gdata: Implement periodic file system update checks.

chrome/browser/chromeos/gdata/gdata_file_system.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_CHROMEOS_GDATA_GDATA_FILE_SYSTEM_H_
 #define CHROME_BROWSER_CHROMEOS_GDATA_GDATA_FILE_SYSTEM_H_
 #pragma once
 
 #include <sys/stat.h>
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/singleton.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop.h"
 #include "base/platform_file.h"
+#include "base/timer.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/chromeos/gdata/find_entry_delegate.h"
 #include "chrome/browser/chromeos/gdata/gdata_documents_service.h"
 #include "chrome/browser/chromeos/gdata/gdata_files.h"
 #include "chrome/browser/chromeos/gdata/gdata_operation_registry.h"
 #include "chrome/browser/chromeos/gdata/gdata_params.h"
 #include "chrome/browser/chromeos/gdata/gdata_parser.h"
 #include "chrome/browser/chromeos/gdata/gdata_uploader.h"
 #include "chrome/browser/prefs/pref_change_registrar.h"
@@ skipping 137 matching lines @@
   };
 
   // Initializes the object. This function should be called before any
   // other functions.
   virtual void Initialize() = 0;
 
   // Adds and removes the observer.
   virtual void AddObserver(Observer* observer) = 0;
   virtual void RemoveObserver(Observer* observer) = 0;
 
+  // Requests to start periodic updates.
+  // This function only starts periodic updates if it is not yet started.
+  virtual void RequestStartUpdates() = 0;
+
+  // Requests to stop periodic updates.
+  // This function only stops periodic updates if the number of outstanding
+  // update requests reaches zero.
+  virtual void RequestStopUpdates() = 0;
+
   // Enum defining origin of a cached file.
   enum CachedFileOrigin {
     CACHED_FILE_FROM_SERVER = 0,
     CACHED_FILE_LOCALLY_MODIFIED,
     CACHED_FILE_MOUNTED,
   };
 
   // Enum defining type of file operation e.g. copy or move, etc.
   // For now, it's used for StoreToCache.
   enum FileOperationType {
@@ skipping 205 matching lines @@
                         public content::NotificationObserver {
  public:
   GDataFileSystem(Profile* profile,
                   DocumentsServiceInterface* documents_service);
   virtual ~GDataFileSystem();
 
   // GDataFileSystem overrides.
   virtual void Initialize() OVERRIDE;
   virtual void AddObserver(Observer* observer) OVERRIDE;
   virtual void RemoveObserver(Observer* observer) OVERRIDE;
+  virtual void RequestStartUpdates() OVERRIDE;
+  virtual void RequestStopUpdates() OVERRIDE;
   virtual void Authenticate(const AuthStatusCallback& callback) OVERRIDE;
   virtual void FindEntryByResourceIdSync(const std::string& resource_id,
                                          FindEntryDelegate* delegate) OVERRIDE;
   virtual void TransferFile(const FilePath& local_file_path,
                             const FilePath& remote_dest_file_path,
                             const FileOperationCallback& callback) OVERRIDE;
   virtual void Copy(const FilePath& src_file_path,
                     const FilePath& dest_file_path,
                     const FileOperationCallback& callback) OVERRIDE;
   virtual void Move(const FilePath& src_file_path,
@@ skipping 883 matching lines @@
                                const std::string& md5,
                                const GetCacheStateCallback& callback);
   void GetAvailableSpaceOnUIThread(const GetAvailableSpaceCallback& callback);
   void SetPinStateOnUIThread(const FilePath& file_path, bool to_pin,
                              const FileOperationCallback& callback);
   void SetMountedStateOnUIThread(
       const FilePath& file_path,
       bool to_mount,
       const SetMountedStateCallback& callback);
 
+  // Checks for updates on the server.
+  void CheckForUpdates();
+
   scoped_ptr<GDataRootDirectory> root_;
 
   // This guards regular states.
   base::Lock lock_;
 
   // The profile hosts the GDataFileSystem via GDataSystemService.
   Profile* profile_;
 
   // The document service for the GDataFileSystem.
   scoped_ptr<DocumentsServiceInterface> documents_service_;
@@ skipping 10 matching lines @@
   scoped_ptr<base::WaitableEvent> on_io_completed_;
 
   // True if cache initialization has started, is in progress or has completed,
   // we only want to initialize cache once.
   bool cache_initialization_started_;
 
   // Number of pending tasks on the blocking thread pool.
   int num_pending_tasks_;
   base::Lock num_pending_tasks_lock_;
 
+  // Number of active update requests.
+  int num_update_requests_;
+
+  // Periodic timer for checking updates.
+  base::Timer update_timer_;
+
   // True if hosted documents should be hidden.
   bool hide_hosted_docs_;
 
   scoped_ptr<PrefChangeRegistrar> pref_registrar_;
 
   // WeakPtrFactory and WeakPtr bound to the UI thread.
   scoped_ptr<base::WeakPtrFactory<GDataFileSystem> > ui_weak_ptr_factory_;
   base::WeakPtr<GDataFileSystem> ui_weak_ptr_;
 
   ObserverList<Observer> observers_;
@@ skipping 18 matching lines @@
 };
 
 // Sets the free disk space getter for testing.
 // The existing getter is deleted.
 void SetFreeDiskSpaceGetterForTesting(
     FreeDiskSpaceGetterInterface* getter);
 
 }  // namespace gdata
 
 #endif  // CHROME_BROWSER_CHROMEOS_GDATA_GDATA_FILE_SYSTEM_H_