src/chrome/browser/extensions/api/location/location_manager.cc

   1 // Copyright (c) 2013 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 "chrome/browser/extensions/api/location/location_manager.h"
   6
   7 #include <math.h>
   8 #include <vector>
   9
  10 #include "base/bind.h"
  11 #include "base/lazy_instance.h"
  12 #include "base/time/time.h"
  13 #include "chrome/common/extensions/api/location.h"
  14 #include "content/public/browser/browser_thread.h"
  15 #include "content/public/browser/geolocation_provider.h"
  16 #include "content/public/common/geoposition.h"
  17 #include "extensions/browser/event_router.h"
  18 #include "extensions/browser/extension_registry.h"
  19 #include "extensions/browser/extension_system.h"
  20 #include "extensions/common/extension.h"
  21 #include "extensions/common/permissions/permission_set.h"
  22 #include "extensions/common/permissions/permissions_data.h"
  23
  24 using content::BrowserThread;
  25
  26 // TODO(vadimt): Add tests.
  27 namespace extensions {
  28
  29 namespace location = api::location;
  30
  31 namespace updatepolicy {
  32
  33 // Base class for all update policies for sending a location.
  34 class UpdatePolicy : public base::RefCounted<UpdatePolicy> {
  35  public:
  36   explicit UpdatePolicy() {}
  37
  38   // True if the caller should send an update based off of this policy.
  39   virtual bool ShouldSendUpdate(const content::Geoposition&) const = 0;
  40
  41   // Updates any policy state on reporting a position.
  42   virtual void OnPositionReported(const content::Geoposition&) = 0;
  43
  44  protected:
  45   virtual ~UpdatePolicy() {}
  46
  47  private:
  48   friend class base::RefCounted<UpdatePolicy>;
  49   DISALLOW_COPY_AND_ASSIGN(UpdatePolicy);
  50 };
  51
  52 // A policy that controls sending an update below a distance threshold.
  53 class DistanceBasedUpdatePolicy : public UpdatePolicy {
  54  public:
  55   explicit DistanceBasedUpdatePolicy(double distance_update_threshold_meters) :
  56       distance_update_threshold_meters_(distance_update_threshold_meters)
  57   {}
  58
  59   // UpdatePolicy Implementation
  60   bool ShouldSendUpdate(const content::Geoposition& position) const override {
  61     return !last_updated_position_.Validate() ||
  62         Distance(position.latitude,
  63                  position.longitude,
  64                  last_updated_position_.latitude,
  65                  last_updated_position_.longitude) >
  66             distance_update_threshold_meters_;
  67   }
  68
  69   void OnPositionReported(const content::Geoposition& position) override {
  70     last_updated_position_ = position;
  71   }
  72
  73  private:
  74   ~DistanceBasedUpdatePolicy() override {}
  75
  76   // Calculates the distance between two latitude and longitude points.
  77   static double Distance(const double latitude1,
  78                          const double longitude1,
  79                          const double latitude2,
  80                          const double longitude2) {
  81     // The earth has a radius of about 6371 km.
  82     const double kRadius = 6371000;
  83     const double kPi = 3.14159265358979323846;
  84     const double kDegreesToRadians = kPi / 180.0;
  85
  86     // Conversions
  87     const double latitude1Rad = latitude1 * kDegreesToRadians;
  88     const double latitude2Rad = latitude2 * kDegreesToRadians;
  89     const double latitudeDistRad = latitude2Rad - latitude1Rad;
  90     const double longitudeDistRad = (longitude2 - longitude1) *
  91                                     kDegreesToRadians;
  92
  93     // The Haversine Formula determines the great circle distance
  94     // between two points on a sphere.
  95     const double chordLengthSquared = pow(sin(latitudeDistRad / 2.0), 2) +
  96                                       (pow(sin(longitudeDistRad / 2.0), 2) *
  97                                        cos(latitude1Rad) *
  98                                        cos(latitude2Rad));
  99     const double angularDistance = 2.0 * atan2(sqrt(chordLengthSquared),
 100                                                sqrt(1.0 - chordLengthSquared));
 101     return kRadius * angularDistance;
 102   }
 103
 104   const double distance_update_threshold_meters_;
 105   content::Geoposition last_updated_position_;
 106
 107   DISALLOW_COPY_AND_ASSIGN(DistanceBasedUpdatePolicy);
 108 };
 109
 110 // A policy that controls sending an update above a time threshold.
 111 class TimeBasedUpdatePolicy : public UpdatePolicy {
 112  public:
 113   explicit TimeBasedUpdatePolicy(double time_between_updates_ms) :
 114       time_between_updates_ms_(time_between_updates_ms)
 115   {}
 116
 117   // UpdatePolicy Implementation
 118   bool ShouldSendUpdate(const content::Geoposition&) const override {
 119     return (base::Time::Now() - last_update_time_).InMilliseconds() >
 120         time_between_updates_ms_;
 121   }
 122
 123   void OnPositionReported(const content::Geoposition&) override {
 124     last_update_time_ = base::Time::Now();
 125   }
 126
 127  private:
 128   ~TimeBasedUpdatePolicy() override {}
 129
 130   base::Time last_update_time_;
 131   const double time_between_updates_ms_;
 132
 133   DISALLOW_COPY_AND_ASSIGN(TimeBasedUpdatePolicy);
 134 };
 135
 136 } // namespace updatepolicy
 137
 138 // Request created by chrome.location.watchLocation() call.
 139 class LocationRequest : public base::RefCounted<LocationRequest> {
 140  public:
 141   LocationRequest(
 142       LocationManager* location_manager,
 143       const std::string& extension_id,
 144       const std::string& request_name,
 145       const double* distance_update_threshold_meters,
 146       const double* time_between_updates_ms);
 147
 148   const std::string& request_name() const { return request_name_; }
 149
 150  private:
 151   friend class base::RefCounted<LocationRequest>;
 152    ~LocationRequest();
 153
 154   void OnLocationUpdate(const content::Geoposition& position);
 155
 156   // Determines if all policies say to send a position update.
 157   // If there are no policies, this always says yes.
 158   bool ShouldSendUpdate(const content::Geoposition& position);
 159
 160   // Updates the policies on sending a position update.
 161   void OnPositionReported(const content::Geoposition& position);
 162
 163   // Request name.
 164   const std::string request_name_;
 165
 166   // Id of the owner extension.
 167   const std::string extension_id_;
 168
 169   // Owning location manager.
 170   LocationManager* location_manager_;
 171
 172   // Holds Update Policies.
 173   typedef std::vector<scoped_refptr<updatepolicy::UpdatePolicy> >
 174       UpdatePolicyVector;
 175   UpdatePolicyVector update_policies_;
 176
 177   scoped_ptr<content::GeolocationProvider::Subscription>
 178       geolocation_subscription_;
 179
 180   DISALLOW_COPY_AND_ASSIGN(LocationRequest);
 181 };
 182
 183 LocationRequest::LocationRequest(
 184     LocationManager* location_manager,
 185     const std::string& extension_id,
 186     const std::string& request_name,
 187     const double* distance_update_threshold_meters,
 188     const double* time_between_updates_ms)
 189     : request_name_(request_name),
 190       extension_id_(extension_id),
 191       location_manager_(location_manager) {
 192   // TODO(vadimt): use request_info.
 193   if (time_between_updates_ms) {
 194     update_policies_.push_back(
 195         new updatepolicy::TimeBasedUpdatePolicy(
 196             *time_between_updates_ms));
 197   }
 198
 199   if (distance_update_threshold_meters) {
 200     update_policies_.push_back(
 201         new updatepolicy::DistanceBasedUpdatePolicy(
 202               *distance_update_threshold_meters));
 203   }
 204
 205   // TODO(vadimt): This can get a location cached by GeolocationProvider,
 206   // contrary to the API definition which says that creating a location watch
 207   // will get new location.
 208   geolocation_subscription_ = content::GeolocationProvider::GetInstance()->
 209       AddLocationUpdateCallback(
 210           base::Bind(&LocationRequest::OnLocationUpdate,
 211                      base::Unretained(this)),
 212           true);
 213 }
 214
 215 LocationRequest::~LocationRequest() {
 216 }
 217
 218 void LocationRequest::OnLocationUpdate(const content::Geoposition& position) {
 219   if (ShouldSendUpdate(position)) {
 220     OnPositionReported(position);
 221     location_manager_->SendLocationUpdate(
 222         extension_id_, request_name_, position);
 223   }
 224 }
 225
 226 bool LocationRequest::ShouldSendUpdate(const content::Geoposition& position) {
 227   for (UpdatePolicyVector::iterator it = update_policies_.begin();
 228        it != update_policies_.end();
 229        ++it) {
 230     if (!((*it)->ShouldSendUpdate(position))) {
 231       return false;
 232     }
 233   }
 234   return true;
 235 }
 236
 237 void LocationRequest::OnPositionReported(const content::Geoposition& position) {
 238   for (UpdatePolicyVector::iterator it = update_policies_.begin();
 239        it != update_policies_.end();
 240        ++it) {
 241     (*it)->OnPositionReported(position);
 242   }
 243 }
 244
 245 LocationManager::LocationManager(content::BrowserContext* context)
 246     : browser_context_(context), extension_registry_observer_(this) {
 247   extension_registry_observer_.Add(ExtensionRegistry::Get(browser_context_));
 248 }
 249
 250 void LocationManager::AddLocationRequest(
 251     const std::string& extension_id,
 252     const std::string& request_name,
 253     const double* distance_update_threshold_meters,
 254     const double* time_between_updates_ms) {
 255   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 256   // TODO(vadimt): Consider resuming requests after restarting the browser.
 257
 258   // Override any old request with the same name.
 259   RemoveLocationRequest(extension_id, request_name);
 260
 261   LocationRequestPointer location_request =
 262       new LocationRequest(this,
 263                           extension_id,
 264                           request_name,
 265                           distance_update_threshold_meters,
 266                           time_between_updates_ms);
 267   location_requests_.insert(
 268       LocationRequestMap::value_type(extension_id, location_request));
 269 }
 270
 271 void LocationManager::RemoveLocationRequest(const std::string& extension_id,
 272                                             const std::string& name) {
 273   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 274
 275   std::pair<LocationRequestMap::iterator, LocationRequestMap::iterator>
 276       extension_range = location_requests_.equal_range(extension_id);
 277
 278   for (LocationRequestMap::iterator it = extension_range.first;
 279        it != extension_range.second;
 280        ++it) {
 281     if (it->second->request_name() == name) {
 282       location_requests_.erase(it);
 283       return;
 284     }
 285   }
 286 }
 287
 288 LocationManager::~LocationManager() {
 289 }
 290
 291 void LocationManager::GeopositionToApiCoordinates(
 292       const content::Geoposition& position,
 293       location::Coordinates* coordinates) {
 294   coordinates->latitude = position.latitude;
 295   coordinates->longitude = position.longitude;
 296   if (position.altitude > -10000.)
 297     coordinates->altitude.reset(new double(position.altitude));
 298   coordinates->accuracy = position.accuracy;
 299   if (position.altitude_accuracy >= 0.) {
 300     coordinates->altitude_accuracy.reset(
 301         new double(position.altitude_accuracy));
 302   }
 303   if (position.heading >= 0. && position.heading <= 360.)
 304     coordinates->heading.reset(new double(position.heading));
 305   if (position.speed >= 0.)
 306     coordinates->speed.reset(new double(position.speed));
 307 }
 308
 309 void LocationManager::SendLocationUpdate(
 310     const std::string& extension_id,
 311     const std::string& request_name,
 312     const content::Geoposition& position) {
 313   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 314
 315   scoped_ptr<base::ListValue> args(new base::ListValue());
 316   std::string event_name;
 317
 318   if (position.Validate() &&
 319       position.error_code == content::Geoposition::ERROR_CODE_NONE) {
 320     // Set data for onLocationUpdate event.
 321     location::Location location;
 322     location.name = request_name;
 323     GeopositionToApiCoordinates(position, &location.coords);
 324     location.timestamp = position.timestamp.ToJsTime();
 325
 326     args->Append(location.ToValue().release());
 327     event_name = location::OnLocationUpdate::kEventName;
 328   } else {
 329     // Set data for onLocationError event.
 330     // TODO(vadimt): Set name.
 331     args->AppendString(position.error_message);
 332     event_name = location::OnLocationError::kEventName;
 333   }
 334
 335   scoped_ptr<Event> event(new Event(event_name, args.Pass()));
 336
 337   EventRouter::Get(browser_context_)
 338       ->DispatchEventToExtension(extension_id, event.Pass());
 339 }
 340
 341 void LocationManager::OnExtensionLoaded(
 342     content::BrowserContext* browser_context,
 343     const Extension* extension) {
 344   // Grants permission to use geolocation once an extension with "location"
 345   // permission is loaded.
 346   if (extension->permissions_data()->HasAPIPermission(
 347           APIPermission::kLocation)) {
 348     content::GeolocationProvider::GetInstance()
 349         ->UserDidOptIntoLocationServices();
 350   }
 351 }
 352
 353 void LocationManager::OnExtensionUnloaded(
 354     content::BrowserContext* browser_context,
 355     const Extension* extension,
 356     UnloadedExtensionInfo::Reason reason) {
 357   // Delete all requests from the unloaded extension.
 358   location_requests_.erase(extension->id());
 359 }
 360
 361 static base::LazyInstance<BrowserContextKeyedAPIFactory<LocationManager> >
 362     g_factory = LAZY_INSTANCE_INITIALIZER;
 363
 364 // static
 365 BrowserContextKeyedAPIFactory<LocationManager>*
 366 LocationManager::GetFactoryInstance() {
 367   return g_factory.Pointer();
 368 }
 369
 370 // static
 371 LocationManager* LocationManager::Get(content::BrowserContext* context) {
 372   return BrowserContextKeyedAPIFactory<LocationManager>::Get(context);
 373 }
 374
 375 }  // namespace extensions