| // SPDX-License-Identifier: Apache-2.0 OR MIT |
| |
| //! The contents of this file come from the Rust standard library, hosted in |
| //! the <https://github.com/rust-lang/rust> repository, licensed under |
| //! "Apache-2.0 OR MIT" and adapted for kernel use. For copyright details, |
| //! see <https://github.com/rust-lang/rust/blob/master/COPYRIGHT>. |
| |
| use crate::sync::{arc::ArcInner, Arc}; |
| use core::any::Any; |
| |
| impl Arc<dyn Any + Send + Sync> { |
| /// Attempt to downcast the `Arc<dyn Any + Send + Sync>` to a concrete type. |
| pub fn downcast<T>(self) -> core::result::Result<Arc<T>, Self> |
| where |
| T: Any + Send + Sync, |
| { |
| if (*self).is::<T>() { |
| // SAFETY: We have just checked that the type is correct, so we can cast the pointer. |
| unsafe { |
| let ptr = self.ptr.cast::<ArcInner<T>>(); |
| core::mem::forget(self); |
| Ok(Arc::from_inner(ptr)) |
| } |
| } else { |
| Err(self) |
| } |
| } |
| } |