-
Notifications
You must be signed in to change notification settings - Fork 605
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Merge branch 'master' into pin-project-lite
- Loading branch information
Showing
6 changed files
with
188 additions
and
47 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,83 @@ | ||
use core::{future::Future, pin::Pin}; | ||
use futures_core::task::{Context, Poll}; | ||
use futures_sink::Sink; | ||
use pin_project::pin_project; | ||
|
||
/// Sink for the [`unfold`] function. | ||
#[pin_project] | ||
#[derive(Debug)] | ||
#[must_use = "sinks do nothing unless polled"] | ||
pub struct Unfold<T, F, R> { | ||
state: Option<T>, | ||
function: F, | ||
#[pin] | ||
future: Option<R>, | ||
} | ||
|
||
/// Create a sink from a function which processes one item at a time. | ||
/// | ||
/// # Examples | ||
/// | ||
/// ``` | ||
/// # futures::executor::block_on(async { | ||
/// use futures::sink::{self, SinkExt}; | ||
/// | ||
/// let unfold = sink::unfold(0, |mut sum, i: i32| { | ||
/// async move { | ||
/// sum += i; | ||
/// eprintln!("{}", i); | ||
/// Ok::<_, futures::never::Never>(sum) | ||
/// } | ||
/// }); | ||
/// futures::pin_mut!(unfold); | ||
/// unfold.send(5).await?; | ||
/// # Ok::<(), futures::never::Never>(()) }).unwrap(); | ||
/// ``` | ||
pub fn unfold<T, F, R>(init: T, function: F) -> Unfold<T, F, R> { | ||
Unfold { | ||
state: Some(init), | ||
function, | ||
future: None, | ||
} | ||
} | ||
|
||
impl<T, F, R, Item, E> Sink<Item> for Unfold<T, F, R> | ||
where | ||
F: FnMut(T, Item) -> R, | ||
R: Future<Output = Result<T, E>>, | ||
{ | ||
type Error = E; | ||
|
||
fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { | ||
self.poll_flush(cx) | ||
} | ||
|
||
fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error> { | ||
let mut this = self.project(); | ||
debug_assert!(this.future.is_none()); | ||
let future = (this.function)(this.state.take().unwrap(), item); | ||
this.future.set(Some(future)); | ||
Ok(()) | ||
} | ||
|
||
fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { | ||
let mut this = self.project(); | ||
Poll::Ready(if let Some(future) = this.future.as_mut().as_pin_mut() { | ||
let result = match ready!(future.poll(cx)) { | ||
Ok(state) => { | ||
*this.state = Some(state); | ||
Ok(()) | ||
} | ||
Err(err) => Err(err), | ||
}; | ||
this.future.set(None); | ||
result | ||
} else { | ||
Ok(()) | ||
}) | ||
} | ||
|
||
fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { | ||
self.poll_flush(cx) | ||
} | ||
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.