f - Make TaggedHash fields pub

Author: jkczyz

lightning/src/offers/invoice.rs

@@ -126,7 +126,8 @@ use std::time::SystemTime;
 
 const DEFAULT_RELATIVE_EXPIRY: Duration = Duration::from_secs(7200);
 
-pub(super) const SIGNATURE_TAG: &'static str = concat!("lightning", "invoice", "signature");
+/// Tag for the hash function used when signing a [`Bolt12Invoice`]'s merkle root.
+pub const SIGNATURE_TAG: &'static str = concat!("lightning", "invoice", "signature");
 
 /// Builds a [`Bolt12Invoice`] from either:
 /// - an [`InvoiceRequest`] for the "offer to be paid" flow or

lightning/src/offers/invoice_request.rs

@@ -76,7 +76,8 @@ use crate::util::string::PrintableString;
 
 use crate::prelude::*;
 
-const SIGNATURE_TAG: &'static str = concat!("lightning", "invoice_request", "signature");
+/// Tag for the hash function used when signing an [`InvoiceRequest`]'s merkle root.
+pub const SIGNATURE_TAG: &'static str = concat!("lightning", "invoice_request", "signature");
 
 pub(super) const IV_BYTES: &[u8; IV_LEN] = b"LDK Invreq ~~~~~";
 

lightning/src/offers/merkle.rs

@@ -33,8 +33,17 @@ tlv_stream!(SignatureTlvStream, SignatureTlvStreamRef, SIGNATURE_TYPES, {
 /// [BIP 340]: https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki
 /// [BOLT 12]: https://github.com/rustyrussell/lightning-rfc/blob/guilt/offers/12-offer-encoding.md#signature-calculation
 pub struct TaggedHash<'a> {
-	tag: &'a str,
-	tlv_stream: &'a [u8],
+	/// Tag used for the hash function as defined in BOLT 12. Typically, either
+	/// [`invoice_request::SIGNATURE_TAG`] or [`invoice::SIGNATURE_TAG`].
+	///
+	/// [`invoice::SIGNATURE_TAG`]: crate::offers::invoice::SIGNATURE_TAG
+	/// [`invoice_request::SIGNATURE_TAG`]: crate::offers::invoice_request::SIGNATURE_TAG
+	pub tag: &'a str,
+
+	/// The TLV stream bytes to compute the tagged hash over.
+	pub tlv_stream: &'a [u8],
+
+	/// The cached digest to sign.
 	digest: RefCell<Option<Message>>,
 }