util: Adds Into<PaymentHash> for PaymentPreimage

This seems like a useful interface to have for downstream users

Author: sr-gi

lightning/src/ln/mod.rs

@@ -34,6 +34,7 @@ pub mod channel;
 #[cfg(not(fuzzing))]
 pub(crate) mod channel;
 
+use bitcoin::secp256k1::ThirtyTwoByteHash;
 // Re-export ChannelId
 pub use channel_id::ChannelId;
 
@@ -85,6 +86,8 @@ mod offers_tests;
 
 pub use self::peer_channel_encryptor::LN_MAX_MSG_LEN;
 
+use bitcoin::hashes::{sha256::Hash as Sha256, Hash};
+
 /// payment_hash type, use to cross-lock hop
 ///
 /// This is not exported to bindings users as we just use [u8; 32] directly
@@ -109,6 +112,12 @@ impl core::fmt::Display for PaymentPreimage {
 	}
 }
 
+impl Into<PaymentHash> for PaymentPreimage {
+	fn into(self) -> PaymentHash {
+		PaymentHash(Sha256::hash(&self.0).into_32())
+	}
+}
+
 /// payment_secret type, use to authenticate sender to the receiver and tie MPP HTLCs together
 ///
 /// This is not exported to bindings users as we just use [u8; 32] directly