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   // Stash options as OnAccessTokenStoresLoaded has not yet been called.
  57   is_running_ = true;
  58   use_high_accuracy_ = use_high_accuracy;
  59   if (providers_.empty()) {
  60     DCHECK(DefaultNetworkProviderURL().is_valid());
  61     GetAccessTokenStore()->LoadAccessTokens(
  62         base::Bind(&LocationArbitratorImpl::OnAccessTokenStoresLoaded,
  63                    base::Unretained(this)));
  64   } else {
  65     DoStartProviders();
  66   }
  67 }
  68
  69 void LocationArbitratorImpl::DoStartProviders() {
  70   for (ScopedVector<LocationProvider>::iterator i = providers_.begin();
  71        i != providers_.end(); ++i) {
  72     (*i)->StartProvider(use_high_accuracy_);
  73   }
  74 }
  75
  76 void LocationArbitratorImpl::StopProviders() {
  77   // Reset the reference location state (provider+position)
  78   // so that future starts use fresh locations from
  79   // the newly constructed providers.
  80   position_provider_ = NULL;
  81   position_ = Geoposition();
  82
  83   providers_.clear();
  84   is_running_ = false;
  85 }
  86
  87 void LocationArbitratorImpl::OnAccessTokenStoresLoaded(
  88     AccessTokenStore::AccessTokenSet access_token_set,
  89     net::URLRequestContextGetter* context_getter) {
  90   if (!is_running_ || !providers_.empty()) {
  91     // A second StartProviders() call may have arrived before the first
  92     // completed.
  93     return;
  94   }
  95   // If there are no access tokens, boot strap it with the default server URL.
  96   if (access_token_set.empty())
  97     access_token_set[DefaultNetworkProviderURL()];
  98   for (AccessTokenStore::AccessTokenSet::iterator i =
  99            access_token_set.begin();
 100       i != access_token_set.end(); ++i) {
 101     RegisterProvider(
 102         NewNetworkLocationProvider(
 103             GetAccessTokenStore(), context_getter,
 104             i->first, i->second));
 105   }
 106
 107   LocationProvider* provider =
 108       GetContentClient()->browser()->OverrideSystemLocationProvider();
 109   if (!provider)
 110     provider = NewSystemLocationProvider();
 111   RegisterProvider(provider);
 112   DoStartProviders();
 113 }
 114
 115 void LocationArbitratorImpl::RegisterProvider(
 116     LocationProvider* provider) {
 117   if (!provider)
 118     return;
 119   provider->SetUpdateCallback(provider_update_callback_);
 120   if (is_permission_granted_)
 121     provider->OnPermissionGranted();
 122   providers_.push_back(provider);
 123 }
 124
 125 void LocationArbitratorImpl::OnLocationUpdate(const LocationProvider* provider,
 126                                               const Geoposition& new_position) {
 127   DCHECK(new_position.Validate() ||
 128          new_position.error_code != Geoposition::ERROR_CODE_NONE);
 129   if (!IsNewPositionBetter(position_, new_position,
 130                            provider == position_provider_))
 131     return;
 132   position_provider_ = provider;
 133   position_ = new_position;
 134   arbitrator_update_callback_.Run(position_);
 135 }
 136
 137 AccessTokenStore* LocationArbitratorImpl::NewAccessTokenStore() {
 138   return GetContentClient()->browser()->CreateAccessTokenStore();
 139 }
 140
 141 AccessTokenStore* LocationArbitratorImpl::GetAccessTokenStore() {
 142   if (!access_token_store_.get())
 143     access_token_store_ = NewAccessTokenStore();
 144   return access_token_store_.get();
 145 }
 146
 147 LocationProvider* LocationArbitratorImpl::NewNetworkLocationProvider(
 148     AccessTokenStore* access_token_store,
 149     net::URLRequestContextGetter* context,
 150     const GURL& url,
 151     const base::string16& access_token) {
 152 #if defined(OS_ANDROID)
 153   // Android uses its own SystemLocationProvider.
 154   return NULL;
 155 #else
 156   return new NetworkLocationProvider(access_token_store, context, url,
 157                                      access_token);
 158 #endif
 159 }
 160
 161 LocationProvider* LocationArbitratorImpl::NewSystemLocationProvider() {
 162 #if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_LINUX)
 163   return NULL;
 164 #else
 165   return content::NewSystemLocationProvider();
 166 #endif
 167 }
 168
 169 base::Time LocationArbitratorImpl::GetTimeNow() const {
 170   return base::Time::Now();
 171 }
 172
 173 bool LocationArbitratorImpl::IsNewPositionBetter(
 174     const Geoposition& old_position, const Geoposition& new_position,
 175     bool from_same_provider) const {
 176   // Updates location_info if it's better than what we currently have,
 177   // or if it's a newer update from the same provider.
 178   if (!old_position.Validate()) {
 179     // Older location wasn't locked.
 180     return true;
 181   }
 182   if (new_position.Validate()) {
 183     // New location is locked, let's check if it's any better.
 184     if (old_position.accuracy >= new_position.accuracy) {
 185       // Accuracy is better.
 186       return true;
 187     } else if (from_same_provider) {
 188       // Same provider, fresher location.
 189       return true;
 190     } else if ((GetTimeNow() - old_position.timestamp).InMilliseconds() >
 191                kFixStaleTimeoutMilliseconds) {
 192       // Existing fix is stale.
 193       return true;
 194     }
 195   }
 196   return false;
 197 }
 198
 199 bool LocationArbitratorImpl::HasPermissionBeenGranted() const {
 200   return is_permission_granted_;
 201 }
 202
 203 }  // namespace content