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

go/src/infra/gae/libs/wrapper/memory/context.go

Index: go/src/infra/gae/libs/wrapper/memory/context.go
diff --git a/go/src/infra/gae/libs/wrapper/memory/context.go b/go/src/infra/gae/libs/wrapper/memory/context.go
deleted file mode 100644
index b6607fcc4d0231f8b23874083be039c09a157545..0000000000000000000000000000000000000000
--- a/go/src/infra/gae/libs/wrapper/memory/context.go
+++ /dev/null
@@ -1,168 +0,0 @@
-// 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 memory
-
-import (
-	"errors"
-	"sync"
-
-	"golang.org/x/net/context"
-
-	"appengine/datastore"
-)
-
-type memContextObj interface {
-	sync.Locker
-	canApplyTxn(m memContextObj) bool
-	applyTxn(c context.Context, m memContextObj)
-
-	endTxn()
-	mkTxn(*datastore.TransactionOptions) (memContextObj, error)
-}
-
-type memContext []memContextObj
-
-var _ = memContextObj((memContext)(nil))
-
-func newMemContext() memContext {
-	return memContext{
-		newTaskQueueData(),
-		newDataStoreData(),
-	}
-}
-
-type memContextIdx int
-
-const (
-	memContextTQIdx memContextIdx = iota
-	memContextDSIdx
-)
-
-func (m memContext) Get(itm memContextIdx) memContextObj {
-	return m[itm]
-}
-
-func (m memContext) Lock() {
-	for _, itm := range m {
-		itm.Lock()
-	}
-}
-
-func (m memContext) Unlock() {
-	for i := len(m) - 1; i >= 0; i-- {
-		m[i].Unlock()
-	}
-}
-
-func (m memContext) endTxn() {
-	for _, itm := range m {
-		itm.endTxn()
-	}
-}
-
-func (m memContext) mkTxn(o *datastore.TransactionOptions) (memContextObj, error) {
-	ret := make(memContext, len(m))
-	for i, itm := range m {
-		newItm, err := itm.mkTxn(o)
-		if err != nil {
-			return nil, err
-		}
-		ret[i] = newItm
-	}
-	return ret, nil
-}
-
-func (m memContext) canApplyTxn(txnCtxObj memContextObj) bool {
-	txnCtx := txnCtxObj.(memContext)
-	for i := range m {
-		if !m[i].canApplyTxn(txnCtx[i]) {
-			return false
-		}
-	}
-	return true
-}
-
-func (m memContext) applyTxn(c context.Context, txnCtxObj memContextObj) {
-	txnCtx := txnCtxObj.(memContext)
-	for i := range m {
-		m[i].applyTxn(c, txnCtx[i])
-	}
-}
-
-// Use adds implementations for the following gae/wrapper interfaces to the
-// context:
-//   * wrapper.Datastore
-//   * wrapper.TaskQueue
-//   * wrapper.Memcache
-//   * wrapper.GlobalInfo
-//
-// These can be retrieved with the "gae/wrapper".Get functions.
-//
-// The implementations are all backed by an in-memory implementation, and start
-// with an empty state.
-//
-// Using this more than once per context.Context will cause a panic.
-func Use(c context.Context) context.Context {
-	if c.Value(memContextKey) != nil {
-		panic(errors.New("memory.Use: called twice on the same Context"))
-	}
-	c = context.WithValue(
-		context.WithValue(c, memContextKey, newMemContext()),
-		giContextKey, &globalInfoData{})
-	return useTQ(useDS(useMC(useGI(c))))
-}
-
-func cur(c context.Context) (p memContext) {
-	p, _ = c.Value(memContextKey).(memContext)
-	return
-}
-
-type memContextKeyType int
-
-var memContextKey memContextKeyType
-
-// weird stuff
-
-// RunInTransaction is here because it's really a service-wide transaction, not
-// just in the datastore. TaskQueue behaves differently in a transaction in
-// a couple ways, for example.
-//
-// It really should have been appengine.Context.RunInTransaction(func(tc...)),
-// but because it's not, this method is on dsImpl instead to mirror the official
-// API.
-//
-// The fake implementation also differs from the real implementation because the
-// fake TaskQueue is NOT backed by the fake Datastore. This is done to make the
-// test-access API for TaskQueue better (instead of trying to reconstitute the
-// state of the task queue from a bunch of datastore accesses).
-func (d *dsImpl) RunInTransaction(f func(context.Context) error, o *datastore.TransactionOptions) error {
-	curMC := cur(d.c)
-
-	txnMC, err := curMC.mkTxn(o)
-	if err != nil {
-		return err
-	}
-
-	defer func() {
-		txnMC.Lock()
-		defer txnMC.Unlock()
-
-		txnMC.endTxn()
-	}()
-
-	if err = f(context.WithValue(d.c, memContextKey, txnMC)); err != nil {
-		return err
-	}
-
-	txnMC.Lock()
-	defer txnMC.Unlock()
-
-	if curMC.canApplyTxn(txnMC) {
-		curMC.applyTxn(d.c, txnMC)
-	} else {
-		return datastore.ErrConcurrentTransaction
-	}
-	return nil
-}