| // |
| // system_executor.hpp |
| // ~~~~~~~~~~~~~~~~~~~ |
| // |
| // Copyright (c) 2003-2016 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_SYSTEM_EXECUTOR_HPP |
| #define ASIO_SYSTEM_EXECUTOR_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/scheduler.hpp" |
| #include "asio/detail/thread_group.hpp" |
| #include "asio/execution_context.hpp" |
| |
| #include "asio/detail/push_options.hpp" |
| |
| namespace asio { |
| |
| /// An executor that uses arbitrary threads. |
| /** |
| * The system executor represents an execution context where functions are |
| * permitted to run on arbitrary threads. The post() and defer() functions |
| * schedule the function to run on an unspecified system thread pool, and |
| * dispatch() invokes the function immediately. |
| */ |
| class system_executor |
| { |
| public: |
| /// Obtain the underlying execution context. |
| execution_context& context() const ASIO_NOEXCEPT; |
| |
| /// Inform the executor that it has some outstanding work to do. |
| /** |
| * For the system executor, this is a no-op. |
| */ |
| void on_work_started() const ASIO_NOEXCEPT |
| { |
| } |
| |
| /// Inform the executor that some work is no longer outstanding. |
| /** |
| * For the system executor, this is a no-op. |
| */ |
| void on_work_finished() const ASIO_NOEXCEPT |
| { |
| } |
| |
| /// Request the system executor to invoke the given function object. |
| /** |
| * This function is used to ask the executor to execute the given function |
| * object. The function object will always be executed inside this function. |
| * |
| * @param f The function object to be called. The executor will make |
| * a copy of the handler object as required. The function signature of the |
| * function object must be: @code void function(); @endcode |
| * |
| * @param a An allocator that may be used by the executor to allocate the |
| * internal storage needed for function invocation. |
| */ |
| template <typename Function, typename Allocator> |
| void dispatch(ASIO_MOVE_ARG(Function) f, const Allocator& a) const; |
| |
| /// Request the system executor to invoke the given function object. |
| /** |
| * This function is used to ask the executor to execute the given function |
| * object. The function object will never be executed inside this function. |
| * Instead, it will be scheduled to run on an unspecified system thread pool. |
| * |
| * @param f The function object to be called. The executor will make |
| * a copy of the handler object as required. The function signature of the |
| * function object must be: @code void function(); @endcode |
| * |
| * @param a An allocator that may be used by the executor to allocate the |
| * internal storage needed for function invocation. |
| */ |
| template <typename Function, typename Allocator> |
| void post(ASIO_MOVE_ARG(Function) f, const Allocator& a) const; |
| |
| /// Request the system executor to invoke the given function object. |
| /** |
| * This function is used to ask the executor to execute the given function |
| * object. The function object will never be executed inside this function. |
| * Instead, it will be scheduled to run on an unspecified system thread pool. |
| * |
| * @param f The function object to be called. The executor will make |
| * a copy of the handler object as required. The function signature of the |
| * function object must be: @code void function(); @endcode |
| * |
| * @param a An allocator that may be used by the executor to allocate the |
| * internal storage needed for function invocation. |
| */ |
| template <typename Function, typename Allocator> |
| void defer(ASIO_MOVE_ARG(Function) f, const Allocator& a) const; |
| |
| /// Compare two executors for equality. |
| /** |
| * System executors always compare equal. |
| */ |
| friend bool operator==(const system_executor&, |
| const system_executor&) ASIO_NOEXCEPT |
| { |
| return true; |
| } |
| |
| /// Compare two executors for inequality. |
| /** |
| * System executors always compare equal. |
| */ |
| friend bool operator!=(const system_executor&, |
| const system_executor&) ASIO_NOEXCEPT |
| { |
| return false; |
| } |
| |
| private: |
| struct thread_function; |
| |
| // Hidden implementation of the system execution context. |
| struct context_impl |
| : public execution_context |
| { |
| // Constructor creates all threads in the system thread pool. |
| ASIO_DECL context_impl(); |
| |
| // Destructor shuts down all threads in the system thread pool. |
| ASIO_DECL ~context_impl(); |
| |
| // The underlying scheduler. |
| detail::scheduler& scheduler_; |
| |
| // The threads in the system thread pool. |
| detail::thread_group threads_; |
| }; |
| }; |
| |
| } // namespace asio |
| |
| #include "asio/detail/pop_options.hpp" |
| |
| #include "asio/impl/system_executor.hpp" |
| #if defined(ASIO_HEADER_ONLY) |
| # include "asio/impl/system_executor.ipp" |
| #endif // defined(ASIO_HEADER_ONLY) |
| |
| #endif // ASIO_SYSTEM_EXECUTOR_HPP |