plugin/file: Rename do to walk and cleanup and document (#2987)

* plugin/file: Rename do to walk, cleanup and document

* This renames Do to Walk to be more inline with Go standards. Also make
  it return an error instead of a bool.
  Also give give walk access to rrs. Alternatively e.m could be
  exported, but just access the map of rrs should work as well. Another
  alternative would be adding a whole bunch of helper functions, but
  those need grab and return the data. Just having access to the rrs
  should be easiest for most Walks.
* It adds Type and TypeForWildcard to show the different functions
* *Removes* the identical RR check when inserting; this was only done
  for A, AAAA and MX and not finished; removed under the mantra garbage
  in garbage out.
* Reuses Types to return all the types in an *tree.Elem

Signed-off-by: Miek Gieben <miek@miek.nl>

* better comments

Signed-off-by: Miek Gieben <miek@miek.nl>

1 files changed, 5 insertions, 6 deletions

diff --git a/plugin/file/tree/tree.go b/plugin/file/tree/tree.go
index ed33c09a4..3aeeba4d5 100644
--- a/plugin/file/tree/tree.go
+++ b/plugin/file/tree/tree.go
@@ -275,7 +275,8 @@ func (n *Node) deleteMax() (root *Node, d int) {
 	return
 }
 
-// Delete removes rr from the tree, is the node turns empty, that node is deleted with DeleteNode.
+// Delete removes all RRs of type rr.Header().Rrtype from e. If after the deletion of rr the node is empty the
+// entire node is deleted.
 func (t *Tree) Delete(rr dns.RR) {
 	if t.Root == nil {
 		return
@@ -283,15 +284,13 @@ func (t *Tree) Delete(rr dns.RR) {
 
 	el, _ := t.Search(rr.Header().Name)
 	if el == nil {
-		t.deleteNode(rr)
 		return
 	}
-	// Delete from this element.
-	empty := el.Delete(rr)
-	if empty {
+	el.Delete(rr)
+	if el.Empty() {
 		t.deleteNode(rr)
-		return
 	}
+	return
 }
 
 // DeleteNode deletes the node that matches rr according to Less().