--- /dev/null
+//
+// execution/start.hpp
+// ~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2020 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 BOOST_ASIO_EXECUTION_START_HPP
+#define BOOST_ASIO_EXECUTION_START_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <boost/asio/detail/config.hpp>
+#include <boost/asio/detail/type_traits.hpp>
+#include <boost/asio/traits/start_member.hpp>
+#include <boost/asio/traits/start_free.hpp>
+
+#include <boost/asio/detail/push_options.hpp>
+
+#if defined(GENERATING_DOCUMENTATION)
+
+namespace boost {
+namespace asio {
+namespace execution {
+
+/// A customisation point that notifies an operation state object to start
+/// its associated operation.
+/**
+ * The name <tt>execution::start</tt> denotes a customisation point object.
+ * The expression <tt>execution::start(R)</tt> for some subexpression
+ * <tt>R</tt> is expression-equivalent to:
+ *
+ * @li <tt>R.start()</tt>, if that expression is valid.
+ *
+ * @li Otherwise, <tt>start(R)</tt>, if that expression is valid, with
+ * overload resolution performed in a context that includes the declaration
+ * <tt>void start();</tt> and that does not include a declaration of
+ * <tt>execution::start</tt>.
+ *
+ * @li Otherwise, <tt>execution::start(R)</tt> is ill-formed.
+ */
+inline constexpr unspecified start = unspecified;
+
+/// A type trait that determines whether a @c start expression is
+/// well-formed.
+/**
+ * Class template @c can_start is a trait that is derived from
+ * @c true_type if the expression <tt>execution::start(std::declval<R>(),
+ * std::declval<E>())</tt> is well formed; otherwise @c false_type.
+ */
+template <typename R>
+struct can_start :
+ integral_constant<bool, automatically_determined>
+{
+};
+
+} // namespace execution
+} // namespace asio
+} // namespace boost
+
+#else // defined(GENERATING_DOCUMENTATION)
+
+namespace asio_execution_start_fn {
+
+using boost::asio::decay;
+using boost::asio::declval;
+using boost::asio::enable_if;
+using boost::asio::traits::start_free;
+using boost::asio::traits::start_member;
+
+void start();
+
+enum overload_type
+{
+ call_member,
+ call_free,
+ ill_formed
+};
+
+template <typename R, typename = void>
+struct call_traits
+{
+ BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = ill_formed);
+ BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = false);
+ typedef void result_type;
+};
+
+template <typename R>
+struct call_traits<R,
+ typename enable_if<
+ (
+ start_member<R>::is_valid
+ )
+ >::type> :
+ start_member<R>
+{
+ BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = call_member);
+};
+
+template <typename R>
+struct call_traits<R,
+ typename enable_if<
+ (
+ !start_member<R>::is_valid
+ &&
+ start_free<R>::is_valid
+ )
+ >::type> :
+ start_free<R>
+{
+ BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = call_free);
+};
+
+struct impl
+{
+#if defined(BOOST_ASIO_HAS_MOVE)
+ template <typename R>
+ BOOST_ASIO_CONSTEXPR typename enable_if<
+ call_traits<R>::overload == call_member,
+ typename call_traits<R>::result_type
+ >::type
+ operator()(R&& r) const
+ BOOST_ASIO_NOEXCEPT_IF((
+ call_traits<R>::is_noexcept))
+ {
+ return BOOST_ASIO_MOVE_CAST(R)(r).start();
+ }
+
+ template <typename R>
+ BOOST_ASIO_CONSTEXPR typename enable_if<
+ call_traits<R>::overload == call_free,
+ typename call_traits<R>::result_type
+ >::type
+ operator()(R&& r) const
+ BOOST_ASIO_NOEXCEPT_IF((
+ call_traits<R>::is_noexcept))
+ {
+ return start(BOOST_ASIO_MOVE_CAST(R)(r));
+ }
+#else // defined(BOOST_ASIO_HAS_MOVE)
+ template <typename R>
+ BOOST_ASIO_CONSTEXPR typename enable_if<
+ call_traits<R&>::overload == call_member,
+ typename call_traits<R&>::result_type
+ >::type
+ operator()(R& r) const
+ BOOST_ASIO_NOEXCEPT_IF((
+ call_traits<R&>::is_noexcept))
+ {
+ return r.start();
+ }
+
+ template <typename R>
+ BOOST_ASIO_CONSTEXPR typename enable_if<
+ call_traits<const R&>::overload == call_member,
+ typename call_traits<const R&>::result_type
+ >::type
+ operator()(const R& r) const
+ BOOST_ASIO_NOEXCEPT_IF((
+ call_traits<const R&>::is_noexcept))
+ {
+ return r.start();
+ }
+
+ template <typename R>
+ BOOST_ASIO_CONSTEXPR typename enable_if<
+ call_traits<R&>::overload == call_free,
+ typename call_traits<R&>::result_type
+ >::type
+ operator()(R& r) const
+ BOOST_ASIO_NOEXCEPT_IF((
+ call_traits<R&>::is_noexcept))
+ {
+ return start(r);
+ }
+
+ template <typename R>
+ BOOST_ASIO_CONSTEXPR typename enable_if<
+ call_traits<const R&>::overload == call_free,
+ typename call_traits<const R&>::result_type
+ >::type
+ operator()(const R& r) const
+ BOOST_ASIO_NOEXCEPT_IF((
+ call_traits<const R&>::is_noexcept))
+ {
+ return start(r);
+ }
+#endif // defined(BOOST_ASIO_HAS_MOVE)
+};
+
+template <typename T = impl>
+struct static_instance
+{
+ static const T instance;
+};
+
+template <typename T>
+const T static_instance<T>::instance = {};
+
+} // namespace asio_execution_start_fn
+namespace boost {
+namespace asio {
+namespace execution {
+namespace {
+
+static BOOST_ASIO_CONSTEXPR const asio_execution_start_fn::impl&
+ start = asio_execution_start_fn::static_instance<>::instance;
+
+} // namespace
+
+template <typename R>
+struct can_start :
+ integral_constant<bool,
+ asio_execution_start_fn::call_traits<R>::overload !=
+ asio_execution_start_fn::ill_formed>
+{
+};
+
+#if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
+
+template <typename R>
+constexpr bool can_start_v = can_start<R>::value;
+
+#endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
+
+template <typename R>
+struct is_nothrow_start :
+ integral_constant<bool,
+ asio_execution_start_fn::call_traits<R>::is_noexcept>
+{
+};
+
+#if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
+
+template <typename R>
+constexpr bool is_nothrow_start_v
+ = is_nothrow_start<R>::value;
+
+#endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
+
+} // namespace execution
+} // namespace asio
+} // namespace boost
+
+#endif // defined(GENERATING_DOCUMENTATION)
+
+#include <boost/asio/detail/pop_options.hpp>
+
+#endif // BOOST_ASIO_EXECUTION_START_HPP
projects / ceph.git / blobdiff