blob: f8147ade30324aad2b7adf53965703b285aa01d7 [file] [log] [blame]
use futures_core::future::Future;
use futures_core::task::{self, Poll};
use futures_io::AsyncWrite;
use std::io;
use std::marker::Unpin;
use std::mem;
use std::pin::PinMut;
/// A future used to write the entire contents of some data to a stream.
///
/// This is created by the [`write_all`] top-level method.
///
/// [`write_all`]: fn.write_all.html
#[derive(Debug)]
pub struct WriteAll<'a, W: ?Sized + 'a> {
writer: &'a mut W,
buf: &'a [u8],
}
// Pinning is never projected to fields
impl<W: ?Sized> Unpin for WriteAll<'_, W> {}
impl<'a, W: AsyncWrite + ?Sized> WriteAll<'a, W> {
pub(super) fn new(writer: &'a mut W, buf: &'a [u8]) -> Self {
WriteAll { writer, buf }
}
}
fn zero_write() -> io::Error {
io::Error::new(io::ErrorKind::WriteZero, "zero-length write")
}
impl<W: AsyncWrite + ?Sized> Future for WriteAll<'_, W> {
type Output = io::Result<()>;
fn poll(mut self: PinMut<Self>, cx: &mut task::Context) -> Poll<io::Result<()>> {
let this = &mut *self;
while !this.buf.is_empty() {
let n = try_ready!(this.writer.poll_write(cx, this.buf));
{
let (_, rest) = mem::replace(&mut this.buf, &[]).split_at(n);
this.buf = rest;
}
if n == 0 {
return Poll::Ready(Err(zero_write()))
}
}
Poll::Ready(Ok(()))
}
}