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

components/safe_browsing_db/v4_database.cc

Index: components/safe_browsing_db/v4_database.cc
diff --git a/components/safe_browsing_db/v4_database.cc b/components/safe_browsing_db/v4_database.cc
index 3c1cf1c51a64a8a85df58616ccd8e5c6a0e781db..9d0312438d4b00ef6f34748651141a4a4b125277 100644
--- a/components/safe_browsing_db/v4_database.cc
+++ b/components/safe_browsing_db/v4_database.cc
@@ -168,4 +168,21 @@ std::unique_ptr<StoreStateMap> V4Database::GetStoreStateMap() {
   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