sync/syncable/deferred_on_disk_directory_backing_store.h

// Copyright 2014 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 SYNC_SYNCABLE_DEFERRED_ON_DISK_DIRECTORY_BACKING_STORE_H_
#define SYNC_SYNCABLE_DEFERRED_ON_DISK_DIRECTORY_BACKING_STORE_H_

#include <string>

#include "base/files/file_path.h"
#include "base/macros.h"
#include "sync/base/sync_export.h"
#include "sync/syncable/on_disk_directory_backing_store.h"

namespace syncer {
namespace syncable {

// Store used for backing up user's data before first sync. It creates an
// in-memory store first and switch to on-disk store if SaveChanges() is
// called, which only happens when SyncBackupManager is shut down and a
// syncing backend is to be created. Thus we guarantee that user data is not
// persisted until user is actually going to sync.
class SYNC_EXPORT DeferredOnDiskDirectoryBackingStore
    : public OnDiskDirectoryBackingStore {
 public:
  DeferredOnDiskDirectoryBackingStore(const std::string& dir_name,
                                      const base::FilePath& backing_file_path);
  ~DeferredOnDiskDirectoryBackingStore() override;
  DirOpenResult Load(Directory::MetahandlesMap* handles_map,
                     JournalIndex* delete_journals,
                     MetahandleSet* metahandles_to_purge,
                     Directory::KernelLoadInfo* kernel_load_info) override;
  bool SaveChanges(const Directory::SaveChangesSnapshot& snapshot) override;

 private:
  // Create an on-disk directory backing store. Returns true on success, false
  // on error.
  bool CreateOnDisk();

  // Whether an on-disk directory backing store has been created.
  bool created_on_disk_;

  DISALLOW_COPY_AND_ASSIGN(DeferredOnDiskDirectoryBackingStore);
};

}  // namespace syncable
}  // namespace syncer

#endif  // SYNC_SYNCABLE_DEFERRED_ON_DISK_DIRECTORY_BACKING_STORE_H_