From f61014d99d1fffe6beed9a891ecf2e6515cc9ca2 Mon Sep 17 00:00:00 2001
From: Klemens <klemens.d.morgenstern@gmail.com>
Date: Sun, 10 Mar 2024 14:21:41 +0800
Subject: [PATCH] first step on custom coro frame hacking.

---
 .drone.star                                 |  1 +
 include/boost/cobalt/experimental/fiber.hpp | 38 +++++++++++++++++++++
 test/CMakeLists.txt                         |  7 +++-
 test/Jamfile.jam                            |  1 +
 test/experimental/fiber.cpp                 | 27 +++++++++++++++
 5 files changed, 73 insertions(+), 1 deletion(-)
 create mode 100644 include/boost/cobalt/experimental/fiber.hpp
 create mode 100644 test/experimental/fiber.cpp

diff --git a/.drone.star b/.drone.star
index d507de30..aa7cd95f 100644
--- a/.drone.star
+++ b/.drone.star
@@ -18,6 +18,7 @@ deps = [
     'libs/concept_check',
     'libs/config',
     'libs/container',
+    'libs/context',
     'libs/core',
     'libs/date_time',
     'libs/detail',
diff --git a/include/boost/cobalt/experimental/fiber.hpp b/include/boost/cobalt/experimental/fiber.hpp
new file mode 100644
index 00000000..0605ec40
--- /dev/null
+++ b/include/boost/cobalt/experimental/fiber.hpp
@@ -0,0 +1,38 @@
+// Copyright (c) 2023 Klemens D. Morgenstern
+//
+// 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_FIBER_HPP
+#define BOOST_COBALT_FIBER_HPP
+
+#include <boost/context/fiber.hpp>
+
+// this is all UB according to the standard. BUT it shouldn't be!
+
+namespace boost::cobalt::experimental
+{
+
+namespace detail
+{
+
+struct fiber_promise
+{
+
+};
+
+struct fiber_frame
+{
+  void (*resume_) (fiber_frame *) = +[](fiber_frame * ff) { ff->resume();};
+  void (*destroy_)(fiber_frame *) = +[](fiber_frame * ff) { ff->destroy();};
+
+  fiber_promise promise;
+
+  void resume() {}
+  void destroy() {}
+};
+
+}
+
+}
+
+#endif //BOOST_COBALT_FIBER_HPP
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 032ff54b..928a65da 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -21,4 +21,9 @@ add_test(NAME boost_cobalt_main COMMAND boost_cobalt_main)
 add_test(NAME boost_cobalt_basic_tests COMMAND boost_cobalt_basic_tests)
 target_compile_features(boost_cobalt PUBLIC cxx_std_20)
 
-add_dependencies(tests boost_cobalt_main boost_cobalt_basic_tests boost_cobalt_static_tests)
+
+add_executable(boost_cobalt_experimental test_main.cpp experimental/fiber.cpp)
+target_link_libraries(boost_cobalt_experimental  Boost::cobalt Boost::unit_test_framework Boost::context)
+add_test(NAME boost_cobalt_experimental COMMAND boost_cobalt_experimental)
+
+add_dependencies(tests boost_cobalt_main boost_cobalt_basic_tests boost_cobalt_static_tests boost_cobalt_experimental)
diff --git a/test/Jamfile.jam b/test/Jamfile.jam
index 450c8ea4..34b96dd6 100644
--- a/test/Jamfile.jam
+++ b/test/Jamfile.jam
@@ -32,3 +32,4 @@ for local src in [ glob *.cpp : main.cpp main_compile.cpp test_main.cpp concepts
    run $(src) test_impl ;
 }
 
+run experimental/fiber.cpp test_impl ;
\ No newline at end of file
diff --git a/test/experimental/fiber.cpp b/test/experimental/fiber.cpp
new file mode 100644
index 00000000..e43c4d69
--- /dev/null
+++ b/test/experimental/fiber.cpp
@@ -0,0 +1,27 @@
+// Copyright (c) 2023 Klemens D. Morgenstern
+//
+// 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)
+
+#include <boost/cobalt/experimental/fiber.hpp>
+
+#include "../test.hpp"
+
+BOOST_AUTO_TEST_SUITE(fiber);
+
+BOOST_AUTO_TEST_CASE(basics)
+{
+  boost::cobalt::experimental::detail::fiber_frame ff;
+
+  using pro = boost::cobalt::experimental::detail::fiber_promise;
+  auto hh = std::coroutine_handle<pro>::from_address(&ff);
+  BOOST_CHECK(!hh.done());
+  ff.resume_ = nullptr;
+  BOOST_CHECK(hh.done());
+
+  BOOST_CHECK(&ff.promise == &hh.promise());
+  BOOST_CHECK(std::coroutine_handle<pro>::from_promise(ff.promise).address() == &ff);
+}
+
+
+BOOST_AUTO_TEST_SUITE_END();
\ No newline at end of file