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// Copyright (c) 2008 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 BASE_SYSTEM_MONITOR_H_
#define BASE_SYSTEM_MONITOR_H_
#include "base/logging.h"
#include "base/observer_list.h"
#include "base/singleton.h"
namespace base {
// Singleton class for monitoring various system-related subsystems
// such as power management, network status, etc.
// TODO(mbelshe): Add support beyond just power management.
class SystemMonitor {
public:
// Access to the Singleton
static SystemMonitor* Get() {
return Singleton<SystemMonitor>::get();
}
//
// Power-related APIs
//
// Is the computer currently on battery power.
bool BatteryPower() { return battery_in_use_; }
// Normalized list of power events.
enum PowerEvent {
// The Power status of the system has changed.
PowerStateEvent,
// The system is being suspended.
SuspendEvent,
// The system is being resumed.
ResumeEvent
};
class PowerObserver {
public:
// Notification of a change in power status of the computer, such
// as from switching between battery and A/C power.
virtual void OnPowerStateChange(SystemMonitor*) = 0;
// Notification that the system is suspending.
virtual void OnSuspend(SystemMonitor*) = 0;
// Notification that the system is resuming.
virtual void OnResume(SystemMonitor*) = 0;
};
void AddObserver(PowerObserver* obs) {
observer_list_.AddObserver(obs);
}
void RemoveObserver(PowerObserver* obs) {
observer_list_.RemoveObserver(obs);
}
void NotifyPowerStateChange() {
LOG(INFO) << L"PowerStateChange: "
<< (BatteryPower() ? L"On" : L"Off") << L" battery";
FOR_EACH_OBSERVER(PowerObserver, observer_list_,
OnPowerStateChange(this));
}
void NotifySuspend() {
FOR_EACH_OBSERVER(PowerObserver, observer_list_, OnSuspend(this));
}
void NotifyResume() {
FOR_EACH_OBSERVER(PowerObserver, observer_list_, OnResume(this));
}
// Constructor.
// Don't use this; access SystemMonitor via the Singleton.
SystemMonitor();
#if defined(OS_WIN)
// Windows-specific handling of a WM_POWERBROADCAST message.
// Embedders of this API should hook their top-level window
// message loop and forward WM_POWERBROADCAST through this call.
void ProcessWmPowerBroadcastMessage(int event_id);
#endif
// Cross-platform handling of a power event.
// This is only exposed for testing.
void ProcessPowerMessage(PowerEvent event_id);
private:
// Platform-specific method to check whether the system is currently
// running on battery power. Returns true if running on batteries,
// false otherwise.
bool IsBatteryPower();
ObserverList<PowerObserver> observer_list_;
bool battery_in_use_;
bool suspended_;
DISALLOW_COPY_AND_ASSIGN(SystemMonitor);
};
}
#endif // BASE_SYSTEM_MONITOR_H_
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