Fetch incremental updates. Store new state in V4Store.

components/safe_browsing_db/v4_database.h

 // 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.
 
 #ifndef COMPONENTS_SAFE_BROWSING_DB_V4_DATABASE_H_
 #define COMPONENTS_SAFE_BROWSING_DB_V4_DATABASE_H_
 
+#include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/sequenced_task_runner.h"
 #include "base/single_thread_task_runner.h"
 #include "components/safe_browsing_db/v4_protocol_manager_util.h"
 #include "components/safe_browsing_db/v4_store.h"
 
 namespace safe_browsing {
 
 class V4Database;
 
 typedef base::Callback<void(std::unique_ptr<V4Database>)>
     NewDatabaseReadyCallback;
 
-// This defines a hash_map that is used to create the backing files for the
-// stores that contain the hash-prefixes. The map key identifies the list that
-// we're interested in and the value represents the ASCII file-name that'll be
-// created on-disk to store the hash-prefixes for that list. This file is
-// created inside the user's profile directory.
-// For instance, the UpdateListIdentifier could be for URL expressions for UwS
-// on Windows platform, and the corresponding file on disk could be named:
-// "uws_win_url.store"
-typedef base::hash_map<UpdateListIdentifier, std::string> StoreFileNameMap;
+// This callback is scheduled once the database has finished processing the
+// update requests for all stores and is ready to process the next set of update
+// requests.
+typedef base::Callback<void()> DatabaseUpdatedCallback;
 
 // This hash_map maps the UpdateListIdentifiers to their corresponding in-memory
 // stores, which contain the hash prefixes for that UpdateListIdentifier as well
 // as manage their storage on disk.
 typedef base::hash_map<UpdateListIdentifier, std::unique_ptr<V4Store>> StoreMap;
 
 // Factory for creating V4Database. Tests implement this factory to create fake
 // databases for testing.
 class V4DatabaseFactory {
  public:
   virtual ~V4DatabaseFactory() {}
   virtual V4Database* CreateV4Database(
       const scoped_refptr<base::SequencedTaskRunner>& db_task_runner,
       const base::FilePath& base_dir_path,
       const StoreFileNameMap& store_file_name_map) = 0;
 };
 
 // The on-disk databases are shared among all profiles, as it doesn't contain
 // user-specific data. This object is not thread-safe, i.e. all its methods
 // should be used on the same thread that it was created on, unless specified
 // otherwise.
 // The hash-prefixes of each type are managed by a V4Store (including saving to
 // and reading from disk).
 // The V4Database serves as a single place to manage all the V4Stores.
 class V4Database {
  public:
   // Factory method to create a V4Database. It creates the database on the
-  // provided |db_task_runner|. When the database creation is complete, it calls
-  // the NewDatabaseReadyCallback on the same thread as it was called.
+  // provided |db_task_runner| containing stores in |store_file_name_map|. When
+  // the database creation is complete, it runs the NewDatabaseReadyCallback on
+  // the same thread as it was called.
   static void Create(
       const scoped_refptr<base::SequencedTaskRunner>& db_task_runner,
       const base::FilePath& base_path,
       const StoreFileNameMap& store_file_name_map,
+      DatabaseUpdatedCallback db_updated_callback,
       NewDatabaseReadyCallback callback);
 
   // Destroys the provided v4_database on its task_runner since this may be a
   // long operation.
   static void Destroy(std::unique_ptr<V4Database> v4_database);
 
   virtual ~V4Database();
 
+  // Updates the stores with the response received from the SafeBrowsing service
+  // and calls the db_updated_callback_ when done.
+  void ApplyUpdate(const std::vector<ListUpdateResponse>& response);
+
+  // Returns the current state of each of the stores being managed.
+  std::unique_ptr<StoreStateMap> GetStoreStateMap();
+
   // Deletes the current database and creates a new one.
   virtual bool ResetDatabase();
 
  protected:
   V4Database(const scoped_refptr<base::SequencedTaskRunner>& db_task_runner,
-             std::unique_ptr<StoreMap> store_map);
+             std::unique_ptr<StoreMap> store_map,
+             DatabaseUpdatedCallback db_updated_callback);
 
  private:
   friend class SafeBrowsingV4DatabaseTest;
   FRIEND_TEST_ALL_PREFIXES(SafeBrowsingV4DatabaseTest,
                            TestSetupDatabaseWithFakeStores);
   FRIEND_TEST_ALL_PREFIXES(SafeBrowsingV4DatabaseTest,
                            TestSetupDatabaseWithFakeStoresFailsReset);
+  FRIEND_TEST_ALL_PREFIXES(SafeBrowsingV4DatabaseTest,
+                           TestApplyUpdateWithNewStates);
+  FRIEND_TEST_ALL_PREFIXES(SafeBrowsingV4DatabaseTest,
+                           TestApplyUpdateWithNoNewState);
+  FRIEND_TEST_ALL_PREFIXES(SafeBrowsingV4DatabaseTest,
+                           TestApplyUpdateWithEmptyUpdate);
 
   // Makes the passed |factory| the factory used to instantiate a V4Store. Only
   // for tests.
   static void RegisterStoreFactoryForTest(V4StoreFactory* factory) {
     factory_ = factory;
   }
 
   // Factory method to create a V4Database. When the database creation is
   // complete, it calls the NewDatabaseReadyCallback on |callback_task_runner|.
   static void CreateOnTaskRunner(
       const scoped_refptr<base::SequencedTaskRunner>& db_task_runner,
       const base::FilePath& base_path,
       const StoreFileNameMap& store_file_name_map,
+      DatabaseUpdatedCallback db_updated_callback,
       const scoped_refptr<base::SingleThreadTaskRunner>& callback_task_runner,
       NewDatabaseReadyCallback callback);
 
+  // Callback called when a new store has been created and is ready to be used.
+  // This method updates the store_map_ to point to the new store, which causes
+  // the old store to get deleted.
+  void UpdatedStoreReady(UpdateListIdentifier identifier,
+                         std::unique_ptr<V4Store> store);
+
   const scoped_refptr<base::SequencedTaskRunner> db_task_runner_;
 
   // Map of UpdateListIdentifier to the V4Store.
   const std::unique_ptr<StoreMap> store_map_;
 
+  DatabaseUpdatedCallback db_updated_callback_;
+
   // The factory that controls the creation of V4Store objects.
   static V4StoreFactory* factory_;
 
+  // The number of stores for which the update request is pending. When this
+  // goes down to 0, that indicates that the database has updated all the stores
+  // that needed updating and is ready for the next update. It should only be
+  // accessed on the IO thread.
+  int pending_store_updates_;
+
   DISALLOW_COPY_AND_ASSIGN(V4Database);
 };
 
 }  // namespace safe_browsing
 
 #endif  // COMPONENTS_SAFE_BROWSING_DB_V4_DATABASE_H_