base/power_monitor/power_monitor.h

   1 // Copyright 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 BASE_POWER_MONITOR_POWER_MONITOR_H_
   6 #define BASE_POWER_MONITOR_POWER_MONITOR_H_
   7
   8 #include "base/base_export.h"
   9 #include "base/basictypes.h"
  10 #include "base/memory/ref_counted.h"
  11 #include "base/observer_list_threadsafe.h"
  12 #include "base/power_monitor/power_observer.h"
  13
  14 namespace base {
  15
  16 class PowerMonitorSource;
  17
  18 // A class used to monitor the power state change and notify the observers about
  19 // the change event.
  20 class BASE_EXPORT PowerMonitor {
  21  public:
  22   // Takes ownership of |source|.
  23   explicit PowerMonitor(scoped_ptr<PowerMonitorSource> source);
  24   ~PowerMonitor();
  25
  26   // Get the process-wide PowerMonitor (if not present, returns NULL).
  27   static PowerMonitor* Get();
  28
  29   // Add and remove an observer.
  30   // Can be called from any thread.
  31   // Must not be called from within a notification callback.
  32   void AddObserver(PowerObserver* observer);
  33   void RemoveObserver(PowerObserver* observer);
  34
  35   // Is the computer currently on battery power.
  36   bool IsOnBatteryPower();
  37
  38  private:
  39   friend class PowerMonitorSource;
  40
  41   PowerMonitorSource* Source();
  42
  43   void NotifyPowerStateChange(bool battery_in_use);
  44   void NotifySuspend();
  45   void NotifyResume();
  46
  47   scoped_refptr<ObserverListThreadSafe<PowerObserver> > observers_;
  48   scoped_ptr<PowerMonitorSource> source_;
  49
  50   DISALLOW_COPY_AND_ASSIGN(PowerMonitor);
  51 };
  52
  53 }  // namespace base
  54
  55 #endif  // BASE_POWER_MONITOR_POWER_MONITOR_H_