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-rw-r--r--src/utils/order_validation_utils.ts66
1 files changed, 66 insertions, 0 deletions
diff --git a/src/utils/order_validation_utils.ts b/src/utils/order_validation_utils.ts
new file mode 100644
index 000000000..05c284ac3
--- /dev/null
+++ b/src/utils/order_validation_utils.ts
@@ -0,0 +1,66 @@
+import {ExchangeContractErrs, SignedOrder} from '../types';
+
+export const orderValidationUtils = {
+ /**
+ * This method does not currently validate the edge-case where the makerToken or takerToken is also the token used
+ * to pay fees (ZRX). It is possible for them to have enough for fees and the transfer but not both.
+ * Handling the edge-cases that arise when this happens would require making sure that the user has sufficient
+ * funds to pay both the fees and the transfer amount. We decided to punt on this for now as the contracts
+ * will throw for these edge-cases.
+ * TODO: Throw errors before calling the smart contract for these edge-cases in order to minimize
+ * the callers gas costs.
+ */
+ async validateFillOrderBalancesAndAllowancesAndThrowIfInvalidAsync(
+ signedOrder: SignedOrder, fillTakerAmount: BigNumber.BigNumber, senderAddress: string, zrxTokenAddress: string,
+ ): Promise<void> {
+
+ const makerBalance = await this._tokenWrapper.getBalanceAsync(signedOrder.makerTokenAddress,
+ signedOrder.maker);
+ const takerBalance = await this._tokenWrapper.getBalanceAsync(signedOrder.takerTokenAddress, senderAddress);
+ const makerAllowance = await this._tokenWrapper.getProxyAllowanceAsync(signedOrder.makerTokenAddress,
+ signedOrder.maker);
+ const takerAllowance = await this._tokenWrapper.getProxyAllowanceAsync(signedOrder.takerTokenAddress,
+ senderAddress);
+
+ // exchangeRate is the price of one maker token denominated in taker tokens
+ const exchangeRate = signedOrder.takerTokenAmount.div(signedOrder.makerTokenAmount);
+ const fillMakerAmountInBaseUnits = fillTakerAmount.div(exchangeRate);
+
+ const isMakerTokenZRX = signedOrder.makerTokenAddress === zrxTokenAddress;
+ const isTakerTokenZRX = signedOrder.takerTokenAddress === zrxTokenAddress;
+
+ if (fillTakerAmount.greaterThan(takerBalance)) {
+ throw new Error(ExchangeContractErrs.InsufficientTakerBalance);
+ }
+ if (fillTakerAmount.greaterThan(takerAllowance)) {
+ throw new Error(ExchangeContractErrs.InsufficientTakerAllowance);
+ }
+ if (fillMakerAmountInBaseUnits.greaterThan(makerBalance)) {
+ throw new Error(ExchangeContractErrs.InsufficientMakerBalance);
+ }
+ if (fillMakerAmountInBaseUnits.greaterThan(makerAllowance)) {
+ throw new Error(ExchangeContractErrs.InsufficientMakerAllowance);
+ }
+
+ const makerFeeBalance = await this._tokenWrapper.getBalanceAsync(zrxTokenAddress,
+ signedOrder.maker);
+ const takerFeeBalance = await this._tokenWrapper.getBalanceAsync(zrxTokenAddress, senderAddress);
+ const makerFeeAllowance = await this._tokenWrapper.getProxyAllowanceAsync(zrxTokenAddress,
+ signedOrder.maker);
+ const takerFeeAllowance = await this._tokenWrapper.getProxyAllowanceAsync(zrxTokenAddress,
+ senderAddress);
+
+ if (signedOrder.takerFee.greaterThan(takerFeeBalance)) {
+ throw new Error(ExchangeContractErrs.InsufficientTakerFeeBalance);
+ }
+ if (signedOrder.takerFee.greaterThan(takerFeeAllowance)) {
+ throw new Error(ExchangeContractErrs.InsufficientTakerFeeAllowance);
+ }
+ if (signedOrder.makerFee.greaterThan(makerFeeBalance)) {
+ throw new Error(ExchangeContractErrs.InsufficientMakerFeeBalance);
+ }
+ if (signedOrder.makerFee.greaterThan(makerFeeAllowance)) {
+ throw new Error(ExchangeContractErrs.InsufficientMakerFeeAllowance);
+ }
+ },
+};