1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146

//! 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 {}

// ===== TryRecvError =====

/// This enumeration is the list of the possible reasons that try_recv
/// could not return data when called.
#[derive(Debug, PartialEq)]
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 been closed, and there will
    /// never be any more data received on it.
    Closed,
}

impl fmt::Display for TryRecvError {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            fmt,
            "{}",
            match self {
                TryRecvError::Empty => "channel empty",
                TryRecvError::Closed => "channel closed",
            }
        )
    }
}

impl Error for TryRecvError {}

// ===== ClosedError =====

/// Error 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 {}

cfg_time! {
    // ===== SendTimeoutError =====

    #[derive(Debug)]
    /// 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> Error for SendTimeoutError<T> {}

    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",
                }
            )
        }
    }
}