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import * as _ from 'lodash';
import {schemas} from '0x-json-schemas';
import * as ethUtil from 'ethereumjs-util';
import {ZeroEx} from '../0x';
import {EventWatcher} from './event_watcher';
import {assert} from '../utils/assert';
import {utils} from '../utils/utils';
import {artifacts} from '../artifacts';
import {AbiDecoder} from '../utils/abi_decoder';
import {OrderStateUtils} from '../utils/order_state_utils';
import {
LogEvent,
OrderState,
SignedOrder,
Web3Provider,
BlockParamLiteral,
LogWithDecodedArgs,
OnOrderStateChangeCallback,
OrderStateWatcherConfig,
ExchangeEvents,
TokenEvents,
ZeroExError,
} from '../types';
import {Web3Wrapper} from '../web3_wrapper';
const DEFAULT_NUM_CONFIRMATIONS = 0;
interface DependentOrderHashes {
[makerAddress: string]: {
[makerToken: string]: Set<string>,
};
}
interface OrderByOrderHash {
[orderHash: string]: SignedOrder;
}
/**
* This class includes all the functionality related to watching a set of orders
* for potential changes in order validity/fillability. The orderWatcher notifies
* the subscriber of these changes so that a final decison can be made on whether
* the order should be deemed invalid.
*/
export class OrderStateWatcher {
private _orderByOrderHash: OrderByOrderHash = {};
private _dependentOrderHashes: DependentOrderHashes = {};
private _web3Wrapper: Web3Wrapper;
private _callbackIfExistsAsync?: OnOrderStateChangeCallback;
private _eventWatcher: EventWatcher;
private _abiDecoder: AbiDecoder;
private _orderStateUtils: OrderStateUtils;
private _numConfirmations: number;
constructor(
web3Wrapper: Web3Wrapper, abiDecoder: AbiDecoder, orderStateUtils: OrderStateUtils,
config?: OrderStateWatcherConfig,
) {
this._web3Wrapper = web3Wrapper;
const eventPollingIntervalMs = _.isUndefined(config) ? undefined : config.pollingIntervalMs;
this._numConfirmations = _.isUndefined(config) ?
DEFAULT_NUM_CONFIRMATIONS
: config.numConfirmations;
this._eventWatcher = new EventWatcher(
this._web3Wrapper, eventPollingIntervalMs, this._numConfirmations,
);
this._abiDecoder = abiDecoder;
this._orderStateUtils = orderStateUtils;
}
/**
* Add an order to the orderStateWatcher. Before the order is added, it's
* signature is verified.
* @param signedOrder The order you wish to start watching.
*/
public addOrder(signedOrder: SignedOrder): void {
assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
const orderHash = ZeroEx.getOrderHashHex(signedOrder);
assert.isValidSignature(orderHash, signedOrder.ecSignature, signedOrder.maker);
this._orderByOrderHash[orderHash] = signedOrder;
this.addToDependentOrderHashes(signedOrder, orderHash);
}
/**
* Removes an order from the orderStateWatcher
* @param orderHash The orderHash of the order you wish to stop watching.
*/
public removeOrder(orderHash: string): void {
assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
const signedOrder = this._orderByOrderHash[orderHash];
if (_.isUndefined(signedOrder)) {
return; // noop
}
delete this._orderByOrderHash[orderHash];
this.removeFromDependentOrderHashes(signedOrder.maker, signedOrder.makerTokenAddress, orderHash);
}
/**
* Starts an orderStateWatcher subscription. The callback will be called every time a watched order's
* backing blockchain state has changed. This is a call-to-action for the caller to re-validate the order.
* @param callback Receives the orderHash of the order that should be re-validated, together
* with all the order-relevant blockchain state needed to re-validate the order.
*/
public subscribe(callback: OnOrderStateChangeCallback): void {
assert.isFunction('callback', callback);
if (!_.isUndefined(this._callbackIfExistsAsync)) {
throw new Error(ZeroExError.SubscriptionAlreadyPresent);
}
this._callbackIfExistsAsync = callback;
this._eventWatcher.subscribe(this._onEventWatcherCallbackAsync.bind(this));
}
/**
* Ends an orderStateWatcher subscription.
*/
public unsubscribe(): void {
delete this._callbackIfExistsAsync;
this._eventWatcher.unsubscribe();
}
private async _onEventWatcherCallbackAsync(log: LogEvent): Promise<void> {
const maybeDecodedLog = this._abiDecoder.tryToDecodeLogOrNoop(log);
const isLogDecoded = !_.isUndefined((maybeDecodedLog as LogWithDecodedArgs<any>).event);
if (!isLogDecoded) {
return; // noop
}
// Unfortunately blockNumber is returned as a hex-encoded string, so we
// convert it to a number here.
const blockNumberBuff = ethUtil.toBuffer(maybeDecodedLog.blockNumber);
const blockNumber = ethUtil.bufferToInt(blockNumberBuff);
const decodedLog = maybeDecodedLog as LogWithDecodedArgs<any>;
let makerToken: string;
let makerAddress: string;
let orderHashesSet: Set<string>;
switch (decodedLog.event) {
case TokenEvents.Approval:
makerToken = decodedLog.address;
makerAddress = decodedLog.args._owner;
orderHashesSet = _.get(this._dependentOrderHashes, [makerAddress, makerToken]);
if (!_.isUndefined(orderHashesSet)) {
const orderHashes = Array.from(orderHashesSet);
await this._emitRevalidateOrdersAsync(orderHashes, blockNumber);
}
break;
case TokenEvents.Transfer:
makerToken = decodedLog.address;
makerAddress = decodedLog.args._from;
orderHashesSet = _.get(this._dependentOrderHashes, [makerAddress, makerToken]);
if (!_.isUndefined(orderHashesSet)) {
const orderHashes = Array.from(orderHashesSet);
await this._emitRevalidateOrdersAsync(orderHashes, blockNumber);
}
break;
case ExchangeEvents.LogFill:
case ExchangeEvents.LogCancel:
const orderHash = decodedLog.args.orderHash;
const isOrderWatched = !_.isUndefined(this._orderByOrderHash[orderHash]);
if (isOrderWatched) {
await this._emitRevalidateOrdersAsync([orderHash], blockNumber);
}
break;
case ExchangeEvents.LogError:
return; // noop
default:
throw utils.spawnSwitchErr('decodedLog.event', decodedLog.event);
}
}
private async _emitRevalidateOrdersAsync(orderHashes: string[], blockNumber: number): Promise<void> {
const defaultBlock = this._numConfirmations === 0 ?
BlockParamLiteral.Pending :
blockNumber;
const methodOpts = {
defaultBlock,
};
for (const orderHash of orderHashes) {
const signedOrder = this._orderByOrderHash[orderHash] as SignedOrder;
const orderState = await this._orderStateUtils.getOrderStateAsync(signedOrder, methodOpts);
if (!_.isUndefined(this._callbackIfExistsAsync)) {
await this._callbackIfExistsAsync(orderState);
} else {
break; // Unsubscribe was called
}
}
}
private addToDependentOrderHashes(signedOrder: SignedOrder, orderHash: string) {
if (_.isUndefined(this._dependentOrderHashes[signedOrder.maker])) {
this._dependentOrderHashes[signedOrder.maker] = {};
}
if (_.isUndefined(this._dependentOrderHashes[signedOrder.maker][signedOrder.makerTokenAddress])) {
this._dependentOrderHashes[signedOrder.maker][signedOrder.makerTokenAddress] = new Set();
}
this._dependentOrderHashes[signedOrder.maker][signedOrder.makerTokenAddress].add(orderHash);
}
private removeFromDependentOrderHashes(makerAddress: string, makerTokenAddress: string, orderHash: string) {
this._dependentOrderHashes[makerAddress][makerTokenAddress].delete(orderHash);
if (this._dependentOrderHashes[makerAddress][makerTokenAddress].size === 0) {
delete this._dependentOrderHashes[makerAddress][makerTokenAddress];
}
if (_.isEmpty(this._dependentOrderHashes[makerAddress])) {
delete this._dependentOrderHashes[makerAddress];
}
}
}
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