convert some locks to rlocks

frame.go

@@ -533,8 +533,8 @@ func (f *Frame) view(name string) *View { return f.views[name] }
 
 // Views returns a list of all views in the frame.
 func (f *Frame) Views() []*View {
-	f.mu.Lock()
-	defer f.mu.Unlock()
+	f.mu.RLock()
+	defer f.mu.RUnlock()
 
 	other := make([]*View, 0, len(f.views))
 	for _, view := range f.views {

holder.go

@@ -196,15 +196,14 @@ func (h *Holder) index(name string) *Index { return h.indexes[name] }
 
 // Indexes returns a list of all indexes in the holder.
 func (h *Holder) Indexes() []*Index {
-	h.mu.Lock()
-	defer h.mu.Unlock()
-
+	h.mu.RLock()
 	a := make([]*Index, 0, len(h.indexes))
 	for _, index := range h.indexes {
 		a = append(a, index)
 	}
-	sort.Sort(indexSlice(a))
+	h.mu.RUnlock()
 
+	sort.Sort(indexSlice(a))
 	return a
 }