PVer4: V4Database: Return stores that have a hash prefix for a given full hash

components/safe_browsing_db/v4_database.cc

 // Copyright 2016 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 <memory>
 
 #include "base/callback.h"
 #include "base/debug/leak_annotations.h"
 #include "base/files/file_util.h"
 #include "base/memory/ptr_util.h"
@@ skipping 150 matching lines @@
 
 std::unique_ptr<StoreStateMap> V4Database::GetStoreStateMap() {
   std::unique_ptr<StoreStateMap> store_state_map =
       base::MakeUnique<StoreStateMap>();
   for (const auto& store_map_iter : *store_map_) {
     (*store_state_map)[store_map_iter.first] = store_map_iter.second->state();
   }
   return store_state_map;
 }
 
+void V4Database::GetStoresMatchingFullHash(
+    const FullHash& full_hash,
+    const base::hash_set<UpdateListIdentifier>& stores_to_look,
+    MatchedHashPrefixMap* matched_hash_prefix_map) {
+  for (const auto& store_pair : *store_map_) {

[Nathan Parker, 2016/07/20 20:44:13]

This is sort of NxM complexity with two loops (for loop, and count()).  Instead,
just iterate over stores_to_look and use store_map->find(id), since it is a map.

[vakh (use Gerrit instead), 2016/07/20 21:10:27]

Done.

+    const UpdateListIdentifier& identifier = store_pair.first;
+    if (stores_to_look.count(identifier) == 1) {
+      const std::unique_ptr<V4Store>& store = store_pair.second;
+
+      HashPrefix hash_prefix = store->GetMatchingHashPrefix(full_hash);
+      if (!hash_prefix.empty()) {
+        (*matched_hash_prefix_map)[identifier] = hash_prefix;
+      }
+    }
+  }
+}
+
 }  // namespace safe_browsing