1 // Copyright (c) 2011 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_TIMER_HI_RES_TIMER_MANAGER_H_
6 #define BASE_TIMER_HI_RES_TIMER_MANAGER_H_
7 
8 #include "base/base_export.h"
9 #include "base/macros.h"
10 #include "base/memory/ref_counted.h"
11 #include "base/power_monitor/power_observer.h"
12 #include "base/timer/timer.h"
13 #include "build/build_config.h"
14 
15 namespace base {
16 
17 // Ensures that the Windows high resolution timer is only used
18 // when not running on battery power.
19 class BASE_EXPORT HighResolutionTimerManager : public base::PowerObserver {
20  public:
21   HighResolutionTimerManager();
22   ~HighResolutionTimerManager() override;
23 
24   // base::PowerObserver methods.
25   void OnPowerStateChange(bool on_battery_power) override;
26   void OnSuspend() override;
27   void OnResume() override;
28 
29   // Returns true if the hi resolution clock could be used right now.
hi_res_clock_available()30   bool hi_res_clock_available() const { return hi_res_clock_available_; }
31 
32  private:
33   // Enable or disable the faster multimedia timer.
34   void UseHiResClock(bool use);
35 
36   bool hi_res_clock_available_;
37 
38 #if defined(OS_WIN)
39   // Timer for polling the high resolution timer usage.
40   base::RepeatingTimer timer_;
41 #endif
42 
43   DISALLOW_COPY_AND_ASSIGN(HighResolutionTimerManager);
44 };
45 
46 }  // namespace base
47 
48 #endif  // BASE_TIMER_HI_RES_TIMER_MANAGER_H_
49