select_reactor.hpp 11 KB

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  1. //
  2. // detail/select_reactor.hpp
  3. // ~~~~~~~~~~~~~~~~~~~~~~~~~
  4. //
  5. // Copyright (c) 2003-2025 Christopher M. Kohlhoff (chris at kohlhoff dot com)
  6. //
  7. // Distributed under the Boost Software License, Version 1.0. (See accompanying
  8. // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  9. //
  10. #ifndef BOOST_ASIO_DETAIL_SELECT_REACTOR_HPP
  11. #define BOOST_ASIO_DETAIL_SELECT_REACTOR_HPP
  12. #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  13. # pragma once
  14. #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  15. #include <boost/asio/detail/config.hpp>
  16. #if defined(BOOST_ASIO_HAS_IOCP) \
  17. || (!defined(BOOST_ASIO_HAS_DEV_POLL) \
  18. && !defined(BOOST_ASIO_HAS_EPOLL) \
  19. && !defined(BOOST_ASIO_HAS_KQUEUE) \
  20. && !defined(BOOST_ASIO_WINDOWS_RUNTIME))
  21. #include <cstddef>
  22. #include <boost/asio/detail/fd_set_adapter.hpp>
  23. #include <boost/asio/detail/limits.hpp>
  24. #include <boost/asio/detail/mutex.hpp>
  25. #include <boost/asio/detail/op_queue.hpp>
  26. #include <boost/asio/detail/reactor_op.hpp>
  27. #include <boost/asio/detail/reactor_op_queue.hpp>
  28. #include <boost/asio/detail/scheduler_task.hpp>
  29. #include <boost/asio/detail/select_interrupter.hpp>
  30. #include <boost/asio/detail/socket_types.hpp>
  31. #include <boost/asio/detail/timer_queue_base.hpp>
  32. #include <boost/asio/detail/timer_queue_set.hpp>
  33. #include <boost/asio/detail/wait_op.hpp>
  34. #include <boost/asio/execution_context.hpp>
  35. #if defined(BOOST_ASIO_HAS_IOCP)
  36. # include <boost/asio/detail/thread.hpp>
  37. #endif // defined(BOOST_ASIO_HAS_IOCP)
  38. #include <boost/asio/detail/push_options.hpp>
  39. namespace boost {
  40. namespace asio {
  41. namespace detail {
  42. class select_reactor
  43. : public execution_context_service_base<select_reactor>
  44. #if !defined(BOOST_ASIO_HAS_IOCP)
  45. , public scheduler_task
  46. #endif // !defined(BOOST_ASIO_HAS_IOCP)
  47. {
  48. public:
  49. #if defined(BOOST_ASIO_WINDOWS) || defined(__CYGWIN__)
  50. enum op_types { read_op = 0, write_op = 1, except_op = 2,
  51. max_select_ops = 3, connect_op = 3, max_ops = 4 };
  52. #else // defined(BOOST_ASIO_WINDOWS) || defined(__CYGWIN__)
  53. enum op_types { read_op = 0, write_op = 1, except_op = 2,
  54. max_select_ops = 3, connect_op = 1, max_ops = 3 };
  55. #endif // defined(BOOST_ASIO_WINDOWS) || defined(__CYGWIN__)
  56. // Per-descriptor data.
  57. struct per_descriptor_data
  58. {
  59. };
  60. // Constructor.
  61. BOOST_ASIO_DECL select_reactor(boost::asio::execution_context& ctx);
  62. // Destructor.
  63. BOOST_ASIO_DECL ~select_reactor();
  64. // Destroy all user-defined handler objects owned by the service.
  65. BOOST_ASIO_DECL void shutdown();
  66. // Recreate internal descriptors following a fork.
  67. BOOST_ASIO_DECL void notify_fork(
  68. boost::asio::execution_context::fork_event fork_ev);
  69. // Initialise the task, but only if the reactor is not in its own thread.
  70. BOOST_ASIO_DECL void init_task();
  71. // Register a socket with the reactor. Returns 0 on success, system error
  72. // code on failure.
  73. BOOST_ASIO_DECL int register_descriptor(socket_type, per_descriptor_data&);
  74. // Register a descriptor with an associated single operation. Returns 0 on
  75. // success, system error code on failure.
  76. BOOST_ASIO_DECL int register_internal_descriptor(
  77. int op_type, socket_type descriptor,
  78. per_descriptor_data& descriptor_data, reactor_op* op);
  79. // Post a reactor operation for immediate completion.
  80. void post_immediate_completion(operation* op, bool is_continuation) const;
  81. // Post a reactor operation for immediate completion.
  82. BOOST_ASIO_DECL static void call_post_immediate_completion(
  83. operation* op, bool is_continuation, const void* self);
  84. // Start a new operation. The reactor operation will be performed when the
  85. // given descriptor is flagged as ready, or an error has occurred.
  86. BOOST_ASIO_DECL void start_op(int op_type, socket_type descriptor,
  87. per_descriptor_data&, reactor_op* op, bool is_continuation, bool,
  88. void (*on_immediate)(operation*, bool, const void*),
  89. const void* immediate_arg);
  90. // Start a new operation. The reactor operation will be performed when the
  91. // given descriptor is flagged as ready, or an error has occurred.
  92. void start_op(int op_type, socket_type descriptor,
  93. per_descriptor_data& descriptor_data, reactor_op* op,
  94. bool is_continuation, bool allow_speculative)
  95. {
  96. start_op(op_type, descriptor, descriptor_data,
  97. op, is_continuation, allow_speculative,
  98. &select_reactor::call_post_immediate_completion, this);
  99. }
  100. // Cancel all operations associated with the given descriptor. The
  101. // handlers associated with the descriptor will be invoked with the
  102. // operation_aborted error.
  103. BOOST_ASIO_DECL void cancel_ops(socket_type descriptor, per_descriptor_data&);
  104. // Cancel all operations associated with the given descriptor and key. The
  105. // handlers associated with the descriptor will be invoked with the
  106. // operation_aborted error.
  107. BOOST_ASIO_DECL void cancel_ops_by_key(socket_type descriptor,
  108. per_descriptor_data& descriptor_data,
  109. int op_type, void* cancellation_key);
  110. // Cancel any operations that are running against the descriptor and remove
  111. // its registration from the reactor. The reactor resources associated with
  112. // the descriptor must be released by calling cleanup_descriptor_data.
  113. BOOST_ASIO_DECL void deregister_descriptor(socket_type descriptor,
  114. per_descriptor_data&, bool closing);
  115. // Remove the descriptor's registration from the reactor. The reactor
  116. // resources associated with the descriptor must be released by calling
  117. // cleanup_descriptor_data.
  118. BOOST_ASIO_DECL void deregister_internal_descriptor(
  119. socket_type descriptor, per_descriptor_data&);
  120. // Perform any post-deregistration cleanup tasks associated with the
  121. // descriptor data.
  122. BOOST_ASIO_DECL void cleanup_descriptor_data(per_descriptor_data&);
  123. // Move descriptor registration from one descriptor_data object to another.
  124. BOOST_ASIO_DECL void move_descriptor(socket_type descriptor,
  125. per_descriptor_data& target_descriptor_data,
  126. per_descriptor_data& source_descriptor_data);
  127. // Add a new timer queue to the reactor.
  128. template <typename TimeTraits, typename Allocator>
  129. void add_timer_queue(timer_queue<TimeTraits, Allocator>& queue);
  130. // Remove a timer queue from the reactor.
  131. template <typename TimeTraits, typename Allocator>
  132. void remove_timer_queue(timer_queue<TimeTraits, Allocator>& queue);
  133. // Schedule a new operation in the given timer queue to expire at the
  134. // specified absolute time.
  135. template <typename TimeTraits, typename Allocator>
  136. void schedule_timer(timer_queue<TimeTraits, Allocator>& queue,
  137. const typename TimeTraits::time_type& time,
  138. typename timer_queue<TimeTraits, Allocator>::per_timer_data& timer,
  139. wait_op* op);
  140. // Cancel the timer operations associated with the given token. Returns the
  141. // number of operations that have been posted or dispatched.
  142. template <typename TimeTraits, typename Allocator>
  143. std::size_t cancel_timer(timer_queue<TimeTraits, Allocator>& queue,
  144. typename timer_queue<TimeTraits, Allocator>::per_timer_data& timer,
  145. std::size_t max_cancelled = (std::numeric_limits<std::size_t>::max)());
  146. // Cancel the timer operations associated with the given key.
  147. template <typename TimeTraits, typename Allocator>
  148. void cancel_timer_by_key(timer_queue<TimeTraits, Allocator>& queue,
  149. typename timer_queue<TimeTraits, Allocator>::per_timer_data* timer,
  150. void* cancellation_key);
  151. // Move the timer operations associated with the given timer.
  152. template <typename TimeTraits, typename Allocator>
  153. void move_timer(timer_queue<TimeTraits, Allocator>& queue,
  154. typename timer_queue<TimeTraits, Allocator>::per_timer_data& target,
  155. typename timer_queue<TimeTraits, Allocator>::per_timer_data& source);
  156. // Run select once until interrupted or events are ready to be dispatched.
  157. BOOST_ASIO_DECL void run(long usec, op_queue<operation>& ops);
  158. // Interrupt the select loop.
  159. BOOST_ASIO_DECL void interrupt();
  160. private:
  161. #if defined(BOOST_ASIO_HAS_IOCP)
  162. // Run the select loop in the thread.
  163. BOOST_ASIO_DECL void run_thread();
  164. #endif // defined(BOOST_ASIO_HAS_IOCP)
  165. // Helper function to add a new timer queue.
  166. BOOST_ASIO_DECL void do_add_timer_queue(timer_queue_base& queue);
  167. // Helper function to remove a timer queue.
  168. BOOST_ASIO_DECL void do_remove_timer_queue(timer_queue_base& queue);
  169. // Get the timeout value for the select call.
  170. BOOST_ASIO_DECL timeval* get_timeout(long usec, timeval& tv);
  171. // Cancel all operations associated with the given descriptor. This function
  172. // does not acquire the select_reactor's mutex.
  173. BOOST_ASIO_DECL void cancel_ops_unlocked(socket_type descriptor,
  174. const boost::system::error_code& ec);
  175. // The scheduler implementation used to post completions.
  176. # if defined(BOOST_ASIO_HAS_IOCP)
  177. typedef class win_iocp_io_context scheduler_type;
  178. # else // defined(BOOST_ASIO_HAS_IOCP)
  179. typedef class scheduler scheduler_type;
  180. # endif // defined(BOOST_ASIO_HAS_IOCP)
  181. scheduler_type& scheduler_;
  182. // Mutex to protect access to internal data.
  183. boost::asio::detail::mutex mutex_;
  184. // The interrupter is used to break a blocking select call.
  185. select_interrupter interrupter_;
  186. // The queues of read, write and except operations.
  187. reactor_op_queue<socket_type> op_queue_[max_ops];
  188. // The file descriptor sets to be passed to the select system call.
  189. fd_set_adapter fd_sets_[max_select_ops];
  190. // The timer queues.
  191. timer_queue_set timer_queues_;
  192. #if defined(BOOST_ASIO_HAS_IOCP)
  193. // Helper class to run the reactor loop in a thread.
  194. class thread_function;
  195. friend class thread_function;
  196. // Does the reactor loop thread need to stop.
  197. bool stop_thread_;
  198. // The thread that is running the reactor loop.
  199. boost::asio::detail::thread thread_;
  200. // Helper class to join and restart the reactor thread.
  201. class restart_reactor : public operation
  202. {
  203. public:
  204. restart_reactor(select_reactor* r)
  205. : operation(&restart_reactor::do_complete),
  206. reactor_(r)
  207. {
  208. }
  209. BOOST_ASIO_DECL static void do_complete(void* owner, operation* base,
  210. const boost::system::error_code& ec, std::size_t bytes_transferred);
  211. private:
  212. select_reactor* reactor_;
  213. };
  214. friend class restart_reactor;
  215. // Operation used to join and restart the reactor thread.
  216. restart_reactor restart_reactor_;
  217. #endif // defined(BOOST_ASIO_HAS_IOCP)
  218. // Whether the service has been shut down.
  219. bool shutdown_;
  220. };
  221. } // namespace detail
  222. } // namespace asio
  223. } // namespace boost
  224. #include <boost/asio/detail/pop_options.hpp>
  225. #include <boost/asio/detail/impl/select_reactor.hpp>
  226. #if defined(BOOST_ASIO_HEADER_ONLY)
  227. # include <boost/asio/detail/impl/select_reactor.ipp>
  228. #endif // defined(BOOST_ASIO_HEADER_ONLY)
  229. #endif // defined(BOOST_ASIO_HAS_IOCP)
  230. // || (!defined(BOOST_ASIO_HAS_DEV_POLL)
  231. // && !defined(BOOST_ASIO_HAS_EPOLL)
  232. // && !defined(BOOST_ASIO_HAS_KQUEUE)
  233. // && !defined(BOOST_ASIO_WINDOWS_RUNTIME))
  234. #endif // BOOST_ASIO_DETAIL_SELECT_REACTOR_HPP