Add experimental::append completion token adapter.
The append completion token adapter can be used to pass additional
completion handler arguments. For example:
timer.async_wait(
asio::experimental::append(
[](std::error_code ec, int i)
{
// ...
},
42)
);
std::future<int> f = timer.async_wait(
asio::experimental::append(
asio::use_future,
42
)
);
diff --git a/asio/include/Makefile.am b/asio/include/Makefile.am
index c5951ea..06acb04 100644
--- a/asio/include/Makefile.am
+++ b/asio/include/Makefile.am
@@ -342,9 +342,11 @@
asio/execution/submit.hpp \
asio/executor.hpp \
asio/executor_work_guard.hpp \
+ asio/experimental/append.hpp \
asio/experimental/as_single.hpp \
asio/experimental/as_tuple.hpp \
asio/experimental/deferred.hpp \
+ asio/experimental/impl/append.hpp \
asio/experimental/impl/as_single.hpp \
asio/experimental/impl/as_tuple.hpp \
asio/experimental/impl/deferred.hpp \
diff --git a/asio/include/asio/experimental/append.hpp b/asio/include/asio/experimental/append.hpp
new file mode 100644
index 0000000..f488b29
--- /dev/null
+++ b/asio/include/asio/experimental/append.hpp
@@ -0,0 +1,69 @@
+//
+// experimental/append.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_EXPERIMENTAL_APPEND_HPP
+#define ASIO_EXPERIMENTAL_APPEND_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <tuple>
+#include "asio/detail/type_traits.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace experimental {
+
+/// Completion token type used to specify that the completion handler
+/// arguments should be passed additional values.
+template <typename CompletionToken, typename... Values>
+class append_t
+{
+public:
+ /// Constructor.
+ template <typename T, typename... V>
+ ASIO_CONSTEXPR explicit append_t(
+ ASIO_MOVE_ARG(T) completion_token,
+ ASIO_MOVE_ARG(V)... values)
+ : token_(ASIO_MOVE_CAST(T)(completion_token)),
+ values_(ASIO_MOVE_CAST(V)(values)...)
+ {
+ }
+
+//private:
+ CompletionToken token_;
+ std::tuple<Values...> values_;
+};
+
+/// Create a completion token to specify that the completion handler arguments
+/// should be combined into a single tuple argument.
+template <typename CompletionToken, typename... Values>
+inline ASIO_CONSTEXPR append_t<
+ typename decay<CompletionToken>::type, typename decay<Values>::type...>
+append(ASIO_MOVE_ARG(CompletionToken) completion_token,
+ ASIO_MOVE_ARG(Values)... values)
+{
+ return append_t<
+ typename decay<CompletionToken>::type, typename decay<Values>::type...>(
+ ASIO_MOVE_CAST(CompletionToken)(completion_token),
+ ASIO_MOVE_CAST(Values)(values)...);
+}
+
+} // namespace experimental
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#include "asio/experimental/impl/append.hpp"
+
+#endif // ASIO_EXPERIMENTAL_APPEND_HPP
diff --git a/asio/include/asio/experimental/impl/append.hpp b/asio/include/asio/experimental/impl/append.hpp
new file mode 100644
index 0000000..d377ca2
--- /dev/null
+++ b/asio/include/asio/experimental/impl/append.hpp
@@ -0,0 +1,216 @@
+//
+// experimental/impl/append.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_IMPL_EXPERIMENTAL_APPEND_HPP
+#define ASIO_IMPL_EXPERIMENTAL_APPEND_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+
+#include "asio/associator.hpp"
+#include "asio/async_result.hpp"
+#include "asio/detail/handler_alloc_helpers.hpp"
+#include "asio/detail/handler_cont_helpers.hpp"
+#include "asio/detail/handler_invoke_helpers.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/detail/variadic_templates.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace experimental {
+namespace detail {
+
+// Class to adapt a append_t as a completion handler.
+template <typename Handler, typename... Values>
+class append_handler
+{
+public:
+ typedef void result_type;
+
+ template <typename H>
+ append_handler(ASIO_MOVE_ARG(H) handler, std::tuple<Values...> values)
+ : handler_(ASIO_MOVE_CAST(H)(handler)),
+ values_(ASIO_MOVE_CAST(std::tuple<Values...>)(values))
+ {
+ }
+
+ template <typename... Args>
+ void operator()(ASIO_MOVE_ARG(Args)... args)
+ {
+ this->invoke(
+ std::make_index_sequence<sizeof...(Values)>{},
+ ASIO_MOVE_CAST(Args)(args)...);
+ }
+
+ template <std::size_t... I, typename... Args>
+ void invoke(std::index_sequence<I...>, ASIO_MOVE_ARG(Args)... args)
+ {
+ ASIO_MOVE_OR_LVALUE(Handler)(handler_)(
+ ASIO_MOVE_CAST(Args)(args)...,
+ ASIO_MOVE_CAST(Values)(std::get<I>(values_))...);
+ }
+
+//private:
+ Handler handler_;
+ std::tuple<Values...> values_;
+};
+
+template <typename Handler>
+inline asio_handler_allocate_is_deprecated
+asio_handler_allocate(std::size_t size,
+ append_handler<Handler>* this_handler)
+{
+#if defined(ASIO_NO_DEPRECATED)
+ asio_handler_alloc_helpers::allocate(size, this_handler->handler_);
+ return asio_handler_allocate_is_no_longer_used();
+#else // defined(ASIO_NO_DEPRECATED)
+ return asio_handler_alloc_helpers::allocate(
+ size, this_handler->handler_);
+#endif // defined(ASIO_NO_DEPRECATED)
+}
+
+template <typename Handler>
+inline asio_handler_deallocate_is_deprecated
+asio_handler_deallocate(void* pointer, std::size_t size,
+ append_handler<Handler>* this_handler)
+{
+ asio_handler_alloc_helpers::deallocate(
+ pointer, size, this_handler->handler_);
+#if defined(ASIO_NO_DEPRECATED)
+ return asio_handler_deallocate_is_no_longer_used();
+#endif // defined(ASIO_NO_DEPRECATED)
+}
+
+template <typename Handler>
+inline bool asio_handler_is_continuation(
+ append_handler<Handler>* this_handler)
+{
+ return asio_handler_cont_helpers::is_continuation(
+ this_handler->handler_);
+}
+
+template <typename Function, typename Handler>
+inline asio_handler_invoke_is_deprecated
+asio_handler_invoke(Function& function,
+ append_handler<Handler>* this_handler)
+{
+ asio_handler_invoke_helpers::invoke(
+ function, this_handler->handler_);
+#if defined(ASIO_NO_DEPRECATED)
+ return asio_handler_invoke_is_no_longer_used();
+#endif // defined(ASIO_NO_DEPRECATED)
+}
+
+template <typename Function, typename Handler>
+inline asio_handler_invoke_is_deprecated
+asio_handler_invoke(const Function& function,
+ append_handler<Handler>* this_handler)
+{
+ asio_handler_invoke_helpers::invoke(
+ function, this_handler->handler_);
+#if defined(ASIO_NO_DEPRECATED)
+ return asio_handler_invoke_is_no_longer_used();
+#endif // defined(ASIO_NO_DEPRECATED)
+}
+
+template <typename Signature, typename... Values>
+struct append_signature;
+
+template <typename R, typename... Args, typename... Values>
+struct append_signature<R(Args...), Values...>
+{
+ typedef R type(typename decay<Args>::type..., Values...);
+};
+
+} // namespace detail
+} // namespace experimental
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+template <typename CompletionToken, typename... Values, typename Signature>
+struct async_result<
+ experimental::append_t<CompletionToken, Values...>, Signature>
+ : async_result<CompletionToken,
+ typename experimental::detail::append_signature<
+ Signature, Values...>::type>
+{
+ typedef typename experimental::detail::append_signature<
+ Signature, Values...>::type signature;
+
+ template <typename Initiation>
+ struct init_wrapper
+ {
+ init_wrapper(Initiation init)
+ : initiation_(ASIO_MOVE_CAST(Initiation)(init))
+ {
+ }
+
+ template <typename Handler, typename... Args>
+ void operator()(
+ ASIO_MOVE_ARG(Handler) handler,
+ std::tuple<Values...> values,
+ ASIO_MOVE_ARG(Args)... args)
+ {
+ ASIO_MOVE_CAST(Initiation)(initiation_)(
+ experimental::detail::append_handler<
+ typename decay<Handler>::type, Values...>(
+ ASIO_MOVE_CAST(Handler)(handler),
+ ASIO_MOVE_CAST(std::tuple<Values...>)(values)),
+ ASIO_MOVE_CAST(Args)(args)...);
+ }
+
+ Initiation initiation_;
+ };
+
+ template <typename Initiation, typename RawCompletionToken, typename... Args>
+ static ASIO_INITFN_DEDUCED_RESULT_TYPE(CompletionToken, signature,
+ (async_initiate<CompletionToken, signature>(
+ declval<init_wrapper<typename decay<Initiation>::type> >(),
+ declval<CompletionToken&>(),
+ declval<ASIO_MOVE_ARG(Args)>()...)))
+ initiate(
+ ASIO_MOVE_ARG(Initiation) initiation,
+ ASIO_MOVE_ARG(RawCompletionToken) token,
+ ASIO_MOVE_ARG(Args)... args)
+ {
+ return async_initiate<CompletionToken, signature>(
+ init_wrapper<typename decay<Initiation>::type>(
+ ASIO_MOVE_CAST(Initiation)(initiation)),
+ token.token_,
+ ASIO_MOVE_CAST(std::tuple<Values...>)(token.values_),
+ ASIO_MOVE_CAST(Args)(args)...);
+ }
+};
+
+template <template <typename, typename> class Associator,
+ typename Handler, typename DefaultCandidate>
+struct associator<Associator,
+ experimental::detail::append_handler<Handler>, DefaultCandidate>
+ : Associator<Handler, DefaultCandidate>
+{
+ static typename Associator<Handler, DefaultCandidate>::type get(
+ const experimental::detail::append_handler<Handler>& h,
+ const DefaultCandidate& c = DefaultCandidate()) ASIO_NOEXCEPT
+ {
+ return Associator<Handler, DefaultCandidate>::get(h.handler_, c);
+ }
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_EXPERIMENTAL_APPEND_HPP
