content/browser/geolocation/location_arbitrator_impl.h

   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/port/browser/location_provider.h"
  15 #include "content/public/browser/access_token_store.h"
  16 #include "content/public/common/geoposition.h"
  17 #include "net/url_request/url_request_context_getter.h"
  18
  19 namespace net {
  20 class URLRequestContextGetter;
  21 }
  22
  23 namespace content {
  24 class AccessTokenStore;
  25 class 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.
  30 class 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   // The providers call this function when a new position is available.
  74   void LocationUpdateAvailable(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 callback_;
  86   LocationProvider::LocationProviderUpdateCallback provider_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.
 103 LocationProvider* NewSystemLocationProvider();
 104
 105 }  // namespace content
 106
 107 #endif  // CONTENT_BROWSER_GEOLOCATION_LOCATION_ARBITRATOR_IMPL_H_