Call batch/incremental fetch with more strict conditions

chrome/browser/sync_file_system/drive_file_sync_service.h

 // Copyright (c) 2012 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_FILE_SYNC_SERVICE_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_FILE_SYNC_SERVICE_H_
 
 #include <deque>
 #include <map>
 #include <set>
@@ skipping 323 matching lines @@
   bool GetPendingChangeForFileSystemURL(const fileapi::FileSystemURL& url,
                                         RemoteChange* change) const;
 
   // A wrapper implementation to GDataErrorCodeToSyncStatusCode which returns
   // authentication error if the user is not signed in.
   fileapi::SyncStatusCode GDataErrorCodeToSyncStatusCodeWrapper(
       google_apis::GDataErrorCode error) const;
 
   base::FilePath temporary_file_dir_;
 
+  // May start batch sync or incremental sync.
+  // This immediately returns if:
+  // - Another task is running (i.e. task_ is null), or
+  // - The service state is DISABLED.
+  //
+  // This calls:
+  // - StartBatchSyncForOrigin() if it has any pending batch sync origins, or
+  // - FetchChangesForIncrementalSync() otherwise.
+  //
+  // These two methods are called only from this method.
+  void MaybeStartFetchChanges();
+
   void FetchChangesForIncrementalSync();
   void DidFetchChangesForIncrementalSync(
       scoped_ptr<TaskToken> token,
       bool has_new_changes,
       google_apis::GDataErrorCode error,
       scoped_ptr<google_apis::ResourceList> changes);
   bool GetOriginForEntry(const google_apis::ResourceEntry& entry, GURL* origin);
   void SchedulePolling();
+  void OnPollingTimerFired();
   void UpdatePollingDelay(int64 new_delay_sec);
   void RegisterDriveNotifications();
   void SetPushNotificationEnabled(syncer::InvalidatorState state);
 
   scoped_ptr<DriveMetadataStore> metadata_store_;
   scoped_ptr<DriveFileSyncClient> sync_client_;
 
   Profile* profile_;
   fileapi::SyncStatusCode last_operation_status_;
   std::deque<base::Closure> pending_tasks_;
@@ skipping 25 matching lines @@
 
   // True when Drive File Sync Service is registered for Drive notifications.
   bool push_notification_registered_;
   // True once the first drive notification is received with OK state.
   bool push_notification_enabled_;
   // Timer to trigger fetching changes for incremental sync.
   base::OneShotTimer<DriveFileSyncService> polling_timer_;
   // If polling_delay_seconds_ is negative (<0) the timer won't start.
   int64 polling_delay_seconds_;
 
-  // Is set to true while the service is fetching changes for incremental
-  // sync. Polling will be disabled while this is true.
-  bool is_fetching_changes_;
+  // Is set to true when there's a fair possibility that we have some
+  // remote changes that haven't been fetched yet.
+  //
+  // This flag is set when:
+  // - This gets invalidation notification,
+  // - The service is authenticated or becomes online, and
+  // - The polling timer is fired.
+  //
+  // This flag is cleared when:
+  // - A batch or incremental sync has been started, and
+  // - When all pending batch sync tasks have been finished.
+  bool may_have_unfetched_changes_;
 
   ObserverList<Observer> service_observers_;
   ObserverList<FileStatusObserver> file_status_observers_;
 
   // Use WeakPtrFactory instead of SupportsWeakPtr to revoke the weak pointer
   // in |token_|.
   base::WeakPtrFactory<DriveFileSyncService> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DriveFileSyncService);
 };
 
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_FILE_SYNC_SERVICE_H_