// // detail/resolver_service_base.hpp // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2015 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_RESOLVER_SERVICE_BASE_HPP #define ASIO_DETAIL_RESOLVER_SERVICE_BASE_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include "asio/detail/config.hpp" #include "asio/error.hpp" #include "asio/io_context.hpp" #include "asio/detail/mutex.hpp" #include "asio/detail/noncopyable.hpp" #include "asio/detail/operation.hpp" #include "asio/detail/socket_ops.hpp" #include "asio/detail/socket_types.hpp" #include "asio/detail/scoped_ptr.hpp" #include "asio/detail/thread.hpp" #include "asio/detail/push_options.hpp" namespace asio { namespace detail { class resolver_service_base { public: // The implementation type of the resolver. A cancellation token is used to // indicate to the background thread that the operation has been cancelled. typedef socket_ops::shared_cancel_token_type implementation_type; // Constructor. ASIO_DECL resolver_service_base(asio::io_context& io_context); // Destructor. ASIO_DECL ~resolver_service_base(); // Destroy all user-defined handler objects owned by the service. ASIO_DECL void shutdown(); // Perform any fork-related housekeeping. ASIO_DECL void notify_fork( asio::io_context::fork_event fork_ev); // Construct a new resolver implementation. ASIO_DECL void construct(implementation_type& impl); // Destroy a resolver implementation. ASIO_DECL void destroy(implementation_type&); // Cancel pending asynchronous operations. ASIO_DECL void cancel(implementation_type& impl); protected: // Helper function to start an asynchronous resolve operation. ASIO_DECL void start_resolve_op(operation* op); #if !defined(ASIO_WINDOWS_RUNTIME) // Helper class to perform exception-safe cleanup of addrinfo objects. class auto_addrinfo : private asio::detail::noncopyable { public: explicit auto_addrinfo(asio::detail::addrinfo_type* ai) : ai_(ai) { } ~auto_addrinfo() { if (ai_) socket_ops::freeaddrinfo(ai_); } operator asio::detail::addrinfo_type*() { return ai_; } private: asio::detail::addrinfo_type* ai_; }; #endif // !defined(ASIO_WINDOWS_RUNTIME) // Helper class to run the work io_context in a thread. class work_io_context_runner; // Start the work thread if it's not already running. ASIO_DECL void start_work_thread(); // The io_context implementation used to post completions. io_context_impl& io_context_impl_; private: // Mutex to protect access to internal data. asio::detail::mutex mutex_; // Private io_context used for performing asynchronous host resolution. asio::detail::scoped_ptr<asio::io_context> work_io_context_; // The work io_context implementation used to post completions. io_context_impl& work_io_context_impl_; // Work for the private io_context to perform. asio::detail::scoped_ptr<asio::io_context::work> work_; // Thread used for running the work io_context's run loop. asio::detail::scoped_ptr<asio::detail::thread> work_thread_; }; } // namespace detail } // namespace asio #include "asio/detail/pop_options.hpp" #if defined(ASIO_HEADER_ONLY) # include "asio/detail/impl/resolver_service_base.ipp" #endif // defined(ASIO_HEADER_ONLY) #endif // ASIO_DETAIL_RESOLVER_SERVICE_BASE_HPP