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
use crate::io::{AsyncRead, AsyncWrite};
use std::future::Future;
use std::io;
use std::pin::Pin;
use std::task::{Context, Poll};
cfg_io_util! {
#[derive(Debug)]
#[must_use = "futures do nothing unless you `.await` or poll them"]
pub struct Copy<'a, R: ?Sized, W: ?Sized> {
reader: &'a mut R,
read_done: bool,
writer: &'a mut W,
pos: usize,
cap: usize,
amt: u64,
buf: Box<[u8]>,
}
pub fn copy<'a, R, W>(reader: &'a mut R, writer: &'a mut W) -> Copy<'a, R, W>
where
R: AsyncRead + Unpin + ?Sized,
W: AsyncWrite + Unpin + ?Sized,
{
Copy {
reader,
read_done: false,
writer,
amt: 0,
pos: 0,
cap: 0,
buf: vec![0; 2048].into_boxed_slice(),
}
}
}
impl<R, W> Future for Copy<'_, R, W>
where
R: AsyncRead + Unpin + ?Sized,
W: AsyncWrite + Unpin + ?Sized,
{
type Output = io::Result<u64>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<u64>> {
loop {
if self.pos == self.cap && !self.read_done {
let me = &mut *self;
let n = ready!(Pin::new(&mut *me.reader).poll_read(cx, &mut me.buf))?;
if n == 0 {
self.read_done = true;
} else {
self.pos = 0;
self.cap = n;
}
}
while self.pos < self.cap {
let me = &mut *self;
let i = ready!(Pin::new(&mut *me.writer).poll_write(cx, &me.buf[me.pos..me.cap]))?;
if i == 0 {
return Poll::Ready(Err(io::Error::new(
io::ErrorKind::WriteZero,
"write zero byte into writer",
)));
} else {
self.pos += i;
self.amt += i as u64;
}
}
if self.pos == self.cap && self.read_done {
let me = &mut *self;
ready!(Pin::new(&mut *me.writer).poll_flush(cx))?;
return Poll::Ready(Ok(self.amt));
}
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn assert_unpin() {
use std::marker::PhantomPinned;
crate::is_unpin::<Copy<'_, PhantomPinned, PhantomPinned>>();
}
}