[SyncFS] Make MetadataDatabase operations synchronous

chrome/browser/sync_file_system/drive_backend/metadata_database.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_METADATA_DATABASE_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_METADATA_DATABASE_H_
 
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
 
-#include "base/callback_forward.h"
 #include "base/containers/hash_tables.h"
 #include "base/containers/scoped_ptr_hash_map.h"
+#include "base/files/file_path.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
 #include "base/sequence_checker.h"
 #include "base/values.h"
 #include "chrome/browser/sync_file_system/drive_backend/tracker_id_set.h"
-#include "chrome/browser/sync_file_system/sync_callbacks.h"
 #include "chrome/browser/sync_file_system/sync_status_code.h"
 
-namespace base {
-class FilePath;
-class SequencedTaskRunner;
-class SingleThreadTaskRunner;
-}
-
 namespace leveldb {
 class Env;
 }
 
 namespace google_apis {
 class ChangeResource;
 class FileResource;
 class ResourceEntry;
 }
 
@@ skipping 66 matching lines @@
 //
 //   - If multiple trackers have the same parent tracker and same title, they
 //     must not have same |file_id|, and at most one of them may be active.
 //   - If multiple trackers have the same |file_id|, at most one of them may be
 //     active.
 //
 class MetadataDatabase {
  public:
   typedef std::vector<std::string> FileIDList;
 
-  typedef base::Callback<
-      void(SyncStatusCode status, scoped_ptr<MetadataDatabase> instance)>
-      CreateCallback;
-
   enum ActivationStatus {
     ACTIVATION_PENDING,
     ACTIVATION_FAILED_ANOTHER_ACTIVE_TRACKER,
   };
 
   enum UpdateOption {
     UPDATE_TRACKER_FOR_UNSYNCED_FILE,
     UPDATE_TRACKER_FOR_SYNCED_FILE,
   };
 
   // The entry point of the MetadataDatabase for production code.
   // If |env_override| is non-NULL, internal LevelDB uses |env_override| instead
   // of leveldb::Env::Default().  Use leveldb::MemEnv in test code for faster
   // testing.
-  static void Create(
+  static scoped_ptr<MetadataDatabase> Create(
       const base::FilePath& database_path,
       leveldb::Env* env_override,
-      const CreateCallback& callback);
+      SyncStatusCode* status);
   static SyncStatusCode CreateForTesting(
       scoped_ptr<LevelDBWrapper> db,
       bool enable_on_disk_index,
       scoped_ptr<MetadataDatabase>* metadata_database_out);
 
   ~MetadataDatabase();
 
   static void ClearDatabase(scoped_ptr<MetadataDatabase> metadata_database);
 
   int64 GetLargestFetchedChangeID() const;
@@ skipping 23 matching lines @@
   int64 GetLargestKnownChangeID() const;
   void UpdateLargestKnownChangeID(int64 change_id);
 
   // Populates empty database with initial data.
   // Adds a file metadata and a file tracker for |sync_root_folder|, and adds
   // file metadata and file trackers for each |app_root_folders|.
   // Newly added tracker for |sync_root_folder| is active and non-dirty.
   // Newly added trackers for |app_root_folders| are inactive and non-dirty.
   // Trackers for |app_root_folders| are not yet registered as app-roots, but
   // are ready to register.
-  void PopulateInitialData(
+  SyncStatusCode PopulateInitialData(
       int64 largest_change_id,
       const google_apis::FileResource& sync_root_folder,
-      const ScopedVector<google_apis::FileResource>& app_root_folders,
-      const SyncStatusCallback& callback);
+      const ScopedVector<google_apis::FileResource>& app_root_folders);
 
   // Returns true if the folder associated to |app_id| is enabled.
   bool IsAppEnabled(const std::string& app_id) const;
 
   // Registers existing folder as the app-root for |app_id|.  The folder
   // must be an inactive folder that does not yet associated to any App.
   // This method associates the folder with |app_id| and activates it.
-  void RegisterApp(const std::string& app_id,
-                   const std::string& folder_id,
-                   const SyncStatusCallback& callback);
+  SyncStatusCode RegisterApp(const std::string& app_id,
+                             const std::string& folder_id);
 
   // Inactivates the folder associated to the app to disable |app_id|.
   // Does nothing if |app_id| is already disabled.
-  void DisableApp(const std::string& app_id,
-                  const SyncStatusCallback& callback);
+  SyncStatusCode DisableApp(const std::string& app_id);
 
   // Activates the folder associated to |app_id| to enable |app_id|.
   // Does nothing if |app_id| is already enabled.
-  void EnableApp(const std::string& app_id,
-                 const SyncStatusCallback& callback);
+  SyncStatusCode EnableApp(const std::string& app_id);
 
   // Unregisters the folder as the app-root for |app_id|.  If |app_id| does not
   // exist, does nothing.  The folder is left as an inactive regular folder.
   // Note that the inactivation drops all descendant files since they are no
   // longer reachable from sync-root via active folder or app-root.
-  void UnregisterApp(const std::string& app_id,
-                     const SyncStatusCallback& callback);
+  SyncStatusCode UnregisterApp(const std::string& app_id);
 
   // Finds the app-root folder for |app_id|.  Returns true if exists.
   // Copies the result to |tracker| if it is non-NULL.
   bool FindAppRootTracker(const std::string& app_id,
                           FileTracker* tracker) const;
 
   // Finds the file identified by |file_id|.  Returns true if the file is found.
   // Copies the metadata identified by |file_id| into |file| if exists and
   // |file| is non-NULL.
   bool FindFileByFileID(const std::string& file_id, FileMetadata* file) const;
@@ skipping 33 matching lines @@
   // Otherwise, assigns the nearest active ancestor to |full_path| to |tracker|.
   // Also, assigns the full path of |tracker| to |path|.
   bool FindNearestActiveAncestor(const std::string& app_id,
                                  const base::FilePath& full_path,
                                  FileTracker* tracker,
                                  base::FilePath* path) const;
 
   // Updates database by |changes|.
   // Marks each tracker for modified file as dirty and adds new trackers if
   // needed.
-  void UpdateByChangeList(int64 largest_change_id,
-                          ScopedVector<google_apis::ChangeResource> changes,
-                          const SyncStatusCallback& callback);
+  SyncStatusCode UpdateByChangeList(
+      int64 largest_change_id,
+      ScopedVector<google_apis::ChangeResource> changes);
 
   // Updates database by |resource|.
   // Marks each tracker for modified file as dirty and adds new trackers if
   // needed.
-  void UpdateByFileResource(const google_apis::FileResource& resource,
-                            const SyncStatusCallback& callback);
-  void UpdateByFileResourceList(
-      ScopedVector<google_apis::FileResource> resources,
-      const SyncStatusCallback& callback);
+  SyncStatusCode UpdateByFileResource(
+      const google_apis::FileResource& resource);
+  SyncStatusCode UpdateByFileResourceList(
+      ScopedVector<google_apis::FileResource> resources);
 
-  void UpdateByDeletedRemoteFile(const std::string& file_id,
-                                 const SyncStatusCallback& callback);
-  void UpdateByDeletedRemoteFileList(const FileIDList& file_ids,
-                                     const SyncStatusCallback& callback);
+  SyncStatusCode UpdateByDeletedRemoteFile(const std::string& file_id);
+  SyncStatusCode UpdateByDeletedRemoteFileList(const FileIDList& file_ids);
 
   // Adds new FileTracker and FileMetadata.  The database must not have
   // |resource| beforehand.
   // The newly added tracker under |parent_tracker_id| is active and non-dirty.
   // Deactivates existing active tracker if exists that has the same title and
   // parent_tracker to the newly added tracker.
-  void ReplaceActiveTrackerWithNewResource(
+  SyncStatusCode ReplaceActiveTrackerWithNewResource(
       int64 parent_tracker_id,
-      const google_apis::FileResource& resource,
-      const SyncStatusCallback& callback);
+      const google_apis::FileResource& resource);
 
   // Adds |child_file_ids| to |folder_id| as its children.
   // This method affects the active tracker only.
   // If the tracker has no further change to sync, unmarks its dirty flag.
-  void PopulateFolderByChildList(const std::string& folder_id,
-                                 const FileIDList& child_file_ids,
-                                 const SyncStatusCallback& callback);
+  SyncStatusCode PopulateFolderByChildList(const std::string& folder_id,
+                                           const FileIDList& child_file_ids);
 
   // Updates |synced_details| of the tracker with |updated_details|.
-  void UpdateTracker(int64 tracker_id,
-                     const FileDetails& updated_details,
-                     const SyncStatusCallback& callback);
+  SyncStatusCode UpdateTracker(int64 tracker_id,
+                               const FileDetails& updated_details);
 
   // Activates a tracker identified by |parent_tracker_id| and |file_id| if the
   // tracker can be activated without inactivating other trackers that have the
   // same |file_id| but different paths.
   // If |file_id| has another active tracker, the function returns
   // ACTIVATION_FAILED_ANOTHER_ACTIVE_TRACKER and does not invoke |callback|.
   // If there is another active tracker that has the same path but different
   // |file_id|, inactivates the tracker.
   // In success case, returns ACTIVATION_PENDING and invokes |callback| upon
   // completion.
   //
   // The tracker to be activated must:
   //  - have a tracked metadata in the database,
   //  - have |synced_details| with valid |title|.
   ActivationStatus TryActivateTracker(int64 parent_tracker_id,
                                       const std::string& file_id,
-                                      const SyncStatusCallback& callback);
+                                      SyncStatusCode* status);
 
   // Changes the priority of the tracker to low.
   void DemoteTracker(int64 tracker_id);
   bool PromoteDemotedTrackers();
   void PromoteDemotedTracker(int64 tracker_id);
 
   // Returns true if there is a normal priority dirty tracker.
   // Assigns the dirty tracker if exists and |tracker| is non-NULL.
   bool GetDirtyTracker(FileTracker* tracker) const;
 
   // Returns true if there is a low priority dirty tracker.
   bool HasDemotedDirtyTracker() const;
 
   bool HasDirtyTracker() const;
   size_t CountDirtyTracker() const;
   size_t CountFileMetadata() const;
   size_t CountFileTracker() const;
 
   bool GetMultiParentFileTrackers(std::string* file_id,
                                   TrackerIDSet* trackers);
   bool GetConflictingTrackers(TrackerIDSet* trackers);
 
   // Sets |app_ids| to a list of all registered app ids.
   void GetRegisteredAppIDs(std::vector<std::string>* app_ids);
 
   // Clears dirty flag of trackers that can be cleared without external
   // interactien.
-  void SweepDirtyTrackers(const std::vector<std::string>& file_ids,
-                          const SyncStatusCallback& callback);
+  SyncStatusCode SweepDirtyTrackers(const std::vector<std::string>& file_ids);
 
  private:
   friend class MetadataDatabaseTest;
 
   MetadataDatabase(const base::FilePath& database_path,
                    bool enable_on_disk_index,
                    leveldb::Env* env_override);
   SyncStatusCode Initialize();
 
   // Database manipulation methods.
@@ skipping 21 matching lines @@
   bool HasDisabledAppRoot(const FileTracker& tracker) const;
   bool HasActiveTrackerForFileID(const std::string& file_id) const;
   bool HasActiveTrackerForPath(int64 parent_tracker,
                                const std::string& title) const;
 
   void RemoveUnneededTrackersForMissingFile(const std::string& file_id);
   void UpdateByFileMetadata(const tracked_objects::Location& from_where,
                             scoped_ptr<FileMetadata> file,
                             UpdateOption option);
 
-  void WriteToDatabase(const SyncStatusCallback& callback);
+  SyncStatusCode WriteToDatabase();
 
   bool HasNewerFileMetadata(const std::string& file_id, int64 change_id);
 
   scoped_ptr<base::ListValue> DumpTrackers();
   scoped_ptr<base::ListValue> DumpMetadata();
 
   void AttachSyncRoot(const google_apis::FileResource& sync_root_folder);
   void AttachInitialAppRoot(const google_apis::FileResource& app_root_folder);
 
   void ForceActivateTrackerByPath(int64 parent_tracker_id,
@@ skipping 14 matching lines @@
 
   base::WeakPtrFactory<MetadataDatabase> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MetadataDatabase);
 };
 
 }  // namespace drive_backend
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_METADATA_DATABASE_H_