130 lines
4.2 KiB
C++
130 lines
4.2 KiB
C++
//
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// system_executor.hpp
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// ~~~~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef ASIO_SYSTEM_EXECUTOR_HPP
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#define ASIO_SYSTEM_EXECUTOR_HPP
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#if defined(_MSC_VER) && (_MSC_VER >= 1200)
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# pragma once
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#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
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#include "asio/detail/config.hpp"
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#include "asio/detail/push_options.hpp"
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namespace asio {
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class system_context;
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/// An executor that uses arbitrary threads.
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/**
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* The system executor represents an execution context where functions are
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* permitted to run on arbitrary threads. The post() and defer() functions
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* schedule the function to run on an unspecified system thread pool, and
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* dispatch() invokes the function immediately.
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*/
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class system_executor
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{
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public:
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/// Obtain the underlying execution context.
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system_context& context() const ASIO_NOEXCEPT;
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/// Inform the executor that it has some outstanding work to do.
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/**
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* For the system executor, this is a no-op.
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*/
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void on_work_started() const ASIO_NOEXCEPT
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{
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}
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/// Inform the executor that some work is no longer outstanding.
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/**
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* For the system executor, this is a no-op.
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*/
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void on_work_finished() const ASIO_NOEXCEPT
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{
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}
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/// Request the system executor to invoke the given function object.
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/**
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* This function is used to ask the executor to execute the given function
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* object. The function object will always be executed inside this function.
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*
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* @param f The function object to be called. The executor will make
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* a copy of the handler object as required. The function signature of the
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* function object must be: @code void function(); @endcode
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*
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* @param a An allocator that may be used by the executor to allocate the
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* internal storage needed for function invocation.
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*/
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template <typename Function, typename Allocator>
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void dispatch(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
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/// Request the system executor to invoke the given function object.
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/**
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* This function is used to ask the executor to execute the given function
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* object. The function object will never be executed inside this function.
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* Instead, it will be scheduled to run on an unspecified system thread pool.
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*
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* @param f The function object to be called. The executor will make
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* a copy of the handler object as required. The function signature of the
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* function object must be: @code void function(); @endcode
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*
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* @param a An allocator that may be used by the executor to allocate the
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* internal storage needed for function invocation.
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*/
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template <typename Function, typename Allocator>
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void post(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
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/// Request the system executor to invoke the given function object.
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/**
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* This function is used to ask the executor to execute the given function
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* object. The function object will never be executed inside this function.
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* Instead, it will be scheduled to run on an unspecified system thread pool.
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*
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* @param f The function object to be called. The executor will make
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* a copy of the handler object as required. The function signature of the
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* function object must be: @code void function(); @endcode
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*
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* @param a An allocator that may be used by the executor to allocate the
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* internal storage needed for function invocation.
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*/
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template <typename Function, typename Allocator>
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void defer(ASIO_MOVE_ARG(Function) f, const Allocator& a) const;
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/// Compare two executors for equality.
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/**
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* System executors always compare equal.
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*/
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friend bool operator==(const system_executor&,
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const system_executor&) ASIO_NOEXCEPT
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{
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return true;
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}
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/// Compare two executors for inequality.
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/**
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* System executors always compare equal.
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*/
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friend bool operator!=(const system_executor&,
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const system_executor&) ASIO_NOEXCEPT
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{
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return false;
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}
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};
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} // namespace asio
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#include "asio/detail/pop_options.hpp"
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#include "asio/impl/system_executor.hpp"
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#endif // ASIO_SYSTEM_EXECUTOR_HPP
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