actix/fut/try_future/
and_then.rs

1use std::{
2    pin::Pin,
3    task::{Context, Poll},
4};
5
6use futures_util::ready;
7use pin_project_lite::pin_project;
8
9use crate::{
10    actor::Actor,
11    fut::{future::ActorFuture, try_future::ActorTryFuture},
12};
13
14pin_project! {
15    /// Future for the `and_then` combinator, chaining computations
16    /// on the end of another actor future regardless of its outcome.
17    ///
18    /// This is created by the `ActorTryFuture::and_then` method.
19    #[project = AndThenProj]
20    #[derive(Debug)]
21    #[must_use = "futures do nothing unless polled"]
22    pub enum AndThen<A, B, F> {
23        First {
24            #[pin]
25            fut1: A,
26            data: Option<F>,
27        },
28        Second {
29            #[pin]
30            fut2: B
31        },
32        Empty,
33    }
34}
35
36pub(super) fn new<A, B, F, Act>(future: A, f: F) -> AndThen<A, B, F>
37where
38    A: ActorTryFuture<Act>,
39    B: ActorTryFuture<Act>,
40    Act: Actor,
41{
42    AndThen::First {
43        fut1: future,
44        data: Some(f),
45    }
46}
47
48impl<A, B, F, Act> ActorFuture<Act> for AndThen<A, B, F>
49where
50    A: ActorTryFuture<Act>,
51    B: ActorTryFuture<Act, Error = A::Error>,
52    F: FnOnce(A::Ok, &mut Act, &mut Act::Context) -> B,
53    Act: Actor,
54{
55    type Output = Result<B::Ok, A::Error>;
56
57    fn poll(
58        mut self: Pin<&mut Self>,
59        act: &mut Act,
60        ctx: &mut Act::Context,
61        task: &mut Context<'_>,
62    ) -> Poll<Self::Output> {
63        match self.as_mut().project() {
64            AndThenProj::First { fut1, data } => {
65                let ok = ready!(fut1.try_poll(act, ctx, task))?;
66                let data = data.take().unwrap();
67                let fut2 = data(ok, act, ctx);
68                self.set(AndThen::Second { fut2 });
69                self.poll(act, ctx, task)
70            }
71            AndThenProj::Second { fut2 } => {
72                let res = ready!(fut2.try_poll(act, ctx, task));
73                self.set(AndThen::Empty);
74                Poll::Ready(res)
75            }
76            AndThenProj::Empty => panic!("ActorFuture polled after finish"),
77        }
78    }
79}
actix/fut/try_future/and_then.rs

actix/fut/try_future/
and_then.rs
