Move tag handling out into graph.Tagger

graph/mongo/iterator.go

@@ -28,6 +28,7 @@ import (
 
 type Iterator struct {
 	iterator.Base
+	tags       graph.Tagger
 	ts         *TripleStore
 	dir        graph.Direction
 	iter       *mgo.Iter
@@ -98,15 +99,29 @@ func (it *Iterator) Close() {
 	it.iter.Close()
 }
 
-func (it *Iterator) Clone() graph.Iterator {
-	var newM graph.Iterator
-	if it.isAll {
-		newM = NewAllIterator(it.ts, it.collection)
-	} else {
-		newM = NewIterator(it.ts, it.collection, it.dir, it.hash)
+func (it *Iterator) Tagger() *graph.Tagger {
+	return &it.tags
+}
+
+func (it *Iterator) TagResults(dst map[string]graph.Value) {
+	for _, tag := range it.tags.Tags() {
+		dst[tag] = it.Result()
 	}
-	newM.CopyTagsFrom(it)
-	return newM
+
+	for tag, value := range it.tags.Fixed() {
+		dst[tag] = value
+	}
+}
+
+func (it *Iterator) Clone() graph.Iterator {
+	var m *Iterator
+	if it.isAll {
+		m = NewAllIterator(it.ts, it.collection)
+	} else {
+		m = NewIterator(it.ts, it.collection, it.dir, it.hash)
+	}
+	m.tags.CopyFrom(it)
+	return m
 }
 
 func (it *Iterator) Next() (graph.Value, bool) {

graph/mongo/triplestore_iterator_optimize.go

@@ -42,9 +42,10 @@ func (ts *TripleStore) optimizeLinksTo(it *iterator.LinksTo) (graph.Iterator, bo
 				panic("Sizes lie")
 			}
 			newIt := ts.TripleIterator(it.Direction(), val)
-			newIt.CopyTagsFrom(it)
-			for _, tag := range primary.Tags() {
-				newIt.AddFixedTag(tag, val)
+			nt := newIt.Tagger()
+			nt.CopyFrom(it)
+			for _, tag := range primary.Tagger().Tags() {
+				nt.AddFixed(tag, val)
 			}
 			it.Close()
 			return newIt, true