112 lines
4.9 KiB
TypeScript
112 lines
4.9 KiB
TypeScript
import { ExchangeContractErrs } from '@0x/types';
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import { BigNumber } from '@0x/utils';
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import { AbstractBalanceAndProxyAllowanceLazyStore } from '../abstract/abstract_balance_and_proxy_allowance_lazy_store';
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import { TradeSide, TransferType } from '../types';
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import { constants } from '../utils/constants';
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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 readonly _store: AbstractBalanceAndProxyAllowanceLazyStore;
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private static _throwValidationError(
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failureReason: FailureReason,
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tradeSide: TradeSide,
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transferType: TransferType,
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): 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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constructor(store: AbstractBalanceAndProxyAllowanceLazyStore) {
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this._store = store;
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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(
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tokenAddress: string,
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from: string,
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to: string,
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amountInBaseUnits: BigNumber,
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tradeSide: TradeSide,
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transferType: TransferType,
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): Promise<void> {
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// HACK: When simulating an open order (e.g taker is NULL_ADDRESS), we don't want to adjust balances/
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// allowances for the taker. We do however, want to increase the balance of the maker since the maker
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// might be relying on those funds to fill subsequent orders or pay the order's fees.
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if (from === constants.NULL_ADDRESS && tradeSide === TradeSide.Taker) {
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await this._increaseBalanceAsync(tokenAddress, to, amountInBaseUnits);
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return;
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}
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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.isLessThan(amountInBaseUnits)) {
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ExchangeTransferSimulator._throwValidationError(FailureReason.ProxyAllowance, tradeSide, transferType);
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}
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if (balance.isLessThan(amountInBaseUnits)) {
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ExchangeTransferSimulator._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(
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tokenAddress: string,
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userAddress: string,
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amountInBaseUnits: BigNumber,
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): Promise<void> {
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const proxyAllowance = await this._store.getProxyAllowanceAsync(tokenAddress, userAddress);
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if (!proxyAllowance.eq(constants.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(
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tokenAddress: string,
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userAddress: string,
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amountInBaseUnits: BigNumber,
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): 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(
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tokenAddress: string,
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userAddress: string,
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amountInBaseUnits: BigNumber,
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): 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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}
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