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

   1 //
   2 // detail/handler_work.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2017 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, typename Executor
  32     = typename associated_executor<Handler>::type>
  33 class handler_work
  34 {
  35 public:
  36   explicit handler_work(Handler& handler) BOOST_ASIO_NOEXCEPT
  37     : executor_(associated_executor<Handler>::get(handler))
  38   {
  39   }
  40
  41   static void start(Handler& handler) BOOST_ASIO_NOEXCEPT
  42   {
  43     Executor ex(associated_executor<Handler>::get(handler));
  44     ex.on_work_started();
  45   }
  46
  47   ~handler_work()
  48   {
  49     executor_.on_work_finished();
  50   }
  51
  52   template <typename Function>
  53   void complete(Function& function, Handler& handler)
  54   {
  55     executor_.dispatch(BOOST_ASIO_MOVE_CAST(Function)(function),
  56         associated_allocator<Handler>::get(handler));
  57   }
  58
  59 private:
  60   // Disallow copying and assignment.
  61   handler_work(const handler_work&);
  62   handler_work& operator=(const handler_work&);
  63
  64   typename associated_executor<Handler>::type executor_;
  65 };
  66
  67 // This specialisation dispatches a handler through the old invocation hook.
  68 // The specialisation is not strictly required for correctness, as the
  69 // system_executor will dispatch through the hook anyway. However, by doing
  70 // this we avoid an extra copy of the handler.
  71 template <typename Handler>
  72 class handler_work<Handler, system_executor>
  73 {
  74 public:
  75   explicit handler_work(Handler&) BOOST_ASIO_NOEXCEPT {}
  76   static void start(Handler&) BOOST_ASIO_NOEXCEPT {}
  77   ~handler_work() {}
  78
  79   template <typename Function>
  80   void complete(Function& function, Handler& handler)
  81   {
  82     boost_asio_handler_invoke_helpers::invoke(function, handler);
  83   }
  84
  85 private:
  86   // Disallow copying and assignment.
  87   handler_work(const handler_work&);
  88   handler_work& operator=(const handler_work&);
  89 };
  90
  91 } // namespace detail
  92 } // namespace asio
  93 } // namespace boost
  94
  95 #include <boost/asio/detail/pop_options.hpp>
  96
  97 #endif // BOOST_ASIO_DETAIL_HANDLER_WORK_HPP