[Bindings] accept simple string in string<->xmlNode converter

Some use case ask for passing simple libxml content node (i.e just an
UTF-8 string) when a method argument or a field of the xmlNode* type.
This commit add a static method in bindings/utils.c named
lasso_string_fragment_to_xmlnode which does this transform by trying to
parse an XML document then by trying to parse a well balanced XML
fragment of only one node (if there is more than one node such as in the
string " xxx <tag/> yyy ", we free the node list and return NULL).

1 files changed, 53 insertions, 0 deletions

diff --git a/bindings/utils.c b/bindings/utils.c
new file mode 100644
index 00000000..d7dd4934
--- /dev/null
+++ b/bindings/utils.c
@@ -0,0 +1,53 @@
+/*
+ * In this file we put utility functions shared by all bindings.
+ *
+ * They usually are data structure manipulation or conversion functions.
+ */
+#include <libxml/tree.h>
+#include "../lasso/utils.h"
+
+/**
+ * lasso_string_fragment_to_xmlnode:
+ * @fragment: a fragment of an XML document
+ * @size: 
+ *
+ * Try to get one and only one node from a string, the node can be a simple string or a single node.
+ *
+ * Return value: a newly allocated xmlNode* or NULL if parsing fails.
+ */
+static xmlNode*
+lasso_string_fragment_to_xmlnode(const char *fragment, int size) {
+	xmlDoc *doc = NULL;
+	xmlNode *node = NULL;
+	xmlNode *list = NULL, *ref = NULL;
+	xmlParserErrors errors;
+
+	if (size == 0) {
+		size = strlen(fragment);
+	}
+
+	/* single node case, with preceding or following spaces */
+	doc = xmlReadMemory(fragment, size, NULL, NULL, XML_PARSE_NONET);
+	if (doc) {
+		node = xmlDocGetRootElement(doc);
+		if (node != NULL) {
+			node = xmlCopyNode(node, 1);
+			goto cleanup;
+		}
+		lasso_release_doc(doc);
+	}
+	/* simple string */
+	doc = xmlNewDoc(BAD_CAST "1.0");
+	ref = xmlNewNode(NULL, BAD_CAST "root");
+
+	xmlDocSetRootElement(doc, ref);
+	errors  = xmlParseInNodeContext(ref, fragment, size,
+		XML_PARSE_NONET, &list);
+	if (errors == XML_ERR_OK && list != NULL && list->next == NULL) {
+		node = xmlCopyNode(list, 1);
+	}
+cleanup:
+	lasso_release_doc(doc);
+	lasso_release_xml_node_list(list);
+	return node;
+}