rx_rust/operators/others/
map_infallible_to_error.rs

1use crate::utils::types::NecessarySend;
2use crate::{
3    disposable::subscription::Subscription,
4    observable::Observable,
5    observer::{Observer, Termination},
6    utils::types::MarkerType,
7};
8use educe::Educe;
9use std::{convert::Infallible, marker::PhantomData};
10
11/// Maps an Observable with an `Infallible` error type to an Observable with a concrete error type.
12///
13/// # Examples
14/// ```rust
15/// use rx_rust::{
16///     observable::observable_ext::ObservableExt,
17///     observer::Termination,
18///     operators::{
19///         creating::from_iter::FromIter,
20///         others::map_infallible_to_error::MapInfallibleToError,
21///     },
22/// };
23///
24/// let mut values = Vec::new();
25/// let mut terminations = Vec::new();
26///
27/// MapInfallibleToError::<String, _>::new(FromIter::new(vec![1, 2]))
28///     .subscribe_with_callback(
29///         |value| values.push(value),
30///         |termination| terminations.push(termination),
31///     );
32///
33/// assert_eq!(values, vec![1, 2]);
34/// assert_eq!(terminations, vec![Termination::Completed]);
35/// ```
36#[derive(Educe)]
37#[educe(Debug, Clone)]
38pub struct MapInfallibleToError<E, OE> {
39    source: OE,
40    _marker: MarkerType<E>,
41}
42
43impl<E, OE> MapInfallibleToError<E, OE> {
44    pub fn new(source: OE) -> Self {
45        Self {
46            source,
47            _marker: PhantomData,
48        }
49    }
50}
51
52impl<'or, 'sub, T, E, OE> Observable<'or, 'sub, T, E> for MapInfallibleToError<E, OE>
53where
54    E: 'or,
55    OE: Observable<'or, 'sub, T, Infallible>,
56{
57    fn subscribe(self, observer: impl Observer<T, E> + NecessarySend + 'or) -> Subscription<'sub> {
58        let observer = MapInfallibleToErrorObserver {
59            observer,
60            _marker: PhantomData,
61        };
62        self.source.subscribe(observer)
63    }
64}
65
66struct MapInfallibleToErrorObserver<E, OR> {
67    observer: OR,
68    _marker: MarkerType<E>,
69}
70
71impl<T, E, OR> Observer<T, Infallible> for MapInfallibleToErrorObserver<E, OR>
72where
73    OR: Observer<T, E>,
74{
75    fn on_next(&mut self, value: T) {
76        self.observer.on_next(value);
77    }
78
79    fn on_termination(self, termination: Termination<Infallible>) {
80        match termination {
81            Termination::Completed => self.observer.on_termination(Termination::Completed),
82            Termination::Error(_) => unreachable!(),
83        }
84    }
85}
rx_rust/operators/others/map_infallible_to_error.rs

rx_rust/operators/others/
map_infallible_to_error.rs
