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
use crate::io::util::{BufReader, BufWriter};
use crate::io::{AsyncBufRead, AsyncRead, AsyncWrite};
use pin_project_lite::pin_project;
use std::io;
use std::mem::MaybeUninit;
use std::pin::Pin;
use std::task::{Context, Poll};
pin_project! {
/// Wraps a type that is [`AsyncWrite`] and [`AsyncRead`], and buffers its input and output.
///
/// It can be excessively inefficient to work directly with something that implements [`AsyncWrite`]
/// and [`AsyncRead`]. For example, every `write`, however small, has to traverse the syscall
/// interface, and similarly, every read has to do the same. The [`BufWriter`] and [`BufReader`]
/// types aid with these problems respectively, but do so in only one direction. `BufStream` wraps
/// one in the other so that both directions are buffered. See their documentation for details.
#[derive(Debug)]
#[cfg_attr(docsrs, doc(cfg(feature = "io-util")))]
pub struct BufStream<RW> {
#[pin]
inner: BufReader<BufWriter<RW>>,
}
}
impl<RW: AsyncRead + AsyncWrite> BufStream<RW> {
/// Wraps a type in both [`BufWriter`] and [`BufReader`].
///
/// See the documentation for those types and [`BufStream`] for details.
pub fn new(stream: RW) -> BufStream<RW> {
BufStream {
inner: BufReader::new(BufWriter::new(stream)),
}
}
/// Creates a `BufStream` with the specified [`BufReader`] capacity and [`BufWriter`]
/// capacity.
///
/// See the documentation for those types and [`BufStream`] for details.
pub fn with_capacity(
reader_capacity: usize,
writer_capacity: usize,
stream: RW,
) -> BufStream<RW> {
BufStream {
inner: BufReader::with_capacity(
reader_capacity,
BufWriter::with_capacity(writer_capacity, stream),
),
}
}
/// Gets a reference to the underlying I/O object.
///
/// It is inadvisable to directly read from the underlying I/O object.
pub fn get_ref(&self) -> &RW {
self.inner.get_ref().get_ref()
}
/// Gets a mutable reference to the underlying I/O object.
///
/// It is inadvisable to directly read from the underlying I/O object.
pub fn get_mut(&mut self) -> &mut RW {
self.inner.get_mut().get_mut()
}
/// Gets a pinned mutable reference to the underlying I/O object.
///
/// It is inadvisable to directly read from the underlying I/O object.
pub fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut RW> {
self.project().inner.get_pin_mut().get_pin_mut()
}
/// Consumes this `BufStream`, returning the underlying I/O object.
///
/// Note that any leftover data in the internal buffer is lost.
pub fn into_inner(self) -> RW {
self.inner.into_inner().into_inner()
}
}
impl<RW> From<BufReader<BufWriter<RW>>> for BufStream<RW> {
fn from(b: BufReader<BufWriter<RW>>) -> Self {
BufStream { inner: b }
}
}
impl<RW> From<BufWriter<BufReader<RW>>> for BufStream<RW> {
fn from(b: BufWriter<BufReader<RW>>) -> Self {
// we need to "invert" the reader and writer
let BufWriter {
inner:
BufReader {
inner,
buf: rbuf,
pos,
cap,
},
buf: wbuf,
written,
} = b;
BufStream {
inner: BufReader {
inner: BufWriter {
inner,
buf: wbuf,
written,
},
buf: rbuf,
pos,
cap,
},
}
}
}
impl<RW: AsyncRead + AsyncWrite> AsyncWrite for BufStream<RW> {
fn poll_write(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
self.project().inner.poll_write(cx, buf)
}
fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
self.project().inner.poll_flush(cx)
}
fn poll_shutdown(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
self.project().inner.poll_shutdown(cx)
}
}
impl<RW: AsyncRead + AsyncWrite> AsyncRead for BufStream<RW> {
fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8],
) -> Poll<io::Result<usize>> {
self.project().inner.poll_read(cx, buf)
}
// we can't skip unconditionally because of the large buffer case in read.
unsafe fn prepare_uninitialized_buffer(&self, buf: &mut [MaybeUninit<u8>]) -> bool {
self.inner.prepare_uninitialized_buffer(buf)
}
}
impl<RW: AsyncRead + AsyncWrite> AsyncBufRead for BufStream<RW> {
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)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn assert_unpin() {
crate::is_unpin::<BufStream<()>>();
}
}