89 lines
4.5 KiB
TypeScript
89 lines
4.5 KiB
TypeScript
import * as _ from 'lodash';
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import BigNumber from 'bignumber.js';
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import {ExchangeContractErrs, TradeSide, TransferType, BlockParamLiteral} from '../types';
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import {TokenWrapper} from '../contract_wrappers/token_wrapper';
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import {BalanceAndProxyAllowanceLazyStore} from '../stores/balance_proxy_allowance_lazy_store';
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enum FailureReason {
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Balance = 'balance',
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ProxyAllowance = 'proxyAllowance',
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}
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const ERR_MSG_MAPPING = {
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[FailureReason.Balance]: {
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[TradeSide.Maker]: {
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[TransferType.Trade]: ExchangeContractErrs.InsufficientMakerBalance,
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[TransferType.Fee]: ExchangeContractErrs.InsufficientMakerFeeBalance,
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},
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[TradeSide.Taker]: {
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[TransferType.Trade]: ExchangeContractErrs.InsufficientTakerBalance,
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[TransferType.Fee]: ExchangeContractErrs.InsufficientTakerFeeBalance,
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},
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},
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[FailureReason.ProxyAllowance]: {
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[TradeSide.Maker]: {
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[TransferType.Trade]: ExchangeContractErrs.InsufficientMakerAllowance,
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[TransferType.Fee]: ExchangeContractErrs.InsufficientMakerFeeAllowance,
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},
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[TradeSide.Taker]: {
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[TransferType.Trade]: ExchangeContractErrs.InsufficientTakerAllowance,
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[TransferType.Fee]: ExchangeContractErrs.InsufficientTakerFeeAllowance,
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},
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},
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};
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export class ExchangeTransferSimulator {
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private store: BalanceAndProxyAllowanceLazyStore;
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private UNLIMITED_ALLOWANCE_IN_BASE_UNITS: BigNumber;
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constructor(token: TokenWrapper) {
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this.store = new BalanceAndProxyAllowanceLazyStore(token);
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this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS = token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS;
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}
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/**
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* Simulates transferFrom call performed by a proxy
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* @param tokenAddress Address of the token to be transferred
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* @param from Owner of the transferred tokens
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* @param to Recipient of the transferred tokens
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* @param amountInBaseUnits The amount of tokens being transferred
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* @param tradeSide Is Maker/Taker transferring
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* @param transferType Is it a fee payment or a value transfer
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*/
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public async transferFromAsync(tokenAddress: string, from: string, to: string,
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amountInBaseUnits: BigNumber, tradeSide: TradeSide,
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transferType: TransferType): Promise<void> {
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const balance = await this.store.getBalanceAsync(tokenAddress, from);
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const proxyAllowance = await this.store.getProxyAllowanceAsync(tokenAddress, from);
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if (proxyAllowance.lessThan(amountInBaseUnits)) {
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this.throwValidationError(FailureReason.ProxyAllowance, tradeSide, transferType);
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}
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if (balance.lessThan(amountInBaseUnits)) {
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this.throwValidationError(FailureReason.Balance, tradeSide, transferType);
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}
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await this.decreaseProxyAllowanceAsync(tokenAddress, from, amountInBaseUnits);
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await this.decreaseBalanceAsync(tokenAddress, from, amountInBaseUnits);
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await this.increaseBalanceAsync(tokenAddress, to, amountInBaseUnits);
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}
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private async decreaseProxyAllowanceAsync(tokenAddress: string, userAddress: string,
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amountInBaseUnits: BigNumber): Promise<void> {
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const proxyAllowance = await this.store.getProxyAllowanceAsync(tokenAddress, userAddress);
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if (!proxyAllowance.eq(this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS)) {
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this.store.setProxyAllowance(tokenAddress, userAddress, proxyAllowance.minus(amountInBaseUnits));
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}
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}
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private async increaseBalanceAsync(tokenAddress: string, userAddress: string,
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amountInBaseUnits: BigNumber): Promise<void> {
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const balance = await this.store.getBalanceAsync(tokenAddress, userAddress);
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this.store.setBalance(tokenAddress, userAddress, balance.plus(amountInBaseUnits));
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}
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private async decreaseBalanceAsync(tokenAddress: string, userAddress: string,
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amountInBaseUnits: BigNumber): Promise<void> {
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const balance = await this.store.getBalanceAsync(tokenAddress, userAddress);
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this.store.setBalance(tokenAddress, userAddress, balance.minus(amountInBaseUnits));
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}
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private throwValidationError(failureReason: FailureReason, tradeSide: TradeSide,
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transferType: TransferType): Promise<never> {
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const errMsg = ERR_MSG_MAPPING[failureReason][tradeSide][transferType];
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throw new Error(errMsg);
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}
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}
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