io: Fix FromStd::read_exact by mapping std::io::ErrorKind::UnexpectedEof to ReadExactError::UnexpectedEof

Author: Conaclos

embedded-io-adapters/Cargo.toml

@@ -7,10 +7,7 @@ description = "Adapters between the `embedded-io` traits and other I/O traits"
 repository = "https://github.com/rust-embedded/embedded-hal"
 readme = "README.md"
 license = "MIT OR Apache-2.0"
-categories = [
-    "embedded",
-    "no-std",
-]
+categories = ["embedded", "no-std"]
 
 [features]
 std = ["embedded-io/std"]

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> {