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include/asio/experimental/co_spawn.hpp

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+//
+// experimental/co_spawn.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2021-2023 Klemens D. Morgenstern
+//                         (klemens dot morgenstern at gmx dot 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 ASIO_EXPERIMENTAL_CO_SPAWN_HPP
+#define ASIO_EXPERIMENTAL_CO_SPAWN_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/config.hpp"
+#include <utility>
+#include "asio/compose.hpp"
+#include "asio/deferred.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/experimental/coro.hpp"
+#include "asio/prepend.hpp"
+#include "asio/redirect_error.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+namespace experimental {
+namespace detail {
+
+template <typename T, typename U, typename Executor>
+struct coro_spawn_op
+{
+  coro<T, U, Executor> c;
+
+  void operator()(auto& self)
+  {
+    auto op = c.async_resume(deferred);
+    std::move(op)((prepend)(std::move(self), 0));
+  }
+
+  void operator()(auto& self, int, auto... res)
+  {
+    self.complete(std::move(res)...);
+  }
+};
+
+} // namespace detail
+
+/// Spawn a resumable coroutine.
+/**
+ * This function spawns the coroutine for execution on its executor. It binds
+ * the lifetime of the coroutine to the executor.
+ *
+ * @param c The coroutine
+ *
+ * @param token The completion token
+ *
+ * @returns Implementation defined
+ */
+template <typename T, typename Executor, typename CompletionToken>
+ASIO_INITFN_AUTO_RESULT_TYPE(
+    CompletionToken, void(std::exception_ptr, T))
+co_spawn(coro<void, T, Executor> c, CompletionToken&& token)
+{
+  auto exec = c.get_executor();
+  return async_compose<CompletionToken, void(std::exception_ptr, T)>(
+      detail::coro_spawn_op<void, T, Executor>{std::move(c)},
+      token, exec);
+}
+
+/// Spawn a resumable coroutine.
+/**
+ * This function spawns the coroutine for execution on its executor. It binds
+ * the lifetime of the coroutine to the executor.
+ *
+ * @param c The coroutine
+ *
+ * @param token The completion token
+ *
+ * @returns Implementation defined
+ */
+template <typename T, typename Executor, typename CompletionToken>
+ASIO_INITFN_AUTO_RESULT_TYPE(
+    CompletionToken, void(std::exception_ptr, T))
+co_spawn(coro<void(), T, Executor> c, CompletionToken&& token)
+{
+  auto exec = c.get_executor();
+  return async_compose<CompletionToken, void(std::exception_ptr, T)>(
+      detail::coro_spawn_op<void(), T, Executor>{std::move(c)},
+      token, exec);
+}
+
+/// Spawn a resumable coroutine.
+/**
+ * This function spawns the coroutine for execution on its executor. It binds
+ * the lifetime of the coroutine to the executor.
+ *
+ * @param c The coroutine
+ *
+ * @param token The completion token
+ *
+ * @returns Implementation defined
+ */
+template <typename T, typename Executor, typename CompletionToken>
+ASIO_INITFN_AUTO_RESULT_TYPE(CompletionToken, void(T))
+co_spawn(coro<void() noexcept, T, Executor> c, CompletionToken&& token)
+{
+  auto exec = c.get_executor();
+  return async_compose<CompletionToken, void(T)>(
+      detail::coro_spawn_op<void() noexcept, T, Executor>{std::move(c)},
+      token, exec);
+}
+
+/// Spawn a resumable coroutine.
+/**
+ * This function spawns the coroutine for execution on its executor. It binds
+ * the lifetime of the coroutine to the executor.
+ *
+ * @param c The coroutine
+ *
+ * @param token The completion token
+ *
+ * @returns Implementation defined
+ */
+template <typename Executor, typename CompletionToken>
+ASIO_INITFN_AUTO_RESULT_TYPE(
+    CompletionToken, void(std::exception_ptr))
+co_spawn(coro<void, void, Executor> c, CompletionToken&& token)
+{
+  auto exec = c.get_executor();
+  return async_compose<CompletionToken, void(std::exception_ptr)>(
+      detail::coro_spawn_op<void, void, Executor>{std::move(c)},
+      token, exec);
+}
+
+/// Spawn a resumable coroutine.
+/**
+ * This function spawns the coroutine for execution on its executor. It binds
+ * the lifetime of the coroutine to the executor.
+ *
+ * @param c The coroutine
+ *
+ * @param token The completion token
+ *
+ * @returns Implementation defined
+ */
+template <typename Executor, typename CompletionToken>
+ASIO_INITFN_AUTO_RESULT_TYPE(
+    CompletionToken, void(std::exception_ptr))
+co_spawn(coro<void(), void, Executor> c, CompletionToken&& token)
+{
+  auto exec = c.get_executor();
+  return async_compose<CompletionToken, void(std::exception_ptr)>(
+      detail::coro_spawn_op<void(), void, Executor>{std::move(c)},
+      token, exec);
+}
+
+/// Spawn a resumable coroutine.
+/**
+ * This function spawns the coroutine for execution on its executor. It binds
+ * the lifetime of the coroutine to the executor.
+ *
+ * @param c The coroutine
+ *
+ * @param token The completion token
+ *
+ * @returns Implementation defined
+ */
+template <typename Executor, typename CompletionToken>
+ASIO_INITFN_AUTO_RESULT_TYPE(CompletionToken, void())
+co_spawn(coro<void() noexcept, void, Executor> c, CompletionToken&& token)
+{
+  auto exec = c.get_executor();
+  return async_compose<CompletionToken, void()>(
+      detail::coro_spawn_op<void() noexcept, void, Executor>{std::move(c)},
+      token, exec);
+}
+
+} // namespace detail
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif //ASIO_EXPERIMENTAL_CO_SPAWN_HPP