1 // Copyright (c) 2012 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 "content/browser/geolocation/network_location_provider.h" 6 7 #include "base/bind.h" 8 #include "base/strings/utf_string_conversions.h" 9 #include "base/time/time.h" 10 #include "content/public/browser/access_token_store.h" 11 12 namespace content { 13 namespace { 14 // The maximum period of time we'll wait for a complete set of wifi data 15 // before sending the request. 16 const int kDataCompleteWaitSeconds = 2; 17 } // namespace 18 19 // static 20 const size_t NetworkLocationProvider::PositionCache::kMaximumSize = 10; 21 22 NetworkLocationProvider::PositionCache::PositionCache() {} 23 24 NetworkLocationProvider::PositionCache::~PositionCache() {} 25 26 bool NetworkLocationProvider::PositionCache::CachePosition( 27 const WifiData& wifi_data, 28 const Geoposition& position) { 29 // Check that we can generate a valid key for the wifi data. 30 base::string16 key; 31 if (!MakeKey(wifi_data, &key)) { 32 return false; 33 } 34 // If the cache is full, remove the oldest entry. 35 if (cache_.size() == kMaximumSize) { 36 DCHECK(cache_age_list_.size() == kMaximumSize); 37 CacheAgeList::iterator oldest_entry = cache_age_list_.begin(); 38 DCHECK(oldest_entry != cache_age_list_.end()); 39 cache_.erase(*oldest_entry); 40 cache_age_list_.erase(oldest_entry); 41 } 42 DCHECK_LT(cache_.size(), kMaximumSize); 43 // Insert the position into the cache. 44 std::pair<CacheMap::iterator, bool> result = 45 cache_.insert(std::make_pair(key, position)); 46 if (!result.second) { 47 NOTREACHED(); // We never try to add the same key twice. 48 CHECK_EQ(cache_.size(), cache_age_list_.size()); 49 return false; 50 } 51 cache_age_list_.push_back(result.first); 52 DCHECK_EQ(cache_.size(), cache_age_list_.size()); 53 return true; 54 } 55 56 // Searches for a cached position response for the current WiFi data. Returns 57 // the cached position if available, NULL otherwise. 58 const Geoposition* NetworkLocationProvider::PositionCache::FindPosition( 59 const WifiData& wifi_data) { 60 base::string16 key; 61 if (!MakeKey(wifi_data, &key)) { 62 return NULL; 63 } 64 CacheMap::const_iterator iter = cache_.find(key); 65 return iter == cache_.end() ? NULL : &iter->second; 66 } 67 68 // Makes the key for the map of cached positions, using the available data. 69 // Returns true if a good key was generated, false otherwise. 70 // 71 // static 72 bool NetworkLocationProvider::PositionCache::MakeKey( 73 const WifiData& wifi_data, 74 base::string16* key) { 75 // Currently we use only WiFi data and base the key only on the MAC addresses. 76 DCHECK(key); 77 key->clear(); 78 const size_t kCharsPerMacAddress = 6 * 3 + 1; // e.g. "11:22:33:44:55:66|" 79 key->reserve(wifi_data.access_point_data.size() * kCharsPerMacAddress); 80 const base::string16 separator(base::ASCIIToUTF16("|")); 81 for (WifiData::AccessPointDataSet::const_iterator iter = 82 wifi_data.access_point_data.begin(); 83 iter != wifi_data.access_point_data.end(); 84 iter++) { 85 *key += separator; 86 *key += iter->mac_address; 87 *key += separator; 88 } 89 // If the key is the empty string, return false, as we don't want to cache a 90 // position for such data. 91 return !key->empty(); 92 } 93 94 // NetworkLocationProvider factory function 95 LocationProviderBase* NewNetworkLocationProvider( 96 AccessTokenStore* access_token_store, 97 net::URLRequestContextGetter* context, 98 const GURL& url, 99 const base::string16& access_token) { 100 return new NetworkLocationProvider( 101 access_token_store, context, url, access_token); 102 } 103 104 // NetworkLocationProvider 105 NetworkLocationProvider::NetworkLocationProvider( 106 AccessTokenStore* access_token_store, 107 net::URLRequestContextGetter* url_context_getter, 108 const GURL& url, 109 const base::string16& access_token) 110 : access_token_store_(access_token_store), 111 wifi_data_provider_(NULL), 112 wifi_data_update_callback_( 113 base::Bind(&NetworkLocationProvider::WifiDataUpdateAvailable, 114 base::Unretained(this))), 115 is_wifi_data_complete_(false), 116 access_token_(access_token), 117 is_permission_granted_(false), 118 is_new_data_available_(false), 119 weak_factory_(this) { 120 // Create the position cache. 121 position_cache_.reset(new PositionCache()); 122 123 NetworkLocationRequest::LocationResponseCallback callback = 124 base::Bind(&NetworkLocationProvider::LocationResponseAvailable, 125 base::Unretained(this)); 126 request_.reset(new NetworkLocationRequest(url_context_getter, url, callback)); 127 } 128 129 NetworkLocationProvider::~NetworkLocationProvider() { 130 StopProvider(); 131 } 132 133 // LocationProvider implementation 134 void NetworkLocationProvider::GetPosition(Geoposition* position) { 135 DCHECK(position); 136 *position = position_; 137 } 138 139 void NetworkLocationProvider::RequestRefresh() { 140 // TODO(joth): When called via the public (base class) interface, this should 141 // poke each data provider to get them to expedite their next scan. 142 // Whilst in the delayed start, only send request if all data is ready. 143 if (!weak_factory_.HasWeakPtrs() || is_wifi_data_complete_) { 144 RequestPosition(); 145 } 146 } 147 148 void NetworkLocationProvider::OnPermissionGranted() { 149 const bool was_permission_granted = is_permission_granted_; 150 is_permission_granted_ = true; 151 if (!was_permission_granted && IsStarted()) { 152 RequestRefresh(); 153 } 154 } 155 156 void NetworkLocationProvider::WifiDataUpdateAvailable( 157 WifiDataProvider* provider) { 158 DCHECK(provider == wifi_data_provider_); 159 is_wifi_data_complete_ = wifi_data_provider_->GetData(&wifi_data_); 160 OnWifiDataUpdated(); 161 } 162 163 void NetworkLocationProvider::LocationResponseAvailable( 164 const Geoposition& position, 165 bool server_error, 166 const base::string16& access_token, 167 const WifiData& wifi_data) { 168 DCHECK(CalledOnValidThread()); 169 // Record the position and update our cache. 170 position_ = position; 171 if (position.Validate()) { 172 position_cache_->CachePosition(wifi_data, position); 173 } 174 175 // Record access_token if it's set. 176 if (!access_token.empty() && access_token_ != access_token) { 177 access_token_ = access_token; 178 access_token_store_->SaveAccessToken(request_->url(), access_token); 179 } 180 181 // Let listeners know that we now have a position available. 182 NotifyCallback(position_); 183 } 184 185 bool NetworkLocationProvider::StartProvider(bool high_accuracy) { 186 DCHECK(CalledOnValidThread()); 187 if (IsStarted()) 188 return true; 189 DCHECK(wifi_data_provider_ == NULL); 190 if (!request_->url().is_valid()) { 191 LOG(WARNING) << "StartProvider() : Failed, Bad URL: " 192 << request_->url().possibly_invalid_spec(); 193 return false; 194 } 195 196 // Registers a callback with the data provider. The first call to Register 197 // will create a singleton data provider and it will be deleted when the last 198 // callback is removed with Unregister. 199 wifi_data_provider_ = WifiDataProvider::Register(&wifi_data_update_callback_); 200 201 base::MessageLoop::current()->PostDelayedTask( 202 FROM_HERE, 203 base::Bind(&NetworkLocationProvider::RequestPosition, 204 weak_factory_.GetWeakPtr()), 205 base::TimeDelta::FromSeconds(kDataCompleteWaitSeconds)); 206 // Get the wifi data. 207 is_wifi_data_complete_ = wifi_data_provider_->GetData(&wifi_data_); 208 if (is_wifi_data_complete_) 209 OnWifiDataUpdated(); 210 return true; 211 } 212 213 void NetworkLocationProvider::OnWifiDataUpdated() { 214 DCHECK(CalledOnValidThread()); 215 wifi_data_updated_timestamp_ = base::Time::Now(); 216 217 is_new_data_available_ = is_wifi_data_complete_; 218 RequestRefresh(); 219 } 220 221 void NetworkLocationProvider::StopProvider() { 222 DCHECK(CalledOnValidThread()); 223 if (IsStarted()) { 224 wifi_data_provider_->Unregister(&wifi_data_update_callback_); 225 } 226 wifi_data_provider_ = NULL; 227 weak_factory_.InvalidateWeakPtrs(); 228 } 229 230 // Other methods 231 void NetworkLocationProvider::RequestPosition() { 232 DCHECK(CalledOnValidThread()); 233 if (!is_new_data_available_) 234 return; 235 236 const Geoposition* cached_position = 237 position_cache_->FindPosition(wifi_data_); 238 DCHECK(!wifi_data_updated_timestamp_.is_null()) << 239 "Timestamp must be set before looking up position"; 240 if (cached_position) { 241 DCHECK(cached_position->Validate()); 242 // Record the position and update its timestamp. 243 position_ = *cached_position; 244 // The timestamp of a position fix is determined by the timestamp 245 // of the source data update. (The value of position_.timestamp from 246 // the cache could be from weeks ago!) 247 position_.timestamp = wifi_data_updated_timestamp_; 248 is_new_data_available_ = false; 249 // Let listeners know that we now have a position available. 250 NotifyCallback(position_); 251 return; 252 } 253 // Don't send network requests until authorized. http://crbug.com/39171 254 if (!is_permission_granted_) 255 return; 256 257 weak_factory_.InvalidateWeakPtrs(); 258 is_new_data_available_ = false; 259 260 // TODO(joth): Rather than cancel pending requests, we should create a new 261 // NetworkLocationRequest for each and hold a set of pending requests. 262 if (request_->is_request_pending()) { 263 DVLOG(1) << "NetworkLocationProvider - pre-empting pending network request " 264 "with new data. Wifi APs: " 265 << wifi_data_.access_point_data.size(); 266 } 267 request_->MakeRequest(access_token_, wifi_data_, 268 wifi_data_updated_timestamp_); 269 } 270 271 bool NetworkLocationProvider::IsStarted() const { 272 return wifi_data_provider_ != NULL; 273 } 274 275 } // namespace content 276
