1#[cfg(not(feature = "tokio"))]
2pub(crate) use async_lock::{Mutex, RwLock, RwLockReadGuard, RwLockWriteGuard};
3#[cfg(feature = "tokio")]
4pub(crate) use tokio::sync::{Mutex, RwLock, RwLockReadGuard, RwLockWriteGuard};
5
6/// An abstraction over async semaphore API.
7#[cfg(not(feature = "tokio"))]
8pub(crate) struct Semaphore(async_lock::Semaphore);
9#[cfg(feature = "tokio")]
10pub(crate) struct Semaphore(tokio::sync::Semaphore);
11
12impl Semaphore {
13 pub const fn new(permits: usize) -> Self {
14 #[cfg(not(feature = "tokio"))]
15 let semaphore: Semaphore = async_lock::Semaphore::new(permits);
16 #[cfg(feature = "tokio")]
17 let semaphore = tokio::sync::Semaphore::const_new(permits);
18
19 Self(semaphore)
20 }
21
22 pub async fn acquire(&self) -> SemaphorePermit<'_> {
23 #[cfg(not(feature = "tokio"))]
24 {
25 self.0.acquire().await
26 }
27 #[cfg(feature = "tokio")]
28 {
29 // SAFETY: Since we never explicitly close the sempaphore, `acquire` can't fail.
30 self.0.acquire().await.unwrap()
31 }
32 }
33}
34
35#[cfg(not(feature = "tokio"))]
36pub(crate) type SemaphorePermit<'a> = async_lock::SemaphoreGuard<'a>;
37#[cfg(feature = "tokio")]
38pub(crate) type SemaphorePermit<'a> = tokio::sync::SemaphorePermit<'a>;
39