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#![warn(rust_2018_idioms)]
use tokio::io::AsyncWrite;
use tokio_test::{assert_ready, task};
use tokio_util::codec::{Encoder, FramedWrite};
use bytes::{BufMut, BytesMut};
use futures_sink::Sink;
use std::collections::VecDeque;
use std::io::{self, Write};
use std::pin::Pin;
use std::task::Poll::{Pending, Ready};
use std::task::{Context, Poll};
macro_rules! mock {
($($x:expr,)*) => {{
let mut v = VecDeque::new();
v.extend(vec![$($x),*]);
Mock { calls: v }
}};
}
macro_rules! pin {
($id:ident) => {
Pin::new(&mut $id)
};
}
struct U32Encoder;
impl Encoder<u32> for U32Encoder {
type Error = io::Error;
fn encode(&mut self, item: u32, dst: &mut BytesMut) -> io::Result<()> {
// Reserve space
dst.reserve(4);
dst.put_u32(item);
Ok(())
}
}
#[test]
fn write_multi_frame_in_packet() {
let mut task = task::spawn(());
let mock = mock! {
Ok(b"\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x02".to_vec()),
};
let mut framed = FramedWrite::new(mock, U32Encoder);
task.enter(|cx, _| {
assert!(assert_ready!(pin!(framed).poll_ready(cx)).is_ok());
assert!(pin!(framed).start_send(0).is_ok());
assert!(assert_ready!(pin!(framed).poll_ready(cx)).is_ok());
assert!(pin!(framed).start_send(1).is_ok());
assert!(assert_ready!(pin!(framed).poll_ready(cx)).is_ok());
assert!(pin!(framed).start_send(2).is_ok());
// Nothing written yet
assert_eq!(1, framed.get_ref().calls.len());
// Flush the writes
assert!(assert_ready!(pin!(framed).poll_flush(cx)).is_ok());
assert_eq!(0, framed.get_ref().calls.len());
});
}
#[test]
fn write_hits_backpressure() {
const ITER: usize = 2 * 1024;
let mut mock = mock! {
// Block the `ITER`th write
Err(io::Error::new(io::ErrorKind::WouldBlock, "not ready")),
Ok(b"".to_vec()),
};
for i in 0..=ITER {
let mut b = BytesMut::with_capacity(4);
b.put_u32(i as u32);
// Append to the end
match mock.calls.back_mut().unwrap() {
Ok(ref mut data) => {
// Write in 2kb chunks
if data.len() < ITER {
data.extend_from_slice(&b[..]);
continue;
} // else fall through and create a new buffer
}
_ => unreachable!(),
}
// Push a new new chunk
mock.calls.push_back(Ok(b[..].to_vec()));
}
// 1 'wouldblock', 4 * 2KB buffers, 1 b-byte buffer
assert_eq!(mock.calls.len(), 6);
let mut task = task::spawn(());
let mut framed = FramedWrite::new(mock, U32Encoder);
task.enter(|cx, _| {
// Send 8KB. This fills up FramedWrite2 buffer
for i in 0..ITER {
assert!(assert_ready!(pin!(framed).poll_ready(cx)).is_ok());
assert!(pin!(framed).start_send(i as u32).is_ok());
}
// Now we poll_ready which forces a flush. The mock pops the front message
// and decides to block.
assert!(pin!(framed).poll_ready(cx).is_pending());
// We poll again, forcing another flush, which this time succeeds
// The whole 8KB buffer is flushed
assert!(assert_ready!(pin!(framed).poll_ready(cx)).is_ok());
// Send more data. This matches the final message expected by the mock
assert!(pin!(framed).start_send(ITER as u32).is_ok());
// Flush the rest of the buffer
assert!(assert_ready!(pin!(framed).poll_flush(cx)).is_ok());
// Ensure the mock is empty
assert_eq!(0, framed.get_ref().calls.len());
})
}
// // ===== Mock ======
struct Mock {
calls: VecDeque<io::Result<Vec<u8>>>,
}
impl Write for Mock {
fn write(&mut self, src: &[u8]) -> io::Result<usize> {
match self.calls.pop_front() {
Some(Ok(data)) => {
assert!(src.len() >= data.len());
assert_eq!(&data[..], &src[..data.len()]);
Ok(data.len())
}
Some(Err(e)) => Err(e),
None => panic!("unexpected write; {:?}", src),
}
}
fn flush(&mut self) -> io::Result<()> {
Ok(())
}
}
impl AsyncWrite for Mock {
fn poll_write(
self: Pin<&mut Self>,
_cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<Result<usize, io::Error>> {
match Pin::get_mut(self).write(buf) {
Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => Pending,
other => Ready(other),
}
}
fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Result<(), io::Error>> {
match Pin::get_mut(self).flush() {
Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => Pending,
other => Ready(other),
}
}
fn poll_shutdown(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Result<(), io::Error>> {
unimplemented!()
}
}
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