bmrng 0.5.2

async MPSC request-response channel for Tokio
Documentation 
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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166

use std::error::Error;
use std::fmt;
use tokio::sync::mpsc::error::SendError as MpscSendError;
use tokio::sync::oneshot;

/// Error thrown when a [`RequestSender::send()`](crate::RequestSender::send()) or [`UnboundedRequestSender::send()`](crate::unbounded::UnboundedRequestSender::send())
/// call fails because the channel is closed
#[derive(Debug, PartialEq)]
pub struct SendError<T>(pub T);

impl<T> From<SendError<T>> for MpscSendError<T> {
    fn from(err: SendError<T>) -> Self {
        Self(err.0)
    }
}

impl<T> From<MpscSendError<T>> for SendError<T> {
    fn from(err: MpscSendError<T>) -> Self {
        Self(err.0)
    }
}

impl<T> fmt::Display for SendError<T> {
    #[cfg(not(tarpaulin_include))]
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(fmt, "channel closed")
    }
}

impl<T> Error for SendError<T> where T: fmt::Debug {}

/// Errors that can occur when a [`RequestReceiver`](crate::RequestReceiver)
/// or [`UnboundedReceiver`](crate::unbounded::UnboundedRequestReceiver) handles a request
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum RequestError<T> {
    /// Error occurring when the channel from [`RequestSender`](crate::RequestSender) to [`RequestReceiver`](crate::RequestReceiver) is closed
    RecvError,
    /// Error occurring when the Responder fails to send a response before the timeout
    RecvTimeoutError,
    /// Error occurring when the channel from [`RequestReceiver`](crate::RequestReceiver) to [RequestSender](crate::RequestSender) is closed
    SendError(T),
}

/// Errors that can occur when a [`ResponseReceiver`](crate::ResponseReceiver) is
// waiting for a response
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum ReceiveError {
    /// Error occurring when the channel from [`RequestSender`](crate::RequestSender) to [`RequestReceiver`](crate::RequestReceiver) is closed
    RecvError,
    /// Error occurring when the Responder fails to send a response before the timeout
    TimeoutError,
}

impl<T> From<SendError<T>> for RequestError<T> {
    fn from(err: SendError<T>) -> RequestError<T> {
        RequestError::SendError(err.0)
    }
}

impl<T> From<RespondError<T>> for RequestError<T> {
    fn from(err: RespondError<T>) -> RequestError<T> {
        RequestError::SendError(err.0)
    }
}

impl<T> From<ReceiveError> for RequestError<T> {
    fn from(err: ReceiveError) -> RequestError<T> {
        match err {
            ReceiveError::RecvError => RequestError::RecvError,
            ReceiveError::TimeoutError => RequestError::RecvTimeoutError,
        }
    }
}

impl From<oneshot::error::RecvError> for ReceiveError {
    fn from(_err: oneshot::error::RecvError) -> ReceiveError {
        ReceiveError::RecvError
    }
}

impl<T> fmt::Display for RequestError<T> {
    #[cfg(not(tarpaulin_include))]
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            fmt,
            "{}",
            match self {
                RequestError::RecvError => "request channel closed",
                RequestError::RecvTimeoutError => "request timed out",
                RequestError::SendError(..) => "channel closed",
            }
        )
    }
}

impl<T> Error for RequestError<T> where T: fmt::Debug {}

impl fmt::Display for ReceiveError {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            fmt,
            "{}",
            match self {
                ReceiveError::RecvError => "receive channel closed",
                ReceiveError::TimeoutError => "request timed out",
            }
        )
    }
}

impl Error for ReceiveError {}

/// Error thrown when a Responder fails to respond.
/// The channel was closed by the receiver, the original request sender
#[derive(Debug, Copy, Clone, PartialEq)]
pub struct RespondError<T>(pub T);

impl<T> fmt::Display for RespondError<T> {
    #[cfg(not(tarpaulin_include))]
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(fmt, "sender closed the response channel",)
    }
}

impl<T> Error for RespondError<T> where T: fmt::Debug {}

#[cfg(test)]
pub mod tests {
    pub use super::*;

    #[test]
    fn send_err_into_mpsc_send_error() {
        let err = SendError(42);
        let m_err: MpscSendError<u32> = err.into();
        assert_eq!(m_err.0, 42);
    }

    #[test]
    fn mpsc_send_err_into_send_error() {
        let err = MpscSendError(42);
        let m_err: SendError<u32> = err.into();
        assert_eq!(m_err.0, 42);
    }

    #[test]
    fn send_error_into_request_error() {
        let err = SendError(42);
        let r_err: RequestError<i32> = err.into();
        assert_eq!(r_err, RequestError::SendError(42));
    }

    #[test]
    fn reply_error_to_request_error() {
        let err = RespondError(21);
        let q_err: RequestError<i32> = err.into();
        assert_eq!(q_err, RequestError::SendError(21));
    }

    #[test]
    fn receive_error_display() {
        let err = ReceiveError::RecvError;
        assert_eq!("receive channel closed", err.to_string());
        let err = ReceiveError::TimeoutError;
        assert_eq!("request timed out", err.to_string());
    }
}