From 1b6a04ca5504955c571d1c97504fb45ea0befee4 Mon Sep 17 00:00:00 2001
From: Valentin Popov <valentin@popov.link>
Date: Mon, 8 Jan 2024 01:21:28 +0400
Subject: Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
---
vendor/once_cell/src/imp_cs.rs | 78 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 78 insertions(+)
create mode 100644 vendor/once_cell/src/imp_cs.rs
(limited to 'vendor/once_cell/src/imp_cs.rs')
diff --git a/vendor/once_cell/src/imp_cs.rs b/vendor/once_cell/src/imp_cs.rs
new file mode 100644
index 0000000..7d05e50
--- /dev/null
+++ b/vendor/once_cell/src/imp_cs.rs
@@ -0,0 +1,78 @@
+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()
+ }
+}
--
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