content/browser/geolocation/wifi_data_provider_manager.h

   1 // Copyright 2014 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 // A wifi data provider provides wifi data from the device that is used by a
   6 // NetworkLocationProvider to obtain a position fix. We use a singleton
   7 // instance of the wifi data provider manager, which is used by multiple
   8 // NetworkLocationProvider objects.
   9 //
  10 // This file provides WifiDataProviderManager, which provides static methods to
  11 // access the singleton instance. The singleton instance uses a private
  12 // implementation of WifiDataProvider to abstract across platforms and also to
  13 // allow mock providers to be used for testing.
  14
  15 #ifndef CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_MANAGER_H_
  16 #define CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_MANAGER_H_
  17
  18 #include <set>
  19
  20 #include "base/basictypes.h"
  21 #include "base/bind.h"
  22 #include "base/callback.h"
  23 #include "base/memory/ref_counted.h"
  24 #include "base/message_loop/message_loop.h"
  25 #include "base/strings/string16.h"
  26 #include "base/strings/string_util.h"
  27 #include "content/browser/geolocation/wifi_data.h"
  28 #include "content/common/content_export.h"
  29
  30 namespace content {
  31
  32 class WifiDataProvider;
  33
  34 // A manager for wifi data providers.
  35 //
  36 // We use a singleton instance of this class which is shared by multiple network
  37 // location providers. These location providers access the instance through the
  38 // Register and Unregister methods.
  39 class CONTENT_EXPORT WifiDataProviderManager {
  40  public:
  41   typedef WifiDataProvider* (*ImplFactoryFunction)(void);
  42
  43   // Sets the factory function which will be used by Register to create the
  44   // implementation used by the singleton instance. This factory approach is
  45   // used both to abstract accross platform-specific implementations and to
  46   // inject mock implementations for testing.
  47   static void SetFactoryForTesting(ImplFactoryFunction factory_function_in);
  48
  49   // Resets the factory function to the default.
  50   static void ResetFactoryForTesting();
  51
  52   typedef base::Closure WifiDataUpdateCallback;
  53
  54   // Registers a callback, which will be run whenever new data is available.
  55   // Instantiates the singleton if necessary, and always returns it.
  56   static WifiDataProviderManager* Register(WifiDataUpdateCallback* callback);
  57
  58   // Removes a callback. If this is the last callback, deletes the singleton
  59   // instance. Return value indicates success.
  60   static bool Unregister(WifiDataUpdateCallback* callback);
  61
  62   // Provides whatever data the provider has, which may be nothing. Return
  63   // value indicates whether this is all the data the provider could ever
  64   // obtain.
  65   bool GetData(WifiData* data);
  66
  67  private:
  68   // Private constructor and destructor, callers access singleton through
  69   // Register and Unregister.
  70   WifiDataProviderManager();
  71   ~WifiDataProviderManager();
  72
  73   void AddCallback(WifiDataUpdateCallback* callback);
  74   bool RemoveCallback(WifiDataUpdateCallback* callback);
  75   bool has_callbacks() const;
  76
  77   void StartDataProvider();
  78   void StopDataProvider();
  79
  80   static WifiDataProvider* DefaultFactoryFunction();
  81
  82   // The singleton-like instance of this class. (Not 'true' singleton, as it
  83   // may go through multiple create/destroy/create cycles per process instance,
  84   // e.g. when under test).
  85   static WifiDataProviderManager* instance_;
  86
  87   // The factory function used to create the singleton instance.
  88   static ImplFactoryFunction factory_function_;
  89
  90   // The internal implementation.
  91   scoped_refptr<WifiDataProvider> impl_;
  92
  93   DISALLOW_COPY_AND_ASSIGN(WifiDataProviderManager);
  94 };
  95
  96 }  // namespace content
  97
  98 #endif  // CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_MANAGER_H_