power_manager/powerd/system/input_watcher_interface.h

// Copyright 2014 The Chromium OS 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 POWER_MANAGER_POWERD_SYSTEM_INPUT_WATCHER_INTERFACE_H_
#define POWER_MANAGER_POWERD_SYSTEM_INPUT_WATCHER_INTERFACE_H_

#include <base/macros.h>

#include "power_manager/common/power_constants.h"

namespace power_manager {
namespace system {

class InputObserver;

// An interface for querying vaguely-input-related state.
class InputWatcherInterface {
 public:
  InputWatcherInterface() {}
  virtual ~InputWatcherInterface() {}

  // Adds or removes an observer.
  virtual void AddObserver(InputObserver* observer) = 0;
  virtual void RemoveObserver(InputObserver* observer) = 0;

  // Queries the system for the current lid state. LidState::NOT_PRESENT is
  // returned on error.
  virtual LidState QueryLidState() = 0;

  // Returns the most-recently-observed state from the tablet mode switch (if
  // any).
  virtual TabletMode GetTabletMode() = 0;

  // Checks if any USB input devices are connected.
  virtual bool IsUSBInputDeviceConnected() const = 0;

  // Should be called at the beginning of a new suspend request.
  virtual void PrepareForSuspendRequest() = 0;

  // Should be called at the end of a suspend request.
  virtual void HandleResume() = 0;

  // Returns true if any of the input devices' wakeup counts differed (compared
  // to the pre-suspend wakeup counts).
  virtual bool InputDeviceCausedLastWake() const = 0;

 private:
  DISALLOW_COPY_AND_ASSIGN(InputWatcherInterface);
};

}  // namespace system
}  // namespace power_manager

#endif  // POWER_MANAGER_POWERD_SYSTEM_INPUT_WATCHER_INTERFACE_H_