chromeos/dbus/metronome_client.h

   1 // Copyright 2015 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_METRONOME_CLIENT_H_
   6 #define CHROMEOS_DBUS_METRONOME_CLIENT_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/callback_forward.h"
  10 #include "base/memory/ref_counted.h"
  11 #include "chromeos/chromeos_export.h"
  12 #include "chromeos/dbus/dbus_client.h"
  13 #include "chromeos/dbus/dbus_client_implementation_type.h"
  14
  15 namespace chromeos {
  16
  17 // A DBus client class for the org.chromium.Metronome service.
  18 class CHROMEOS_EXPORT MetronomeClient : public DBusClient {
  19  public:
  20   // Interface for observing timestamp events from a metronome client.
  21   class Observer {
  22    public:
  23     // Called when the TimestampUpdated signal is received.
  24     virtual void OnTimestampUpdated(uint64 beacon_timestamp,
  25                                     uint64 local_timestamp) = 0;
  26     virtual ~Observer() {}
  27   };
  28
  29   ~MetronomeClient() override;
  30
  31   // Adds and removes observers for timestamp events.
  32   virtual void AddObserver(Observer* observer) = 0;
  33   virtual void RemoveObserver(Observer* observer) = 0;
  34
  35   // Factory function, creates a new instance and returns ownership.
  36   // For normal usage, access the singleton via DBusThreadManager::Get().
  37   static MetronomeClient* Create(DBusClientImplementationType type);
  38
  39  protected:
  40   // Create() should be used instead.
  41   MetronomeClient();
  42
  43  private:
  44   DISALLOW_COPY_AND_ASSIGN(MetronomeClient);
  45 };
  46
  47 }  // namespace chromeos
  48
  49 #endif  // CHROMEOS_DBUS_METRONOME_CLIENT_H_