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use super::framed_read::{framed_read_2, FramedRead2};
use super::framed_write::{framed_write_2, FramedWrite2};
use super::fuse::Fuse;
use super::{Decoder, Encoder};
use bytes::BytesMut;
use futures_sink::Sink;
use futures_util::io::{AsyncRead, AsyncWrite};
use futures_util::stream::{Stream, TryStreamExt};
use pin_project_lite::pin_project;
use std::marker::Unpin;
use std::ops::{Deref, DerefMut};
use std::pin::Pin;
use std::task::{Context, Poll};
pin_project! {
/// A unified `Stream` and `Sink` interface to an underlying I/O object,
/// using the `Encoder` and `Decoder` traits to encode and decode frames.
///
/// # Example
/// ```
/// use bytes::Bytes;
/// use futures::{SinkExt, TryStreamExt};
/// use futures::io::Cursor;
/// use asynchronous_codec::{BytesCodec, Framed};
///
/// # futures::executor::block_on(async move {
/// let cur = Cursor::new(vec![0u8; 12]);
/// let mut framed = Framed::new(cur, BytesCodec {});
///
/// // Send bytes to `buf` through the `BytesCodec`
/// let bytes = Bytes::from("Hello world!");
/// framed.send(bytes).await?;
///
/// // Drop down to the underlying I/O stream.
/// let cur = framed.into_inner();
/// assert_eq!(cur.get_ref(), b"Hello world!");
/// # Ok::<_, std::io::Error>(())
/// # }).unwrap();
/// ```
#[derive(Debug)]
pub struct Framed<T, U> {
#[pin]
inner: FramedRead2<FramedWrite2<Fuse<T, U>>>,
}
}
impl<T, U> Deref for Framed<T, U> {
type Target = T;
fn deref(&self) -> &T {
&self.inner
}
}
impl<T, U> DerefMut for Framed<T, U> {
fn deref_mut(&mut self) -> &mut T {
&mut self.inner
}
}
impl<T, U> Framed<T, U>
where
T: AsyncRead + AsyncWrite,
U: Decoder + Encoder,
{
/// Creates a new `Framed` transport with the given codec.
/// A codec is a type which implements `Decoder` and `Encoder`.
pub fn new(inner: T, codec: U) -> Self {
Self {
inner: framed_read_2(framed_write_2(Fuse::new(inner, codec), None), None),
}
}
/// Creates a new `Framed` from [`FramedParts`].
///
/// See also [`Framed::into_parts`].
pub fn from_parts(
FramedParts {
io,
codec,
write_buffer,
read_buffer,
..
}: FramedParts<T, U>,
) -> Self {
let framed_write = framed_write_2(Fuse::new(io, codec), Some(write_buffer));
let framed_read = framed_read_2(framed_write, Some(read_buffer));
Self { inner: framed_read }
}
/// Consumes the `Framed`, returning its parts, such that a new
/// `Framed` may be constructed, possibly with a different codec.
///
/// See also [`Framed::from_parts`].
pub fn into_parts(self) -> FramedParts<T, U> {
let (framed_write, read_buffer) = self.inner.into_parts();
let (fuse, write_buffer) = framed_write.into_parts();
FramedParts {
io: fuse.t,
codec: fuse.u,
read_buffer,
write_buffer,
_priv: (),
}
}
/// Consumes the `Framed`, returning its underlying I/O stream.
///
/// Note that data that has already been read or written but not yet
/// consumed by the decoder or flushed, respectively, is dropped.
/// To retain any such potentially buffered data, use [`Framed::into_parts()`].
pub fn into_inner(self) -> T {
self.into_parts().io
}
/// Returns a reference to the underlying codec wrapped by
/// `Framed`.
///
/// Note that care should be taken to not tamper with the underlying codec
/// as it may corrupt the stream of frames otherwise being worked with.
pub fn codec(&self) -> &U {
&self.inner.u
}
/// Returns a mutable reference to the underlying codec wrapped by
/// `Framed`.
///
/// Note that care should be taken to not tamper with the underlying codec
/// as it may corrupt the stream of frames otherwise being worked with.
pub fn codec_mut(&mut self) -> &mut U {
&mut self.inner.u
}
/// Returns a reference to the read buffer.
pub fn read_buffer(&self) -> &BytesMut {
self.inner.buffer()
}
/// High-water mark for writes, in bytes
///
/// See [`FramedWrite::send_high_water_mark`].
pub fn send_high_water_mark(&self) -> usize {
self.inner.high_water_mark
}
/// Sets high-water mark for writes, in bytes
///
/// See [`FramedWrite::set_send_high_water_mark`].
pub fn set_send_high_water_mark(&mut self, hwm: usize) {
self.inner.high_water_mark = hwm;
}
}
impl<T, U> Stream for Framed<T, U>
where
T: AsyncRead + Unpin,
U: Decoder,
{
type Item = Result<U::Item, U::Error>;
fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
self.inner.try_poll_next_unpin(cx)
}
}
impl<T, U> Sink<U::Item<'_>> for Framed<T, U>
where
T: AsyncWrite + Unpin,
U: Encoder,
{
type Error = U::Error;
fn poll_ready(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
self.project().inner.poll_ready(cx)
}
fn start_send(self: Pin<&mut Self>, item: U::Item<'_>) -> Result<(), Self::Error> {
self.project().inner.start_send(item)
}
fn poll_flush(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
self.project().inner.poll_flush(cx)
}
fn poll_close(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
self.project().inner.poll_close(cx)
}
}
/// The parts obtained from [`Framed::into_parts`].
pub struct FramedParts<T, U> {
/// The underlying I/O stream.
pub io: T,
/// The codec used for encoding and decoding frames.
pub codec: U,
/// The remaining read buffer, containing data that has been
/// read from `io` but not yet consumed by the codec's decoder.
pub read_buffer: BytesMut,
/// The remaining write buffer, containing framed data that has been
/// buffered but not yet flushed to `io`.
pub write_buffer: BytesMut,
/// Keep the constructor private.
_priv: (),
}
impl<T, U> FramedParts<T, U> {
/// Changes the codec used in this `FramedParts`.
pub fn map_codec<V, F>(self, f: F) -> FramedParts<T, V>
where
F: FnOnce(U) -> V,
{
FramedParts {
io: self.io,
codec: f(self.codec),
read_buffer: self.read_buffer,
write_buffer: self.write_buffer,
_priv: (),
}
}
}