text: // 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.
  
  #ifndef CONTENT_BROWSER_GEOLOCATION_GEOLOCATION_PROVIDER_IMPL_H_
  #define CONTENT_BROWSER_GEOLOCATION_GEOLOCATION_PROVIDER_IMPL_H_
  
  #include <list>
  #include <memory>
  #include <vector>
  
  #include "base/callback_forward.h"
  #include "base/compiler_specific.h"
  #include "base/macros.h"
  #include "base/threading/thread.h"
  #include "content/common/content_export.h"
  #include "content/public/browser/geolocation_provider.h"
  #include "content/public/common/geoposition.h"
  
  namespace base {
  template<typename Type> struct DefaultSingletonTraits;
  }
  
  namespace content {
  class LocationArbitrator;
  
  class CONTENT_EXPORT GeolocationProviderImpl
      : public NON_EXPORTED_BASE(GeolocationProvider),
        public base::Thread {
   public:
    // GeolocationProvider implementation:
    std::unique_ptr<GeolocationProvider::Subscription> AddLocationUpdateCallback(
        const LocationUpdateCallback& callback,
        bool enable_high_accuracy) override;
    void UserDidOptIntoLocationServices() override;
    void OverrideLocationForTesting(const Geoposition& position) override;
  
    // Callback from the LocationArbitrator. Public for testing.
    void OnLocationUpdate(const Geoposition& position);
  
    // Gets a pointer to the singleton instance of the location relayer, which
    // is in turn bound to the browser's global context objects. This must only be
    // called on the UI thread so that the GeolocationProviderImpl is always
    // instantiated on the same thread. Ownership is NOT returned.
    static GeolocationProviderImpl* GetInstance();
  
    bool user_did_opt_into_location_services_for_testing() {
      return user_did_opt_into_location_services_;
    }
  
   protected:
    friend struct base::DefaultSingletonTraits<GeolocationProviderImpl>;
    GeolocationProviderImpl();
    ~GeolocationProviderImpl() override;
  
    // Useful for injecting mock geolocation arbitrator in tests.
    // TODO(mvanouwerkerk): Use something like SetArbitratorForTesting instead.
    virtual std::unique_ptr<LocationArbitrator> CreateArbitrator();
  
   private:
    bool OnGeolocationThread() const;
  
    // Start and stop providers as needed when clients are added or removed.
    void OnClientsChanged();
  
    // Stops the providers when there are no more registered clients. Note that
    // once the Geolocation thread is started, it will stay alive (but sitting
    // idle without any pending messages).
    void StopProviders();
  
    // Starts the geolocation providers or updates their options (delegates to
    // arbitrator).
    void StartProviders(bool enable_high_accuracy);
  
    // Updates the providers on the geolocation thread, which must be running.
    void InformProvidersPermissionGranted();
  
    // Notifies all registered clients that a position update is available.
    void NotifyClients(const Geoposition& position);
  
    // Thread
    void Init() override;
    void CleanUp() override;
  
    base::CallbackList<void(const Geoposition&)> high_accuracy_callbacks_;
    base::CallbackList<void(const Geoposition&)> low_accuracy_callbacks_;
  
    bool user_did_opt_into_location_services_;
    Geoposition position_;
  
    // True only in testing, where we want to use a custom position.
    bool ignore_location_updates_;
  
    // Only to be used on the geolocation thread.
    std::unique_ptr<LocationArbitrator> arbitrator_;
  
    DISALLOW_COPY_AND_ASSIGN(GeolocationProviderImpl);
  };
  
  }  // namespace content
  
  #endif  // CONTENT_BROWSER_GEOLOCATION_GEOLOCATION_PROVIDER_IMPL_H_
  