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import * as _ from 'lodash';
import {ExchangeContractErrs, TradeSide, TransferType} from '../types';
import {TokenWrapper} from '../contract_wrappers/token_wrapper';
enum FailureReason {
Balance = 'balance',
ProxyAllowance = 'proxyAllowance',
}
const ERR_MSG_MAPPING = {
[FailureReason.Balance]: {
[TradeSide.Maker]: {
[TransferType.Trade]: ExchangeContractErrs.InsufficientMakerBalance,
[TransferType.Fee]: ExchangeContractErrs.InsufficientMakerFeeBalance,
},
[TradeSide.Taker]: {
[TransferType.Trade]: ExchangeContractErrs.InsufficientTakerBalance,
[TransferType.Fee]: ExchangeContractErrs.InsufficientTakerFeeBalance,
},
},
[FailureReason.ProxyAllowance]: {
[TradeSide.Maker]: {
[TransferType.Trade]: ExchangeContractErrs.InsufficientMakerAllowance,
[TransferType.Fee]: ExchangeContractErrs.InsufficientMakerFeeAllowance,
},
[TradeSide.Taker]: {
[TransferType.Trade]: ExchangeContractErrs.InsufficientTakerAllowance,
[TransferType.Fee]: ExchangeContractErrs.InsufficientTakerFeeAllowance,
},
},
};
/**
* Copy on read store for balances/proxyAllowances of tokens/accounts touched in trades
*/
export class BalanceAndProxyAllowanceLazyStore {
protected _token: TokenWrapper;
private _balance: {
[tokenAddress: string]: {
[userAddress: string]: BigNumber.BigNumber,
},
};
private _proxyAllowance: {
[tokenAddress: string]: {
[userAddress: string]: BigNumber.BigNumber,
},
};
constructor(token: TokenWrapper) {
this._token = token;
this._balance = {};
this._proxyAllowance = {};
}
protected async getBalanceAsync(tokenAddress: string, userAddress: string): Promise<BigNumber.BigNumber> {
if (_.isUndefined(this._balance[tokenAddress]) || _.isUndefined(this._balance[tokenAddress][userAddress])) {
const balance = await this._token.getBalanceAsync(tokenAddress, userAddress);
this.setBalance(tokenAddress, userAddress, balance);
}
const cachedBalance = this._balance[tokenAddress][userAddress];
return cachedBalance;
}
protected setBalance(tokenAddress: string, userAddress: string, balance: BigNumber.BigNumber): void {
if (_.isUndefined(this._balance[tokenAddress])) {
this._balance[tokenAddress] = {};
}
this._balance[tokenAddress][userAddress] = balance;
}
protected async getProxyAllowanceAsync(tokenAddress: string, userAddress: string): Promise<BigNumber.BigNumber> {
if (_.isUndefined(this._proxyAllowance[tokenAddress]) ||
_.isUndefined(this._proxyAllowance[tokenAddress][userAddress])) {
const proxyAllowance = await this._token.getProxyAllowanceAsync(tokenAddress, userAddress);
this.setProxyAllowance(tokenAddress, userAddress, proxyAllowance);
}
const cachedProxyAllowance = this._proxyAllowance[tokenAddress][userAddress];
return cachedProxyAllowance;
}
protected setProxyAllowance(tokenAddress: string, userAddress: string, proxyAllowance: BigNumber.BigNumber): void {
if (_.isUndefined(this._proxyAllowance[tokenAddress])) {
this._proxyAllowance[tokenAddress] = {};
}
this._proxyAllowance[tokenAddress][userAddress] = proxyAllowance;
}
}
export class ExchangeTransferSimulator extends BalanceAndProxyAllowanceLazyStore {
constructor(token: TokenWrapper) {
super(token);
}
/**
* Simulates transferFrom call performed by a proxy
* @param tokenAddress Address of a token to be transfered
* @param from Owner of the transfered tokens
* @param to Recipient of the transfered tokens
* @param amountInBaseUnits The amount of tokens being transfered
* @param tradeSide Is Maker/Taker transferring
* @param transferType Is it a fee payment or a value transfer
*/
public async transferFromAsync(tokenAddress: string, from: string, to: string,
amountInBaseUnits: BigNumber.BigNumber, tradeSide: TradeSide,
transferType: TransferType): Promise<void> {
const balance = await this.getBalanceAsync(tokenAddress, from);
const proxyAllowance = await this.getProxyAllowanceAsync(tokenAddress, from);
if (balance.lessThan(amountInBaseUnits)) {
this.throwValidationError(FailureReason.Balance, tradeSide, transferType);
}
if (proxyAllowance.lessThan(amountInBaseUnits)) {
this.throwValidationError(FailureReason.ProxyAllowance, tradeSide, transferType);
}
await this.decreaseProxyAllowanceAsync(tokenAddress, from, amountInBaseUnits);
await this.decreaseBalanceAsync(tokenAddress, from, amountInBaseUnits);
if (!_.isUndefined(to)) {
await this.increaseBalanceAsync(tokenAddress, to, amountInBaseUnits);
}
}
private async decreaseProxyAllowanceAsync(tokenAddress: string, userAddress: string,
amountInBaseUnits: BigNumber.BigNumber): Promise<void> {
const proxyAllowance = await this.getProxyAllowanceAsync(tokenAddress, userAddress);
if (!proxyAllowance.eq(this._token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS)) {
this.setProxyAllowance(tokenAddress, userAddress, proxyAllowance.minus(amountInBaseUnits));
}
}
private async increaseBalanceAsync(tokenAddress: string, userAddress: string,
amountInBaseUnits: BigNumber.BigNumber): Promise<void> {
const balance = await this.getBalanceAsync(tokenAddress, userAddress);
this.setBalance(tokenAddress, userAddress, balance.plus(amountInBaseUnits));
}
private async decreaseBalanceAsync(tokenAddress: string, userAddress: string,
amountInBaseUnits: BigNumber.BigNumber): Promise<void> {
const balance = await this.getBalanceAsync(tokenAddress, userAddress);
this.setBalance(tokenAddress, userAddress, balance.minus(amountInBaseUnits));
}
private throwValidationError(failureReason: FailureReason, tradeSide: TradeSide,
transferType: TransferType): Promise<never> {
const errMsg = ERR_MSG_MAPPING[failureReason][tradeSide][transferType];
throw new Error(errMsg);
}
}
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