io: Fix Read::read_exact std adapter

Author: Conaclos

embedded-io-adapters/src/std.rs

@@ -1,6 +1,6 @@
 //! Adapters to/from `std::io` traits.
 
-use embedded_io::Error as _;
+use embedded_io::{Error as _, ReadExactError};
 
 /// Adapter from `std::io` traits.
 #[derive(Clone)]
@@ -40,6 +40,16 @@ impl<T: std::io::Read + ?Sized> embedded_io::Read for FromStd<T> {
     fn read(&mut self, buf: &mut [u8]) -> Result<usize, Self::Error> {
         self.inner.read(buf)
     }
+
+    fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), ReadExactError<Self::Error>> {
+        match self.inner.read_exact(buf) {
+            Ok(()) => Ok(()),
+            Err(error) if error.kind() == std::io::ErrorKind::UnexpectedEof => {
+                Err(embedded_io::ReadExactError::UnexpectedEof)
+            }
+            Err(error) => Err(error.into()),
+        }
+    }
 }
 
 impl<T: std::io::BufRead + ?Sized> embedded_io::BufRead for FromStd<T> {
@@ -105,6 +115,17 @@ impl<T: embedded_io::Read + ?Sized> std::io::Read for ToStd<T> {
     fn read(&mut self, buf: &mut [u8]) -> Result<usize, std::io::Error> {
         self.inner.read(buf).map_err(to_std_error)
     }
+
+    fn read_exact(&mut self, buf: &mut [u8]) -> std::io::Result<()> {
+        match self.inner.read_exact(buf) {
+            Ok(()) => Ok(()),
+            Err(e @ ReadExactError::UnexpectedEof) => Err(std::io::Error::new(
+                std::io::ErrorKind::UnexpectedEof,
+                format!("{e:?}"),
+            )),
+            Err(ReadExactError::Other(e)) => Err(to_std_error(e)),
+        }
+    }
 }
 
 impl<T: embedded_io::Write + ?Sized> std::io::Write for ToStd<T> {