Add downcast_ref to AnyViewHandle

I use unsafe code to transmute an AnyViewHandle to a ViewHandle<T> when
the type matches. Because ViewHandle<T> is repr(transparent) to the
wrapped AnyViewHandle, this is safe.
This commit is contained in:
Nathan Sobo 2023-04-02 16:10:16 -06:00
parent 71cf6ec5ae
commit 138aa0492a
4 changed files with 15 additions and 12 deletions

View File

@ -353,8 +353,7 @@ mod tests {
assert_eq!(
active_item
.as_any()
.clone()
.downcast::<Editor>()
.downcast_ref::<Editor>()
.unwrap()
.read(cx)
.title(cx),

View File

@ -4661,6 +4661,7 @@ impl<T> Clone for WeakModelHandle<T> {
impl<T> Copy for WeakModelHandle<T> {}
#[repr(transparent)]
pub struct ViewHandle<T> {
any_handle: AnyViewHandle,
view_type: PhantomData<T>,
@ -4877,6 +4878,14 @@ impl AnyViewHandle {
}
}
pub fn downcast_ref<T: View>(&self) -> Option<&ViewHandle<T>> {
if self.is::<T>() {
Some(unsafe { mem::transmute(self) })
} else {
None
}
}
pub fn downgrade(&self) -> AnyWeakViewHandle {
AnyWeakViewHandle {
window_id: self.window_id,

View File

@ -2279,8 +2279,7 @@ mod tests {
.map(|(ix, item)| {
let mut state = item
.as_any()
.clone()
.downcast::<TestItem>()
.downcast_ref::<TestItem>()
.unwrap()
.read(cx)
.label

View File

@ -1021,8 +1021,7 @@ mod tests {
.active_item()
.unwrap()
.as_any()
.clone()
.downcast::<Editor>()
.downcast_ref::<Editor>()
.unwrap()
.read(cx)
.title(cx),
@ -1058,8 +1057,7 @@ mod tests {
.active_item()
.unwrap()
.as_any()
.clone()
.downcast::<Editor>()
.downcast_ref::<Editor>()
.unwrap()
.read(cx)
.title(cx),
@ -1095,8 +1093,7 @@ mod tests {
.active_item()
.unwrap()
.as_any()
.clone()
.downcast::<Editor>()
.downcast_ref::<Editor>()
.unwrap()
.read(cx)
.title(cx),
@ -1146,8 +1143,7 @@ mod tests {
.active_item()
.unwrap()
.as_any()
.clone()
.downcast::<Editor>()
.downcast_ref::<Editor>()
.unwrap()
.read(cx)
.title(cx),