| use crate::stream::{Fuse, StreamExt, TryStreamExt}; |
| use core::fmt; |
| use core::pin::Pin; |
| use futures_core::future::Future; |
| use futures_core::ready; |
| use futures_core::stream::{Stream, TryStream}; |
| use futures_core::task::{Context, Poll}; |
| use futures_sink::Sink; |
| |
| /// Future for the [`send_all`](super::SinkExt::send_all) method. |
| #[allow(explicit_outlives_requirements)] // https://github.com/rust-lang/rust/issues/60993 |
| #[must_use = "futures do nothing unless you `.await` or poll them"] |
| pub struct SendAll<'a, Si, St> |
| where |
| Si: ?Sized, |
| St: ?Sized + TryStream, |
| { |
| sink: &'a mut Si, |
| stream: Fuse<&'a mut St>, |
| buffered: Option<St::Ok>, |
| } |
| |
| impl<Si, St> fmt::Debug for SendAll<'_, Si, St> |
| where |
| Si: fmt::Debug + ?Sized, |
| St: fmt::Debug + ?Sized + TryStream, |
| St::Ok: fmt::Debug, |
| { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| f.debug_struct("SendAll") |
| .field("sink", &self.sink) |
| .field("stream", &self.stream) |
| .field("buffered", &self.buffered) |
| .finish() |
| } |
| } |
| |
| // Pinning is never projected to any fields |
| impl<Si, St> Unpin for SendAll<'_, Si, St> |
| where |
| Si: Unpin + ?Sized, |
| St: TryStream + Unpin + ?Sized, |
| { |
| } |
| |
| impl<'a, Si, St, Ok, Error> SendAll<'a, Si, St> |
| where |
| Si: Sink<Ok, Error = Error> + Unpin + ?Sized, |
| St: TryStream<Ok = Ok, Error = Error> + Stream + Unpin + ?Sized, |
| { |
| pub(super) fn new(sink: &'a mut Si, stream: &'a mut St) -> Self { |
| Self { sink, stream: stream.fuse(), buffered: None } |
| } |
| |
| fn try_start_send( |
| &mut self, |
| cx: &mut Context<'_>, |
| item: St::Ok, |
| ) -> Poll<Result<(), Si::Error>> { |
| debug_assert!(self.buffered.is_none()); |
| match Pin::new(&mut self.sink).poll_ready(cx)? { |
| Poll::Ready(()) => Poll::Ready(Pin::new(&mut self.sink).start_send(item)), |
| Poll::Pending => { |
| self.buffered = Some(item); |
| Poll::Pending |
| } |
| } |
| } |
| } |
| |
| impl<Si, St, Ok, Error> Future for SendAll<'_, Si, St> |
| where |
| Si: Sink<Ok, Error = Error> + Unpin + ?Sized, |
| St: Stream<Item = Result<Ok, Error>> + Unpin + ?Sized, |
| { |
| type Output = Result<(), Error>; |
| |
| fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { |
| let this = &mut *self; |
| // If we've got an item buffered already, we need to write it to the |
| // sink before we can do anything else |
| if let Some(item) = this.buffered.take() { |
| ready!(this.try_start_send(cx, item))? |
| } |
| |
| loop { |
| match this.stream.try_poll_next_unpin(cx)? { |
| Poll::Ready(Some(item)) => ready!(this.try_start_send(cx, item))?, |
| Poll::Ready(None) => { |
| ready!(Pin::new(&mut this.sink).poll_flush(cx))?; |
| return Poll::Ready(Ok(())); |
| } |
| Poll::Pending => { |
| ready!(Pin::new(&mut this.sink).poll_flush(cx))?; |
| return Poll::Pending; |
| } |
| } |
| } |
| } |
| } |