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/memory/scoped_vector.h"
   9 #include "base/string16.h"
  10 #include "base/time.h"
  11 #include "content/browser/geolocation/geolocation_observer.h"
  12 #include "content/browser/geolocation/location_arbitrator.h"
  13 #include "content/browser/geolocation/location_provider.h"
  14 #include "content/common/content_export.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 LocationProviderBase;
  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 GeolocationArbitratorImpl
  31     : public GeolocationArbitrator,
  32       public LocationProviderBase::ListenerInterface {
  33  public:
  34   // Number of milliseconds newer a location provider has to be that it's worth
  35   // switching to this location provider on the basis of it being fresher
  36   // (regardles of relative accuracy). Public for tests.
  37   static const int64 kFixStaleTimeoutMilliseconds;
  38
  39   explicit GeolocationArbitratorImpl(GeolocationObserver* observer);
  40   virtual ~GeolocationArbitratorImpl();
  41
  42   static GURL DefaultNetworkProviderURL();
  43
  44   // GeolocationArbitrator
  45   virtual void StartProviders(const GeolocationObserverOptions& options)
  46       OVERRIDE;
  47   virtual void StopProviders() OVERRIDE;
  48   virtual void OnPermissionGranted() OVERRIDE;
  49   virtual bool HasPermissionBeenGranted() const OVERRIDE;
  50
  51   // ListenerInterface
  52   virtual void LocationUpdateAvailable(LocationProviderBase* provider) OVERRIDE;
  53
  54  protected:
  55
  56   AccessTokenStore* GetAccessTokenStore();
  57
  58   // These functions are useful for injection of dependencies in derived
  59   // testing classes.
  60   virtual AccessTokenStore* NewAccessTokenStore();
  61   virtual LocationProviderBase* NewNetworkLocationProvider(
  62       AccessTokenStore* access_token_store,
  63       net::URLRequestContextGetter* context,
  64       const GURL& url,
  65       const string16& access_token);
  66   virtual LocationProviderBase* NewSystemLocationProvider();
  67   virtual base::Time GetTimeNow() const;
  68
  69  private:
  70   // Takes ownership of |provider| on entry; it will either be added to
  71   // |providers_| or deleted on error (e.g. it fails to start).
  72   void RegisterProvider(LocationProviderBase* provider);
  73   void OnAccessTokenStoresLoaded(
  74       AccessTokenStore::AccessTokenSet access_token_store,
  75       net::URLRequestContextGetter* context_getter);
  76   void DoStartProviders();
  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   GeolocationObserver* observer_;
  86   ScopedVector<LocationProviderBase> providers_;
  87   GeolocationObserverOptions current_provider_options_;
  88   // The provider which supplied the current |position_|
  89   const LocationProviderBase* position_provider_;
  90   bool is_permission_granted_;
  91   // The current best estimate of our position.
  92   Geoposition position_;
  93
  94   DISALLOW_COPY_AND_ASSIGN(GeolocationArbitratorImpl);
  95 };
  96
  97 }  // namespace content
  98
  99 #endif  // CONTENT_BROWSER_GEOLOCATION_LOCATION_ARBITRATOR_IMPL_H_