Source code
Revision control
Copy as Markdown
Other Tools
use futures::executor::block_on;
use futures::future::{Future, FutureExt};
use futures::io::{
AllowStdIo, AsyncBufRead, AsyncBufReadExt, AsyncRead, AsyncReadExt, AsyncSeek, AsyncSeekExt,
BufReader, SeekFrom,
};
use futures::pin_mut;
use futures::task::{Context, Poll};
use futures_test::task::noop_context;
use pin_project::pin_project;
use std::cmp;
use std::io;
use std::pin::Pin;
// helper for maybe_pending_* tests
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;
}
}
}
#[pin_project(!Unpin)]
struct Cursor<T> {
#[pin]
inner: futures::io::Cursor<T>,
}
impl<T> Cursor<T> {
fn new(inner: T) -> Self {
Self { inner: futures::io::Cursor::new(inner) }
}
}
impl AsyncRead for Cursor<&[u8]> {
fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8],
) -> Poll<io::Result<usize>> {
self.project().inner.poll_read(cx, buf)
}
}
impl AsyncBufRead for Cursor<&[u8]> {
fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<&[u8]>> {
self.project().inner.poll_fill_buf(cx)
}
fn consume(self: Pin<&mut Self>, amt: usize) {
self.project().inner.consume(amt)
}
}
impl AsyncSeek for Cursor<&[u8]> {
fn poll_seek(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
pos: SeekFrom,
) -> Poll<io::Result<u64>> {
self.project().inner.poll_seek(cx, pos)
}
}
struct MaybePending<'a> {
inner: &'a [u8],
ready_read: bool,
ready_fill_buf: bool,
}
impl<'a> MaybePending<'a> {
fn new(inner: &'a [u8]) -> Self {
Self { inner, ready_read: false, ready_fill_buf: false }
}
}
impl AsyncRead for MaybePending<'_> {
fn poll_read(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8],
) -> Poll<io::Result<usize>> {
if self.ready_read {
self.ready_read = false;
Pin::new(&mut self.inner).poll_read(cx, buf)
} else {
self.ready_read = true;
Poll::Pending
}
}
}
impl AsyncBufRead for MaybePending<'_> {
fn poll_fill_buf(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<&[u8]>> {
if self.ready_fill_buf {
self.ready_fill_buf = false;
if self.inner.is_empty() {
return Poll::Ready(Ok(&[]));
}
let len = cmp::min(2, self.inner.len());
Poll::Ready(Ok(&self.inner[0..len]))
} else {
self.ready_fill_buf = true;
Poll::Pending
}
}
fn consume(mut self: Pin<&mut Self>, amt: usize) {
self.inner = &self.inner[amt..];
}
}
#[test]
fn test_buffered_reader() {
block_on(async {
let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
let mut reader = BufReader::with_capacity(2, inner);
let mut buf = [0, 0, 0];
let nread = reader.read(&mut buf).await.unwrap();
assert_eq!(nread, 3);
assert_eq!(buf, [5, 6, 7]);
assert_eq!(reader.buffer(), []);
let mut buf = [0, 0];
let nread = reader.read(&mut buf).await.unwrap();
assert_eq!(nread, 2);
assert_eq!(buf, [0, 1]);
assert_eq!(reader.buffer(), []);
let mut buf = [0];
let nread = reader.read(&mut buf).await.unwrap();
assert_eq!(nread, 1);
assert_eq!(buf, [2]);
assert_eq!(reader.buffer(), [3]);
let mut buf = [0, 0, 0];
let nread = reader.read(&mut buf).await.unwrap();
assert_eq!(nread, 1);
assert_eq!(buf, [3, 0, 0]);
assert_eq!(reader.buffer(), []);
let nread = reader.read(&mut buf).await.unwrap();
assert_eq!(nread, 1);
assert_eq!(buf, [4, 0, 0]);
assert_eq!(reader.buffer(), []);
assert_eq!(reader.read(&mut buf).await.unwrap(), 0);
});
}
#[test]
fn test_buffered_reader_seek() {
block_on(async {
let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
let reader = BufReader::with_capacity(2, Cursor::new(inner));
pin_mut!(reader);
assert_eq!(reader.seek(SeekFrom::Start(3)).await.unwrap(), 3);
assert_eq!(reader.as_mut().fill_buf().await.unwrap(), &[0, 1][..]);
assert!(reader.seek(SeekFrom::Current(i64::MIN)).await.is_err());
assert_eq!(reader.as_mut().fill_buf().await.unwrap(), &[0, 1][..]);
assert_eq!(reader.seek(SeekFrom::Current(1)).await.unwrap(), 4);
assert_eq!(reader.as_mut().fill_buf().await.unwrap(), &[1, 2][..]);
reader.as_mut().consume(1);
assert_eq!(reader.seek(SeekFrom::Current(-2)).await.unwrap(), 3);
});
}
#[test]
fn test_buffered_reader_seek_relative() {
block_on(async {
let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
let reader = BufReader::with_capacity(2, Cursor::new(inner));
pin_mut!(reader);
assert!(reader.as_mut().seek_relative(3).await.is_ok());
assert_eq!(reader.as_mut().fill_buf().await.unwrap(), &[0, 1][..]);
assert!(reader.as_mut().seek_relative(0).await.is_ok());
assert_eq!(reader.as_mut().fill_buf().await.unwrap(), &[0, 1][..]);
assert!(reader.as_mut().seek_relative(1).await.is_ok());
assert_eq!(reader.as_mut().fill_buf().await.unwrap(), &[1][..]);
assert!(reader.as_mut().seek_relative(-1).await.is_ok());
assert_eq!(reader.as_mut().fill_buf().await.unwrap(), &[0, 1][..]);
assert!(reader.as_mut().seek_relative(2).await.is_ok());
assert_eq!(reader.as_mut().fill_buf().await.unwrap(), &[2, 3][..]);
});
}
#[test]
fn test_buffered_reader_invalidated_after_read() {
block_on(async {
let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
let reader = BufReader::with_capacity(3, Cursor::new(inner));
pin_mut!(reader);
assert_eq!(reader.as_mut().fill_buf().await.unwrap(), &[5, 6, 7][..]);
reader.as_mut().consume(3);
let mut buffer = [0, 0, 0, 0, 0];
assert_eq!(reader.read(&mut buffer).await.unwrap(), 5);
assert_eq!(buffer, [0, 1, 2, 3, 4]);
assert!(reader.as_mut().seek_relative(-2).await.is_ok());
let mut buffer = [0, 0];
assert_eq!(reader.read(&mut buffer).await.unwrap(), 2);
assert_eq!(buffer, [3, 4]);
});
}
#[test]
fn test_buffered_reader_invalidated_after_seek() {
block_on(async {
let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
let reader = BufReader::with_capacity(3, Cursor::new(inner));
pin_mut!(reader);
assert_eq!(reader.as_mut().fill_buf().await.unwrap(), &[5, 6, 7][..]);
reader.as_mut().consume(3);
assert!(reader.seek(SeekFrom::Current(5)).await.is_ok());
assert!(reader.as_mut().seek_relative(-2).await.is_ok());
let mut buffer = [0, 0];
assert_eq!(reader.read(&mut buffer).await.unwrap(), 2);
assert_eq!(buffer, [3, 4]);
});
}
#[test]
fn test_buffered_reader_seek_underflow() {
// gimmick reader that yields its position modulo 256 for each byte
struct PositionReader {
pos: u64,
}
impl io::Read for PositionReader {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
let len = buf.len();
for x in buf {
*x = self.pos as u8;
self.pos = self.pos.wrapping_add(1);
}
Ok(len)
}
}
impl io::Seek for PositionReader {
fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
match pos {
SeekFrom::Start(n) => {
self.pos = n;
}
SeekFrom::Current(n) => {
self.pos = self.pos.wrapping_add(n as u64);
}
SeekFrom::End(n) => {
self.pos = u64::MAX.wrapping_add(n as u64);
}
}
Ok(self.pos)
}
}
block_on(async {
let reader = BufReader::with_capacity(5, AllowStdIo::new(PositionReader { pos: 0 }));
pin_mut!(reader);
assert_eq!(reader.as_mut().fill_buf().await.unwrap(), &[0, 1, 2, 3, 4][..]);
assert_eq!(reader.seek(SeekFrom::End(-5)).await.unwrap(), u64::MAX - 5);
assert_eq!(reader.as_mut().fill_buf().await.unwrap().len(), 5);
// the following seek will require two underlying seeks
let expected = 9_223_372_036_854_775_802;
assert_eq!(reader.seek(SeekFrom::Current(i64::MIN)).await.unwrap(), expected);
assert_eq!(reader.as_mut().fill_buf().await.unwrap().len(), 5);
// seeking to 0 should empty the buffer.
assert_eq!(reader.seek(SeekFrom::Current(0)).await.unwrap(), expected);
assert_eq!(reader.get_ref().get_ref().pos, expected);
});
}
#[test]
fn test_short_reads() {
/// A dummy reader intended at testing short-reads propagation.
struct ShortReader {
lengths: Vec<usize>,
}
impl io::Read for ShortReader {
fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
if self.lengths.is_empty() {
Ok(0)
} else {
Ok(self.lengths.remove(0))
}
}
}
block_on(async {
let inner = ShortReader { lengths: vec![0, 1, 2, 0, 1, 0] };
let mut reader = BufReader::new(AllowStdIo::new(inner));
let mut buf = [0, 0];
assert_eq!(reader.read(&mut buf).await.unwrap(), 0);
assert_eq!(reader.read(&mut buf).await.unwrap(), 1);
assert_eq!(reader.read(&mut buf).await.unwrap(), 2);
assert_eq!(reader.read(&mut buf).await.unwrap(), 0);
assert_eq!(reader.read(&mut buf).await.unwrap(), 1);
assert_eq!(reader.read(&mut buf).await.unwrap(), 0);
assert_eq!(reader.read(&mut buf).await.unwrap(), 0);
});
}
#[test]
fn maybe_pending() {
let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
let mut reader = BufReader::with_capacity(2, MaybePending::new(inner));
let mut buf = [0, 0, 0];
let nread = run(reader.read(&mut buf));
assert_eq!(nread.unwrap(), 3);
assert_eq!(buf, [5, 6, 7]);
assert_eq!(reader.buffer(), []);
let mut buf = [0, 0];
let nread = run(reader.read(&mut buf));
assert_eq!(nread.unwrap(), 2);
assert_eq!(buf, [0, 1]);
assert_eq!(reader.buffer(), []);
let mut buf = [0];
let nread = run(reader.read(&mut buf));
assert_eq!(nread.unwrap(), 1);
assert_eq!(buf, [2]);
assert_eq!(reader.buffer(), [3]);
let mut buf = [0, 0, 0];
let nread = run(reader.read(&mut buf));
assert_eq!(nread.unwrap(), 1);
assert_eq!(buf, [3, 0, 0]);
assert_eq!(reader.buffer(), []);
let nread = run(reader.read(&mut buf));
assert_eq!(nread.unwrap(), 1);
assert_eq!(buf, [4, 0, 0]);
assert_eq!(reader.buffer(), []);
assert_eq!(run(reader.read(&mut buf)).unwrap(), 0);
}
#[test]
fn maybe_pending_buf_read() {
let inner = MaybePending::new(&[0, 1, 2, 3, 1, 0]);
let mut reader = BufReader::with_capacity(2, inner);
let mut v = Vec::new();
run(reader.read_until(3, &mut v)).unwrap();
assert_eq!(v, [0, 1, 2, 3]);
v.clear();
run(reader.read_until(1, &mut v)).unwrap();
assert_eq!(v, [1]);
v.clear();
run(reader.read_until(8, &mut v)).unwrap();
assert_eq!(v, [0]);
v.clear();
run(reader.read_until(9, &mut v)).unwrap();
assert_eq!(v, []);
}
#[test]
fn maybe_pending_seek() {
#[pin_project]
struct MaybePendingSeek<'a> {
#[pin]
inner: Cursor<&'a [u8]>,
ready: bool,
}
impl<'a> MaybePendingSeek<'a> {
fn new(inner: &'a [u8]) -> Self {
Self { inner: Cursor::new(inner), ready: true }
}
}
impl AsyncRead for MaybePendingSeek<'_> {
fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8],
) -> Poll<io::Result<usize>> {
self.project().inner.poll_read(cx, buf)
}
}
impl AsyncBufRead for MaybePendingSeek<'_> {
fn poll_fill_buf(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<&[u8]>> {
self.project().inner.poll_fill_buf(cx)
}
fn consume(self: Pin<&mut Self>, amt: usize) {
self.project().inner.consume(amt)
}
}
impl AsyncSeek for MaybePendingSeek<'_> {
fn poll_seek(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
pos: SeekFrom,
) -> Poll<io::Result<u64>> {
if self.ready {
*self.as_mut().project().ready = false;
self.project().inner.poll_seek(cx, pos)
} else {
*self.project().ready = true;
Poll::Pending
}
}
}
let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
let reader = BufReader::with_capacity(2, MaybePendingSeek::new(inner));
pin_mut!(reader);
assert_eq!(run(reader.seek(SeekFrom::Current(3))).ok(), Some(3));
assert_eq!(run(reader.as_mut().fill_buf()).ok(), Some(&[0, 1][..]));
assert_eq!(run(reader.seek(SeekFrom::Current(i64::MIN))).ok(), None);
assert_eq!(run(reader.as_mut().fill_buf()).ok(), Some(&[0, 1][..]));
assert_eq!(run(reader.seek(SeekFrom::Current(1))).ok(), Some(4));
assert_eq!(run(reader.as_mut().fill_buf()).ok(), Some(&[1, 2][..]));
Pin::new(&mut reader).consume(1);
assert_eq!(run(reader.seek(SeekFrom::Current(-2))).ok(), Some(3));
}