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// 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_BASE_FACTORY_H_
#define COMPONENTS_KEYED_SERVICE_CORE_KEYED_SERVICE_BASE_FACTORY_H_
#include <set>
#include "base/sequence_checker.h"
#include "components/keyed_service/core/dependency_node.h"
#include "components/keyed_service/core/keyed_service_export.h"
class DependencyManager;
class PrefService;
namespace base {
class SupportsUserData;
}
namespace user_prefs {
class PrefRegistrySyncable;
}
// Base class for factories that take a base::SupportsUserData and return some
// service. Not for direct usage, instead use descendent classes that deal with
// more specific context objects.
//
// This object describes general dependency management between factories while
// direct subclasses react to lifecycle events and implement memory management.
class KEYED_SERVICE_EXPORT KeyedServiceBaseFactory : public DependencyNode {
public:
// Returns our name.
const char* name() const { return service_name_; }
protected:
KeyedServiceBaseFactory(const char* service_name, DependencyManager* manager);
virtual ~KeyedServiceBaseFactory();
// Registers preferences used in this service on the pref service associated
// with |context|. This is safe to be called multiple times because testing
// code can have multiple services of the same type attached to a single
// |context|. Only test code is allowed to call this method.
//
// TODO(gab): This method can be removed entirely when
// PrefService::DeprecatedGetPrefRegistry() is phased out.
void RegisterUserPrefsOnContextForTest(base::SupportsUserData* context);
// The main public interface for declaring dependencies between services
// created by factories.
void DependsOn(KeyedServiceBaseFactory* rhs);
// Runtime assertion to check if |context| is considered stale. Should be used
// by subclasses when accessing |context|.
void AssertContextWasntDestroyed(base::SupportsUserData* context) const;
// Marks |context| as live (i.e., not stale). This method can be called as a
// safeguard against |AssertContextWasntDestroyed()| checks going off due to
// |context| aliasing an instance from a prior construction (i.e., 0xWhatever
// might be created, be destroyed, and then a new object might be created at
// 0xWhatever).
void MarkContextLive(base::SupportsUserData* context);
// Calls RegisterProfilePrefs() after doing house keeping required to work
// alongside RegisterUserPrefsOnContextForTest().
// TODO(gab): This method can be replaced by RegisterProfilePrefs() directly
// once RegisterUserPrefsOnContextForTest() is phased out.
void RegisterPrefsIfNecessaryForContext(
base::SupportsUserData* context,
user_prefs::PrefRegistrySyncable* registry);
// Returns the |user_pref::PrefRegistrySyncable| associated with |context|.
// The way they are associated is controlled by the embedder.
user_prefs::PrefRegistrySyncable* GetAssociatedPrefRegistry(
base::SupportsUserData* context) const;
// Finds which context (if any) to use.
virtual base::SupportsUserData* GetContextToUse(
base::SupportsUserData* context) const = 0;
// By default, instance of a service are created lazily when GetForContext()
// is called by the subclass. Some services need to be created as soon as the
// context is created and should override this method to return true.
virtual bool ServiceIsCreatedWithContext() const;
// By default, testing contexts will be treated like normal contexts. If this
// method is overriden to return true, then the service associated with the
// testing context will be null.
virtual bool ServiceIsNULLWhileTesting() const;
// The service build by the factories goes through a two phase shutdown.
// It is up to the individual factory types to determine what this two pass
// shutdown means. The general framework guarantees the following:
//
// - Each ContextShutdown() is called in dependency order (and you may
// reach out to other services during this phase).
//
// - Each ContextDestroyed() is called in dependency order. Accessing a
// service with GetForContext() will NOTREACHED() and code should delete/
// deref/do other final memory management during this phase. The base class
// method *must* be called as the last thing.
virtual void ContextShutdown(base::SupportsUserData* context) = 0;
virtual void ContextDestroyed(base::SupportsUserData* context);
// Returns whether the preferences have been registered on this context.
bool ArePreferencesSetOn(base::SupportsUserData* context) const;
// Mark context has having preferences registered.
void MarkPreferencesSetOn(base::SupportsUserData* context);
SEQUENCE_CHECKER(sequence_checker_);
private:
friend class DependencyManager;
// The DependencyManager used. In real code, this will be a singleton used
// by all the factories of a given type. Unit tests will use their own copy.
DependencyManager* dependency_manager_;
// Registers any preferences used by this service.
virtual void RegisterPrefs(user_prefs::PrefRegistrySyncable* registry) {}
// Used by DependencyManager to disable creation of the service when the
// method ServiceIsNULLWhileTesting() returns true.
virtual void SetEmptyTestingFactory(base::SupportsUserData* context) = 0;
// Returns true if a testing factory function has been set for |context|.
virtual bool HasTestingFactory(base::SupportsUserData* context) = 0;
// Create the service associated with |context|.
virtual void CreateServiceNow(base::SupportsUserData* context) = 0;
// Contexts that have this service's preferences registered on them.
std::set<base::SupportsUserData*> registered_preferences_;
// A static string passed in to the constructor. Should be unique across all
// services.
const char* service_name_;
};
#endif // COMPONENTS_KEYED_SERVICE_CORE_KEYED_SERVICE_BASE_FACTORY_H_