| use std::pin::Pin; |
| use std::future::Future; |
| |
| use crate::io::{self, Write}; |
| use crate::task::{Context, Poll}; |
| |
| #[doc(hidden)] |
| #[allow(missing_debug_implementations)] |
| #[must_use] |
| pub struct WriteFmtFuture<'a, T: Unpin + ?Sized> { |
| pub(crate) writer: &'a mut T, |
| pub(crate) res: Option<io::Result<Vec<u8>>>, |
| pub(crate) buffer: Option<Vec<u8>>, |
| pub(crate) amt: u64, |
| } |
| |
| impl<T: Write + Unpin + ?Sized> Future for WriteFmtFuture<'_, T> { |
| type Output = io::Result<()>; |
| |
| fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { |
| // Process the interal Result the first time we run. |
| if self.buffer.is_none() { |
| match self.res.take().unwrap() { |
| Err(err) => return Poll::Ready(Err(err)), |
| Ok(buffer) => self.buffer = Some(buffer), |
| }; |
| } |
| |
| // Get the types from the future. |
| let Self { |
| writer, |
| amt, |
| buffer, |
| .. |
| } = &mut *self; |
| let buffer = buffer.as_mut().unwrap(); |
| |
| // Copy the data from the buffer into the writer until it's done. |
| loop { |
| if *amt == buffer.len() as u64 { |
| futures_core::ready!(Pin::new(&mut **writer).poll_flush(cx))?; |
| return Poll::Ready(Ok(())); |
| } |
| let i = futures_core::ready!(Pin::new(&mut **writer).poll_write(cx, buffer))?; |
| if i == 0 { |
| return Poll::Ready(Err(io::ErrorKind::WriteZero.into())); |
| } |
| *amt += i as u64; |
| } |
| } |
| } |