Make the rest of the services have a similar raw/user interface structure.

impl/prod/memcache.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 prod
 
 import (
         "time"
 
         mc "github.com/luci/gae/service/memcache"
-        "github.com/luci/luci-go/common/errors"
         "golang.org/x/net/context"
+        "google.golang.org/appengine"
         "google.golang.org/appengine/memcache"
 )
 
 // useMC adds a gae.Memcache implementation to context, accessible
 // by gae.GetMC(c)
 func useMC(c context.Context) context.Context {
-        return mc.SetFactory(c, func(ci context.Context) mc.Interface {
+        return mc.SetRawFactory(c, func(ci context.Context) mc.RawInterface {
                 return mcImpl{ci}
         })
 }
 
 type mcImpl struct{ context.Context }
 
 type mcItem struct {
         i *memcache.Item
 }
 
 var _ mc.Item = mcItem{}
 
 func (i mcItem) Key() string               { return i.i.Key }
 func (i mcItem) Value() []byte             { return i.i.Value }
-func (i mcItem) Object() interface{}       { return i.i.Object }
 func (i mcItem) Flags() uint32             { return i.i.Flags }
 func (i mcItem) Expiration() time.Duration { return i.i.Expiration }
 
 func (i mcItem) SetKey(k string) mc.Item {
         i.i.Key = k
         return i
 }
 func (i mcItem) SetValue(v []byte) mc.Item {
         i.i.Value = v
         return i
 }
-func (i mcItem) SetObject(o interface{}) mc.Item {
-        i.i.Object = o
-        return i
-}
 func (i mcItem) SetFlags(f uint32) mc.Item {
         i.i.Flags = f
         return i
 }
 func (i mcItem) SetExpiration(d time.Duration) mc.Item {
         i.i.Expiration = d
         return i
 }
 
+func (i mcItem) SetAll(other mc.Item) {
+        o := other.(mcItem)
+        *i.i = *o.i
+        val := i.i.Value
+        i.i.Value = make([]byte, len(val))
+        copy(i.i.Value, val)
+}
+
 // mcR2FErr (MC real-to-fake w/ error) converts a *memcache.Item to a mc.Item,
 // and passes along an error.
 func mcR2FErr(i *memcache.Item, err error) (mc.Item, error) {
         if err != nil {
                 return nil, err
         }
         return mcItem{i}, nil
 }
 
 // mcF2R (MC fake-to-real) converts a mc.Item. i must originate from inside
@@ skipping 15 matching lines @@
         for i, itm := range items {
                 realItems[i] = mcF2R(itm)
         }
         return realItems
 }
 
 func (m mcImpl) NewItem(key string) mc.Item {
         return mcItem{&memcache.Item{Key: key}}
 }
 
-//////// MCSingleReadWriter
-func (m mcImpl) Add(item mc.Item) error {
-        return memcache.Add(m.Context, mcF2R(item))
-}
-func (m mcImpl) Set(item mc.Item) error {
-        return memcache.Set(m.Context, mcF2R(item))
-}
-func (m mcImpl) Delete(key string) error {
-        return memcache.Delete(m.Context, key)
-}
-func (m mcImpl) Get(key string) (mc.Item, error) {
-        return mcR2FErr(memcache.Get(m.Context, key))
-}
-func (m mcImpl) CompareAndSwap(item mc.Item) error {
-        return memcache.CompareAndSwap(m.Context, mcF2R(item))
+func doCB(err error, cb mc.RawCB) error {
+        if me, ok := err.(appengine.MultiError); ok {

[dnj, 2015/08/03 22:37:25]

It's guaranteed that "DeleteMulti" will return a MultiError? Even if it fully
succeeds?

If not, a scenario can exist where the callbacks aren't invoked.

[iannucci, 2015/08/04 01:21:21]

Completely correct. That's why this method exists.

[dnj (Google), 2015/08/04 03:48:03]

Acknowledged.

+                for _, err := range me {
+                        cb(err)
+                }
+                err = nil
+        }
+        return err
 }
 
-//////// MCMultiReadWriter
-func (m mcImpl) DeleteMulti(keys []string) error {
-        return errors.Fix(memcache.DeleteMulti(m.Context, keys))
+func (m mcImpl) DeleteMulti(keys []string, cb mc.RawCB) error {
+        return doCB(memcache.DeleteMulti(m.Context, keys), cb)
 }
-func (m mcImpl) AddMulti(items []mc.Item) error {
-        return errors.Fix(memcache.AddMulti(m.Context, mcMF2R(items)))
+
+func (m mcImpl) AddMulti(items []mc.Item, cb mc.RawCB) error {
+        return doCB(memcache.AddMulti(m.Context, mcMF2R(items)), cb)
 }
-func (m mcImpl) SetMulti(items []mc.Item) error {
-        return errors.Fix(memcache.SetMulti(m.Context, mcMF2R(items)))
+
+func (m mcImpl) SetMulti(items []mc.Item, cb mc.RawCB) error {
+        return doCB(memcache.SetMulti(m.Context, mcMF2R(items)), cb)
 }
-func (m mcImpl) GetMulti(keys []string) (map[string]mc.Item, error) {
+
+func (m mcImpl) GetMulti(keys []string, cb mc.RawItemCB) error {
         realItems, err := memcache.GetMulti(m.Context, keys)
         if err != nil {
-                return nil, errors.Fix(err)
+                return err
         }
-        items := make(map[string]mc.Item, len(realItems))
-        for k, itm := range realItems {
-                items[k] = mcItem{itm}
+        for _, k := range keys {
+                itm := realItems[k]
+                if itm == nil {
+                        cb(nil, memcache.ErrCacheMiss)
+                } else {
+                        cb(mcItem{itm}, nil)
+                }
         }
-        return items, err
-}
-func (m mcImpl) CompareAndSwapMulti(items []mc.Item) error {
-        return errors.Fix(memcache.CompareAndSwapMulti(m.Context, mcMF2R(items)))
+        return nil
 }
 
-//////// MCIncrementer
-func (m mcImpl) Increment(key string, delta int64, initialValue uint64) (uint64, error) {
-        return memcache.Increment(m.Context, key, delta, initialValue)
-}
-func (m mcImpl) IncrementExisting(key string, delta int64) (uint64, error) {
-        return memcache.IncrementExisting(m.Context, key, delta)
+func (m mcImpl) CompareAndSwapMulti(items []mc.Item, cb mc.RawCB) error {
+        return doCB(memcache.CompareAndSwapMulti(m.Context, mcMF2R(items)), cb)
 }
 
-//////// MCFlusher
+func (m mcImpl) Increment(key string, delta int64, initialValue *uint64) (uint64, error) {
+        if initialValue == nil {
+                return memcache.IncrementExisting(m.Context, key, delta)
+        } else {
+                return memcache.Increment(m.Context, key, delta, *initialValue)
+        }
+}
+
 func (m mcImpl) Flush() error {
         return memcache.Flush(m.Context)
 }
 
-//////// MCStatter
 func (m mcImpl) Stats() (*mc.Statistics, error) {
         stats, err := memcache.Stats(m.Context)
         if err != nil {
                 return nil, err
         }
         return (*mc.Statistics)(stats), nil
 }