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
use futures_core::{Async, Poll, Stream};
use futures_core::task;
use futures_sink::{Sink};
#[derive(Debug)]
#[must_use = "streams do nothing unless polled"]
pub struct Map<S, F> {
stream: S,
f: F,
}
pub fn new<S, U, F>(s: S, f: F) -> Map<S, F>
where S: Stream,
F: FnMut(S::Item) -> U,
{
Map {
stream: s,
f: f,
}
}
impl<S, F> Map<S, F> {
pub fn get_ref(&self) -> &S {
&self.stream
}
pub fn get_mut(&mut self) -> &mut S {
&mut self.stream
}
pub fn into_inner(self) -> S {
self.stream
}
}
impl<S, F> Sink for Map<S, F>
where S: Sink
{
type SinkItem = S::SinkItem;
type SinkError = S::SinkError;
delegate_sink!(stream);
}
impl<S, F, U> Stream for Map<S, F>
where S: Stream,
F: FnMut(S::Item) -> U,
{
type Item = U;
type Error = S::Error;
fn poll_next(&mut self, cx: &mut task::Context) -> Poll<Option<U>, S::Error> {
let option = try_ready!(self.stream.poll_next(cx));
Ok(Async::Ready(option.map(&mut self.f)))
}
}