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use bytes::BytesMut; /// Decoding of frames via buffers. pub trait Decoder { /// The type of decoded frames. type Item; /// The type of unrecoverable frame decoding errors. /// /// If an individual message is ill-formed but can be ignored without /// interfering with the processing of future messages, it may be more /// useful to report the failure as an `Item`. type Error: std::fmt::Debug; /// Attempts to decode a frame from the provided buffer of bytes. fn decode(&mut self, src: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error>; /// A default method available to be called when there are no more bytes /// available to be read from the underlying I/O. /// /// This method defaults to calling `decode` and returns an error if /// `Ok(None)` is returned while there is unconsumed data in `buf`. /// Typically this doesn't need to be implemented unless the framing /// protocol differs near the end of the stream. fn decode_eof( &mut self, buf: &mut BytesMut, ) -> Result<Option<Self::Item>, Self::Error> { match self.decode(buf)? { Some(frame) => Ok(Some(frame)), None => Ok(None), } } }