+pub mod router;
+pub mod scorer;
+
+use routing::network_graph::NodeId;
+use routing::router::RouteHop;
+
+use core::cell::{RefCell, RefMut};
+use core::ops::DerefMut;
+use sync::{Mutex, MutexGuard};
+
+/// An interface used to score payment channels for path finding.
+///
+/// Scoring is in terms of fees willing to be paid in order to avoid routing through a channel.
+pub trait Score {
+ /// Returns the fee in msats willing to be paid to avoid routing through the given channel
+ /// in the direction from `source` to `target`.
+ fn channel_penalty_msat(&self, short_channel_id: u64, source: &NodeId, target: &NodeId) -> u64;
+
+ /// Handles updating channel penalties after failing to route through a channel.
+ fn payment_path_failed(&mut self, path: &[&RouteHop], short_channel_id: u64);
+}
+
+/// A scorer that is accessed under a lock.
+///
+/// Needed so that calls to [`Score::channel_penalty_msat`] in [`find_route`] can be made while
+/// having shared ownership of a scorer but without requiring internal locking in [`Score`]
+/// implementations. Internal locking would be detrimental to route finding performance and could
+/// result in [`Score::channel_penalty_msat`] returning a different value for the same channel.
+///
+/// [`find_route`]: crate::routing::router::find_route
+pub trait LockableScore<'a> {
+ /// The locked [`Score`] type.
+ type Locked: 'a + Score;
+
+ /// Returns the locked scorer.
+ fn lock(&'a self) -> Self::Locked;
+}
+
+impl<'a, T: 'a + Score> LockableScore<'a> for Mutex<T> {
+ type Locked = MutexGuard<'a, T>;
+
+ fn lock(&'a self) -> MutexGuard<'a, T> {
+ Mutex::lock(self).unwrap()
+ }
+}
+
+impl<'a, T: 'a + Score> LockableScore<'a> for RefCell<T> {
+ type Locked = RefMut<'a, T>;
+
+ fn lock(&'a self) -> RefMut<'a, T> {
+ self.borrow_mut()
+ }
+}
+
+impl<S: Score, T: DerefMut<Target=S>> Score for T {
+ fn channel_penalty_msat(&self, short_channel_id: u64, source: &NodeId, target: &NodeId) -> u64 {
+ self.deref().channel_penalty_msat(short_channel_id, source, target)
+ }
+
+ fn payment_path_failed(&mut self, path: &[&RouteHop], short_channel_id: u64) {
+ self.deref_mut().payment_path_failed(path, short_channel_id)
+ }
+}