naga/
racy_lock.rs

1#[cfg(no_std)]
2use alloc::boxed::Box;
3#[cfg(no_std)]
4use once_cell::race::OnceBox;
5#[cfg(std)]
6use std::sync::LazyLock;
7
8#[cfg(std)]
9type Inner<T> = LazyLock<T, fn() -> T>;
10#[cfg(no_std)]
11type Inner<T> = OnceBox<T>;
12
13/// Lazy static helper that uses [`LazyLock`] with `std` and [`OnceBox`] otherwise.
14///
15/// [`LazyLock`]: https://doc.rust-lang.org/stable/std/sync/struct.LazyLock.html
16/// [`OnceBox`]: https://docs.rs/once_cell/latest/once_cell/race/struct.OnceBox.html
17pub struct RacyLock<T: 'static> {
18    inner: Inner<T>,
19    #[cfg(no_std)]
20    init: fn() -> T,
21}
22
23impl<T: 'static> RacyLock<T> {
24    #[cfg(std)]
25    /// Creates a new [`RacyLock`], which will initialize using the provided `init` function.
26    pub const fn new(init: fn() -> T) -> Self {
27        Self {
28            inner: LazyLock::new(init),
29        }
30    }
31
32    #[cfg(no_std)]
33    /// Creates a new [`RacyLock`], which will initialize using the provided `init` function.
34    pub const fn new(init: fn() -> T) -> Self {
35        Self {
36            inner: OnceBox::new(),
37            init,
38        }
39    }
40}
41
42#[cfg(std)]
43impl<T: 'static> core::ops::Deref for RacyLock<T> {
44    type Target = T;
45
46    /// Loads the internal value, initializing it if required.
47    fn deref(&self) -> &Self::Target {
48        &self.inner
49    }
50}
51
52#[cfg(no_std)]
53impl<T: 'static> core::ops::Deref for RacyLock<T> {
54    type Target = T;
55
56    /// Loads the internal value, initializing it if required.
57    fn deref(&self) -> &Self::Target {
58        self.inner.get_or_init(|| Box::new((self.init)()))
59    }
60}
naga/racy_lock.rs

naga/
racy_lock.rs
