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Diffstat (limited to 'lib/asio/detail/strand_executor_service.hpp')
-rw-r--r-- | lib/asio/detail/strand_executor_service.hpp | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/lib/asio/detail/strand_executor_service.hpp b/lib/asio/detail/strand_executor_service.hpp new file mode 100644 index 0000000..67e8427 --- /dev/null +++ b/lib/asio/detail/strand_executor_service.hpp @@ -0,0 +1,142 @@ +// +// detail/strand_executor_service.hpp +// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +// +// Copyright (c) 2003-2018 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_; + + // Indicates that the strand has been shut down and will accept no further + // handlers. + bool shutdown_; + + // 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 |