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
167
168

#[cfg(feature = "buf_recv")]
mod buffered_receiver;
#[cfg(feature = "buf_recv")]
pub use buffered_receiver::*;

use core::any::*;
use std::{error::Error, fmt::Display, sync::mpsc::{self, Sender, Receiver}};

/// An [mpsc::channel] that supports dynamic typing.
pub fn channel() -> (AnySender, AnyReceiver)
{
    let (tx, rx) = mpsc::channel();
    (AnySender(tx), AnyReceiver(rx))
}

/// Wraps an [mpsc::Sender] to support dynamic typing.
#[derive(Debug)]
pub struct AnySender(pub Sender<Box<dyn Any>>);

impl AnySender
{
    /// Wraps [mpsc::Sender::send].
    pub fn send<T: Any>(&self, t: T) -> Result<(), mpsc::SendError<Box<dyn Any>>>
    {
        self.0.send(Box::new(t))
    }
}

/// Wraps an [mpsc::Receiver] to support dynamic typing.
#[derive(Debug)]
pub struct AnyReceiver(pub Receiver<Box<dyn Any>>);

impl AnyReceiver
{
    /// Wraps [mpsc::Receiver::recv]. See [crate::AnyRecvError] for details on the 
    /// return value.
    pub fn recv<T: 'static>(&self) -> Result<T, AnyRecvError>
    {
        self.0
            .recv()
            .map_err(AnyRecvError::RecvError)
            .and_then(|r| match r.downcast()
            {
                Ok(r) => Ok(*r),
                Err(r) => Err(AnyRecvError::WrongType(r)),
            })
    }

    /// Wraps [mpsc::Receiver::recv_timeout]. See [crate::AnyRecvError] for 
    /// details on the return value.
    pub fn recv_timeout<T: 'static>(&self, timeout: std::time::Duration) -> Result<T, AnyRecvError>
    {
        self.0
            .recv_timeout(timeout)
            .map_err(AnyRecvError::RecvTimeoutError)
            .and_then(|r| match r.downcast()
            {
                Ok(r) => Ok(*r),
                Err(r) => Err(AnyRecvError::WrongType(r)),
            })
    }

    /// Wraps [mpsc::Receiver::try_recv]. See [crate::AnyRecvError] for 
    /// details on the return value.
    pub fn try_recv<T: 'static>(&self) -> Result<T, AnyRecvError>
    {
        self.0
            .try_recv()
            .map_err(AnyRecvError::TryRecvError)
            .and_then(|r| match r.downcast()
            {
                Ok(r) => Ok(*r),
                Err(r) => Err(AnyRecvError::WrongType(r)),
            })
    }
}

/// Error type for receievers. If an [mpsc] error occurs, it will be wrapped
/// by an appropriate wrapper variant. If receiver is supplied an incorrect type, 
/// a [AnyRecvError::WrongType(Box<dyn Any>)] will be returned containing the result 
/// that did not successfully downcast. If buffered receiver is supplied an 
/// incorrect type, a [BufRecvError::WrongType(TypeId)] will be returned and the 
/// result will be stored in a buffer. If [BufferedReceiver::recv_buf] is called
/// with an empty buffer, EmptyBuffer will be returned
#[derive(Debug)]
pub enum AnyRecvError
{
    RecvError(mpsc::RecvError),
    RecvTimeoutError(mpsc::RecvTimeoutError),
    TryRecvError(mpsc::TryRecvError),
    WrongType(Box<dyn Any>),
    #[cfg(feature = "buf_recv")]
    BufRecvError(TypeId),
    #[cfg(feature = "buf_recv")]
    EmptyBuffer
}

impl Display for AnyRecvError
{
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result 
    {
        match self
        {
            AnyRecvError::RecvError(err) => err.fmt(f), 
            AnyRecvError::RecvTimeoutError(err) => err.fmt(f),
            AnyRecvError::TryRecvError(err) => err.fmt(f),
            AnyRecvError::WrongType(_) => write!(f, "Received wrong type"),
            AnyRecvError::BufRecvError(type_id) => write!(f, "Received wrong type: {:?}", type_id),
            AnyRecvError::EmptyBuffer => write!(f, "Buffer is empty"),
        }
    }
}
impl Error for AnyRecvError {}

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

    #[test]
    pub fn any_channel_test()
    {
        let (atx, arx) = channel();
        atx.send(67 as i32).unwrap();
        println!("{:?}", arx.recv::<u32>());
    }
    
    #[test]
    pub fn any_channel_test_1()
    {
        let (atx, arx) = channel();
        atx.send(88 as i32).unwrap();
        println!("{:?}", arx.recv::<i32>());
    }
    
    #[test]
    pub fn any_channel_test_2()
    {
        let to_send = 55.7f32;
        let (atx, arx) = channel();
        atx.send(to_send).unwrap();
        println!("{:?}", arx.recv::<f32>());
    }

    #[test]
    pub fn readme_test()
    {
        use buffered_receiver::*;
        fn receive_handler<T: std::fmt::Debug + 'static>(rx: &mut BufferedReceiver)
        {
            match rx.recv::<T>()
            {
                Ok(result) => println!("{:?}", result),
                Err(AnyRecvError::BufRecvError(type_id)) => println!("Type with id {:?} added to buffer", type_id),
                Err(e) => eprintln!("{:?}", e)
            }
        }
        
        let (tx, mut rx) = crate::buffered_channel();
        
        tx.send(55.7f32).unwrap();
        tx.send(String::from("example")).unwrap();
        
        receive_handler::<f32>(&mut rx);
        receive_handler::<f32>(&mut rx);
        receive_handler::<String>(&mut rx);
    }
}