WIP: send invoice request encoding

Author: jkczyz

lightning/src/offers/invoice_request.rs

@@ -58,7 +58,7 @@ use io;
 use ln::features::OfferFeatures;
 use ln::msgs::DecodeError;
 use offers::merkle::{SignatureTlvStream, SignatureTlvStreamRef, self};
-use offers::offer::{Amount, Offer, OfferContents, OfferTlvStream, OfferTlvStreamRef};
+use offers::offer::{Amount, Offer, OfferContents, OfferTlvStream, OfferTlvStreamRef, SendInvoiceOfferContents};
 use offers::parse::{ParseError, SemanticError};
 use offers::payer::{PayerContents, PayerTlvStream, PayerTlvStreamRef};
 use util::ser::{HighZeroBytesDroppedBigSize, SeekReadable, WithoutLength, Writeable, Writer};
@@ -412,7 +412,10 @@ impl TryFrom<PartialInvoiceRequestTlvStream> for InvoiceRequestContents {
 		) = tlv_stream;
 
 		let payer = PayerContents(metadata);
-		let offer = OfferContents::try_from(offer_tlv_stream)?;
+		let offer = match offer_tlv_stream.node_id {
+			Some(_) => OfferContents::try_from(offer_tlv_stream)?,
+			None => SendInvoiceOfferContents::try_from(offer_tlv_stream)?.0,
+		};
 
 		if !offer.supports_chain(chain.unwrap_or_else(|| offer.implied_chain())) {
 			return Err(SemanticError::UnsupportedChain);

lightning/src/offers/offer.rs

@@ -596,6 +596,57 @@ impl TryFrom<OfferTlvStream> for OfferContents {
 	}
 }
 
+/// [`OfferContents`] used with a "send invoice" offer (i.e., a published [`InvoiceRequest`]).
+///
+/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
+pub(super) struct SendInvoiceOfferContents(pub OfferContents);
+
+impl TryFrom<OfferTlvStream> for SendInvoiceOfferContents {
+	type Error = SemanticError;
+
+	fn try_from(tlv_stream: OfferTlvStream) -> Result<Self, Self::Error> {
+		let OfferTlvStream {
+			chains, metadata, currency, amount, description, features, absolute_expiry, paths,
+			issuer, quantity_max, node_id,
+		} = tlv_stream;
+		assert!(node_id.is_none());
+
+		if chains.is_some() {
+			return Err(SemanticError::UnexpectedChain);
+		}
+
+		if currency.is_some() || amount.is_some() {
+			return Err(SemanticError::UnexpectedAmount);
+		}
+
+		let description = match description {
+			None => return Err(SemanticError::MissingDescription),
+			Some(description) => description,
+		};
+
+		let features = match features {
+			None => OfferFeatures::empty(),
+			Some(_) => return Err(SemanticError::UnexpectedFeatures),
+		};
+
+		let absolute_expiry = absolute_expiry.map(Duration::from_secs);
+
+		let paths = match paths {
+			Some(paths) if paths.is_empty() => return Err(SemanticError::MissingPaths),
+			paths => paths,
+		};
+
+		if quantity_max.is_some() {
+			return Err(SemanticError::UnexpectedQuantity);
+		}
+
+		Ok(SendInvoiceOfferContents(OfferContents {
+			chains: None, metadata, amount: None, description, features, absolute_expiry, issuer,
+			paths, supported_quantity: Quantity::One, signing_pubkey: None,
+		}))
+	}
+}
+
 impl core::fmt::Display for Offer {
 	fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 		self.fmt_bech32_str(f)

lightning/src/offers/parse.rs

@@ -77,16 +77,23 @@ pub enum ParseError {
 pub enum SemanticError {
 	/// The provided chain hash does not correspond to a supported chain.
 	UnsupportedChain,
+	/// A chain was provided but was not expected.
+	UnexpectedChain,
+	/// An amount was not provided.
 	/// An amount was expected but was missing.
 	MissingAmount,
 	/// An amount exceeded the maximum number of bitcoin.
 	InvalidAmount,
 	/// An amount was provided but was not sufficient in value.
 	InsufficientAmount,
+	/// An amount was provided but was not expected.
+	UnexpectedAmount,
 	/// A currency was provided that is not supported.
 	UnsupportedCurrency,
 	/// A feature was required but is unknown.
 	UnknownRequiredFeatures,
+	/// Features were provided but were not expected.
+	UnexpectedFeatures,
 	/// A required description was not provided.
 	MissingDescription,
 	/// A node id was not provided.