Fix (and DRY) the conditionals before calling `peer_disconnected`
[rust-lightning] / lightning / src / offers / refund.rs
index d3798463b440ed6c0bead3034392671aa57b5555..fff33873954a6f92ab55ad2de8d326447dafd0ac 100644 (file)
 //! Data structures and encoding for refunds.
 //!
 //! A [`Refund`] is an "offer for money" and is typically constructed by a merchant and presented
-//! directly to the customer. The recipient responds with an `Invoice` to be paid.
+//! directly to the customer. The recipient responds with an [`Invoice`] to be paid.
 //!
 //! This is an [`InvoiceRequest`] produced *not* in response to an [`Offer`].
 //!
+//! [`Invoice`]: crate::offers::invoice::Invoice
 //! [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 //! [`Offer`]: crate::offers::offer::Offer
 //!
@@ -77,8 +78,10 @@ use core::convert::TryFrom;
 use core::str::FromStr;
 use core::time::Duration;
 use crate::io;
+use crate::ln::PaymentHash;
 use crate::ln::features::InvoiceRequestFeatures;
 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
+use crate::offers::invoice::{BlindedPayInfo, InvoiceBuilder};
 use crate::offers::invoice_request::{InvoiceRequestTlvStream, InvoiceRequestTlvStreamRef};
 use crate::offers::offer::{OfferTlvStream, OfferTlvStreamRef};
 use crate::offers::parse::{Bech32Encode, ParseError, ParsedMessage, SemanticError};
@@ -115,9 +118,9 @@ impl RefundBuilder {
                }
 
                let refund = RefundContents {
-                       payer: PayerContents(metadata), metadata: None, description, absolute_expiry: None,
-                       issuer: None, paths: None, chain: None, amount_msats,
-                       features: InvoiceRequestFeatures::empty(), payer_id, payer_note: None,
+                       payer: PayerContents(metadata), description, absolute_expiry: None, issuer: None,
+                       paths: None, chain: None, amount_msats, features: InvoiceRequestFeatures::empty(),
+                       quantity: None, payer_id, payer_note: None,
                };
 
                Ok(RefundBuilder { refund })
@@ -159,6 +162,20 @@ impl RefundBuilder {
                self
        }
 
+       /// Sets [`Refund::quantity`] of items. This is purely for informational purposes. It is useful
+       /// when the refund pertains to an [`Invoice`] that paid for more than one item from an
+       /// [`Offer`] as specified by [`InvoiceRequest::quantity`].
+       ///
+       /// Successive calls to this method will override the previous setting.
+       ///
+       /// [`Invoice`]: crate::offers::invoice::Invoice
+       /// [`InvoiceRequest::quantity`]: crate::offers::invoice_request::InvoiceRequest::quantity
+       /// [`Offer`]: crate::offers::offer::Offer
+       pub fn quantity(mut self, quantity: u64) -> Self {
+               self.refund.quantity = Some(quantity);
+               self
+       }
+
        /// Sets the [`Refund::payer_note`].
        ///
        /// Successive calls to this method will override the previous setting.
@@ -191,25 +208,27 @@ impl RefundBuilder {
        }
 }
 
-/// A `Refund` is a request to send an `Invoice` without a preceding [`Offer`].
+/// A `Refund` is a request to send an [`Invoice`] without a preceding [`Offer`].
 ///
 /// Typically, after an invoice is paid, the recipient may publish a refund allowing the sender to
 /// recoup their funds. A refund may be used more generally as an "offer for money", such as with a
 /// bitcoin ATM.
 ///
+/// [`Invoice`]: crate::offers::invoice::Invoice
 /// [`Offer`]: crate::offers::offer::Offer
 #[derive(Clone, Debug)]
 pub struct Refund {
-       bytes: Vec<u8>,
-       contents: RefundContents,
+       pub(super) bytes: Vec<u8>,
+       pub(super) contents: RefundContents,
 }
 
-/// The contents of a [`Refund`], which may be shared with an `Invoice`.
+/// The contents of a [`Refund`], which may be shared with an [`Invoice`].
+///
+/// [`Invoice`]: crate::offers::invoice::Invoice
 #[derive(Clone, Debug)]
-struct RefundContents {
+pub(super) struct RefundContents {
        payer: PayerContents,
        // offer fields
-       metadata: Option<Vec<u8>>,
        description: String,
        absolute_expiry: Option<Duration>,
        issuer: Option<String>,
@@ -218,6 +237,7 @@ struct RefundContents {
        chain: Option<ChainHash>,
        amount_msats: u64,
        features: InvoiceRequestFeatures,
+       quantity: Option<u64>,
        payer_id: PublicKey,
        payer_note: Option<String>,
 }
@@ -239,13 +259,7 @@ impl Refund {
        /// Whether the refund has expired.
        #[cfg(feature = "std")]
        pub fn is_expired(&self) -> bool {
-               match self.absolute_expiry() {
-                       Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
-                               Ok(elapsed) => elapsed > seconds_from_epoch,
-                               Err(_) => false,
-                       },
-                       None => false,
-               }
+               self.contents.is_expired()
        }
 
        /// The issuer of the refund, possibly beginning with `user@domain` or `domain`. Intended to be
@@ -285,6 +299,11 @@ impl Refund {
                &self.contents.features
        }
 
+       /// The quantity of an item that refund is for.
+       pub fn quantity(&self) -> Option<u64> {
+               self.contents.quantity
+       }
+
        /// A public node id to send to in the case where there are no [`paths`]. Otherwise, a possibly
        /// transient pubkey.
        ///
@@ -298,6 +317,46 @@ impl Refund {
                self.contents.payer_note.as_ref().map(|payer_note| PrintableString(payer_note.as_str()))
        }
 
+       /// Creates an [`Invoice`] for the refund with the given required fields.
+       ///
+       /// Unless [`InvoiceBuilder::relative_expiry`] is set, the invoice will expire two hours after
+       /// calling this method in `std` builds. For `no-std` builds, a final [`Duration`] parameter
+       /// must be given, which is used to set [`Invoice::created_at`] since [`std::time::SystemTime`]
+       /// is not available.
+       ///
+       /// The caller is expected to remember the preimage of `payment_hash` in order to
+       /// claim a payment for the invoice.
+       ///
+       /// The `signing_pubkey` is required to sign the invoice since refunds are not in response to an
+       /// offer, which does have a `signing_pubkey`.
+       ///
+       /// The `payment_paths` parameter is useful for maintaining the payment recipient's privacy. It
+       /// must contain one or more elements ordered from most-preferred to least-preferred, if there's
+       /// a preference. Note, however, that any privacy is lost if a public node id is used for
+       /// `signing_pubkey`.
+       ///
+       /// Errors if the request contains unknown required features.
+       ///
+       /// [`Invoice`]: crate::offers::invoice::Invoice
+       /// [`Invoice::created_at`]: crate::offers::invoice::Invoice::created_at
+       pub fn respond_with(
+               &self, payment_paths: Vec<(BlindedPath, BlindedPayInfo)>, payment_hash: PaymentHash,
+               signing_pubkey: PublicKey,
+               #[cfg(any(test, not(feature = "std")))]
+               created_at: Duration
+       ) -> Result<InvoiceBuilder, SemanticError> {
+               if self.features().requires_unknown_bits() {
+                       return Err(SemanticError::UnknownRequiredFeatures);
+               }
+
+               #[cfg(all(not(test), feature = "std"))]
+               let created_at = std::time::SystemTime::now()
+                       .duration_since(std::time::SystemTime::UNIX_EPOCH)
+                       .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
+
+               InvoiceBuilder::for_refund(self, payment_paths, created_at, payment_hash, signing_pubkey)
+       }
+
        #[cfg(test)]
        fn as_tlv_stream(&self) -> RefundTlvStreamRef {
                self.contents.as_tlv_stream()
@@ -311,7 +370,18 @@ impl AsRef<[u8]> for Refund {
 }
 
 impl RefundContents {
-       fn chain(&self) -> ChainHash {
+       #[cfg(feature = "std")]
+       pub(super) fn is_expired(&self) -> bool {
+               match self.absolute_expiry {
+                       Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
+                               Ok(elapsed) => elapsed > seconds_from_epoch,
+                               Err(_) => false,
+                       },
+                       None => false,
+               }
+       }
+
+       pub(super) fn chain(&self) -> ChainHash {
                self.chain.unwrap_or_else(|| self.implied_chain())
        }
 
@@ -326,7 +396,7 @@ impl RefundContents {
 
                let offer = OfferTlvStreamRef {
                        chains: None,
-                       metadata: self.metadata.as_ref(),
+                       metadata: None,
                        currency: None,
                        amount: None,
                        description: Some(&self.description),
@@ -347,7 +417,7 @@ impl RefundContents {
                        chain: self.chain.as_ref(),
                        amount: Some(self.amount_msats),
                        features,
-                       quantity: None,
+                       quantity: self.quantity,
                        payer_id: Some(&self.payer_id),
                        payer_note: self.payer_note.as_ref(),
                };
@@ -428,6 +498,10 @@ impl TryFrom<RefundTlvStream> for RefundContents {
                        Some(metadata) => PayerContents(metadata),
                };
 
+               if metadata.is_some() {
+                       return Err(SemanticError::UnexpectedMetadata);
+               }
+
                if chains.is_some() {
                        return Err(SemanticError::UnexpectedChain);
                }
@@ -465,20 +539,14 @@ impl TryFrom<RefundTlvStream> for RefundContents {
 
                let features = features.unwrap_or_else(InvoiceRequestFeatures::empty);
 
-               // TODO: Check why this isn't in the spec.
-               if quantity.is_some() {
-                       return Err(SemanticError::UnexpectedQuantity);
-               }
-
                let payer_id = match payer_id {
                        None => return Err(SemanticError::MissingPayerId),
                        Some(payer_id) => payer_id,
                };
 
-               // TODO: Should metadata be included?
                Ok(RefundContents {
-                       payer, metadata, description, absolute_expiry, issuer, paths, chain, amount_msats,
-                       features, payer_id, payer_note,
+                       payer, description, absolute_expiry, issuer, paths, chain, amount_msats, features,
+                       quantity, payer_id, payer_note,
                })
        }
 }
@@ -706,6 +774,24 @@ mod tests {
                assert_eq!(tlv_stream.chain, Some(&testnet));
        }
 
+       #[test]
+       fn builds_refund_with_quantity() {
+               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+                       .quantity(10)
+                       .build().unwrap();
+               let (_, _, tlv_stream) = refund.as_tlv_stream();
+               assert_eq!(refund.quantity(), Some(10));
+               assert_eq!(tlv_stream.quantity, Some(10));
+
+               let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
+                       .quantity(10)
+                       .quantity(1)
+                       .build().unwrap();
+               let (_, _, tlv_stream) = refund.as_tlv_stream();
+               assert_eq!(refund.quantity(), Some(1));
+               assert_eq!(tlv_stream.quantity, Some(1));
+       }
+
        #[test]
        fn builds_refund_with_payer_note() {
                let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
@@ -839,6 +925,7 @@ mod tests {
                        .path(paths[1].clone())
                        .chain(Network::Testnet)
                        .features_unchecked(InvoiceRequestFeatures::unknown())
+                       .quantity(10)
                        .payer_note("baz".into())
                        .build()
                        .unwrap();
@@ -851,6 +938,7 @@ mod tests {
                                assert_eq!(refund.issuer(), Some(PrintableString("bar")));
                                assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Testnet));
                                assert_eq!(refund.features(), &InvoiceRequestFeatures::unknown());
+                               assert_eq!(refund.quantity(), Some(10));
                                assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
                        },
                        Err(e) => panic!("error parsing refund: {:?}", e),
@@ -865,6 +953,17 @@ mod tests {
                        panic!("error parsing refund: {:?}", e);
                }
 
+               let metadata = vec![42; 32];
+               let mut tlv_stream = refund.as_tlv_stream();
+               tlv_stream.1.metadata = Some(&metadata);
+
+               match Refund::try_from(tlv_stream.to_bytes()) {
+                       Ok(_) => panic!("expected error"),
+                       Err(e) => {
+                               assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedMetadata));
+                       },
+               }
+
                let chains = vec![ChainHash::using_genesis_block(Network::Testnet)];
                let mut tlv_stream = refund.as_tlv_stream();
                tlv_stream.1.chains = Some(&chains);
@@ -918,16 +1017,6 @@ mod tests {
                                assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedSigningPubkey));
                        },
                }
-
-               let mut tlv_stream = refund.as_tlv_stream();
-               tlv_stream.2.quantity = Some(10);
-
-               match Refund::try_from(tlv_stream.to_bytes()) {
-                       Ok(_) => panic!("expected error"),
-                       Err(e) => {
-                               assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedQuantity));
-                       },
-               }
        }
 
        #[test]