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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<ContractEventArgs>};
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;
}
/**
* Cancels all existing subscriptions
*/
public 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._blockAndLogStreamer)) {
this._startBlockAndLogStream();
}
const filterToken = filterUtils.generateUUID();
this._filters[filterToken] = filter;
this._filterCallbacks[filterToken] = callback;
return filterToken;
}
protected async _getLogsAsync<ArgsType extends ContractEventArgs>(
address: string, eventName: ContractEvents, subscriptionOpts: SubscriptionOpts,
indexFilterValues: IndexedFilterValues, abi: Web3.ContractAbi): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
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<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<ContractType extends Web3.ContractInstance>(
artifact: Artifact, addressIfExists?: string): Promise<ContractType> {
const contractInstance =
await this._web3Wrapper.getContractInstanceFromArtifactAsync<ContractType>(artifact, addressIfExists);
return contractInstance;
}
private _onLogStateChanged<ArgsType extends ContractEventArgs>(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<ArgsType>;
const logEvent = {
...decodedLog,
removed,
};
this._filterCallbacks[filterToken](null, 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<void> {
try {
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);
}
} catch (err) {
const filterTokens = _.keys(this._filterCallbacks);
_.each(filterTokens, filterToken => {
this._unsubscribe(filterToken, err);
});
}
}
}
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