The Tor Browser: ipc/chromium/src/base/system_monitor.h@6474c204b198 (annotated)

ipc/chromium/src/base/system_monitor.h@6474c204b198 (annotated)

ipc/chromium/src/base/system_monitor.h

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 // 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/observer_list_threadsafe.h"
 #include "base/singleton.h"
 // Windows HiRes timers drain the battery faster so we need to know the battery
 // status.  This isn't true for other platforms.
 #if defined(OS_WIN)
 #define ENABLE_BATTERY_MONITORING 1
 #else
 #undef ENABLE_BATTERY_MONITORING
 #endif  // !OS_WIN
 namespace base {
 // 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() {
     // Uses the LeakySingletonTrait because cleanup is optional.
     return
         Singleton<SystemMonitor, LeakySingletonTraits<SystemMonitor> >::get();
   }
   // Start the System Monitor within a process.  This method
   // is provided so that the battery check can be deferred.
   // The MessageLoop must be started before calling this
   // method.
   // This is a no-op on platforms for which ENABLE_BATTERY_MONITORING is
   // disabled.
   static void Start();
   //
   // Power-related APIs
   //
   // Is the computer currently on battery power.
   // 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 {
     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
     // 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;
   };
   // Add a new observer.
   // Can be called from any thread.
   // Must not be called from within a notification callback.
   void AddObserver(PowerObserver* obs);
   // Remove an existing observer.
   // Can be called from any thread.
   // Must not be called from within a notification callback.
   void RemoveObserver(PowerObserver* obs);
 #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.
   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();
   // 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_;
 #if defined(ENABLE_BATTERY_MONITORING)
   base::OneShotTimer<SystemMonitor> delayed_battery_check_;
 #endif
   DISALLOW_COPY_AND_ASSIGN(SystemMonitor);
 };
 }
 #endif  // BASE_SYSTEM_MONITOR_H_

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ipc/chromium/src/base/system_monitor.h@6474c204b198 (annotated)

ipc/chromium/src/base/system_monitor.h