plugged the extension of the engine with python defined functions added a

* python/libxlst.c python/libxslt-python-api.xml
  python/libxsltclass.txt: plugged the extension of the engine
  with python defined functions
* python/tests/Makefile.am python/tests/extfunc.py: added a
  basic test, still a memleak, cleanup function needed.
Daniel

python/libxslt-python-api.xml

@@ -12,6 +12,13 @@
       <arg name='doc' type='xmlDocPtr' info='a parsed XML document'/>
       <arg name='params' type='pythonObject' info='the parameters dictionnary'/>
     </function>
+    <function name='xsltRegisterExtModuleFunction' file='python'>
+      <info>Register a Python written function to the XSLT engine</info>
+      <return type='int' info="0 in case of success, -1 in case of error"/>
+      <arg name='name' type='xmlChar *' info='the function name'/>
+      <arg name='URI' type='xmlChar *' info='the namespace or NULL'/>
+      <arg name='f' type='pythonObject' info='the python function'/>
+    </function>
   <!--
     <function name='xsltRegisterXPathFunction' file='python'>
       <info>Register a Python written function to the XPath interpreter</info>

python/libxslt.c

@@ -141,6 +141,99 @@ libxslt_xmlDumpMemory(PyObject *self, PyObject *args) {
     return(Py_None);
 }
 
+/************************************************************************
+ *									*
+ *			Extending the API				*
+ *									*
+ ************************************************************************/
+
+static xmlHashTablePtr libxslt_extModuleFunctions = NULL;
+
+static void
+libxslt_xmlXPathFuncCallback(xmlXPathParserContextPtr ctxt, int nargs) {
+    PyObject *list, *cur, *result;
+    xmlXPathObjectPtr obj;
+    xmlXPathContextPtr rctxt;
+    PyObject *current_function = NULL;
+    const xmlChar *name;
+    const xmlChar *ns_uri;
+    int i;
+
+    if (ctxt == NULL)
+	return;
+    rctxt = ctxt->context;
+    if (rctxt == NULL)
+	return;
+    name = rctxt->function;
+    ns_uri = rctxt->functionURI;
+#ifdef DEBUG_XPATH
+    printf("libxslt_xmlXPathFuncCallback called name %s URI %s\n", name, ns_uri);
+#endif
+
+    /*
+     * Find the function, it should be there it was there at lookup
+     */
+    current_function = xmlHashLookup2(libxslt_extModuleFunctions,
+	                              name, ns_uri);
+    if (current_function == NULL) {
+	printf("libxslt_xmlXPathFuncCallback: internal error %s not found !\n",
+	       name);
+	return;
+    }
+
+    list = PyTuple_New(nargs);
+    for (i = 0;i < nargs;i++) {
+	obj = valuePop(ctxt);
+	cur = libxml_xmlXPathObjectPtrWrap(obj);
+	PyTuple_SetItem(list, i, cur);
+    }
+    result = PyEval_CallObject(current_function, list);
+    Py_DECREF(list);
+
+    obj = libxml_xmlXPathObjectPtrConvert(result);
+    valuePush(ctxt, obj);
+}
+
+PyObject *
+libxslt_xsltRegisterExtModuleFunction(PyObject *self, PyObject *args) {
+    PyObject *py_retval;
+    int ret = 0;
+    xmlChar *name;
+    xmlChar *ns_uri;
+    PyObject *pyobj_f;
+
+    if (!PyArg_ParseTuple(args, "szO:registerXPathFunction",
+		          &name, &ns_uri, &pyobj_f))
+        return(NULL);
+
+    if ((name == NULL) || (pyobj_f == NULL)) {
+	py_retval = libxml_intWrap(-1);
+	return(py_retval);
+    }
+
+#ifdef DEBUG_XPATH
+    printf("libxslt_xsltRegisterExtModuleFunction(%s, %s) called\n",
+	   name, ns_uri);
+#endif
+
+    if (libxslt_extModuleFunctions == NULL)
+	libxslt_extModuleFunctions = xmlHashCreate(10);
+    if (libxslt_extModuleFunctions == NULL) {
+	py_retval = libxml_intWrap(-1);
+	return(py_retval);
+    }
+    ret = xmlHashAddEntry2(libxslt_extModuleFunctions, name, ns_uri, pyobj_f);
+    if (ret != 0) {
+	py_retval = libxml_intWrap(-1);
+	return(py_retval);
+    }
+
+    ret = xsltRegisterExtModuleFunction(name, ns_uri, 
+	                                     libxslt_xmlXPathFuncCallback);
+    py_retval = libxml_intWrap((int) ret);
+    return(py_retval);
+}
+
 /************************************************************************
  *									*
  *			Some customized front-ends			*
@@ -156,7 +249,7 @@ libxslt_xsltApplyStylesheet(PyObject *self, PyObject *args) {
     xmlDocPtr doc;
     PyObject *pyobj_doc;
     PyObject *pyobj_params;
-    char **params;
+    const char **params;
 
     if (!PyArg_ParseTuple(args, "OOO:xsltApplyStylesheet", &pyobj_style, &pyobj_doc, &pyobj_params))
         return(NULL);

python/libxsltclass.txt

@@ -18,6 +18,9 @@ registerAllExtras()
 # functions from module functions
 registerAllFunctions()
 
+# functions from module python
+registerExtModuleFunction()
+
 # functions from module transform
 setXIncludeDefault()
 xincludeDefault()

python/tests/Makefile.am

@@ -1,7 +1,8 @@
 EXAMPLE_DIR = $(prefix)/share/doc/libxslt-python-$(LIBXML_VERSION)/examples
 
 TESTS=		\
-    basic.py
+    basic.py	\
+    extfunc.py
 
 XMLS=		\
     test.xml	\

python/tests/extfunc.py

@@ -0,0 +1,49 @@
+#!/usr/bin/python -u
+import sys
+import libxml2
+import libxslt
+
+# Memory debug specific
+libxml2.debugMemory(1)
+
+def f(str):
+    import string
+    return string.upper(str)
+
+libxslt.registerExtModuleFunction("foo", "http://example.com/foo", f)
+
+styledoc = libxml2.parseDoc("""
+<xsl:stylesheet version='1.0'
+  xmlns:xsl='http://www.w3.org/1999/XSL/Transform'
+  xmlns:foo='http://example.com/foo'
+  xsl:exclude-result-prefixes='foo'>
+
+  <xsl:template match='/'>
+    <article><xsl:value-of select='foo:foo(\"foo\")'/></article>
+  </xsl:template>
+</xsl:stylesheet>
+""")
+style = libxslt.parseStylesheetDoc(styledoc)
+doc = libxml2.parseDoc("<doc/>")
+result = style.applyStylesheet(doc, None)
+style = None
+doc.freeDoc()
+
+root = result.children
+if root.name != "article":
+    print "Unexpected root node name"
+    sys.exit(1)
+if root.content != "FOO":
+    print "Unexpected root node content, extension function failed"
+    sys.exit(1)
+
+result.freeDoc()
+
+# Memory debug specific
+libxslt.cleanupGlobals()
+libxml2.cleanupParser()
+if libxml2.debugMemory(1) == 0:
+    print "OK"
+else:
+    print "Memory leak %d bytes" % (libxml2.debugMemory(1))
+    libxml2.dumpMemory()