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
use std::pin::Pin;
use std::task::{Context, Poll};
use futures_core::ready;
use pin_project_lite::pin_project;
use crate::actor::Actor;
use crate::fut::ActorFuture;
pin_project! {
#[project = MapProj]
#[project_replace = MapProjReplace]
#[derive(Debug)]
#[must_use = "futures do nothing unless you `.await` or poll them"]
pub enum Map<Fut, F> {
Incomplete {
#[pin]
future: Fut,
f: F,
},
Complete,
}
}
impl<Fut, F> Map<Fut, F> {
pub(super) fn new(future: Fut, f: F) -> Self {
Self::Incomplete { future, f }
}
}
impl<U, Fut, A, F> ActorFuture<A> for Map<Fut, F>
where
Fut: ActorFuture<A>,
A: Actor,
F: FnOnce(Fut::Output, &mut A, &mut A::Context) -> U,
{
type Output = U;
fn poll(
mut self: Pin<&mut Self>,
act: &mut A,
ctx: &mut A::Context,
task: &mut Context<'_>,
) -> Poll<Self::Output> {
match self.as_mut().project() {
MapProj::Incomplete { future, .. } => {
let output = ready!(future.poll(act, ctx, task));
match self.project_replace(Map::Complete) {
MapProjReplace::Incomplete { f, .. } => Poll::Ready(f(output, act, ctx)),
MapProjReplace::Complete => unreachable!(),
}
}
MapProj::Complete => {
panic!("Map must not be polled after it returned `Poll::Ready`")
}
}
}
}