74 lines
1.8 KiB
TypeScript
74 lines
1.8 KiB
TypeScript
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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get count() {
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return this.events.size
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}
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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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constructor(config: InstantiableConfig) {
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super()
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this.setInstanceConfig(config)
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}
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public subscribe(callback: (blockNumber: 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: (blockNumber: 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(
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contract: ContractBase,
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eventName: string,
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filter: { [key: string]: any }
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) {
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return new ContractEvent(this, contract, eventName, filter)
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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 = global.setTimeout(
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() => this.checkBlock(true, n++),
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this.interval
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)
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}
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}
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