// // service_registry.hpp // ~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2007 Christopher M. Kohlhoff (chris at kohlhoff dot com) // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #ifndef ASIO_DETAIL_SERVICE_REGISTRY_HPP #define ASIO_DETAIL_SERVICE_REGISTRY_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include "asio/detail/push_options.hpp" #include "asio/detail/push_options.hpp" #include #include #include "asio/detail/pop_options.hpp" #include "asio/io_service.hpp" #include "asio/detail/mutex.hpp" #include "asio/detail/noncopyable.hpp" #include "asio/detail/service_id.hpp" namespace asio { namespace detail { class service_registry : private noncopyable { public: // Constructor. service_registry(asio::io_service& o) : owner_(o), first_service_(0) { } // Destructor. ~service_registry() { // Shutdown all services. This must be done in a separate loop before the // services are destroyed since the destructors of user-defined handler // objects may try to access other service objects. asio::io_service::service* service = first_service_; while (service) { service->shutdown_service(); service = service->next_; } // Destroy all services. while (first_service_) { asio::io_service::service* next_service = first_service_->next_; delete first_service_; first_service_ = next_service; } } // Get the service object corresponding to the specified service type. Will // create a new service object automatically if no such object already // exists. Ownership of the service object is not transferred to the caller. template Service& use_service() { asio::detail::mutex::scoped_lock lock(mutex_); // First see if there is an existing service object for the given type. asio::io_service::service* service = first_service_; while (service) { if (service_id_matches(*service, Service::id)) return *static_cast(service); service = service->next_; } // Create a new service object. The service registry's mutex is not locked // at this time to allow for nested calls into this function from the new // service's constructor. lock.unlock(); std::auto_ptr new_service(new Service(owner_)); init_service_id(*new_service, Service::id); Service& new_service_ref = *new_service; lock.lock(); // Check that nobody else created another service object of the same type // while the lock was released. service = first_service_; while (service) { if (service_id_matches(*service, Service::id)) return *static_cast(service); service = service->next_; } // Service was successfully initialised, pass ownership to registry. new_service->next_ = first_service_; first_service_ = new_service.release(); return new_service_ref; } // Add a service object. Returns false on error, in which case ownership of // the object is retained by the caller. template bool add_service(Service* new_service) { asio::detail::mutex::scoped_lock lock(mutex_); // Check if there is an existing service object for the given type. asio::io_service::service* service = first_service_; while (service) { if (service_id_matches(*service, Service::id)) return false; service = service->next_; } // Take ownership of the service object. init_service_id(*new_service, Service::id); new_service->next_ = first_service_; first_service_ = new_service; return true; } // Check whether a service object of the specified type already exists. template bool has_service() const { asio::detail::mutex::scoped_lock lock(mutex_); asio::io_service::service* service = first_service_; while (service) { if (service_id_matches(*service, Service::id)) return true; service = service->next_; } return false; } private: // Set a service's id. void init_service_id(asio::io_service::service& service, const asio::io_service::id& id) { service.type_info_ = 0; service.id_ = &id; } // Set a service's id. template void init_service_id(asio::io_service::service& service, const asio::detail::service_id& /*id*/) { service.type_info_ = &typeid(Service); service.id_ = 0; } // Check if a service matches the given id. bool service_id_matches(const asio::io_service::service& service, const asio::io_service::id& id) { return service.id_ == &id; } // Check if a service matches the given id. template bool service_id_matches(const asio::io_service::service& service, const asio::detail::service_id& /*id*/) { return service.type_info_ != 0 && *service.type_info_ == typeid(Service); } // Mutex to protect access to internal data. mutable asio::detail::mutex mutex_; // The owner of this service registry and the services it contains. asio::io_service& owner_; // The first service in the list of contained services. asio::io_service::service* first_service_; }; } // namespace detail } // namespace asio #include "asio/detail/pop_options.hpp" #endif // ASIO_DETAIL_SERVICE_REGISTRY_HPP