hyper-booking / node_modules / hyperbee / iterators / local.js

module.exports = class LocalBlocksIterator {
  constructor(batch, opts = {}) {
    this.batch = batch
    this.options = opts
    this.gte = 0
    this.lt = 0
    this.limit = typeof opts.limit === 'number' ? opts.limit : -1
  }

  async open() {
    await this.batch.getRoot(false) // does the update dance
    this.gte = gte(this.options, this.batch.version)
    this.lt = lt(this.options, this.batch.version)
  }

  async next() {
    if (this.limit === 0) return null
    if (this.limit > 0) this.limit--

    while (this.gte < this.lt) {
      try {
        return await this.batch.getBlock(this.gte++)
      } catch {
        continue
      }
    }

    return null
  }

  close() {
    return this.batch._closeSnapshot()
  }
}

function gte(opts, version) {
  if (opts.gt) return (opts.gt < 0 ? opts.gt + version : opts.gt) + 1
  const gte = opts.gte || opts.since || 1
  return gte < 0 ? gte + version : gte
}

function lt(opts, version) {
  if (opts.lte === 0 || opts.lt === 0 || opts.end === 0) return 0
  if (opts.lte) return (opts.lte < 0 ? opts.lte + version : opts.lte) + 1
  const lt = opts.lt || opts.end || version
  return lt < 0 ? lt + version : lt
}