Refactor a bit.

service/rawdatastore/types.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 rawdatastore
+
+// ByteString is a short byte slice (up to 1500 bytes) that can be indexed.
+type ByteString []byte
+
+// GeoPoint represents a location as latitude/longitude in degrees.
+//
+// You probably shouldn't use these, but their inclusion here is so that the
+// RawDatastore can interact (and round-trip) correctly with other datastore API
+// implementations.
+type GeoPoint struct {
+        Lat, Lng float64
+}
+
+// Valid returns whether a GeoPoint is within [-90, 90] latitude and [-180,
+// 180] longitude.
+func (g GeoPoint) Valid() bool {
+        return -90 <= g.Lat && g.Lat <= 90 && -180 <= g.Lng && g.Lng <= 180
+}
+
+// TransactionOptions are the options for running a transaction.
+type TransactionOptions struct {
+        // XG is whether the transaction can cross multiple entity groups. In
+        // comparison, a single group transaction is one where all datastore keys
+        // used have the same root key. Note that cross group transactions do not
+        // have the same behavior as single group transactions. In particular, it
+        // is much more likely to see partially applied transactions in different
+        // entity groups, in global queries.
+        // It is valid to set XG to true even if the transaction is within a
+        // single entity group.
+        XG bool
+        // Attempts controls the number of retries to perform when commits fail
+        // due to a conflicting transaction. If omitted, it defaults to 3.
+        Attempts int
+}