gmsol_model/
bank.rs

1use std::borrow::Borrow;
2
3use num_traits::{CheckedSub, Zero};
4
5/// A bank of tokens.
6pub trait Bank<K> {
7    /// Number type.
8    type Num;
9
10    /// Record transferred in amount by token.
11    fn record_transferred_in_by_token<Q: Borrow<K> + ?Sized>(
12        &mut self,
13        token: &Q,
14        amount: &Self::Num,
15    ) -> crate::Result<()>;
16
17    /// Record transferred out amount by token.
18    fn record_transferred_out_by_token<Q: Borrow<K> + ?Sized>(
19        &mut self,
20        token: &Q,
21        amount: &Self::Num,
22    ) -> crate::Result<()>;
23
24    /// Get the balance of the given token.
25    fn balance<Q: Borrow<K> + ?Sized>(&self, token: &Q) -> crate::Result<Self::Num>;
26
27    /// Get the balance of the given token excluding `excluded` amount.
28    fn balance_excluding<Q: Borrow<K> + ?Sized>(
29        &self,
30        token: &Q,
31        excluded: &Self::Num,
32    ) -> crate::Result<Self::Num>
33    where
34        Self::Num: CheckedSub + Zero,
35    {
36        let balance = self.balance(token)?;
37        if excluded.is_zero() {
38            Ok(balance)
39        } else {
40            balance
41                .checked_sub(excluded)
42                .ok_or(crate::Error::Computation(
43                    "underflow when excluding amount of balance",
44                ))
45        }
46    }
47}
gmsol_model/bank.rs

gmsol_model/
bank.rs
