device/battery/battery_status_manager_linux.cc

   1 // Copyright 2014 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 "device/battery/battery_status_manager_linux.h"
   6
   7 #include "base/macros.h"
   8 #include "base/metrics/histogram.h"
   9 #include "base/threading/thread.h"
  10 #include "base/values.h"
  11 #include "dbus/bus.h"
  12 #include "dbus/message.h"
  13 #include "dbus/object_path.h"
  14 #include "dbus/object_proxy.h"
  15 #include "dbus/property.h"
  16 #include "dbus/values_util.h"
  17 #include "device/battery/battery_status_manager.h"
  18
  19 namespace device {
  20
  21 namespace {
  22
  23 const char kUPowerServiceName[] = "org.freedesktop.UPower";
  24 const char kUPowerDeviceName[] = "org.freedesktop.UPower.Device";
  25 const char kUPowerPath[] = "/org/freedesktop/UPower";
  26 const char kUPowerDeviceSignalChanged[] = "Changed";
  27 const char kUPowerEnumerateDevices[] = "EnumerateDevices";
  28 const char kBatteryNotifierThreadName[] = "BatteryStatusNotifier";
  29
  30 // UPowerDeviceType reflects the possible UPower.Device.Type values,
  31 // see upower.freedesktop.org/docs/Device.html#Device:Type.
  32 enum UPowerDeviceType {
  33   UPOWER_DEVICE_TYPE_UNKNOWN = 0,
  34   UPOWER_DEVICE_TYPE_LINE_POWER = 1,
  35   UPOWER_DEVICE_TYPE_BATTERY = 2,
  36   UPOWER_DEVICE_TYPE_UPS = 3,
  37   UPOWER_DEVICE_TYPE_MONITOR = 4,
  38   UPOWER_DEVICE_TYPE_MOUSE = 5,
  39   UPOWER_DEVICE_TYPE_KEYBOARD = 6,
  40   UPOWER_DEVICE_TYPE_PDA = 7,
  41   UPOWER_DEVICE_TYPE_PHONE = 8,
  42 };
  43
  44 typedef std::vector<dbus::ObjectPath> PathsVector;
  45
  46 double GetPropertyAsDouble(const base::DictionaryValue& dictionary,
  47                            const std::string& property_name,
  48                            double default_value) {
  49   double value = default_value;
  50   return dictionary.GetDouble(property_name, &value) ? value : default_value;
  51 }
  52
  53 bool GetPropertyAsBoolean(const base::DictionaryValue& dictionary,
  54                           const std::string& property_name,
  55                           bool default_value) {
  56   bool value = default_value;
  57   return dictionary.GetBoolean(property_name, &value) ? value : default_value;
  58 }
  59
  60 scoped_ptr<base::DictionaryValue> GetPropertiesAsDictionary(
  61     dbus::ObjectProxy* proxy) {
  62   dbus::MethodCall method_call(dbus::kPropertiesInterface,
  63                                dbus::kPropertiesGetAll);
  64   dbus::MessageWriter builder(&method_call);
  65   builder.AppendString(kUPowerDeviceName);
  66
  67   scoped_ptr<dbus::Response> response(
  68       proxy->CallMethodAndBlock(&method_call,
  69                                 dbus::ObjectProxy::TIMEOUT_USE_DEFAULT));
  70   if (response) {
  71     dbus::MessageReader reader(response.get());
  72     scoped_ptr<base::Value> value(dbus::PopDataAsValue(&reader));
  73     base::DictionaryValue* dictionary_value = NULL;
  74     if (value && value->GetAsDictionary(&dictionary_value)) {
  75       ignore_result(value.release());
  76       return scoped_ptr<base::DictionaryValue>(dictionary_value);
  77     }
  78   }
  79   return scoped_ptr<base::DictionaryValue>();
  80 }
  81
  82 scoped_ptr<PathsVector> GetPowerSourcesPaths(dbus::ObjectProxy* proxy) {
  83   scoped_ptr<PathsVector> paths(new PathsVector());
  84   if (!proxy)
  85     return paths.Pass();
  86
  87   dbus::MethodCall method_call(kUPowerServiceName, kUPowerEnumerateDevices);
  88   scoped_ptr<dbus::Response> response(
  89       proxy->CallMethodAndBlock(&method_call,
  90                                 dbus::ObjectProxy::TIMEOUT_USE_DEFAULT));
  91
  92   if (response) {
  93     dbus::MessageReader reader(response.get());
  94     reader.PopArrayOfObjectPaths(paths.get());
  95   }
  96   return paths.Pass();;
  97 }
  98
  99 void UpdateNumberBatteriesHistogram(int count) {
 100   UMA_HISTOGRAM_CUSTOM_COUNTS(
 101       "BatteryStatus.NumberBatteriesLinux", count, 1, 5, 6);
 102 }
 103
 104 // Class that represents a dedicated thread which communicates with DBus to
 105 // obtain battery information and receives battery change notifications.
 106 class BatteryStatusNotificationThread : public base::Thread {
 107  public:
 108   BatteryStatusNotificationThread(
 109       const BatteryStatusService::BatteryUpdateCallback& callback)
 110       : base::Thread(kBatteryNotifierThreadName),
 111         callback_(callback),
 112         battery_proxy_(NULL) {}
 113
 114   ~BatteryStatusNotificationThread() override {
 115     // Make sure to shutdown the dbus connection if it is still open in the very
 116     // end. It needs to happen on the BatteryStatusNotificationThread.
 117     message_loop()->PostTask(
 118         FROM_HERE,
 119         base::Bind(&BatteryStatusNotificationThread::ShutdownDBusConnection,
 120                    base::Unretained(this)));
 121
 122     // Drain the message queue of the BatteryStatusNotificationThread and stop.
 123     Stop();
 124   }
 125
 126   void StartListening() {
 127     DCHECK(OnWatcherThread());
 128
 129     if (system_bus_.get())
 130       return;
 131
 132     InitDBus();
 133     dbus::ObjectProxy* power_proxy =
 134         system_bus_->GetObjectProxy(kUPowerServiceName,
 135                                     dbus::ObjectPath(kUPowerPath));
 136     scoped_ptr<PathsVector> device_paths = GetPowerSourcesPaths(power_proxy);
 137     int num_batteries = 0;
 138
 139     for (size_t i = 0; i < device_paths->size(); ++i) {
 140       const dbus::ObjectPath& device_path = device_paths->at(i);
 141       dbus::ObjectProxy* device_proxy = system_bus_->GetObjectProxy(
 142           kUPowerServiceName, device_path);
 143       scoped_ptr<base::DictionaryValue> dictionary =
 144           GetPropertiesAsDictionary(device_proxy);
 145
 146       if (!dictionary)
 147         continue;
 148
 149       bool is_present = GetPropertyAsBoolean(*dictionary, "IsPresent", false);
 150       uint32 type = static_cast<uint32>(
 151           GetPropertyAsDouble(*dictionary, "Type", UPOWER_DEVICE_TYPE_UNKNOWN));
 152
 153       if (!is_present || type != UPOWER_DEVICE_TYPE_BATTERY) {
 154         system_bus_->RemoveObjectProxy(kUPowerServiceName,
 155                                        device_path,
 156                                        base::Bind(&base::DoNothing));
 157         continue;
 158       }
 159
 160       if (battery_proxy_) {
 161         // TODO(timvolodine): add support for multiple batteries. Currently we
 162         // only collect information from the first battery we encounter
 163         // (crbug.com/400780).
 164         LOG(WARNING) << "multiple batteries found, "
 165                      << "using status data of the first battery only.";
 166       } else {
 167         battery_proxy_ = device_proxy;
 168       }
 169       num_batteries++;
 170     }
 171
 172     UpdateNumberBatteriesHistogram(num_batteries);
 173
 174     if (!battery_proxy_) {
 175       callback_.Run(BatteryStatus());
 176       return;
 177     }
 178
 179     battery_proxy_->ConnectToSignal(
 180         kUPowerDeviceName,
 181         kUPowerDeviceSignalChanged,
 182         base::Bind(&BatteryStatusNotificationThread::BatteryChanged,
 183                    base::Unretained(this)),
 184         base::Bind(&BatteryStatusNotificationThread::OnSignalConnected,
 185                    base::Unretained(this)));
 186   }
 187
 188   void StopListening() {
 189     DCHECK(OnWatcherThread());
 190     ShutdownDBusConnection();
 191   }
 192
 193  private:
 194   bool OnWatcherThread() {
 195     return task_runner()->BelongsToCurrentThread();
 196   }
 197
 198   void InitDBus() {
 199     DCHECK(OnWatcherThread());
 200
 201     dbus::Bus::Options options;
 202     options.bus_type = dbus::Bus::SYSTEM;
 203     options.connection_type = dbus::Bus::PRIVATE;
 204     system_bus_ = new dbus::Bus(options);
 205   }
 206
 207   void ShutdownDBusConnection() {
 208     DCHECK(OnWatcherThread());
 209
 210     if (!system_bus_.get())
 211       return;
 212
 213     // Shutdown DBus connection later because there may be pending tasks on
 214     // this thread.
 215     message_loop()->PostTask(FROM_HERE,
 216                              base::Bind(&dbus::Bus::ShutdownAndBlock,
 217                                         system_bus_));
 218     system_bus_ = NULL;
 219     battery_proxy_ = NULL;
 220   }
 221
 222   void OnSignalConnected(const std::string& interface_name,
 223                          const std::string& signal_name,
 224                          bool success) {
 225     DCHECK(OnWatcherThread());
 226
 227     if (interface_name != kUPowerDeviceName ||
 228         signal_name != kUPowerDeviceSignalChanged) {
 229       return;
 230     }
 231
 232     if (!system_bus_.get())
 233       return;
 234
 235     if (success) {
 236       BatteryChanged(NULL);
 237     } else {
 238       // Failed to register for "Changed" signal, execute callback with the
 239       // default values.
 240       callback_.Run(BatteryStatus());
 241     }
 242   }
 243
 244   void BatteryChanged(dbus::Signal* signal /* unsused */) {
 245     DCHECK(OnWatcherThread());
 246
 247     if (!system_bus_.get())
 248       return;
 249
 250     scoped_ptr<base::DictionaryValue> dictionary =
 251         GetPropertiesAsDictionary(battery_proxy_);
 252     if (dictionary)
 253       callback_.Run(ComputeWebBatteryStatus(*dictionary));
 254     else
 255       callback_.Run(BatteryStatus());
 256   }
 257
 258   BatteryStatusService::BatteryUpdateCallback callback_;
 259   scoped_refptr<dbus::Bus> system_bus_;
 260   dbus::ObjectProxy* battery_proxy_;  // owned by the bus
 261
 262   DISALLOW_COPY_AND_ASSIGN(BatteryStatusNotificationThread);
 263 };
 264
 265 // Creates a notification thread and delegates Start/Stop calls to it.
 266 class BatteryStatusManagerLinux : public BatteryStatusManager {
 267  public:
 268   explicit BatteryStatusManagerLinux(
 269       const BatteryStatusService::BatteryUpdateCallback& callback)
 270       : callback_(callback) {}
 271
 272   ~BatteryStatusManagerLinux() override {}
 273
 274  private:
 275   // BatteryStatusManager:
 276   bool StartListeningBatteryChange() override {
 277     if (!StartNotifierThreadIfNecessary())
 278       return false;
 279
 280     notifier_thread_->message_loop()->PostTask(
 281         FROM_HERE,
 282         base::Bind(&BatteryStatusNotificationThread::StartListening,
 283                    base::Unretained(notifier_thread_.get())));
 284     return true;
 285   }
 286
 287   void StopListeningBatteryChange() override {
 288     if (!notifier_thread_)
 289       return;
 290
 291     notifier_thread_->message_loop()->PostTask(
 292         FROM_HERE,
 293         base::Bind(&BatteryStatusNotificationThread::StopListening,
 294                    base::Unretained(notifier_thread_.get())));
 295   }
 296
 297   // Starts the notifier thread if not already started and returns true on
 298   // success.
 299   bool StartNotifierThreadIfNecessary() {
 300     if (notifier_thread_)
 301       return true;
 302
 303     base::Thread::Options thread_options(base::MessageLoop::TYPE_IO, 0);
 304     notifier_thread_.reset(new BatteryStatusNotificationThread(callback_));
 305     if (!notifier_thread_->StartWithOptions(thread_options)) {
 306       notifier_thread_.reset();
 307       LOG(ERROR) << "Could not start the " << kBatteryNotifierThreadName
 308                  << " thread";
 309       return false;
 310     }
 311     return true;
 312   }
 313
 314   BatteryStatusService::BatteryUpdateCallback callback_;
 315   scoped_ptr<BatteryStatusNotificationThread> notifier_thread_;
 316
 317   DISALLOW_COPY_AND_ASSIGN(BatteryStatusManagerLinux);
 318 };
 319
 320 }  // namespace
 321
 322 BatteryStatus ComputeWebBatteryStatus(const base::DictionaryValue& dictionary) {
 323   BatteryStatus status;
 324   if (!dictionary.HasKey("State"))
 325     return status;
 326
 327   uint32 state = static_cast<uint32>(
 328       GetPropertyAsDouble(dictionary, "State", UPOWER_DEVICE_STATE_UNKNOWN));
 329   status.charging = state != UPOWER_DEVICE_STATE_DISCHARGING &&
 330                     state != UPOWER_DEVICE_STATE_EMPTY;
 331   double percentage = GetPropertyAsDouble(dictionary, "Percentage", 100);
 332   // Convert percentage to a value between 0 and 1 with 2 digits of precision.
 333   // This is to bring it in line with other platforms like Mac and Android where
 334   // we report level with 1% granularity. It also serves the purpose of reducing
 335   // the possibility of fingerprinting and triggers less level change events on
 336   // the blink side.
 337   // TODO(timvolodine): consider moving this rounding to the blink side.
 338   status.level = round(percentage) / 100.f;
 339
 340   switch (state) {
 341     case UPOWER_DEVICE_STATE_CHARGING : {
 342       double time_to_full = GetPropertyAsDouble(dictionary, "TimeToFull", 0);
 343       status.charging_time =
 344           (time_to_full > 0) ? time_to_full
 345                              : std::numeric_limits<double>::infinity();
 346       break;
 347     }
 348     case UPOWER_DEVICE_STATE_DISCHARGING : {
 349       double time_to_empty = GetPropertyAsDouble(dictionary, "TimeToEmpty", 0);
 350       // Set dischargingTime if it's available. Otherwise leave the default
 351       // value which is +infinity.
 352       if (time_to_empty > 0)
 353         status.discharging_time = time_to_empty;
 354       status.charging_time = std::numeric_limits<double>::infinity();
 355       break;
 356     }
 357     case UPOWER_DEVICE_STATE_FULL : {
 358       break;
 359     }
 360     default: {
 361       status.charging_time = std::numeric_limits<double>::infinity();
 362     }
 363   }
 364   return status;
 365 }
 366
 367 // static
 368 scoped_ptr<BatteryStatusManager> BatteryStatusManager::Create(
 369     const BatteryStatusService::BatteryUpdateCallback& callback) {
 370   return scoped_ptr<BatteryStatusManager>(
 371       new BatteryStatusManagerLinux(callback));
 372 }
 373
 374 }  // namespace device