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
use core::pin::Pin;
use futures_core::stream::{FusedStream, Stream};
use futures_core::task::{Context, Poll};
#[cfg(feature = "sink")]
use futures_sink::Sink;
use pin_utils::{unsafe_pinned, unsafe_unpinned};
#[derive(Debug)]
#[must_use = "streams do nothing unless polled"]
pub struct Enumerate<St> {
stream: St,
count: usize,
}
impl<St: Unpin> Unpin for Enumerate<St> {}
impl<St: Stream> Enumerate<St> {
unsafe_pinned!(stream: St);
unsafe_unpinned!(count: usize);
pub(super) fn new(stream: St) -> Enumerate<St> {
Enumerate {
stream,
count: 0,
}
}
pub fn get_ref(&self) -> &St {
&self.stream
}
pub fn get_mut(&mut self) -> &mut St {
&mut self.stream
}
pub fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut St> {
self.stream()
}
pub fn into_inner(self) -> St {
self.stream
}
}
impl<St: Stream + FusedStream> FusedStream for Enumerate<St> {
fn is_terminated(&self) -> bool {
self.stream.is_terminated()
}
}
impl<St: Stream> Stream for Enumerate<St> {
type Item = (usize, St::Item);
fn poll_next(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Self::Item>> {
match ready!(self.as_mut().stream().poll_next(cx)) {
Some(item) => {
let count = self.count;
*self.as_mut().count() += 1;
Poll::Ready(Some((count, item)))
}
None => Poll::Ready(None),
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
self.stream.size_hint()
}
}
#[cfg(feature = "sink")]
impl<S, Item> Sink<Item> for Enumerate<S>
where
S: Stream + Sink<Item>,
{
type Error = S::Error;
delegate_sink!(stream, Item);
}