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use futures::executor::block_on;
use futures::future::{Future, FutureExt};
use futures::io::{
AsyncSeek, AsyncSeekExt, AsyncWrite, AsyncWriteExt, BufWriter, Cursor, SeekFrom,
};
use futures::task::{Context, Poll};
use futures_test::task::noop_context;
use std::io;
use std::pin::Pin;
struct MaybePending {
inner: Vec<u8>,
ready: bool,
}
impl MaybePending {
fn new(inner: Vec<u8>) -> Self {
Self { inner, ready: false }
}
}
impl AsyncWrite for MaybePending {
fn poll_write(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
if self.ready {
self.ready = false;
Pin::new(&mut self.inner).poll_write(cx, buf)
} else {
self.ready = true;
Poll::Pending
}
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
Pin::new(&mut self.inner).poll_flush(cx)
}
fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
Pin::new(&mut self.inner).poll_close(cx)
}
}
fn run<F: Future + Unpin>(mut f: F) -> F::Output {
let mut cx = noop_context();
loop {
if let Poll::Ready(x) = f.poll_unpin(&mut cx) {
return x;
}
}
}
#[test]
fn buf_writer() {
let mut writer = BufWriter::with_capacity(2, Vec::new());
block_on(writer.write(&[0, 1])).unwrap();
assert_eq!(writer.buffer(), []);
assert_eq!(*writer.get_ref(), [0, 1]);
block_on(writer.write(&[2])).unwrap();
assert_eq!(writer.buffer(), [2]);
assert_eq!(*writer.get_ref(), [0, 1]);
block_on(writer.write(&[3])).unwrap();
assert_eq!(writer.buffer(), [2, 3]);
assert_eq!(*writer.get_ref(), [0, 1]);
block_on(writer.flush()).unwrap();
assert_eq!(writer.buffer(), []);
assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
block_on(writer.write(&[4])).unwrap();
block_on(writer.write(&[5])).unwrap();
assert_eq!(writer.buffer(), [4, 5]);
assert_eq!(*writer.get_ref(), [0, 1, 2, 3]);
block_on(writer.write(&[6])).unwrap();
assert_eq!(writer.buffer(), [6]);
assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5]);
block_on(writer.write(&[7, 8])).unwrap();
assert_eq!(writer.buffer(), []);
assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8]);
block_on(writer.write(&[9, 10, 11])).unwrap();
assert_eq!(writer.buffer(), []);
assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
block_on(writer.flush()).unwrap();
assert_eq!(writer.buffer(), []);
assert_eq!(*writer.get_ref(), [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
}
#[test]
fn buf_writer_inner_flushes() {
let mut w = BufWriter::with_capacity(3, Vec::new());
block_on(w.write(&[0, 1])).unwrap();
assert_eq!(*w.get_ref(), []);
block_on(w.flush()).unwrap();
let w = w.into_inner();
assert_eq!(w, [0, 1]);
}
#[test]
fn buf_writer_seek() {
// use `Vec::new` instead of `vec![0; 8]`.
let mut w = BufWriter::with_capacity(3, Cursor::new(vec![0; 8]));
block_on(w.write_all(&[0, 1, 2, 3, 4, 5])).unwrap();
block_on(w.write_all(&[6, 7])).unwrap();
assert_eq!(block_on(w.seek(SeekFrom::Current(0))).ok(), Some(8));
assert_eq!(&w.get_ref().get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
assert_eq!(block_on(w.seek(SeekFrom::Start(2))).ok(), Some(2));
block_on(w.write_all(&[8, 9])).unwrap();
block_on(w.flush()).unwrap();
assert_eq!(&w.into_inner().into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
}
#[test]
fn maybe_pending_buf_writer() {
let mut writer = BufWriter::with_capacity(2, MaybePending::new(Vec::new()));
run(writer.write(&[0, 1])).unwrap();
assert_eq!(writer.buffer(), []);
assert_eq!(&writer.get_ref().inner, &[0, 1]);
run(writer.write(&[2])).unwrap();
assert_eq!(writer.buffer(), [2]);
assert_eq!(&writer.get_ref().inner, &[0, 1]);
run(writer.write(&[3])).unwrap();
assert_eq!(writer.buffer(), [2, 3]);
assert_eq!(&writer.get_ref().inner, &[0, 1]);
run(writer.flush()).unwrap();
assert_eq!(writer.buffer(), []);
assert_eq!(&writer.get_ref().inner, &[0, 1, 2, 3]);
run(writer.write(&[4])).unwrap();
run(writer.write(&[5])).unwrap();
assert_eq!(writer.buffer(), [4, 5]);
assert_eq!(&writer.get_ref().inner, &[0, 1, 2, 3]);
run(writer.write(&[6])).unwrap();
assert_eq!(writer.buffer(), [6]);
assert_eq!(writer.get_ref().inner, &[0, 1, 2, 3, 4, 5]);
run(writer.write(&[7, 8])).unwrap();
assert_eq!(writer.buffer(), []);
assert_eq!(writer.get_ref().inner, &[0, 1, 2, 3, 4, 5, 6, 7, 8]);
run(writer.write(&[9, 10, 11])).unwrap();
assert_eq!(writer.buffer(), []);
assert_eq!(writer.get_ref().inner, &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
run(writer.flush()).unwrap();
assert_eq!(writer.buffer(), []);
assert_eq!(&writer.get_ref().inner, &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
}
#[test]
fn maybe_pending_buf_writer_inner_flushes() {
let mut w = BufWriter::with_capacity(3, MaybePending::new(Vec::new()));
run(w.write(&[0, 1])).unwrap();
assert_eq!(&w.get_ref().inner, &[]);
run(w.flush()).unwrap();
let w = w.into_inner().inner;
assert_eq!(w, [0, 1]);
}
#[test]
fn maybe_pending_buf_writer_seek() {
struct MaybePendingSeek {
inner: Cursor<Vec<u8>>,
ready_write: bool,
ready_seek: bool,
}
impl MaybePendingSeek {
fn new(inner: Vec<u8>) -> Self {
Self { inner: Cursor::new(inner), ready_write: false, ready_seek: false }
}
}
impl AsyncWrite for MaybePendingSeek {
fn poll_write(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
if self.ready_write {
self.ready_write = false;
Pin::new(&mut self.inner).poll_write(cx, buf)
} else {
self.ready_write = true;
Poll::Pending
}
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
Pin::new(&mut self.inner).poll_flush(cx)
}
fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
Pin::new(&mut self.inner).poll_close(cx)
}
}
impl AsyncSeek for MaybePendingSeek {
fn poll_seek(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
pos: SeekFrom,
) -> Poll<io::Result<u64>> {
if self.ready_seek {
self.ready_seek = false;
Pin::new(&mut self.inner).poll_seek(cx, pos)
} else {
self.ready_seek = true;
Poll::Pending
}
}
}
// use `Vec::new` instead of `vec![0; 8]`.
let mut w = BufWriter::with_capacity(3, MaybePendingSeek::new(vec![0; 8]));
run(w.write_all(&[0, 1, 2, 3, 4, 5])).unwrap();
run(w.write_all(&[6, 7])).unwrap();
assert_eq!(run(w.seek(SeekFrom::Current(0))).ok(), Some(8));
assert_eq!(&w.get_ref().inner.get_ref()[..], &[0, 1, 2, 3, 4, 5, 6, 7][..]);
assert_eq!(run(w.seek(SeekFrom::Start(2))).ok(), Some(2));
run(w.write_all(&[8, 9])).unwrap();
run(w.flush()).unwrap();
assert_eq!(&w.into_inner().inner.into_inner()[..], &[0, 1, 8, 9, 4, 5, 6, 7]);
}