nmode's Git Repositories - signal-cli/blob - client/src/transports/stream_codec.rs

   1 use bytes::BytesMut;
   2 use std::{io, str};
   3 use tokio_util::codec::{Decoder, Encoder};
   4
   5 type Separator = u8;
   6
   7 /// Stream codec for streaming protocols (ipc, tcp)
   8 #[derive(Debug, Default)]
   9 pub struct StreamCodec {
  10     incoming_separator: Separator,
  11     outgoing_separator: Separator,
  12 }
  13
  14 impl StreamCodec {
  15     /// Default codec with streaming input data. Input can be both enveloped and not.
  16     pub fn stream_incoming() -> Self {
  17         StreamCodec::new(b'\n', b'\n')
  18     }
  19
  20     /// New custom stream codec
  21     pub fn new(incoming_separator: Separator, outgoing_separator: Separator) -> Self {
  22         StreamCodec {
  23             incoming_separator,
  24             outgoing_separator,
  25         }
  26     }
  27 }
  28
  29 impl Decoder for StreamCodec {
  30     type Item = String;
  31     type Error = io::Error;
  32
  33     fn decode(&mut self, buf: &mut BytesMut) -> io::Result<Option<Self::Item>> {
  34         if let Some(i) = buf
  35             .as_ref()
  36             .iter()
  37             .position(|&b| b == self.incoming_separator)
  38         {
  39             let line = buf.split_to(i);
  40             let _ = buf.split_to(1);
  41
  42             match str::from_utf8(line.as_ref()) {
  43                 Ok(s) => Ok(Some(s.to_string())),
  44                 Err(_) => Err(io::Error::other("invalid UTF-8")),
  45             }
  46         } else {
  47             Ok(None)
  48         }
  49     }
  50 }
  51
  52 impl Encoder<String> for StreamCodec {
  53     type Error = io::Error;
  54
  55     fn encode(&mut self, msg: String, buf: &mut BytesMut) -> io::Result<()> {
  56         let mut payload = msg.into_bytes();
  57         payload.push(self.outgoing_separator);
  58         buf.extend_from_slice(&payload);
  59         Ok(())
  60     }
  61 }