behavior/
deadlined.rs

1//! Pure one-shot time composition. Scheduling is a request to the emitting
2//! actor's local clock service.
3
4use tokio::time::Instant;
5
6use crate::behavior::{
7    Actions, Address, Become, Behavior, BirthMode, SendAlgebra, SendProduct, ServiceSends, User,
8    UserEvent,
9};
10use crate::supervising::{ChildEvent, ChildStopped};
11use crate::watching::{PeerEvent, PeerStopped};
12use crate::{Exit, Step};
13
14#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
15pub struct AtId(pub u64);
16
17#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
18pub struct AtGeneration(pub u64);
19
20#[derive(Debug, Clone, Copy, PartialEq, Eq)]
21pub struct ScheduleAt {
22    pub id: AtId,
23    pub generation: AtGeneration,
24    pub at: Instant,
25}
26
27#[derive(Debug, Clone, Copy, PartialEq, Eq)]
28pub struct TimeReached {
29    pub id: AtId,
30    pub generation: AtGeneration,
31    pub at: Instant,
32}
33
34#[derive(Debug, Clone, PartialEq, Eq)]
35pub enum AtEvent<E> {
36    Inner(E),
37    Reached(TimeReached),
38}
39
40pub trait TimeEvent: Sized {
41    fn time_reached(event: TimeReached) -> Option<Self>;
42}
43
44impl<E> TimeEvent for AtEvent<E> {
45    fn time_reached(event: TimeReached) -> Option<Self> {
46        Some(Self::Reached(event))
47    }
48}
49
50impl<E: UserEvent> UserEvent for AtEvent<E> {
51    type Addr = E::Addr;
52    type Message = E::Message;
53
54    fn user(from: Self::Addr, message: Self::Message) -> Self {
55        Self::Inner(E::user(from, message))
56    }
57
58    fn into_user(self) -> Result<User<Self::Addr, Self::Message>, Self> {
59        match self {
60            Self::Inner(event) => event.into_user().map_err(Self::Inner),
61            reached @ Self::Reached(_) => Err(reached),
62        }
63    }
64}
65
66impl<E: PeerEvent<A>, A: Address> PeerEvent<A> for AtEvent<E> {
67    fn peer_stopped(event: PeerStopped<A>) -> Option<Self> {
68        E::peer_stopped(event).map(Self::Inner)
69    }
70}
71
72impl<E: ChildEvent<A>, A: Address> ChildEvent<A> for AtEvent<E> {
73    fn child_stopped(event: ChildStopped<A>) -> Option<Self> {
74        E::child_stopped(event).map(Self::Inner)
75    }
76}
77
78pub type AtReaction<B> =
79    fn(&mut B) -> Result<Become<<B as Behavior>::Addr>, <B as Behavior>::Error>;
80
81pub type AtSends<B> = SendProduct<<B as Behavior>::Sends, ServiceSends<ScheduleAt>>;
82
83pub type AtActions<B> =
84    Actions<<B as Behavior>::Addr, <B as Behavior>::Ph, AtSends<B>, <B as Behavior>::Birth>;
85
86pub struct At<B: Behavior> {
87    inner: B,
88    id: AtId,
89    scheduled: Option<(AtGeneration, Instant)>,
90    on_reached: AtReaction<B>,
91}
92
93impl<B: Behavior> At<B> {
94    #[must_use]
95    pub fn new(inner: B, id: AtId, at: Option<Instant>, on_reached: AtReaction<B>) -> Self {
96        Self {
97            inner,
98            id,
99            scheduled: at.map(|at| (AtGeneration(0), at)),
100            on_reached,
101        }
102    }
103
104    #[must_use]
105    pub fn inner(&self) -> &B {
106        &self.inner
107    }
108}
109
110impl<B, A, Ph, Sends, Br> Behavior for At<B>
111where
112    A: Address + Send,
113    Sends: SendAlgebra,
114    Br: BirthMode,
115    B: Behavior<
116            Addr = A,
117            Ph = Ph,
118            Sends = Sends,
119            Birth = Br,
120            Effect = Actions<A, Ph, Sends, Br>,
121            Done = Exit<A>,
122        > + Send,
123    B::Event: TimeEvent + Send,
124    B::Msg: Send,
125{
126    type Addr = A;
127    type Msg = B::Msg;
128    type Event = AtEvent<B::Event>;
129    type Sends = SendProduct<Sends, ServiceSends<ScheduleAt>>;
130    type Ph = Ph;
131    type Error = B::Error;
132    type Birth = Br;
133    type Effect = Actions<A, Ph, Self::Sends, Br>;
134    type Done = Exit<A>;
135
136    async fn init(&mut self) -> Result<Self::Effect, B::Error> {
137        let actions = self.inner.init().await?;
138        let own = self
139            .scheduled
140            .map_or_else(ServiceSends::empty, |(generation, at)| {
141                ServiceSends::one(ScheduleAt {
142                    id: self.id,
143                    generation,
144                    at,
145                })
146            });
147        Ok(Self::wrap(actions, own))
148    }
149
150    async fn step(&mut self, event: Self::Event) -> Result<Self::Effect, B::Error> {
151        match event {
152            AtEvent::Reached(event)
153                if event.id == self.id && self.scheduled == Some((event.generation, event.at)) =>
154            {
155                self.scheduled = None;
156                let become_ = match (self.on_reached)(&mut self.inner)? {
157                    Step::Continue => Step::Continue,
158                    Step::Goto(never) => match never {},
159                    Step::Stop(exit) => Step::Stop(exit),
160                };
161                Ok(Actions {
162                    sends: SendProduct {
163                        inner: B::Sends::empty(),
164                        own: ServiceSends::empty(),
165                    },
166                    creates: Vec::new(),
167                    become_,
168                })
169            }
170            AtEvent::Reached(event) => match B::Event::time_reached(event) {
171                Some(inner) => self
172                    .inner
173                    .step(inner)
174                    .await
175                    .map(|actions| Self::wrap(actions, ServiceSends::empty())),
176                None => Ok(Actions::cont()),
177            },
178            AtEvent::Inner(event) => self
179                .inner
180                .step(event)
181                .await
182                .map(|actions| Self::wrap(actions, ServiceSends::empty())),
183        }
184    }
185}
186
187impl<B: Behavior> At<B> {
188    fn wrap(
189        actions: Actions<B::Addr, B::Ph, B::Sends, B::Birth>,
190        own: ServiceSends<ScheduleAt>,
191    ) -> AtActions<B> {
192        Actions {
193            sends: SendProduct {
194                inner: actions.sends,
195                own,
196            },
197            creates: actions.creates,
198            become_: actions.become_,
199        }
200    }
201}
behavior/deadlined.rs

behavior/
deadlined.rs
