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Diffstat (limited to 'vendor/once_cell/src/imp_cs.rs')
-rw-r--r-- | vendor/once_cell/src/imp_cs.rs | 78 |
1 files changed, 0 insertions, 78 deletions
diff --git a/vendor/once_cell/src/imp_cs.rs b/vendor/once_cell/src/imp_cs.rs deleted file mode 100644 index 7d05e50..0000000 --- a/vendor/once_cell/src/imp_cs.rs +++ /dev/null @@ -1,78 +0,0 @@ -use core::panic::{RefUnwindSafe, UnwindSafe}; - -use portable_atomic::{AtomicBool, Ordering}; -use critical_section::{CriticalSection, Mutex}; - -use crate::unsync; - -pub(crate) struct OnceCell<T> { - initialized: AtomicBool, - // Use `unsync::OnceCell` internally since `Mutex` does not provide - // interior mutability and to be able to re-use `get_or_try_init`. - value: Mutex<unsync::OnceCell<T>>, -} - -// Why do we need `T: Send`? -// Thread A creates a `OnceCell` and shares it with -// scoped thread B, which fills the cell, which is -// then destroyed by A. That is, destructor observes -// a sent value. -unsafe impl<T: Sync + Send> Sync for OnceCell<T> {} -unsafe impl<T: Send> Send for OnceCell<T> {} - -impl<T: RefUnwindSafe + UnwindSafe> RefUnwindSafe for OnceCell<T> {} -impl<T: UnwindSafe> UnwindSafe for OnceCell<T> {} - -impl<T> OnceCell<T> { - pub(crate) const fn new() -> OnceCell<T> { - OnceCell { initialized: AtomicBool::new(false), value: Mutex::new(unsync::OnceCell::new()) } - } - - pub(crate) const fn with_value(value: T) -> OnceCell<T> { - OnceCell { - initialized: AtomicBool::new(true), - value: Mutex::new(unsync::OnceCell::with_value(value)), - } - } - - #[inline] - pub(crate) fn is_initialized(&self) -> bool { - self.initialized.load(Ordering::Acquire) - } - - #[cold] - pub(crate) fn initialize<F, E>(&self, f: F) -> Result<(), E> - where - F: FnOnce() -> Result<T, E>, - { - critical_section::with(|cs| { - let cell = self.value.borrow(cs); - cell.get_or_try_init(f).map(|_| { - self.initialized.store(true, Ordering::Release); - }) - }) - } - - /// Get the reference to the underlying value, without checking if the cell - /// is initialized. - /// - /// # Safety - /// - /// Caller must ensure that the cell is in initialized state, and that - /// the contents are acquired by (synchronized to) this thread. - pub(crate) unsafe fn get_unchecked(&self) -> &T { - debug_assert!(self.is_initialized()); - // SAFETY: The caller ensures that the value is initialized and access synchronized. - self.value.borrow(CriticalSection::new()).get().unwrap_unchecked() - } - - #[inline] - pub(crate) fn get_mut(&mut self) -> Option<&mut T> { - self.value.get_mut().get_mut() - } - - #[inline] - pub(crate) fn into_inner(self) -> Option<T> { - self.value.into_inner().into_inner() - } -} |