dfir_rs/scheduled/handoff/
tee.rs

1//! Module for teeing handoffs, not currently used much.
2
3use std::cell::RefCell;
4use std::collections::VecDeque;
5use std::rc::Rc;
6
7use super::{CanReceive, Handoff, HandoffMeta};
8
9struct ReaderHandoff<T> {
10    contents: VecDeque<Vec<T>>,
11}
12
13impl<T> Default for ReaderHandoff<T> {
14    fn default() -> Self {
15        Self {
16            contents: Default::default(),
17        }
18    }
19}
20
21struct TeeingHandoffInternal<T> {
22    /// (is alive, reader)
23    readers: Vec<(bool, ReaderHandoff<T>)>,
24}
25
26/// A [Handoff] which is part of a "family" of handoffs. Writing to this handoff
27/// will write to every reader. New readers can be created by calling `tee`.
28#[derive(Clone)]
29pub struct TeeingHandoff<T>
30where
31    T: 'static,
32{
33    read_from: usize,
34    internal: Rc<RefCell<TeeingHandoffInternal<T>>>,
35}
36
37impl<T> Default for TeeingHandoff<T> {
38    fn default() -> Self {
39        TeeingHandoff {
40            read_from: 0,
41            internal: Rc::new(RefCell::new(TeeingHandoffInternal {
42                readers: vec![(true, ReaderHandoff::<T>::default())],
43            })),
44        }
45    }
46}
47
48impl<T> TeeingHandoff<T>
49where
50    T: Clone,
51{
52    /// Tee the internal shared datastructure to create a new tee output.
53    #[must_use]
54    pub(crate) fn tee(&self) -> Self {
55        let id = (*self.internal).borrow().readers.len();
56        (*self.internal)
57            .borrow_mut()
58            .readers
59            .push((true, ReaderHandoff::default()));
60        Self {
61            read_from: id,
62            internal: self.internal.clone(),
63        }
64    }
65
66    /// Mark this particular teeing handoff output as dead, so no more data will be written to it.
67    pub(crate) fn drop(&self) {
68        self.internal.borrow_mut().readers[self.read_from].0 = false;
69    }
70}
71
72impl<T> HandoffMeta for TeeingHandoff<T> {
73    /// If this output's buffer is empty, return true.
74    fn is_bottom(&self) -> bool {
75        self.internal.borrow().readers[self.read_from]
76            .1
77            .contents
78            .iter()
79            .all(Vec::is_empty)
80    }
81}
82
83impl<T> Handoff for TeeingHandoff<T> {
84    type Inner = VecDeque<Vec<T>>;
85
86    fn take_inner(&self) -> Self::Inner {
87        std::mem::take(
88            &mut (*self.internal).borrow_mut().readers[self.read_from]
89                .1
90                .contents,
91        )
92    }
93
94    fn borrow_mut_swap(&self) -> std::cell::RefMut<'_, Self::Inner> {
95        todo!()
96    }
97}
98
99impl<T> CanReceive<Vec<T>> for TeeingHandoff<T>
100where
101    T: Clone,
102{
103    fn give(&self, vec: Vec<T>) -> Vec<T> {
104        let readers = &mut (*self.internal).borrow_mut().readers;
105        if let Some((last, rest)) = readers.split_last_mut() {
106            for reader in rest {
107                if reader.0 {
108                    reader.1.contents.push_back(vec.clone());
109                }
110            }
111            if last.0 {
112                last.1.contents.push_back(vec);
113            }
114        }
115        Vec::new()
116    }
117}
dfir_rs/scheduled/handoff/tee.rs

dfir_rs/scheduled/handoff/
tee.rs
