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- //
- // package.hpp
- // ~~~~~~~~~~~
- //
- // Copyright (c) 2003-2015 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_USE_PACKAGE_HPP
- #define ASIO_USE_PACKAGE_HPP
-
- #if defined(_MSC_VER) && (_MSC_VER >= 1200)
- # pragma once
- #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
-
- #include "asio/detail/config.hpp"
- #include <future>
- #include <memory>
- #include "asio/async_result.hpp"
- #include "asio/detail/type_traits.hpp"
- #include "asio/detail/variadic_templates.hpp"
- #include "asio/handler_type.hpp"
-
- #include "asio/detail/push_options.hpp"
-
- namespace asio {
-
- /// Class to enable lazy construction of a packaged_task from a completion
- /// token.
- /**
- * The packaged_token class is used to adapt a function object as a packaged
- * task. When this adapter is passed as a completion token to an asynchronous
- * operation, the result of the function object is retuned via a std::future.
- *
- * Use the @ref package function rather than using this class directly.
- */
- template <typename Function, typename Allocator = std::allocator<void> >
- class packaged_token
- {
- public:
- /// The allocator type. The allocator is used when constructing the
- /// @c std::promise object for a given asynchronous operation.
- typedef Allocator allocator_type;
-
- /// Construct using specified allocator.
- explicit packaged_token(Function f)
- : func_(std::move(f))
- {
- }
-
- /// Construct using specified allocator.
- packaged_token(Function f, const Allocator& allocator)
- : func_(std::move(f)),
- allocator_(allocator)
- {
- }
-
- /// Obtain allocator.
- allocator_type get_allocator() const ASIO_NOEXCEPT
- {
- return allocator_;
- }
-
- private:
- template <class, class> friend class packaged_handler;
- Function func_;
- Allocator allocator_;
- };
-
- /// A packaged_task with an associated allocator.
- template <typename Signature, typename Allocator>
- class packaged_handler : public std::packaged_task<Signature>
- {
- public:
- /// The allocator type. The allocator is used when constructing the
- /// @c std::promise object for a given asynchronous operation.
- typedef Allocator allocator_type;
-
- /// Construct from a packaged token.
- template <typename Function>
- packaged_handler(
- packaged_token<Function, Allocator>&& token)
- #if defined(_MSC_VER)
- : std::packaged_task<Signature>(std::move(token.func_)),
- #elif defined(ASIO_HAS_CLANG_LIBCXX)
- : std::packaged_task<Signature>(std::allocator_arg,
- typename std::allocator_traits<
- Allocator>::template rebind_alloc<char>(token.allocator_),
- std::move(token.func_)),
- #else
- : std::packaged_task<Signature>(std::allocator_arg,
- token.allocator_, std::move(token.func_)),
- #endif
- allocator_(token.allocator_)
- {
- }
-
- /// Move construct from another packaged handler.
- packaged_handler(packaged_handler&& other)
- : std::packaged_task<Signature>(
- static_cast<std::packaged_task<Signature>&&>(other)),
- allocator_(other.allocator_)
- {
- }
-
- /// Obtain allocator.
- allocator_type get_allocator() const ASIO_NOEXCEPT
- {
- return allocator_;
- }
-
- private:
- Allocator allocator_;
- };
-
- /// Wrap a function object in a packaged task.
- /**
- * The @c package function is used to adapt a function object as a packaged
- * task. When this adapter is passed as a completion token to an asynchronous
- * operation, the result of the function object is retuned via a std::future.
- *
- * @par Example
- *
- * @code std::future<std::size_t> fut =
- * my_socket.async_read_some(buffer,
- * package([](asio::error_code ec, std::size_t n)
- * {
- * return ec ? 0 : n;
- * }));
- * ...
- * std::size_t n = fut.get(); @endcode
- */
- template <typename Function>
- inline packaged_token<typename decay<Function>::type, std::allocator<void> >
- package(ASIO_MOVE_ARG(Function) function)
- {
- return packaged_token<typename decay<Function>::type, std::allocator<void> >(
- ASIO_MOVE_CAST(Function)(function), std::allocator<void>());
- }
-
- /// Wrap a function object in a packaged task.
- /**
- * The @c package function is used to adapt a function object as a packaged
- * task. When this adapter is passed as a completion token to an asynchronous
- * operation, the result of the function object is retuned via a std::future.
- *
- * @par Example
- *
- * @code std::future<std::size_t> fut =
- * my_socket.async_read_some(buffer,
- * package([](asio::error_code ec, std::size_t n)
- * {
- * return ec ? 0 : n;
- * }));
- * ...
- * std::size_t n = fut.get(); @endcode
- */
- template <typename Function, typename Allocator>
- inline packaged_token<typename decay<Function>::type, Allocator> package(
- ASIO_MOVE_ARG(Function) function, const Allocator& a)
- {
- return packaged_token<typename decay<Function>::type, Allocator>(
- ASIO_MOVE_CAST(Function)(function), a);
- }
-
- #if !defined(GENERATING_DOCUMENTATION)
-
- #if defined(ASIO_HAS_VARIADIC_TEMPLATES)
-
- template <typename Function, typename Allocator, typename R, typename... Args>
- struct handler_type<packaged_token<Function, Allocator>, R(Args...)>
- {
- typedef packaged_handler<
- typename result_of<Function(Args...)>::type(Args...),
- Allocator> type;
- };
-
- #else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
-
- template <typename Function, typename Allocator, typename R>
- struct handler_type<packaged_token<Function, Allocator>, R()>
- {
- typedef packaged_handler<
- typename result_of<Function()>::type(),
- Allocator> type;
- };
-
- #define ASIO_PRIVATE_HANDLER_TYPE_DEF(n) \
- template <typename Function, typename Allocator, \
- typename R, ASIO_VARIADIC_TPARAMS(n)> \
- struct handler_type< \
- packaged_token<Function, Allocator>, R(ASIO_VARIADIC_TARGS(n))> \
- { \
- typedef packaged_handler< \
- typename result_of< \
- Function(ASIO_VARIADIC_TARGS(n))>::type( \
- ASIO_VARIADIC_TARGS(n)), \
- Allocator> type; \
- }; \
- /**/
- ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_HANDLER_TYPE_DEF)
- #undef ASIO_PRIVATE_HANDLER_TYPE_DEF
-
- #endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
-
- #if defined(ASIO_HAS_VARIADIC_TEMPLATES)
-
- template <typename R, typename... Args>
- class async_result<std::packaged_task<R(Args...)> >
- {
- public:
- typedef std::future<R> type;
-
- explicit async_result(std::packaged_task<R(Args...)>& h)
- : future_(h.get_future())
- {
- }
-
- type get()
- {
- return std::move(future_);
- }
-
- private:
- type future_;
- };
-
- #else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
-
- template <typename R>
- class async_result<std::packaged_task<R()> >
- {
- public:
- typedef std::future<R> type;
-
- explicit async_result(std::packaged_task<R()>& h)
- : future_(h.get_future())
- {
- }
-
- type get()
- {
- return std::move(future_);
- }
-
- private:
- type future_;
- };
-
- #define ASIO_PRIVATE_ASYNC_RESULT_DEF(n) \
- template <typename R, ASIO_VARIADIC_TPARAMS(n)> \
- class async_result<std::packaged_task<R(ASIO_VARIADIC_TARGS(n))> > \
- { \
- public: \
- typedef std::future<R> type; \
- \
- explicit async_result( \
- std::packaged_task<R(ASIO_VARIADIC_TARGS(n))>& h) \
- : future_(h.get_future()) \
- { \
- } \
- \
- type get() \
- { \
- return std::move(future_); \
- } \
- \
- private: \
- type future_; \
- }; \
- /**/
- ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_ASYNC_RESULT_DEF)
- #undef ASIO_PRIVATE_ASYNC_RESULT_DEF
-
- #endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
-
- template <typename Signature, typename Allocator>
- class async_result<packaged_handler<Signature, Allocator>>
- : public async_result<std::packaged_task<Signature>>
- {
- public:
- explicit async_result(packaged_handler<Signature, Allocator>& h)
- : async_result<std::packaged_task<Signature>>(h) {}
- };
-
- #endif // !defined(GENERATING_DOCUMENTATION)
-
- } // namespace asio
-
- #include "asio/detail/pop_options.hpp"
-
- #endif // ASIO_USE_PACKAGE_HPP
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