wasmtime_runtime/
store_box.rs

1/// A `Box<T>` lookalike for memory that's stored in a `Store<T>`
2///
3/// This is intended to be quite similar to a `Box<T>` except without the
4/// `Deref` implementations. The main motivation for this type's existence is to
5/// appease the aliasing rules in miri to ensure that `StoreBox` can be moved
6/// around without invalidating pointers to the contents within the box. The
7/// standard `Box<T>` type does not implement this for example and moving that
8/// will invalidate derived pointers.
9pub struct StoreBox<T: ?Sized>(*mut T);
10
11unsafe impl<T: Send + ?Sized> Send for StoreBox<T> {}
12unsafe impl<T: Sync + ?Sized> Sync for StoreBox<T> {}
13
14impl<T> StoreBox<T> {
15    /// Allocates space on the heap to store `val` and returns a pointer to it
16    /// living on the heap.
17    pub fn new(val: T) -> StoreBox<T> {
18        StoreBox(Box::into_raw(Box::new(val)))
19    }
20}
21
22impl<T: ?Sized> StoreBox<T> {
23    /// Returns the underlying pointer to `T` which is owned by the store.
24    pub fn get(&self) -> *mut T {
25        self.0
26    }
27}
28
29impl<T: ?Sized> Drop for StoreBox<T> {
30    fn drop(&mut self) {
31        unsafe {
32            drop(Box::from_raw(self.0));
33        }
34    }
35}
wasmtime_runtime/store_box.rs

wasmtime_runtime/
store_box.rs
