content/browser/geolocation/geolocation_provider_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_GEOLOCATION_PROVIDER_IMPL_H_
   6 #define CONTENT_BROWSER_GEOLOCATION_GEOLOCATION_PROVIDER_IMPL_H_
   7
   8 #include <list>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "base/callback_forward.h"
  13 #include "base/compiler_specific.h"
  14 #include "base/threading/thread.h"
  15 #include "content/common/content_export.h"
  16 #include "content/public/browser/geolocation_provider.h"
  17 #include "content/public/common/geoposition.h"
  18
  19 template<typename Type> struct DefaultSingletonTraits;
  20
  21 namespace content {
  22 class LocationArbitrator;
  23
  24 // This is the main API to the geolocation subsystem. The application will hold
  25 // a single instance of this class and can register multiple clients to be
  26 // notified of location changes:
  27 // * Callbacks are registered by AddLocationUpdateCallback() and will keep
  28 //   receiving updates until unregistered by RemoveLocationUpdateCallback().
  29 // The application must instantiate the GeolocationProvider on the IO thread and
  30 // must communicate with it on the same thread.
  31 // The underlying location arbitrator will only be enabled whilst there is at
  32 // least one registered observer or pending callback. The arbitrator and the
  33 // location providers it uses run on a separate Geolocation thread.
  34 class CONTENT_EXPORT GeolocationProviderImpl
  35     : public NON_EXPORTED_BASE(GeolocationProvider),
  36       public base::Thread {
  37  public:
  38   // GeolocationProvider implementation:
  39   virtual void AddLocationUpdateCallback(const LocationUpdateCallback& callback,
  40                                          bool use_high_accuracy) OVERRIDE;
  41   virtual bool RemoveLocationUpdateCallback(
  42       const LocationUpdateCallback& callback) OVERRIDE;
  43   virtual void UserDidOptIntoLocationServices() OVERRIDE;
  44
  45   bool LocationServicesOptedIn() const;
  46
  47   // Overrides the location for automation/testing. Suppresses any further
  48   // updates from the actual providers and sends an update with the overridden
  49   // position to all registered clients.
  50   void OverrideLocationForTesting(const Geoposition& override_position);
  51
  52   // Callback from the LocationArbitrator. Public for testing.
  53   void OnLocationUpdate(const Geoposition& position);
  54
  55   // Gets a pointer to the singleton instance of the location relayer, which
  56   // is in turn bound to the browser's global context objects. This must only be
  57   // called on the IO thread so that the GeolocationProviderImpl is always
  58   // instantiated on the same thread. Ownership is NOT returned.
  59   static GeolocationProviderImpl* GetInstance();
  60
  61  protected:
  62   friend struct DefaultSingletonTraits<GeolocationProviderImpl>;
  63   GeolocationProviderImpl();
  64   virtual ~GeolocationProviderImpl();
  65
  66   // Useful for injecting mock geolocation arbitrator in tests.
  67   virtual LocationArbitrator* CreateArbitrator();
  68
  69  private:
  70   typedef std::pair<LocationUpdateCallback, bool> LocationUpdateInfo;
  71   typedef std::list<LocationUpdateInfo> CallbackList;
  72
  73   bool OnGeolocationThread() const;
  74
  75   // Start and stop providers as needed when clients are added or removed.
  76   void OnClientsChanged();
  77
  78   // Stops the providers when there are no more registered clients. Note that
  79   // once the Geolocation thread is started, it will stay alive (but sitting
  80   // idle without any pending messages).
  81   void StopProviders();
  82
  83   // Starts the geolocation providers or updates their options (delegates to
  84   // arbitrator).
  85   void StartProviders(bool use_high_accuracy);
  86
  87   // Updates the providers on the geolocation thread, which must be running.
  88   void InformProvidersPermissionGranted();
  89
  90   // Notifies all registered clients that a position update is available.
  91   void NotifyClients(const Geoposition& position);
  92
  93   // Thread
  94   virtual void Init() OVERRIDE;
  95   virtual void CleanUp() OVERRIDE;
  96
  97   // Only used on the IO thread
  98   CallbackList callbacks_;
  99   bool user_did_opt_into_location_services_;
 100   Geoposition position_;
 101
 102   // True only in testing, where we want to use a custom position.
 103   bool ignore_location_updates_;
 104
 105   // Only to be used on the geolocation thread.
 106   LocationArbitrator* arbitrator_;
 107
 108   DISALLOW_COPY_AND_ASSIGN(GeolocationProviderImpl);
 109 };
 110
 111 }  // namespace content
 112
 113 #endif  // CONTENT_BROWSER_GEOLOCATION_GEOLOCATION_PROVIDER_IMPL_H_