util: xml: introduce virXMLNamespaceRegister

A wrapper around xmlXPathRegisterNs that will save us
from having to include xpathInternals.h everywhere
we want to use a custom namespace and open-coding
the strings already contained in virXMLNamespace.
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NJiri Denemark <jdenemar@redhat.com>

src/util/virxml.c

@@ -24,6 +24,8 @@
 #include <math.h>               /* for isnan() */
 #include <sys/stat.h>
 
+#include <libxml/xpathInternals.h>
+
 #include "virerror.h"
 #include "virxml.h"
 #include "virbuffer.h"
@@ -1416,3 +1418,20 @@ virXMLNamespaceFormatNS(virBufferPtr buf,
 {
     virBufferAsprintf(buf, " xmlns:%s='%s'", ns->prefix, ns->href());
 }
+
+
+int
+virXMLNamespaceRegister(xmlXPathContextPtr ctxt,
+                        virXMLNamespace const *ns)
+{
+    if (xmlXPathRegisterNs(ctxt,
+                           BAD_CAST ns->prefix,
+                           BAD_CAST ns->href()) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Failed to register xml namespace '%s'"),
+                       ns->href());
+        return -1;
+    }
+
+    return 0;
+}

src/util/virxml.h

@@ -265,3 +265,6 @@ typedef virXMLNamespace *virXMLNamespacePtr;
 void
 virXMLNamespaceFormatNS(virBufferPtr buf,
                         virXMLNamespace const *ns);
+int
+virXMLNamespaceRegister(xmlXPathContextPtr ctxt,
+                        virXMLNamespace const *ns);