From ffd992cd74a4caef6918e589f05dfd854d8e5dfc Mon Sep 17 00:00:00 2001
From: EnderIce2 <enderice2@protonmail.com>
Date: Sat, 29 Mar 2025 23:39:44 +0000
Subject: [PATCH] refactor(kernel): improve future implementation

Signed-off-by: EnderIce2 <enderice2@protonmail.com>
---
 Kernel/Makefile                  |  2 +-
 Kernel/include_std/future        | 21 ++++++-----
 Kernel/include_std/type_traits   |  4 +-
 Kernel/library/std/future.cpp    |  8 +++-
 Kernel/tests/stl/future_test.cpp | 63 ++++++++++++++++++++++----------
 5 files changed, 64 insertions(+), 34 deletions(-)

diff --git a/Kernel/Makefile b/Kernel/Makefile
index 0585d8f3..17d8342f 100644
--- a/Kernel/Makefile
+++ b/Kernel/Makefile
@@ -67,7 +67,7 @@ ifeq ($(DEBUG), 1)
 #	CFLAGS += --coverage
 #	CFLAGS += -pg
 #	CFLAGS += -finstrument-functions
-	CFLAGS += -DDEBUG -ggdb3 -O0 -fdiagnostics-color=always -fstack-usage -fsanitize=undefined
+	CFLAGS += -DDEBUG -ggdb3 -O0 -fdiagnostics-color=always -fstack-usage -fsanitize=undefined -fdiagnostics-all-candidates
 ifeq ($(OSARCH), amd64)
 	CFLAGS += -fverbose-asm
 endif # amd64
diff --git a/Kernel/include_std/future b/Kernel/include_std/future
index 980f07ab..85e3c2bb 100644
--- a/Kernel/include_std/future
+++ b/Kernel/include_std/future
@@ -57,11 +57,7 @@ namespace std
 	};
 	error_condition make_error_condition(future_errc e) noexcept;
 
-	const error_category &future_category() noexcept
-	{
-		static const error_category cat;
-		return cat;
-	}
+	const error_category &future_category() noexcept;
 
 	inline std::error_code make_error_code(future_errc e) noexcept
 	{
@@ -155,13 +151,16 @@ namespace std
 	template <class R>
 	class promise
 	{
+	private:
 	public:
-		promise();
+		promise() = default;
+
 		template <class Allocator>
 		promise(allocator_arg_t, const Allocator &a);
-		promise(promise &&rhs) noexcept;
+
+		promise(promise &&rhs) noexcept = default;
 		promise(const promise &) = delete;
-		~promise();
+		~promise() = default;
 
 		promise &operator=(promise &&rhs) noexcept;
 		promise &operator=(const promise &) = delete;
@@ -176,7 +175,11 @@ namespace std
 
 		void set_exception(exception_ptr p);
 
-		void set_value_at_thread_exit(/* see description */);
+		void set_value_at_thread_exit(const R &value);
+		void set_value_at_thread_exit(R &&value);
+		void set_value_at_thread_exit(R &value);
+		void set_value_at_thread_exit();
+
 		void set_exception_at_thread_exit(exception_ptr p);
 	};
 
diff --git a/Kernel/include_std/type_traits b/Kernel/include_std/type_traits
index dc610ab2..b38de010 100644
--- a/Kernel/include_std/type_traits
+++ b/Kernel/include_std/type_traits
@@ -691,6 +691,6 @@ namespace std
 	template <class T>
 	using result_of_t = typename result_of<T>::type;
 
-	// template <class F, class... ArgTypes>
-	// using invoke_result_t = typename invoke_result<F, ArgTypes...>::type;
+	template <class F, class... ArgTypes>
+	using invoke_result_t = typename invoke_result<F, ArgTypes...>::type;
 }
diff --git a/Kernel/library/std/future.cpp b/Kernel/library/std/future.cpp
index 24c2b2ee..3d850b55 100644
--- a/Kernel/library/std/future.cpp
+++ b/Kernel/library/std/future.cpp
@@ -15,9 +15,13 @@
 	along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
 */
 
-// #include <future>
+#include <future>
 
 namespace std
 {
-
+	const error_category &future_category() noexcept
+	{
+		static const error_category cat;
+		return cat;
+	}
 }
diff --git a/Kernel/tests/stl/future_test.cpp b/Kernel/tests/stl/future_test.cpp
index 48e4d825..b81617cc 100644
--- a/Kernel/tests/stl/future_test.cpp
+++ b/Kernel/tests/stl/future_test.cpp
@@ -15,22 +15,45 @@
 	along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
 */
 
-// #include <future>
-// #include <thread>
-// #include <assert.h>
+#include <future>
+#include <thread>
+#include <assert.h>
 
 void test_stl_future()
 {
-	// 	{
-	// 		std::future<int> f = std::async(std::launch::async, []
-	// 										{
-	// 			for (uint64_t i = 0; i < 100000; ++i);
-	// 			return 1; });
+	// {
+	// 	std::packaged_task<int()> task([]
+	// 								   { return 7; });
+	// 	std::future<int> f1 = task.get_future();
+	// 	std::thread t(std::move(task));
 
-	// 		debug("waiting for future");
-	// 		int result = f.get();
-	// 		debug("future result is %d", result);
-	// 	}
+	// 	std::future<int> f2 = std::async(std::launch::async, []
+	// 									 { return 8; });
+
+	// 	std::promise<int> p;
+	// 	std::future<int> f3 = p.get_future();
+	// 	std::thread([&p]
+	// 				{ p.set_value_at_thread_exit(9); })
+	// 		.detach();
+
+	// 	debug("Waiting for futures...");
+	// 	f1.wait();
+	// 	f2.wait();
+	// 	f3.wait();
+	// 	debug("results: %d %d %d", f1.get(), f2.get(), f3.get());
+	// 	t.join();
+	// }
+
+	// {
+	// 	std::future<int> f = std::async(std::launch::async, []
+	// 									{
+	// 		for (uint64_t i = 0; i < 100000; ++i);
+	// 		return 1; });
+
+	// 	debug("waiting for future");
+	// 	int result = f.get();
+	// 	debug("future result is %d", result);
+	// }
 
 	// 	{
 	// 		std::promise<int> p;
@@ -57,16 +80,16 @@ void test_stl_future()
 	// 		assert(future.get() == 42);
 	// 	}
 
-	// 	{
-	// 		std::promise<int> p;
-	// 		std::future<int> f = p.get_future();
-	// 		std::shared_future<int> sf = f.share();
+	// {
+	// 	std::promise<int> p;
+	// 	std::future<int> f = p.get_future();
+	// 	std::shared_future<int> sf = f.share();
 
-	// 		p.set_value(42);
+	// 	p.set_value(42);
 
-	// 		assert(sf.get() == 42);
-	// 		assert(sf.get() == 42);
-	// 	}
+	// 	assert(sf.get() == 42);
+	// 	assert(sf.get() == 42);
+	// }
 
 	// 	{
 	// 		std::promise<int> p;