vuo 0.1.1

An asynchronous stream processing library for Rust, built on Actix, providing a rich set of functional operators.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172

use crate::stream::{Stream, StreamMessage, Streamable};
use actix::prelude::*;
use futures::FutureExt;
use std::fmt; // Added for fmt::Debug
use std::marker::PhantomData;
use std::sync::{Arc, Mutex};

// Internal messages for SignalActor
struct GetValue<A>(PhantomData<A>)
where
    A: 'static + Send + Clone + Unpin + fmt::Debug;

impl<A> Message for GetValue<A>
where
    A: 'static + Send + Clone + Unpin + fmt::Debug,
{
    type Result = Option<A>;
}

struct SetValue<A>(A)
where
    A: 'static + Send + Clone + Unpin + fmt::Debug;

impl<A> Message for SetValue<A>
where
    A: 'static + Send + Clone + Unpin + fmt::Debug,
{
    type Result = ();
}

struct SubscribeDiscrete<A>
where
    A: 'static + Send + Clone + Unpin + fmt::Debug,
{
    recipient: Recipient<StreamMessage<A>>,
}

impl<A> Message for SubscribeDiscrete<A>
where
    A: 'static + Send + Clone + Unpin + fmt::Debug,
{
    type Result = ();
}

// SignalActor: Holds the current value and manages discrete updates to subscribers.
struct SignalActor<A>
where
    A: 'static + Send + Clone + Unpin + fmt::Debug,
{
    current_value: Arc<Mutex<Option<A>>>,
    subscribers: Vec<Recipient<StreamMessage<A>>>,
}

impl<A> SignalActor<A>
where
    A: 'static + Send + Clone + Unpin + fmt::Debug,
{
    fn new(initial_value: Option<A>) -> Self {
        SignalActor {
            current_value: Arc::new(Mutex::new(initial_value)),
            subscribers: Vec::new(),
        }
    }
}

impl<A> Actor for SignalActor<A>
where
    A: 'static + Send + Clone + Unpin + fmt::Debug,
{
    type Context = Context<Self>;
}

impl<A> Handler<GetValue<A>> for SignalActor<A>
where
    A: 'static + Send + Clone + Unpin + fmt::Debug,
{
    type Result = Option<A>;

    fn handle(&mut self, _msg: GetValue<A>, _ctx: &mut Context<Self>) -> Self::Result {
        self.current_value.lock().unwrap().clone()
    }
}

impl<A> Handler<SetValue<A>> for SignalActor<A>
where
    A: 'static + Send + Clone + Unpin + fmt::Debug,
{
    type Result = ();

    fn handle(&mut self, msg: SetValue<A>, _ctx: &mut Context<Self>) -> Self::Result {
        let mut value_guard = self.current_value.lock().unwrap();
        *value_guard = Some(msg.0.clone());

        // Notify subscribers
        self.subscribers
            .retain(|sub| sub.try_send(StreamMessage::Element(msg.0.clone())).is_ok());
    }
}

impl<A> Handler<SubscribeDiscrete<A>> for SignalActor<A>
where
    A: 'static + Send + Clone + Unpin + fmt::Debug,
{
    type Result = ();

    fn handle(&mut self, msg: SubscribeDiscrete<A>, _ctx: &mut Context<Self>) -> Self::Result {
        // Send current value immediately if available
        if let Some(val) = self.current_value.lock().unwrap().as_ref() {
            let _ = msg.recipient.try_send(StreamMessage::Element(val.clone()));
        }
        self.subscribers.push(msg.recipient);
    }
}

// Public Signal struct
#[derive(Clone)]
pub struct Signal<A>
where
    A: 'static + Send + Clone + Unpin + fmt::Debug,
{
    actor_addr: Addr<SignalActor<A>>,
}

impl<A> Signal<A>
where
    A: 'static + Send + Clone + Unpin + fmt::Debug + Streamable, // Streamable for discrete()
{
    pub fn new(initial_value: A) -> Self {
        Signal {
            actor_addr: SignalActor::new(Some(initial_value)).start(),
        }
    }

    pub fn constant(value: A) -> Self {
        Signal::new(value)
    }

    pub fn empty() -> Self {
        Signal {
            actor_addr: SignalActor::new(None).start(),
        }
    }

    pub async fn get_value(&self) -> Option<A> {
        self.actor_addr
            .send(GetValue(PhantomData))
            .await
            .unwrap_or(None)
    }

    pub fn set_value(&self, value: A) {
        self.actor_addr.do_send(SetValue(value));
    }

    // Returns a stream that emits the current value and then all subsequent changes.
    pub fn discrete(&self) -> Stream<A> {
        let actor_addr_clone = self.actor_addr.clone();
        let setup_fn = Box::new(move |downstream_recipient: Recipient<StreamMessage<A>>| {
            async move {
                actor_addr_clone.do_send(SubscribeDiscrete {
                    recipient: downstream_recipient,
                });
                Ok(())
            }
            .boxed() // Ensure .boxed() is available via futures::FutureExt
        });
        Stream {
            setup_fn,
            _phantom: PhantomData,
        }
    }
}