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Split codec code (#128)
* move src/codec.rs -> src/codec/mod.rs
* Move traits Encoder and Decoder from src/framed_{read|write}.rs into src/codec/{encoder,decoder}.rs
* Move LinesCodec and BytesCodec from src/codecs.rs into src/codec/{lines,bytes}_codec.rs
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@@ -1,95 +1,12 @@
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use std::{fmt, io};
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use std::fmt;
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use AsyncRead;
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use codec::Decoder;
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use framed::Fuse;
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use futures::{Async, Poll, Stream, Sink, StartSend};
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use bytes::BytesMut;
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/// Decoding of frames via buffers.
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///
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/// This trait is used when constructing an instance of `Framed` or
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/// `FramedRead`. An implementation of `Decoder` takes a byte stream that has
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/// already been buffered in `src` and decodes the data into a stream of
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/// `Self::Item` frames.
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///
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/// Implementations are able to track state on `self`, which enables
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/// implementing stateful streaming parsers. In many cases, though, this type
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/// will simply be a unit struct (e.g. `struct HttpDecoder`).
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pub trait Decoder {
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/// The type of decoded frames.
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type Item;
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/// The type of unrecoverable frame decoding errors.
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///
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/// If an individual message is ill-formed but can be ignored without
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/// interfering with the processing of future messages, it may be more
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/// useful to report the failure as an `Item`.
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///
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/// `From<io::Error>` is required in the interest of making `Error` suitable
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/// for returning directly from a `FramedRead`, and to enable the default
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/// implementation of `decode_eof` to yield an `io::Error` when the decoder
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/// fails to consume all available data.
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///
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/// Note that implementors of this trait can simply indicate `type Error =
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/// io::Error` to use I/O errors as this type.
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type Error: From<io::Error>;
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/// Attempts to decode a frame from the provided buffer of bytes.
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///
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/// This method is called by `FramedRead` whenever bytes are ready to be
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/// parsed. The provided buffer of bytes is what's been read so far, and
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/// this instance of `Decode` can determine whether an entire frame is in
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/// the buffer and is ready to be returned.
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///
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/// If an entire frame is available, then this instance will remove those
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/// bytes from the buffer provided and return them as a decoded
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/// frame. Note that removing bytes from the provided buffer doesn't always
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/// necessarily copy the bytes, so this should be an efficient operation in
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/// most circumstances.
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///
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/// If the bytes look valid, but a frame isn't fully available yet, then
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/// `Ok(None)` is returned. This indicates to the `Framed` instance that
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/// it needs to read some more bytes before calling this method again.
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///
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/// Note that the bytes provided may be empty. If a previous call to
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/// `decode` consumed all the bytes in the buffer then `decode` will be
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/// called again until it returns `None`, indicating that more bytes need to
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/// be read.
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///
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/// Finally, if the bytes in the buffer are malformed then an error is
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/// returned indicating why. This informs `Framed` that the stream is now
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/// corrupt and should be terminated.
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fn decode(&mut self, src: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error>;
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/// A default method available to be called when there are no more bytes
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/// available to be read from the underlying I/O.
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///
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/// This method defaults to calling `decode` and returns an error if
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/// `Ok(None)` is returned while there is unconsumed data in `buf`.
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/// Typically this doesn't need to be implemented unless the framing
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/// protocol differs near the end of the stream.
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///
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/// Note that the `buf` argument may be empty. If a previous call to
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/// `decode_eof` consumed all the bytes in the buffer, `decode_eof` will be
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/// called again until it returns `None`, indicating that there are no more
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/// frames to yield. This behavior enables returning finalization frames
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/// that may not be based on inbound data.
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fn decode_eof(&mut self, buf: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
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match try!(self.decode(buf)) {
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Some(frame) => Ok(Some(frame)),
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None => {
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if buf.is_empty() {
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Ok(None)
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} else {
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Err(io::Error::new(io::ErrorKind::Other,
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"bytes remaining on stream").into())
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}
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}
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}
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}
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}
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/// A `Stream` of messages decoded from an `AsyncRead`.
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pub struct FramedRead<T, D> {
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inner: FramedRead2<Fuse<T, D>>,
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