A transparent cache for datastore, backed by memcache.

service/memcache/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 memcache
 
 // RawCB is a simple error callback for most of the methods in RawInterface.
 type RawCB func(error)
 
 // RawItemCB is the callback for RawInterface.GetMulti. It takes the retrieved
-// item and the error for that item (e.g. ErrCacheMiss) if there was one..
+// item and the error for that item (e.g. ErrCacheMiss) if there was one. Item
+// is guaranteed to be nil if error is not nil.
 type RawItemCB func(Item, error)
 
 // RawInterface is the full interface to the memcache service.
 type RawInterface interface {
         NewItem(key string) Item
 
         AddMulti(items []Item, cb RawCB) error
         SetMulti(items []Item, cb RawCB) error
         GetMulti(keys []string, cb RawItemCB) error
         DeleteMulti(keys []string, cb RawCB) error
         CompareAndSwapMulti(items []Item, cb RawCB) error
 
         Increment(key string, delta int64, initialValue *uint64) (newValue uint64, err error)
 
         Flush() error
 
         Stats() (*Statistics, error)
 }