| // |
| // detail/strand_service.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_DETAIL_STRAND_SERVICE_HPP |
| #define ASIO_DETAIL_STRAND_SERVICE_HPP |
| |
| #if defined(_MSC_VER) && (_MSC_VER >= 1200) |
| # pragma once |
| #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) |
| |
| #include "asio/detail/config.hpp" |
| #include "asio/io_context.hpp" |
| #include "asio/detail/mutex.hpp" |
| #include "asio/detail/op_queue.hpp" |
| #include "asio/detail/operation.hpp" |
| #include "asio/detail/scoped_ptr.hpp" |
| |
| #include "asio/detail/push_options.hpp" |
| |
| namespace asio { |
| namespace detail { |
| |
| // Default service implementation for a strand. |
| class strand_service |
| : public asio::detail::service_base<strand_service> |
| { |
| private: |
| // Helper class to re-post the strand on exit. |
| struct on_do_complete_exit; |
| |
| // Helper class to re-post the strand on exit. |
| struct on_dispatch_exit; |
| |
| public: |
| |
| // The underlying implementation of a strand. |
| class strand_impl |
| : public operation |
| { |
| public: |
| strand_impl(); |
| |
| private: |
| // Only this service will have access to the internal values. |
| friend class strand_service; |
| friend struct on_do_complete_exit; |
| friend struct on_dispatch_exit; |
| |
| // Mutex to protect access to internal data. |
| asio::detail::mutex mutex_; |
| |
| // Indicates whether the strand is currently "locked" by a handler. This |
| // means that there is a handler upcall in progress, or that the strand |
| // itself has been scheduled in order to invoke some pending handlers. |
| bool locked_; |
| |
| // The handlers that are waiting on the strand but should not be run until |
| // after the next time the strand is scheduled. This queue must only be |
| // modified while the mutex is locked. |
| op_queue<operation> waiting_queue_; |
| |
| // The handlers that are ready to be run. Logically speaking, these are the |
| // handlers that hold the strand's lock. The ready queue is only modified |
| // from within the strand and so may be accessed without locking the mutex. |
| op_queue<operation> ready_queue_; |
| }; |
| |
| typedef strand_impl* implementation_type; |
| |
| // Construct a new strand service for the specified io_context. |
| ASIO_DECL explicit strand_service(asio::io_context& io_context); |
| |
| // Destroy all user-defined handler objects owned by the service. |
| ASIO_DECL void shutdown(); |
| |
| // Construct a new strand implementation. |
| ASIO_DECL void construct(implementation_type& impl); |
| |
| // Request the io_context to invoke the given handler. |
| template <typename Handler> |
| void dispatch(implementation_type& impl, Handler& handler); |
| |
| // Request the io_context to invoke the given handler and return immediately. |
| template <typename Handler> |
| void post(implementation_type& impl, Handler& handler); |
| |
| // Determine whether the strand is running in the current thread. |
| ASIO_DECL bool running_in_this_thread( |
| const implementation_type& impl) const; |
| |
| private: |
| // Helper function to dispatch a handler. Returns true if the handler should |
| // be dispatched immediately. |
| ASIO_DECL bool do_dispatch(implementation_type& impl, operation* op); |
| |
| // Helper fiunction to post a handler. |
| ASIO_DECL void do_post(implementation_type& impl, |
| operation* op, bool is_continuation); |
| |
| ASIO_DECL static void do_complete(void* owner, |
| operation* base, const asio::error_code& ec, |
| std::size_t bytes_transferred); |
| |
| // The io_context implementation used to post completions. |
| io_context_impl& io_context_; |
| |
| // Mutex to protect access to the array of implementations. |
| asio::detail::mutex mutex_; |
| |
| // Number of implementations shared between all strand objects. |
| #if defined(ASIO_STRAND_IMPLEMENTATIONS) |
| enum { num_implementations = ASIO_STRAND_IMPLEMENTATIONS }; |
| #else // defined(ASIO_STRAND_IMPLEMENTATIONS) |
| enum { num_implementations = 193 }; |
| #endif // defined(ASIO_STRAND_IMPLEMENTATIONS) |
| |
| // Pool of implementations. |
| scoped_ptr<strand_impl> implementations_[num_implementations]; |
| |
| // Extra value used when hashing to prevent recycled memory locations from |
| // getting the same strand implementation. |
| std::size_t salt_; |
| }; |
| |
| } // namespace detail |
| } // namespace asio |
| |
| #include "asio/detail/pop_options.hpp" |
| |
| #include "asio/detail/impl/strand_service.hpp" |
| #if defined(ASIO_HEADER_ONLY) |
| # include "asio/detail/impl/strand_service.ipp" |
| #endif // defined(ASIO_HEADER_ONLY) |
| |
| #endif // ASIO_DETAIL_STRAND_SERVICE_HPP |