Added thirdparty: boost library

thirdparty/include/boost/cobalt/detail/await_result_helper.hpp

@@ -0,0 +1,82 @@
+//
+// Copyright (c) 2022 Klemens Morgenstern (klemens.morgenstern@gmx.net)
+//
+// 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_COBALT_DETAIL_AWAIT_RESULT_HELPER_HPP
+#define BOOST_COBALT_DETAIL_AWAIT_RESULT_HELPER_HPP
+
+#include <boost/cobalt/concepts.hpp>
+#include <utility>
+
+namespace boost::cobalt::detail
+{
+
+template<awaitable_type T>
+auto co_await_result_helper() -> decltype(std::declval<T&>());
+
+template<typename T>
+auto co_await_result_helper() -> decltype(std::declval<T>().operator co_await());
+
+template<typename T>
+auto co_await_result_helper() -> decltype(operator co_await(std::declval<T>()));
+
+template<typename T>
+using co_awaitable_type = decltype(co_await_result_helper<T>());
+
+template<typename T>
+using co_await_result_t = decltype(co_await_result_helper<T>().await_resume());
+
+template<awaitable_type T>
+T&& get_awaitable_type(T && t) { return std::forward<T>(t);}
+
+template<typename T>
+  requires (requires (T && t) {{operator co_await(std::forward<T>(t))} -> awaitable_type;} )
+decltype(auto) get_awaitable_type(T && t) { return operator co_await(std::forward<T>(t));}
+
+template<typename T>
+requires (requires (T && t) {{std::forward<T>(t).operator co_await()} -> awaitable_type;} )
+decltype(auto) get_awaitable_type(T && t)  { return std::forward<T>(t).operator co_await();}
+
+template<typename T>
+struct awaitable_type_getter
+{
+  using type = co_awaitable_type<T&&>;
+  std::decay_t<T> & ref;
+
+  template<typename U>
+  awaitable_type_getter(U && ref) : ref(ref) {}
+
+  operator type ()
+  {
+    if constexpr (std::is_lvalue_reference_v<T>)
+      return get_awaitable_type(ref);
+    else
+      return get_awaitable_type(std::move(ref));
+  }
+};
+
+
+template<awaitable_type T>
+  struct awaitable_type_getter<T>
+{
+  using type = T&&;
+  std::decay_t<T> & ref;
+
+  template<typename U>
+  awaitable_type_getter(U && ref) : ref(ref) {}
+
+  operator type ()
+  {
+    if constexpr (std::is_lvalue_reference_v<T>)
+      return ref;
+    else
+      return std::move(ref);
+  }
+};
+
+}
+
+#endif //BOOST_COBALT_DETAIL_AWAIT_RESULT_HELPER_HPP