src/components/keyed_service/core/refcounted_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_CORE_REFCOUNTED_KEYED_SERVICE_FACTORY_H_
   6 #define COMPONENTS_KEYED_SERVICE_CORE_REFCOUNTED_KEYED_SERVICE_FACTORY_H_
   7
   8 #include <map>
   9
  10 #include "base/basictypes.h"
  11 #include "base/compiler_specific.h"
  12 #include "base/memory/ref_counted.h"
  13 #include "components/keyed_service/core/keyed_service_base_factory.h"
  14 #include "components/keyed_service/core/keyed_service_export.h"
  15
  16 class RefcountedKeyedService;
  17
  18 // A specialized KeyedServiceBaseFactory that manages a RefcountedThreadSafe<>.
  19 //
  20 // While the factory returns RefcountedThreadSafe<>s, the factory itself is a
  21 // base::NotThreadSafe. Only call methods on this object on the UI thread.
  22 //
  23 // Implementers of RefcountedKeyedService should note that we guarantee that
  24 // ShutdownOnUIThread() is called on the UI thread, but actual object
  25 // destruction can happen anywhere.
  26 class KEYED_SERVICE_EXPORT RefcountedKeyedServiceFactory
  27     : public KeyedServiceBaseFactory {
  28  protected:
  29   RefcountedKeyedServiceFactory(const char* name, DependencyManager* manager);
  30   ~RefcountedKeyedServiceFactory() override;
  31
  32   // A function that supplies the instance of a KeyedService for a given
  33   // |context|. This is used primarily for testing, where we want to feed
  34   // a specific mock into the KeyedServiceFactory system.
  35   typedef scoped_refptr<RefcountedKeyedService>(*TestingFactoryFunction)(
  36       base::SupportsUserData* context);
  37
  38   // Associates |factory| with |context| so that |factory| is used to create
  39   // the KeyedService when requested.  |factory| can be NULL to signal that
  40   // KeyedService should be NULL. Multiple calls to SetTestingFactory() are
  41   // allowed; previous services will be shut down.
  42   void SetTestingFactory(base::SupportsUserData* context,
  43                          TestingFactoryFunction factory);
  44
  45   // Associates |factory| with |context| and immediately returns the created
  46   // KeyedService. Since the factory will be used immediately, it may not be
  47   // NULL.
  48   scoped_refptr<RefcountedKeyedService> SetTestingFactoryAndUse(
  49       base::SupportsUserData* context,
  50       TestingFactoryFunction factory);
  51
  52   // Common implementation that maps |context| to some service object. Deals
  53   // with incognito contexts per subclass instructions with GetContextToUse()
  54   // method on the base.  If |create| is true, the service will be created
  55   // using BuildServiceInstanceFor() if it doesn't already exist.
  56   scoped_refptr<RefcountedKeyedService> GetServiceForContext(
  57       base::SupportsUserData* context,
  58       bool create);
  59
  60   // Maps |context| to |service| with debug checks to prevent duplication.
  61   void Associate(base::SupportsUserData* context,
  62                  const scoped_refptr<RefcountedKeyedService>& service);
  63
  64   // Returns a new RefcountedKeyedService that will be associated with
  65   // |context|.
  66   virtual scoped_refptr<RefcountedKeyedService> BuildServiceInstanceFor(
  67       base::SupportsUserData* context) const = 0;
  68
  69   // Returns whether the |context| is off-the-record or not.
  70   virtual bool IsOffTheRecord(base::SupportsUserData* context) const = 0;
  71
  72   // KeyedServiceBaseFactory:
  73   void ContextShutdown(base::SupportsUserData* context) override;
  74   void ContextDestroyed(base::SupportsUserData* context) override;
  75
  76   void SetEmptyTestingFactory(base::SupportsUserData* context) override;
  77   bool HasTestingFactory(base::SupportsUserData* context) override;
  78   void CreateServiceNow(base::SupportsUserData* context) override;
  79
  80  private:
  81   typedef std::map<base::SupportsUserData*,
  82                    scoped_refptr<RefcountedKeyedService>> KeyedServices;
  83   typedef std::map<base::SupportsUserData*, TestingFactoryFunction>
  84       OverriddenTestingFunctions;
  85
  86   // The mapping between a context and its refcounted service.
  87   KeyedServices mapping_;
  88
  89   // The mapping between a context and its overridden
  90   // TestingFactoryFunction.
  91   OverriddenTestingFunctions testing_factories_;
  92
  93   DISALLOW_COPY_AND_ASSIGN(RefcountedKeyedServiceFactory);
  94 };
  95
  96 #endif  // COMPONENTS_KEYED_SERVICE_CORE_REFCOUNTED_KEYED_SERVICE_FACTORY_H_