diff options
author | Frank Steffahn <fdsteffahn@gmail.com> | 2020-09-12 22:58:58 +0200 |
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committer | GitHub <noreply@github.com> | 2020-09-12 22:58:58 +0200 |
commit | 8d2e3bc575f51815ae7319f1e43fe6c7d664e6e4 (patch) | |
tree | 61fa8e1da832757b996abe7b03be85f156c66d6b /tokio/src/sync | |
parent | 20ef28655354ae729a4af2098426a413e3f4d769 (diff) |
sync: add const constructors to RwLock, Notify, and Semaphore (#2833)
* Add const constructors to `RwLock`, `Notify`, and `Semaphore`.
Referring to the types in `tokio::sync`.
Also add `const` to `new` for the remaining atomic integers in `src/loom` and `UnsafeCell`.
Builds upon previous work in #2790
Closes #2756
Diffstat (limited to 'tokio/src/sync')
-rw-r--r-- | tokio/src/sync/notify.rs | 18 | ||||
-rw-r--r-- | tokio/src/sync/rwlock.rs | 21 | ||||
-rw-r--r-- | tokio/src/sync/semaphore.rs | 9 |
3 files changed, 48 insertions, 0 deletions
diff --git a/tokio/src/sync/notify.rs b/tokio/src/sync/notify.rs index 74c69e50..c69e2b07 100644 --- a/tokio/src/sync/notify.rs +++ b/tokio/src/sync/notify.rs @@ -170,6 +170,24 @@ impl Notify { } } + /// Create a new `Notify`, initialized without a permit. + /// + /// # Examples + /// + /// ``` + /// use tokio::sync::Notify; + /// + /// static NOTIFY: Notify = Notify::const_new(); + /// ``` + #[cfg(all(feature = "parking_lot", not(all(loom, test))))] + #[cfg_attr(docsrs, doc(cfg(feature = "parking_lot")))] + pub const fn const_new() -> Notify { + Notify { + state: AtomicU8::new(0), + waiters: Mutex::const_new(LinkedList::new()), + } + } + /// Wait for a notification. /// /// Equivalent to: diff --git a/tokio/src/sync/rwlock.rs b/tokio/src/sync/rwlock.rs index 650a7cf6..840889ba 100644 --- a/tokio/src/sync/rwlock.rs +++ b/tokio/src/sync/rwlock.rs @@ -485,6 +485,27 @@ impl<T: ?Sized> RwLock<T> { } } + /// Creates a new instance of an `RwLock<T>` which is unlocked. + /// + /// # Examples + /// + /// ``` + /// use tokio::sync::RwLock; + /// + /// static LOCK: RwLock<i32> = RwLock::const_new(5); + /// ``` + #[cfg(all(feature = "parking_lot", not(all(loom, test))))] + #[cfg_attr(docsrs, doc(cfg(feature = "parking_lot")))] + pub const fn const_new(value: T) -> RwLock<T> + where + T: Sized, + { + RwLock { + c: UnsafeCell::new(value), + s: Semaphore::const_new(MAX_READS), + } + } + /// Locks this rwlock with shared read access, causing the current task /// to yield until the lock has been acquired. /// diff --git a/tokio/src/sync/semaphore.rs b/tokio/src/sync/semaphore.rs index 2489d34a..136f14e6 100644 --- a/tokio/src/sync/semaphore.rs +++ b/tokio/src/sync/semaphore.rs @@ -74,6 +74,15 @@ impl Semaphore { } } + /// Creates a new semaphore with the initial number of permits. + #[cfg(all(feature = "parking_lot", not(all(loom, test))))] + #[cfg_attr(docsrs, doc(cfg(feature = "parking_lot")))] + pub const fn const_new(permits: usize) -> Self { + Self { + ll_sem: ll::Semaphore::const_new(permits), + } + } + /// Returns the current number of available permits. pub fn available_permits(&self) -> usize { self.ll_sem.available_permits() |