns = xmlNewNs(doc->children, XML_SOAP_ENVELOPE_URL, "SOAP");
   xmlNewNsProp(doc->children, ns, "encodingStyle", XML_SOAP_ENCODING_URL);
   subtree = xmlNewChild(doc->children, NULL, "SOAP:Body", NULL);
   tree = xmlNewChild(subtree, NULL, "foobar", "content");

   xmlDocDumpMemory(doc, &buf, &len);
   printf("buf[%d]=\n%s\n", len, buf);
   free(*buf);

   xmlCleanupParser();
   xmlFreeDoc(doc);

   printf("xmlMemUsed at end = %d : is this amount leaked ?\n",
xmlMemUsed());
   xmlMemoryDump();
   return(0);
}
 

# ./xmltest
xmlMemUsed at start = 84
buf[208]=
<?xml version="1.0"?>
<SOAP:Envelope xmlns:SOAP="http://schemas.xmlsoap.org/soap/envelope/";
SOAP:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/";>
<SOAP:Body>
<foobar/>
</SOAP:Body>
</SOAP:Envelope>

xmlMemUsed at end = 224 bytes : is this amount of memory leaked ?

# cat .memdump
      Mon Sep 24 01:09:00 2001

      MEMORY ALLOCATED : 224, MAX was 5614
BLOCK  NUMBER   SIZE  TYPE
0          26    224 malloc()  in parser.c(939) [<?xml version="1.0"?>]


I sure I must be doing something wrong here I'm just not sure what it is.
Could someone point me in the right direction?

Any help would be greatly appreciated,

-Matt