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//! Channel error types.
use std::error::Error;
use std::fmt;
/// Error returned by the `Sender`.
#[derive(PartialEq, Eq, Clone, Copy)]
pub struct SendError<T>(pub T);
impl<T> fmt::Debug for SendError<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("SendError").finish_non_exhaustive()
}
}
impl<T> fmt::Display for SendError<T> {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(fmt, "channel closed")
}
}
impl<T> 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(PartialEq, Eq, Clone, Copy)]
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 for TrySendError<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match *self {
TrySendError::Full(..) => "Full(..)".fmt(f),
TrySendError::Closed(..) => "Closed(..)".fmt(f),
}
}
}
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> Error for TrySendError<T> {}
impl<T> From<SendError<T>> for TrySendError<T> {
fn from(src: SendError<T>) -> TrySendError<T> {
TrySendError::Closed(src.0)
}
}
// ===== TryRecvError =====
/// Error returned by `try_recv`.
#[derive(PartialEq, Eq, Clone, Copy, Debug)]
pub enum TryRecvError {
/// This **channel** is currently empty, but the **Sender**(s) have not yet
/// disconnected, so data may yet become available.
Empty,
/// The **channel**'s sending half has become disconnected, and there will
/// never be any more data received on it.
Disconnected,
}
impl fmt::Display for TryRecvError {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
match *self {
TryRecvError::Empty => "receiving on an empty channel".fmt(fmt),
TryRecvError::Disconnected => "receiving on a closed channel".fmt(fmt),
}
}
}
impl Error for TryRecvError {}
// ===== RecvError =====
/// Error returned by `Receiver`.
#[derive(Debug, Clone)]
#[doc(hidden)]
#[deprecated(note = "This type is unused because recv returns an Option.")]
pub struct RecvError(());
#[allow(deprecated)]
impl fmt::Display for RecvError {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(fmt, "channel closed")
}
}
#[allow(deprecated)]
impl Error for RecvError {}
cfg_time! {
// ===== SendTimeoutError =====
#[derive(PartialEq, Eq, Clone, Copy)]
/// Error returned by [`Sender::send_timeout`](super::Sender::send_timeout)].
pub enum SendTimeoutError<T> {
/// The data could not be sent on the channel because the channel is
/// full, and the timeout to send has elapsed.
Timeout(T),
/// The receive half of the channel was explicitly closed or has been
/// dropped.
Closed(T),
}
impl<T> fmt::Debug for SendTimeoutError<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match *self {
SendTimeoutError::Timeout(..) => "Timeout(..)".fmt(f),
SendTimeoutError::Closed(..) => "Closed(..)".fmt(f),
}
}
}
impl<T> fmt::Display for SendTimeoutError<T> {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
fmt,
"{}",
match self {
SendTimeoutError::Timeout(..) => "timed out waiting on send operation",
SendTimeoutError::Closed(..) => "channel closed",
}
)
}
}
impl<T> Error for SendTimeoutError<T> {}
}