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import { abiUtils, BigNumber } from '@0xproject/utils';
import { Web3Wrapper } from '@0xproject/web3-wrapper';
import {
AbiDefinition,
AbiType,
ConstructorAbi,
ContractAbi,
DataItem,
MethodAbi,
Provider,
TxData,
TxDataPayable,
} from 'ethereum-types';
import * as ethers from 'ethers';
import { Interface } from 'ethers/utils/interface';
import * as _ from 'lodash';
import { formatABIDataItem } from './utils';
export interface EthersInterfaceByFunctionSignature {
[key: string]: Interface;
}
const REVERT_ERROR_SELECTOR = '08c379a0';
const REVERT_ERROR_SELECTOR_OFFSET = 2;
const REVERT_ERROR_SELECTOR_BYTES_LENGTH = 4;
const REVERT_ERROR_SELECTOR_END = REVERT_ERROR_SELECTOR_OFFSET + REVERT_ERROR_SELECTOR_BYTES_LENGTH * 2;
export class BaseContract {
protected _ethersInterfacesByFunctionSignature: EthersInterfaceByFunctionSignature;
protected _web3Wrapper: Web3Wrapper;
public abi: ContractAbi;
public address: string;
public contractName: string;
public constructorArgs: any[] = [];
protected static _formatABIDataItemList(
abis: DataItem[],
values: any[],
formatter: (type: string, value: any) => any,
): any {
return _.map(values, (value: any, i: number) => formatABIDataItem(abis[i], value, formatter));
}
protected static _lowercaseAddress(type: string, value: string): string {
return type === 'address' ? value.toLowerCase() : value;
}
protected static _bigNumberToString(_type: string, value: any): any {
return _.isObject(value) && value.isBigNumber ? value.toString() : value;
}
protected static _lookupConstructorAbi(abi: ContractAbi): ConstructorAbi {
const constructorAbiIfExists = _.find(
abi,
(abiDefinition: AbiDefinition) => abiDefinition.type === AbiType.Constructor,
// tslint:disable-next-line:no-unnecessary-type-assertion
) as ConstructorAbi | undefined;
if (!_.isUndefined(constructorAbiIfExists)) {
return constructorAbiIfExists;
} else {
// If the constructor is not explicitly defined, it won't be included in the ABI. It is
// still callable however, so we construct what the ABI would look like were it to exist.
const defaultConstructorAbi: ConstructorAbi = {
type: AbiType.Constructor,
stateMutability: 'nonpayable',
payable: false,
inputs: [],
};
return defaultConstructorAbi;
}
}
protected static _bnToBigNumber(_type: string, value: any): any {
return _.isObject(value) && value._hex ? new BigNumber(value.toString()) : value;
}
protected static async _applyDefaultsToTxDataAsync<T extends Partial<TxData | TxDataPayable>>(
txData: T,
txDefaults: Partial<TxData>,
estimateGasAsync?: (txData: T) => Promise<number>,
): Promise<TxData> {
// Gas amount sourced with the following priorities:
// 1. Optional param passed in to public method call
// 2. Global config passed in at library instantiation
// 3. Gas estimate calculation + safety margin
const removeUndefinedProperties = _.pickBy.bind(_);
const txDataWithDefaults = {
...removeUndefinedProperties(txDefaults),
...removeUndefinedProperties(txData),
};
if (_.isUndefined(txDataWithDefaults.gas) && !_.isUndefined(estimateGasAsync)) {
txDataWithDefaults.gas = await estimateGasAsync(txDataWithDefaults);
}
return txDataWithDefaults;
}
protected static _throwIfRevertWithReasonCallResult(rawCallResult: string): void {
if (rawCallResult.slice(REVERT_ERROR_SELECTOR_OFFSET, REVERT_ERROR_SELECTOR_END) === REVERT_ERROR_SELECTOR) {
const revertReason = ethers.utils.defaultAbiCoder.decode(
['string'],
ethers.utils.hexDataSlice(rawCallResult, REVERT_ERROR_SELECTOR_BYTES_LENGTH),
);
throw new Error(revertReason);
}
}
// Throws if the given arguments cannot be safely/correctly encoded based on
// the given inputAbi. An argument may not be considered safely encodeable
// if it overflows the corresponding Solidity type, there is a bug in the
// encoder, or the encoder performs unsafe type coercion.
public static strictArgumentEncodingCheck(inputAbi: DataItem[], args: any[]): void {
const coder = new ethers.utils.AbiCoder();
const params = abiUtils.parseEthersParams(inputAbi);
const rawEncoded = coder.encode(inputAbi, args);
const rawDecoded = coder.decode(inputAbi, rawEncoded);
for (let i = 0; i < rawDecoded.length; i++) {
const original = args[i];
const decoded = rawDecoded[i];
if (!abiUtils.isAbiDataEqual(params.names[i], params.types[i], original, decoded)) {
throw new Error(
`Cannot safely encode argument: ${params.names[i]} (${original}) of type ${
params.types[i]
}. (Possible type overflow or other encoding error)`,
);
}
}
}
protected _lookupEthersInterface(functionSignature: string): Interface {
const ethersInterface = this._ethersInterfacesByFunctionSignature[functionSignature];
if (_.isUndefined(ethersInterface)) {
throw new Error(`Failed to lookup method with function signature '${functionSignature}'`);
}
return ethersInterface;
}
protected _lookupAbi(functionSignature: string): MethodAbi {
const methodAbi = _.find(this.abi, (abiDefinition: AbiDefinition) => {
if (abiDefinition.type !== AbiType.Function) {
return false;
}
const abiFunctionSignature = abiUtils.getFunctionSignature(abiDefinition);
if (abiFunctionSignature === functionSignature) {
return true;
}
return false;
}) as MethodAbi;
return methodAbi;
}
constructor(
contractName: string,
abi: ContractAbi,
address: string,
provider: Provider,
txDefaults?: Partial<TxData>,
) {
this.contractName = contractName;
this._web3Wrapper = new Web3Wrapper(provider, txDefaults);
this.abi = abi;
this.address = address;
const methodAbis = this.abi.filter(
(abiDefinition: AbiDefinition) => abiDefinition.type === AbiType.Function,
) as MethodAbi[];
this._ethersInterfacesByFunctionSignature = {};
_.each(methodAbis, methodAbi => {
const functionSignature = abiUtils.getFunctionSignature(methodAbi);
this._ethersInterfacesByFunctionSignature[functionSignature] = new Interface([methodAbi]);
});
}
}
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