From ac1a26b40f417e776de8ebd731f811134f97b3f9 Mon Sep 17 00:00:00 2001
From: Dario Nieuwenhuis <dirbaio@dirbaio.net>
Date: Wed, 3 Aug 2022 14:15:16 +0200
Subject: [PATCH] util/pipe: add embedded-io impls for Pipe, Reader, Writer.

---
 embassy-util/Cargo.toml  |   6 ++-
 embassy-util/src/lib.rs  |   1 -
 embassy-util/src/pipe.rs | 109 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 114 insertions(+), 2 deletions(-)

diff --git a/embassy-util/Cargo.toml b/embassy-util/Cargo.toml
index 32b796c0..ef5acc0f 100644
--- a/embassy-util/Cargo.toml
+++ b/embassy-util/Cargo.toml
@@ -6,11 +6,14 @@ edition = "2021"
 [package.metadata.embassy_docs]
 src_base = "https://github.com/embassy-rs/embassy/blob/embassy-util-v$VERSION/embassy-util/src/"
 src_base_git = "https://github.com/embassy-rs/embassy/blob/$COMMIT/embassy-util/src/"
-features = ["nightly", "defmt", "unstable-traits", "time", "time-tick-1mhz"]
+features = ["nightly"]
 flavors = [
     { name = "default", target = "x86_64-unknown-linux-gnu" },
 ]
 
+[features]
+nightly = ["embedded-io/async"]
+
 [dependencies]
 defmt = { version = "0.3", optional = true }
 log = { version = "0.4.14", optional = true }
@@ -20,6 +23,7 @@ atomic-polyfill = "0.1.5"
 critical-section = "0.2.5"
 heapless = "0.7.5"
 cfg-if = "1.0.0"
+embedded-io = "0.3.0"
 
 [dev-dependencies]
 futures-executor = { version = "0.3.17", features = [ "thread-pool" ] }
diff --git a/embassy-util/src/lib.rs b/embassy-util/src/lib.rs
index a65ebd51..110c7281 100644
--- a/embassy-util/src/lib.rs
+++ b/embassy-util/src/lib.rs
@@ -1,6 +1,5 @@
 #![cfg_attr(not(any(feature = "std", feature = "wasm")), no_std)]
 #![cfg_attr(feature = "nightly", feature(generic_associated_types, type_alias_impl_trait))]
-#![cfg_attr(all(feature = "nightly", target_arch = "xtensa"), feature(asm_experimental_arch))]
 #![allow(clippy::new_without_default)]
 #![doc = include_str!("../../README.md")]
 #![warn(missing_docs)]
diff --git a/embassy-util/src/pipe.rs b/embassy-util/src/pipe.rs
index e4f21732..c0a5d2f6 100644
--- a/embassy-util/src/pipe.rs
+++ b/embassy-util/src/pipe.rs
@@ -319,6 +319,115 @@ where
     }
 }
 
+#[cfg(feature = "nightly")]
+mod io_impls {
+    use core::convert::Infallible;
+
+    use futures_util::FutureExt;
+
+    use super::*;
+
+    impl<M: RawMutex, const N: usize> embedded_io::Io for Pipe<M, N> {
+        type Error = Infallible;
+    }
+
+    impl<M: RawMutex, const N: usize> embedded_io::asynch::Read for Pipe<M, N> {
+        type ReadFuture<'a> = impl Future<Output = Result<usize, Self::Error>>
+        where
+            Self: 'a;
+
+        fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> Self::ReadFuture<'a> {
+            Pipe::read(self, buf).map(Ok)
+        }
+    }
+
+    impl<M: RawMutex, const N: usize> embedded_io::asynch::Write for Pipe<M, N> {
+        type WriteFuture<'a> = impl Future<Output = Result<usize, Self::Error>>
+        where
+            Self: 'a;
+
+        fn write<'a>(&'a mut self, buf: &'a [u8]) -> Self::WriteFuture<'a> {
+            Pipe::write(self, buf).map(Ok)
+        }
+
+        type FlushFuture<'a> = impl Future<Output = Result<(), Self::Error>>
+        where
+            Self: 'a;
+
+        fn flush<'a>(&'a mut self) -> Self::FlushFuture<'a> {
+            futures_util::future::ready(Ok(()))
+        }
+    }
+
+    impl<M: RawMutex, const N: usize> embedded_io::Io for &Pipe<M, N> {
+        type Error = Infallible;
+    }
+
+    impl<M: RawMutex, const N: usize> embedded_io::asynch::Read for &Pipe<M, N> {
+        type ReadFuture<'a> = impl Future<Output = Result<usize, Self::Error>>
+        where
+            Self: 'a;
+
+        fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> Self::ReadFuture<'a> {
+            Pipe::read(self, buf).map(Ok)
+        }
+    }
+
+    impl<M: RawMutex, const N: usize> embedded_io::asynch::Write for &Pipe<M, N> {
+        type WriteFuture<'a> = impl Future<Output = Result<usize, Self::Error>>
+        where
+            Self: 'a;
+
+        fn write<'a>(&'a mut self, buf: &'a [u8]) -> Self::WriteFuture<'a> {
+            Pipe::write(self, buf).map(Ok)
+        }
+
+        type FlushFuture<'a> = impl Future<Output = Result<(), Self::Error>>
+        where
+            Self: 'a;
+
+        fn flush<'a>(&'a mut self) -> Self::FlushFuture<'a> {
+            futures_util::future::ready(Ok(()))
+        }
+    }
+
+    impl<M: RawMutex, const N: usize> embedded_io::Io for Reader<'_, M, N> {
+        type Error = Infallible;
+    }
+
+    impl<M: RawMutex, const N: usize> embedded_io::asynch::Read for Reader<'_, M, N> {
+        type ReadFuture<'a> = impl Future<Output = Result<usize, Self::Error>>
+        where
+            Self: 'a;
+
+        fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> Self::ReadFuture<'a> {
+            Reader::read(self, buf).map(Ok)
+        }
+    }
+
+    impl<M: RawMutex, const N: usize> embedded_io::Io for Writer<'_, M, N> {
+        type Error = Infallible;
+    }
+
+    impl<M: RawMutex, const N: usize> embedded_io::asynch::Write for Writer<'_, M, N> {
+        type WriteFuture<'a> = impl Future<Output = Result<usize, Self::Error>>
+        where
+            Self: 'a;
+
+        fn write<'a>(&'a mut self, buf: &'a [u8]) -> Self::WriteFuture<'a> {
+            Writer::write(self, buf).map(Ok)
+        }
+
+        type FlushFuture<'a> = impl Future<Output = Result<(), Self::Error>>
+        where
+            Self: 'a;
+
+        fn flush<'a>(&'a mut self) -> Self::FlushFuture<'a> {
+            futures_util::future::ready(Ok(()))
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use futures_executor::ThreadPool;