veneer 0.2.3

A very thin std-like library that doesn't depend on libc
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

use core::{
    cell::UnsafeCell,
    ops::{Deref, DerefMut},
    sync::atomic::{
        AtomicBool,
        Ordering::{Acquire, Release},
    },
};

pub struct SpinLock<T> {
    locked: AtomicBool,
    contents: UnsafeCell<T>,
}

unsafe impl<T> Sync for SpinLock<T> {}

pub struct SpinLockGuard<'a, T> {
    lock: &'a SpinLock<T>,
}

impl<T> SpinLock<T> {
    pub const fn new(inner: T) -> Self {
        Self {
            locked: AtomicBool::new(false),
            contents: UnsafeCell::new(inner),
        }
    }

    pub fn lock(&self) -> SpinLockGuard<T> {
        while self
            .locked
            .compare_exchange(false, true, Acquire, Acquire)
            .is_err()
        {
            core::hint::spin_loop();
        }
        SpinLockGuard { lock: self }
    }
}

impl<T> Drop for SpinLockGuard<'_, T> {
    fn drop(&mut self) {
        self.lock.locked.store(false, Release);
    }
}

impl<T> Deref for SpinLockGuard<'_, T> {
    type Target = T;

    fn deref(&self) -> &T {
        unsafe { &*self.lock.contents.get() }
    }
}

impl<T> DerefMut for SpinLockGuard<'_, T> {
    fn deref_mut(&mut self) -> &mut T {
        unsafe { &mut *self.lock.contents.get() }
    }
}