From ad4867c53d0cf7c5e683b321efed6de47d85f1f4 Mon Sep 17 00:00:00 2001
From: Stanislav Ravas <ravas@tind.sk>
Date: Mon, 6 May 2024 23:59:52 +0200
Subject: [PATCH] feat: implement embedded-io and embedded-io-async traits

Allows much better interoperatibility with other embedded rust projects,
which by now usually have support for embedded-io traits.
---
 Cargo.toml       |  7 ++++-
 src/eio.rs       | 77 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/eio_async.rs | 13 ++++++++
 src/lib.rs       |  4 +++
 4 files changed, 100 insertions(+), 1 deletion(-)
 create mode 100644 src/eio.rs
 create mode 100644 src/eio_async.rs

diff --git a/Cargo.toml b/Cargo.toml
index 1cc635dfb..e365a2512 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,7 +15,9 @@ bitflags = "1"
 cty = "0.2.1"
 delog = "0.1.0"
 generic-array = "0.14"
-heapless = "0.7"
+heapless = "0.8"
+embedded-io = { version = "0.6.1", optional = true }
+embedded-io-async = { version = "0.6.1", optional = true }
 
 [dependencies.cstr_core]
 default-features = false
@@ -44,6 +46,9 @@ ll-assertions = ["littlefs2-sys/assertions"]
 # enable trace in backend C code
 ll-trace = ["littlefs2-sys/trace"]
 c-stubs = []
+eio = ["dep:embedded-io"]
+eio-async = ["eio", "dep:embedded-io-async"]
+
 
 log-all = []
 log-none = []
diff --git a/src/eio.rs b/src/eio.rs
new file mode 100644
index 000000000..ab9a2c122
--- /dev/null
+++ b/src/eio.rs
@@ -0,0 +1,77 @@
+use crate::io;
+
+impl embedded_io::Error for io::Error {
+    fn kind(&self) -> embedded_io::ErrorKind {
+        match self {
+            io::Error::Success
+            | io::Error::Io
+            | io::Error::Corruption
+            | io::Error::PathNotDir
+            | io::Error::PathIsDir
+            | io::Error::DirNotEmpty
+            | io::Error::FileTooBig
+            | io::Error::NoSpace
+            | io::Error::NoAttribute
+            | io::Error::Unknown(_) => embedded_io::ErrorKind::Other,
+            io::Error::EntryAlreadyExisted => embedded_io::ErrorKind::AlreadyExists,
+            io::Error::NoSuchEntry => embedded_io::ErrorKind::NotFound,
+            io::Error::BadFileDescriptor | io::Error::Invalid | io::Error::FilenameTooLong => {
+                embedded_io::ErrorKind::InvalidInput
+            }
+            io::Error::NoMemory => embedded_io::ErrorKind::OutOfMemory,
+        }
+    }
+}
+
+pub struct Reader<'a, T: io::Read>(pub(crate) &'a T);
+
+impl<'a, T: io::Read> Reader<'a, T> {
+    pub fn new(read: &'a T) -> Self {
+        Self(read)
+    }
+}
+
+impl<'a, T: io::Read> embedded_io::ErrorType for Reader<'a, T> {
+    type Error = io::Error;
+}
+
+impl<'a, T: io::Read> embedded_io::Read for Reader<'a, T> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
+        self.0.read(buf)
+    }
+
+    fn read_exact(
+        &mut self,
+        buf: &mut [u8],
+    ) -> Result<(), embedded_io::ReadExactError<Self::Error>> {
+        self.0
+            .read_exact(buf)
+            .map_err(|e| embedded_io::ReadExactError::Other(e))
+    }
+}
+
+pub struct Writer<'a, T: io::Write>(pub(crate) &'a T);
+
+impl<'a, T: io::Write> Writer<'a, T> {
+    pub fn new(write: &'a T) -> Self {
+        Self(write)
+    }
+}
+
+impl<'a, T: io::Write> embedded_io::ErrorType for Writer<'a, T> {
+    type Error = io::Error;
+}
+
+impl<'a, T: io::Write> embedded_io::Write for Writer<'a, T> {
+    fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
+        self.0.write(buf)
+    }
+
+    fn flush(&mut self) -> Result<(), Self::Error> {
+        self.0.flush()
+    }
+
+    fn write_all(&mut self, buf: &[u8]) -> Result<(), Self::Error> {
+        self.0.write_all(buf)
+    }
+}
diff --git a/src/eio_async.rs b/src/eio_async.rs
new file mode 100644
index 000000000..db672b47e
--- /dev/null
+++ b/src/eio_async.rs
@@ -0,0 +1,13 @@
+use crate::io;
+
+impl<'a, T: io::Read> embedded_io_async::Read for super::eio::Reader<'a, T> {
+    async fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
+        self.0.read(buf)
+    }
+}
+
+impl<'a, T: io::Write> embedded_io_async::Write for super::eio::Writer<'a, T> {
+    async fn write(&mut self, buf: &[u8]) -> Result<usize, Self::Error> {
+        self.0.write(buf)
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index a7a78e2b5..12a33bc39 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -141,6 +141,10 @@ mod c_stubs;
 
 pub mod consts;
 pub mod driver;
+#[cfg(feature = "eio")]
+pub mod eio;
+#[cfg(feature = "eio-async")]
+pub mod eio_async;
 pub mod fs;
 pub mod io;
 pub mod object_safe;