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//! Data types, functions and traits for `sys` runtime's `ExternRef` implementation.
use std::any::Any;
use wasmer_vm::{StoreHandle, VMExternRef};
use crate::store::{AsStoreMut, AsStoreRef};
#[derive(Debug, Clone)]
#[repr(transparent)]
/// A WebAssembly `extern ref` in the `sys` runtime.
pub(crate) struct ExternRef {
handle: StoreHandle<wasmer_vm::VMExternObj>,
}
impl ExternRef {
/// Make a new extern reference
pub fn new<T>(store: &mut impl AsStoreMut, value: T) -> Self
where
T: Any + Send + Sync + 'static + Sized,
{
Self {
handle: StoreHandle::new(
store.objects_mut().as_sys_mut(),
wasmer_vm::VMExternObj::new(value),
),
}
}
/// Try to downcast to the given value.
pub fn downcast<'a, T>(&self, store: &'a impl AsStoreRef) -> Option<&'a T>
where
T: Any + Send + Sync + 'static + Sized,
{
self.handle
.get(store.as_store_ref().objects().as_sys())
.as_ref()
.downcast_ref::<T>()
}
/// Create a [`VMExternRef`] from [`Self`].
pub(crate) fn vm_externref(&self) -> VMExternRef {
wasmer_vm::VMExternRef(self.handle.internal_handle())
}
/// Create an instance of [`Self`] from a [`VMExternRef`].
pub(crate) unsafe fn from_vm_externref(
store: &mut impl AsStoreMut,
vm_externref: VMExternRef,
) -> Self {
Self {
handle: unsafe { StoreHandle::from_internal(store.objects_mut().id(), vm_externref.0) },
}
}
/// Checks whether this `ExternRef` can be used with the given context.
///
/// Primitive (`i32`, `i64`, etc) and null funcref/externref values are not
/// tied to a context and can be freely shared between contexts.
///
/// Externref and funcref values are tied to a context and can only be used
/// with that context.
pub fn is_from_store(&self, store: &impl AsStoreRef) -> bool {
self.handle.store_id() == store.as_store_ref().objects().id()
}
}