1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
|
#![warn(rust_2018_idioms)]
#![cfg(feature = "full")]
// https://github.com/rust-lang/futures-rs/blob/1803948ff091b4eabf7f3bf39e16bbbdefca5cc8/futures/tests/io_buf_reader.rs
use futures::task::{noop_waker_ref, Context, Poll};
use std::cmp;
use std::io::{self, Cursor};
use std::pin::Pin;
use tokio::io::{
AsyncBufRead, AsyncBufReadExt, AsyncRead, AsyncReadExt, AsyncSeek, AsyncSeekExt, AsyncWriteExt,
BufReader, ReadBuf, SeekFrom,
};
use tokio_test::task::spawn;
use tokio_test::{assert_pending, assert_ready};
macro_rules! run_fill_buf {
($reader:expr) => {{
let mut cx = Context::from_waker(noop_waker_ref());
loop {
if let Poll::Ready(x) = Pin::new(&mut $reader).poll_fill_buf(&mut cx) {
break x;
}
}
}};
}
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 ReadBuf<'_>,
) -> Poll<io::Result<()>> {
if self.ready_read {
self.ready_read = false;
Pin::new(&mut self.inner).poll_read(cx, buf)
} else {
self.ready_read = true;
cx.waker().wake_by_ref();
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..];
}
}
#[tokio::test]
async fn test_buffered_reader() {
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);
}
#[tokio::test]
async fn test_buffered_reader_seek() {
let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
let mut reader = BufReader::with_capacity(2, Cursor::new(inner));
assert_eq!(reader.seek(SeekFrom::Start(3)).await.unwrap(), 3);
assert_eq!(run_fill_buf!(reader).unwrap(), &[0, 1][..]);
assert!(reader.seek(SeekFrom::Current(i64::MIN)).await.is_err());
assert_eq!(run_fill_buf!(reader).unwrap(), &[0, 1][..]);
assert_eq!(reader.seek(SeekFrom::Current(1)).await.unwrap(), 4);
assert_eq!(run_fill_buf!(reader).unwrap(), &[1, 2][..]);
Pin::new(&mut reader).consume(1);
assert_eq!(reader.seek(SeekFrom::Current(-2)).await.unwrap(), 3);
}
#[tokio::test]
async fn test_buffered_reader_seek_underflow() {
// gimmick reader that yields its position modulo 256 for each byte
struct PositionReader {
pos: u64,
}
impl AsyncRead for PositionReader {
fn poll_read(
mut self: Pin<&mut Self>,
_: &mut Context<'_>,
buf: &mut ReadBuf<'_>,
) -> Poll<io::Result<()>> {
let b = buf.initialize_unfilled();
let len = b.len();
for x in b {
*x = self.pos as u8;
self.pos = self.pos.wrapping_add(1);
}
buf.advance(len);
Poll::Ready(Ok(()))
}
}
impl AsyncSeek for PositionReader {
fn start_seek(mut self: Pin<&mut Self>, pos: SeekFrom) -> io::Result<()> {
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(())
}
fn poll_complete(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<u64>> {
Poll::Ready(Ok(self.pos))
}
}
let mut reader = BufReader::with_capacity(5, PositionReader { pos: 0 });
assert_eq!(run_fill_buf!(reader).unwrap(), &[0, 1, 2, 3, 4][..]);
assert_eq!(reader.seek(SeekFrom::End(-5)).await.unwrap(), u64::MAX - 5);
assert_eq!(run_fill_buf!(reader).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!(run_fill_buf!(reader).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().pos, expected);
}
#[tokio::test]
async fn test_short_reads() {
/// A dummy reader intended at testing short-reads propagation.
struct ShortReader {
lengths: Vec<usize>,
}
impl AsyncRead for ShortReader {
fn poll_read(
mut self: Pin<&mut Self>,
_: &mut Context<'_>,
buf: &mut ReadBuf<'_>,
) -> Poll<io::Result<()>> {
if !self.lengths.is_empty() {
buf.advance(self.lengths.remove(0));
}
Poll::Ready(Ok(()))
}
}
let inner = ShortReader {
lengths: vec![0, 1, 2, 0, 1, 0],
};
let mut reader = BufReader::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);
}
#[tokio::test]
async 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 = 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);
}
#[tokio::test]
async 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();
reader.read_until(3, &mut v).await.unwrap();
assert_eq!(v, [0, 1, 2, 3]);
v.clear();
reader.read_until(1, &mut v).await.unwrap();
assert_eq!(v, [1]);
v.clear();
reader.read_until(8, &mut v).await.unwrap();
assert_eq!(v, [0]);
v.clear();
reader.read_until(9, &mut v).await.unwrap();
assert_eq!(v, []);
}
// https://github.com/rust-lang/futures-rs/pull/1573#discussion_r281162309
#[tokio::test]
async fn maybe_pending_seek() {
struct MaybePendingSeek<'a> {
inner: Cursor<&'a [u8]>,
ready: bool,
seek_res: Option<io::Result<()>>,
}
impl<'a> MaybePendingSeek<'a> {
fn new(inner: &'a [u8]) -> Self {
Self {
inner: Cursor::new(inner),
ready: true,
seek_res: None,
}
}
}
impl AsyncRead for MaybePendingSeek<'_> {
fn poll_read(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut ReadBuf<'_>,
) -> Poll<io::Result<()>> {
Pin::new(&mut self.inner).poll_read(cx, buf)
}
}
impl AsyncBufRead for MaybePendingSeek<'_> {
fn poll_fill_buf(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<io::Result<&[u8]>> {
let this: *mut Self = &mut *self as *mut _;
Pin::new(&mut unsafe { &mut *this }.inner).poll_fill_buf(cx)
}
fn consume(mut self: Pin<&mut Self>, amt: usize) {
Pin::new(&mut self.inner).consume(amt)
}
}
impl AsyncSeek for MaybePendingSeek<'_> {
fn start_seek(mut self: Pin<&mut Self>, pos: SeekFrom) -> io::Result<()> {
self.seek_res = Some(Pin::new(&mut self.inner).start_seek(pos));
Ok(())
}
fn poll_complete(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<u64>> {
if self.ready {
self.ready = false;
self.seek_res.take().unwrap_or(Ok(()))?;
Pin::new(&mut self.inner).poll_complete(cx)
} else {
self.ready = true;
cx.waker().wake_by_ref();
Poll::Pending
}
}
}
let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
let mut reader = BufReader::with_capacity(2, MaybePendingSeek::new(inner));
assert_eq!(reader.seek(SeekFrom::Current(3)).await.unwrap(), 3);
assert_eq!(run_fill_buf!(reader).unwrap(), &[0, 1][..]);
assert!(reader.seek(SeekFrom::Current(i64::MIN)).await.is_err());
assert_eq!(run_fill_buf!(reader).unwrap(), &[0, 1][..]);
assert_eq!(reader.seek(SeekFrom::Current(1)).await.unwrap(), 4);
assert_eq!(run_fill_buf!(reader).unwrap(), &[1, 2][..]);
Pin::new(&mut reader).consume(1);
assert_eq!(reader.seek(SeekFrom::Current(-2)).await.unwrap(), 3);
}
// This tests the AsyncBufReadExt::fill_buf wrapper.
#[tokio::test]
async fn test_fill_buf_wrapper() {
let (mut write, read) = tokio::io::duplex(16);
let mut read = BufReader::new(read);
write.write_all(b"hello world").await.unwrap();
assert_eq!(read.fill_buf().await.unwrap(), b"hello world");
read.consume(b"hello ".len());
assert_eq!(read.fill_buf().await.unwrap(), b"world");
assert_eq!(read.fill_buf().await.unwrap(), b"world");
read.consume(b"world".len());
let mut fill = spawn(read.fill_buf());
assert_pending!(fill.poll());
write.write_all(b"foo bar").await.unwrap();
assert_eq!(assert_ready!(fill.poll()).unwrap(), b"foo bar");
drop(fill);
drop(write);
assert_eq!(read.fill_buf().await.unwrap(), b"foo bar");
read.consume(b"foo bar".len());
assert_eq!(read.fill_buf().await.unwrap(), b"");
}
|
