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import * as _ from 'lodash';
import {Web3Wrapper} from '../web3_wrapper';
import {
ECSignature,
ExchangeContract,
ExchangeContractErrCodes,
ExchangeContractErrs,
OrderValues,
OrderAddresses,
SignedOrder,
ContractEvent,
ContractResponse,
} from '../types';
import {assert} from '../utils/assert';
import {ContractWrapper} from './contract_wrapper';
import * as ExchangeArtifacts from '../artifacts/Exchange.json';
import {ecSignatureSchema} from '../schemas/ec_signature_schema';
import {signedOrderSchema} from '../schemas/order_schemas';
import {SchemaValidator} from '../utils/schema_validator';
import {constants} from '../utils/constants';
import {TokenWrapper} from './token_wrapper';
export class ExchangeWrapper extends ContractWrapper {
private exchangeContractErrCodesToMsg = {
[ExchangeContractErrCodes.ERROR_FILL_EXPIRED]: ExchangeContractErrs.ORDER_FILL_EXPIRED,
[ExchangeContractErrCodes.ERROR_CANCEL_EXPIRED]: ExchangeContractErrs.ORDER_FILL_EXPIRED,
[ExchangeContractErrCodes.ERROR_FILL_NO_VALUE]: ExchangeContractErrs.ORDER_REMAINING_FILL_AMOUNT_ZERO,
[ExchangeContractErrCodes.ERROR_CANCEL_NO_VALUE]: ExchangeContractErrs.ORDER_REMAINING_FILL_AMOUNT_ZERO,
[ExchangeContractErrCodes.ERROR_FILL_TRUNCATION]: ExchangeContractErrs.ORDER_FILL_ROUNDING_ERROR,
[ExchangeContractErrCodes.ERROR_FILL_BALANCE_ALLOWANCE]: ExchangeContractErrs.FILL_BALANCE_ALLOWANCE_ERROR,
};
private exchangeContractIfExists?: ExchangeContract;
private tokenWrapper: TokenWrapper;
constructor(web3Wrapper: Web3Wrapper, tokenWrapper: TokenWrapper) {
super(web3Wrapper);
this.tokenWrapper = tokenWrapper;
}
public invalidateContractInstance(): void {
delete this.exchangeContractIfExists;
}
public async isValidSignatureAsync(dataHex: string, ecSignature: ECSignature,
signerAddressHex: string): Promise<boolean> {
assert.isHexString('dataHex', dataHex);
assert.doesConformToSchema('ecSignature', ecSignature, ecSignatureSchema);
assert.isETHAddressHex('signerAddressHex', signerAddressHex);
const senderAddress = await this.web3Wrapper.getSenderAddressOrThrowAsync();
const exchangeInstance = await this.getExchangeContractAsync();
const isValidSignature = await exchangeInstance.isValidSignature.call(
signerAddressHex,
dataHex,
ecSignature.v,
ecSignature.r,
ecSignature.s,
{
from: senderAddress,
},
);
return isValidSignature;
}
/**
* Fills a signed order with a fillAmount denominated in baseUnits of the taker token.
* Since the order in which transactions are included in the next block is indeterminate, race-conditions
* could arise where a users balance or allowance changes before the fillOrder executes. Because of this,
* we allow you to specify `shouldCheckTransfer`. If true, the smart contract will not throw if while
* executing, the parties do not have sufficient balances/allowances, preserving gas costs. Setting it to
* false forgoes this check and causes the smart contract to throw instead.
*/
public async fillOrderAsync(signedOrder: SignedOrder, fillTakerAmount: BigNumber.BigNumber,
shouldCheckTransfer: boolean): Promise<void> {
assert.doesConformToSchema('signedOrder',
SchemaValidator.convertToJSONSchemaCompatibleObject(signedOrder as object),
signedOrderSchema);
assert.isBigNumber('fillTakerAmount', fillTakerAmount);
assert.isBoolean('shouldCheckTransfer', shouldCheckTransfer);
const senderAddress = await this.web3Wrapper.getSenderAddressOrThrowAsync();
const exchangeInstance = await this.getExchangeContractAsync();
await this.validateFillOrderAndThrowIfInvalidAsync(signedOrder, fillTakerAmount, senderAddress);
const orderAddresses: OrderAddresses = [
signedOrder.maker,
signedOrder.taker,
signedOrder.makerTokenAddress,
signedOrder.takerTokenAddress,
signedOrder.feeRecipient,
];
const orderValues: OrderValues = [
signedOrder.makerTokenAmount,
signedOrder.takerTokenAmount,
signedOrder.makerFee,
signedOrder.takerFee,
signedOrder.expirationUnixTimestampSec,
signedOrder.salt,
];
const gas = await exchangeInstance.fill.estimateGas(
orderAddresses,
orderValues,
fillTakerAmount,
shouldCheckTransfer,
signedOrder.ecSignature.v,
signedOrder.ecSignature.r,
signedOrder.ecSignature.s,
{
from: senderAddress,
},
);
const response: ContractResponse = await exchangeInstance.fill(
orderAddresses,
orderValues,
fillTakerAmount,
shouldCheckTransfer,
signedOrder.ecSignature.v,
signedOrder.ecSignature.r,
signedOrder.ecSignature.s,
{
from: senderAddress,
gas,
},
);
this.throwErrorLogsAsErrors(response.logs);
}
private async validateFillOrderAndThrowIfInvalidAsync(signedOrder: SignedOrder,
fillTakerAmount: BigNumber.BigNumber,
senderAddress: string): Promise<void> {
if (fillTakerAmount.eq(0)) {
throw new Error(ExchangeContractErrs.ORDER_REMAINING_FILL_AMOUNT_ZERO);
}
if (signedOrder.taker !== constants.NULL_ADDRESS && signedOrder.taker !== senderAddress) {
throw new Error(ExchangeContractErrs.TRANSACTION_SENDER_IS_NOT_FILL_ORDER_TAKER);
}
const currentUnixTimestampSec = Date.now() / 1000;
if (signedOrder.expirationUnixTimestampSec.lessThan(currentUnixTimestampSec)) {
throw new Error(ExchangeContractErrs.ORDER_FILL_EXPIRED);
}
const zrxTokenAddress = await this.getZRXTokenAddressAsync();
await this.validateFillOrderBalancesAndAllowancesAndThrowIfInvalidAsync(signedOrder, fillTakerAmount,
senderAddress, zrxTokenAddress);
const wouldRoundingErrorOccur = await this.isRoundingErrorAsync(
signedOrder.takerTokenAmount, fillTakerAmount, signedOrder.makerTokenAmount,
);
if (wouldRoundingErrorOccur) {
throw new Error(ExchangeContractErrs.ORDER_FILL_ROUNDING_ERROR);
}
}
/**
* 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
* TODO: in order to minimize the callers gas costs.
*/
private 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);
if (fillTakerAmount.greaterThan(takerBalance)) {
throw new Error(ExchangeContractErrs.INSUFFICIENT_TAKER_BALANCE);
}
if (fillTakerAmount.greaterThan(takerAllowance)) {
throw new Error(ExchangeContractErrs.INSUFFICIENT_TAKER_ALLOWANCE);
}
if (fillMakerAmountInBaseUnits.greaterThan(makerBalance)) {
throw new Error(ExchangeContractErrs.INSUFFICIENT_MAKER_BALANCE);
}
if (fillMakerAmountInBaseUnits.greaterThan(makerAllowance)) {
throw new Error(ExchangeContractErrs.INSUFFICIENT_MAKER_ALLOWANCE);
}
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.INSUFFICIENT_TAKER_FEE_BALANCE);
}
if (signedOrder.takerFee.greaterThan(takerFeeAllowance)) {
throw new Error(ExchangeContractErrs.INSUFFICIENT_TAKER_FEE_ALLOWANCE);
}
if (signedOrder.makerFee.greaterThan(makerFeeBalance)) {
throw new Error(ExchangeContractErrs.INSUFFICIENT_MAKER_FEE_BALANCE);
}
if (signedOrder.makerFee.greaterThan(makerFeeAllowance)) {
throw new Error(ExchangeContractErrs.INSUFFICIENT_MAKER_FEE_ALLOWANCE);
}
}
private throwErrorLogsAsErrors(logs: ContractEvent[]): void {
const errEvent = _.find(logs, {event: 'LogError'});
if (!_.isUndefined(errEvent)) {
const errCode = errEvent.args.errorId.toNumber();
const errMessage = this.exchangeContractErrCodesToMsg[errCode];
throw new Error(errMessage);
}
}
private async isRoundingErrorAsync(takerTokenAmount: BigNumber.BigNumber,
fillTakerAmount: BigNumber.BigNumber,
makerTokenAmount: BigNumber.BigNumber): Promise<boolean> {
const exchangeInstance = await this.getExchangeContractAsync();
const senderAddress = await this.web3Wrapper.getSenderAddressOrThrowAsync();
const isRoundingError = await exchangeInstance.isRoundingError.call(
takerTokenAmount, fillTakerAmount, makerTokenAmount, {
from: senderAddress,
},
);
return isRoundingError;
}
private async getExchangeContractAsync(): Promise<ExchangeContract> {
if (!_.isUndefined(this.exchangeContractIfExists)) {
return this.exchangeContractIfExists;
}
const contractInstance = await this.instantiateContractIfExistsAsync((ExchangeArtifacts as any));
this.exchangeContractIfExists = contractInstance as ExchangeContract;
return this.exchangeContractIfExists;
}
private async getZRXTokenAddressAsync(): Promise<string> {
const exchangeInstance = await this.getExchangeContractAsync();
return exchangeInstance.ZRX.call();
}
}
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