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feat: serio (#24)

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* feat: serio

* add IoStreamExt

* fix doc link

* add into_stream

* pin project IntoSink

* add flush method to SinkExt

* add duplex traits

* Apply suggestions from code review

Co-authored-by: dan <themighty1@users.noreply.github.com>

* add Framed test

---------

Co-authored-by: dan <themighty1@users.noreply.github.com>
This commit is contained in:
sinu.eth
2024-03-04 12:44:56 -08:00
committed by GitHub
parent 51f313d153
commit 8f2fc9e540
12 changed files with 1458 additions and 1 deletions
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10
Cargo.toml
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@@ -1,18 +1,23 @@
[workspace]
members = ["utils", "utils-aio", "spansy"]
members = ["utils", "utils-aio", "spansy", "serio"]
[workspace.dependencies]
tlsn-utils = { path = "utils" }
tlsn-utils-aio = { path = "utils-aio" }
spansy = { path = "spansy" }
serio = { path = "serio" }
rand = "0.8"
thiserror = "1"
async-trait = "0.1"
prost = "0.9"
futures = "0.3"
futures-sink = "0.3"
futures-core = "0.3"
futures-channel = "0.3"
futures-util = "0.3"
tokio-util = "0.7"
tokio-serde = "0.8"
tokio = "1.23"
async-tungstenite = "0.16"
prost-build = "0.9"
@@ -20,3 +25,6 @@ bytes = "1"
async-std = "1"
rayon = "1"
serde = "1"
cfg-if = "1"
bincode = "1.3"
pin-project-lite = "0.2"

33
serio/Cargo.toml Normal file
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[package]
name = "serio"
version = "0.1.0"
edition = "2021"
[features]
default = ["compat", "channel", "codec", "bincode"]
compat = ["dep:futures-sink"]
channel = ["dep:futures-channel"]
codec = ["dep:tokio-util"]
bincode = ["dep:bincode"]
[dependencies]
bytes.workspace = true
serde.workspace = true
pin-project-lite.workspace = true
futures-core.workspace = true
futures-channel = { workspace = true, optional = true }
futures-sink = { workspace = true, optional = true }
futures-util = { workspace = true, features = ["bilock", "unstable"] }
tokio-util = { workspace = true, features = ["codec"], optional = true }
bincode = { workspace = true, optional = true }
[dev-dependencies]
futures.workspace = true
serde = { workspace = true, features = ["derive"] }
tokio = { workspace = true, features = ["full"] }
tokio-util = { workspace = true, features = ["codec"] }
[[example]]
name = "tokio_codec"
path = "examples/tokio_codec.rs"
required-features = ["codec"]

203
serio/LICENSE-APACHE Normal file
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@@ -0,0 +1,203 @@
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Copyright (c) 2016 Alex Crichton
Copyright (c) 2017 The Tokio Authors
Copyright (c) 2024 The TLSNotary authors
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
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27
serio/LICENSE-MIT Normal file
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@@ -0,0 +1,27 @@
Copyright (c) 2016 Alex Crichton
Copyright (c) 2017 The Tokio Authors
Copyright (c) 2024 The TLSNotary authors
Permission is hereby granted, free of charge, to any
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
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CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.

11
serio/README.md Normal file
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# serio
This crate provides the `Sink` and `Stream` traits which are similar to `futures::Sink` and `futures::Stream` except they work with *any* serializable types.
Much of the functionality from this crate was either adapted or directly copied from the [`futures`](https://github.com/rust-lang/futures-rs/) project. Inspiration was also taken from the [`tokio-serde`](https://crates.io/crates/tokio-serde) crate.
# License
Licensed under either of Apache License, Version 2.0 or MIT license at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

47
serio/examples/tokio_codec.rs Normal file
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use serde::{Deserialize, Serialize};
use serio::{
codec::{Bincode, Framed},
IoSink, IoStream, SinkExt as _, StreamExt as _,
};
use std::io::Result;
use tokio::io::duplex;
use tokio_util::codec::LengthDelimitedCodec;
#[derive(Serialize, Deserialize)]
struct Ping(String);
#[derive(Serialize, Deserialize)]
struct Pong(u32);
#[tokio::main]
async fn main() {
let (a, b) = duplex(1024);
let a = LengthDelimitedCodec::builder().new_framed(a);
let b = LengthDelimitedCodec::builder().new_framed(b);
let a = Framed::new(a, Bincode::default());
let b = Framed::new(b, Bincode::default());
tokio::try_join!(alice(a), bob(b)).unwrap();
}
async fn alice<T: IoSink + IoStream + Unpin>(mut io: T) -> Result<()> {
io.send(Ping("hello bob!".to_string())).await?;
println!("alice: sent ping");
let Pong(num) = io.next().await.unwrap()?;
println!("alice: received pong {num}");
Ok(())
}
async fn bob<T: IoSink + IoStream + Unpin>(mut io: T) -> Result<()> {
let Ping(msg) = io.next().await.unwrap()?;
println!("bob: received ping \"{msg}\"");
io.send(Pong(42)).await?;
println!("bob: sent pong");
Ok(())
}

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serio/src/channel.rs Normal file
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//! Memory channels for sending and receiving serializable types. Useful for testing.
use std::{
any::Any,
io::{Error, ErrorKind},
pin::Pin,
task::{Context, Poll},
};
use futures_channel::mpsc;
use futures_core::Stream as _;
use futures_sink::Sink as _;
use crate::{Deserialize, Serialize, Sink, Stream};
type Item = Box<dyn Any + Send + Sync + 'static>;
/// A memory sink that can be used to send any serializable type to the receiver.
pub struct MemorySink(mpsc::Sender<Item>);
impl Sink for MemorySink {
type Error = Error;
fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Pin::new(&mut self.0)
.poll_ready(cx)
.map_err(|e| Error::new(ErrorKind::ConnectionAborted, e))
}
fn start_send<Item: Serialize>(
mut self: Pin<&mut Self>,
item: Item,
) -> Result<(), Self::Error> {
Pin::new(&mut self.0)
.start_send(Box::new(item))
.map_err(|e| Error::new(ErrorKind::ConnectionAborted, e))
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Pin::new(&mut self.0)
.poll_flush(cx)
.map_err(|e| Error::new(ErrorKind::ConnectionAborted, e))
}
fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Pin::new(&mut self.0)
.poll_close(cx)
.map_err(|e| Error::new(ErrorKind::ConnectionAborted, e))
}
}
/// A memory stream that can be used to receive any deserializable type from the sender.
pub struct MemoryStream(mpsc::Receiver<Item>);
impl Stream for MemoryStream {
type Error = Error;
fn poll_next<Item: Deserialize>(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Item, Self::Error>>> {
Pin::new(&mut self.0).poll_next(cx).map(|item| {
item.map(|item| {
item.downcast().map(|item| *item).map_err(|_| {
Error::new(ErrorKind::InvalidData, "sender sent an unexpected type")
})
})
})
}
}
/// Creates a new memory channel with the specified buffer size.
pub fn channel(buffer: usize) -> (MemorySink, MemoryStream) {
let (sender, receiver) = mpsc::channel(buffer);
(MemorySink(sender), MemoryStream(receiver))
}
/// A memory duplex that can be used to send and receive any serializable types.
pub struct MemoryDuplex {
sink: MemorySink,
stream: MemoryStream,
}
impl MemoryDuplex {
/// Returns the inner sink and stream.
pub fn into_inner(self) -> (MemorySink, MemoryStream) {
(self.sink, self.stream)
}
/// Returns a reference to the inner sink.
pub fn sink_mut(&mut self) -> &mut MemorySink {
&mut self.sink
}
/// Returns a reference to the inner stream.
pub fn stream_mut(&mut self) -> &mut MemoryStream {
&mut self.stream
}
}
impl Sink for MemoryDuplex {
type Error = Error;
fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Pin::new(&mut self.sink).poll_ready(cx)
}
fn start_send<Item: Serialize>(
mut self: Pin<&mut Self>,
item: Item,
) -> Result<(), Self::Error> {
Pin::new(&mut self.sink).start_send(item)
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Pin::new(&mut self.sink).poll_flush(cx)
}
fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Pin::new(&mut self.sink).poll_close(cx)
}
}
impl Stream for MemoryDuplex {
type Error = Error;
fn poll_next<Item: Deserialize>(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Item, Self::Error>>> {
Pin::new(&mut self.stream).poll_next(cx)
}
}
/// Creates a new memory duplex with the specified buffer size.
pub fn duplex(buffer: usize) -> (MemoryDuplex, MemoryDuplex) {
let (a, b) = channel(buffer);
let (c, d) = channel(buffer);
(
MemoryDuplex { sink: a, stream: d },
MemoryDuplex { sink: c, stream: b },
)
}
#[cfg(test)]
mod tests {
use super::*;
use crate::{SinkExt, StreamExt};
#[test]
fn test_channel() {
let (mut sink, mut stream) = channel(1);
futures::executor::block_on(async {
sink.send(42u8).await.unwrap();
assert_eq!(stream.next::<u8>().await.unwrap().unwrap(), 42);
})
}
#[test]
#[should_panic]
fn test_channel_type_mismatch() {
let (mut sink, mut stream) = channel(1);
futures::executor::block_on(async {
sink.send(42u16).await.unwrap();
stream.next::<u8>().await.unwrap().unwrap();
})
}
#[test]
fn test_duplex() {
let (mut a, mut b) = duplex(1);
futures::executor::block_on(async {
a.send(42u8).await.unwrap();
assert_eq!(b.next::<u8>().await.unwrap().unwrap(), 42);
})
}
#[test]
#[should_panic]
fn test_duplex_type_mismatch() {
let (mut a, mut b) = duplex(1);
futures::executor::block_on(async {
a.send(42u16).await.unwrap();
b.next::<u8>().await.unwrap().unwrap();
})
}
}

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//! Utilities for converting framed transports to streams and sinks using a codec.
use std::{
io::{Error, ErrorKind},
pin::Pin,
task::{ready, Context, Poll},
};
use bytes::{Bytes, BytesMut};
use futures_core::stream::TryStream;
use crate::{Deserialize, Serialize, Sink, Stream};
/// A serializer.
pub trait Serializer {
/// The error type.
type Error;
/// Serializes `item` into a buffer.
fn serialize<T: Serialize>(&mut self, item: &T) -> Result<Bytes, Self::Error>;
}
/// A deserializer.
pub trait Deserializer {
/// The error type.
type Error;
/// Deserializes a buffer into a value.
fn deserialize<T: Deserialize>(&mut self, buf: &BytesMut) -> Result<T, Self::Error>;
}
#[cfg(feature = "bincode")]
mod bincode_impl {
use super::*;
use bincode::{deserialize, serialize};
/// A bincode codec.
#[derive(Default, Clone)]
pub struct Bincode;
impl Serializer for Bincode {
type Error = bincode::Error;
fn serialize<T: Serialize>(&mut self, item: &T) -> Result<Bytes, Self::Error> {
Ok(Bytes::from(serialize(item)?))
}
}
impl Deserializer for Bincode {
type Error = bincode::Error;
fn deserialize<T: Deserialize>(&mut self, buf: &BytesMut) -> Result<T, Self::Error> {
Ok(deserialize(buf)?)
}
}
}
#[cfg(feature = "bincode")]
pub use bincode_impl::Bincode;
/// A framed transport.
pub struct Framed<T, C> {
inner: T,
codec: C,
}
impl<T, C> Framed<T, C> {
/// Creates a new `Framed` with the given transport and codec.
pub fn new(inner: T, codec: C) -> Self {
Self { inner, codec }
}
}
impl<T, C> Sink for Framed<T, C>
where
T: futures_sink::Sink<Bytes, Error = Error> + Unpin,
C: Serializer + Unpin,
<C as Serializer>::Error: Into<Box<dyn std::error::Error + Send + Sync>>,
{
type Error = Error;
fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Pin::new(&mut self.inner).poll_ready(cx)
}
fn start_send<I: Serialize>(
mut self: std::pin::Pin<&mut Self>,
item: I,
) -> Result<(), Self::Error> {
let buf = self
.codec
.serialize(&item)
.map_err(|e| Error::new(ErrorKind::InvalidData, e))?;
Pin::new(&mut self.inner).start_send(buf)
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Pin::new(&mut self.inner).poll_flush(cx)
}
fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Pin::new(&mut self.inner).poll_close(cx)
}
}
impl<T, C> Stream for Framed<T, C>
where
T: TryStream<Ok = BytesMut, Error = Error> + Unpin,
C: Deserializer + Unpin,
<C as Deserializer>::Error: Into<Box<dyn std::error::Error + Send + Sync>>,
{
type Error = Error;
fn poll_next<Item: Deserialize>(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Item, Error>>> {
let Some(buf) = ready!(Pin::new(&mut self.inner).try_poll_next(cx)) else {
return Poll::Ready(None);
};
let item = self
.codec
.deserialize(&buf?)
.map_err(|e| Error::new(ErrorKind::InvalidData, e));
Poll::Ready(Some(item))
}
}
#[cfg(test)]
mod tests {
use serde::{Deserialize, Serialize};
use tokio::io::duplex;
use tokio_util::codec::LengthDelimitedCodec;
use crate::{SinkExt, StreamExt};
use super::*;
#[derive(Serialize, Deserialize)]
struct Ping;
#[derive(Serialize, Deserialize)]
struct Pong;
#[test]
fn test_framed() {
let (a, b) = duplex(1024);
let a = LengthDelimitedCodec::builder().new_framed(a);
let b = LengthDelimitedCodec::builder().new_framed(b);
let mut a = Framed::new(a, Bincode::default());
let mut b = Framed::new(b, Bincode::default());
let a = async {
a.send(Ping).await.unwrap();
a.next::<Pong>().await.unwrap().unwrap();
};
let b = async {
b.next::<Ping>().await.unwrap().unwrap();
b.send(Pong).await.unwrap();
};
futures::executor::block_on(async {
futures::join!(a, b);
});
}
}

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use std::future::Future;
// Just a helper function to ensure the futures we're returning all have the
// right implementations.
pub(crate) fn assert_future<T, F>(future: F) -> F
where
F: Future<Output = T>,
{
future
}

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serio/src/lib.rs Normal file
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#![doc = include_str!("../README.md")]
#![deny(missing_docs, unreachable_pub, unused_must_use)]
#![deny(clippy::all)]
#[cfg(feature = "channel")]
pub mod channel;
#[cfg(feature = "codec")]
pub mod codec;
pub(crate) mod future;
pub mod sink;
pub mod stream;
#[cfg(feature = "codec")]
pub use codec::{Deserializer, Framed, Serializer};
pub use sink::{IoSink, Sink, SinkExt};
pub use stream::{IoStream, Stream, StreamExt};
/// A serializable type.
pub trait Serialize: serde::Serialize + Send + Sync + Unpin + 'static {}
impl<T> Serialize for T where T: serde::Serialize + Send + Sync + Unpin + 'static {}
/// A deserializable type.
pub trait Deserialize: serde::de::DeserializeOwned + Send + Sync + Unpin + 'static {}
impl<T> Deserialize for T where T: serde::de::DeserializeOwned + Send + Sync + Unpin + 'static {}
/// A duplex.
pub trait Duplex<T, E>: Sink<Error = E> + Stream<Error = E> {}
impl<T, U, E> Duplex<U, E> for T where T: Sink<Error = E> + Stream<Error = E> {}
/// A duplex with a `std::io::Error` error type.
pub trait IoDuplex<T>: Duplex<T, std::io::Error> {}
impl<T, U> IoDuplex<U> for T where T: Duplex<U, std::io::Error> {}

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//! Sink types and traits.
use std::{
future::Future,
marker::PhantomData,
ops::DerefMut,
pin::Pin,
task::{ready, Context, Poll},
};
use crate::{future::assert_future, Serialize};
/// A sink with an error type of `std::io::Error`.
pub trait IoSink: Sink<Error = std::io::Error> {}
impl<T: ?Sized> IoSink for T where T: Sink<Error = std::io::Error> {}
/// A sink which accepts any item which implements `Serialize`.
///
/// This trait is similar to [`futures::Sink`](https://docs.rs/futures/latest/futures/sink/trait.Sink.html),
/// but facilitates sending of any serializable type instead of a single type.
#[must_use = "sinks do nothing unless polled"]
pub trait Sink {
/// The type of value produced by the sink when an error occurs.
type Error;
/// Attempts to prepare the `Sink` to receive a value.
///
/// This method must be called and return `Poll::Ready(Ok(()))` prior to
/// each call to `start_send`.
///
/// This method returns `Poll::Ready` once the underlying sink is ready to
/// receive data. If this method returns `Poll::Pending`, the current task
/// is registered to be notified (via `cx.waker().wake_by_ref()`) when `poll_ready`
/// should be called again.
///
/// In most cases, if the sink encounters an error, the sink will
/// permanently be unable to receive items.
fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>;
/// Begin the process of sending a value to the sink.
/// Each call to this function must be preceded by a successful call to
/// `poll_ready` which returned `Poll::Ready(Ok(()))`.
///
/// As the name suggests, this method only *begins* the process of sending
/// the item. If the sink employs buffering, the item isn't fully processed
/// until the buffer is fully flushed. Since sinks are designed to work with
/// asynchronous I/O, the process of actually writing out the data to an
/// underlying object takes place asynchronously. **You *must* use
/// `poll_flush` or `poll_close` in order to guarantee completion of a
/// send**.
///
/// Implementations of `poll_ready` and `start_send` will usually involve
/// flushing behind the scenes in order to make room for new messages.
/// It is only necessary to call `poll_flush` if you need to guarantee that
/// *all* of the items placed into the `Sink` have been sent.
///
/// In most cases, if the sink encounters an error, the sink will
/// permanently be unable to receive items.
fn start_send<Item: Serialize>(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error>;
/// Flush any remaining output from this sink.
///
/// Returns `Poll::Ready(Ok(()))` when no buffered items remain. If this
/// value is returned then it is guaranteed that all previous values sent
/// via `start_send` have been flushed.
///
/// Returns `Poll::Pending` if there is more work left to do, in which
/// case the current task is scheduled (via `cx.waker().wake_by_ref()`) to wake up when
/// `poll_flush` should be called again.
///
/// In most cases, if the sink encounters an error, the sink will
/// permanently be unable to receive items.
fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>;
/// Flush any remaining output and close this sink, if necessary.
///
/// Returns `Poll::Ready(Ok(()))` when no buffered items remain and the sink
/// has been successfully closed.
///
/// Returns `Poll::Pending` if there is more work left to do, in which
/// case the current task is scheduled (via `cx.waker().wake_by_ref()`) to wake up when
/// `poll_close` should be called again.
///
/// If this function encounters an error, the sink should be considered to
/// have failed permanently, and no more `Sink` methods should be called.
fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>;
}
impl<S: ?Sized + Sink + Unpin> Sink for &mut S {
type Error = S::Error;
fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Pin::new(&mut **self).poll_ready(cx)
}
fn start_send<Item: Serialize>(
mut self: Pin<&mut Self>,
item: Item,
) -> Result<(), Self::Error> {
Pin::new(&mut **self).start_send(item)
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Pin::new(&mut **self).poll_flush(cx)
}
fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
Pin::new(&mut **self).poll_close(cx)
}
}
impl<P> Sink for Pin<P>
where
P: DerefMut + Unpin,
P::Target: Sink,
{
type Error = <P::Target as Sink>::Error;
fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.get_mut().as_mut().poll_ready(cx)
}
fn start_send<Item: Serialize>(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error> {
self.get_mut().as_mut().start_send(item)
}
fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.get_mut().as_mut().poll_flush(cx)
}
fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.get_mut().as_mut().poll_close(cx)
}
}
/// An extension trait for Sinks that provides a variety of convenient functions.
pub trait SinkExt: Sink {
/// Close the sink.
fn close(&mut self) -> Close<'_, Self>
where
Self: Unpin,
{
assert_future::<Result<(), Self::Error>, _>(Close::new(self))
}
/// A future that completes after the given item has been fully processed
/// into the sink, including flushing.
///
/// Note that, **because of the flushing requirement, it is usually better
/// to batch together items to send via `feed` or `send_all`,
/// rather than flushing between each item.**
fn send<Item: Serialize>(&mut self, item: Item) -> Send<'_, Self, Item>
where
Self: Unpin,
{
assert_future::<Result<(), Self::Error>, _>(Send::new(self, item))
}
/// A future that completes after the given item has been received
/// by the sink.
///
/// Unlike `send`, the returned future does not flush the sink.
/// It is the caller's responsibility to ensure all pending items
/// are processed, which can be done via `flush` or `close`.
fn feed<Item: Serialize>(&mut self, item: Item) -> Feed<'_, Self, Item>
where
Self: Unpin,
{
assert_future::<Result<(), Self::Error>, _>(Feed::new(self, item))
}
/// A future that completes after the sink has been flushed.
fn flush(&mut self) -> Flush<'_, Self>
where
Self: Unpin,
{
assert_future::<Result<(), Self::Error>, _>(Flush::new(self))
}
/// Convert this sink into a `futures::Sink`.
#[cfg(feature = "compat")]
fn into_sink<Item: Serialize>(self) -> IntoSink<Self, Item>
where
Self: Sized,
{
assert_futures_sink(IntoSink::new(self))
}
}
impl<S: Sink + ?Sized> SinkExt for S {}
/// Future for the [`close`](SinkExt::close) method.
#[derive(Debug)]
#[must_use = "futures do nothing unless you `.await` or poll them"]
pub struct Close<'a, Si: ?Sized> {
sink: &'a mut Si,
}
impl<Si: Unpin + ?Sized> Unpin for Close<'_, Si> {}
/// A future that completes when the sink has finished closing.
///
/// The sink itself is returned after closing is complete.
impl<'a, Si: Sink + Unpin + ?Sized> Close<'a, Si> {
fn new(sink: &'a mut Si) -> Self {
Self { sink }
}
}
impl<Si: Sink + Unpin + ?Sized> Future for Close<'_, Si> {
type Output = Result<(), Si::Error>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
Pin::new(&mut self.sink).poll_close(cx)
}
}
/// Future for the [`send`](SinkExt::send) method.
#[derive(Debug)]
#[must_use = "futures do nothing unless you `.await` or poll them"]
pub struct Send<'a, Si: ?Sized, Item> {
feed: Feed<'a, Si, Item>,
}
// Pinning is never projected to children.
impl<Si: Unpin + ?Sized, Item> Unpin for Send<'_, Si, Item> {}
impl<'a, Si: Sink + Unpin + ?Sized, Item> Send<'a, Si, Item> {
fn new(sink: &'a mut Si, item: Item) -> Self {
Self {
feed: Feed::new(sink, item),
}
}
}
impl<Si: Sink + Unpin + ?Sized, Item: Serialize> Future for Send<'_, Si, Item> {
type Output = Result<(), Si::Error>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let this = &mut *self;
if this.feed.is_item_pending() {
ready!(Pin::new(&mut this.feed).poll(cx))?;
debug_assert!(!this.feed.is_item_pending());
}
// We're done sending the item, but want to block on flushing the
// sink.
ready!(this.feed.sink_pin_mut().poll_flush(cx))?;
Poll::Ready(Ok(()))
}
}
/// Future for the [`feed`](SinkExt::feed) method.
#[derive(Debug)]
#[must_use = "futures do nothing unless you `.await` or poll them"]
pub struct Feed<'a, Si: ?Sized, Item> {
sink: &'a mut Si,
item: Option<Item>,
}
// Pinning is never projected to children.
impl<Si: Unpin + ?Sized, Item> Unpin for Feed<'_, Si, Item> {}
impl<'a, Si: Sink + Unpin + ?Sized, Item> Feed<'a, Si, Item> {
fn new(sink: &'a mut Si, item: Item) -> Self {
Feed {
sink,
item: Some(item),
}
}
fn sink_pin_mut(&mut self) -> Pin<&mut Si> {
Pin::new(self.sink)
}
fn is_item_pending(&self) -> bool {
self.item.is_some()
}
}
impl<Si: Sink + Unpin + ?Sized, Item: Serialize> Future for Feed<'_, Si, Item> {
type Output = Result<(), Si::Error>;
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let this = self.get_mut();
let mut sink = Pin::new(&mut this.sink);
ready!(sink.as_mut().poll_ready(cx))?;
let item = this.item.take().expect("polled Feed after completion");
sink.as_mut().start_send(item)?;
Poll::Ready(Ok(()))
}
}
/// Future for the [`flush`](SinkExt::flush) method.
#[derive(Debug)]
#[must_use = "futures do nothing unless you `.await` or poll them"]
pub struct Flush<'a, Si: ?Sized> {
sink: &'a mut Si,
}
impl<Si: Unpin + ?Sized> Unpin for Flush<'_, Si> {}
impl<'a, Si: Sink + Unpin + ?Sized> Flush<'a, Si> {
fn new(sink: &'a mut Si) -> Self {
Self { sink }
}
}
impl<Si: Sink + Unpin + ?Sized> Future for Flush<'_, Si> {
type Output = Result<(), Si::Error>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
Pin::new(&mut self.sink).poll_flush(cx)
}
}
#[cfg(feature = "compat")]
mod compat {
use super::*;
pin_project_lite::pin_project! {
/// Wraps a sink and provides a `futures::Sink` implementation.
pub struct IntoSink<Si, Item> {
#[pin]
sink: Si,
_pd: PhantomData<Item>,
}
}
impl<Si, Item> IntoSink<Si, Item> {
pub(super) fn new(sink: Si) -> Self {
Self {
sink,
_pd: PhantomData,
}
}
/// Returns a reference to the inner sink.
pub fn sink(&self) -> &Si {
&self.sink
}
/// Returns a mutable reference to the inner sink.
pub fn sink_mut(&mut self) -> &mut Si {
&mut self.sink
}
/// Returns the inner sink.
pub fn into_inner(self) -> Si {
self.sink
}
}
impl<Si, Item> futures_sink::Sink<Item> for IntoSink<Si, Item>
where
Si: Sink,
Item: Serialize,
{
type Error = Si::Error;
fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.project().sink.poll_ready(cx)
}
fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error> {
self.project().sink.start_send(item)
}
fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.project().sink.poll_flush(cx)
}
fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.project().sink.poll_close(cx)
}
}
}
#[cfg(feature = "compat")]
pub use compat::IntoSink;
pub(crate) fn assert_futures_sink<S: futures_sink::Sink<Item>, Item>(sink: S) -> S {
sink
}

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//! Stream types and traits.
use std::{
future::Future,
marker::PhantomData,
ops::DerefMut,
pin::Pin,
task::{ready, Context, Poll},
};
use futures_core::FusedFuture;
use crate::{future::assert_future, Deserialize};
/// A stream with an error type of `std::io::Error`.
pub trait IoStream: Stream<Error = std::io::Error> {}
impl<T: ?Sized> IoStream for T where T: Stream<Error = std::io::Error> {}
/// A stream producing any kind of value which implements `Deserialize`.
///
/// This trait is similar to [`futures::Stream`](https://docs.rs/futures/latest/futures/stream/trait.Stream.html),
/// but facilitates receiving of any deserializable type instead of a single type.
#[must_use = "streams do nothing unless polled"]
pub trait Stream {
/// The type of value produced by the stream when an error occurs.
type Error;
/// Attempt to pull out the next value of this stream, registering the
/// current task for wakeup if the value is not yet available, and returning
/// `None` if the stream is exhausted.
///
/// # Return value
///
/// There are several possible return values, each indicating a distinct
/// stream state:
///
/// - `Poll::Pending` means that this stream's next value is not ready
/// yet. Implementations will ensure that the current task will be notified
/// when the next value may be ready.
///
/// - `Poll::Ready(Some(val))` means that the stream has successfully
/// produced a value, `val`, and may produce further values on subsequent
/// `poll_next` calls.
///
/// - `Poll::Ready(None)` means that the stream has terminated, and
/// `poll_next` should not be invoked again.
fn poll_next<Item: Deserialize>(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Item, Self::Error>>>;
/// Returns the bounds on the remaining length of the stream.
///
/// Specifically, `size_hint()` returns a tuple where the first element
/// is the lower bound, and the second element is the upper bound.
///
/// The second half of the tuple that is returned is an [`Option`]`<`[`usize`]`>`.
/// A [`None`] here means that either there is no known upper bound, or the
/// upper bound is larger than [`usize`].
///
/// # Implementation notes
///
/// It is not enforced that a stream implementation yields the declared
/// number of elements. A buggy stream may yield less than the lower bound
/// or more than the upper bound of elements.
///
/// `size_hint()` is primarily intended to be used for optimizations such as
/// reserving space for the elements of the stream, but must not be
/// trusted to e.g., omit bounds checks in unsafe code. An incorrect
/// implementation of `size_hint()` should not lead to memory safety
/// violations.
///
/// That said, the implementation should provide a correct estimation,
/// because otherwise it would be a violation of the trait's protocol.
///
/// The default implementation returns `(0, `[`None`]`)` which is correct for any
/// stream.
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
(0, None)
}
}
impl<S: ?Sized + Stream + Unpin> Stream for &mut S {
type Error = S::Error;
fn poll_next<Item: Deserialize>(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Item, Self::Error>>> {
S::poll_next(Pin::new(&mut **self), cx)
}
fn size_hint(&self) -> (usize, Option<usize>) {
(**self).size_hint()
}
}
impl<P> Stream for Pin<P>
where
P: DerefMut + Unpin,
P::Target: Stream,
{
type Error = <P::Target as Stream>::Error;
fn poll_next<Item: Deserialize>(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Item, Self::Error>>> {
self.get_mut().as_mut().poll_next(cx)
}
fn size_hint(&self) -> (usize, Option<usize>) {
(**self).size_hint()
}
}
/// A stream which tracks whether or not the underlying stream
/// should no longer be polled.
///
/// `is_terminated` will return `true` if a future should no longer be polled.
/// Usually, this state occurs after `poll_next` (or `try_poll_next`) returned
/// `Poll::Ready(None)`. However, `is_terminated` may also return `true` if a
/// stream has become inactive and can no longer make progress and should be
/// ignored or dropped rather than being polled again.
pub trait FusedStream: Stream {
/// Returns `true` if the stream should no longer be polled.
fn is_terminated(&self) -> bool;
}
impl<F: ?Sized + FusedStream + Unpin> FusedStream for &mut F {
fn is_terminated(&self) -> bool {
<F as FusedStream>::is_terminated(&**self)
}
}
impl<P> FusedStream for Pin<P>
where
P: DerefMut + Unpin,
P::Target: FusedStream,
{
fn is_terminated(&self) -> bool {
<P::Target as FusedStream>::is_terminated(&**self)
}
}
/// An extension trait for Streams that provides a variety of convenient functions.
pub trait StreamExt: Stream {
/// Creates a future that resolves to the next item in the stream.
///
/// Note that because `next` doesn't take ownership over the stream,
/// the [`Stream`] type must be [`Unpin`]. If you want to use `next` with a
/// [`!Unpin`](Unpin) stream, you'll first have to pin the stream. This can
/// be done by boxing the stream using [`Box::pin`] or
/// pinning it to the stack using the `pin_mut!` macro from the `pin_utils`
/// crate.
///
/// # Examples
///
/// ```
/// # futures::executor::block_on(async {
/// use futures::stream::{self, StreamExt};
///
/// let mut stream = stream::iter(1..=3);
///
/// assert_eq!(stream.next().await, Some(1));
/// assert_eq!(stream.next().await, Some(2));
/// assert_eq!(stream.next().await, Some(3));
/// assert_eq!(stream.next().await, None);
/// # });
/// ```
fn next<Item: Deserialize>(&mut self) -> Next<'_, Self, Item>
where
Self: Unpin,
{
assert_future::<Option<Result<Item, Self::Error>>, _>(Next::new(self))
}
/// Converts this stream into a `futures::Stream`.
#[cfg(feature = "compat")]
fn into_stream<Item: Deserialize>(self) -> IntoStream<Self, Item>
where
Self: Sized,
{
assert_futures_stream(IntoStream::new(self))
}
/// A convenience method for calling [`Stream::poll_next`] on [`Unpin`]
/// stream types.
fn poll_next_unpin<Item: Deserialize>(
&mut self,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Item, Self::Error>>>
where
Self: Unpin,
{
Pin::new(self).poll_next(cx)
}
}
impl<S: Stream + ?Sized> StreamExt for S {}
/// Future for the [`next`](StreamExt::next) method.
#[derive(Debug)]
#[must_use = "futures do nothing unless you `.await` or poll them"]
pub struct Next<'a, St: ?Sized, Item> {
stream: &'a mut St,
_pd: PhantomData<Item>,
}
impl<St: ?Sized + Unpin, Item> Unpin for Next<'_, St, Item> {}
impl<'a, St: ?Sized + Stream + Unpin, Item> Next<'a, St, Item> {
pub(super) fn new(stream: &'a mut St) -> Self {
Self {
stream,
_pd: PhantomData,
}
}
}
impl<St: ?Sized + FusedStream + Unpin, Item: Deserialize> FusedFuture for Next<'_, St, Item> {
fn is_terminated(&self) -> bool {
self.stream.is_terminated()
}
}
impl<St: ?Sized + Stream + Unpin, Item: Deserialize> Future for Next<'_, St, Item> {
type Output = Option<Result<Item, St::Error>>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
self.stream.poll_next_unpin(cx)
}
}
#[cfg(feature = "compat")]
mod compat {
use super::*;
pin_project_lite::pin_project! {
/// Wraps a stream and provides a `futures::Stream` implementation.
pub struct IntoStream<St, Item> {
#[pin]
stream: St,
_pd: PhantomData<Item>,
}
}
impl<St, Item> IntoStream<St, Item> {
pub(super) fn new(stream: St) -> Self {
Self {
stream,
_pd: PhantomData,
}
}
/// Returns a reference to the inner stream.
pub fn stream(&self) -> &St {
&self.stream
}
/// Returns a mutable reference to the inner stream.
pub fn stream_mut(&mut self) -> &mut St {
&mut self.stream
}
/// Returns the inner stream.
pub fn into_inner(self) -> St {
self.stream
}
}
impl<St, Item> futures_core::Stream for IntoStream<St, Item>
where
St: Stream,
Item: Deserialize,
{
type Item = Result<Item, St::Error>;
fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
self.project().stream.poll_next(cx)
}
}
}
#[cfg(feature = "compat")]
pub use compat::IntoStream;
/// An extension trait for [`IoStream`] which provides a variety of convenient functions.
pub trait IoStreamExt: IoStream {
/// Creates a future that resolves to the next item in the stream, returning
/// an error if the stream is exhausted.
fn expect_next<Item: Deserialize>(&mut self) -> ExpectNext<'_, Self, Item>
where
Self: Unpin,
{
ExpectNext {
next: self.next(),
_pd: PhantomData,
}
}
}
impl<S: ?Sized> IoStreamExt for S where S: IoStream {}
/// Future for the [`expect_next`](IoStreamExt::expect_next) method.
#[derive(Debug)]
#[must_use = "futures do nothing unless you `.await` or poll them"]
pub struct ExpectNext<'a, St: ?Sized, Item> {
next: Next<'a, St, Item>,
_pd: PhantomData<Item>,
}
impl<St: ?Sized + Unpin, Item> Unpin for ExpectNext<'_, St, Item> {}
impl<'a, St: ?Sized + IoStream + Unpin, Item: Deserialize> Future for ExpectNext<'a, St, Item> {
type Output = Result<Item, St::Error>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
match ready!(Pin::new(&mut self.next).poll(cx)) {
Some(Ok(item)) => Poll::Ready(Ok(item)),
Some(Err(err)) => Poll::Ready(Err(err)),
None => Poll::Ready(Err(std::io::ErrorKind::UnexpectedEof.into())),
}
}
}
pub(crate) fn assert_futures_stream<S: futures_core::Stream>(stream: S) -> S {
stream
}