[SyncFS] Implement SyncEngineInitializer

chrome/browser/sync_file_system/drive_backend/sync_engine_initializer.h

 // Copyright 2013 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 CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_ENGINE_INITIALIZER_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_ENGINE_INITIALIZER_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
 #include "base/sequenced_task_runner.h"
+#include "chrome/browser/google_apis/drive_common_callbacks.h"
+#include "chrome/browser/google_apis/gdata_errorcode.h"
 #include "chrome/browser/sync_file_system/sync_callbacks.h"
 #include "chrome/browser/sync_file_system/sync_task.h"
 
 namespace drive {
-class DriveAPIService;
+class DriveServiceInterface;
+}
+
+namespace google_apis {
+class AboutResource;
+class ResourceEntry;
+class ResourceList;
 }
 
 namespace sync_file_system {
 namespace drive_backend {
 
 class MetadataDatabase;
 
+// This class performs initializion sequence of SyncEngine.
+//
+// After initialize sequence completed, the Database must have
+//  - Largest change ID,
+//  - Sync-root folder and its tracker,
+//  - All children of sync-root folder that have inactive and non-dirty
+//    trackers.
+//
+// The initialization sequence is:
+//  - Open database and load its contents,
+//  - If the database is already populated, complete the sequence.
+//  - Get AboutResource to get the largest change ID and the Drive root folder
+//    ID.
+//  - Find the remote sync-root folder, whose title is
+//    "Chrome Syncable FileSystem" and has no parent.
+//    Note that if the initialization is interrupted by the browser restart or
+//    an error, the sequence leaves the folder in the Drive root folder.  So, if
+//    we find the folder in the Drive root folder, handle it as the sync-root
+//    folder.
+//  - Create the remote sync-root folder if we don't have.
+//  - Detach the remote sync-root folder from its parent if it has.
+//  - Fetch the folder contents of the remote sync-root folder.
+//    The contents are likely registered as app-root folders, but handle them
+//    as regular inactive folders until they are registered explicitly.
+//  - Populate database with the largest change ID, the sync-root folder and
+//    its contents.
+//
 class SyncEngineInitializer : public SyncTask {
  public:
   SyncEngineInitializer(base::SequencedTaskRunner* task_runner,
-                        drive::DriveAPIService* drive_api,
+                        drive::DriveServiceInterface* drive_service,
                         const base::FilePath& database_path);
   virtual ~SyncEngineInitializer();
   virtual void Run(const SyncStatusCallback& callback) OVERRIDE;
 
+  scoped_ptr<MetadataDatabase> PassMetadataDatabase();
+
  private:
+  typedef base::Callback<void(const SyncStatusCallback& callback)> Task;
+
   void DidCreateMetadataDatabase(const SyncStatusCallback& callback,
                                  SyncStatusCode status,
                                  scoped_ptr<MetadataDatabase> instance);
 
+  void GetAboutResource(const SyncStatusCallback& callback);
+  void DidGetAboutResource(
+      const SyncStatusCallback& callback,
+      google_apis::GDataErrorCode error,
+      scoped_ptr<google_apis::AboutResource> about_resource);
+  void FindSyncRoot(const SyncStatusCallback& callback);
+  void DidFindSyncRoot(const SyncStatusCallback& callback,
+                       google_apis::GDataErrorCode error,
+                       scoped_ptr<google_apis::ResourceList> resource_list);
+  void CreateSyncRoot(const SyncStatusCallback& callback);
+  void DidCreateSyncRoot(const SyncStatusCallback& callback,
+                         google_apis::GDataErrorCode error,
+                         scoped_ptr<google_apis::ResourceEntry> entry);
+  void DetachSyncRoot(const SyncStatusCallback& callback);
+  void DidDetachSyncRoot(const SyncStatusCallback& callback,
+                         google_apis::GDataErrorCode error);
+  void ListAppRootFolders(const SyncStatusCallback& callback);
+  void DidListAppRootFolders(
+      const SyncStatusCallback& callback,
+      google_apis::GDataErrorCode error,
+      scoped_ptr<google_apis::ResourceList> resource_list);
+  void PopulateDatabase(const SyncStatusCallback& callback);
+  void DidPopulateDatabase(const SyncStatusCallback& callback,
+                           SyncStatusCode status);
+
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
-  drive::DriveAPIService* drive_api_;
+  drive::DriveServiceInterface* drive_service_;
+  google_apis::CancelCallback cancel_callback_;
   base::FilePath database_path_;
 
   scoped_ptr<MetadataDatabase> metadata_database_;
+  ScopedVector<google_apis::ResourceEntry> app_root_folders_;
+
+  int64 largest_change_id_;
+  std::string root_folder_id_;
+
+  scoped_ptr<google_apis::ResourceEntry> sync_root_folder_;
 
   base::WeakPtrFactory<SyncEngineInitializer> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncEngineInitializer);
 };
 
 }  // namespace drive_backend
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_SYNC_ENGINE_INITIALIZER_H_