Fixing references from node.

- References to old nodes replaced by references to new ones.
- Added API for this to node.
- Implemented reference fixing in XFR.

refs #1037 @20m

src/dnslib/node.c

@@ -383,6 +383,47 @@ void dnslib_node_set_new_node(dnslib_node_t *node,
 
 /*----------------------------------------------------------------------------*/
 
+void dnslib_node_update_refs(dnslib_node_t *node)
+{
+	// reference to previous node
+	if (node->prev && dnslib_node_is_old(node->prev)) {
+		assert(node->prev->new_node != NULL);
+		node->prev = node->prev->new_node;
+	}
+
+	// reference to next node
+	if (node->next && dnslib_node_is_old(node->next)) {
+		assert(node->next->new_node != NULL);
+		node->next = node->next->new_node;
+	}
+
+	// reference to parent
+	if (node->parent && dnslib_node_is_old(node->parent)) {
+		assert(node->parent->new_node != NULL);
+		node->parent = node->parent->new_node;
+	}
+
+	// reference to wildcard child
+	if (node->wildcard_child && dnslib_node_is_old(node->wildcard_child)) {
+		assert(node->wildcard_child->new_node != NULL);
+		node->wildcard_child = node->wildcard_child->new_node;
+	}
+
+	// reference to NSEC3 node
+	if (node->nsec3_node && dnslib_node_is_old(node->nsec3_node)) {
+		assert(node->nsec3_node->new_node != NULL);
+		node->nsec3_node = node->nsec3_node->new_node;
+	}
+
+	// reference to NSEC3 referrer
+	if (node->nsec3_referer && dnslib_node_is_old(node->nsec3_referer)) {
+		assert(node->nsec3_referer->new_node != NULL);
+		node->nsec3_referer = node->nsec3_referer->new_node;
+	}
+}
+
+/*----------------------------------------------------------------------------*/
+
 void dnslib_node_set_deleg_point(dnslib_node_t *node)
 {
 	dnslib_node_flags_set_deleg(&node->flags);

src/dnslib/node.h

@@ -275,6 +275,8 @@ dnslib_node_t *dnslib_node_get_new_node(const dnslib_node_t *node);
 void dnslib_node_set_new_node(dnslib_node_t *node,
                               dnslib_node_t *new_node);
 
+void dnslib_node_update_refs(dnslib_node_t *node);
+
 /*!
  * \brief Mark the node as a delegation point.
  *

src/knot/server/xfr-in.c

@@ -2005,8 +2005,12 @@ static int xfrin_apply_changeset(dnslib_zone_contents_t *contents,
 
 /*----------------------------------------------------------------------------*/
 
-static int xfrin_finalize_contents(dnslib_zone_contents_t *contents)
+static int xfrin_finalize_contents(dnslib_zone_contents_t *contents,
+                                   xfrin_changes_t *changes)
 {
+	// don't know what should have been done here, except for one thing:
+	// walk through the zone and remove empty nodes (save them in the
+	// old nodes list). But only those having no children!!!
 	return KNOT_ENOTSUP;
 }
 
@@ -2014,7 +2018,23 @@ static int xfrin_finalize_contents(dnslib_zone_contents_t *contents)
 
 static void xfrin_fix_refs_in_node(dnslib_zone_tree_node_t *tnode, void *data)
 {
+	assert(tnode != NULL);
+	assert(data != NULL);
+
+	xfrin_changes_t *changes = (xfrin_changes_t *)data;
+
+	// 1) Fix the reference to the node to the new one if there is some
+	dnslib_node_t *node = tnode->node;
+
+	dnslib_node_t *new_node = dnslib_node_new_node(old_node);
+	if (new_node != NULL) {
+		assert(dnslib_node_rrset_count(new_node) > 0);
+		node = new_node;
+		tnode->node = new_node;
+	}
 
+	// 2) fix references from the node remaining in the zone
+	dnslib_node_update_refs(node);
 }
 
 /*----------------------------------------------------------------------------*/
@@ -2133,7 +2153,7 @@ int xfrin_apply_changesets(dnslib_zone_t *zone, xfrin_changesets_t *chsets)
 	/*
 	 * Finalize the zone contents.
 	 */
-	ret = xfrin_finalize_contents(contents_copy);
+	ret = xfrin_finalize_contents(contents_copy, changes);
 	if (ret != KNOT_EOK) {
 		xfrin_rollback_update(contents_copy, &changes);
 		debug_xfr("Failed to finalize new zone contents: %s\n",