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#ifndef CONTENT_BROWSER_GEOLOCATION_LOCATION_ARBITRATOR_IMPL_H_
6#define CONTENT_BROWSER_GEOLOCATION_LOCATION_ARBITRATOR_IMPL_H_
7
8#include "base/callback_forward.h"
9#include "base/memory/scoped_vector.h"
10#include "base/strings/string16.h"
11#include "base/time/time.h"
12#include "content/browser/geolocation/location_arbitrator.h"
13#include "content/common/content_export.h"
14#include "content/public/browser/access_token_store.h"
15#include "content/public/browser/location_provider.h"
16#include "content/public/common/geoposition.h"
17#include "net/url_request/url_request_context_getter.h"
18
19namespace net {
20class URLRequestContextGetter;
21}
22
23namespace content {
24class AccessTokenStore;
25class LocationProvider;
26
27// This class is responsible for handling updates from multiple underlying
28// providers and resolving them to a single 'best' location fix at any given
29// moment.
30class CONTENT_EXPORT LocationArbitratorImpl : public LocationArbitrator {
31 public:
32  // Number of milliseconds newer a location provider has to be that it's worth
33  // switching to this location provider on the basis of it being fresher
34  // (regardles of relative accuracy). Public for tests.
35  static const int64 kFixStaleTimeoutMilliseconds;
36
37  typedef base::Callback<void(const Geoposition&)> LocationUpdateCallback;
38
39  explicit LocationArbitratorImpl(const LocationUpdateCallback& callback);
40  virtual ~LocationArbitratorImpl();
41
42  static GURL DefaultNetworkProviderURL();
43
44  // LocationArbitrator
45  virtual void StartProviders(bool use_high_accuracy) OVERRIDE;
46  virtual void StopProviders() OVERRIDE;
47  virtual void OnPermissionGranted() OVERRIDE;
48  virtual bool HasPermissionBeenGranted() const OVERRIDE;
49
50 protected:
51  AccessTokenStore* GetAccessTokenStore();
52
53  // These functions are useful for injection of dependencies in derived
54  // testing classes.
55  virtual AccessTokenStore* NewAccessTokenStore();
56  virtual LocationProvider* NewNetworkLocationProvider(
57      AccessTokenStore* access_token_store,
58      net::URLRequestContextGetter* context,
59      const GURL& url,
60      const base::string16& access_token);
61  virtual LocationProvider* NewSystemLocationProvider();
62  virtual base::Time GetTimeNow() const;
63
64 private:
65  // Takes ownership of |provider| on entry; it will either be added to
66  // |providers_| or deleted on error (e.g. it fails to start).
67  void RegisterProvider(LocationProvider* provider);
68  void OnAccessTokenStoresLoaded(
69      AccessTokenStore::AccessTokenSet access_token_store,
70      net::URLRequestContextGetter* context_getter);
71  void DoStartProviders();
72
73  // Gets called when a provider has a new position.
74  void OnLocationUpdate(const LocationProvider* provider,
75                        const Geoposition& new_position);
76
77  // Returns true if |new_position| is an improvement over |old_position|.
78  // Set |from_same_provider| to true if both the positions came from the same
79  // provider.
80  bool IsNewPositionBetter(const Geoposition& old_position,
81                           const Geoposition& new_position,
82                           bool from_same_provider) const;
83
84  scoped_refptr<AccessTokenStore> access_token_store_;
85  LocationUpdateCallback arbitrator_update_callback_;
86  LocationProvider::LocationProviderUpdateCallback provider_update_callback_;
87  ScopedVector<LocationProvider> providers_;
88  bool use_high_accuracy_;
89  // The provider which supplied the current |position_|
90  const LocationProvider* position_provider_;
91  bool is_permission_granted_;
92  // The current best estimate of our position.
93  Geoposition position_;
94
95  // Tracks whether providers should be running.
96  bool is_running_;
97
98  DISALLOW_COPY_AND_ASSIGN(LocationArbitratorImpl);
99};
100
101// Factory functions for the various types of location provider to abstract
102// over the platform-dependent implementations.
103LocationProvider* NewSystemLocationProvider();
104
105}  // namespace content
106
107#endif  // CONTENT_BROWSER_GEOLOCATION_LOCATION_ARBITRATOR_IMPL_H_
108