| // |
| // detail/strand_executor_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_EXECUTOR_SERVICE_HPP |
| #define ASIO_DETAIL_STRAND_EXECUTOR_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/detail/atomic_count.hpp" |
| #include "asio/detail/executor_op.hpp" |
| #include "asio/detail/memory.hpp" |
| #include "asio/detail/mutex.hpp" |
| #include "asio/detail/op_queue.hpp" |
| #include "asio/detail/scheduler_operation.hpp" |
| #include "asio/detail/scoped_ptr.hpp" |
| #include "asio/execution_context.hpp" |
| |
| #include "asio/detail/push_options.hpp" |
| |
| namespace asio { |
| namespace detail { |
| |
| // Default service implementation for a strand. |
| class strand_executor_service |
| : public execution_context_service_base<strand_executor_service> |
| { |
| public: |
| // The underlying implementation of a strand. |
| class strand_impl |
| { |
| public: |
| ASIO_DECL ~strand_impl(); |
| |
| private: |
| friend class strand_executor_service; |
| |
| // Mutex to protect access to internal data. |
| 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<scheduler_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<scheduler_operation> ready_queue_; |
| |
| // Pointers to adjacent handle implementations in linked list. |
| strand_impl* next_; |
| strand_impl* prev_; |
| |
| // The strand service in where the implementation is held. |
| strand_executor_service* service_; |
| }; |
| |
| typedef shared_ptr<strand_impl> implementation_type; |
| |
| // Construct a new strand service for the specified context. |
| ASIO_DECL explicit strand_executor_service(execution_context& context); |
| |
| // Destroy all user-defined handler objects owned by the service. |
| ASIO_DECL void shutdown(); |
| |
| // Create a new strand_executor implementation. |
| ASIO_DECL implementation_type create_implementation(); |
| |
| // Request invocation of the given function. |
| template <typename Executor, typename Function, typename Allocator> |
| static void dispatch(const implementation_type& impl, Executor& ex, |
| ASIO_MOVE_ARG(Function) function, const Allocator& a); |
| |
| // Request invocation of the given function and return immediately. |
| template <typename Executor, typename Function, typename Allocator> |
| static void post(const implementation_type& impl, Executor& ex, |
| ASIO_MOVE_ARG(Function) function, const Allocator& a); |
| |
| // Request invocation of the given function and return immediately. |
| template <typename Executor, typename Function, typename Allocator> |
| static void defer(const implementation_type& impl, Executor& ex, |
| ASIO_MOVE_ARG(Function) function, const Allocator& a); |
| |
| // Determine whether the strand is running in the current thread. |
| ASIO_DECL static bool running_in_this_thread( |
| const implementation_type& impl); |
| |
| private: |
| friend class strand_impl; |
| template <typename Executor> class invoker; |
| |
| // Adds a function to the strand. Returns true if it acquires the lock. |
| ASIO_DECL static bool enqueue(const implementation_type& impl, |
| scheduler_operation* op); |
| |
| // Mutex to protect access to the service-wide state. |
| mutex mutex_; |
| |
| // Number of mutexes shared between all strand objects. |
| enum { num_mutexes = 193 }; |
| |
| // Pool of mutexes. |
| scoped_ptr<mutex> mutexes_[num_mutexes]; |
| |
| // Extra value used when hashing to prevent recycled memory locations from |
| // getting the same mutex. |
| std::size_t salt_; |
| |
| // The head of a linked list of all implementations. |
| strand_impl* impl_list_; |
| }; |
| |
| } // namespace detail |
| } // namespace asio |
| |
| #include "asio/detail/pop_options.hpp" |
| |
| #include "asio/detail/impl/strand_executor_service.hpp" |
| #if defined(ASIO_HEADER_ONLY) |
| # include "asio/detail/impl/strand_executor_service.ipp" |
| #endif // defined(ASIO_HEADER_ONLY) |
| |
| #endif // ASIO_DETAIL_STRAND_EXECUTOR_SERVICE_HPP |