63 lines
1.7 KiB
TypeScript
63 lines
1.7 KiB
TypeScript
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import { ContractEvent } from "./ContractEvent"
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import ContractBase from "./contracts/ContractBase"
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import { Instantiable, InstantiableConfig } from "../Instantiable.abstract"
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export class EventHandler extends Instantiable {
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private events = new Set<(blockNumber) => void>()
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private lastBlock: number
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private interval = 200
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private polling: boolean = false
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private lastTimeout: NodeJS.Timeout
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get count() {
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return this.events.size
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}
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constructor(config: InstantiableConfig) {
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super()
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this.setInstanceConfig(config)
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}
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private async checkBlock(isInterval?: boolean, n = 0) {
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const blockNumber = await this.web3.eth.getBlockNumber()
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if ((this.polling && !isInterval) || !this.count) {
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return
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}
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this.polling = true
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if (!this.lastBlock) {
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this.lastBlock = blockNumber
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}
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if (this.lastBlock !== blockNumber) {
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this.events.forEach(fn => fn(this.lastBlock + 1))
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this.lastBlock = blockNumber
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}
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this.lastTimeout = setTimeout(() => this.checkBlock(true, n++), this.interval)
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}
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public subscribe(callback: (number) => void) {
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this.events.add(callback)
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this.checkBlock()
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return {
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unsubscribe: () => this.unsubscribe(callback),
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}
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}
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public unsubscribe(callback: (number) => void) {
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this.events.delete(callback)
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if (!this.count) {
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clearTimeout(this.lastTimeout)
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delete this.lastBlock
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this.polling = false
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}
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}
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public getEvent(contract: ContractBase, eventName: string, filter: {[key: string]: any}) {
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return new ContractEvent(this, contract, eventName, filter)
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}
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}
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