1#![allow(missing_docs)]
2
3use finchers_core::endpoint::{Context, Endpoint, IntoEndpoint};
4use finchers_core::task::{self, Task};
5use finchers_core::{Error, PollResult};
6
7pub fn new<E, F, T>(endpoint: E, f: F) -> Map<E::Endpoint, F>
8where
9 E: IntoEndpoint,
10 F: FnOnce(E::Output) -> T + Clone + Send + Sync,
11{
12 Map {
13 endpoint: endpoint.into_endpoint(),
14 f,
15 }
16}
17
18#[derive(Copy, Clone, Debug)]
19pub struct Map<E, F> {
20 endpoint: E,
21 f: F,
22}
23
24impl<E, F, T> Endpoint for Map<E, F>
25where
26 E: Endpoint,
27 F: FnOnce(E::Output) -> T + Clone + Send + Sync,
28{
29 type Output = F::Output;
30 type Task = MapTask<E::Task, F>;
31
32 fn apply(&self, cx: &mut Context) -> Option<Self::Task> {
33 Some(MapTask {
34 task: self.endpoint.apply(cx)?,
35 f: Some(self.f.clone()),
36 })
37 }
38}
39
40#[derive(Debug)]
41pub struct MapTask<T, F> {
42 task: T,
43 f: Option<F>,
44}
45
46impl<T, F, U> Task for MapTask<T, F>
47where
48 T: Task + Send,
49 F: FnOnce(T::Output) -> U + Send,
50{
51 type Output = U;
52
53 fn poll_task(&mut self, cx: &mut task::Context) -> PollResult<Self::Output, Error> {
54 self.task.poll_task(cx).map_ok(|item| {
55 let f = self.f.take().expect("cannot resolve twice");
56 cx.input().enter_scope(|| f(item))
57 })
58 }
59}