impl/memory: Disallow empty namespace.

impl/memory/info.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 memory
 
 import (
         "fmt"
         "regexp"
 
@@ skipping 11 matching lines @@
 
 var defaultGlobalInfoData = globalInfoData{
         // versionID returns X.Y where Y is autogenerated by appengine, and X is
         // whatever's in app.yaml.
         versionID: "testVersionID.1",
         requestID: "test-request-id",
 }
 
 type globalInfoData struct {
         appid     string
-        namespace string
+        namespace *string
         versionID string
         requestID string
 }
 
+func (gid *globalInfoData) getNamespace() (string, bool) {
+        if ns := gid.namespace; ns != nil {
+                return *ns, true
+        }
+        return "", false
+}
+
 func curGID(c context.Context) *globalInfoData {
         if gid, ok := c.Value(giContextKey).(*globalInfoData); ok {
                 return gid
         }
         return &defaultGlobalInfoData
 }
 
 func useGID(c context.Context, f func(mod *globalInfoData)) context.Context {
         cur := curGID(c)
         if cur == nil {
@@ skipping 14 matching lines @@
 }
 
 type giImpl struct {
         info.Interface
         *globalInfoData
         c context.Context
 }
 
 var _ = info.Interface((*giImpl)(nil))
 
-func (gi *giImpl) GetNamespace() string {
-        return gi.namespace
+func (gi *giImpl) GetNamespace() (string, bool) {
+        return gi.getNamespace()
 }
 
 func (gi *giImpl) Namespace(ns string) (ret context.Context, err error) {
         if !validNamespace.MatchString(ns) {
                 return nil, fmt.Errorf("appengine: namespace %q does not match /%s/", ns, validNamespace)
         }
 
         return useGID(gi.c, func(mod *globalInfoData) {
-                mod.namespace = ns
+                mod.namespace = &ns
         }), nil
 }
 
 func (gi *giImpl) MustNamespace(ns string) context.Context {
         ret, err := gi.Namespace(ns)
         if err != nil {
                 panic(err)
         }
         return ret
 }
@@ skipping 26 matching lines @@
         return useGID(gi.c, func(mod *globalInfoData) {
                 mod.versionID = v
         })
 }
 
 func (gi *giImpl) SetRequestID(v string) context.Context {
         return useGID(gi.c, func(mod *globalInfoData) {
                 mod.requestID = v
         })
 }