zeronet-common/src/peer/pool-getters.js

Common ZeroNet modules

'use strict'

const EventEmitter = require('events').EventEmitter
const debug = require('debug')
const log = process.env.INTENSE_DEBUG ? debug('zeronet:pool:getters') : () => {}

class Getter extends EventEmitter {
  constructor (pool) {
    super()
    this.peers = []
    this.pool = pool
    this.register = () => {
      log('register %s to %s', this.id || this.tag || '<unknown>', pool.zite || '<main>')
      pool.registerGetter(this)
      delete this.register
    }
  }
  _push (peer) {
    this.peers.push(peer)
    log('adding peer %s to getter:%s', peer.id, this.id || this.tag || '<unknown>')
    this.emit('peer', peer)
  }
  get (cb) {
    if (this.peers.length) {
      return cb(null, this.peers.shift())
    } else {
      this.pool.discover()
      this.once('peer', () => cb(null, this.peers.shift()))
    }
  }
  registerGetter (get) {
    this.peers.forEach(p => get.push(p))
    this.on('peer', p => get.push(p))
  }
  stop () {
    this.push = () => {}
    this.peers = null
  }
}

class OnlineGetter extends Getter {
  constructor (pool) {
    super(pool)
    this.tag = 'online'
    this.register()
  }
  push (peer) {
    if (peer.isOnline) {
      this._push(peer)
    }
  }
}

class OfflineGetter extends Getter {
  constructor (pool) {
    super(pool)
    this.tag = 'offline'
    this.register()
  }
  push (peer) {
    if (!peer.isOnline) {
      this._push(peer)
    }
  }
}

class DiscoveryCandidateGetter extends Getter {
  constructor (pool, addr) {
    super(pool)
    this.tag = 'discovery'
    this.zite = addr
    this.pool.on('online', peer => this.push(peer))
    this.register()
  }
  push (peer) {
    if (!peer.ip && !peer.isSeeding(this.zite) && peer.isOnline) this._push(peer)
  }
}

class MetaGetter extends EventEmitter {
  constructor (getters) {
    super()
    this.glist = getters
    this.gobj = {}
    getters.forEach(g => {
      g.id = g.tag || g.constructor.name
      this.gobj[g.id] = g
      g.on('peer', peer => this.emit('peer', g.id, peer))
    })
  }
  get (cb) {
    const f = this.glist.filter(g => g.peers.length)[0]
    if (f) {
      cb(null, f.id, f.peers.shift())
    } else {
      this.once('peer', id =>
        cb(null, id, this.gobj[id].peers.shift()))
    }
  }
  getSync () {
    const f = this.glist.filter(g => g.peers.length)[0]
    if (f) {
      return [f.id, f.peers.shift()]
    } else {
      return false
    }
  }
  get peers () {
    return this.glist.filter(g => g.peers.length).length
  }
  stop () {
    this.glist.map(g => g.stop())
  }
}

module.exports = {
  Getter,
  OnlineGetter,
  OfflineGetter,
  DiscoveryCandidateGetter,
  MetaGetter
}