ash/session_state_observer.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 ASH_SESSION_STATE_OBSERVER_H_
   6 #define ASH_SESSION_STATE_OBSERVER_H_
   7
   8 #include <string>
   9
  10 #include "ash/ash_export.h"
  11 #include "ash/session_state_delegate.h"
  12 #include "base/basictypes.h"
  13
  14 namespace ash {
  15
  16 class ASH_EXPORT SessionStateObserver {
  17  public:
  18   // Called when active user has changed.
  19   virtual void ActiveUserChanged(const std::string& user_id) {}
  20
  21   // Called when another user gets added to the existing session.
  22   virtual void UserAddedToSession(const std::string& user_id) {}
  23
  24   // Called when session state is changed.
  25   virtual void SessionStateChanged(SessionStateDelegate::SessionState state) {}
  26
  27  protected:
  28   virtual ~SessionStateObserver() {}
  29 };
  30
  31 // A class to attach / detach an object as a session state observer with a
  32 // scoped pointer.
  33 class ASH_EXPORT ScopedSessionStateObserver {
  34  public:
  35   explicit ScopedSessionStateObserver(ash::SessionStateObserver* observer);
  36   virtual ~ScopedSessionStateObserver();
  37
  38  private:
  39   ash::SessionStateObserver* observer_;
  40
  41   DISALLOW_COPY_AND_ASSIGN(ScopedSessionStateObserver);
  42 };
  43
  44 }  // namespace ash
  45
  46 #endif  // ASH_SESSION_STATE_OBSERVER_H_