rx_rust/operators/conditional_boolean/
skip_until.rs

1use crate::safe_lock_option_observer;
2use crate::utils::types::{Mutable, NecessarySend, Shared};
3use crate::utils::unsub_after_termination::subscribe_unsub_after_termination;
4use crate::{
5    disposable::subscription::Subscription,
6    observable::Observable,
7    observer::{Observer, Termination},
8    utils::types::MarkerType,
9};
10use educe::Educe;
11use std::marker::PhantomData;
12use std::sync::atomic::{AtomicBool, Ordering};
13
14/// Discards items emitted by a source Observable until a second Observable emits an item.
15/// See <https://reactivex.io/documentation/operators/skipuntil.html>
16///
17/// # Examples
18/// ```rust
19/// use rx_rust::{
20///     observable::observable_ext::ObservableExt,
21///     observer::{Observer, Termination},
22///     operators::conditional_boolean::skip_until::SkipUntil,
23///     subject::publish_subject::PublishSubject,
24/// };
25/// use std::{convert::Infallible, sync::{Arc, Mutex}};
26///
27/// let values = Arc::new(Mutex::new(Vec::new()));
28/// let terminations = Arc::new(Mutex::new(Vec::new()));
29///
30/// let mut source: PublishSubject<'_, i32, Infallible> = PublishSubject::default();
31/// let mut gate: PublishSubject<'_, (), Infallible> = PublishSubject::default();
32/// let values_observer = Arc::clone(&values);
33/// let terminations_observer = Arc::clone(&terminations);
34///
35/// let subscription = SkipUntil::new(source.clone(), gate.clone()).subscribe_with_callback(
36///     move |value| values_observer.lock().unwrap().push(value),
37///     move |termination| terminations_observer
38///         .lock()
39///         .unwrap()
40///         .push(termination),
41/// );
42///
43/// source.on_next(1);
44/// gate.on_next(());
45/// source.on_next(2);
46/// source.on_termination(Termination::Completed);
47/// drop(subscription);
48///
49/// assert_eq!(&*values.lock().unwrap(), &[2]);
50/// assert_eq!(
51///     &*terminations.lock().unwrap(),
52///     &[Termination::Completed]
53/// );
54/// ```
55#[derive(Educe)]
56#[educe(Debug, Clone)]
57pub struct SkipUntil<OE, OE1> {
58    source: OE,
59    start: OE1,
60}
61
62impl<OE, OE1> SkipUntil<OE, OE1> {
63    pub fn new<'or, 'sub, T, E>(source: OE, start: OE1) -> Self
64    where
65        OE: Observable<'or, 'sub, T, E>,
66        OE1: Observable<'or, 'sub, (), E>,
67    {
68        Self { source, start }
69    }
70}
71
72impl<'or, 'sub, T, E, OE, OE1> Observable<'or, 'sub, T, E> for SkipUntil<OE, OE1>
73where
74    T: 'or,
75    OE: Observable<'or, 'sub, T, E>,
76    OE1: Observable<'or, 'sub, (), E>,
77    'sub: 'or,
78{
79    fn subscribe(self, observer: impl Observer<T, E> + NecessarySend + 'or) -> Subscription<'sub> {
80        subscribe_unsub_after_termination(observer, |observer| {
81            let observer = Shared::new(Mutable::new(Some(observer)));
82            let started = Shared::new(AtomicBool::new(false));
83            let start_observer = StartObserver {
84                observer: observer.clone(),
85                started: started.clone(),
86                _marker: PhantomData,
87            };
88            let subscription_1 = self.start.subscribe(start_observer);
89            let observer = SkipUntilObserver { observer, started };
90            let subscription_2 = self.source.subscribe(observer);
91            subscription_1 + subscription_2
92        })
93    }
94}
95
96struct SkipUntilObserver<OR> {
97    observer: Shared<Mutable<Option<OR>>>,
98    started: Shared<AtomicBool>,
99}
100
101impl<T, E, OR> Observer<T, E> for SkipUntilObserver<OR>
102where
103    OR: Observer<T, E>,
104{
105    fn on_next(&mut self, value: T) {
106        if self.started.load(Ordering::SeqCst) {
107            safe_lock_option_observer!(on_next: self.observer, value);
108        }
109    }
110
111    fn on_termination(self, termination: Termination<E>) {
112        safe_lock_option_observer!(on_termination: self.observer, termination);
113    }
114}
115
116struct StartObserver<T, OR> {
117    observer: Shared<Mutable<Option<OR>>>,
118    started: Shared<AtomicBool>,
119    _marker: MarkerType<T>,
120}
121
122impl<T, E, OR> Observer<(), E> for StartObserver<T, OR>
123where
124    OR: Observer<T, E>,
125{
126    fn on_next(&mut self, _: ()) {
127        self.started.store(true, Ordering::SeqCst);
128    }
129
130    fn on_termination(self, termination: Termination<E>) {
131        match termination {
132            Termination::Completed => {}
133            Termination::Error(_) => {
134                safe_lock_option_observer!(on_termination: self.observer, termination);
135            }
136        }
137    }
138}
rx_rust/operators/conditional_boolean/skip_until.rs

rx_rust/operators/conditional_boolean/
skip_until.rs
