Reland: Refactor current GAE abstraction library to be free of the SDK*

go/src/infra/gae/libs/wrapper/unsafe/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 unsafe
-
-import (
-        "time"
-
-        "unsafe"
-
-        "appengine/memcache"
-)
-
-// Item is duplicated from appengine/memcache.
-type Item struct {
-        Key        string
-        Value      []byte
-        Object     interface{}
-        Flags      uint32
-        Expiration time.Duration
-        CasID      uint64
-}
-
-func init() {
-        // we can't actually refer to casID by name, but we can refer to everything
-        // else, and ensure that everything lines up. This should catch an api change,
-        // but wouldn't catch something like uint64 -> int64.
-        if unsafe.Sizeof(memcache.Item{}) != unsafe.Sizeof(Item{}) {
-                panic("memcache.Item and Item mismatch sizes")
-        }
-        if unsafe.Offsetof(memcache.Item{}.Key) != unsafe.Offsetof(Item{}.Key) {
-                panic("memcache.Item and Item mismatch Key")
-        }
-        if unsafe.Offsetof(memcache.Item{}.Value) != unsafe.Offsetof(Item{}.Value) {
-                panic("memcache.Item and Item mismatch Value")
-        }
-        if unsafe.Offsetof(memcache.Item{}.Object) != unsafe.Offsetof(Item{}.Object) {
-                panic("memcache.Item and Item mismatch Object")
-        }
-        if unsafe.Offsetof(memcache.Item{}.Flags) != unsafe.Offsetof(Item{}.Flags) {
-                panic("memcache.Item and Item mismatch Flags")
-        }
-        if unsafe.Offsetof(memcache.Item{}.Expiration) != unsafe.Offsetof(Item{}.Expiration) {
-                panic("memcache.Item and Item mismatch Expiration")
-        }
-}
-
-// MCSetCasID sets the private .casID field of memcache.Item.
-func MCSetCasID(i *memcache.Item, val uint64) {
-        mci := (*Item)(unsafe.Pointer(i))
-        mci.CasID = val
-}
-
-// MCGetCasID retrieves the private .casID field of memcache.Item.
-func MCGetCasID(i *memcache.Item) uint64 {
-        return (*Item)(unsafe.Pointer(i)).CasID
-}