import { LogWithDecodedArgs, RawLog } from '@0xproject/types'; import { AbiDecoder, intervalUtils } from '@0xproject/utils'; import { Web3Wrapper } from '@0xproject/web3-wrapper'; import { Block, BlockAndLogStreamer } from 'ethereumjs-blockstream'; import * as _ from 'lodash'; import * as Web3 from 'web3'; import { Artifact, BlockParamLiteral, BlockRange, ContractEventArgs, ContractEvents, EventCallback, IndexedFilterValues, InternalZeroExError, ZeroExError, } from '../types'; import { constants } from '../utils/constants'; import { filterUtils } from '../utils/filter_utils'; const CONTRACT_NAME_TO_NOT_FOUND_ERROR: { [contractName: string]: ZeroExError; } = { ZRX: ZeroExError.ZRXContractDoesNotExist, EtherToken: ZeroExError.EtherTokenContractDoesNotExist, Token: ZeroExError.TokenContractDoesNotExist, TokenRegistry: ZeroExError.TokenRegistryContractDoesNotExist, TokenTransferProxy: ZeroExError.TokenTransferProxyContractDoesNotExist, Exchange: ZeroExError.ExchangeContractDoesNotExist, }; export class ContractWrapper { protected _web3Wrapper: Web3Wrapper; private _networkId: number; private _abiDecoder?: AbiDecoder; private _blockAndLogStreamerIfExists: BlockAndLogStreamer | undefined; private _blockAndLogStreamInterval: NodeJS.Timer; private _filters: { [filterToken: string]: Web3.FilterObject }; private _filterCallbacks: { [filterToken: string]: EventCallback; }; private _onLogAddedSubscriptionToken: string | undefined; private _onLogRemovedSubscriptionToken: string | undefined; constructor(web3Wrapper: Web3Wrapper, networkId: number, abiDecoder?: AbiDecoder) { this._web3Wrapper = web3Wrapper; this._networkId = networkId; this._abiDecoder = abiDecoder; this._filters = {}; this._filterCallbacks = {}; this._blockAndLogStreamerIfExists = undefined; this._onLogAddedSubscriptionToken = undefined; this._onLogRemovedSubscriptionToken = undefined; } protected unsubscribeAll(): void { const filterTokens = _.keys(this._filterCallbacks); _.each(filterTokens, filterToken => { this._unsubscribe(filterToken); }); } protected _unsubscribe(filterToken: string, err?: Error): void { if (_.isUndefined(this._filters[filterToken])) { throw new Error(ZeroExError.SubscriptionNotFound); } if (!_.isUndefined(err)) { const callback = this._filterCallbacks[filterToken]; callback(err, undefined); } delete this._filters[filterToken]; delete this._filterCallbacks[filterToken]; if (_.isEmpty(this._filters)) { this._stopBlockAndLogStream(); } } protected _subscribe( address: string, eventName: ContractEvents, indexFilterValues: IndexedFilterValues, abi: Web3.ContractAbi, callback: EventCallback, ): string { const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi); if (_.isUndefined(this._blockAndLogStreamerIfExists)) { this._startBlockAndLogStream(); } const filterToken = filterUtils.generateUUID(); this._filters[filterToken] = filter; this._filterCallbacks[filterToken] = callback as EventCallback; return filterToken; } protected async _getLogsAsync( address: string, eventName: ContractEvents, blockRange: BlockRange, indexFilterValues: IndexedFilterValues, abi: Web3.ContractAbi, ): Promise>> { const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi, blockRange); const logs = await this._web3Wrapper.getLogsAsync(filter); const logsWithDecodedArguments = _.map(logs, this._tryToDecodeLogOrNoop.bind(this)); return logsWithDecodedArguments; } protected _tryToDecodeLogOrNoop( log: Web3.LogEntry, ): LogWithDecodedArgs | RawLog { if (_.isUndefined(this._abiDecoder)) { throw new Error(InternalZeroExError.NoAbiDecoder); } const logWithDecodedArgs = this._abiDecoder.tryToDecodeLogOrNoop(log); return logWithDecodedArgs; } protected async _instantiateContractIfExistsAsync( artifact: Artifact, addressIfExists?: string, ): Promise { let contractAddress: string; if (_.isUndefined(addressIfExists)) { if (_.isUndefined(artifact.networks[this._networkId])) { throw new Error(ZeroExError.ContractNotDeployedOnNetwork); } contractAddress = artifact.networks[this._networkId].address.toLowerCase(); } else { contractAddress = addressIfExists; } const doesContractExist = await this._web3Wrapper.doesContractExistAtAddressAsync(contractAddress); if (!doesContractExist) { throw new Error(CONTRACT_NAME_TO_NOT_FOUND_ERROR[artifact.contract_name]); } const contractInstance = this._web3Wrapper.getContractInstance(artifact.abi, contractAddress); return contractInstance; } protected _getContractAddress(artifact: Artifact, addressIfExists?: string): string { if (_.isUndefined(addressIfExists)) { const contractAddress = artifact.networks[this._networkId].address; if (_.isUndefined(contractAddress)) { throw new Error(ZeroExError.ExchangeContractDoesNotExist); } return contractAddress; } else { return addressIfExists; } } private _onLogStateChanged(isRemoved: boolean, log: Web3.LogEntry): void { _.forEach(this._filters, (filter: Web3.FilterObject, filterToken: string) => { if (filterUtils.matchesFilter(log, filter)) { const decodedLog = this._tryToDecodeLogOrNoop(log) as LogWithDecodedArgs; const logEvent = { log: decodedLog, isRemoved, }; this._filterCallbacks[filterToken](null, logEvent); } }); } private _startBlockAndLogStream(): void { if (!_.isUndefined(this._blockAndLogStreamerIfExists)) { throw new Error(ZeroExError.SubscriptionAlreadyPresent); } this._blockAndLogStreamerIfExists = new BlockAndLogStreamer( this._web3Wrapper.getBlockAsync.bind(this._web3Wrapper), this._web3Wrapper.getLogsAsync.bind(this._web3Wrapper), ); const catchAllLogFilter = {}; this._blockAndLogStreamerIfExists.addLogFilter(catchAllLogFilter); this._blockAndLogStreamInterval = intervalUtils.setAsyncExcludingInterval( this._reconcileBlockAsync.bind(this), constants.DEFAULT_BLOCK_POLLING_INTERVAL, this._onReconcileBlockError.bind(this), ); let isRemoved = false; this._onLogAddedSubscriptionToken = this._blockAndLogStreamerIfExists.subscribeToOnLogAdded( this._onLogStateChanged.bind(this, isRemoved), ); isRemoved = true; this._onLogRemovedSubscriptionToken = this._blockAndLogStreamerIfExists.subscribeToOnLogRemoved( this._onLogStateChanged.bind(this, isRemoved), ); } private _onReconcileBlockError(err: Error): void { const filterTokens = _.keys(this._filterCallbacks); _.each(filterTokens, filterToken => { this._unsubscribe(filterToken, err); }); } private _setNetworkId(networkId: number): void { this._networkId = networkId; } private _stopBlockAndLogStream(): void { if (_.isUndefined(this._blockAndLogStreamerIfExists)) { throw new Error(ZeroExError.SubscriptionNotFound); } this._blockAndLogStreamerIfExists.unsubscribeFromOnLogAdded(this._onLogAddedSubscriptionToken as string); this._blockAndLogStreamerIfExists.unsubscribeFromOnLogRemoved(this._onLogRemovedSubscriptionToken as string); intervalUtils.clearAsyncExcludingInterval(this._blockAndLogStreamInterval); delete this._blockAndLogStreamerIfExists; } private async _reconcileBlockAsync(): Promise { const latestBlock = await this._web3Wrapper.getBlockAsync(BlockParamLiteral.Latest); // We need to coerce to Block type cause Web3.Block includes types for mempool blocks if (!_.isUndefined(this._blockAndLogStreamerIfExists)) { // If we clear the interval while fetching the block - this._blockAndLogStreamer will be undefined await this._blockAndLogStreamerIfExists.reconcileNewBlock((latestBlock as any) as Block); } } }