code.octet-stream.net Git - m17rt/blob - m17app/src/tnc.rs

   1 use std::io::{Read, Write};
   2
   3 /// A TNC that supports reading and writing M17 KISS messages.
   4 ///
   5 /// TNCs must be cloneable to support reading and writing from different threads,
   6 /// via a working implementation of try_clone(). We do not require `Clone` directly
   7 /// as this could not be fulfilled by `TcpStream`.
   8 pub trait Tnc: Read + Write + Sized + Send + 'static {
   9     /// Return a copy of this TNC.
  10     ///
  11     /// `M17App` will use this to create a second instance of the supplied TNC then use
  12     /// one of them for reading and one of them for writing, concurrently across two threads.
  13     ///
  14     /// Implementations do not need to worry about trying to make two simultaneous reads or
  15     /// two simultaneous writes do something sensible. `M17App` will not do this and it would
  16     /// probably produce garbled KISS messages anyway.
  17     fn try_clone(&mut self) -> Result<Self, TncError>;
  18
  19     /// Start I/O.
  20     fn start(&mut self) -> Result<(), TncError>;
  21
  22     /// Shut down I/O - it is assumed we cannot restart.
  23     fn close(&mut self) -> Result<(), TncError>;
  24 }
  25
  26 #[derive(Debug, PartialEq, Eq, Clone)]
  27 pub enum TncError {
  28     // TODO: Good error cases
  29     Unknown,
  30 }
  31
  32 impl Tnc for std::net::TcpStream {
  33     fn try_clone(&mut self) -> Result<Self, TncError> {
  34         std::net::TcpStream::try_clone(self).map_err(|_| TncError::Unknown)
  35     }
  36
  37     fn start(&mut self) -> Result<(), TncError> {
  38         // already started, hopefully we get onto reading the socket quickly
  39         Ok(())
  40     }
  41
  42     fn close(&mut self) -> Result<(), TncError> {
  43         self.shutdown(std::net::Shutdown::Both)
  44             .map_err(|_| TncError::Unknown)
  45     }
  46 }