tracexec_core/primitives/
local_chan.rs

1//! Simple implementation of a `!Send` & `!Sync` channel.
2//!
3//! It is useful for single threaded scenarios.
4//!
5//! Specifically, in tracexec it is used to implement the event-action pattern:
6//! https://ratatui.rs/concepts/event-handling/#centralized-catching-message-passing
7
8use std::{
9  cell::RefCell,
10  collections::VecDeque,
11  rc::Rc,
12};
13
14pub fn unbounded<T>() -> (LocalUnboundedSender<T>, LocalUnboundedReceiver<T>) {
15  let inner = Rc::new(RefCell::new(VecDeque::new()));
16  (
17    LocalUnboundedSender {
18      inner: inner.clone(),
19    },
20    LocalUnboundedReceiver { inner },
21  )
22}
23
24#[derive(Debug, Clone)]
25pub struct LocalUnboundedSender<T> {
26  inner: Rc<RefCell<VecDeque<T>>>,
27}
28
29#[derive(Debug, Clone)]
30pub struct LocalUnboundedReceiver<T> {
31  inner: Rc<RefCell<VecDeque<T>>>,
32}
33
34impl<T> LocalUnboundedSender<T> {
35  pub fn send(&self, v: T) {
36    self.inner.borrow_mut().push_back(v);
37  }
38}
39impl<T> LocalUnboundedReceiver<T> {
40  pub fn receive(&self) -> Option<T> {
41    self.inner.borrow_mut().pop_front()
42  }
43}
44
45#[cfg(test)]
46mod tests {
47  use test_that::prelude::*;
48
49  use super::*;
50
51  #[test]
52  fn test_basic_send_receive() {
53    let (sender, receiver) = unbounded();
54
55    sender.send(42);
56    sender.send(100);
57
58    assert_that!(receiver.receive(), some(eq(42)));
59    assert_that!(receiver.receive(), some(eq(100)));
60    // Queue is now empty
61    assert_that!(receiver.receive(), none());
62  }
63
64  #[test]
65  fn test_receive_empty_channel() {
66    let (_sender, receiver): (LocalUnboundedSender<i32>, _) = unbounded();
67    assert_that!(receiver.receive(), none());
68  }
69
70  #[test]
71  fn test_multiple_senders_receive() {
72    let (sender1, receiver1) = unbounded();
73    let sender2 = sender1.clone();
74    let receiver2 = receiver1.clone();
75
76    sender1.send(1);
77    sender2.send(2);
78
79    // Order is preserved
80    assert_that!(receiver1.receive(), some(eq(1)));
81    assert_that!(receiver2.receive(), some(eq(2)));
82
83    // Channel empty now
84    assert_that!(receiver1.receive(), none());
85    assert_that!(receiver2.receive(), none());
86  }
87
88  #[test]
89  fn test_fifo_order_with_multiple_elements() {
90    let (sender, receiver) = unbounded();
91
92    for i in 0..10 {
93      sender.send(i);
94    }
95
96    for i in 0..10 {
97      assert_that!(receiver.receive(), some(eq(i)));
98    }
99
100    assert_that!(receiver.receive(), none());
101  }
102
103  #[test]
104  fn test_clone_sender_receiver_shares_queue() {
105    let (sender, receiver) = unbounded();
106    let sender2 = sender.clone();
107    let receiver2 = receiver.clone();
108
109    sender.send(1);
110    sender2.send(2);
111
112    assert_that!(receiver2.receive(), some(eq(1)));
113    assert_that!(receiver.receive(), some(eq(2)));
114    assert_that!(receiver2.receive(), none());
115  }
116}
tracexec_core/primitives/local_chan.rs

tracexec_core/primitives/
local_chan.rs
