Make rawdatastore API safer for writing filters.

service/rawdatastore/context.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
 
 import (
         "golang.org/x/net/context"
 )
 
@@ skipping 24 matching lines @@
 
 // Get gets the Interface implementation from context.
 func Get(c context.Context) Interface {
         ret := getUnfiltered(c)
         if ret == nil {
                 return nil
         }
         for _, f := range getCurFilters(c) {
                 ret = f(c, ret)
         }
-        return ret
+        return applyCheckFilter(c, ret)
 }
 
 // SetFactory sets the function to produce Datastore instances, as returned by
 // the Get method.
 func SetFactory(c context.Context, rdsf Factory) context.Context {
         return context.WithValue(c, rawDatastoreKey, rdsf)
 }
 
 // Set sets the current Datastore object in the context. Useful for testing with
 // a quick mock. This is just a shorthand SetFactory invocation to set a factory
@@ skipping 14 matching lines @@
 func AddFilters(c context.Context, filts ...Filter) context.Context {
         if len(filts) == 0 {
                 return c
         }
         cur := getCurFilters(c)
         newFilts := make([]Filter, 0, len(cur)+len(filts))
         newFilts = append(newFilts, getCurFilters(c)...)
         newFilts = append(newFilts, filts...)
         return context.WithValue(c, rawDatastoreFilterKey, newFilts)
 }