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use crate::codec::encoder::Encoder;
use crate::codec::framed_impl::{FramedImpl, WriteFrame};
use futures_core::Stream;
use tokio::io::AsyncWrite;
use bytes::BytesMut;
use futures_sink::Sink;
use pin_project_lite::pin_project;
use std::fmt;
use std::io;
use std::pin::Pin;
use std::task::{Context, Poll};
pin_project! {
/// A [`Sink`] of frames encoded to an `AsyncWrite`.
///
/// For examples of how to use `FramedWrite` with a codec, see the
/// examples on the [`codec`] module.
///
/// # Cancellation safety
///
/// * [`futures_util::sink::SinkExt::send`]: if send is used as the event in a
/// `tokio::select!` statement and some other branch completes first, then it is
/// guaranteed that the message was not sent, but the message itself is lost.
///
/// [`Sink`]: futures_sink::Sink
/// [`codec`]: crate::codec
/// [`futures_util::sink::SinkExt::send`]: futures_util::sink::SinkExt::send
pub struct FramedWrite<T, E> {
#[pin]
inner: FramedImpl<T, E, WriteFrame>,
}
}
impl<T, E> FramedWrite<T, E>
where
T: AsyncWrite,
{
/// Creates a new `FramedWrite` with the given `encoder`.
pub fn new(inner: T, encoder: E) -> FramedWrite<T, E> {
FramedWrite {
inner: FramedImpl {
inner,
codec: encoder,
state: WriteFrame::default(),
},
}
}
}
impl<T, E> FramedWrite<T, E> {
/// Returns a reference to the underlying I/O stream wrapped by
/// `FramedWrite`.
///
/// Note that care should be taken to not tamper with the underlying stream
/// of data coming in as it may corrupt the stream of frames otherwise
/// being worked with.
pub fn get_ref(&self) -> &T {
&self.inner.inner
}
/// Returns a mutable reference to the underlying I/O stream wrapped by
/// `FramedWrite`.
///
/// Note that care should be taken to not tamper with the underlying stream
/// of data coming in as it may corrupt the stream of frames otherwise
/// being worked with.
pub fn get_mut(&mut self) -> &mut T {
&mut self.inner.inner
}
/// Returns a pinned mutable reference to the underlying I/O stream wrapped by
/// `FramedWrite`.
///
/// Note that care should be taken to not tamper with the underlying stream
/// of data coming in as it may corrupt the stream of frames otherwise
/// being worked with.
pub fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut T> {
self.project().inner.project().inner
}
/// Consumes the `FramedWrite`, returning its underlying I/O stream.
///
/// Note that care should be taken to not tamper with the underlying stream
/// of data coming in as it may corrupt the stream of frames otherwise
/// being worked with.
pub fn into_inner(self) -> T {
self.inner.inner
}
/// Returns a reference to the underlying encoder.
pub fn encoder(&self) -> &E {
&self.inner.codec
}
/// Returns a mutable reference to the underlying encoder.
pub fn encoder_mut(&mut self) -> &mut E {
&mut self.inner.codec
}
/// Maps the encoder `E` to `C`, preserving the write buffer
/// wrapped by `Framed`.
pub fn map_encoder<C, F>(self, map: F) -> FramedWrite<T, C>
where
F: FnOnce(E) -> C,
{
// This could be potentially simplified once rust-lang/rust#86555 hits stable
let FramedImpl {
inner,
state,
codec,
} = self.inner;
FramedWrite {
inner: FramedImpl {
inner,
state,
codec: map(codec),
},
}
}
/// Returns a mutable reference to the underlying encoder.
pub fn encoder_pin_mut(self: Pin<&mut Self>) -> &mut E {
self.project().inner.project().codec
}
/// Returns a reference to the write buffer.
pub fn write_buffer(&self) -> &BytesMut {
&self.inner.state.buffer
}
/// Returns a mutable reference to the write buffer.
pub fn write_buffer_mut(&mut self) -> &mut BytesMut {
&mut self.inner.state.buffer
}
/// Returns backpressure boundary
pub fn backpressure_boundary(&self) -> usize {
self.inner.state.backpressure_boundary
}
/// Updates backpressure boundary
pub fn set_backpressure_boundary(&mut self, boundary: usize) {
self.inner.state.backpressure_boundary = boundary;
}
}
// This impl just defers to the underlying FramedImpl
impl<T, I, E> Sink<I> for FramedWrite<T, E>
where
T: AsyncWrite,
E: Encoder<I>,
E::Error: From<io::Error>,
{
type Error = E::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: I) -> 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)
}
}
// This impl just defers to the underlying T: Stream
impl<T, D> Stream for FramedWrite<T, D>
where
T: Stream,
{
type Item = T::Item;
fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
self.project().inner.project().inner.poll_next(cx)
}
}
impl<T, U> fmt::Debug for FramedWrite<T, U>
where
T: fmt::Debug,
U: fmt::Debug,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("FramedWrite")
.field("inner", &self.get_ref())
.field("encoder", &self.encoder())
.field("buffer", &self.inner.state.buffer)
.finish()
}
}