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