dom/battery/BatteryManager.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include <limits>
   7 #include "mozilla/Hal.h"
   8 #include "BatteryManager.h"
   9 #include "nsIDOMClassInfo.h"
  10 #include "Constants.h"
  11 #include "nsDOMEvent.h"
  12 #include "mozilla/Preferences.h"
  13 #include "nsDOMEventTargetHelper.h"
  14 #include "mozilla/dom/BatteryManagerBinding.h"
  15
  16 /**
  17  * We have to use macros here because our leak analysis tool things we are
  18  * leaking strings when we have |static const nsString|. Sad :(
  19  */
  20 #define LEVELCHANGE_EVENT_NAME           NS_LITERAL_STRING("levelchange")
  21 #define CHARGINGCHANGE_EVENT_NAME        NS_LITERAL_STRING("chargingchange")
  22 #define DISCHARGINGTIMECHANGE_EVENT_NAME NS_LITERAL_STRING("dischargingtimechange")
  23 #define CHARGINGTIMECHANGE_EVENT_NAME    NS_LITERAL_STRING("chargingtimechange")
  24
  25 namespace mozilla {
  26 namespace dom {
  27 namespace battery {
  28
  29 BatteryManager::BatteryManager()
  30   : mLevel(kDefaultLevel)
  31   , mCharging(kDefaultCharging)
  32   , mRemainingTime(kDefaultRemainingTime)
  33 {
  34   SetIsDOMBinding();
  35 }
  36
  37 void
  38 BatteryManager::Init(nsPIDOMWindow *aWindow)
  39 {
  40   BindToOwner(aWindow);
  41
  42   hal::RegisterBatteryObserver(this);
  43
  44   hal::BatteryInformation batteryInfo;
  45   hal::GetCurrentBatteryInformation(&batteryInfo);
  46
  47   UpdateFromBatteryInfo(batteryInfo);
  48 }
  49
  50 void
  51 BatteryManager::Shutdown()
  52 {
  53   hal::UnregisterBatteryObserver(this);
  54 }
  55
  56 JSObject*
  57 BatteryManager::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aScope)
  58 {
  59   return BatteryManagerBinding::Wrap(aCx, aScope, this);
  60 }
  61
  62 double
  63 BatteryManager::DischargingTime() const
  64 {
  65   if (mCharging || mRemainingTime == kUnknownRemainingTime) {
  66     return std::numeric_limits<double>::infinity();
  67   }
  68
  69   return mRemainingTime;
  70 }
  71
  72 double
  73 BatteryManager::ChargingTime() const
  74 {
  75   if (!mCharging || mRemainingTime == kUnknownRemainingTime) {
  76     return std::numeric_limits<double>::infinity();
  77   }
  78
  79   return mRemainingTime;
  80 }
  81
  82 void
  83 BatteryManager::UpdateFromBatteryInfo(const hal::BatteryInformation& aBatteryInfo)
  84 {
  85   mLevel = aBatteryInfo.level();
  86   mCharging = aBatteryInfo.charging();
  87   mRemainingTime = aBatteryInfo.remainingTime();
  88
  89   // Add some guards to make sure the values are coherent.
  90   if (mLevel == 1.0 && mCharging == true &&
  91       mRemainingTime != kDefaultRemainingTime) {
  92     mRemainingTime = kDefaultRemainingTime;
  93     NS_ERROR("Battery API: When charging and level at 1.0, remaining time "
  94              "should be 0. Please fix your backend!");
  95   }
  96 }
  97
  98 void
  99 BatteryManager::Notify(const hal::BatteryInformation& aBatteryInfo)
 100 {
 101   double previousLevel = mLevel;
 102   bool previousCharging = mCharging;
 103   double previousRemainingTime = mRemainingTime;
 104
 105   UpdateFromBatteryInfo(aBatteryInfo);
 106
 107   if (previousCharging != mCharging) {
 108     DispatchTrustedEvent(CHARGINGCHANGE_EVENT_NAME);
 109   }
 110
 111   if (previousLevel != mLevel) {
 112     DispatchTrustedEvent(LEVELCHANGE_EVENT_NAME);
 113   }
 114
 115   /*
 116    * There are a few situations that could happen here:
 117    * 1. Charging state changed:
 118    *   a. Previous remaining time wasn't unkwonw, we have to fire an event for
 119    *      the change.
 120    *   b. New remaining time isn't unkwonw, we have to fire an event for it.
 121    * 2. Charging state didn't change but remainingTime did, we have to fire
 122    *    the event that correspond to the current charging state.
 123    */
 124   if (mCharging != previousCharging) {
 125     if (previousRemainingTime != kUnknownRemainingTime) {
 126       DispatchTrustedEvent(previousCharging ? CHARGINGTIMECHANGE_EVENT_NAME
 127                                             : DISCHARGINGTIMECHANGE_EVENT_NAME);
 128     }
 129     if (mRemainingTime != kUnknownRemainingTime) {
 130       DispatchTrustedEvent(mCharging ? CHARGINGTIMECHANGE_EVENT_NAME
 131                                      : DISCHARGINGTIMECHANGE_EVENT_NAME);
 132     }
 133   } else if (previousRemainingTime != mRemainingTime) {
 134     DispatchTrustedEvent(mCharging ? CHARGINGTIMECHANGE_EVENT_NAME
 135                                    : DISCHARGINGTIMECHANGE_EVENT_NAME);
 136   }
 137 }
 138
 139 /* static */ bool
 140 BatteryManager::HasSupport()
 141 {
 142   return Preferences::GetBool("dom.battery.enabled", true);
 143 }
 144
 145 } // namespace battery
 146 } // namespace dom
 147 } // namespace mozilla