add sync wrapper

Author: joostjager

lightning/src/sign/mod.rs

@@ -996,6 +996,24 @@ pub trait ChangeDestinationSource {
 	fn get_change_destination_script<'a>(&self) -> AsyncGetChangeDestinationScriptResult<'a, ScriptBuf>;
 }
 
+
+/// A synchronous helper trait that describes an on-chain wallet capable of returning a (change) destination script.
+pub trait ChangeDestinationSourceSync {
+	/// This method should return a different value each time it is called, to avoid linking
+	/// on-chain funds controlled to the same user.
+	fn get_change_destination_script(&self) -> Result<ScriptBuf, ()>;
+}
+
+/// A wrapper around [`ChangeDestinationSource`] to allow for async calls.
+pub struct ChangeDestinationSourceSyncWrapper<T>(T) where T: ChangeDestinationSourceSync;
+
+impl<T: ChangeDestinationSourceSync> ChangeDestinationSource for ChangeDestinationSourceSyncWrapper<T> {
+	fn get_change_destination_script<'a>(&self) -> AsyncGetChangeDestinationScriptResult<'a, ScriptBuf> {
+		let script = self.0.get_change_destination_script();
+		Box::pin(async move { script })
+	}
+}
+
 mod sealed {
 	use bitcoin::secp256k1::{Scalar, SecretKey};