import * as _ from 'lodash'; import * as BigNumber from 'bignumber.js'; import {Web3Wrapper} from '../web3_wrapper'; import {assert} from '../utils/assert'; import {constants} from '../utils/constants'; import {ContractWrapper} from './contract_wrapper'; import * as TokenArtifacts from '../artifacts/Token.json'; import * as ProxyArtifacts from '../artifacts/Proxy.json'; import {TokenContract, ZeroExError} from '../types'; const ALLOWANCE_TO_ZERO_GAS_AMOUNT = 45730; export class TokenWrapper extends ContractWrapper { private tokenContractsByAddress: {[address: string]: TokenContract}; constructor(web3Wrapper: Web3Wrapper) { super(web3Wrapper); this.tokenContractsByAddress = {}; } public invalidateContractInstances() { this.tokenContractsByAddress = {}; } /** * Returns an owner's ERC20 token balance. */ public async getBalanceAsync(tokenAddress: string, ownerAddress: string): Promise { assert.isETHAddressHex('ownerAddress', ownerAddress); assert.isETHAddressHex('tokenAddress', tokenAddress); const tokenContract = await this.getTokenContractAsync(tokenAddress); let balance = await tokenContract.balanceOf.call(ownerAddress); // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber balance = new BigNumber(balance); return balance; } /** * Retrieves the allowance in baseUnits of the ERC20 token set to the 0x proxy contract * by an owner address. */ public async getProxyAllowanceAsync(tokenAddress: string, ownerAddress: string) { assert.isETHAddressHex('ownerAddress', ownerAddress); assert.isETHAddressHex('tokenAddress', tokenAddress); const tokenContract = await this.getTokenContractAsync(tokenAddress); const proxyAddress = await this.getProxyAddressAsync(); let allowanceInBaseUnits = await tokenContract.allowance.call(ownerAddress, proxyAddress); // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber allowanceInBaseUnits = new BigNumber(allowanceInBaseUnits); return allowanceInBaseUnits; } /** * Sets the 0x proxy contract's allowance to a specified number of a tokens' baseUnits on behalf * of an owner address. */ public async setProxyAllowanceAsync(tokenAddress: string, ownerAddress: string, amountInBaseUnits: BigNumber.BigNumber): Promise { assert.isETHAddressHex('ownerAddress', ownerAddress); assert.isETHAddressHex('tokenAddress', tokenAddress); assert.isBigNumber('amountInBaseUnits', amountInBaseUnits); const tokenContract = await this.getTokenContractAsync(tokenAddress); const proxyAddress = await this.getProxyAddressAsync(); // Hack: for some reason default estimated gas amount causes `base fee exceeds gas limit` exception // on testrpc. Probably related to https://github.com/ethereumjs/testrpc/issues/294 // TODO: Debug issue in testrpc and submit a PR, then remove this hack const networkIdIfExists = await this.web3Wrapper.getNetworkIdIfExistsAsync(); const gas = networkIdIfExists === constants.TESTRPC_NETWORK_ID ? ALLOWANCE_TO_ZERO_GAS_AMOUNT : undefined; await tokenContract.approve(proxyAddress, amountInBaseUnits, { from: ownerAddress, gas, }); } /** * Transfers `amountInBaseUnits` ERC20 tokens from `fromAddress` to `toAddress`. */ public async transferAsync(tokenAddress: string, fromAddress: string, toAddress: string, amountInBaseUnits: BigNumber.BigNumber): Promise { assert.isETHAddressHex('tokenAddress', tokenAddress); assert.isETHAddressHex('fromAddress', fromAddress); assert.isETHAddressHex('toAddress', toAddress); assert.isBigNumber('amountInBaseUnits', amountInBaseUnits); const tokenContract = await this.getTokenContractAsync(tokenAddress); await tokenContract.transfer(toAddress, amountInBaseUnits, { from: fromAddress, }); } private async getTokenContractAsync(tokenAddress: string): Promise { let tokenContract = this.tokenContractsByAddress[tokenAddress]; if (!_.isUndefined(tokenContract)) { return tokenContract; } const contractInstance = await this.instantiateContractIfExistsAsync((TokenArtifacts as any), tokenAddress); tokenContract = contractInstance as TokenContract; this.tokenContractsByAddress[tokenAddress] = tokenContract; return tokenContract; } private async getProxyAddressAsync() { const networkIdIfExists = await this.web3Wrapper.getNetworkIdIfExistsAsync(); const proxyNetworkConfigsIfExists = _.isUndefined(networkIdIfExists) ? undefined : (ProxyArtifacts as any).networks[networkIdIfExists]; if (_.isUndefined(proxyNetworkConfigsIfExists)) { throw new Error(ZeroExError.CONTRACT_NOT_DEPLOYED_ON_NETWORK); } const proxyAddress = proxyNetworkConfigsIfExists.address; return proxyAddress; } }