From d7c16fd073ee719a1c72a9d13828b712fc8f5674 Mon Sep 17 00:00:00 2001
From: Alecto <perez.cs@pm.me>
Date: Thu, 27 Aug 2020 13:49:48 -0600
Subject: [PATCH] Added suspend_invoke and tags::on_resume

---
 CMakeLists.txt                           |  2 +-
 README.md                                |  2 +-
 VERSION                                  |  2 +-
 include/conduit/async/suspend_invoke.hpp | 42 ++++++++++++++++++++++++
 include/conduit/util/tag_types.hpp       |  7 +++-
 main.cpp                                 | 12 ++++++-
 6 files changed, 62 insertions(+), 5 deletions(-)
 create mode 100644 include/conduit/async/suspend_invoke.hpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3d9b0cf..93c99b1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.0.0)
-project(conduit VERSION 0.1.2 LANGUAGES CXX)
+project(conduit VERSION 0.2.0 LANGUAGES CXX)
 
 option(CONDUIT_Install "Install CMake targets during install step." ON)
 
diff --git a/README.md b/README.md
index b127453..4c53506 100644
--- a/README.md
+++ b/README.md
@@ -74,7 +74,7 @@ rm -rf conduit
 
 On Ubuntu, installation would be as follows:
 
-1. Download [conduit.deb](https://github.com/functionalperez/conduit/releases/download/v0.1.2/conduit_0.1.2-0_all.deb) (This is a download link)
+1. Download [conduit.deb](https://github.com/functionalperez/conduit/releases/download/v0.2.0/conduit_0.2.0-0_all.deb) (This is a download link)
 2. Go to your downloads folder (`cd ~/Downloads`)
 3. Run `sudo apt install ./conduit.deb` (or just double-click the file to open it in the installer)
 
diff --git a/VERSION b/VERSION
index d917d3e..0ea3a94 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.1.2
+0.2.0
diff --git a/include/conduit/async/suspend_invoke.hpp b/include/conduit/async/suspend_invoke.hpp
new file mode 100644
index 0000000..a21ab52
--- /dev/null
+++ b/include/conduit/async/suspend_invoke.hpp
@@ -0,0 +1,42 @@
+#pragma once
+#include <conduit/mixin/resumable.hpp>
+#include <conduit/util/concepts.hpp>
+#include <conduit/util/tag_types.hpp>
+
+namespace conduit {
+// clang-format off
+template <class Func>
+concept on_suspend_callback = requires(Func func, std::coroutine_handle<> h) {
+    { func(h) } -> same_as<void>;
+};
+
+template <class Func>
+concept on_resume_callback = requires(Func func) {
+    { func(tags::on_resume) };
+};
+// clang-format on
+} // namespace conduit
+
+namespace conduit::async {
+template <class Func>
+struct suspend_invoke_container {
+    [[no_unique_address]] Func on_suspend;
+};
+
+template <class Func>
+struct suspend_invoke : suspend_invoke_container<Func>,
+                        mixin::Resumable<suspend_invoke<Func>> {
+    using suspend_invoke_container<Func>::on_suspend;
+    using mixin::Resumable<suspend_invoke<Func>>::await_resume;
+    decltype(auto) await_resume() {
+        if constexpr (conduit::on_resume_callback<decltype(on_suspend)>) {
+            return on_suspend(tags::on_resume);
+        } else {
+            return;
+        }
+    }
+};
+
+template <on_suspend_callback Func>
+suspend_invoke(Func) -> suspend_invoke<Func>;
+} // namespace conduit::async
\ No newline at end of file
diff --git a/include/conduit/util/tag_types.hpp b/include/conduit/util/tag_types.hpp
index 7e668b7..7d3d190 100644
--- a/include/conduit/util/tag_types.hpp
+++ b/include/conduit/util/tag_types.hpp
@@ -2,6 +2,11 @@
 #include <conduit/util/concepts.hpp>
 
 namespace conduit::tags {
+struct on_resume_t {
+    explicit on_resume_t() = default;
+};
+constexpr auto on_resume = on_resume_t();
+
 struct get_promise_t {
     explicit get_promise_t() = default;
 };
@@ -30,4 +35,4 @@ struct nothing_t {
 };
 constexpr auto nothing = nothing_t();
 
-} // namespace conduit
+} // namespace conduit::tags
diff --git a/main.cpp b/main.cpp
index d1ec4ac..03f478b 100644
--- a/main.cpp
+++ b/main.cpp
@@ -6,6 +6,7 @@
 #include <conduit/source.hpp>
 #include <conduit/task.hpp>
 #include <conduit/async/destroy.hpp>
+#include <conduit/async/suspend_invoke.hpp>
 #include <cstdio>
 #include <cstdlib>
 #include <iostream>
@@ -72,7 +73,6 @@ future<std::string> test_generator(std::string on_success) {
     co_return std::string(begin(g), end(g));
 }
 
-
 future<std::string> test_on_suspend(std::string on_success) {
     std::string result;
     auto f = [](std::coroutine_handle<> h, std::string& result, std::string& on_success) {
@@ -112,6 +112,15 @@ future<std::string> test_source(std::string on_success) {
     co_return result;
 }
 
+future<std::string> test_suspend_invoke(std::string on_success) {
+    std::string result;
+    co_await async::suspend_invoke{[&](std::coroutine_handle<> h) {
+        result = on_success;
+        h.resume();
+    }};
+    co_return result;
+}
+
 future<std::string> test_task(std::string on_success) {
     auto coro = [&](std::string& s) -> task {
         s = on_success;
@@ -133,6 +142,7 @@ coroutine run_tests() {
     RUN_TEST(test_on_suspend);
     RUN_TEST(test_recursive_generator);
     RUN_TEST(test_source);
+    RUN_TEST(test_suspend_invoke);
     RUN_TEST(test_task);
 }