added asio

include/asio/detail/work_dispatcher.hpp

@@ -0,0 +1,303 @@
+//
+// detail/work_dispatcher.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_DETAIL_WORK_DISPATCHER_HPP
+#define ASIO_DETAIL_WORK_DISPATCHER_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include "asio/detail/bind_handler.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/associated_executor.hpp"
+#include "asio/associated_allocator.hpp"
+#include "asio/executor_work_guard.hpp"
+#include "asio/execution/executor.hpp"
+#include "asio/execution/allocator.hpp"
+#include "asio/execution/blocking.hpp"
+#include "asio/execution/outstanding_work.hpp"
+#include "asio/prefer.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace detail {
+
+struct empty_work_function
+{
+  void operator()() const noexcept
+  {
+  }
+};
+
+template <typename Function>
+struct work_result
+{
+  typedef decay_t<result_of_t<decay_t<Function>()>> type;
+};
+
+template <typename Function>
+using work_result_t = typename work_result<Function>::type;
+
+template <typename Function, typename Handler,
+    typename Executor, typename = void>
+struct is_work_dispatcher_required : true_type
+{
+};
+
+template <typename Handler, typename Executor>
+struct is_work_dispatcher_required<empty_work_function, Handler, Executor,
+    enable_if_t<
+      is_same<
+        typename associated_executor<Handler,
+          Executor>::asio_associated_executor_is_unspecialised,
+        void
+      >::value
+    >> : false_type
+{
+};
+
+template <typename Function,
+    bool IsVoid = is_void<result_of_t<Function()>>::value,
+    bool IsClass = is_class<Function>::value>
+class work_dispatcher_function
+{
+  Function function_;
+
+public:
+  template <typename F>
+  work_dispatcher_function(F&& function)
+    : function_(static_cast<F&&>(function))
+  {
+  }
+
+  work_dispatcher_function(const work_dispatcher_function& other)
+    : function_(other.function_)
+  {
+  }
+
+  work_dispatcher_function(work_dispatcher_function&& other)
+    : function_(static_cast<Function&&>(other.function_))
+  {
+  }
+
+  template <typename Handler>
+  auto bind_result(Handler&& handler)
+    -> decltype(
+      asio::detail::move_bind_handler(
+        static_cast<Handler&&>(handler),
+        static_cast<Function&&>(function_)()))
+  {
+    return asio::detail::move_bind_handler(
+        static_cast<Handler&&>(handler),
+        static_cast<Function&&>(function_)());
+  }
+};
+
+template <typename Function>
+class work_dispatcher_function<Function, false, true> : Function
+{
+public:
+  template <typename F>
+  work_dispatcher_function(F&& function)
+    : Function(static_cast<F&&>(function))
+  {
+  }
+
+  work_dispatcher_function(const work_dispatcher_function& other)
+    : Function(static_cast<const Function&>(other))
+  {
+  }
+
+  work_dispatcher_function(work_dispatcher_function&& other)
+    : Function(static_cast<Function&&>(other))
+  {
+  }
+
+  template <typename Handler>
+  auto bind_result(Handler&& handler)
+    -> decltype(
+      asio::detail::move_bind_handler(
+        static_cast<Handler&&>(handler),
+        static_cast<Function&&>(*static_cast<Function*>(this))()))
+  {
+    return asio::detail::move_bind_handler(
+        static_cast<Handler&&>(handler),
+        static_cast<Function&&>(*static_cast<Function*>(this))());
+  }
+};
+
+template <typename Function>
+class work_dispatcher_function<Function, true, false>
+{
+  Function function_;
+
+public:
+  template <typename F>
+  work_dispatcher_function(F&& function)
+    : function_(static_cast<Function&&>(function))
+  {
+  }
+
+  work_dispatcher_function(const work_dispatcher_function& other)
+    : function_(other.function_)
+  {
+  }
+
+  work_dispatcher_function(work_dispatcher_function&& other)
+    : function_(static_cast<Function&&>(other.function_))
+  {
+  }
+
+  template <typename Handler>
+  auto bind_result(Handler&& handler)
+    -> decltype(asio::detail::bind_handler(
+      static_cast<Handler&&>(handler)))
+  {
+    static_cast<Function&&>(function_)();
+    return asio::detail::bind_handler(
+        static_cast<Handler&&>(handler));
+  }
+};
+
+template <typename Function>
+class work_dispatcher_function<Function, true, true> : Function
+{
+public:
+  template <typename F>
+  work_dispatcher_function(F&& function)
+    : Function(static_cast<F&&>(function))
+  {
+  }
+
+  work_dispatcher_function(const work_dispatcher_function& other)
+    : Function(static_cast<const Function&>(other))
+  {
+  }
+
+  work_dispatcher_function(work_dispatcher_function&& other)
+    : Function(static_cast<Function&&>(other))
+  {
+  }
+
+  template <typename Handler>
+  auto bind_result(Handler&& handler)
+    -> decltype(asio::detail::bind_handler(
+      static_cast<Handler&&>(handler)))
+  {
+    static_cast<Function&&>(*static_cast<Function*>(this))();
+    return asio::detail::bind_handler(
+        static_cast<Handler&&>(handler));
+  }
+};
+
+template <typename Function, typename Handler,
+    typename Executor, typename = void>
+class work_dispatcher : work_dispatcher_function<Function>
+{
+public:
+  template <typename F, typename CompletionHandler>
+  work_dispatcher(F&& function, CompletionHandler&& handler,
+      const Executor& handler_ex)
+    : work_dispatcher_function<Function>(static_cast<F&&>(function)),
+      handler_(static_cast<CompletionHandler&&>(handler)),
+      executor_(asio::prefer(handler_ex,
+          execution::outstanding_work.tracked))
+  {
+  }
+
+  work_dispatcher(const work_dispatcher& other)
+    : work_dispatcher_function<Function>(other),
+      handler_(other.handler_),
+      executor_(other.executor_)
+  {
+  }
+
+  work_dispatcher(work_dispatcher&& other)
+    : work_dispatcher_function<Function>(
+        static_cast<work_dispatcher_function<Function>&&>(other)),
+      handler_(static_cast<Handler&&>(other.handler_)),
+      executor_(static_cast<work_executor_type&&>(other.executor_))
+  {
+  }
+
+  void operator()()
+  {
+    associated_allocator_t<Handler> alloc((get_associated_allocator)(handler_));
+    asio::prefer(executor_, execution::allocator(alloc)).execute(
+        this->bind_result(static_cast<Handler&&>(handler_)));
+  }
+
+private:
+  typedef decay_t<
+      prefer_result_t<const Executor&,
+        execution::outstanding_work_t::tracked_t
+      >
+    > work_executor_type;
+
+  Handler handler_;
+  work_executor_type executor_;
+};
+
+#if !defined(ASIO_NO_TS_EXECUTORS)
+
+template <typename Function, typename Handler, typename Executor>
+class work_dispatcher<Function, Handler, Executor,
+    enable_if_t<!execution::is_executor<Executor>::value>>
+  : work_dispatcher_function<Function>
+{
+public:
+  template <typename F, typename CompletionHandler>
+  work_dispatcher(F&& function, CompletionHandler&& handler,
+      const Executor& handler_ex)
+    : work_dispatcher_function<Function>(static_cast<F&&>(function)),
+      work_(handler_ex),
+      handler_(static_cast<CompletionHandler&&>(handler))
+  {
+  }
+
+  work_dispatcher(const work_dispatcher& other)
+    : work_dispatcher_function<Function>(other),
+      work_(other.work_),
+      handler_(other.handler_)
+  {
+  }
+
+  work_dispatcher(work_dispatcher&& other)
+    : work_dispatcher_function<Function>(
+        static_cast<work_dispatcher_function<Function>&&>(*this)),
+      work_(static_cast<executor_work_guard<Executor>&&>(other.work_)),
+      handler_(static_cast<Handler&&>(other.handler_))
+  {
+  }
+
+  void operator()()
+  {
+    associated_allocator_t<Handler> alloc((get_associated_allocator)(handler_));
+    work_.get_executor().dispatch(
+        this->bind_result(static_cast<Handler&&>(handler_)), alloc);
+    work_.reset();
+  }
+
+private:
+  executor_work_guard<Executor> work_;
+  Handler handler_;
+};
+
+#endif // !defined(ASIO_NO_TS_EXECUTORS)
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_WORK_DISPATCHER_HPP