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Diffstat (limited to 'lib/asio/strand.hpp')
-rw-r--r-- | lib/asio/strand.hpp | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/lib/asio/strand.hpp b/lib/asio/strand.hpp new file mode 100644 index 0000000..ea78ef0 --- /dev/null +++ b/lib/asio/strand.hpp @@ -0,0 +1,286 @@ +// +// strand.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_STRAND_HPP +#define ASIO_STRAND_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/strand_executor_service.hpp" +#include "asio/detail/type_traits.hpp" + +#include "asio/detail/push_options.hpp" + +namespace asio { + +/// Provides serialised function invocation for any executor type. +template <typename Executor> +class strand +{ +public: + /// The type of the underlying executor. + typedef Executor inner_executor_type; + + /// Default constructor. + /** + * This constructor is only valid if the underlying executor type is default + * constructible. + */ + strand() + : executor_(), + impl_(use_service<detail::strand_executor_service>( + executor_.context()).create_implementation()) + { + } + + /// Construct a strand for the specified executor. + explicit strand(const Executor& e) + : executor_(e), + impl_(use_service<detail::strand_executor_service>( + executor_.context()).create_implementation()) + { + } + + /// Copy constructor. + strand(const strand& other) ASIO_NOEXCEPT + : executor_(other.executor_), + impl_(other.impl_) + { + } + + /// Converting constructor. + /** + * This constructor is only valid if the @c OtherExecutor type is convertible + * to @c Executor. + */ + template <class OtherExecutor> + strand( + const strand<OtherExecutor>& other) ASIO_NOEXCEPT + : executor_(other.executor_), + impl_(other.impl_) + { + } + + /// Assignment operator. + strand& operator=(const strand& other) ASIO_NOEXCEPT + { + executor_ = other.executor_; + impl_ = other.impl_; + return *this; + } + + /// Converting assignment operator. + /** + * This assignment operator is only valid if the @c OtherExecutor type is + * convertible to @c Executor. + */ + template <class OtherExecutor> + strand& operator=( + const strand<OtherExecutor>& other) ASIO_NOEXCEPT + { + executor_ = other.executor_; + impl_ = other.impl_; + return *this; + } + +#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION) + /// Move constructor. + strand(strand&& other) ASIO_NOEXCEPT + : executor_(ASIO_MOVE_CAST(Executor)(other.executor_)), + impl_(ASIO_MOVE_CAST(implementation_type)(other.impl_)) + { + } + + /// Converting move constructor. + /** + * This constructor is only valid if the @c OtherExecutor type is convertible + * to @c Executor. + */ + template <class OtherExecutor> + strand(strand<OtherExecutor>&& other) ASIO_NOEXCEPT + : executor_(ASIO_MOVE_CAST(OtherExecutor)(other)), + impl_(ASIO_MOVE_CAST(implementation_type)(other.impl_)) + { + } + + /// Move assignment operator. + strand& operator=(strand&& other) ASIO_NOEXCEPT + { + executor_ = ASIO_MOVE_CAST(Executor)(other); + impl_ = ASIO_MOVE_CAST(implementation_type)(other.impl_); + return *this; + } + + /// Converting move assignment operator. + /** + * This assignment operator is only valid if the @c OtherExecutor type is + * convertible to @c Executor. + */ + template <class OtherExecutor> + strand& operator=( + const strand<OtherExecutor>&& other) ASIO_NOEXCEPT + { + executor_ = ASIO_MOVE_CAST(OtherExecutor)(other); + impl_ = ASIO_MOVE_CAST(implementation_type)(other.impl_); + return *this; + } +#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION) + + /// Destructor. + ~strand() + { + } + + /// Obtain the underlying executor. + inner_executor_type get_inner_executor() const ASIO_NOEXCEPT + { + return executor_; + } + + /// Obtain the underlying execution context. + execution_context& context() const ASIO_NOEXCEPT + { + return executor_.context(); + } + + /// Inform the strand that it has some outstanding work to do. + /** + * The strand delegates this call to its underlying executor. + */ + void on_work_started() const ASIO_NOEXCEPT + { + executor_.on_work_started(); + } + + /// Inform the strand that some work is no longer outstanding. + /** + * The strand delegates this call to its underlying executor. + */ + void on_work_finished() const ASIO_NOEXCEPT + { + executor_.on_work_finished(); + } + + /// Request the strand to invoke the given function object. + /** + * This function is used to ask the strand to execute the given function + * object on its underlying executor. The function object will be executed + * inside this function if the strand is not otherwise busy and if the + * underlying executor's @c dispatch() function is also able to execute the + * function before returning. + * + * @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 + { + detail::strand_executor_service::dispatch(impl_, + executor_, ASIO_MOVE_CAST(Function)(f), a); + } + + /// Request the strand 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 by the underlying executor's defer 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 post(ASIO_MOVE_ARG(Function) f, const Allocator& a) const + { + detail::strand_executor_service::post(impl_, + executor_, ASIO_MOVE_CAST(Function)(f), a); + } + + /// Request the strand 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 by the underlying executor's defer 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 defer(ASIO_MOVE_ARG(Function) f, const Allocator& a) const + { + detail::strand_executor_service::defer(impl_, + executor_, ASIO_MOVE_CAST(Function)(f), a); + } + + /// Determine whether the strand is running in the current thread. + /** + * @return @c true if the current thread is executing a function that was + * submitted to the strand using post(), dispatch() or defer(). Otherwise + * returns @c false. + */ + bool running_in_this_thread() const ASIO_NOEXCEPT + { + return detail::strand_executor_service::running_in_this_thread(impl_); + } + + /// Compare two strands for equality. + /** + * Two strands are equal if they refer to the same ordered, non-concurrent + * state. + */ + friend bool operator==(const strand& a, const strand& b) ASIO_NOEXCEPT + { + return a.impl_ == b.impl_; + } + + /// Compare two strands for inequality. + /** + * Two strands are equal if they refer to the same ordered, non-concurrent + * state. + */ + friend bool operator!=(const strand& a, const strand& b) ASIO_NOEXCEPT + { + return a.impl_ != b.impl_; + } + +private: + Executor executor_; + typedef detail::strand_executor_service::implementation_type + implementation_type; + implementation_type impl_; +}; + +} // namespace asio + +#include "asio/detail/pop_options.hpp" + +// If both io_context.hpp and strand.hpp have been included, automatically +// include the header file needed for the io_context::strand class. +#if !defined(ASIO_NO_EXTENSIONS) +# if defined(ASIO_IO_CONTEXT_HPP) +# include "asio/io_context_strand.hpp" +# endif // defined(ASIO_IO_CONTEXT_HPP) +#endif // !defined(ASIO_NO_EXTENSIONS) + +#endif // ASIO_STRAND_HPP |