1 files changed, 35 insertions, 0 deletions
diff --git a/third_party/rust/mio-0.6.23/src/io.rs b/third_party/rust/mio-0.6.23/src/io.rs
new file mode 100644
index 0000000000..275001387d
--- /dev/null
+++ b/third_party/rust/mio-0.6.23/src/io.rs
@@ -0,0 +1,35 @@
+// Re-export the io::Result / Error types for convenience
+pub use std::io::{Read, Write, Result, Error, ErrorKind};
+
+// TODO: Delete this
+/// A helper trait to provide the map_non_block function on Results.
+pub trait MapNonBlock<T> {
+    /// Maps a `Result<T>` to a `Result<Option<T>>` by converting
+    /// operation-would-block errors into `Ok(None)`.
+    fn map_non_block(self) -> Result<Option<T>>;
+}
+
+impl<T> MapNonBlock<T> for Result<T> {
+    fn map_non_block(self) -> Result<Option<T>> {
+        use std::io::ErrorKind::WouldBlock;
+
+        match self {
+            Ok(value) => Ok(Some(value)),
+            Err(err) => {
+                if let WouldBlock = err.kind() {
+                    Ok(None)
+                } else {
+                    Err(err)
+                }
+            }
+        }
+    }
+}
+
+#[cfg(feature = "with-deprecated")]
+pub mod deprecated {
+    /// Returns a std `WouldBlock` error without allocating
+    pub fn would_block() -> ::std::io::Error {
+        ::std::io::ErrorKind::WouldBlock.into()
+    }
+}