+ Ok(self.build_without_checks())
+ }
+
+ fn build_without_checks(mut self) ->
+ (UnsignedInvoiceRequest<'a>, Option<KeyPair>, Option<&'b Secp256k1<T>>)
+ {
+ // Create the metadata for stateless verification of an Invoice.
+ let mut keys = None;
+ let secp_ctx = self.secp_ctx.clone();
+ if self.invoice_request.payer.0.has_derivation_material() {
+ let mut metadata = core::mem::take(&mut self.invoice_request.payer.0);
+
+ let mut tlv_stream = self.invoice_request.as_tlv_stream();
+ debug_assert!(tlv_stream.2.payer_id.is_none());
+ tlv_stream.0.metadata = None;
+ if !metadata.derives_keys() {
+ tlv_stream.2.payer_id = self.payer_id.as_ref();
+ }
+
+ let (derived_metadata, derived_keys) = metadata.derive_from(tlv_stream, self.secp_ctx);
+ metadata = derived_metadata;
+ keys = derived_keys;
+ if let Some(keys) = keys {
+ debug_assert!(self.payer_id.is_none());
+ self.payer_id = Some(keys.public_key());
+ }
+
+ self.invoice_request.payer.0 = metadata;
+ }
+
+ debug_assert!(self.invoice_request.payer.0.as_bytes().is_some());
+ debug_assert!(self.payer_id.is_some());
+ let payer_id = self.payer_id.unwrap();
+
+ let unsigned_invoice = UnsignedInvoiceRequest {
+ offer: self.offer,
+ invoice_request: InvoiceRequestContents {
+ inner: self.invoice_request,
+ payer_id,
+ },
+ };
+
+ (unsigned_invoice, keys, secp_ctx)
+ }
+}
+
+impl<'a, 'b, T: secp256k1::Signing> InvoiceRequestBuilder<'a, 'b, ExplicitPayerId, T> {
+ /// Builds an unsigned [`InvoiceRequest`] after checking for valid semantics. It can be signed
+ /// by [`UnsignedInvoiceRequest::sign`].
+ pub fn build(self) -> Result<UnsignedInvoiceRequest<'a>, SemanticError> {
+ let (unsigned_invoice_request, keys, _) = self.build_with_checks()?;
+ debug_assert!(keys.is_none());
+ Ok(unsigned_invoice_request)
+ }
+}
+
+impl<'a, 'b, T: secp256k1::Signing> InvoiceRequestBuilder<'a, 'b, DerivedPayerId, T> {
+ /// Builds a signed [`InvoiceRequest`] after checking for valid semantics.
+ pub fn build_and_sign(self) -> Result<InvoiceRequest, SemanticError> {
+ let (unsigned_invoice_request, keys, secp_ctx) = self.build_with_checks()?;
+ debug_assert!(keys.is_some());
+
+ let secp_ctx = secp_ctx.unwrap();
+ let keys = keys.unwrap();
+ let invoice_request = unsigned_invoice_request
+ .sign::<_, Infallible>(|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &keys)))
+ .unwrap();
+ Ok(invoice_request)