chromeos/dbus/system_clock_client.h

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROMEOS_DBUS_SYSTEM_CLOCK_CLIENT_H_
   6 #define CHROMEOS_DBUS_SYSTEM_CLOCK_CLIENT_H_
   7
   8 #include "base/observer_list.h"
   9 #include "chromeos/chromeos_export.h"
  10 #include "chromeos/dbus/dbus_client_implementation_type.h"
  11
  12 namespace dbus {
  13 class Bus;
  14 }  // namespace
  15
  16 namespace chromeos {
  17
  18 // SystemClockClient is used to communicate with the system clock.
  19 class CHROMEOS_EXPORT SystemClockClient {
  20  public:
  21   // Interface for observing changes from the system clock.
  22   class Observer {
  23    public:
  24     // Called when the status is updated.
  25     virtual void SystemClockUpdated() {}
  26    protected:
  27     virtual ~Observer() {}
  28   };
  29
  30   virtual ~SystemClockClient();
  31
  32   // Adds and removes the observer.
  33   virtual void AddObserver(Observer* observer) = 0;
  34   virtual void RemoveObserver(Observer* observer) = 0;
  35   // Returns true if this object has the given observer.
  36   virtual bool HasObserver(Observer* observer) = 0;
  37
  38   // Creates the instance.
  39   static SystemClockClient* Create(DBusClientImplementationType type,
  40                                    dbus::Bus* bus);
  41
  42  protected:
  43   // Create() should be used instead.
  44   SystemClockClient();
  45
  46  private:
  47   DISALLOW_COPY_AND_ASSIGN(SystemClockClient);
  48 };
  49
  50 }  // namespace chromeos
  51
  52 #endif  // CHROMEOS_DBUS_SYSTEM_CLOCK_CLIENT_H_