5 releases
0.1.4 | May 11, 2023 |
---|---|
0.1.3 | May 11, 2023 |
0.1.2 | May 11, 2023 |
0.1.1 | May 11, 2023 |
0.1.0 | May 11, 2023 |
#2153 in Data structures
Used in 2 crates
9KB
92 lines
any_handle
any_handle
provides a reference-counting smart pointer type, AnyHandle<T>
,
which can store a value of a type T
. The special AnyHandle<dyn Any>
allows for
downcasting to any other AnyHandle<T: Any>
type.
Internally, an AnyHandle
is an Arc<RwLock<Box<dyn Any>>>
, and matches the
reference-counting behaviour of Arc
as well as the many-readers-or-one-writer
thread safety model of RwLock
.
use any_handle::{AnyHandle, Any};
struct SomeStruct (i32);
fn main() -> Option<()>{
// Initialize a handle with an unknown type.
// If you want to pass in a Box<dyn SomeOtherTrait>, instead of a concrete
// type, you will have to use `#![feature(trait_upcasting)]`, unfortunately.
let handle: AnyHandle<dyn Any> = AnyHandle::new(Box::new(SomeStruct(12)));
// Now we can put it in some sort of generic container...
// ...and when we retrieve it later:
let mut handle: AnyHandle<SomeStruct> = handle.downcast().ok()?;
handle.write().do_mut_things_with();
handle.read().do_things_with();
Some(())
}