+/// Stores the session_priv for each part of a payment that is still pending. For versions 0.0.102
+/// and later, also stores information for retrying the payment.
+pub(crate) enum PendingOutboundPayment {
+ Legacy {
+ session_privs: HashSet<[u8; 32]>,
+ },
+ Retryable {
+ session_privs: HashSet<[u8; 32]>,
+ payment_hash: PaymentHash,
+ payment_secret: Option<PaymentSecret>,
+ pending_amt_msat: u64,
+ /// Used to track the fee paid. Only present if the payment was serialized on 0.0.103+.
+ pending_fee_msat: Option<u64>,
+ /// The total payment amount across all paths, used to verify that a retry is not overpaying.
+ total_msat: u64,
+ /// Our best known block height at the time this payment was initiated.
+ starting_block_height: u32,
+ },
+ /// When a pending payment is fulfilled, we continue tracking it until all pending HTLCs have
+ /// been resolved. This ensures we don't look up pending payments in ChannelMonitors on restart
+ /// and add a pending payment that was already fulfilled.
+ Fulfilled {
+ session_privs: HashSet<[u8; 32]>,
+ },
+}
+
+impl PendingOutboundPayment {
+ fn is_retryable(&self) -> bool {
+ match self {
+ PendingOutboundPayment::Retryable { .. } => true,
+ _ => false,
+ }
+ }
+ fn is_fulfilled(&self) -> bool {
+ match self {
+ PendingOutboundPayment::Fulfilled { .. } => true,
+ _ => false,
+ }
+ }
+ fn get_pending_fee_msat(&self) -> Option<u64> {
+ match self {
+ PendingOutboundPayment::Retryable { pending_fee_msat, .. } => pending_fee_msat.clone(),
+ _ => None,
+ }
+ }
+
+ fn mark_fulfilled(&mut self) {
+ let mut session_privs = HashSet::new();
+ core::mem::swap(&mut session_privs, match self {
+ PendingOutboundPayment::Legacy { session_privs } |
+ PendingOutboundPayment::Retryable { session_privs, .. } |
+ PendingOutboundPayment::Fulfilled { session_privs }
+ => session_privs
+ });
+ *self = PendingOutboundPayment::Fulfilled { session_privs };
+ }
+
+ /// panics if path is None and !self.is_fulfilled
+ fn remove(&mut self, session_priv: &[u8; 32], path: Option<&Vec<RouteHop>>) -> bool {
+ let remove_res = match self {
+ PendingOutboundPayment::Legacy { session_privs } |
+ PendingOutboundPayment::Retryable { session_privs, .. } |
+ PendingOutboundPayment::Fulfilled { session_privs } => {
+ session_privs.remove(session_priv)
+ }
+ };
+ if remove_res {
+ if let PendingOutboundPayment::Retryable { ref mut pending_amt_msat, ref mut pending_fee_msat, .. } = self {
+ let path = path.expect("Fulfilling a payment should always come with a path");
+ let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
+ *pending_amt_msat -= path_last_hop.fee_msat;
+ if let Some(fee_msat) = pending_fee_msat.as_mut() {
+ *fee_msat -= path.get_path_fees();
+ }
+ }
+ }
+ remove_res
+ }
+
+ fn insert(&mut self, session_priv: [u8; 32], path: &Vec<RouteHop>) -> bool {
+ let insert_res = match self {
+ PendingOutboundPayment::Legacy { session_privs } |
+ PendingOutboundPayment::Retryable { session_privs, .. } => {
+ session_privs.insert(session_priv)
+ }
+ PendingOutboundPayment::Fulfilled { .. } => false
+ };
+ if insert_res {
+ if let PendingOutboundPayment::Retryable { ref mut pending_amt_msat, ref mut pending_fee_msat, .. } = self {
+ let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
+ *pending_amt_msat += path_last_hop.fee_msat;
+ if let Some(fee_msat) = pending_fee_msat.as_mut() {
+ *fee_msat += path.get_path_fees();
+ }
+ }
+ }
+ insert_res
+ }
+
+ fn remaining_parts(&self) -> usize {
+ match self {
+ PendingOutboundPayment::Legacy { session_privs } |
+ PendingOutboundPayment::Retryable { session_privs, .. } |
+ PendingOutboundPayment::Fulfilled { session_privs } => {
+ session_privs.len()
+ }
+ }
+ }
+}
+