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import { AbiDecoder, intervalUtils, logUtils } from '@0xproject/utils';
import { marshaller, Web3Wrapper } from '@0xproject/web3-wrapper';
import {
BlockParamLiteral,
ContractAbi,
FilterObject,
LogEntry,
LogWithDecodedArgs,
RawLog,
RawLogEntry,
} from 'ethereum-types';
import { Block, BlockAndLogStreamer, Log } from 'ethereumjs-blockstream';
import * as _ from 'lodash';
import {
BlockRange,
ContractEventArgs,
ContractEvents,
ContractWrappersError,
EventCallback,
IndexedFilterValues,
} from '../types';
import { constants } from '../utils/constants';
import { filterUtils } from '../utils/filter_utils';
export abstract class ContractWrapper {
public abstract abi: ContractAbi;
protected _networkId: number;
protected _web3Wrapper: Web3Wrapper;
private _blockAndLogStreamerIfExists: BlockAndLogStreamer<Block, Log> | undefined;
private _blockPollingIntervalMs: number;
private _blockAndLogStreamIntervalIfExists?: NodeJS.Timer;
private _filters: { [filterToken: string]: FilterObject };
private _filterCallbacks: {
[filterToken: string]: EventCallback<ContractEventArgs>;
};
private _onLogAddedSubscriptionToken: string | undefined;
private _onLogRemovedSubscriptionToken: string | undefined;
private static _onBlockAndLogStreamerError(isVerbose: boolean, err: Error): void {
// Since Blockstream errors are all recoverable, we simply log them if the verbose
// config is passed in.
if (isVerbose) {
logUtils.warn(err);
}
}
constructor(web3Wrapper: Web3Wrapper, networkId: number, blockPollingIntervalMs?: number) {
this._web3Wrapper = web3Wrapper;
this._networkId = networkId;
this._blockPollingIntervalMs = _.isUndefined(blockPollingIntervalMs)
? constants.DEFAULT_BLOCK_POLLING_INTERVAL
: blockPollingIntervalMs;
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(ContractWrappersError.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: ContractAbi,
callback: EventCallback<ArgsType>,
isVerbose: boolean = false,
): string {
const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi);
if (_.isUndefined(this._blockAndLogStreamerIfExists)) {
this._startBlockAndLogStream(isVerbose);
}
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: 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: LogEntry,
): LogWithDecodedArgs<ArgsType> | RawLog {
const abiDecoder = new AbiDecoder([this.abi]);
const logWithDecodedArgs = abiDecoder.tryToDecodeLogOrNoop(log);
return logWithDecodedArgs;
}
private _onLogStateChanged<ArgsType extends ContractEventArgs>(isRemoved: boolean, rawLog: RawLogEntry): void {
const log: LogEntry = marshaller.unmarshalLog(rawLog);
_.forEach(this._filters, (filter: 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(isVerbose: boolean): void {
if (!_.isUndefined(this._blockAndLogStreamerIfExists)) {
throw new Error(ContractWrappersError.SubscriptionAlreadyPresent);
}
this._blockAndLogStreamerIfExists = new BlockAndLogStreamer(
this._blockstreamGetBlockOrNullAsync.bind(this),
this._blockstreamGetLogsAsync.bind(this),
ContractWrapper._onBlockAndLogStreamerError.bind(this, isVerbose),
);
const catchAllLogFilter = {};
this._blockAndLogStreamerIfExists.addLogFilter(catchAllLogFilter);
this._blockAndLogStreamIntervalIfExists = intervalUtils.setAsyncExcludingInterval(
this._reconcileBlockAsync.bind(this),
this._blockPollingIntervalMs,
ContractWrapper._onBlockAndLogStreamerError.bind(this, isVerbose),
);
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),
);
}
// This method only exists in order to comply with the expected interface of Blockstream's constructor
private async _blockstreamGetBlockOrNullAsync(hash: string): Promise<Block | null> {
const shouldIncludeTransactionData = false;
const blockOrNull = await this._web3Wrapper.sendRawPayloadAsync<Block | null>({
method: 'eth_getBlockByHash',
params: [hash, shouldIncludeTransactionData],
});
return blockOrNull;
}
// This method only exists in order to comply with the expected interface of Blockstream's constructor
private async _blockstreamGetLatestBlockOrNullAsync(): Promise<Block | null> {
const shouldIncludeTransactionData = false;
const blockOrNull = await this._web3Wrapper.sendRawPayloadAsync<Block | null>({
method: 'eth_getBlockByNumber',
params: [BlockParamLiteral.Latest, shouldIncludeTransactionData],
});
return blockOrNull;
}
// This method only exists in order to comply with the expected interface of Blockstream's constructor
private async _blockstreamGetLogsAsync(filterOptions: FilterObject): Promise<RawLogEntry[]> {
const logs = await this._web3Wrapper.sendRawPayloadAsync<RawLogEntry[]>({
method: 'eth_getLogs',
params: [filterOptions],
});
return logs as RawLogEntry[];
}
private _stopBlockAndLogStream(): void {
if (_.isUndefined(this._blockAndLogStreamerIfExists)) {
throw new Error(ContractWrappersError.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 latestBlockOrNull = await this._blockstreamGetLatestBlockOrNullAsync();
if (_.isNull(latestBlockOrNull)) {
return; // noop
}
// 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(latestBlockOrNull);
}
}
}
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