BOLT 12 invoice: expose common helper methods and fields

Useful for static invoice support.

Author: valentinewallace

lightning/src/offers/invoice.rs

@@ -200,7 +200,7 @@ pub struct ExplicitSigningPubkey {}
 /// [`Bolt12Invoice::signing_pubkey`] was derived.
 ///
 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
-pub struct DerivedSigningPubkey(Keypair);
+pub struct DerivedSigningPubkey(pub(super) Keypair);
 
 impl SigningPubkeyStrategy for ExplicitSigningPubkey {}
 impl SigningPubkeyStrategy for DerivedSigningPubkey {}
@@ -958,14 +958,7 @@ impl InvoiceContents {
 
 	#[cfg(feature = "std")]
 	fn is_expired(&self) -> bool {
-		let absolute_expiry = self.created_at().checked_add(self.relative_expiry());
-		match absolute_expiry {
-			Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
-				Ok(elapsed) => elapsed > seconds_from_epoch,
-				Err(_) => false,
-			},
-			None => false,
-		}
+		is_expired(self.created_at(), self.relative_expiry())
 	}
 
 	fn payment_hash(&self) -> PaymentHash {
@@ -977,36 +970,9 @@ impl InvoiceContents {
 	}
 
 	fn fallbacks(&self) -> Vec<Address> {
-		let chain = self.chain();
-		let network = if chain == ChainHash::using_genesis_block(Network::Bitcoin) {
-			Network::Bitcoin
-		} else if chain == ChainHash::using_genesis_block(Network::Testnet) {
-			Network::Testnet
-		} else if chain == ChainHash::using_genesis_block(Network::Signet) {
-			Network::Signet
-		} else if chain == ChainHash::using_genesis_block(Network::Regtest) {
-			Network::Regtest
-		} else {
-			return Vec::new()
-		};
-
-		let to_valid_address = |address: &FallbackAddress| {
-			let version = match WitnessVersion::try_from(address.version) {
-				Ok(version) => version,
-				Err(_) => return None,
-			};
-
-			let program = address.program.clone();
-			let witness_program = match WitnessProgram::new(version, program) {
-				Ok(witness_program) => witness_program,
-				Err(_) => return None,
-			};
-			Some(Address::new(network, Payload::WitnessProgram(witness_program)))
-		};
-
 		self.fields().fallbacks
 			.as_ref()
-			.map(|fallbacks| fallbacks.iter().filter_map(to_valid_address).collect())
+			.map(|fallbacks| filter_fallbacks(self.chain(), fallbacks))
 			.unwrap_or_else(Vec::new)
 	}
 
@@ -1075,6 +1041,50 @@ impl InvoiceContents {
 	}
 }
 
+#[cfg(feature = "std")]
+pub(super) fn is_expired(created_at: Duration, relative_expiry: Duration) -> bool {
+	let absolute_expiry = created_at.checked_add(relative_expiry);
+	match absolute_expiry {
+		Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
+			Ok(elapsed) => elapsed > seconds_from_epoch,
+			Err(_) => false,
+		},
+		None => false,
+	}
+}
+
+pub(super) fn filter_fallbacks(
+	chain: ChainHash, fallbacks: &Vec<FallbackAddress>
+) -> Vec<Address> {
+	let network = if chain == ChainHash::using_genesis_block(Network::Bitcoin) {
+		Network::Bitcoin
+	} else if chain == ChainHash::using_genesis_block(Network::Testnet) {
+		Network::Testnet
+	} else if chain == ChainHash::using_genesis_block(Network::Signet) {
+		Network::Signet
+	} else if chain == ChainHash::using_genesis_block(Network::Regtest) {
+		Network::Regtest
+	} else {
+		return Vec::new()
+	};
+
+	let to_valid_address = |address: &FallbackAddress| {
+		let version = match WitnessVersion::try_from(address.version) {
+			Ok(version) => version,
+			Err(_) => return None,
+		};
+
+		let program = address.program.clone();
+		let witness_program = match WitnessProgram::new(version, program) {
+			Ok(witness_program) => witness_program,
+			Err(_) => return None,
+		};
+		Some(Address::new(network, Payload::WitnessProgram(witness_program)))
+	};
+
+	fallbacks.iter().filter_map(to_valid_address).collect()
+}
+
 impl InvoiceFields {
 	fn as_tlv_stream(&self) -> InvoiceTlvStreamRef {
 		let features = {
@@ -1154,12 +1164,12 @@ tlv_stream!(InvoiceTlvStream, InvoiceTlvStreamRef, 160..240, {
 	(176, node_id: PublicKey),
 });
 
-type BlindedPathIter<'a> = core::iter::Map<
+pub(super) type BlindedPathIter<'a> = core::iter::Map<
 	core::slice::Iter<'a, (BlindedPayInfo, BlindedPath)>,
 	for<'r> fn(&'r (BlindedPayInfo, BlindedPath)) -> &'r BlindedPath,
 >;
 
-type BlindedPayInfoIter<'a> = core::iter::Map<
+pub(super) type BlindedPayInfoIter<'a> = core::iter::Map<
 	core::slice::Iter<'a, (BlindedPayInfo, BlindedPath)>,
 	for<'r> fn(&'r (BlindedPayInfo, BlindedPath)) -> &'r BlindedPayInfo,
 >;
@@ -1205,8 +1215,8 @@ impl_writeable!(BlindedPayInfo, {
 /// Wire representation for an on-chain fallback address.
 #[derive(Clone, Debug, PartialEq)]
 pub(super) struct FallbackAddress {
-	version: u8,
-	program: Vec<u8>,
+	pub(super) version: u8,
+	pub(super) program: Vec<u8>,
 }
 
 impl_writeable!(FallbackAddress, { version, program });
@@ -1294,17 +1304,7 @@ impl TryFrom<PartialInvoiceTlvStream> for InvoiceContents {
 			},
 		) = tlv_stream;
 
-		let payment_paths = match (blindedpay, paths) {
-			(_, None) => return Err(Bolt12SemanticError::MissingPaths),
-			(None, _) => return Err(Bolt12SemanticError::InvalidPayInfo),
-			(_, Some(paths)) if paths.is_empty() => return Err(Bolt12SemanticError::MissingPaths),
-			(Some(blindedpay), Some(paths)) if paths.len() != blindedpay.len() => {
-				return Err(Bolt12SemanticError::InvalidPayInfo);
-			},
-			(Some(blindedpay), Some(paths)) => {
-				blindedpay.into_iter().zip(paths.into_iter()).collect::<Vec<_>>()
-			},
-		};
+		let payment_paths = construct_payment_paths(blindedpay, paths)?;
 
 		let created_at = match created_at {
 			None => return Err(Bolt12SemanticError::MissingCreationTime),
@@ -1372,6 +1372,22 @@ impl TryFrom<PartialInvoiceTlvStream> for InvoiceContents {
 	}
 }
 
+pub(super) fn construct_payment_paths(
+	blinded_payinfos: Option<Vec<BlindedPayInfo>>, blinded_paths: Option<Vec<BlindedPath>>
+) -> Result<Vec<(BlindedPayInfo, BlindedPath)>, Bolt12SemanticError> {
+	match (blinded_payinfos, blinded_paths) {
+		(_, None) => Err(Bolt12SemanticError::MissingPaths),
+		(None, _) => Err(Bolt12SemanticError::InvalidPayInfo),
+		(_, Some(paths)) if paths.is_empty() => Err(Bolt12SemanticError::MissingPaths),
+		(Some(blindedpay), Some(paths)) if paths.len() != blindedpay.len() => {
+			Err(Bolt12SemanticError::InvalidPayInfo)
+		},
+		(Some(blindedpay), Some(paths)) => {
+			Ok(blindedpay.into_iter().zip(paths.into_iter()).collect::<Vec<_>>())
+		},
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::{Bolt12Invoice, DEFAULT_RELATIVE_EXPIRY, FallbackAddress, FullInvoiceTlvStreamRef, InvoiceTlvStreamRef, SIGNATURE_TAG, UnsignedBolt12Invoice};