Hooks together Geolocation Feature in the Client and Engine.

device/geolocation/location_arbitrator_impl.cc

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "device/geolocation/location_arbitrator_impl.h"
-
-#include <map>
-#include <memory>
-#include <utility>
-
-#include "base/bind.h"
-#include "base/bind_helpers.h"
-#include "base/memory/ptr_util.h"
-#include "build/build_config.h"
-#include "device/geolocation/access_token_store.h"
-#include "device/geolocation/geolocation_delegate.h"
-#include "device/geolocation/network_location_provider.h"
-#include "url/gurl.h"
-
-namespace device {
-namespace {
-
-const char* kDefaultNetworkProviderUrl =
-    "https://www.googleapis.com/geolocation/v1/geolocate";
-}  // namespace
-
-// To avoid oscillations, set this to twice the expected update interval of a
-// a GPS-type location provider (in case it misses a beat) plus a little.
-const int64_t LocationArbitratorImpl::kFixStaleTimeoutMilliseconds =
-    11 * base::Time::kMillisecondsPerSecond;
-
-LocationArbitratorImpl::LocationArbitratorImpl(
-    GeolocationDelegate* delegate)
-    : delegate_(delegate),
-      position_provider_(nullptr),
-      is_permission_granted_(false),
-      is_running_(false) {}
-
-LocationArbitratorImpl::~LocationArbitratorImpl() {}
-
-GURL LocationArbitratorImpl::DefaultNetworkProviderURL() {
-  return GURL(kDefaultNetworkProviderUrl);
-}
-
-bool LocationArbitratorImpl::HasPermissionBeenGrantedForTest() const {
-  return is_permission_granted_;
-}
-
-void LocationArbitratorImpl::OnPermissionGranted() {
-  is_permission_granted_ = true;
-  for (const auto& provider : providers_)
-    provider->OnPermissionGranted();
-}
-
-bool LocationArbitratorImpl::StartProvider(bool enable_high_accuracy) {
-  // Stash options as OnAccessTokenStoresLoaded has not yet been called.
-  is_running_ = true;
-  enable_high_accuracy_ = enable_high_accuracy;
-
-  if (providers_.empty()) {
-    RegisterSystemProvider();
-
-    const scoped_refptr<AccessTokenStore> access_token_store =
-        GetAccessTokenStore();
-    if (access_token_store && delegate_->UseNetworkLocationProviders()) {
-      DCHECK(DefaultNetworkProviderURL().is_valid());
-      token_store_callback_.Reset(
-          base::Bind(&LocationArbitratorImpl::OnAccessTokenStoresLoaded,
-                     base::Unretained(this)));
-      access_token_store->LoadAccessTokens(token_store_callback_.callback());
-      return true;
-    }
-  }
-  return DoStartProviders();
-}
-
-bool LocationArbitratorImpl::DoStartProviders() {
-  if (providers_.empty()) {
-    // If no providers are available, we report an error to avoid
-    // callers waiting indefinitely for a reply.
-    Geoposition position;
-    position.error_code = Geoposition::ERROR_CODE_PERMISSION_DENIED;
-    arbitrator_update_callback_.Run(this, position);
-    return false;
-  }
-  bool started = false;
-  for (const auto& provider : providers_) {
-    started = provider->StartProvider(enable_high_accuracy_) || started;
-  }
-  return started;
-}
-
-void LocationArbitratorImpl::StopProvider() {
-  // Reset the reference location state (provider+position)
-  // so that future starts use fresh locations from
-  // the newly constructed providers.
-  position_provider_ = nullptr;
-  position_ = Geoposition();
-
-  providers_.clear();
-  is_running_ = false;
-}
-
-void LocationArbitratorImpl::OnAccessTokenStoresLoaded(
-    AccessTokenStore::AccessTokenMap access_token_map,
-    const scoped_refptr<net::URLRequestContextGetter>& context_getter) {
-  // If there are no access tokens, boot strap it with the default server URL.
-  if (access_token_map.empty())
-    access_token_map[DefaultNetworkProviderURL()];
-  for (const auto& entry : access_token_map) {
-    RegisterProvider(NewNetworkLocationProvider(
-        GetAccessTokenStore(), context_getter, entry.first, entry.second));
-  }
-  DoStartProviders();
-}
-
-void LocationArbitratorImpl::RegisterProvider(
-    std::unique_ptr<LocationProvider> provider) {
-  if (!provider)
-    return;
-  provider->SetUpdateCallback(base::Bind(
-      &LocationArbitratorImpl::OnLocationUpdate, base::Unretained(this)));
-  if (is_permission_granted_)
-    provider->OnPermissionGranted();
-  providers_.push_back(std::move(provider));
-}
-
-void LocationArbitratorImpl::RegisterSystemProvider() {
-  std::unique_ptr<LocationProvider> provider =
-      delegate_->OverrideSystemLocationProvider();
-  if (!provider)
-    provider = NewSystemLocationProvider();
-  RegisterProvider(std::move(provider));
-}
-
-void LocationArbitratorImpl::OnLocationUpdate(const LocationProvider* provider,
-                                              const Geoposition& new_position) {
-  DCHECK(new_position.Validate() ||
-         new_position.error_code != Geoposition::ERROR_CODE_NONE);
-  if (!IsNewPositionBetter(position_, new_position,
-                           provider == position_provider_))
-    return;
-  position_provider_ = provider;
-  position_ = new_position;
-  arbitrator_update_callback_.Run(this, position_);
-}
-
-const Geoposition& LocationArbitratorImpl::GetPosition() {
-  return position_;
-}
-
-void LocationArbitratorImpl::SetUpdateCallback(
-    const LocationProviderUpdateCallback& callback) {
-  DCHECK(!callback.is_null());
-  arbitrator_update_callback_ = callback;
-}
-
-scoped_refptr<AccessTokenStore> LocationArbitratorImpl::NewAccessTokenStore() {
-  return delegate_->CreateAccessTokenStore();
-}
-
-scoped_refptr<AccessTokenStore> LocationArbitratorImpl::GetAccessTokenStore() {
-  if (!access_token_store_)
-    access_token_store_ = NewAccessTokenStore();
-  return access_token_store_;
-}
-
-std::unique_ptr<LocationProvider>
-LocationArbitratorImpl::NewNetworkLocationProvider(
-    const scoped_refptr<AccessTokenStore>& access_token_store,
-    const scoped_refptr<net::URLRequestContextGetter>& context,
-    const GURL& url,
-    const base::string16& access_token) {
-#if defined(OS_ANDROID)
-  // Android uses its own SystemLocationProvider.
-  return nullptr;
-#else
-  return base::MakeUnique<NetworkLocationProvider>(access_token_store, context,
-                                                   url, access_token);
-#endif
-}
-
-std::unique_ptr<LocationProvider>
-LocationArbitratorImpl::NewSystemLocationProvider() {
-#if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_LINUX)
-  return nullptr;
-#else
-  return device::NewSystemLocationProvider();
-#endif
-}
-
-base::Time LocationArbitratorImpl::GetTimeNow() const {
-  return base::Time::Now();
-}
-
-bool LocationArbitratorImpl::IsNewPositionBetter(
-    const Geoposition& old_position,
-    const Geoposition& new_position,
-    bool from_same_provider) const {
-  // Updates location_info if it's better than what we currently have,
-  // or if it's a newer update from the same provider.
-  if (!old_position.Validate()) {
-    // Older location wasn't locked.
-    return true;
-  }
-  if (new_position.Validate()) {
-    // New location is locked, let's check if it's any better.
-    if (old_position.accuracy >= new_position.accuracy) {
-      // Accuracy is better.
-      return true;
-    } else if (from_same_provider) {
-      // Same provider, fresher location.
-      return true;
-    } else if ((GetTimeNow() - old_position.timestamp).InMilliseconds() >
-               kFixStaleTimeoutMilliseconds) {
-      // Existing fix is stale.
-      return true;
-    }
-  }
-  return false;
-}
-
-}  // namespace device