diff options
Diffstat (limited to '')
-rw-r--r-- | third_party/rust/oneshot-uniffi/src/lib.rs | 51 |
1 files changed, 50 insertions, 1 deletions
diff --git a/third_party/rust/oneshot-uniffi/src/lib.rs b/third_party/rust/oneshot-uniffi/src/lib.rs index 94bb35d12a..8da012b8c0 100644 --- a/third_party/rust/oneshot-uniffi/src/lib.rs +++ b/third_party/rust/oneshot-uniffi/src/lib.rs @@ -314,6 +314,31 @@ impl<T> Sender<T> { _ => unreachable!(), } } + + /// Consumes the Sender, returning a raw pointer to the channel on the heap. + /// + /// This is intended to simplify using oneshot channels with some FFI code. The only safe thing + /// to do with the returned pointer is to later reconstruct the Sender with [Sender::from_raw]. + /// Memory will leak if the Sender is never reconstructed. + pub fn into_raw(self) -> *mut () { + let raw = self.channel_ptr.as_ptr() as *mut (); + mem::forget(self); + raw + } + + /// Consumes a raw pointer from [Sender::into_raw], recreating the Sender. + /// + /// # Safety + /// + /// This pointer must have come from [`Sender<T>::into_raw`] with the same message type, `T`. + /// At most one Sender must exist for a channel at any point in time. + /// Constructing multiple Senders from the same raw pointer leads to undefined behavior. + pub unsafe fn from_raw(raw: *mut ()) -> Self { + Self { + channel_ptr: NonNull::new_unchecked(raw as *mut Channel<T>), + _invariant: PhantomData, + } + } } impl<T> Drop for Sender<T> { @@ -816,6 +841,30 @@ impl<T> Receiver<T> { _ => unreachable!(), } } + + /// Consumes the Receiver, returning a raw pointer to the channel on the heap. + /// + /// This is intended to simplify using oneshot channels with some FFI code. The only safe thing + /// to do with the returned pointer is to later reconstruct the Receiver with + /// [Receiver::from_raw]. Memory will leak if the Receiver is never reconstructed. + pub fn into_raw(self) -> *mut () { + let raw = self.channel_ptr.as_ptr() as *mut (); + mem::forget(self); + raw + } + + /// Consumes a raw pointer from [Receiver::into_raw], recreating the Receiver. + /// + /// # Safety + /// + /// This pointer must have come from [`Receiver<T>::into_raw`] with the same message type, `T`. + /// At most one Receiver must exist for a channel at any point in time. + /// Constructing multiple Receivers from the same raw pointer leads to undefined behavior. + pub unsafe fn from_raw(raw: *mut ()) -> Self { + Self { + channel_ptr: NonNull::new_unchecked(raw as *mut Channel<T>), + } + } } #[cfg(feature = "async")] @@ -1178,7 +1227,7 @@ fn receiver_waker_size() { (false, false) => 0, (false, true) => 16, (true, false) => 8, - (true, true) => 24, + (true, true) => 16, }; assert_eq!(mem::size_of::<ReceiverWaker>(), expected); } |