FileSystem: Prevent iterator from being deleted after database.

storage/browser/fileapi/sandbox_origin_database.cc

 // Copyright (c) 2012 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.
 
 #include "storage/browser/fileapi/sandbox_origin_database.h"
 
 #include <stdint.h>
 
 #include <set>
 #include <utility>
@@ skipping 313 matching lines @@
   std::string number_string;
   leveldb::Status status =
       db_->Get(leveldb::ReadOptions(), LastPathKey(), &number_string);
   if (status.ok())
     return base::StringToInt(number_string, number);
   if (!status.IsNotFound()) {
     HandleError(FROM_HERE, status);
     return false;
   }
   // Verify that this is a totally new database, and initialize it.
-  scoped_ptr<leveldb::Iterator> iter(db_->NewIterator(leveldb::ReadOptions()));
-  iter->SeekToFirst();
-  if (iter->Valid()) {  // DB was not empty, but had no last path number!
-    LOG(ERROR) << "File system origin database is corrupt!";
-    return false;
+  {
+    // Scope the iterator to ensure it is deleted before database is closed.
+    scoped_ptr<leveldb::Iterator> iter(
+        db_->NewIterator(leveldb::ReadOptions()));
+    iter->SeekToFirst();
+    if (iter->Valid()) {  // DB was not empty, but had no last path number!
+      LOG(ERROR) << "File system origin database is corrupt!";
+      return false;
+    }
   }
   // This is always the first write into the database.  If we ever add a
   // version number, they should go in in a single transaction.
-  status =
-      db_->Put(leveldb::WriteOptions(), LastPathKey(), std::string("-1"));
+  status = db_->Put(leveldb::WriteOptions(), LastPathKey(), std::string("-1"));
   if (!status.ok()) {
     HandleError(FROM_HERE, status);
     return false;
   }
   *number = -1;
   return true;
 }
 
 }  // namespace storage