Macro-ize Offer accessors for reuse

InvoiceRequest wraps OfferContents, which shouldn't be exposed as it is
an implementation detail. Define a macro for Offer accessor methods so
that InvoiceRequest and UnsignedInvoiceRequest can also define them.

Author: jkczyz

lightning/src/offers/mod.rs

@@ -12,11 +12,13 @@
 //!
 //! Offers are a flexible protocol for Lightning payments.
 
+#[macro_use]
+pub mod offer;
+
 pub mod invoice;
 pub mod invoice_error;
 pub mod invoice_request;
 pub mod merkle;
-pub mod offer;
 pub mod parse;
 mod payer;
 pub mod refund;

lightning/src/offers/offer.rs

@@ -358,77 +358,86 @@ pub(super) struct OfferContents {
 	signing_pubkey: PublicKey,
 }
 
-impl Offer {
+macro_rules! offer_accessors { ($self: ident, $contents: expr) => {
 	// TODO: Return a slice once ChainHash has constants.
 	// - https://github.com/rust-bitcoin/rust-bitcoin/pull/1283
 	// - https://github.com/rust-bitcoin/rust-bitcoin/pull/1286
 	/// The chains that may be used when paying a requested invoice (e.g., bitcoin mainnet).
 	/// Payments must be denominated in units of the minimal lightning-payable unit (e.g., msats)
 	/// for the selected chain.
-	pub fn chains(&self) -> Vec<ChainHash> {
-		self.contents.chains()
-	}
-
-	pub(super) fn implied_chain(&self) -> ChainHash {
-		self.contents.implied_chain()
-	}
-
-	/// Returns whether the given chain is supported by the offer.
-	pub fn supports_chain(&self, chain: ChainHash) -> bool {
-		self.contents.supports_chain(chain)
+	pub fn chains(&$self) -> Vec<$crate::bitcoin::blockdata::constants::ChainHash> {
+		$contents.chains()
 	}
 
 	// TODO: Link to corresponding method in `InvoiceRequest`.
 	/// Opaque bytes set by the originator. Useful for authentication and validating fields since it
 	/// is reflected in `invoice_request` messages along with all the other fields from the `offer`.
-	pub fn metadata(&self) -> Option<&Vec<u8>> {
-		self.contents.metadata()
+	pub fn metadata(&$self) -> Option<&Vec<u8>> {
+		$contents.metadata()
 	}
 
 	/// The minimum amount required for a successful payment of a single item.
-	pub fn amount(&self) -> Option<&Amount> {
-		self.contents.amount()
+	pub fn amount(&$self) -> Option<&$crate::offers::offer::Amount> {
+		$contents.amount()
 	}
 
 	/// A complete description of the purpose of the payment. Intended to be displayed to the user
 	/// but with the caveat that it has not been verified in any way.
-	pub fn description(&self) -> PrintableString {
-		self.contents.description()
+	pub fn description(&$self) -> $crate::util::string::PrintableString {
+		$contents.description()
 	}
 
 	/// Features pertaining to the offer.
-	pub fn features(&self) -> &OfferFeatures {
-		&self.contents.features()
+	pub fn offer_features(&$self) -> &$crate::ln::features::OfferFeatures {
+		&$contents.features()
 	}
 
 	/// Duration since the Unix epoch when an invoice should no longer be requested.
 	///
 	/// If `None`, the offer does not expire.
-	pub fn absolute_expiry(&self) -> Option<Duration> {
-		self.contents.absolute_expiry()
-	}
-
-	/// Whether the offer has expired.
-	#[cfg(feature = "std")]
-	pub fn is_expired(&self) -> bool {
-		self.contents.is_expired()
+	pub fn absolute_expiry(&$self) -> Option<core::time::Duration> {
+		$contents.absolute_expiry()
 	}
 
 	/// The issuer of the offer, possibly beginning with `user@domain` or `domain`. Intended to be
 	/// displayed to the user but with the caveat that it has not been verified in any way.
-	pub fn issuer(&self) -> Option<PrintableString> {
-		self.contents.issuer()
+	pub fn issuer(&$self) -> Option<$crate::util::string::PrintableString> {
+		$contents.issuer()
 	}
 
 	/// Paths to the recipient originating from publicly reachable nodes. Blinded paths provide
 	/// recipient privacy by obfuscating its node id.
-	pub fn paths(&self) -> &[BlindedPath] {
-		self.contents.paths()
+	pub fn paths(&$self) -> &[$crate::blinded_path::BlindedPath] {
+		$contents.paths()
 	}
 
 	/// The quantity of items supported.
-	pub fn supported_quantity(&self) -> Quantity {
-		self.contents.supported_quantity()
+	pub fn supported_quantity(&$self) -> $crate::offers::offer::Quantity {
+		$contents.supported_quantity()
+	}
+
+	/// The public key used by the recipient to sign invoices.
+	pub fn signing_pubkey(&$self) -> $crate::bitcoin::secp256k1::PublicKey {
+		$contents.signing_pubkey()
+	}
+} }
+
+impl Offer {
+	offer_accessors!(self, self.contents);
+
+	pub(super) fn implied_chain(&self) -> ChainHash {
+		self.contents.implied_chain()
+	}
+
+	/// Returns whether the given chain is supported by the offer.
+	pub fn supports_chain(&self, chain: ChainHash) -> bool {
+		self.contents.supports_chain(chain)
+	}
+
+	/// Whether the offer has expired.
+	#[cfg(feature = "std")]
+	pub fn is_expired(&self) -> bool {
+		self.contents.is_expired()
 	}
 
 	/// Returns whether the given quantity is valid for the offer.
@@ -443,11 +452,6 @@ impl Offer {
 		self.contents.expects_quantity()
 	}
 
-	/// The public key used by the recipient to sign invoices.
-	pub fn signing_pubkey(&self) -> PublicKey {
-		self.contents.signing_pubkey()
-	}
-
 	/// Similar to [`Offer::request_invoice`] except it:
 	/// - derives the [`InvoiceRequest::payer_id`] such that a different key can be used for each
 	///   request, and
@@ -469,7 +473,7 @@ impl Offer {
 	where
 		ES::Target: EntropySource,
 	{
-		if self.features().requires_unknown_bits() {
+		if self.offer_features().requires_unknown_bits() {
 			return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 		}
 
@@ -490,7 +494,7 @@ impl Offer {
 	where
 		ES::Target: EntropySource,
 	{
-		if self.features().requires_unknown_bits() {
+		if self.offer_features().requires_unknown_bits() {
 			return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 		}
 
@@ -515,7 +519,7 @@ impl Offer {
 	pub fn request_invoice(
 		&self, metadata: Vec<u8>, payer_id: PublicKey
 	) -> Result<InvoiceRequestBuilder<ExplicitPayerId, secp256k1::SignOnly>, Bolt12SemanticError> {
-		if self.features().requires_unknown_bits() {
+		if self.offer_features().requires_unknown_bits() {
 			return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 		}
 
@@ -890,7 +894,7 @@ mod tests {
 		assert_eq!(offer.metadata(), None);
 		assert_eq!(offer.amount(), None);
 		assert_eq!(offer.description(), PrintableString("foo"));
-		assert_eq!(offer.features(), &OfferFeatures::empty());
+		assert_eq!(offer.offer_features(), &OfferFeatures::empty());
 		assert_eq!(offer.absolute_expiry(), None);
 		#[cfg(feature = "std")]
 		assert!(!offer.is_expired());
@@ -1131,15 +1135,15 @@ mod tests {
 			.features_unchecked(OfferFeatures::unknown())
 			.build()
 			.unwrap();
-		assert_eq!(offer.features(), &OfferFeatures::unknown());
+		assert_eq!(offer.offer_features(), &OfferFeatures::unknown());
 		assert_eq!(offer.as_tlv_stream().features, Some(&OfferFeatures::unknown()));
 
 		let offer = OfferBuilder::new("foo".into(), pubkey(42))
 			.features_unchecked(OfferFeatures::unknown())
 			.features_unchecked(OfferFeatures::empty())
 			.build()
 			.unwrap();
-		assert_eq!(offer.features(), &OfferFeatures::empty());
+		assert_eq!(offer.offer_features(), &OfferFeatures::empty());
 		assert_eq!(offer.as_tlv_stream().features, None);
 	}