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
This commit is contained in:
Roman
2018-02-12 09:10:19 -08:00
committed by Carl Lerche
parent 0b58bded7c
commit 35aeabd3ff
9 changed files with 166 additions and 149 deletions
+2 -85
View File
@@ -1,95 +1,12 @@
use std::{fmt, io};
use std::fmt;
use AsyncRead;
use codec::Decoder;
use framed::Fuse;
use futures::{Async, Poll, Stream, Sink, StartSend};
use bytes::BytesMut;
/// Decoding of frames via buffers.
///
/// This trait is used when constructing an instance of `Framed` or
/// `FramedRead`. An implementation of `Decoder` takes a byte stream that has
/// already been buffered in `src` and decodes the data into a stream of
/// `Self::Item` frames.
///
/// Implementations are able to track state on `self`, which enables
/// implementing stateful streaming parsers. In many cases, though, this type
/// will simply be a unit struct (e.g. `struct HttpDecoder`).
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`.
///
/// `From<io::Error>` is required in the interest of making `Error` suitable
/// for returning directly from a `FramedRead`, and to enable the default
/// implementation of `decode_eof` to yield an `io::Error` when the decoder
/// fails to consume all available data.
///
/// Note that implementors of this trait can simply indicate `type Error =
/// io::Error` to use I/O errors as this type.
type Error: From<io::Error>;
/// Attempts to decode a frame from the provided buffer of bytes.
///
/// This method is called by `FramedRead` whenever bytes are ready to be
/// parsed. The provided buffer of bytes is what's been read so far, and
/// this instance of `Decode` can determine whether an entire frame is in
/// the buffer and is ready to be returned.
///
/// If an entire frame is available, then this instance will remove those
/// bytes from the buffer provided and return them as a decoded
/// frame. Note that removing bytes from the provided buffer doesn't always
/// necessarily copy the bytes, so this should be an efficient operation in
/// most circumstances.
///
/// If the bytes look valid, but a frame isn't fully available yet, then
/// `Ok(None)` is returned. This indicates to the `Framed` instance that
/// it needs to read some more bytes before calling this method again.
///
/// Note that the bytes provided may be empty. If a previous call to
/// `decode` consumed all the bytes in the buffer then `decode` will be
/// called again until it returns `None`, indicating that more bytes need to
/// be read.
///
/// Finally, if the bytes in the buffer are malformed then an error is
/// returned indicating why. This informs `Framed` that the stream is now
/// corrupt and should be terminated.
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.
///
/// Note that the `buf` argument may be empty. If a previous call to
/// `decode_eof` consumed all the bytes in the buffer, `decode_eof` will be
/// called again until it returns `None`, indicating that there are no more
/// frames to yield. This behavior enables returning finalization frames
/// that may not be based on inbound data.
fn decode_eof(&mut self, buf: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
match try!(self.decode(buf)) {
Some(frame) => Ok(Some(frame)),
None => {
if buf.is_empty() {
Ok(None)
} else {
Err(io::Error::new(io::ErrorKind::Other,
"bytes remaining on stream").into())
}
}
}
}
}
/// A `Stream` of messages decoded from an `AsyncRead`.
pub struct FramedRead<T, D> {
inner: FramedRead2<Fuse<T, D>>,