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

go/src/infra/gae/libs/gae/prod/datastore_key.go

Index: go/src/infra/gae/libs/gae/prod/datastore_key.go
diff --git a/go/src/infra/gae/libs/gae/prod/datastore_key.go b/go/src/infra/gae/libs/gae/prod/datastore_key.go
new file mode 100644
index 0000000000000000000000000000000000000000..03a39780f869cc7fdb7db7cd41ff6083707214b8
--- /dev/null
+++ b/go/src/infra/gae/libs/gae/prod/datastore_key.go
@@ -0,0 +1,56 @@
+// 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 (
+	"infra/gae/libs/gae"
+	"infra/gae/libs/gae/helper"
+
+	"google.golang.org/appengine/datastore"
+)
+
+type dsKeyImpl struct {

[Vadim Sh., 2015/07/14 00:12:37]

any reason it can't be

type dsKeyImpl *datastore.Key?

Or 

type dsKeyImpl struct {
  datastore.Key
}

Point to pointer is sort of bad.

[iannucci, 2015/07/14 01:07:46]

Note that it's all bare-struct receivers below, so it shouldn't ever be a
pointer-to-a-pointer. I also felt uncomfortable about doing *k where k is a
*datastore.Key (since the SDK never handles a dereferenced Key object). I did
have some superfluous &'s below though, which I've removed.

+	*datastore.Key
+}
+
+var _ gae.DSKey = dsKeyImpl{}
+
+func (k dsKeyImpl) Equal(other gae.DSKey) bool { return k.Key.Equal(f2r(other)) }
+func (k dsKeyImpl) Parent() gae.DSKey          { return &dsKeyImpl{k.Key.Parent()} }

[Vadim Sh., 2015/07/14 00:12:37]

f2r(k.Key.Parent())?

[iannucci, 2015/07/14 01:07:46]

r2f, but yes

+func (k dsKeyImpl) Root() gae.DSKey            { return helper.DSKeyRoot(k) }
+func (k dsKeyImpl) Valid(ns string, allowSpecial bool) bool {
+	return helper.DSKeyValid(k, ns, allowSpecial)
+}
+
+func r2f(k *datastore.Key) gae.DSKey {
+	return &dsKeyImpl{k}
+}
+
+func r2fe(k *datastore.Key, err error) (gae.DSKey, error) {
+	if err != nil {

[Vadim Sh., 2015/07/14 00:12:37]

huh?

[iannucci, 2015/07/14 01:07:46]

it's for wrapping methods which return (*datastore.Key, error). added comment.

+		return nil, err
+	}
+	return r2f(k), nil
+}
+
+func f2r(k gae.DSKey) *datastore.Key {
+	return k.(dsKeyImpl).Key
+}
+
+func mr2f(ks []*datastore.Key) []gae.DSKey {

[Vadim Sh., 2015/07/14 00:12:37]

these are very cryptic names :)

[iannucci, 2015/07/14 01:07:46]

yeah, added comments

+	ret := make([]gae.DSKey, len(ks))
+	for i, k := range ks {
+		ret[i] = r2f(k)
+	}
+	return ret
+}
+
+func mf2r(ks []gae.DSKey) []*datastore.Key {
+	ret := make([]*datastore.Key, len(ks))
+	for i, k := range ks {
+		ret[i] = f2r(k)
+	}
+	return ret
+}