initial mongo indexed linksto

graph/iterator/and_iterator.go

@@ -31,13 +31,15 @@ type And struct {
 	result            graph.Value
 	runstats          graph.IteratorStats
 	err               error
+	qs                graph.QuadStore
 }
 
 // Creates a new And iterator.
-func NewAnd() *And {
+func NewAnd(qs graph.QuadStore) *And {
 	return &And{
 		uid:               NextUID(),
 		internalIterators: make([]graph.Iterator, 0, 20),
+		qs:                qs,
 	}
 }
 
@@ -79,7 +81,7 @@ func (it *And) TagResults(dst map[string]graph.Value) {
 }
 
 func (it *And) Clone() graph.Iterator {
-	and := NewAnd()
+	and := NewAnd(it.qs)
 	and.AddSubIterator(it.primaryIt.Clone())
 	and.tags.CopyFrom(it)
 	for _, sub := range it.internalIterators {

graph/iterator/and_iterator_optimize.go

@@ -78,7 +78,7 @@ func (it *And) Optimize() (graph.Iterator, bool) {
 
 	// The easiest thing to do at this point is merely to create a new And iterator
 	// and replace ourselves with our (reordered, optimized) clone.
-	newAnd := NewAnd()
+	newAnd := NewAnd(it.qs)
 
 	// Add the subiterators in order.
 	for _, sub := range its {
@@ -95,6 +95,16 @@ func (it *And) Optimize() (graph.Iterator, bool) {
 	// the new And (they were unchanged upon calling Optimize() on them, at the
 	// start).
 	it.cleanUp()
+
+	// Ask the graph.QuadStore if we can be replaced. Often times, this is a great
+	// optimization opportunity (there's a fixed iterator underneath us, for
+	// example).
+	newReplacement, hasOne := it.qs.OptimizeIterator(newAnd)
+	if hasOne {
+		newAnd.Close()
+		return newReplacement, true
+	}
+
 	return newAnd, true
 }