Home | History | Annotate | Download | only in geolocation 
      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 
     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_
    108