ceph/src/boost/boost/asio/system_executor.hpp

   1 //
   2 // system_executor.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_SYSTEM_EXECUTOR_HPP
  12 #define BOOST_ASIO_SYSTEM_EXECUTOR_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
  20 #include <boost/asio/detail/push_options.hpp>
  21
  22 namespace boost {
  23 namespace asio {
  24
  25 class system_context;
  26
  27 /// An executor that uses arbitrary threads.
  28 /**
  29  * The system executor represents an execution context where functions are
  30  * permitted to run on arbitrary threads. The post() and defer() functions
  31  * schedule the function to run on an unspecified system thread pool, and
  32  * dispatch() invokes the function immediately.
  33  */
  34 class system_executor
  35 {
  36 public:
  37   /// Obtain the underlying execution context.
  38   system_context& context() const BOOST_ASIO_NOEXCEPT;
  39
  40   /// Inform the executor that it has some outstanding work to do.
  41   /**
  42    * For the system executor, this is a no-op.
  43    */
  44   void on_work_started() const BOOST_ASIO_NOEXCEPT
  45   {
  46   }
  47
  48   /// Inform the executor that some work is no longer outstanding.
  49   /**
  50    * For the system executor, this is a no-op.
  51    */
  52   void on_work_finished() const BOOST_ASIO_NOEXCEPT
  53   {
  54   }
  55
  56   /// Request the system executor to invoke the given function object.
  57   /**
  58    * This function is used to ask the executor to execute the given function
  59    * object. The function object will always be executed inside this function.
  60    *
  61    * @param f The function object to be called. The executor will make
  62    * a copy of the handler object as required. The function signature of the
  63    * function object must be: @code void function(); @endcode
  64    *
  65    * @param a An allocator that may be used by the executor to allocate the
  66    * internal storage needed for function invocation.
  67    */
  68   template <typename Function, typename Allocator>
  69   void dispatch(BOOST_ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
  70
  71   /// Request the system executor to invoke the given function object.
  72   /**
  73    * This function is used to ask the executor to execute the given function
  74    * object. The function object will never be executed inside this function.
  75    * Instead, it will be scheduled to run on an unspecified system thread pool.
  76    *
  77    * @param f The function object to be called. The executor will make
  78    * a copy of the handler object as required. The function signature of the
  79    * function object must be: @code void function(); @endcode
  80    *
  81    * @param a An allocator that may be used by the executor to allocate the
  82    * internal storage needed for function invocation.
  83    */
  84   template <typename Function, typename Allocator>
  85   void post(BOOST_ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
  86
  87   /// Request the system executor to invoke the given function object.
  88   /**
  89    * This function is used to ask the executor to execute the given function
  90    * object. The function object will never be executed inside this function.
  91    * Instead, it will be scheduled to run on an unspecified system thread pool.
  92    *
  93    * @param f The function object to be called. The executor will make
  94    * a copy of the handler object as required. The function signature of the
  95    * function object must be: @code void function(); @endcode
  96    *
  97    * @param a An allocator that may be used by the executor to allocate the
  98    * internal storage needed for function invocation.
  99    */
 100   template <typename Function, typename Allocator>
 101   void defer(BOOST_ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
 102
 103   /// Compare two executors for equality.
 104   /**
 105    * System executors always compare equal.
 106    */
 107   friend bool operator==(const system_executor&,
 108       const system_executor&) BOOST_ASIO_NOEXCEPT
 109   {
 110     return true;
 111   }
 112
 113   /// Compare two executors for inequality.
 114   /**
 115    * System executors always compare equal.
 116    */
 117   friend bool operator!=(const system_executor&,
 118       const system_executor&) BOOST_ASIO_NOEXCEPT
 119   {
 120     return false;
 121   }
 122 };
 123
 124 } // namespace asio
 125 } // namespace boost
 126
 127 #include <boost/asio/detail/pop_options.hpp>
 128
 129 #include <boost/asio/impl/system_executor.hpp>
 130
 131 #endif // BOOST_ASIO_SYSTEM_EXECUTOR_HPP