app/system_monitor.cc

   1 // Copyright (c) 2009 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 #include "app/system_monitor.h"
   6
   7 #include "base/logging.h"
   8 #include "base/message_loop.h"
   9 #include "base/time.h"
  10
  11 static SystemMonitor* g_system_monitor = NULL;
  12
  13 #if defined(ENABLE_BATTERY_MONITORING)
  14 // The amount of time (in ms) to wait before running the initial
  15 // battery check.
  16 static int kDelayedBatteryCheckMs = 10 * 1000;
  17 #endif  // defined(ENABLE_BATTERY_MONITORING)
  18
  19 SystemMonitor::SystemMonitor()
  20     : observer_list_(new ObserverListThreadSafe<PowerObserver>()),
  21       battery_in_use_(false),
  22       suspended_(false) {
  23   DCHECK(!g_system_monitor);
  24   g_system_monitor = this;
  25
  26   DCHECK(MessageLoop::current());
  27 #if defined(ENABLE_BATTERY_MONITORING)
  28   delayed_battery_check_.Start(
  29       base::TimeDelta::FromMilliseconds(kDelayedBatteryCheckMs), this,
  30       &SystemMonitor::BatteryCheck);
  31 #endif  // defined(ENABLE_BATTERY_MONITORING)
  32 }
  33
  34 SystemMonitor::~SystemMonitor() {
  35   DCHECK_EQ(this, g_system_monitor);
  36   g_system_monitor = NULL;
  37 }
  38
  39 // static
  40 SystemMonitor* SystemMonitor::Get() {
  41   return g_system_monitor;
  42 }
  43
  44 void SystemMonitor::ProcessPowerMessage(PowerEvent event_id) {
  45   // Suppress duplicate notifications.  Some platforms may
  46   // send multiple notifications of the same event.
  47   switch (event_id) {
  48     case POWER_STATE_EVENT:
  49       {
  50         bool on_battery = IsBatteryPower();
  51         if (on_battery != battery_in_use_) {
  52           battery_in_use_ = on_battery;
  53           NotifyPowerStateChange();
  54         }
  55       }
  56       break;
  57     case RESUME_EVENT:
  58       if (suspended_) {
  59         suspended_ = false;
  60         NotifyResume();
  61       }
  62       break;
  63     case SUSPEND_EVENT:
  64       if (!suspended_) {
  65         suspended_ = true;
  66         NotifySuspend();
  67       }
  68       break;
  69   }
  70 }
  71
  72 void SystemMonitor::AddObserver(PowerObserver* obs) {
  73   observer_list_->AddObserver(obs);
  74 }
  75
  76 void SystemMonitor::RemoveObserver(PowerObserver* obs) {
  77   observer_list_->RemoveObserver(obs);
  78 }
  79
  80 void SystemMonitor::NotifyPowerStateChange() {
  81   LOG(INFO) << L"PowerStateChange: "
  82            << (BatteryPower() ? L"On" : L"Off") << L" battery";
  83   observer_list_->Notify(&PowerObserver::OnPowerStateChange, BatteryPower());
  84 }
  85
  86 void SystemMonitor::NotifySuspend() {
  87   LOG(INFO) << L"Power Suspending";
  88   observer_list_->Notify(&PowerObserver::OnSuspend);
  89 }
  90
  91 void SystemMonitor::NotifyResume() {
  92   LOG(INFO) << L"Power Resuming";
  93   observer_list_->Notify(&PowerObserver::OnResume);
  94 }
  95
  96 void SystemMonitor::BatteryCheck() {
  97   ProcessPowerMessage(SystemMonitor::POWER_STATE_EVENT);
  98 }