Re: [xml] Identifying the source file for an xi inclusion

On Fri, 2009-02-20 at 19:14 +0100, Daniel Veillard wrote:
On Fri, Feb 13, 2009 at 12:23:09PM -0800, Marc Munro wrote:
On Sat, 2009-01-31 at 08:12 +0100, Daniel Veillard wrote:
On Thu, Jan 29, 2009 at 01:50:52PM -0800, Marc Munro wrote:
I am processing a document which contains nested inclusions using
xi:include.  How can I tell the source file from which a given node was
included into the document?

  Not always possible, for example if you XInclude a text node, well
there is little to help. But you can use 2 things:
  xml:base attribute left by the xinclude process, if you ask for the
    base at a given included point, you may get the proper URI
    if there was room left to put the base attribute at the inclusion
    point (i.e. on an element)
  the XInclude process also turns the original xi:include element into
    an XML_XINCLUDE_START node with all attributes left and also add
    an XML_XINCLUDE_END after the included element(s)

I thought I'd try figuring out the URI the hard way and so traversed to
the XML_XINCLUDE_START node for the inclusion.  I was hoping to find the
href attribute saved there but instead find no attributes at all.

  The XML_XINCLUDE_START node is really the old xi:xinclude node just
changed to be of the new type, really all informations should be there,
though the attribute reading API may not work because the node type
is not XML_ELEMENT_NODE ... check directly the ->properties list.

Daniel, thanks for the response.  Using gdb I have confirmed that the
XML_XINCLUDE_START for the nested inclusion has no properties (gdb
session pasted below).  The node for the outermost inclusion does have
the expected properties, and does provide the href attribute.

The gdb session follows.  The breakpoint is set within my exception
handler where prev is an XmlNode * pointing to the XML_XINCLUDE_START
node.  As you will see the first breakpoint, within the inner nested
inclusion, yields a node where there are no properties.  The second, for
the outermost inclusion, shows the expected properties.
-----gdb session--------------------------------
(gdb) break src/xmlfile.c:1062
Breakpoint 1 at 0x805f187: file src/xmlfile.c, line 1062.
(gdb) run -n params extract
Starting program: /home/marc/proj/skit2/skit_test -n params extract
[Thread debugging using libthread_db enabled]
Running suite(s): 
[New Thread 0xb7683a00 (LWP 8876)]
XX: include
XX: dump
XX: runsql
XX: stylesheet
XX: (null)
DEBUG PRIVNAMES: <('C' . 'create') ('T' . 'temporary') ('U' . 'usage') ('X' . 'execute') ('a' . 'insert') 
('c' . 'connect') ('d' . 'delete') ('r' . 'select') ('t' . 'trigger') ('w' . 'update') ('x' . 'references')>
XX: exception
XX: inclusion
[Switching to Thread 0xb7683a00 (LWP 8876)]

Breakpoint 1, getNodeURI (node=0x9291f88) at src/xmlfile.c:1062
(gdb) p *prev
$1 = {_private = 0x0, type = XML_XINCLUDE_START, name = 0x926f3b0 "include", children = 0x0, last = 0x0, 
parent = 0x9292698, next = 0x9291f88, prev = 0x9291ed8, doc = 0x926f6c8, ns = 0x9289050, content = 0x0, 
properties = 0x0, nsDef = 0x0, psvi = 0x0, line = 0, extra = 0}
(gdb) c
XX: runsql
XX: let
XX: cluster
XX: inclusion

Breakpoint 1, getNodeURI (node=0x9292c00) at src/xmlfile.c:1062
(gdb) p *prev
$2 = {_private = 0x0, type = XML_XINCLUDE_START, name = 0x926f3b0 "include", children = 0x0, last = 0x0, 
parent = 0x92720e8, next = 0x9292c00, prev = 0x9272be8, doc = 0x926f6c8, ns = 0x926f8a8, content = 0x0, 
properties = 0x9272d48, nsDef = 0x0, psvi = 0x0, line = 33, extra = 7}
(gdb) p nodeAttribute(prev, "href")
$3 = (String *) 0x0
(gdb) p node->properties
$4 = (struct _xmlAttr *) 0x9297760
(gdb) p *node->properties
$5 = {_private = 0x0, type = XML_ATTRIBUTE_NODE, name = 0x926f491 "base", children = 0x9297798, last = 
0x9297798, parent = 0x9292c00, next = 0x0, prev = 0x0, doc = 0x926f6c8, ns = 0x9297708, atype = 0, psvi = 0x0}
(gdb) p *node->properties->children
$6 = {_private = 0x0, type = XML_TEXT_NODE, name = 0xb7ed55d8 "text", children = 0x0, last = 0x0, parent = 
0x9297760, next = 0x0, prev = 0x0, doc = 0x926f6c8, ns = 0x0, content = 0x92977d8 
"skitfile:extract/cluster.xml", properties = 0x0, nsDef = 0x0, psvi = 0x0, line = 0, extra = 0}
-----gdb session--------------------------------

Code called from the node at which an exception is raised, to find the

-----source code--------------------------------
static xmlChar *
getNodeURI(xmlNode *node)
    xmlNode *prev;
    xmlChar *contents;
    xmlChar *name;
    String *href;
    while (node) {
        fprintf(stderr, "XX: %s\n", nodeName(node));
        name = nodeName(node);
        if (name && streq(name, "inclusion")) {
            prev = node->prev;
            if (prev->type == XML_XINCLUDE_START) {
                fprintf(stderr, "HERE\n");
                xmlDebugDumpOneNode(stderr, prev, 1);
                if (href = nodeAttribute(prev, "href")) {
                    printSexp(stderr, "INCLUSION: ", (Object *) href);
                    objectFree((Object *) href, TRUE);
        node = node->parent;
    return NULL;
-----source code--------------------------------

I am happy to try to track this down if you can offer suggestions.
FWIW, I don't think this is the result of random memory corruption as
valgrind reports no issues.


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