polymorphic_handler.hpp

Go to the documentation of this file.

// Copyright (c) 2023 by Apex.AI Inc. All rights reserved.
// Copyright (c) 2025 Contributors to the Eclipse Foundation
//
// See the NOTICE file(s) distributed with this work for additional
// information regarding copyright ownership.
//
// This program and the accompanying materials are made available under the
// terms of the Apache Software License 2.0 which is available at
// https://www.apache.org/licenses/LICENSE-2.0, or the MIT license
// which is available at https://opensource.org/licenses/MIT.
//
// SPDX-License-Identifier: Apache-2.0 OR MIT
 
#ifndef IOX2_BB_DESIGN_POLYMORPHIC_HANDLER_HPP
#define IOX2_BB_DESIGN_POLYMORPHIC_HANDLER_HPP
 
#include "iox2/legacy/atomic.hpp"
#include "iox2/legacy/static_lifetime_guard.hpp"
 
#include <type_traits>
 
namespace iox2 {
namespace legacy {
namespace detail {
 
template <typename Interface>
struct DefaultHooks {
    [[noreturn]] static void onSetAfterFinalize(Interface& currentInstance, Interface& newInstance) noexcept;
};
 
} // namespace detail
 
template <typename Interface, typename Default, typename Hooks = detail::DefaultHooks<Interface>>
class PolymorphicHandler {
    static_assert(std::is_base_of<Interface, Default>::value, "Interface must be a base class of Default");
 
    using Self = PolymorphicHandler<Interface, Default, Hooks>;
    friend class StaticLifetimeGuard<Self>;
 
  public:
    static Interface& get() noexcept;
 
    template <typename Handler>
    static bool set(StaticLifetimeGuard<Handler> handlerGuard) noexcept;
 
    static bool reset() noexcept;
 
    static void finalize() noexcept;
 
    static StaticLifetimeGuard<Self> guard() noexcept;
 
  private:
    PolymorphicHandler() noexcept;
 
    static PolymorphicHandler& self() noexcept;
 
    static Default& getDefault() noexcept;
 
    static Interface* getCurrentRelaxed() noexcept;
 
    static Interface* getCurrentSync() noexcept;
 
    static bool setHandler(Interface& handler) noexcept;
 
    // should a defaultHandler be created, the guard prevents its destruction
    StaticLifetimeGuard<Default> m_defaultGuard;
    concurrent::Atomic<bool> m_isFinal { false };
    concurrent::Atomic<Interface*> m_current { nullptr };
};
 
} // namespace legacy
} // namespace iox2
 
#include "iox2/legacy/detail/polymorphic_handler.inl"
 
#endif // IOX2_BB_DESIGN_POLYMORPHIC_HANDLER_HPP