util: introduce virXMLNodeContentString

It's equivalent of calling virXPathString("string(.)", ctxt) but it
doesn't have to use the XPath resolving and parsing.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

src/libvirt_private.syms

@@ -2954,6 +2954,7 @@ virVHBAPathExists;
 virXMLCheckIllegalChars;
 virXMLChildElementCount;
 virXMLExtractNamespaceXML;
+virXMLNodeContentString;
 virXMLNodeNameEqual;
 virXMLNodeSanitizeNamespaces;
 virXMLNodeToString;

src/util/virxml.c

@@ -540,6 +540,22 @@ virXMLPropStringLimit(xmlNodePtr node,
 }
 
 
+/**
+ * virXMLNodeContentString:
+ * @node: XML dom node pointer
+ *
+ * Convenience function to return copy of content of an XML node.
+ *
+ * Returns the content value as string or NULL in case of failure.
+ * The caller is responsible for freeing the returned buffer.
+ */
+char *
+virXMLNodeContentString(xmlNodePtr node)
+{
+    return (char *)xmlNodeGetContent(node);
+}
+
+
 /**
  * virXPathBoolean:
  * @xpath: the XPath string to evaluate

src/util/virxml.h

@@ -76,6 +76,7 @@ char *          virXMLPropString(xmlNodePtr node,
 char *     virXMLPropStringLimit(xmlNodePtr node,
                                  const char *name,
                                  size_t maxlen);
+char *   virXMLNodeContentString(xmlNodePtr node);
 long     virXMLChildElementCount(xmlNodePtr node);
 
 /* Internal function; prefer the macros below.  */