ceph/src/boost/boost/asio/executor_work_guard.hpp

   1 //
   2 // executor_work_guard.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_EXECUTOR_WORK_GUARD_HPP
  12 #define BOOST_ASIO_EXECUTOR_WORK_GUARD_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/type_traits.hpp>
  21 #include <boost/asio/is_executor.hpp>
  22
  23 #include <boost/asio/detail/push_options.hpp>
  24
  25 namespace boost {
  26 namespace asio {
  27
  28 /// An object of type @c executor_work_guard controls ownership of executor work
  29 /// within a scope.
  30 template <typename Executor>
  31 class executor_work_guard
  32 {
  33 public:
  34   /// The underlying executor type.
  35   typedef Executor executor_type;
  36
  37   /// Constructs a @c executor_work_guard object for the specified executor.
  38   /**
  39    * Stores a copy of @c e and calls <tt>on_work_started()</tt> on it.
  40    */
  41   explicit executor_work_guard(const executor_type& e) BOOST_ASIO_NOEXCEPT
  42     : executor_(e),
  43       owns_(true)
  44   {
  45     executor_.on_work_started();
  46   }
  47
  48   /// Copy constructor.
  49   executor_work_guard(const executor_work_guard& other) BOOST_ASIO_NOEXCEPT
  50     : executor_(other.executor_),
  51       owns_(other.owns_)
  52   {
  53     if (owns_)
  54       executor_.on_work_started();
  55   }
  56
  57 #if defined(BOOST_ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
  58   /// Move constructor.
  59   executor_work_guard(executor_work_guard&& other) BOOST_ASIO_NOEXCEPT
  60     : executor_(BOOST_ASIO_MOVE_CAST(Executor)(other.executor_)),
  61       owns_(other.owns_)
  62   {
  63     other.owns_ = false;
  64   }
  65 #endif //  defined(BOOST_ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
  66
  67   /// Destructor.
  68   /**
  69    * Unless the object has already been reset, or is in a moved-from state,
  70    * calls <tt>on_work_finished()</tt> on the stored executor.
  71    */
  72   ~executor_work_guard()
  73   {
  74     if (owns_)
  75       executor_.on_work_finished();
  76   }
  77
  78   /// Obtain the associated executor.
  79   executor_type get_executor() const BOOST_ASIO_NOEXCEPT
  80   {
  81     return executor_;
  82   }
  83
  84   /// Whether the executor_work_guard object owns some outstanding work.
  85   bool owns_work() const BOOST_ASIO_NOEXCEPT
  86   {
  87     return owns_;
  88   }
  89
  90   /// Indicate that the work is no longer outstanding.
  91   /**
  92    * Unless the object has already been reset, or is in a moved-from state,
  93    * calls <tt>on_work_finished()</tt> on the stored executor.
  94    */
  95   void reset() BOOST_ASIO_NOEXCEPT
  96   {
  97     if (owns_)
  98     {
  99       executor_.on_work_finished();
 100       owns_ = false;
 101     }
 102   }
 103
 104 private:
 105   // Disallow assignment.
 106   executor_work_guard& operator=(const executor_work_guard&);
 107
 108   executor_type executor_;
 109   bool owns_;
 110 };
 111
 112 /// Create an @ref executor_work_guard object.
 113 template <typename Executor>
 114 inline executor_work_guard<Executor> make_work_guard(const Executor& ex,
 115     typename enable_if<is_executor<Executor>::value>::type* = 0)
 116 {
 117   return executor_work_guard<Executor>(ex);
 118 }
 119
 120 /// Create an @ref executor_work_guard object.
 121 template <typename ExecutionContext>
 122 inline executor_work_guard<typename ExecutionContext::executor_type>
 123 make_work_guard(ExecutionContext& ctx,
 124     typename enable_if<
 125       is_convertible<ExecutionContext&, execution_context&>::value>::type* = 0)
 126 {
 127   return executor_work_guard<typename ExecutionContext::executor_type>(
 128       ctx.get_executor());
 129 }
 130
 131 /// Create an @ref executor_work_guard object.
 132 template <typename T>
 133 inline executor_work_guard<typename associated_executor<T>::type>
 134 make_work_guard(const T& t,
 135     typename enable_if<!is_executor<T>::value &&
 136       !is_convertible<T&, execution_context&>::value>::type* = 0)
 137 {
 138   return executor_work_guard<typename associated_executor<T>::type>(
 139       associated_executor<T>::get(t));
 140 }
 141
 142 /// Create an @ref executor_work_guard object.
 143 template <typename T, typename Executor>
 144 inline executor_work_guard<typename associated_executor<T, Executor>::type>
 145 make_work_guard(const T& t, const Executor& ex,
 146     typename enable_if<is_executor<Executor>::value>::type* = 0)
 147 {
 148   return executor_work_guard<typename associated_executor<T, Executor>::type>(
 149       associated_executor<T, Executor>::get(t, ex));
 150 }
 151
 152 /// Create an @ref executor_work_guard object.
 153 template <typename T, typename ExecutionContext>
 154 inline executor_work_guard<typename associated_executor<T,
 155   typename ExecutionContext::executor_type>::type>
 156 make_work_guard(const T& t, ExecutionContext& ctx,
 157     typename enable_if<!is_executor<T>::value &&
 158       !is_convertible<T&, execution_context&>::value &&
 159       is_convertible<ExecutionContext&, execution_context&>::value>::type* = 0)
 160 {
 161   return executor_work_guard<typename associated_executor<T,
 162     typename ExecutionContext::executor_type>::type>(
 163       associated_executor<T, typename ExecutionContext::executor_type>::get(
 164         t, ctx.get_executor()));
 165 }
 166
 167 } // namespace asio
 168 } // namespace boost
 169
 170 #include <boost/asio/detail/pop_options.hpp>
 171
 172 #endif // BOOST_ASIO_EXECUTOR_WORK_GUARD_HPP