rust: add conversion between sync and async interfaces
Test: add new test
Bug: 207463587
Change-Id: Ib01ffb737c15b1e919d9d87e89a1c47e40723b92
diff --git a/libs/binder/rust/src/binder.rs b/libs/binder/rust/src/binder.rs
index 3d2eddf..4d6b294 100644
--- a/libs/binder/rust/src/binder.rs
+++ b/libs/binder/rust/src/binder.rs
@@ -66,6 +66,35 @@
}
}
+/// Implemented by sync interfaces to specify what the associated async interface is.
+/// Generic to handle the fact that async interfaces are generic over a thread pool.
+///
+/// The binder in any object implementing this trait should be compatible with the
+/// `Target` associated type, and using `FromIBinder` to convert it to the target
+/// should not fail.
+pub trait ToAsyncInterface<P>
+where
+ Self: Interface,
+ Self::Target: FromIBinder,
+{
+ /// The async interface associated with this sync interface.
+ type Target: ?Sized;
+}
+
+/// Implemented by async interfaces to specify what the associated sync interface is.
+///
+/// The binder in any object implementing this trait should be compatible with the
+/// `Target` associated type, and using `FromIBinder` to convert it to the target
+/// should not fail.
+pub trait ToSyncInterface
+where
+ Self: Interface,
+ Self::Target: FromIBinder,
+{
+ /// The sync interface associated with this async interface.
+ type Target: ?Sized;
+}
+
/// Interface stability promise
///
/// An interface can promise to be a stable vendor interface ([`Vintf`]), or
@@ -337,6 +366,26 @@
pub fn downgrade(this: &Strong<I>) -> Weak<I> {
Weak::new(this)
}
+
+ /// Convert this synchronous binder handle into an asynchronous one.
+ pub fn into_async<P>(self) -> Strong<<I as ToAsyncInterface<P>>::Target>
+ where
+ I: ToAsyncInterface<P>,
+ {
+ // By implementing the ToAsyncInterface trait, it is guaranteed that the binder
+ // object is also valid for the target type.
+ FromIBinder::try_from(self.0.as_binder()).unwrap()
+ }
+
+ /// Convert this asynchronous binder handle into a synchronous one.
+ pub fn into_sync(self) -> Strong<<I as ToSyncInterface>::Target>
+ where
+ I: ToSyncInterface,
+ {
+ // By implementing the ToSyncInterface trait, it is guaranteed that the binder
+ // object is also valid for the target type.
+ FromIBinder::try_from(self.0.as_binder()).unwrap()
+ }
}
impl<I: FromIBinder + ?Sized> Clone for Strong<I> {
@@ -1017,6 +1066,14 @@
.expect(concat!("Error cloning interface ", stringify!($async_interface)))
}
}
+
+ impl<P: $crate::BinderAsyncPool> $crate::ToAsyncInterface<P> for dyn $interface {
+ type Target = dyn $async_interface<P>;
+ }
+
+ impl<P: $crate::BinderAsyncPool> $crate::ToSyncInterface for dyn $async_interface<P> {
+ type Target = dyn $interface;
+ }
)?
};
}