1 files changed, 86 insertions, 0 deletions
diff --git a/tokio/src/sync/mpsc/error.rs b/tokio/src/sync/mpsc/error.rs
new file mode 100644
index 00000000..6238f854
--- /dev/null
+++ b/tokio/src/sync/mpsc/error.rs
@@ -0,0 +1,86 @@
+//! Channel error types
+
+use std::error::Error;
+use std::fmt;
+
+/// Error returned by the `Sender`.
+#[derive(Debug)]
+pub struct SendError<T>(pub T);
+
+impl<T> fmt::Display for SendError<T> {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(fmt, "channel closed")
+    }
+}
+
+impl<T: fmt::Debug> ::std::error::Error for SendError<T> {}
+
+// ===== TrySendError =====
+
+/// This enumeration is the list of the possible error outcomes for the
+/// [try_send](super::Sender::try_send) method.
+#[derive(Debug)]
+pub enum TrySendError<T> {
+    /// The data could not be sent on the channel because the channel is
+    /// currently full and sending would require blocking.
+    Full(T),
+
+    /// The receive half of the channel was explicitly closed or has been
+    /// dropped.
+    Closed(T),
+}
+
+impl<T: fmt::Debug> Error for TrySendError<T> {}
+
+impl<T> fmt::Display for TrySendError<T> {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(
+            fmt,
+            "{}",
+            match self {
+                TrySendError::Full(..) => "no available capacity",
+                TrySendError::Closed(..) => "channel closed",
+            }
+        )
+    }
+}
+
+impl<T> From<SendError<T>> for TrySendError<T> {
+    fn from(src: SendError<T>) -> TrySendError<T> {
+        TrySendError::Closed(src.0)
+    }
+}
+
+// ===== RecvError =====
+
+/// Error returned by `Receiver`.
+#[derive(Debug)]
+pub struct RecvError(());
+
+impl fmt::Display for RecvError {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(fmt, "channel closed")
+    }
+}
+
+impl Error for RecvError {}
+
+// ===== ClosedError =====
+
+/// Erorr returned by [`Sender::poll_ready`](super::Sender::poll_ready)].
+#[derive(Debug)]
+pub struct ClosedError(());
+
+impl ClosedError {
+    pub(crate) fn new() -> ClosedError {
+        ClosedError(())
+    }
+}
+
+impl fmt::Display for ClosedError {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(fmt, "channel closed")
+    }
+}
+
+impl Error for ClosedError {}