Use SetFinalizer to avoid leaking Snapshots.

go/src/infra/gae/libs/wrapper/memory/gkvlite_utils.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 memory
 
 import (
         "bytes"
+        "runtime"
         "sync"
 
         "github.com/luci/gkvlite"
 )
 
 func gkvCollide(o, n *memCollection, f func(k, ov, nv []byte)) {
         oldItems, newItems := make(chan *gkvlite.Item), make(chan *gkvlite.Item)
         walker := func(c *memCollection, ch chan<- *gkvlite.Item, wg *sync.WaitGroup) {
                 defer close(ch)
                 defer wg.Done()
@@ skipping 49 matching lines @@
 
 func newMemStore() *memStore {
         ret, err := gkvlite.NewStore(nil)
         if err != nil {
                 panic(err)
         }
         return (*memStore)(ret)
 }
 
 func (ms *memStore) Snapshot() *memStore {
-        return (*memStore)((*gkvlite.Store)(ms).Snapshot())
+        ret := (*memStore)((*gkvlite.Store)(ms).Snapshot())
+        runtime.SetFinalizer((*gkvlite.Store)(ret), func(s *gkvlite.Store) {
+                go s.Close()
+        })
+        return ret
 }
 
 func (ms *memStore) MakePrivateCollection(cmp gkvlite.KeyCompare) *memCollection {
         return (*memCollection)((*gkvlite.Store)(ms).MakePrivateCollection(cmp))
 }
 
 func (ms *memStore) GetCollection(name string) *memCollection {
         return (*memCollection)((*gkvlite.Store)(ms).GetCollection(name))
 }
 
@@ skipping 53 matching lines @@
         }
 }
 
 func (mc *memCollection) GetTotals() (numItems, numBytes uint64) {
         numItems, numBytes, err := (*gkvlite.Collection)(mc).GetTotals()
         if err != nil {
                 panic(err)
         }
         return
 }