async_unsync/
error.rs

Help
1//! Error types for fallible channel operations.
2
3use core::fmt;
4
5use crate::semaphore::TryAcquireError;
6
7/// An error which can occur when sending a value through a closed channel.
8#[derive(Clone, Copy, PartialEq, Eq)]
9pub struct SendError<T>(pub T);
10
11impl<T> fmt::Debug for SendError<T> {
12    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
13        f.debug_struct("SendError").finish_non_exhaustive()
14    }
15}
16
17impl<T> fmt::Display for SendError<T> {
18    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
19        f.write_str("failed to send value, channel closed")
20    }
21}
22
23#[cfg(feature = "std")]
24impl<T> std::error::Error for SendError<T> {}
25
26/// An error which can occur when receiving on a closed or empty channel.
27#[derive(Clone, Copy, Debug, PartialEq, Eq)]
28pub enum TryRecvError {
29    /// This **channel** is currently empty, but the **Sender**(s) have not yet
30    /// disconnected, so data may yet become available.
31    Empty,
32    /// The **channel**’s sending half has become disconnected, and there will
33    /// never be any more data received on it.
34    Disconnected,
35}
36
37impl TryRecvError {
38    /// Returns `true` if the error is [`TryRecvError::Empty`].
39    pub fn is_empty(self) -> bool {
40        matches!(self, Self::Empty)
41    }
42
43    /// Returns `true` if the error is [`TryRecvError::Disconnected`].
44    pub fn is_disconnected(self) -> bool {
45        matches!(self, Self::Disconnected)
46    }
47}
48
49impl fmt::Display for TryRecvError {
50    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
51        match self {
52            Self::Empty => f.write_str("channel is empty"),
53            Self::Disconnected => f.write_str("channel is closed"),
54        }
55    }
56}
57
58#[cfg(feature = "std")]
59impl std::error::Error for TryRecvError {}
60
61/// An error which can occur when sending a value through a closed or full
62/// channel.
63#[derive(Clone, Copy, PartialEq, Eq)]
64pub enum TrySendError<T> {
65    /// This **channel** is currently full.
66    Full(T),
67    /// This **channel**'s receiving half has been explicitly disconnected or
68    /// dropped and the channel was closed.
69    Closed(T),
70}
71
72impl<T> TrySendError<T> {
73    /// Returns `true` if the error is [`TrySendError::Full`].
74    pub fn is_full(&self) -> bool {
75        matches!(self, Self::Full(_))
76    }
77
78    /// Returns `true` if the error is [`TrySendError::Closed`].
79    pub fn is_closed(&self) -> bool {
80        matches!(self, Self::Closed(_))
81    }
82
83    #[cfg(feature = "alloc")]
84    pub(crate) fn set<U>(self, value: U) -> TrySendError<U> {
85        match self {
86            Self::Full(_) => TrySendError::Full(value),
87            Self::Closed(_) => TrySendError::Closed(value),
88        }
89    }
90}
91
92impl<T> From<SendError<T>> for TrySendError<T> {
93    fn from(err: SendError<T>) -> Self {
94        Self::Closed(err.0)
95    }
96}
97
98impl<T> From<(TryAcquireError, T)> for TrySendError<T> {
99    fn from((err, elem): (TryAcquireError, T)) -> Self {
100        match err {
101            TryAcquireError::Closed => Self::Closed(elem),
102            TryAcquireError::NoPermits => Self::Full(elem),
103        }
104    }
105}
106
107impl<T> fmt::Debug for TrySendError<T> {
108    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
109        let mut dbg = f.debug_struct("TrySendError");
110        match self {
111            Self::Full(_) => dbg.field("full", &true).finish_non_exhaustive(),
112            Self::Closed(_) => dbg.field("closed", &true).finish_non_exhaustive(),
113        }
114    }
115}
116
117impl<T> fmt::Display for TrySendError<T> {
118    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
119        match self {
120            Self::Full(_) => f.write_str("failed to send value, channel full"),
121            Self::Closed(_) => f.write_str("failed to send value, channel closed"),
122        }
123    }
124}
125
126#[cfg(feature = "std")]
127impl<T> std::error::Error for TrySendError<T> {}
async_unsync/error.rs

async_unsync/
error.rs
