js-mafmt/src/index.js

'use strict'

const multiaddr = require('multiaddr')

/*
 * Valid combinations
 */
const DNS = base('dns')
const IP = or(base('ip4'), base('ip6'))
const TCP = and(IP, base('tcp'))
const UDP = and(IP, base('udp'))
const UTP = and(UDP, base('utp'))

const WebSockets = or(
  and(TCP, base('ws')),
  and(DNS, base('ws'))
)
const HTTP = or(
  and(TCP, base('http')),
  and(DNS),
  and(DNS, base('http'))
)

const WebRTCStar = and(base('libp2p-webrtc-star'), WebSockets, base('ipfs'))
const WebRTCDirect = and(base('libp2p-webrtc-direct'), HTTP)

const Reliable = or(WebSockets, TCP, UTP)

const IPFS = or(
  and(Reliable, base('ipfs')),
  and(WebRTCStar)
)

exports.DNS = DNS
exports.IP = IP
exports.TCP = TCP
exports.UDP = UDP
exports.UTP = UTP
exports.HTTP = HTTP
exports.WebSockets = WebSockets
exports.WebRTCStar = WebRTCStar
exports.WebRTCDirect = WebRTCDirect
exports.Reliable = Reliable
exports.IPFS = IPFS

/*
 * Validation funcs
 */

function and () {
  const args = Array.from(arguments)

  function matches (a) {
    if (typeof a === 'string') {
      a = multiaddr(a)
    }
    let out = partialMatch(a.protoNames())
    if (out === null) {
      return false
    }
    return out.length === 0
  }

  function partialMatch (a) {
    if (a.length < args.length) {
      return null
    }
    args.some(function (arg) {
      a = arg.partialMatch(a)
      if (a === null) {
        return true
      }
    })

    return a
  }

  return {
    input: args,
    matches: matches,
    partialMatch: partialMatch
  }
}

function or () {
  const args = Array.from(arguments)

  function matches (a) {
    if (typeof a === 'string') {
      a = multiaddr(a)
    }
    const out = partialMatch(a.protoNames())
    if (out === null) {
      return false
    }
    return out.length === 0
  }

  function partialMatch (a) {
    let out = null
    args.some(function (arg) {
      const res = arg.partialMatch(a)
      if (res) {
        out = res
        return true
      }
    })

    return out
  }

  const result = {
    toString: function () { return '{ ' + args.join(' ') + ' }' },
    input: args,
    matches: matches,
    partialMatch: partialMatch
  }

  return result
}

function base (n) {
  const name = n
  function matches (a) {
    if (typeof a === 'string') {
      a = multiaddr(a)
    }

    const pnames = a.protoNames()
    if (pnames.length === 1 && pnames[0] === name) {
      return true
    }
    return false
  }

  function partialMatch (protos) {
    if (protos.length === 0) {
      return null
    }

    if (protos[0] === name) {
      return protos.slice(1)
    }
    return null
  }

  return {
    toString: function () { return name },
    matches: matches,
    partialMatch: partialMatch
  }
}