Refactor multiarg, split MGS/PLS.

service/datastore/datastore.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package datastore
 
 import (
         "fmt"
         "io"
         "io/ioutil"
@@ skipping 41 matching lines @@
         return NewKeyToks(d.aid, d.ns, toks)
 }
 
 // PopulateKey loads key into obj.
 //
 // obj is any object that Interface.Get is able to accept.
 //
 // This method will panic if obj is an invalid datastore model. If the key could
 // not be applied to the object, nothing will happen.
 func PopulateKey(obj interface{}, key *Key) {
-        pls := getMGS(obj)
-        if !pls.SetMeta("key", key) {
+        populateKeyMGS(getMGS(obj), key)
+}
+
+func populateKeyMGS(mgs MetaGetterSetter, key *Key) {
+        if !mgs.SetMeta("key", key) {
                 lst := key.LastTok()
                 if lst.StringID != "" {
-                        pls.SetMeta("id", lst.StringID)
+                        mgs.SetMeta("id", lst.StringID)
                 } else {
-                        pls.SetMeta("id", lst.IntID)
+                        mgs.SetMeta("id", lst.IntID)
                 }
-                pls.SetMeta("kind", lst.Kind)
-                pls.SetMeta("parent", key.Parent())
+                mgs.SetMeta("kind", lst.Kind)
+                mgs.SetMeta("parent", key.Parent())
         }
 }
 
 func checkMultiSliceType(v interface{}) error {
         if reflect.TypeOf(v).Kind() == reflect.Slice {
                 return nil
         }
         return fmt.Errorf("argument must be a slice, not %T", v)
 
 }
@@ skipping 429 matching lines @@
                 currentDir = filepath.Dir(currentDir)
         }
 }
 
 func filterStop(err error) error {
         if err == Stop {
                 err = nil
         }
         return err
 }