import * as _ from 'lodash'; import * as Web3 from 'web3'; import {BlockAndLogStreamer, Block} from 'ethereumjs-blockstream'; import {Web3Wrapper} from '../web3_wrapper'; import {AbiDecoder} from '../utils/abi_decoder'; import { ZeroExError, InternalZeroExError, Artifact, LogWithDecodedArgs, RawLog, ContractEvents, SubscriptionOpts, IndexedFilterValues, EventCallback, BlockParamLiteral, ContractEventArgs, } from '../types'; import {constants} from '../utils/constants'; import {intervalUtils} from '../utils/interval_utils'; import {filterUtils} from '../utils/filter_utils'; export class ContractWrapper { protected _web3Wrapper: Web3Wrapper; private _abiDecoder?: AbiDecoder; private _blockAndLogStreamer: 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, abiDecoder?: AbiDecoder) { this._web3Wrapper = web3Wrapper; this._abiDecoder = abiDecoder; this._filters = {}; this._filterCallbacks = {}; this._blockAndLogStreamer = undefined; this._onLogAddedSubscriptionToken = undefined; this._onLogRemovedSubscriptionToken = undefined; } 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._blockAndLogStreamer)) { this._startBlockAndLogStream(); } const filterToken = filterUtils.generateUUID(); this._filters[filterToken] = filter; this._filterCallbacks[filterToken] = callback; return filterToken; } protected _unsubscribe(filterToken: string): void { if (_.isUndefined(this._filters[filterToken])) { throw new Error(ZeroExError.SubscriptionNotFound); } delete this._filters[filterToken]; delete this._filterCallbacks[filterToken]; if (_.isEmpty(this._filters)) { this._stopBlockAndLogStream(); } } protected async _getLogsAsync( address: string, eventName: ContractEvents, subscriptionOpts: SubscriptionOpts, indexFilterValues: IndexedFilterValues, abi: Web3.ContractAbi): Promise>> { const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi, subscriptionOpts); 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 { const contractInstance = await this._web3Wrapper.getContractInstanceFromArtifactAsync(artifact, addressIfExists); return contractInstance; } private _onLogStateChanged(removed: 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 = { ...decodedLog, removed, }; this._filterCallbacks[filterToken](logEvent); } }); } private _startBlockAndLogStream(): void { this._blockAndLogStreamer = new BlockAndLogStreamer( this._web3Wrapper.getBlockAsync.bind(this._web3Wrapper), this._web3Wrapper.getLogsAsync.bind(this._web3Wrapper), ); const catchAllLogFilter = {}; this._blockAndLogStreamer.addLogFilter(catchAllLogFilter); this._blockAndLogStreamInterval = intervalUtils.setAsyncExcludingInterval( this._reconcileBlockAsync.bind(this), constants.DEFAULT_BLOCK_POLLING_INTERVAL, ); let removed = false; this._onLogAddedSubscriptionToken = this._blockAndLogStreamer.subscribeToOnLogAdded( this._onLogStateChanged.bind(this, removed), ); removed = true; this._onLogRemovedSubscriptionToken = this._blockAndLogStreamer.subscribeToOnLogRemoved( this._onLogStateChanged.bind(this, removed), ); } private _stopBlockAndLogStream(): void { (this._blockAndLogStreamer as BlockAndLogStreamer).unsubscribeFromOnLogAdded( this._onLogAddedSubscriptionToken as string); (this._blockAndLogStreamer as BlockAndLogStreamer).unsubscribeFromOnLogRemoved( this._onLogRemovedSubscriptionToken as string); intervalUtils.clearAsyncExcludingInterval(this._blockAndLogStreamInterval); delete this._blockAndLogStreamer; } 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._blockAndLogStreamer)) { // If we clear the interval while fetching the block - this._blockAndLogStreamer will be undefined this._blockAndLogStreamer.reconcileNewBlock(latestBlock as any as Block); } } }