From b5db43550185c2acd62d3f27bc89f2f24b4fbb22 Mon Sep 17 00:00:00 2001
From: datdenkikniet <jcdra1@gmail.com>
Date: Sun, 16 Mar 2025 12:46:23 +0100
Subject: rtic-sync: introduce loom compat layer and apply it to `channel`

---
 rtic-sync/src/unsafecell.rs | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 rtic-sync/src/unsafecell.rs

(limited to 'rtic-sync/src/unsafecell.rs')

diff --git a/rtic-sync/src/unsafecell.rs b/rtic-sync/src/unsafecell.rs
new file mode 100644
index 0000000..e1774f8
--- /dev/null
+++ b/rtic-sync/src/unsafecell.rs
@@ -0,0 +1,43 @@
+//! Compat layer for [`core::cell::UnsafeCell`] and `loom::cell::UnsafeCell`.
+
+#[cfg(loom)]
+pub use loom::cell::UnsafeCell;
+
+#[cfg(not(loom))]
+pub use core::UnsafeCell;
+
+#[cfg(not(loom))]
+mod core {
+    /// An [`core::cell::UnsafeCell`] wrapper that provides compatibility with
+    /// loom's UnsafeCell.
+    #[derive(Debug)]
+    pub struct UnsafeCell<T>(core::cell::UnsafeCell<T>);
+
+    impl<T> UnsafeCell<T> {
+        /// Create a new `UnsafeCell`.
+        pub const fn new(data: T) -> UnsafeCell<T> {
+            UnsafeCell(core::cell::UnsafeCell::new(data))
+        }
+
+        /// Access the contents of the `UnsafeCell` through a mut pointer.
+        pub fn get_mut(&self) -> MutPtr<T> {
+            MutPtr(self.0.get())
+        }
+
+        pub unsafe fn with_mut<F, R>(&self, f: F) -> R
+        where
+            F: FnOnce(*mut T) -> R,
+        {
+            f(self.0.get())
+        }
+    }
+
+    pub struct MutPtr<T>(*mut T);
+
+    impl<T> MutPtr<T> {
+        #[allow(clippy::mut_from_ref)]
+        pub unsafe fn deref(&self) -> &mut T {
+            &mut *self.0
+        }
+    }
+}
-- 
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