impl/memory: Implement Queries

service/datastore/datastore.go

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package datastore
 
 import (
         "fmt"
         "reflect"
 
@@ skipping 14 matching lines @@
 
 func (d *datastoreImpl) KeyForObjErr(src interface{}) (Key, error) {
         return newKeyObjErr(d.NewKey, src)
 }
 
 func (d *datastoreImpl) DecodeCursor(s string) (Cursor, error) {
         return d.RawInterface.DecodeCursor(s)
 }
 
 func (d *datastoreImpl) Run(q Query, cbIface interface{}) error {
+        if cbIface == nil {
+                return fmt.Errorf("cannot use nil callback when Running query")
+        }
+
         // TODO(riannucci): Profile and determine if any of this is causing a real
         // slowdown. Could potentially cache reflection stuff by cbType?
         cbTyp := reflect.TypeOf(cbIface)
 
         badSig := false
         mat := multiArgType{}
         isKey := false
 
         if cbTyp.Kind() == reflect.Func && cbTyp.NumIn() == 2 && cbTyp.NumOut() == 1 {
                 firstArg := cbTyp.In(0)
@@ skipping 169 matching lines @@
         err = lme.Get()
         if err == nil {
                 err = extErr
         }
         return
 }
 
 func (d *datastoreImpl) Raw() RawInterface {
         return d.RawInterface
 }