Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/third_party/rust/fallible_collections/src/arc.rs b/third_party/rust/fallible_collections/src/arc.rs
new file mode 100644
index 0000000000..282b8e5555
--- /dev/null
+++ b/third_party/rust/fallible_collections/src/arc.rs
@@ -0,0 +1,52 @@
+//! Implement a Fallible Arc
+use super::FallibleBox;
+use super::TryClone;
+
+use crate::TryReserveError;
+use alloc::boxed::Box;
+use alloc::sync::Arc;
+
+/// trait to implement Fallible Arc
+#[deprecated(
+	since = "0.3.1",
+	note = "⚠️️️this function is not completely fallible, it can panic !, see [issue](https://github.com/vcombey/fallible_collections/issues/13). help wanted"
+)]
+pub trait FallibleArc<T> {
+    /// try creating a new Arc, returning a Result<Box<T>,
+    /// TryReserveError> if allocation failed
+    fn try_new(t: T) -> Result<Self, TryReserveError>
+    where
+        Self: Sized;
+}
+
+#[allow(deprecated)]
+impl<T> FallibleArc<T> for Arc<T> {
+    fn try_new(t: T) -> Result<Self, TryReserveError> {
+        // doesn't work as the inner variable of arc are also stocked in the box
+
+        let b = <Box<T> as FallibleBox<T>>::try_new(t)?;
+        Ok(Arc::from(b))
+    }
+}
+
+/// Just a TryClone boilerplate for Arc
+impl<T: ?Sized> TryClone for Arc<T> {
+    fn try_clone(&self) -> Result<Self, TryReserveError> {
+        Ok(self.clone())
+    }
+}
+
+#[cfg(test)]
+mod test {
+    #[test]
+    fn fallible_rc() {
+        use std::sync::Arc;
+
+        let mut x = Arc::new(3);
+        *Arc::get_mut(&mut x).unwrap() = 4;
+        assert_eq!(*x, 4);
+
+        let _y = Arc::clone(&x);
+        assert!(Arc::get_mut(&mut x).is_none());
+    }
+}