client: fix spurious warning in XML writer

It seems that libxml doesn't like generating an empty
document. Therefore, we initialize the writer only when we are sure we
will get content.

diff --git a/src/client/xml_writer.c b/src/client/xml_writer.c
index c38fdfcf8c0de18439c9e14b741ede9a1177847a..3441866b03e2f5de6d14e47166e522576918f120 100644 (file)
--- a/src/client/xml_writer.c
+++ b/src/client/xml_writer.c
@@ -39,9 +39,24 @@ struct xml_writer_private {
        xmlDocPtr doc;
 };
 
+void xml_new_writer(struct xml_writer_private *priv)
+{
+       priv->xw = xmlNewTextWriterDoc(&(priv->doc), 0);
+       if (!priv->xw)
+               fatalx("lldpctl", "cannot create xml writer");
+
+       xmlTextWriterSetIndent(priv->xw, 4);
+
+       if (xmlTextWriterStartDocument(priv->xw, NULL, "UTF-8", NULL) < 0 )
+               fatalx("lldpctl", "cannot start xml document");
+}
+
 void xml_start(struct writer *w , const char *tag, const char *descr ) {
        struct xml_writer_private *p = w->priv;
 
+       if (p->depth == 0)
+               xml_new_writer(p);
+
        if (xmlTextWriterStartElement(p->xw, BAD_CAST tag) < 0)
                log_warnx("lldpctl", "cannot start '%s' element", tag);
 
@@ -66,18 +81,6 @@ void xml_data(struct writer *w, const char *data) {
                log_warnx("lldpctl", "cannot add '%s' as data to element", data?data:"(none)");
 }
 
-void xml_new_writer(struct xml_writer_private *priv)
-{
-       priv->xw = xmlNewTextWriterDoc(&(priv->doc), 0);
-       if (!priv->xw)
-               fatalx("lldpctl", "cannot create xml writer");
-
-       xmlTextWriterSetIndent(priv->xw, 4);
-
-       if (xmlTextWriterStartDocument(priv->xw, NULL, "UTF-8", NULL) < 0 )
-               fatalx("lldpctl", "cannot start xml document");
-}
-
 void xml_end(struct writer *w) {
        struct xml_writer_private *p = w->priv;
 
@@ -93,13 +96,9 @@ void xml_end(struct writer *w) {
                }
 
                xmlFreeTextWriter(p->xw);
-
                if (!failed)
                        xmlDocDump(p->fh, p->doc);
-
                xmlFreeDoc(p->doc);
-
-               xml_new_writer(p);
        }
 }
 
@@ -110,9 +109,7 @@ void xml_finish(struct writer *w) {
                /* memory leak... */
        }
 
-       xmlFreeTextWriter(p->xw);
-       xmlFreeDoc(p->doc);
-       free(w->priv);
+       free(p);
        free(w);
 }
 
@@ -129,8 +126,6 @@ struct writer *xml_init(FILE *fh) {
        priv->fh = fh;
        priv->depth = 0;
 
-       xml_new_writer(priv);
-
        result = malloc(sizeof(struct writer));
        if (!result)
                fatalx("lldpctl", "out of memory");