Refactor (Refcounted)BrowserContextKeyedServiceFactory

components/keyed_service/core/keyed_service_factory.h

+// Copyright 2014 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.
+
+#ifndef COMPONENTS_KEYED_SERVICE_CORE_KEYED_SERVICE_FACTORY_H_
+#define COMPONENTS_KEYED_SERVICE_CORE_KEYED_SERVICE_FACTORY_H_
+
+#include <map>
+
+#include "base/basictypes.h"
+#include "base/callback_forward.h"
+#include "base/compiler_specific.h"
+#include "components/keyed_service/core/keyed_service_base_factory.h"
+#include "components/keyed_service/core/keyed_service_export.h"
+
+class DependencyManager;
+class KeyedService;
+
+// Base class for Factories that take a base::SupportsUserData object and return
+// some service on a one-to-one mapping. Each concrete factory that derives from
+// this class *must* be a Singleton (only unit tests don't do that).
+//
+// We do this because services depend on each other and we need to control
+// shutdown/destruction order. In each derived classes' constructors, the
+// implementors must explicitly state which services are depended on.
+class KEYED_SERVICE_EXPORT KeyedServiceFactory
+    : public KeyedServiceBaseFactory {
+ protected:
+  KeyedServiceFactory(const char* name, DependencyManager* manager);
+  ~KeyedServiceFactory() override;
+
+  // A function that supplies the instance of a KeyedService for a given
+  // |context|. This is used primarily for testing, where we want to feed
+  // a specific mock into the KeyedServiceFactory system.
+  typedef KeyedService* (*TestingFactoryFunction)(
+      base::SupportsUserData* context);
+
+  // Associates |factory| with |context| so that |factory| is used to create
+  // the KeyedService when requested.  |factory| can be NULL to signal that
+  // KeyedService should be NULL. Multiple calls to SetTestingFactory() are
+  // allowed; previous services will be shut down.
+  void SetTestingFactory(base::SupportsUserData* context,
+                         TestingFactoryFunction factory);
+
+  // Associates |factory| with |context| and immediately returns the created
+  // KeyedService. Since the factory will be used immediately, it may not be
+  // NULL.
+  KeyedService* SetTestingFactoryAndUse(base::SupportsUserData* context,
+                                        TestingFactoryFunction factory);
+
+  // Common implementation that maps |context| to some service object. Deals
+  // with incognito contexts per subclass instructions with GetContextToUse()
+  // method on the base.  If |create| is true, the service will be created
+  // using BuildServiceInstanceFor() if it doesn't already exist.
+  KeyedService* GetServiceForContext(base::SupportsUserData* context,
+                                     bool create);
+
+  // Maps |context| to |service| with debug checks to prevent duplication.
+  void Associate(base::SupportsUserData* context, KeyedService* service);
+
+  // Removes the mapping from |context| to a service.
+  void Disassociate(base::SupportsUserData* context);
+
+  // Returns a new KeyedService that will be associated with |context|.
+  virtual KeyedService* BuildServiceInstanceFor(
+      base::SupportsUserData* context) const = 0;
+
+  // Returns whether the |context| is off-the-record or not.
+  virtual bool IsOffTheRecord(base::SupportsUserData* context) const = 0;
+
+  // KeyedServiceBaseFactory:
+  void ContextShutdown(base::SupportsUserData* context) override;
+  void ContextDestroyed(base::SupportsUserData* context) override;
+
+  void SetEmptyTestingFactory(base::SupportsUserData* context) override;
+  bool HasTestingFactory(base::SupportsUserData* context) override;
+  void CreateServiceNow(base::SupportsUserData* context) override;
+
+ private:
+  friend class DependencyManager;
+  friend class DependencyManagerUnittests;
+
+  typedef std::map<base::SupportsUserData*, KeyedService*> KeyedServices;
+  typedef std::map<base::SupportsUserData*, TestingFactoryFunction>
+      OverriddenTestingFunctions;
+
+  // The mapping between a context and its service.
+  KeyedServices mapping_;
+
+  // The mapping between a context and its overridden
+  // TestingFactoryFunction.
+  OverriddenTestingFunctions testing_factories_;
+
+  DISALLOW_COPY_AND_ASSIGN(KeyedServiceFactory);
+};
+
+#endif  // COMPONENTS_KEYED_SERVICE_CORE_KEYED_SERVICE_FACTORY_H_