ceph/src/boost/boost/asio/detail/handler_work.hpp

   1 //
   2 // detail/handler_work.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2020 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
  11 #ifndef BOOST_ASIO_DETAIL_HANDLER_WORK_HPP
  12 #define BOOST_ASIO_DETAIL_HANDLER_WORK_HPP
  13
  14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  15 # pragma once
  16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  17
  18 #include <boost/asio/detail/config.hpp>
  19 #include <boost/asio/associated_executor.hpp>
  20 #include <boost/asio/detail/handler_invoke_helpers.hpp>
  21
  22 #include <boost/asio/detail/push_options.hpp>
  23
  24 namespace boost {
  25 namespace asio {
  26 namespace detail {
  27
  28 // A helper class template to allow completion handlers to be dispatched
  29 // through either the new executors framework or the old invocaton hook. The
  30 // primary template uses the new executors framework.
  31 template <typename Handler,
  32     typename IoExecutor = system_executor, typename HandlerExecutor
  33       = typename associated_executor<Handler, IoExecutor>::type>
  34 class handler_work
  35 {
  36 public:
  37   explicit handler_work(Handler& handler) BOOST_ASIO_NOEXCEPT
  38     : io_executor_(),
  39       executor_(boost::asio::get_associated_executor(handler, io_executor_))
  40   {
  41   }
  42
  43   handler_work(Handler& handler, const IoExecutor& io_ex) BOOST_ASIO_NOEXCEPT
  44     : io_executor_(io_ex),
  45       executor_(boost::asio::get_associated_executor(handler, io_executor_))
  46   {
  47   }
  48
  49   static void start(Handler& handler) BOOST_ASIO_NOEXCEPT
  50   {
  51     HandlerExecutor ex(boost::asio::get_associated_executor(handler));
  52     ex.on_work_started();
  53   }
  54
  55   static void start(Handler& handler,
  56       const IoExecutor& io_ex) BOOST_ASIO_NOEXCEPT
  57   {
  58     HandlerExecutor ex(boost::asio::get_associated_executor(handler, io_ex));
  59     ex.on_work_started();
  60     io_ex.on_work_started();
  61   }
  62
  63   ~handler_work()
  64   {
  65     io_executor_.on_work_finished();
  66     executor_.on_work_finished();
  67   }
  68
  69   template <typename Function>
  70   void complete(Function& function, Handler& handler)
  71   {
  72     executor_.dispatch(BOOST_ASIO_MOVE_CAST(Function)(function),
  73         boost::asio::get_associated_allocator(handler));
  74   }
  75
  76 private:
  77   // Disallow copying and assignment.
  78   handler_work(const handler_work&);
  79   handler_work& operator=(const handler_work&);
  80
  81   IoExecutor io_executor_;
  82   HandlerExecutor executor_;
  83 };
  84
  85 // This specialisation dispatches a handler through the old invocation hook.
  86 // The specialisation is not strictly required for correctness, as the
  87 // system_executor will dispatch through the hook anyway. However, by doing
  88 // this we avoid an extra copy of the handler.
  89 template <typename Handler>
  90 class handler_work<Handler, system_executor, system_executor>
  91 {
  92 public:
  93   explicit handler_work(Handler&) BOOST_ASIO_NOEXCEPT {}
  94   static void start(Handler&) BOOST_ASIO_NOEXCEPT {}
  95   ~handler_work() {}
  96
  97   template <typename Function>
  98   void complete(Function& function, Handler& handler)
  99   {
 100     boost_asio_handler_invoke_helpers::invoke(function, handler);
 101   }
 102
 103 private:
 104   // Disallow copying and assignment.
 105   handler_work(const handler_work&);
 106   handler_work& operator=(const handler_work&);
 107 };
 108
 109 } // namespace detail
 110 } // namespace asio
 111 } // namespace boost
 112
 113 #include <boost/asio/detail/pop_options.hpp>
 114
 115 #endif // BOOST_ASIO_DETAIL_HANDLER_WORK_HPP