content/public/browser/power_save_blocker.h

// Copyright (c) 2012 The Chromium 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 CONTENT_PUBLIC_BROWSER_POWER_SAVE_BLOCKER_H_
#define CONTENT_PUBLIC_BROWSER_POWER_SAVE_BLOCKER_H_

#include <string>

#include "base/basictypes.h"
#include "base/memory/scoped_ptr.h"
#include "content/common/content_export.h"

namespace content {

// A RAII-style class to block the system from entering low-power (sleep) mode.
// This class is thread-safe; it may be constructed and deleted on any thread.
class CONTENT_EXPORT PowerSaveBlocker {
 public:
  enum PowerSaveBlockerType {
    // Prevent the application from being suspended. On some platforms, apps may
    // be suspended when they are not visible to the user. This type of block
    // requests that the app continue to run in that case, and on all platforms
    // prevents the system from sleeping.
    // Example use cases: downloading a file, playing audio.
    kPowerSaveBlockPreventAppSuspension,

    // Prevent the display from going to sleep. This also has the side effect of
    // preventing the system from sleeping, but does not necessarily prevent the
    // app from being suspended on some platforms if the user hides it.
    // Example use case: playing video.
    kPowerSaveBlockPreventDisplaySleep,
  };

  virtual ~PowerSaveBlocker() = 0;

  // Pass in the type of power save blocking desired. If multiple types of
  // blocking are desired, instantiate one PowerSaveBlocker for each type.
  // |reason| may be provided to the underlying system APIs on some platforms.
  static scoped_ptr<PowerSaveBlocker> Create(PowerSaveBlockerType type,
                                             const std::string& reason);
};

}  // namespace content

#endif  // CONTENT_PUBLIC_BROWSER_POWER_SAVE_BLOCKER_H_