feat(payments): add dust limit (#23)

Author: MohammadNassar1

src/errors.cairo

@@ -1,6 +1,7 @@
 use starknet::ContractAddress;
 
 pub const ADDRESS_ALREADY_ALLOWED: felt252 = 'ADDRESS_ALREADY_ALLOWED';
+pub const INVALID_AMOUNT_BELOW_DUST_LIMIT: felt252 = 'INVALID_AMOUNT_BELOW_DUST_LIMIT';
 pub const INVALID_AMOUNT_RATIO: felt252 = 'INVALID_AMOUNT_RATIO';
 pub const INVALID_AMOUNT_TOO_LARGE: felt252 = 'INVALID_AMOUNT_TOO_LARGE';
 pub const INVALID_DOWNCAST_AFTER_DIVISION: felt252 = 'INVALID_DOWNCAST_AFTER_DIVISION';

src/events.cairo

@@ -1,6 +1,11 @@
 use starknet::ContractAddress;
 use starkware_utils::signature::stark::HashType;
 
+#[derive(Debug, Drop, PartialEq, starknet::Event)]
+pub struct DustLimitSet {
+    pub dust_limit: u128,
+}
+
 #[derive(Debug, Drop, PartialEq, starknet::Event)]
 pub struct FeeSet {
     pub fee: u128,

src/interface.cairo

@@ -26,11 +26,13 @@ pub trait IPayments<TContractState> {
 
     // Setters:
 
+    fn set_dust_limit(ref self: TContractState, dust_limit: u128);
     fn set_fee(ref self: TContractState, fee: u128);
     fn set_fee_recipient(ref self: TContractState, recipient: ContractAddress);
 
     // Getters:
 
+    fn get_dust_limit(self: @TContractState) -> u128;
     fn get_fee_limit(self: @TContractState) -> u128;
     fn get_fee(self: @TContractState) -> u128;
     fn get_fee_recipient(self: @TContractState) -> ContractAddress;

src/payments.cairo

@@ -21,15 +21,15 @@ pub mod payments {
     use starkware_utils::signature::stark::{HashType, Signature};
     use starkware_utils::time::time::Time;
     use crate::errors::{
-        ADDRESS_ALREADY_ALLOWED, INVALID_AMOUNT_RATIO, INVALID_AMOUNT_TOO_LARGE,
-        INVALID_DOWNCAST_AFTER_DIVISION, INVALID_HIGH_FEE, INVALID_HIGH_FEE_LIMIT,
-        INVALID_TOKEN_PAIR, INVALID_TRADE_SAME_USER, INVALID_ZERO_ADDRESS, INVALID_ZERO_AMOUNT,
-        INVALID_ZERO_TOKEN, ORDER_EXPIRED, TOKEN_ALREADY_REGISTERED, TOKEN_NOT_REGISTERED,
-        UNALLOWED_ADDRESS, UNAPPROVED_COUNTERPARTY, transfer_failed_error,
+        ADDRESS_ALREADY_ALLOWED, INVALID_AMOUNT_BELOW_DUST_LIMIT, INVALID_AMOUNT_RATIO,
+        INVALID_AMOUNT_TOO_LARGE, INVALID_DOWNCAST_AFTER_DIVISION, INVALID_HIGH_FEE,
+        INVALID_HIGH_FEE_LIMIT, INVALID_TOKEN_PAIR, INVALID_TRADE_SAME_USER, INVALID_ZERO_ADDRESS,
+        INVALID_ZERO_AMOUNT, INVALID_ZERO_TOKEN, ORDER_EXPIRED, TOKEN_ALREADY_REGISTERED,
+        TOKEN_NOT_REGISTERED, UNALLOWED_ADDRESS, UNAPPROVED_COUNTERPARTY, transfer_failed_error,
     };
     use crate::events::{
-        AddressAllowed, AddressDisallowed, FeeRecipientSet, FeeSet, OrderCanceled, TokenRegistered,
-        TokenRemoved, TradeExecuted,
+        AddressAllowed, AddressDisallowed, DustLimitSet, FeeRecipientSet, FeeSet, OrderCanceled,
+        TokenRegistered, TokenRemoved, TradeExecuted,
     };
     use crate::interface::IPayments;
     use crate::order::Order;
@@ -82,6 +82,7 @@ pub mod payments {
         #[substorage(v0)]
         src5: SRC5Component::Storage,
         // --- Payment ---
+        dust_limit: u128,
         fee_limit: u128,
         fee_recipient: ContractAddress,
         fee: u128,
@@ -114,6 +115,7 @@ pub mod payments {
         AddressDisallowed: AddressDisallowed,
         TradeExecuted: TradeExecuted,
         OrderCanceled: OrderCanceled,
+        DustLimitSet: DustLimitSet,
     }
 
 
@@ -122,13 +124,15 @@ pub mod payments {
         ref self: ContractState,
         governance_admin: ContractAddress,
         upgrade_delay: u64,
+        dust_limit: u128,
         fee_limit: u128,
         fee_recipient: ContractAddress,
         fee: u128,
     ) {
         self.roles.initialize(:governance_admin);
         self.replaceability.initialize(:upgrade_delay);
 
+        self._set_dust_limit(dust_limit);
         assert(fee_limit <= MAX_BASIS_POINTS.into(), INVALID_HIGH_FEE_LIMIT);
         self.fee_limit.write(fee_limit);
         self._set_fee_recipient(recipient: fee_recipient);
@@ -329,6 +333,11 @@ pub mod payments {
 
         // Setters:
 
+        fn set_dust_limit(ref self: ContractState, dust_limit: u128) {
+            self.roles.only_operator();
+
+            self._set_dust_limit(:dust_limit);
+        }
         fn set_fee(ref self: ContractState, fee: u128) {
             self.roles.only_operator();
 
@@ -342,6 +351,10 @@ pub mod payments {
 
         // Getters:
 
+        fn get_dust_limit(self: @ContractState) -> u128 {
+            self.dust_limit.read()
+        }
+
         fn get_fee_limit(self: @ContractState) -> u128 {
             self.fee_limit.read()
         }
@@ -368,6 +381,14 @@ pub mod payments {
     // Internal methods
     #[generate_trait]
     pub impl ImplInternalPayments of InternalPaymentsTrait {
+        fn _set_dust_limit(ref self: ContractState, dust_limit: u128) {
+            assert(dust_limit.is_non_zero(), INVALID_ZERO_AMOUNT);
+            self.dust_limit.write(dust_limit);
+
+            // Emit an event.
+            self.emit(DustLimitSet { dust_limit });
+        }
+
         fn _set_fee(ref self: ContractState, fee: u128) {
             assert(fee <= self.fee_limit.read(), INVALID_HIGH_FEE);
             self.fee.write(fee);
@@ -476,8 +497,9 @@ pub mod payments {
                 INVALID_AMOUNT_RATIO,
             );
 
-            assert(order_a_actual_sell_amount.is_non_zero(), INVALID_ZERO_AMOUNT);
-            assert(order_a_actual_buy_amount.is_non_zero(), INVALID_ZERO_AMOUNT);
+            let dust_limit = self.dust_limit.read();
+            assert(order_a_actual_sell_amount >= dust_limit, INVALID_AMOUNT_BELOW_DUST_LIMIT);
+            assert(order_a_actual_buy_amount >= dust_limit, INVALID_AMOUNT_BELOW_DUST_LIMIT);
 
             // Validate approved counterparties.
             assert(