simple-rc-async 0.1.1

DryadSynth solver for string transformation programs
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

use std::{borrow::BorrowMut, cell::{Cell, RefCell}, collections::VecDeque, ops::Deref, os::unix::thread, pin::Pin, rc::{Rc, Weak}, task::{Context, LocalWaker, Poll}};

use futures_core::Future;

pub(crate) struct Channel<T: Clone> {
    result: Poll<T>,
    waker: VecDeque<LocalWaker>,
}

#[derive(Clone)]
pub struct Reciever<T: Clone>(Weak<RefCell<Channel<T>>>);

impl<T: Clone + std::fmt::Debug> futures_core::stream::Stream for Reciever<T> {
    type Item = T;

    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
        if let Some(this) = self.0.upgrade() {
            Sender(this).poll_ref(cx).map(|x| Some(x))
        } else {
            Poll::Ready(None)
        }
    }
}

#[derive(Clone)]
pub struct Sender<T: Clone>(Rc<RefCell<Channel<T>>>);

impl<T: Clone + std::fmt::Debug> std::future::Future for Sender<T> {
    type Output = T;

    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        self.poll_ref(cx)
    }
}


impl<T: Clone + std::fmt::Debug> Sender<T> {
    pub fn poll_ref(&self, cx: &mut Context<'_>) -> Poll<T> {
        assert!(self.0.as_ptr() as usize >= 0x200);
        let mut this = self.0.deref().borrow_mut();
        let result = std::mem::replace(&mut this.result, Poll::Pending);
        if result.is_pending() { this.waker.push_back(cx.local_waker().clone()); }
        result
    }
    pub fn new() -> Self {
        Self(Rc::new(RefCell::new(Channel {
            result: Poll::Pending,
            waker: VecDeque::new(),
        })))
    }
    pub fn send(&self, v: T, count: usize) {
        let pointer = self.0.clone();
        let count = std::cmp::min((*self.0).borrow_mut().waker.len(), count);
        
        for _ in 0..count {
            let r = (*self.0).borrow_mut().waker.pop_front();
            if let Some(waker) = r {
                {
                    assert!(Rc::ptr_eq(&self.0, &pointer));
                    let a = &*pointer;
                    let mut b = a.borrow_mut();
                    b.result = Poll::Ready(v.clone());
                }
                waker.wake();
            } else { break; } 
        }
    }

    pub fn reciever(&self) -> Reciever<T> {
        Reciever(Rc::downgrade(&self.0))
    }
}

pub fn channel<T: Clone + std::fmt::Debug>() -> Sender<T> {
    let a = Sender::new();
    assert!(a.0.as_ptr() as usize >= 0x200);
    a
}


#[cfg(test)]
mod test {
    use std::task::Poll;

    use futures::StreamExt;

    use crate::task;

    use super::channel;

    #[test]
    fn test() {
        let sd = channel::<usize>();
        eprintln!("Creating handle2");
        let mut rv2 = sd.reciever();
        let handle2 = task::spawn(async move {
            eprintln!("  handle2 0");
            let a = rv2.next().await.unwrap();
            eprintln!("  handle2 1");
            let b = rv2.next().await.unwrap();
            eprintln!("  handle2 2");
            let c = rv2.next().await.unwrap();
            eprintln!("  handle2 3");
            a + b + c
        });
        eprintln!("Creating handle");
        let mut rv = sd.reciever();
        let handle = task::spawn(async move {
            eprintln!("  handle 0");
            let a = rv.next().await.unwrap();
            eprintln!("  handle 1");
            let b = rv.next().await.unwrap();
            eprintln!("  handle 2");
            a + b + handle2.await
        });
        assert!(!handle.is_ready());
        eprintln!("Sending 1");
        let _ = sd.send(1, 10);
        assert!(!handle.is_ready());
        eprintln!("Sending 2");
        let _ = sd.send(2, 20);
        assert!(!handle.is_ready());
        eprintln!("Sending 3");
        let _ = sd.send(3, 30);
        assert!(handle.is_ready());
        assert!(handle.poll_rc_nocx() == Poll::Ready(9));
    }

    // #[test]
    // fn test2() {
    //     let cell1 = MaybeReady::pending();
    //     let cell2 = MaybeReady::pending();
    //     let handle1 = task::spawn(async { rv.await });
    //     let handle2 = task::spawn(async { handle1.await });
    //     assert!(!handle2.is_ready());
    //     assert!(handle2.poll_rc_nocx() == Poll::Pending);
    //     let _ = sd.send(1);
    //     assert!(handle2.is_ready());
    //     assert!(handle2.poll_rc_nocx() == Poll::Ready(1));a
    // }
}