Get rid of awkward proto argument to Interface.Run

service/datastore/raw_interface.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"
 
         "golang.org/x/net/context"
@@ skipping 33 matching lines @@
         EventualConsistency() Query
         Filter(filterStr string, value interface{}) Query
         KeysOnly() Query
         Limit(limit int) Query
         Offset(offset int) Query
         Order(fieldName string) Query
         Project(fieldNames ...string) Query
         Start(c Cursor) Query
 }
 
+// CursorCB is used to obtain a Cursor while Run'ing a query on either
+// Interface or RawInterface.
+//
+// it can be invoked to obtain the current cursor.
+type CursorCB func() (Cursor, error)
+
 // RawRunCB is the callback signature provided to RawInterface.Run
 //
 //   - key is the Key of the entity
 //   - val is the data of the entity (or nil, if the query was keys-only)
-//   - getCursor can be invoked to obtain the current cursor.
 //
 // Return true to continue iterating through the query results, or false to stop.
-type RawRunCB func(key Key, val PropertyMap, getCursor func() (Cursor, error)) bool
+type RawRunCB func(key Key, val PropertyMap, getCursor CursorCB) bool
 
 // GetMultiCB is the callback signature provided to RawInterface.GetMulti
 //
 //   - val is the data of the entity
 //     * It may be nil if some of the keys to the GetMulti were bad, since all
 //       keys are validated before the RPC occurs!
 //   - err is an error associated with this entity (e.g. ErrNoSuchEntity).
 type GetMultiCB func(val PropertyMap, err error)
 
 // PutMultiCB is the callback signature provided to RawInterface.PutMulti
@@ skipping 109 matching lines @@
         // Callback execues once per key, in the order of keys. Callback may not
         // execute at all if there's a server error.
         //
         // NOTE: Implementations and filters are guaranteed that
         //   - len(keys) > 0
         //   - all keys are Valid, !Incomplete, and in the current namespace
         //   - none keys of the keys are 'special' (use a kind prefixed with '__')
         //   - cb is not nil
         DeleteMulti(keys []Key, cb DeleteMultiCB) error
 }