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Diffstat (limited to '3rdparty/asio/include/asio/strand.hpp')
-rw-r--r-- | 3rdparty/asio/include/asio/strand.hpp | 569 |
1 files changed, 569 insertions, 0 deletions
diff --git a/3rdparty/asio/include/asio/strand.hpp b/3rdparty/asio/include/asio/strand.hpp new file mode 100644 index 00000000000..52b2314df56 --- /dev/null +++ b/3rdparty/asio/include/asio/strand.hpp @@ -0,0 +1,569 @@ +// +// strand.hpp +// ~~~~~~~~~~ +// +// Copyright (c) 2003-2021 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/execution/blocking.hpp" +#include "asio/execution/executor.hpp" +#include "asio/is_executor.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_(strand::create_implementation(executor_)) + { + } + + /// Construct a strand for the specified executor. + template <typename Executor1> + explicit strand(const Executor1& e, + typename constraint< + conditional< + !is_same<Executor1, strand>::value, + is_convertible<Executor1, Executor>, + false_type + >::type::value + >::type = 0) + : executor_(e), + impl_(strand::create_implementation(executor_)) + { + } + + /// 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.executor_)), + impl_(ASIO_MOVE_CAST(implementation_type)(other.impl_)) + { + } + + /// Move assignment operator. + strand& operator=(strand&& other) ASIO_NOEXCEPT + { + executor_ = ASIO_MOVE_CAST(Executor)(other.executor_); + 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=(strand<OtherExecutor>&& other) ASIO_NOEXCEPT + { + executor_ = ASIO_MOVE_CAST(OtherExecutor)(other.executor_); + impl_ = ASIO_MOVE_CAST(implementation_type)(other.impl_); + return *this; + } +#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION) + + /// Destructor. + ~strand() ASIO_NOEXCEPT + { + } + + /// Obtain the underlying executor. + inner_executor_type get_inner_executor() const ASIO_NOEXCEPT + { + return executor_; + } + + /// Forward a query to the underlying executor. + /** + * Do not call this function directly. It is intended for use with the + * asio::query customisation point. + * + * For example: + * @code asio::strand<my_executor_type> ex = ...; + * if (asio::query(ex, asio::execution::blocking) + * == asio::execution::blocking.never) + * ... @endcode + */ + template <typename Property> + typename constraint< + can_query<const Executor&, Property>::value, + typename conditional< + is_convertible<Property, execution::blocking_t>::value, + execution::blocking_t, + typename query_result<const Executor&, Property>::type + >::type + >::type query(const Property& p) const + ASIO_NOEXCEPT_IF(( + is_nothrow_query<const Executor&, Property>::value)) + { + return this->query_helper( + is_convertible<Property, execution::blocking_t>(), p); + } + + /// Forward a requirement to the underlying executor. + /** + * Do not call this function directly. It is intended for use with the + * asio::require customisation point. + * + * For example: + * @code asio::strand<my_executor_type> ex1 = ...; + * auto ex2 = asio::require(ex1, + * asio::execution::blocking.never); @endcode + */ + template <typename Property> + typename constraint< + can_require<const Executor&, Property>::value + && !is_convertible<Property, execution::blocking_t::always_t>::value, + strand<typename decay< + typename require_result<const Executor&, Property>::type + >::type> + >::type require(const Property& p) const + ASIO_NOEXCEPT_IF(( + is_nothrow_require<const Executor&, Property>::value)) + { + return strand<typename decay< + typename require_result<const Executor&, Property>::type + >::type>(asio::require(executor_, p), impl_); + } + + /// Forward a preference to the underlying executor. + /** + * Do not call this function directly. It is intended for use with the + * asio::prefer customisation point. + * + * For example: + * @code asio::strand<my_executor_type> ex1 = ...; + * auto ex2 = asio::prefer(ex1, + * asio::execution::blocking.never); @endcode + */ + template <typename Property> + typename constraint< + can_prefer<const Executor&, Property>::value + && !is_convertible<Property, execution::blocking_t::always_t>::value, + strand<typename decay< + typename prefer_result<const Executor&, Property>::type + >::type> + >::type prefer(const Property& p) const + ASIO_NOEXCEPT_IF(( + is_nothrow_prefer<const Executor&, Property>::value)) + { + return strand<typename decay< + typename prefer_result<const Executor&, Property>::type + >::type>(asio::prefer(executor_, p), impl_); + } + +#if !defined(ASIO_NO_TS_EXECUTORS) + /// 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(); + } +#endif // !defined(ASIO_NO_TS_EXECUTORS) + + /// Request the strand to invoke the given function object. + /** + * Do not call this function directly. It is intended for use with the + * execution::execute customisation point. + * + * For example: + * @code asio::strand<my_executor_type> ex = ...; + * execution::execute(ex, my_function_object); @endcode + * + * This function is used to ask the strand to execute the given function + * object on its underlying executor. The function object will be executed + * according to the properties of the underlying executor. + * + * @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 + */ + template <typename Function> + typename constraint< + execution::can_execute<const Executor&, Function>::value, + void + >::type execute(ASIO_MOVE_ARG(Function) f) const + { + detail::strand_executor_service::execute(impl_, + executor_, ASIO_MOVE_CAST(Function)(f)); + } + +#if !defined(ASIO_NO_TS_EXECUTORS) + /// 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); + } +#endif // !defined(ASIO_NO_TS_EXECUTORS) + + /// 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_; + } + +#if defined(GENERATING_DOCUMENTATION) +private: +#endif // defined(GENERATING_DOCUMENTATION) + typedef detail::strand_executor_service::implementation_type + implementation_type; + + template <typename InnerExecutor> + static implementation_type create_implementation(const InnerExecutor& ex, + typename constraint< + can_query<InnerExecutor, execution::context_t>::value + >::type = 0) + { + return use_service<detail::strand_executor_service>( + asio::query(ex, execution::context)).create_implementation(); + } + + template <typename InnerExecutor> + static implementation_type create_implementation(const InnerExecutor& ex, + typename constraint< + !can_query<InnerExecutor, execution::context_t>::value + >::type = 0) + { + return use_service<detail::strand_executor_service>( + ex.context()).create_implementation(); + } + + strand(const Executor& ex, const implementation_type& impl) + : executor_(ex), + impl_(impl) + { + } + + template <typename Property> + typename query_result<const Executor&, Property>::type query_helper( + false_type, const Property& property) const + { + return asio::query(executor_, property); + } + + template <typename Property> + execution::blocking_t query_helper(true_type, const Property& property) const + { + execution::blocking_t result = asio::query(executor_, property); + return result == execution::blocking.always + ? execution::blocking.possibly : result; + } + + Executor executor_; + implementation_type impl_; +}; + +/** @defgroup make_strand asio::make_strand + * + * @brief The asio::make_strand function creates a @ref strand object for + * an executor or execution context. + */ +/*@{*/ + +/// Create a @ref strand object for an executor. +template <typename Executor> +inline strand<Executor> make_strand(const Executor& ex, + typename constraint< + is_executor<Executor>::value || execution::is_executor<Executor>::value + >::type = 0) +{ + return strand<Executor>(ex); +} + +/// Create a @ref strand object for an execution context. +template <typename ExecutionContext> +inline strand<typename ExecutionContext::executor_type> +make_strand(ExecutionContext& ctx, + typename constraint< + is_convertible<ExecutionContext&, execution_context&>::value + >::type = 0) +{ + return strand<typename ExecutionContext::executor_type>(ctx.get_executor()); +} + +/*@}*/ + +#if !defined(GENERATING_DOCUMENTATION) + +namespace traits { + +#if !defined(ASIO_HAS_DEDUCED_EQUALITY_COMPARABLE_TRAIT) + +template <typename Executor> +struct equality_comparable<strand<Executor> > +{ + ASIO_STATIC_CONSTEXPR(bool, is_valid = true); + ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); +}; + +#endif // !defined(ASIO_HAS_DEDUCED_EQUALITY_COMPARABLE_TRAIT) + +#if !defined(ASIO_HAS_DEDUCED_EXECUTE_MEMBER_TRAIT) + +template <typename Executor, typename Function> +struct execute_member<strand<Executor>, Function, + typename enable_if< + execution::can_execute<const Executor&, Function>::value + >::type> +{ + ASIO_STATIC_CONSTEXPR(bool, is_valid = true); + ASIO_STATIC_CONSTEXPR(bool, is_noexcept = false); + typedef void result_type; +}; + +#endif // !defined(ASIO_HAS_DEDUCED_EXECUTE_MEMBER_TRAIT) + +#if !defined(ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) + +template <typename Executor, typename Property> +struct query_member<strand<Executor>, Property, + typename enable_if< + can_query<const Executor&, Property>::value + >::type> +{ + ASIO_STATIC_CONSTEXPR(bool, is_valid = true); + ASIO_STATIC_CONSTEXPR(bool, is_noexcept = + (is_nothrow_query<Executor, Property>::value)); + typedef typename conditional< + is_convertible<Property, execution::blocking_t>::value, + execution::blocking_t, typename query_result<Executor, Property>::type + >::type result_type; +}; + +#endif // !defined(ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) + +#if !defined(ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT) + +template <typename Executor, typename Property> +struct require_member<strand<Executor>, Property, + typename enable_if< + can_require<const Executor&, Property>::value + && !is_convertible<Property, execution::blocking_t::always_t>::value + >::type> +{ + ASIO_STATIC_CONSTEXPR(bool, is_valid = true); + ASIO_STATIC_CONSTEXPR(bool, is_noexcept = + (is_nothrow_require<Executor, Property>::value)); + typedef strand<typename decay< + typename require_result<Executor, Property>::type + >::type> result_type; +}; + +#endif // !defined(ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT) + +#if !defined(ASIO_HAS_DEDUCED_PREFER_MEMBER_TRAIT) + +template <typename Executor, typename Property> +struct prefer_member<strand<Executor>, Property, + typename enable_if< + can_prefer<const Executor&, Property>::value + && !is_convertible<Property, execution::blocking_t::always_t>::value + >::type> +{ + ASIO_STATIC_CONSTEXPR(bool, is_valid = true); + ASIO_STATIC_CONSTEXPR(bool, is_noexcept = + (is_nothrow_prefer<Executor, Property>::value)); + typedef strand<typename decay< + typename prefer_result<Executor, Property>::type + >::type> result_type; +}; + +#endif // !defined(ASIO_HAS_DEDUCED_PREFER_MEMBER_TRAIT) + +} // namespace traits + +#endif // !defined(GENERATING_DOCUMENTATION) + +} // 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 |