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
|
use core::fmt;
use core::marker::PhantomData;
use core::pin::Pin;
use futures_core::future::Future;
use futures_core::ready;
use futures_core::stream::Stream;
use futures_core::task::{Context, Poll};
use futures_sink::Sink;
use pin_project_lite::pin_project;
pin_project! {
/// Sink for the [`with`](super::SinkExt::with) method.
#[must_use = "sinks do nothing unless polled"]
pub struct With<Si, Item, U, Fut, F> {
#[pin]
sink: Si,
f: F,
#[pin]
state: Option<Fut>,
_phantom: PhantomData<fn(U) -> Item>,
}
}
impl<Si, Item, U, Fut, F> fmt::Debug for With<Si, Item, U, Fut, F>
where
Si: fmt::Debug,
Fut: fmt::Debug,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("With").field("sink", &self.sink).field("state", &self.state).finish()
}
}
impl<Si, Item, U, Fut, F> With<Si, Item, U, Fut, F>
where
Si: Sink<Item>,
F: FnMut(U) -> Fut,
Fut: Future,
{
pub(super) fn new<E>(sink: Si, f: F) -> Self
where
Fut: Future<Output = Result<Item, E>>,
E: From<Si::Error>,
{
Self { state: None, sink, f, _phantom: PhantomData }
}
}
impl<Si, Item, U, Fut, F> Clone for With<Si, Item, U, Fut, F>
where
Si: Clone,
F: Clone,
Fut: Clone,
{
fn clone(&self) -> Self {
Self {
state: self.state.clone(),
sink: self.sink.clone(),
f: self.f.clone(),
_phantom: PhantomData,
}
}
}
// Forwarding impl of Stream from the underlying sink
impl<S, Item, U, Fut, F> Stream for With<S, Item, U, Fut, F>
where
S: Stream + Sink<Item>,
F: FnMut(U) -> Fut,
Fut: Future,
{
type Item = S::Item;
delegate_stream!(sink);
}
impl<Si, Item, U, Fut, F, E> With<Si, Item, U, Fut, F>
where
Si: Sink<Item>,
F: FnMut(U) -> Fut,
Fut: Future<Output = Result<Item, E>>,
E: From<Si::Error>,
{
delegate_access_inner!(sink, Si, ());
/// Completes the processing of previous item if any.
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), E>> {
let mut this = self.project();
let item = match this.state.as_mut().as_pin_mut() {
None => return Poll::Ready(Ok(())),
Some(fut) => ready!(fut.poll(cx))?,
};
this.state.set(None);
this.sink.start_send(item)?;
Poll::Ready(Ok(()))
}
}
impl<Si, Item, U, Fut, F, E> Sink<U> for With<Si, Item, U, Fut, F>
where
Si: Sink<Item>,
F: FnMut(U) -> Fut,
Fut: Future<Output = Result<Item, E>>,
E: From<Si::Error>,
{
type Error = E;
fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
ready!(self.as_mut().poll(cx))?;
ready!(self.project().sink.poll_ready(cx)?);
Poll::Ready(Ok(()))
}
fn start_send(self: Pin<&mut Self>, item: U) -> Result<(), Self::Error> {
let mut this = self.project();
assert!(this.state.is_none());
this.state.set(Some((this.f)(item)));
Ok(())
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
ready!(self.as_mut().poll(cx))?;
ready!(self.project().sink.poll_flush(cx)?);
Poll::Ready(Ok(()))
}
fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
ready!(self.as_mut().poll(cx))?;
ready!(self.project().sink.poll_close(cx)?);
Poll::Ready(Ok(()))
}
}
|
