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import { BlockParamLiteral, 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,
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;
protected _networkId: number;
private _abiDecoder?: AbiDecoder;
private _blockAndLogStreamerIfExists?: BlockAndLogStreamer;
private _blockAndLogStreamIntervalIfExists?: NodeJS.Timer;
private _filters: { [filterToken: string]: Web3.FilterObject };
private _filterCallbacks: {
[filterToken: string]: EventCallback<ContractEventArgs>;
};
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<ArgsType extends ContractEventArgs>(
address: string,
eventName: ContractEvents,
indexFilterValues: IndexedFilterValues,
abi: Web3.ContractAbi,
callback: EventCallback<ArgsType>,
): 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<ContractEventArgs>;
return filterToken;
}
protected async _getLogsAsync<ArgsType extends ContractEventArgs>(
address: string,
eventName: ContractEvents,
blockRange: BlockRange,
indexFilterValues: IndexedFilterValues,
abi: Web3.ContractAbi,
): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
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<ArgsType extends ContractEventArgs>(
log: Web3.LogEntry,
): LogWithDecodedArgs<ArgsType> | 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<Web3.ContractInstance> {
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<ArgsType extends ContractEventArgs>(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<ArgsType>;
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._blockAndLogStreamIntervalIfExists = 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._blockAndLogStreamIntervalIfExists as NodeJS.Timer);
delete this._blockAndLogStreamerIfExists;
}
private async _reconcileBlockAsync(): Promise<void> {
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);
}
}
}
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