Fix refund calculation: we need to use different gas limits for each ERC tokens & bump lib version to 1.2.0

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@tornado/tornado-oracles",
-  "version": "1.1.0",
+  "version": "1.2.0",
   "description": "Gas oracle for Tornado-specific transactions",
   "main": "./lib/index.js",
   "types": "./lib/index.d.ts",

src/config.ts

@@ -11,6 +11,14 @@ export enum ChainId {
   AVAX = 43114,
 }
 
+export enum InstanceTokenSymbol {
+  DAI = 'dai',
+  cDAI = 'cdai',
+  WBTC = 'wbtc',
+  USDT = 'usdt',
+  USDC = 'usdc',
+}
+
 export type GasPricesConfig = {
   [chainId in ChainId]: LegacyGasPrices;
 };
@@ -81,6 +89,18 @@ export const defaultWithdrawalGasLimit: GasLimitConfig = {
   [ChainId.XDAI]: 390000,
 };
 
+type InstanceTokenGasLimitConfig = {
+  [tokenSymbol in InstanceTokenSymbol]: number;
+};
+
+export const defaultInstanceTokensGasLimit: InstanceTokenGasLimitConfig = {
+  [InstanceTokenSymbol.DAI]: 55000,
+  [InstanceTokenSymbol.cDAI]: 425000,
+  [InstanceTokenSymbol.WBTC]: 85000,
+  [InstanceTokenSymbol.USDT]: 100000,
+  [InstanceTokenSymbol.USDC]: 80000,
+};
+
 export const optimismL1FeeOracleAddress = '0x420000000000000000000000000000000000000F';
 export const offchainOracleAddress = '0x07D91f5fb9Bf7798734C3f606dB065549F6893bb';
 export const multiCallAddress = '0xda3c19c6fe954576707fa24695efb830d9cca1ca';

src/feeOracle.ts

@@ -3,7 +3,7 @@ import { BigNumber, BigNumberish, ethers } from 'ethers';
 import { parseUnits } from 'ethers/lib/utils';
 import { TransactionData, TxType, ITornadoFeeOracle, LegacyGasPriceKey, GasPriceParams } from './types';
 import { JsonRpcProvider } from '@ethersproject/providers';
-import { ChainId, defaultGasPrices } from './config';
+import { ChainId, defaultGasPrices, defaultInstanceTokensGasLimit, InstanceTokenSymbol } from './config';
 import { bump, calculateGasPriceInWei, convertETHToToken, fromGweiToWeiHex, serializeTx } from './utils';
 import { getOptimismL1FeeOracle } from './contracts/factories';
 import { AvailableTokenSymbols } from '@tornado/tornado-config';
@@ -102,28 +102,29 @@ export abstract class TornadoFeeOracle implements ITornadoFeeOracle {
    * and if the relayer pays a commission and the transfer of tokens fails, this commission will remain to the relayer.
    *
    * Refund needed that recipient can use tokens after withdrawal (covers gas fee for send/swap)
-   * @param {TransactionData} [tx] Transaction data (object in web3 / ethers format)
+   * @param {InstanceTokenSymbol} tokenSymbol Withdrawal token (currency) symbol - for example, 'dai'
    * @returns {Promise<string>} Refund amount in WEI (hexed number)
    */
-  async calculateRefundInETH(tx?: TransactionData): Promise<string> {
+  async calculateRefundInETH(tokenSymbol: InstanceTokenSymbol): Promise<string> {
     // In Tornado we need to calculate refund only on user side, relayer get refund value in proof
-    const gas = await this.getGas(tx, 'user_withdrawal');
+    const gasPrice = await this.getGasPrice();
-    return BigNumber.from(gas).mul(2).toHexString();
+    const gasLimit = defaultInstanceTokensGasLimit[tokenSymbol];
+    return BigNumber.from(gasPrice).mul(gasLimit).mul(2).toHexString();
   }
 
   /**
    * Get refund amount on ETH or Goerli in non-native token
    * @param {BigNumberish} tokenPriceInEth Token price in WEI in native currency
    * @param {string | number} tokenDecimals Token (currency) decimals
-   * @param {TransactionData} [tx] Transaction data (object in web3 / ethers format)
+   * @param {InstanceTokenSymbol} tokenSymbol Withdrawal token (currency) symbol - for example, 'dai'
    * @returns {Promise<string>} Refund amount in WEI in selected token (hexed number)
    */
   async calculateRefundInToken(
     tokenPriceInEth: BigNumberish,
     tokenDecimals: string | number,
-    tx?: TransactionData,
+    tokenSymbol: InstanceTokenSymbol,
   ): Promise<string> {
-    const refundInEth = await this.calculateRefundInETH(tx);
+    const refundInEth = await this.calculateRefundInETH(tokenSymbol);
     return convertETHToToken(refundInEth, tokenDecimals, tokenPriceInEth).toHexString();
   }
 
@@ -148,7 +149,7 @@ export abstract class TornadoFeeOracle implements ITornadoFeeOracle {
     currency: AvailableTokenSymbols | Uppercase<AvailableTokenSymbols>,
     amount: string | number,
     decimals: string | number,
-    refund: BigNumberish = 0,
+    refundInEth: BigNumberish = 0,
     tokenPriceInEth?: BigNumberish,
   ): Promise<string> {
     const gasCosts = BigNumber.from(await this.getGas(tx, type));
@@ -163,7 +164,7 @@ export abstract class TornadoFeeOracle implements ITornadoFeeOracle {
         return '0';
       }
 
-      const feeInEth = gasCosts.add(refund);
+      const feeInEth = gasCosts.add(refundInEth);
       return convertETHToToken(feeInEth, decimals, tokenPriceInEth).add(relayerFee).toHexString();
     }
 

src/types.ts

@@ -1,6 +1,7 @@
 import { BigNumberish, BytesLike } from 'ethers';
 import { GasPriceKey, GetTxGasParamsRes } from '@tornado/gas-price-oracle/lib/services';
 import { AvailableTokenSymbols } from '@tornado/tornado-config';
+import { InstanceTokenSymbol } from './config';
 
 export type LegacyGasPriceKey = GasPriceKey;
 export type GasPriceParams = GetTxGasParamsRes;
@@ -36,11 +37,11 @@ export interface ITornadoFeeOracle {
   getGasPrice: (type?: TxType, speed?: LegacyGasPriceKey, bumpPercent?: number) => Promise<string>;
   getGasLimit: (tx?: TransactionData, type?: TxType, bumpPercent?: number) => Promise<number>;
   fetchL1OptimismFee: (tx?: TransactionData) => Promise<string>;
-  calculateRefundInETH: (tx?: TransactionData) => Promise<string>;
+  calculateRefundInETH: (tokenSymbol: InstanceTokenSymbol) => Promise<string>;
   calculateRefundInToken: (
     tokenPriceInEth: BigNumberish,
     tokenDecimals: string | number,
-    tx?: TransactionData,
+    tokenSymbol: InstanceTokenSymbol,
   ) => Promise<string>;
   calculateWithdrawalFeeViaRelayer: (
     type: TxType,