Index: base/system_monitor.h |
=================================================================== |
--- base/system_monitor.h (revision 4449) |
+++ base/system_monitor.h (working copy) |
@@ -5,13 +5,12 @@ |
#ifndef BASE_SYSTEM_MONITOR_H_ |
#define BASE_SYSTEM_MONITOR_H_ |
-#include "base/logging.h" |
-#include "base/observer_list.h" |
+#include "base/observer_list_threadsafe.h" |
#include "base/singleton.h" |
namespace base { |
-// Singleton class for monitoring various system-related subsystems |
+// Class for monitoring various system-related subsystems |
// such as power management, network status, etc. |
// TODO(mbelshe): Add support beyond just power management. |
class SystemMonitor { |
@@ -21,25 +20,33 @@ |
return Singleton<SystemMonitor>::get(); |
} |
+ // To start the System Monitor within an application |
+ // use this call. |
+ static void Start(); |
+ |
// |
// Power-related APIs |
// |
// Is the computer currently on battery power. |
- bool BatteryPower() { return battery_in_use_; } |
+ // Can be called on any thread. |
+ bool BatteryPower() { |
+ // Using a lock here is not necessary for just a bool. |
+ 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 |
+ POWER_STATE_EVENT, // The Power status of the system has changed. |
+ SUSPEND_EVENT, // The system is being suspended. |
+ RESUME_EVENT // The system is being resumed. |
}; |
+ // Callbacks will be called on the thread which creates the SystemMonitor. |
+ // During the callback, Add/RemoveObserver will block until the callbacks |
+ // are finished. Observers should implement quick callback functions; if |
+ // lengthy operations are needed, the observer should take care to invoke |
+ // the operation on an appropriate thread. |
class PowerObserver { |
public: |
// Notification of a change in power status of the computer, such |
@@ -53,33 +60,16 @@ |
virtual void OnResume(SystemMonitor*) = 0; |
}; |
- void AddObserver(PowerObserver* obs) { |
- observer_list_.AddObserver(obs); |
- } |
+ // Add a new observer. |
+ // Can be called from any thread. |
+ // Must not be called from within a notification callback. |
+ void AddObserver(PowerObserver* obs); |
- void RemoveObserver(PowerObserver* obs) { |
- observer_list_.RemoveObserver(obs); |
- } |
+ // Remove an existing observer. |
+ // Can be called from any thread. |
+ // Must not be called from within a notification callback. |
+ void RemoveObserver(PowerObserver* 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 |
@@ -88,19 +78,33 @@ |
#endif |
// Cross-platform handling of a power event. |
- // This is only exposed for testing. |
void ProcessPowerMessage(PowerEvent event_id); |
+ // Constructor. |
+ // Don't use this; access SystemMonitor via the Singleton. |
+ SystemMonitor(); |
+ |
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_; |
+ // Checks the battery status and notifies observers if the battery |
+ // status has changed. |
+ void BatteryCheck(); |
+ |
+ // Functions to trigger notifications. |
+ void NotifyPowerStateChange(); |
+ void NotifySuspend(); |
+ void NotifyResume(); |
+ |
+ scoped_refptr<ObserverListThreadSafe<PowerObserver> > observer_list_; |
bool battery_in_use_; |
bool suspended_; |
+ base::OneShotTimer<SystemMonitor> delayed_battery_check_; |
+ |
DISALLOW_COPY_AND_ASSIGN(SystemMonitor); |
}; |