components/keyed_service/ios/browser_state_context_converter.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 #ifndef COMPONENTS_KEYED_SERVICE_IOS_BROWSER_STATE_CONTEXT_CONVERTER_H_
   6 #define COMPONENTS_KEYED_SERVICE_IOS_BROWSER_STATE_CONTEXT_CONVERTER_H_
   7
   8 #include "base/macros.h"
   9
  10 namespace base {
  11 class SupportsUserData;
  12 }
  13
  14 // BrowserStateContextConverter does safe conversion of base::SupportsUserData*
  15 // to web::BrowserState* or content::BrowserContext*.
  16 //
  17 // iOS code is still using BrowserContextKeyedServiceFactory and until the
  18 // conversion is complete — http://crbug.com/478763 — there is need to have
  19 // mixed dependency between BCKSF and BSKSF.
  20 //
  21 // The implementation has BrowserStateKeyedServiceFactory supporting a
  22 // BrowserContextDependencyManager as DependencyManager. Thus the context
  23 // parameter passed to the BrowserStateKeyedServiceFactory can either be
  24 // content::BrowserContext if the method is invoked by DependencyManager
  25 // or web::BrowserState if the method is invoked via the type-safe public
  26 // API.
  27 //
  28 // The public API of BrowserStateKeyedServiceFactory is type-safe (all
  29 // public method receive web::BrowserState for context object), so only
  30 // methods that take a base::SupportsUserData need to discriminate
  31 // between the two objects.
  32 class BrowserStateContextConverter {
  33  public:
  34   // Sets/Gets the global BrowserStateContextConverter instance. May return null
  35   // when mixed dependencies are disabled.
  36   static void SetInstance(BrowserStateContextConverter* instance);
  37   static BrowserStateContextConverter* GetInstance();
  38
  39   // Converts |context| to a web::BrowserState* and returns it casted as a
  40   // base::SupportsUserData*.
  41   virtual base::SupportsUserData* GetBrowserStateForContext(
  42       base::SupportsUserData* context) = 0;
  43   // Converts |context| to a content::BrowserContext* and returns it casted as a
  44   // base::SupportsUserData*.
  45   virtual base::SupportsUserData* GetBrowserContextForContext(
  46       base::SupportsUserData* context) = 0;
  47
  48  protected:
  49   BrowserStateContextConverter();
  50   virtual ~BrowserStateContextConverter();
  51
  52   DISALLOW_COPY_AND_ASSIGN(BrowserStateContextConverter);
  53 };
  54
  55 #endif  // COMPONENTS_KEYED_SERVICE_IOS_BROWSER_STATE_CONTEXT_CONVERTER_H_