Cleaner organization of WifiDataProvider code.

content/browser/geolocation/wifi_data_provider_manager.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // A wifi data provider provides wifi data from the device that is used by a
 // NetworkLocationProvider to obtain a position fix. We use a singleton
-// instance of the wifi data provider, which is used by multiple
+// instance of the wifi data provider manager, which is used by multiple
 // NetworkLocationProvider objects.
 //
-// This file provides WifiDataProvider, which provides static methods to
+// This file provides WifiDataProviderManager, which provides static methods to
 // access the singleton instance. The singleton instance uses a private
-// implementation to abstract across platforms and also to allow mock providers
-// to be used for testing.
-//
-// This file also provides WifiDataProviderImplBase, a base class which
-// provides common functionality for the private implementations.
+// implementation of WifiDataProvider to abstract across platforms and also to
+// allow mock providers to be used for testing.
 
-#ifndef CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_H_
-#define CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_H_
+#ifndef CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_MANAGER_H_
+#define CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_MANAGER_H_
 
 #include <set>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_util.h"
 #include "content/browser/geolocation/wifi_data.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 class WifiDataProvider;
 
-// See class WifiDataProvider for the public client API.
-// WifiDataProvider uses containment to hide platform-specific implementation
-// details from common code. This class provides common functionality for these
-// contained implementation classes. This is a modified pimpl pattern.
-class CONTENT_EXPORT WifiDataProviderImplBase
-    : public base::RefCountedThreadSafe<WifiDataProviderImplBase> {
- public:
-  WifiDataProviderImplBase();
-
-  // Tells the provider to start looking for data. Callbacks will start
-  // receiving notifications after this call.
-  virtual void StartDataProvider() = 0;
-
-  // Tells the provider to stop looking for data. Callbacks will stop
-  // receiving notifications after this call.
-  virtual void StopDataProvider() = 0;
-
-  // Provides whatever data the provider has, which may be nothing. Return
-  // value indicates whether this is all the data the provider could ever
-  // obtain.
-  virtual bool GetData(WifiData* data) = 0;
-
-  // Sets the container of this class, which is of type WifiDataProvider.
-  // This is required to pass as a parameter when calling a callback.
-  void SetContainer(WifiDataProvider* container);
-
-  typedef base::Callback<void(WifiDataProvider*)> WifiDataUpdateCallback;
-
-  void AddCallback(WifiDataUpdateCallback* callback);
-
-  bool RemoveCallback(WifiDataUpdateCallback* callback);
-
-  bool has_callbacks() const;
-
- protected:
-  friend class base::RefCountedThreadSafe<WifiDataProviderImplBase>;
-  virtual ~WifiDataProviderImplBase();
-
-  typedef std::set<WifiDataUpdateCallback*> CallbackSet;
-
-  // Runs all callbacks via a posted task, so we can unwind callstack here and
-  // avoid client reentrancy.
-  void RunCallbacks();
-
-  bool CalledOnClientThread() const;
-
-  base::MessageLoop* client_loop() const;
-
- private:
-  void DoRunCallbacks();
-
-  WifiDataProvider* container_;
-
-  // Reference to the client's message loop. All callbacks should happen in this
-  // context.
-  base::MessageLoop* client_loop_;
-
-  CallbackSet callbacks_;
-
-  DISALLOW_COPY_AND_ASSIGN(WifiDataProviderImplBase);
-};
-
-// A wifi data provider
+// A manager for wifi data providers.
 //
 // We use a singleton instance of this class which is shared by multiple network
 // location providers. These location providers access the instance through the
 // Register and Unregister methods.
-class CONTENT_EXPORT WifiDataProvider {
+class CONTENT_EXPORT WifiDataProviderManager {
  public:
   // Sets the factory function which will be used by Register to create the
   // implementation used by the singleton instance. This factory approach is
   // used both to abstract accross platform-specific implementations and to
   // inject mock implementations for testing.
-  typedef WifiDataProviderImplBase* (*ImplFactoryFunction)(void);
+  typedef WifiDataProvider* (*ImplFactoryFunction)(void);
   static void SetFactory(ImplFactoryFunction factory_function_in);
 
   // Resets the factory function to the default.
   static void ResetFactory();
 
-  typedef base::Callback<void(WifiDataProvider*)> WifiDataUpdateCallback;
+  typedef base::Callback<void(WifiDataProviderManager*)> WifiDataUpdateCallback;
 
   // Registers a callback, which will be run whenever new data is available.
   // Instantiates the singleton if necessary, and always returns it.
-  static WifiDataProvider* Register(WifiDataUpdateCallback* callback);
+  static WifiDataProviderManager* Register(WifiDataUpdateCallback* callback);
 
   // Removes a callback. If this is the last callback, deletes the singleton
   // instance. Return value indicates success.
   static bool Unregister(WifiDataUpdateCallback* callback);
 
   // Provides whatever data the provider has, which may be nothing. Return
   // value indicates whether this is all the data the provider could ever
   // obtain.
   bool GetData(WifiData* data);
 
  private:
   // Private constructor and destructor, callers access singleton through
   // Register and Unregister.
-  WifiDataProvider();
-  virtual ~WifiDataProvider();
+  WifiDataProviderManager();
+  ~WifiDataProviderManager();
 
   void AddCallback(WifiDataUpdateCallback* callback);
   bool RemoveCallback(WifiDataUpdateCallback* callback);
   bool has_callbacks() const;
 
   void StartDataProvider();
   void StopDataProvider();
 
-  static WifiDataProviderImplBase* DefaultFactoryFunction();
+  static WifiDataProvider* DefaultFactoryFunction();
 
   // The singleton-like instance of this class. (Not 'true' singleton, as it
   // may go through multiple create/destroy/create cycles per process instance,
   // e.g. when under test).
-  static WifiDataProvider* instance_;
+  static WifiDataProviderManager* instance_;
 
   // The factory function used to create the singleton instance.
   static ImplFactoryFunction factory_function_;
 
   // The internal implementation.
-  scoped_refptr<WifiDataProviderImplBase> impl_;
+  scoped_refptr<WifiDataProvider> impl_;
 
-  DISALLOW_COPY_AND_ASSIGN(WifiDataProvider);
+  DISALLOW_COPY_AND_ASSIGN(WifiDataProviderManager);
 };
 
 }  // namespace content
 
-#endif  // CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_H_
+#endif  // CONTENT_BROWSER_GEOLOCATION_WIFI_DATA_PROVIDER_MANAGER_H_