xml.c, config,c: Add stylesheets and variable list string parsing

Added functions to open, close, and apply XML Stylesheets
to XML documents.  Although the presence of libxslt was already
being checked by configure, it was only happening if xmldoc was
enabled.  Now it's checked regardless.

Added ability to parse a string consisting of comma separated
name/value pairs into an ast_variable list.  The reverse of
ast_variable_list_join().

Change-Id: I1e1d149be22165a1fb8e88e2903a36bba1a6cf2e

main/xml.c

@@ -36,25 +36,33 @@
 #include <libxml/tree.h>
 #include <libxml/xinclude.h>
 #include <libxml/xpath.h>
+#include <libxml/xpathInternals.h>
 /* libxml2 ast_xml implementation. */
 #ifdef HAVE_LIBXSLT
 	#include <libxslt/xsltInternals.h>
 	#include <libxslt/transform.h>
+	#include <libxslt/xsltutils.h>
 #endif /* HAVE_LIBXSLT */
 
 
 int ast_xml_init(void)
 {
 	LIBXML_TEST_VERSION
-
+#ifdef HAVE_LIBXSLT
+	xsltInit();
+#endif
 	return 0;
 }
 
 int ast_xml_finish(void)
 {
 	xmlCleanupParser();
+#ifdef HAVE_LIBXSLT
 #ifdef HAVE_LIBXSLT_CLEANUP
 	xsltCleanupGlobals();
+#else
+	xsltUninit();
+#endif
 #endif
 
 	return 0;
@@ -68,6 +76,8 @@ struct ast_xml_doc *ast_xml_open(char *filename)
 		return NULL;
 	}
 
+	xmlSubstituteEntitiesDefault(1);
+
 	doc = xmlReadFile(filename, NULL, XML_PARSE_RECOVER);
 	if (!doc) {
 		return NULL;
@@ -309,6 +319,11 @@ struct ast_xml_ns *ast_xml_find_namespace(struct ast_xml_doc *doc, struct ast_xm
 	return (struct ast_xml_ns *) ns;
 }
 
+const char *ast_xml_get_ns_prefix(struct ast_xml_ns *ns)
+{
+	return (const char *) ((xmlNsPtr) ns)->prefix;
+}
+
 const char *ast_xml_get_ns_href(struct ast_xml_ns *ns)
 {
 	return (const char *) ((xmlNsPtr) ns)->href;
@@ -376,13 +391,24 @@ struct ast_xml_node *ast_xml_xpath_get_first_result(struct ast_xml_xpath_results
 	return (struct ast_xml_node *) ((xmlXPathObjectPtr) results)->nodesetval->nodeTab[0];
 }
 
+struct ast_xml_node *ast_xml_xpath_get_result(struct ast_xml_xpath_results *results, int i)
+{
+	return (struct ast_xml_node *) ((xmlXPathObjectPtr) results)->nodesetval->nodeTab[i];
+}
+
 void ast_xml_xpath_results_free(struct ast_xml_xpath_results *results)
 {
+	if (!results) {
+		return;
+	}
 	xmlXPathFreeObject((xmlXPathObjectPtr) results);
 }
 
 int ast_xml_xpath_num_results(struct ast_xml_xpath_results *results)
 {
+	if (!results) {
+		return 0;
+	}
 	return ((xmlXPathObjectPtr) results)->nodesetval->nodeNr;
 }
 
@@ -408,4 +434,149 @@ struct ast_xml_xpath_results *ast_xml_query(struct ast_xml_doc *doc, const char
 	return (struct ast_xml_xpath_results *) result;
 }
 
+struct ast_xml_xpath_results *ast_xml_query_with_namespaces(struct ast_xml_doc *doc, const char *xpath_str,
+	struct ast_xml_namespace_def_vector *namespaces)
+{
+	xmlXPathContextPtr context;
+	xmlXPathObjectPtr result;
+	int i;
+
+	if (!(context = xmlXPathNewContext((xmlDoc *) doc))) {
+		ast_log(LOG_ERROR, "Could not create XPath context!\n");
+		return NULL;
+	}
+
+	for (i = 0; i < AST_VECTOR_SIZE(namespaces); i++) {
+		struct ast_xml_namespace_def ns = AST_VECTOR_GET(namespaces, i);
+		if (xmlXPathRegisterNs(context, (xmlChar *)ns.prefix,
+			(xmlChar *)ns.href) != 0) {
+			xmlXPathFreeContext(context);
+			ast_log(LOG_ERROR, "Could not register namespace %s:%s\n",
+				ns.prefix, ns.href);
+			return NULL;
+		}
+	}
+
+	result = xmlXPathEvalExpression((xmlChar *) xpath_str, context);
+	xmlXPathFreeContext(context);
+	if (!result) {
+		ast_log(LOG_WARNING, "Error for query: %s\n", xpath_str);
+		return NULL;
+	}
+	if (xmlXPathNodeSetIsEmpty(result->nodesetval)) {
+		xmlXPathFreeObject(result);
+		ast_debug(5, "No results for query: %s\n", xpath_str);
+		return NULL;
+	}
+	return (struct ast_xml_xpath_results *) result;
+}
+
+#ifdef HAVE_LIBXSLT
+struct ast_xslt_doc *ast_xslt_open(char *filename)
+{
+	xsltStylesheet *xslt;
+	xmlDoc *xml;
+
+	xmlSubstituteEntitiesDefault(1);
+
+	xml = xmlReadFile(filename, NULL, XML_PARSE_RECOVER);
+	if (!xml) {
+		return NULL;
+	}
+
+	if (xmlXIncludeProcess(xml) < 0) {
+		xmlFreeDoc(xml);
+		return NULL;
+	}
+	xmlXPathOrderDocElems(xml);
+
+	if (!(xslt = xsltParseStylesheetDoc(xml))) {
+		xmlFreeDoc(xml);
+		return NULL;
+	}
+
+	return (struct ast_xslt_doc *) xslt;
+}
+
+struct ast_xslt_doc *ast_xslt_read_memory(char *buffer, size_t size)
+{
+	xsltStylesheet *xslt;
+	xmlDoc *doc;
+
+	if (!buffer) {
+		return NULL;
+	}
+
+	xmlSubstituteEntitiesDefault(1);
+
+	if (!(doc = xmlParseMemory(buffer, (int) size))) {
+		return NULL;
+	}
+
+	if (xmlXIncludeProcess(doc) < 0) {
+		xmlFreeDoc(doc);
+		return NULL;
+	}
+
+	if (!(xslt = xsltParseStylesheetDoc(doc))) {
+		xmlFreeDoc(doc);
+		return NULL;
+	}
+
+	return (struct ast_xslt_doc *) xslt;
+}
+
+void ast_xslt_close(struct ast_xslt_doc *axslt)
+{
+	if (!axslt) {
+		return;
+	}
+
+	xsltFreeStylesheet((xsltStylesheet *) axslt);
+}
+
+struct ast_xml_doc *ast_xslt_apply(struct ast_xslt_doc *axslt, struct ast_xml_doc *axml, const char **params)
+{
+	xsltStylesheet *xslt = (xsltStylesheet *)axslt;
+	xmlDoc *xml = (xmlDoc *)axml;
+	xsltTransformContextPtr ctxt;
+	xmlNs *ns;
+	xmlDoc *res;
+	int options = XSLT_PARSE_OPTIONS;
+
+	/*
+	 * Normally we could just call xsltApplyStylesheet() without creating
+	 * our own transform context but we need to pass parameters to it
+	 * that have namespace prefixes and that's not supported.  Instead
+	 * we have to create a transform context, iterate over the namespace
+	 * declarations in the stylesheet (not the incoming xml document),
+	 * and add them to the transform context's xpath context.
+	 *
+	 * The alternative would be to pass the parameters with namespaces
+	 * as text strings but that's not intuitive and results in much
+	 * slower performance than adding the namespaces here.
+	 */
+	ctxt = xsltNewTransformContext(xslt, xml);
+	xsltSetCtxtParseOptions(ctxt, options);
+
+	for (ns = xslt->doc->children->nsDef; ns; ns = ns->next) {
+		if (xmlXPathRegisterNs(ctxt->xpathCtxt, ns->prefix, ns->href) != 0) {
+			xmlXPathFreeContext(ctxt->xpathCtxt);
+			xsltFreeTransformContext(ctxt);
+			return NULL;
+		}
+	}
+
+	res = xsltApplyStylesheetUser(xslt, xml, params, NULL, NULL, ctxt);
+
+	return (struct ast_xml_doc *)res;
+}
+
+int ast_xslt_save_result_to_string(char **buffer, int *length, struct ast_xml_doc *result,
+	struct ast_xslt_doc *axslt)
+{
+	return xsltSaveResultToString((xmlChar **)buffer, length, (xmlDoc *)result, (xsltStylesheet *)axslt);
+}
+
+#endif /* defined(HAVE_LIBXSLT) */
 #endif /* defined(HAVE_LIBXML2) */