From caf7ac27916a1afc0cad72f4b6ac21c8404faf70 Mon Sep 17 00:00:00 2001
From: Vegard Storheil Eriksen <zyp@jvnv.net>
Date: Sat, 10 Sep 2022 17:11:24 +0200
Subject: async: Add source/sink concepts.

---
 async/concepts.h | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 async/concepts.h

diff --git a/async/concepts.h b/async/concepts.h
new file mode 100644
index 0000000..41f878a
--- /dev/null
+++ b/async/concepts.h
@@ -0,0 +1,42 @@
+#pragma once
+
+#include <concepts>
+#include <cstdint>
+#include <span>
+
+template <typename T, typename U = void>
+concept async_awaitable = requires(T a)
+{
+    // TODO: await_ready and await_suspend
+    { a.await_resume() } -> std::same_as<U>;
+};
+
+template <typename T, typename U>
+concept async_source = requires(T a)
+{
+    { a.async_get() } -> async_awaitable<U>;
+};
+
+template <typename T, typename U>
+concept async_sink = requires(T a, U v)
+{
+    { a.async_put(v) } -> async_awaitable<>;
+};
+
+template <typename T>
+concept async_byte_source = async_source<T, uint8_t>;
+
+template <typename T>
+concept async_byte_sink = async_sink<T, uint8_t>;
+
+template <typename T>
+concept async_packet_source = requires(T a, std::span<uint8_t> buf)
+{
+    { a.async_read(buf) } -> async_awaitable<std::span<uint8_t>>;
+};
+
+template <typename T>
+concept async_packet_sink = requires(T a, std::span<uint8_t> buf)
+{
+    { a.async_write(buf) } -> async_awaitable<>;
+};
-- 
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