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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, InternalError} 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<BigNumber.BigNumber> {
assert.isETHAddressHex('ownerAddress', ownerAddress);
assert.isETHAddressHex('tokenAddress', tokenAddress);
const tokenContract = await this.getTokenContractAsync(tokenAddress);
let balance = await tokenContract.balanceOf.call(ownerAddress);
// The BigNumber instance returned by Web3 is of a much older version then our own, we therefore
// should always re-instantiate the returned BigNumber after retrieval.
balance = _.isUndefined(balance) ? new BigNumber(0) : 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);
allowanceInBaseUnits = _.isUndefined(allowanceInBaseUnits) ?
new BigNumber(0) :
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) {
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,
});
}
private async getTokenContractAsync(tokenAddress: string): Promise<TokenContract> {
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(InternalError.PROXY_ADDRESS_NOT_FOUND);
}
const proxyAddress = proxyNetworkConfigsIfExists.address;
return proxyAddress;
}
}
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