content/browser/geolocation/location_arbitrator_impl.cc

   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/location_arbitrator_impl.h"
   6
   7 #include <map>
   8
   9 #include "base/bind.h"
  10 #include "base/bind_helpers.h"
  11 #include "content/browser/geolocation/network_location_provider.h"
  12 #include "content/public/browser/access_token_store.h"
  13 #include "content/public/browser/content_browser_client.h"
  14 #include "content/public/common/content_client.h"
  15 #include "url/gurl.h"
  16
  17 namespace content {
  18 namespace {
  19
  20 const char* kDefaultNetworkProviderUrl =
  21     "https://www.googleapis.com/geolocation/v1/geolocate";
  22 }  // namespace
  23
  24 // To avoid oscillations, set this to twice the expected update interval of a
  25 // a GPS-type location provider (in case it misses a beat) plus a little.
  26 const int64 LocationArbitratorImpl::kFixStaleTimeoutMilliseconds =
  27     11 * base::Time::kMillisecondsPerSecond;
  28
  29 LocationArbitratorImpl::LocationArbitratorImpl(
  30     const LocationUpdateCallback& callback)
  31     : arbitrator_update_callback_(callback),
  32       provider_update_callback_(
  33           base::Bind(&LocationArbitratorImpl::OnLocationUpdate,
  34                      base::Unretained(this))),
  35       position_provider_(NULL),
  36       is_permission_granted_(false),
  37       is_running_(false) {
  38 }
  39
  40 LocationArbitratorImpl::~LocationArbitratorImpl() {
  41 }
  42
  43 GURL LocationArbitratorImpl::DefaultNetworkProviderURL() {
  44   return GURL(kDefaultNetworkProviderUrl);
  45 }
  46
  47 void LocationArbitratorImpl::OnPermissionGranted() {
  48   is_permission_granted_ = true;
  49   for (ScopedVector<LocationProvider>::iterator i = providers_.begin();
  50       i != providers_.end(); ++i) {
  51     (*i)->OnPermissionGranted();
  52   }
  53 }
  54
  55 void LocationArbitratorImpl::StartProviders(bool use_high_accuracy) {
  56   // GetAccessTokenStore() will return NULL for embedders not implementing
  57   // the AccessTokenStore class, so we report an error to avoid JavaScript
  58   // requests of location to wait eternally for a reply.
  59   AccessTokenStore* access_token_store = GetAccessTokenStore();
  60   if (!access_token_store) {
  61     Geoposition position;
  62     position.error_code = Geoposition::ERROR_CODE_PERMISSION_DENIED;
  63     arbitrator_update_callback_.Run(position);
  64     return;
  65   }
  66
  67   // Stash options as OnAccessTokenStoresLoaded has not yet been called.
  68   is_running_ = true;
  69   use_high_accuracy_ = use_high_accuracy;
  70   if (providers_.empty()) {
  71     DCHECK(DefaultNetworkProviderURL().is_valid());
  72     access_token_store->LoadAccessTokens(
  73         base::Bind(&LocationArbitratorImpl::OnAccessTokenStoresLoaded,
  74                    base::Unretained(this)));
  75   } else {
  76     DoStartProviders();
  77   }
  78 }
  79
  80 void LocationArbitratorImpl::DoStartProviders() {
  81   for (ScopedVector<LocationProvider>::iterator i = providers_.begin();
  82        i != providers_.end(); ++i) {
  83     (*i)->StartProvider(use_high_accuracy_);
  84   }
  85 }
  86
  87 void LocationArbitratorImpl::StopProviders() {
  88   // Reset the reference location state (provider+position)
  89   // so that future starts use fresh locations from
  90   // the newly constructed providers.
  91   position_provider_ = NULL;
  92   position_ = Geoposition();
  93
  94   providers_.clear();
  95   is_running_ = false;
  96 }
  97
  98 void LocationArbitratorImpl::OnAccessTokenStoresLoaded(
  99     AccessTokenStore::AccessTokenSet access_token_set,
 100     net::URLRequestContextGetter* context_getter) {
 101   if (!is_running_ || !providers_.empty()) {
 102     // A second StartProviders() call may have arrived before the first
 103     // completed.
 104     return;
 105   }
 106   // If there are no access tokens, boot strap it with the default server URL.
 107   if (access_token_set.empty())
 108     access_token_set[DefaultNetworkProviderURL()];
 109   for (AccessTokenStore::AccessTokenSet::iterator i =
 110            access_token_set.begin();
 111       i != access_token_set.end(); ++i) {
 112     RegisterProvider(
 113         NewNetworkLocationProvider(
 114             GetAccessTokenStore(), context_getter,
 115             i->first, i->second));
 116   }
 117
 118   LocationProvider* provider =
 119       GetContentClient()->browser()->OverrideSystemLocationProvider();
 120   if (!provider)
 121     provider = NewSystemLocationProvider();
 122   RegisterProvider(provider);
 123   DoStartProviders();
 124 }
 125
 126 void LocationArbitratorImpl::RegisterProvider(
 127     LocationProvider* provider) {
 128   if (!provider)
 129     return;
 130   provider->SetUpdateCallback(provider_update_callback_);
 131   if (is_permission_granted_)
 132     provider->OnPermissionGranted();
 133   providers_.push_back(provider);
 134 }
 135
 136 void LocationArbitratorImpl::OnLocationUpdate(const LocationProvider* provider,
 137                                               const Geoposition& new_position) {
 138   DCHECK(new_position.Validate() ||
 139          new_position.error_code != Geoposition::ERROR_CODE_NONE);
 140   if (!IsNewPositionBetter(position_, new_position,
 141                            provider == position_provider_))
 142     return;
 143   position_provider_ = provider;
 144   position_ = new_position;
 145   arbitrator_update_callback_.Run(position_);
 146 }
 147
 148 AccessTokenStore* LocationArbitratorImpl::NewAccessTokenStore() {
 149   return GetContentClient()->browser()->CreateAccessTokenStore();
 150 }
 151
 152 AccessTokenStore* LocationArbitratorImpl::GetAccessTokenStore() {
 153   if (!access_token_store_.get())
 154     access_token_store_ = NewAccessTokenStore();
 155   return access_token_store_.get();
 156 }
 157
 158 LocationProvider* LocationArbitratorImpl::NewNetworkLocationProvider(
 159     AccessTokenStore* access_token_store,
 160     net::URLRequestContextGetter* context,
 161     const GURL& url,
 162     const base::string16& access_token) {
 163 #if defined(OS_ANDROID)
 164   // Android uses its own SystemLocationProvider.
 165   return NULL;
 166 #else
 167   return new NetworkLocationProvider(access_token_store, context, url,
 168                                      access_token);
 169 #endif
 170 }
 171
 172 LocationProvider* LocationArbitratorImpl::NewSystemLocationProvider() {
 173 #if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_LINUX)
 174   return NULL;
 175 #else
 176   return content::NewSystemLocationProvider();
 177 #endif
 178 }
 179
 180 base::Time LocationArbitratorImpl::GetTimeNow() const {
 181   return base::Time::Now();
 182 }
 183
 184 bool LocationArbitratorImpl::IsNewPositionBetter(
 185     const Geoposition& old_position, const Geoposition& new_position,
 186     bool from_same_provider) const {
 187   // Updates location_info if it's better than what we currently have,
 188   // or if it's a newer update from the same provider.
 189   if (!old_position.Validate()) {
 190     // Older location wasn't locked.
 191     return true;
 192   }
 193   if (new_position.Validate()) {
 194     // New location is locked, let's check if it's any better.
 195     if (old_position.accuracy >= new_position.accuracy) {
 196       // Accuracy is better.
 197       return true;
 198     } else if (from_same_provider) {
 199       // Same provider, fresher location.
 200       return true;
 201     } else if ((GetTimeNow() - old_position.timestamp).InMilliseconds() >
 202                kFixStaleTimeoutMilliseconds) {
 203       // Existing fix is stale.
 204       return true;
 205     }
 206   }
 207   return false;
 208 }
 209
 210 bool LocationArbitratorImpl::HasPermissionBeenGranted() const {
 211   return is_permission_granted_;
 212 }
 213
 214 }  // namespace content