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// 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 DEVICE_GEOLOCATION_LOCATION_ARBITRATOR_H_
#define DEVICE_GEOLOCATION_LOCATION_ARBITRATOR_H_
#include <stdint.h>
#include <memory>
#include <vector>
#include "base/callback_forward.h"
#include "base/cancelable_callback.h"
#include "base/macros.h"
#include "base/strings/string16.h"
#include "base/time/time.h"
#include "device/geolocation/geolocation_export.h"
#include "device/geolocation/geolocation_provider_impl.h"
#include "device/geolocation/public/cpp/location_provider.h"
#include "device/geolocation/public/interfaces/geoposition.mojom.h"
#include "net/url_request/url_request_context_getter.h"
#include "url/gurl.h"
namespace net {
class URLRequestContextGetter;
}
namespace device {
// This class is responsible for handling updates from multiple underlying
// providers and resolving them to a single 'best' location fix at any given
// moment.
class DEVICE_GEOLOCATION_EXPORT LocationArbitrator : public LocationProvider {
public:
// The TimeDelta newer a location provider has to be that it's worth
// switching to this location provider on the basis of it being fresher
// (regardles of relative accuracy). Public for tests.
static const base::TimeDelta kFixStaleTimeoutTimeDelta;
// If the |custom_location_provider_getter| callback returns nullptr, then
// LocationArbitrator uses the default system location provider.
LocationArbitrator(
const CustomLocationProviderCallback& custom_location_provider_getter,
const GeolocationProvider::RequestContextProducer
request_context_producer,
const std::string& api_key);
~LocationArbitrator() override;
static GURL DefaultNetworkProviderURL();
bool HasPermissionBeenGrantedForTest() const;
// LocationProvider implementation.
void SetUpdateCallback(
const LocationProviderUpdateCallback& callback) override;
void StartProvider(bool enable_high_accuracy) override;
void StopProvider() override;
const mojom::Geoposition& GetPosition() override;
void OnPermissionGranted() override;
protected:
// These functions are useful for injection of dependencies in derived
// testing classes.
virtual std::unique_ptr<LocationProvider> NewNetworkLocationProvider(
scoped_refptr<net::URLRequestContextGetter> context,
const std::string& api_key);
virtual std::unique_ptr<LocationProvider> NewSystemLocationProvider();
virtual base::Time GetTimeNow() const;
private:
friend class TestingLocationArbitrator;
// Provider will either be added to |providers_| or
// deleted on error (e.g. it fails to start).
void RegisterProvider(std::unique_ptr<LocationProvider> provider);
void RegisterSystemProvider();
// Tells all registered providers to start.
// If |providers_| is empty, immediately provides
// Geoposition::ERROR_CODE_POSITION_UNAVAILABLE to the client via
// |arbitrator_update_callback_|.
void DoStartProviders();
// Response callback for request_context_callback_.
void OnRequestContextResponse(
scoped_refptr<net::URLRequestContextGetter> context_getter);
// Gets called when a provider has a new position.
void OnLocationUpdate(const LocationProvider* provider,
const mojom::Geoposition& new_position);
// Returns true if |new_position| is an improvement over |old_position|.
// Set |from_same_provider| to true if both the positions came from the same
// provider.
bool IsNewPositionBetter(const mojom::Geoposition& old_position,
const mojom::Geoposition& new_position,
bool from_same_provider) const;
const CustomLocationProviderCallback custom_location_provider_getter_;
const GeolocationProvider::RequestContextProducer request_context_producer_;
const std::string api_key_;
LocationProvider::LocationProviderUpdateCallback arbitrator_update_callback_;
// CancelableCallback to prevent OnRequestContextReponse from being called
// multiple times in case request_context_callback_ is invoked multiple times.
base::CancelableCallback<void(scoped_refptr<net::URLRequestContextGetter>)>
request_context_response_callback_;
std::vector<std::unique_ptr<LocationProvider>> providers_;
bool enable_high_accuracy_;
// The provider which supplied the current |position_|
const LocationProvider* position_provider_;
bool is_permission_granted_;
// The current best estimate of our position.
mojom::Geoposition position_;
// Tracks whether providers should be running.
bool is_running_;
DISALLOW_COPY_AND_ASSIGN(LocationArbitrator);
};
// Factory functions for the various types of location provider to abstract
// over the platform-dependent implementations.
std::unique_ptr<LocationProvider> NewSystemLocationProvider();
} // namespace device
#endif // DEVICE_GEOLOCATION_LOCATION_ARBITRATOR_H_