wait_handler.hpp 2.8 KB

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  1. //
  2. // detail/wait_handler.hpp
  3. // ~~~~~~~~~~~~~~~~~~~~~~~
  4. //
  5. // Copyright (c) 2003-2021 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_WAIT_HANDLER_HPP
  11. #define BOOST_ASIO_DETAIL_WAIT_HANDLER_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. #include <boost/asio/detail/bind_handler.hpp>
  17. #include <boost/asio/detail/fenced_block.hpp>
  18. #include <boost/asio/detail/handler_alloc_helpers.hpp>
  19. #include <boost/asio/detail/handler_work.hpp>
  20. #include <boost/asio/detail/memory.hpp>
  21. #include <boost/asio/detail/wait_op.hpp>
  22. #include <boost/asio/detail/push_options.hpp>
  23. namespace boost {
  24. namespace asio {
  25. namespace detail {
  26. template <typename Handler, typename IoExecutor>
  27. class wait_handler : public wait_op
  28. {
  29. public:
  30. BOOST_ASIO_DEFINE_HANDLER_PTR(wait_handler);
  31. wait_handler(Handler& h, const IoExecutor& io_ex)
  32. : wait_op(&wait_handler::do_complete),
  33. handler_(BOOST_ASIO_MOVE_CAST(Handler)(h)),
  34. work_(handler_, io_ex)
  35. {
  36. }
  37. static void do_complete(void* owner, operation* base,
  38. const boost::system::error_code& /*ec*/,
  39. std::size_t /*bytes_transferred*/)
  40. {
  41. // Take ownership of the handler object.
  42. wait_handler* h(static_cast<wait_handler*>(base));
  43. ptr p = { boost::asio::detail::addressof(h->handler_), h, h };
  44. BOOST_ASIO_HANDLER_COMPLETION((*h));
  45. // Take ownership of the operation's outstanding work.
  46. handler_work<Handler, IoExecutor> w(
  47. BOOST_ASIO_MOVE_CAST2(handler_work<Handler, IoExecutor>)(
  48. h->work_));
  49. // Make a copy of the handler so that the memory can be deallocated before
  50. // the upcall is made. Even if we're not about to make an upcall, a
  51. // sub-object of the handler may be the true owner of the memory associated
  52. // with the handler. Consequently, a local copy of the handler is required
  53. // to ensure that any owning sub-object remains valid until after we have
  54. // deallocated the memory here.
  55. detail::binder1<Handler, boost::system::error_code>
  56. handler(h->handler_, h->ec_);
  57. p.h = boost::asio::detail::addressof(handler.handler_);
  58. p.reset();
  59. // Make the upcall if required.
  60. if (owner)
  61. {
  62. fenced_block b(fenced_block::half);
  63. BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_));
  64. w.complete(handler, handler.handler_);
  65. BOOST_ASIO_HANDLER_INVOCATION_END;
  66. }
  67. }
  68. private:
  69. Handler handler_;
  70. handler_work<Handler, IoExecutor> work_;
  71. };
  72. } // namespace detail
  73. } // namespace asio
  74. } // namespace boost
  75. #include <boost/asio/detail/pop_options.hpp>
  76. #endif // BOOST_ASIO_DETAIL_WAIT_HANDLER_HPP