power_save_blocker.h revision 2a99a7e74a7f215066514fe81d2bfa6639d9eddd 
1// Copyright (c) 2012 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 CONTENT_PUBLIC_BROWSER_POWER_SAVE_BLOCKER_H_
6#define CONTENT_PUBLIC_BROWSER_POWER_SAVE_BLOCKER_H_
7
8#include <string>
9
10#include "base/basictypes.h"
11#include "base/memory/scoped_ptr.h"
12#include "content/common/content_export.h"
13
14namespace content {
15
16// A RAII-style class to block the system from entering low-power (sleep) mode.
17// This class is thread-safe; it may be constructed and deleted on any thread.
18class CONTENT_EXPORT PowerSaveBlocker {
19 public:
20  enum PowerSaveBlockerType {
21    // Prevent the application from being suspended. On some platforms, apps may
22    // be suspended when they are not visible to the user. This type of block
23    // requests that the app continue to run in that case, and on all platforms
24    // prevents the system from sleeping.
25    // Example use cases: downloading a file, playing audio.
26    kPowerSaveBlockPreventAppSuspension,
27
28    // Prevent the display from going to sleep. This also has the side effect of
29    // preventing the system from sleeping, but does not necessarily prevent the
30    // app from being suspended on some platforms if the user hides it.
31    // Example use case: playing video.
32    kPowerSaveBlockPreventDisplaySleep,
33  };
34
35  virtual ~PowerSaveBlocker() = 0;
36
37  // Pass in the type of power save blocking desired. If multiple types of
38  // blocking are desired, instantiate one PowerSaveBlocker for each type.
39  // |reason| may be provided to the underlying system APIs on some platforms.
40  static scoped_ptr<PowerSaveBlocker> Create(PowerSaveBlockerType type,
41                                             const std::string& reason);
42};
43
44}  // namespace content
45
46#endif  // CONTENT_PUBLIC_BROWSER_POWER_SAVE_BLOCKER_H_
47