components/keyed_service/content/browser_context_keyed_service_factory.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_CONTENT_BROWSER_CONTEXT_KEYED_SERVICE_FACTORY_H_
   6 #define COMPONENTS_KEYED_SERVICE_CONTENT_BROWSER_CONTEXT_KEYED_SERVICE_FACTORY_H_
   7
   8 #include <map>
   9
  10 #include "base/basictypes.h"
  11 #include "base/compiler_specific.h"
  12 #include "components/keyed_service/content/browser_context_keyed_base_factory.h"
  13 #include "components/keyed_service/core/keyed_service.h"
  14 #include "components/keyed_service/core/keyed_service_export.h"
  15
  16 class BrowserContextDependencyManager;
  17 class KeyedService;
  18
  19 // Base class for Factories that take a BrowserContext object and return some
  20 // service on a one-to-one mapping. Each factory that derives from this class
  21 // *must* be a Singleton (only unit tests don't do that).
  22 //
  23 // We do this because services depend on each other and we need to control
  24 // shutdown/destruction order. In each derived classes' constructors, the
  25 // implementors must explicitly state which services are depended on.
  26 class KEYED_SERVICE_EXPORT BrowserContextKeyedServiceFactory
  27     : public BrowserContextKeyedBaseFactory {
  28  public:
  29   // A function that supplies the instance of a KeyedService for a given
  30   // BrowserContext. This is used primarily for testing, where we want to feed
  31   // a specific mock into the BCKSF system.
  32   typedef KeyedService* (*TestingFactoryFunction)(
  33       content::BrowserContext* context);
  34
  35   // Associates |factory| with |context| so that |factory| is used to create
  36   // the KeyedService when requested.  |factory| can be NULL to signal that
  37   // KeyedService should be NULL. Multiple calls to SetTestingFactory() are
  38   // allowed; previous services will be shut down.
  39   void SetTestingFactory(content::BrowserContext* context,
  40                          TestingFactoryFunction factory);
  41
  42   // Associates |factory| with |context| and immediately returns the created
  43   // KeyedService. Since the factory will be used immediately, it may not be
  44   // NULL.
  45   KeyedService* SetTestingFactoryAndUse(content::BrowserContext* context,
  46                                         TestingFactoryFunction factory);
  47
  48  protected:
  49   // BrowserContextKeyedServiceFactories must communicate with a
  50   // BrowserContextDependencyManager. For all non-test code, write your subclass
  51   // constructors like this:
  52   //
  53   //   MyServiceFactory::MyServiceFactory()
  54   //     : BrowserContextKeyedServiceFactory(
  55   //         "MyService",
  56   //         BrowserContextDependencyManager::GetInstance())
  57   //   {}
  58   BrowserContextKeyedServiceFactory(const char* name,
  59                                     BrowserContextDependencyManager* manager);
  60   virtual ~BrowserContextKeyedServiceFactory();
  61
  62   // Common implementation that maps |context| to some service object. Deals
  63   // with incognito contexts per subclass instructions with
  64   // GetBrowserContextRedirectedInIncognito() and
  65   // GetBrowserContextOwnInstanceInIncognito() through the
  66   // GetBrowserContextToUse() method on the base.  If |create| is true, the
  67   // service will be created using BuildServiceInstanceFor() if it doesn't
  68   // already exist.
  69   KeyedService* GetServiceForBrowserContext(content::BrowserContext* context,
  70                                             bool create);
  71
  72   // Maps |context| to |service| with debug checks to prevent duplication.
  73   void Associate(content::BrowserContext* context, KeyedService* service);
  74
  75   // Removes the mapping from |context| to a service.
  76   void Disassociate(content::BrowserContext* context);
  77
  78   // All subclasses of BrowserContextKeyedServiceFactory must return a
  79   // KeyedService instead of just a BrowserContextKeyedBase.
  80   virtual KeyedService* BuildServiceInstanceFor(
  81       content::BrowserContext* context) const = 0;
  82
  83   // A helper object actually listens for notifications about BrowserContext
  84   // destruction, calculates the order in which things are destroyed and then
  85   // does a two pass shutdown.
  86   //
  87   // First, BrowserContextShutdown() is called on every ServiceFactory and will
  88   // usually call KeyedService::Shutdown(), which gives each
  89   // KeyedService a chance to remove dependencies on other
  90   // services that it may be holding.
  91   //
  92   // Secondly, BrowserContextDestroyed() is called on every ServiceFactory
  93   // and the default implementation removes it from |mapping_| and deletes
  94   // the pointer.
  95   virtual void BrowserContextShutdown(content::BrowserContext* context)
  96       OVERRIDE;
  97   virtual void BrowserContextDestroyed(content::BrowserContext* context)
  98       OVERRIDE;
  99
 100   virtual void SetEmptyTestingFactory(content::BrowserContext* context)
 101       OVERRIDE;
 102   virtual bool HasTestingFactory(content::BrowserContext* context) OVERRIDE;
 103   virtual void CreateServiceNow(content::BrowserContext* context) OVERRIDE;
 104
 105  private:
 106   friend class BrowserContextDependencyManager;
 107   friend class BrowserContextDependencyManagerUnittests;
 108
 109   typedef std::map<content::BrowserContext*, KeyedService*>
 110       BrowserContextKeyedServices;
 111   typedef std::map<content::BrowserContext*, TestingFactoryFunction>
 112       BrowserContextOverriddenTestingFunctions;
 113
 114   // The mapping between a BrowserContext and its service.
 115   BrowserContextKeyedServices mapping_;
 116
 117   // The mapping between a BrowserContext and its overridden
 118   // TestingFactoryFunction.
 119   BrowserContextOverriddenTestingFunctions testing_factories_;
 120
 121   DISALLOW_COPY_AND_ASSIGN(BrowserContextKeyedServiceFactory);
 122 };
 123
 124 #endif  // COMPONENTS_KEYED_SERVICE_CONTENT_BROWSER_CONTEXT_KEYED_SERVICE_FACTORY_H_