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author | Fabio Berger <me@fabioberger.com> | 2018-05-10 02:36:28 +0800 |
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committer | Fabio Berger <me@fabioberger.com> | 2018-05-10 02:36:28 +0800 |
commit | 209266dbed9d7d038c90c2da8d9b99acab77c80c (patch) | |
tree | cfefd5ab15bc237716b15687629e0f41362a8e86 /packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts | |
parent | 69a6166b6a1d39afc24b8dd950ec5d8539a03420 (diff) | |
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Split 0x.js into contract-wrappers, order-watcher but keep 0x.js as a unifying library with the same interface
Diffstat (limited to 'packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts')
-rw-r--r-- | packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts b/packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts new file mode 100644 index 000000000..b575285a1 --- /dev/null +++ b/packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts @@ -0,0 +1,115 @@ +import { BlockParamLiteral, ExchangeContractErrs } from '@0xproject/types'; +import { BigNumber } from '@0xproject/utils'; +import * as _ from 'lodash'; + +import { TokenWrapper } from '../contract_wrappers/token_wrapper'; +import { BalanceAndProxyAllowanceLazyStore } from '../stores/balance_proxy_allowance_lazy_store'; +import { TradeSide, TransferType } from '../types'; +import { constants } from '../utils/constants'; + +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, + }, + }, +}; + +export class ExchangeTransferSimulator { + private _store: BalanceAndProxyAllowanceLazyStore; + private _UNLIMITED_ALLOWANCE_IN_BASE_UNITS: BigNumber; + private static _throwValidationError( + failureReason: FailureReason, + tradeSide: TradeSide, + transferType: TransferType, + ): never { + const errMsg = ERR_MSG_MAPPING[failureReason][tradeSide][transferType]; + throw new Error(errMsg); + } + constructor(token: TokenWrapper, defaultBlock: BlockParamLiteral) { + this._store = new BalanceAndProxyAllowanceLazyStore(token, defaultBlock); + this._UNLIMITED_ALLOWANCE_IN_BASE_UNITS = token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS; + } + /** + * Simulates transferFrom call performed by a proxy + * @param tokenAddress Address of the token to be transferred + * @param from Owner of the transferred tokens + * @param to Recipient of the transferred tokens + * @param amountInBaseUnits The amount of tokens being transferred + * @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, + tradeSide: TradeSide, + transferType: TransferType, + ): Promise<void> { + // HACK: When simulating an open order (e.g taker is NULL_ADDRESS), we don't want to adjust balances/ + // allowances for the taker. We do however, want to increase the balance of the maker since the maker + // might be relying on those funds to fill subsequent orders or pay the order's fees. + if (from === constants.NULL_ADDRESS && tradeSide === TradeSide.Taker) { + await this._increaseBalanceAsync(tokenAddress, to, amountInBaseUnits); + return; + } + const balance = await this._store.getBalanceAsync(tokenAddress, from); + const proxyAllowance = await this._store.getProxyAllowanceAsync(tokenAddress, from); + if (proxyAllowance.lessThan(amountInBaseUnits)) { + ExchangeTransferSimulator._throwValidationError(FailureReason.ProxyAllowance, tradeSide, transferType); + } + if (balance.lessThan(amountInBaseUnits)) { + ExchangeTransferSimulator._throwValidationError(FailureReason.Balance, tradeSide, transferType); + } + await this._decreaseProxyAllowanceAsync(tokenAddress, from, amountInBaseUnits); + await this._decreaseBalanceAsync(tokenAddress, from, amountInBaseUnits); + await this._increaseBalanceAsync(tokenAddress, to, amountInBaseUnits); + } + private async _decreaseProxyAllowanceAsync( + tokenAddress: string, + userAddress: string, + amountInBaseUnits: BigNumber, + ): Promise<void> { + const proxyAllowance = await this._store.getProxyAllowanceAsync(tokenAddress, userAddress); + if (!proxyAllowance.eq(this._UNLIMITED_ALLOWANCE_IN_BASE_UNITS)) { + this._store.setProxyAllowance(tokenAddress, userAddress, proxyAllowance.minus(amountInBaseUnits)); + } + } + private async _increaseBalanceAsync( + tokenAddress: string, + userAddress: string, + amountInBaseUnits: BigNumber, + ): Promise<void> { + const balance = await this._store.getBalanceAsync(tokenAddress, userAddress); + this._store.setBalance(tokenAddress, userAddress, balance.plus(amountInBaseUnits)); + } + private async _decreaseBalanceAsync( + tokenAddress: string, + userAddress: string, + amountInBaseUnits: BigNumber, + ): Promise<void> { + const balance = await this._store.getBalanceAsync(tokenAddress, userAddress); + this._store.setBalance(tokenAddress, userAddress, balance.minus(amountInBaseUnits)); + } +} |