Rename triple* -> quad* files

graph/leveldb/quadstore_iterator_optimize.go

@@ -0,0 +1,55 @@
+// Copyright 2014 The Cayley Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package leveldb
+
+import (
+	"github.com/google/cayley/graph"
+	"github.com/google/cayley/graph/iterator"
+)
+
+func (ts *TripleStore) OptimizeIterator(it graph.Iterator) (graph.Iterator, bool) {
+	switch it.Type() {
+	case graph.LinksTo:
+		return ts.optimizeLinksTo(it.(*iterator.LinksTo))
+
+	}
+	return it, false
+}
+
+func (ts *TripleStore) optimizeLinksTo(it *iterator.LinksTo) (graph.Iterator, bool) {
+	subs := it.SubIterators()
+	if len(subs) != 1 {
+		return it, false
+	}
+	primary := subs[0]
+	if primary.Type() == graph.Fixed {
+		size, _ := primary.Size()
+		if size == 1 {
+			if !graph.Next(primary) {
+				panic("unexpected size during optimize")
+			}
+			val := primary.Result()
+			newIt := ts.TripleIterator(it.Direction(), val)
+			nt := newIt.Tagger()
+			nt.CopyFrom(it)
+			for _, tag := range primary.Tagger().Tags() {
+				nt.AddFixed(tag, val)
+			}
+			it.Close()
+			return newIt, true
+		}
+	}
+	return it, false
+}