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
use core::marker::Unpin;
use core::pin::Pin;
use futures_core::stream::Stream;
use futures_core::task::{LocalWaker, Poll};
use pin_utils::{unsafe_pinned, unsafe_unpinned};
#[derive(Debug)]
#[must_use = "streams do nothing unless polled"]
pub struct Map<St, F> {
stream: St,
f: F,
}
impl<St: Unpin, F> Unpin for Map<St, F> {}
impl<St, T, F> Map<St, F>
where St: Stream,
F: FnMut(St::Item) -> T,
{
unsafe_pinned!(stream: St);
unsafe_unpinned!(f: F);
pub(super) fn new(stream: St, f: F) -> Map<St, F> {
Map { stream, f }
}
pub fn get_ref(&self) -> &St {
&self.stream
}
pub fn get_mut(&mut self) -> &mut St {
&mut self.stream
}
pub fn into_inner(self) -> St {
self.stream
}
}
impl<St, F, T> Stream for Map<St, F>
where St: Stream,
F: FnMut(St::Item) -> T,
{
type Item = T;
fn poll_next(
mut self: Pin<&mut Self>,
lw: &LocalWaker
) -> Poll<Option<T>> {
let option = ready!(self.stream().poll_next(lw));
Poll::Ready(option.map(self.f()))
}
}