mirall-cli / node_modules / hyperswarm / lib / peer-info.js

const { EventEmitter } = require('events')
const b4a = require('b4a')
const unslab = require('unslab')

const MIN_CONNECTION_TIME = 15000

const VERY_LOW_PRIORITY = 0
const LOW_PRIORITY = 1
const NORMAL_PRIORITY = 2
const HIGH_PRIORITY = 3
const VERY_HIGH_PRIORITY = 4

module.exports = class PeerInfo extends EventEmitter {
  constructor({ publicKey, relayAddresses }) {
    super()

    this.publicKey = unslab(publicKey)
    this.relayAddresses = relayAddresses

    this.reconnecting = true
    this.proven = false
    this.connectedTime = -1
    this.disconnectedTime = 0
    this.banned = false
    this.tried = false
    this.explicit = false
    this.waiting = false
    this.forceRelaying = false

    // Set by the Swarm
    this.queued = false
    this.client = false
    this.topics = [] // TODO: remove on next major (check with mafintosh for context)

    this.attempts = 0
    this.priority = NORMAL_PRIORITY

    // Used by shuffled-priority-queue
    this._index = 0

    // Used for flush management
    this._flushTick = 0

    // Used for topic multiplexing
    this._seenTopics = new Set()
  }

  get server() {
    return !this.client
  }

  get prioritized() {
    return this.priority >= NORMAL_PRIORITY
  }

  _getPriority() {
    const peerIsStale = this.tried && !this.proven
    if (peerIsStale || this.attempts > 3) return VERY_LOW_PRIORITY
    if (this.attempts === 3) return LOW_PRIORITY
    if (this.attempts === 2) return HIGH_PRIORITY
    if (this.attempts === 1) return VERY_HIGH_PRIORITY
    return NORMAL_PRIORITY
  }

  _connected() {
    this.proven = true
    this.connectedTime = Date.now()
  }

  _disconnected() {
    this.disconnectedTime = Date.now()
    if (this.connectedTime > -1) {
      if (this.disconnectedTime - this.connectedTime >= MIN_CONNECTION_TIME) this.attempts = 0 // fast retry
      this.connectedTime = -1
    }
    this.attempts++
  }

  _deprioritize() {
    this.attempts = 3
  }

  _reset() {
    this.client = false
    this.proven = false
    this.tried = false
    this.attempts = 0
  }

  _updatePriority() {
    if (this.explicit && this.attempts > 3) this._deprioritize()
    if (this.banned || this.queued || this.attempts > 3) return false
    this.priority = this._getPriority()
    return true
  }

  _topic(topic) {
    const topicString = b4a.toString(topic, 'hex')
    if (this._seenTopics.has(topicString)) return
    this._seenTopics.add(topicString)
    this.topics.push(topic)
    this.emit('topic', topic)
  }

  reconnect(val) {
    this.reconnecting = !!val
  }

  ban(val) {
    this.banned = !!val
  }

  shouldGC() {
    return !(this.banned || this.queued || this.explicit || this.waiting)
  }
}