| // Copyright 2016 Google Inc. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef COBALT_STORAGE_SAVEGAME_THREAD_H_ |
| #define COBALT_STORAGE_SAVEGAME_THREAD_H_ |
| |
| #include "base/callback.h" |
| #include "base/memory/scoped_ptr.h" |
| #include "base/synchronization/waitable_event.h" |
| #include "base/threading/thread.h" |
| #include "cobalt/storage/savegame.h" |
| |
| namespace cobalt { |
| namespace storage { |
| |
| // The SavegameThread wraps a Savegame object within its own thread in order to |
| // enable asynchronous writes to the savegame object. |
| class SavegameThread { |
| public: |
| explicit SavegameThread(const Savegame::Options& options); |
| ~SavegameThread(); |
| |
| // Returns the savegame data that existed on disk on startup. This method |
| // should only be called once, as the data will be released after it is |
| // called. |
| scoped_ptr<Savegame::ByteVector> GetLoadedRawBytes(); |
| |
| // Flush data to be written to the savegame file. The write will happen |
| // asynchronously on SavegameThread's I/O thread, so this method will return |
| // immediately. |
| void Flush(scoped_ptr<Savegame::ByteVector> raw_bytes_ptr, |
| const base::Closure& on_flush_complete); |
| |
| private: |
| // Run on the I/O thread to start loading the savegame. |
| void InitializeOnIOThread(); |
| |
| // Called by the destructor, to ensure we destroy certain objects on the |
| // I/O thread. |
| void ShutdownOnIOThread(); |
| |
| // Runs on the I/O thread to write the database to the savegame's persistent |
| // storage. |
| void FlushOnIOThread(scoped_ptr<Savegame::ByteVector> raw_bytes_ptr, |
| const base::Closure& on_flush_complete); |
| |
| // Savegame options passed in to SavegameThread's constructor. |
| Savegame::Options options_; |
| |
| // On initialization, we'll read from the existing savegame file to get |
| // the latest data. This holds a reference to that data, but is released |
| // as soon as GetLoadedRawBytes() is called for the first time. |
| scoped_ptr<Savegame::ByteVector> loaded_raw_bytes_; |
| |
| // The database gets loaded from disk. We block on returning a SQL context |
| // until storage_ready_ is signalled. |
| base::WaitableEvent initialized_; |
| |
| // Storage I/O (savegame reads/writes) runs on a separate thread. |
| scoped_ptr<base::Thread> thread_; |
| |
| // Interface to platform-specific savegame data. |
| scoped_ptr<Savegame> savegame_; |
| |
| // How many flush failures have occurred since the last successful flush. |
| // Flushes (storage writes) may sometimes fail, but we want to make sure |
| // they're not consistently failing. |
| int num_consecutive_flush_failures_; |
| }; |
| |
| } // namespace storage |
| } // namespace cobalt |
| |
| #endif // COBALT_STORAGE_SAVEGAME_THREAD_H_ |