Add 'user friendly' datastore API.

service/datastore/pls.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
+package datastore
 
 import (
         "reflect"
 )
 
 // GetPLS resolves o into a PropertyLoadSaver. o must be a pointer to a
 // struct of some sort.
 func GetPLS(o interface{}) PropertyLoadSaver {
         v := reflect.ValueOf(o)
         if v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct {
                 return &structPLS{c: &structCodec{problem: ErrInvalidEntityType}}
         }
         v = v.Elem()
-        t := v.Type()
+        c := getCodec(v.Type())
+        return &structPLS{v, c}
+}
 
+func getCodec(structType reflect.Type) *structCodec {
         structCodecsMutex.RLock()
-        if c, ok := structCodecs[t]; ok {
-                structCodecsMutex.RUnlock()
-                return &structPLS{v, c}
+        c, ok := structCodecs[structType]
+        structCodecsMutex.RUnlock()
+        if ok {
+                return c
         }
-        structCodecsMutex.RUnlock()
 
         structCodecsMutex.Lock()
         defer structCodecsMutex.Unlock()
-        return &structPLS{v, getStructCodecLocked(t)}
+        return getStructCodecLocked(structType)
 }