bsv/lib/workers-result.js

/**
 * WorkersResult
 * =============
 *
 * A response sent back from a worker to the main thread. Contains the "result"
 * of the computation in the form of a buffer, resbuf. If the actual result is
 * an object with a .toFastBuffer method, the object is converted to a buffer
 * using that method. Otherwise it is JSON serialized into a buffer. The result
 * can also be an error, in which case the isError flag is set.
 */
'use strict'

import { Bw } from './bw'
import { Struct } from './struct'

class WorkersResult extends Struct {
  constructor (resbuf, isError, id) {
    super({ resbuf, isError, id })
  }

  fromResult (result, id) {
    if (result.toFastBuffer) {
      this.resbuf = result.toFastBuffer()
    } else if (Buffer.isBuffer(result)) {
      this.resbuf = result
    } else {
      this.resbuf = Buffer.from(JSON.stringify(result))
    }
    this.isError = false
    this.id = id
    return this
  }

  static fromResult (result, id) {
    return new this().fromResult(result, id)
  }

  fromError (error, id) {
    this.resbuf = Buffer.from(JSON.stringify(error.message))
    this.isError = true
    this.id = id
    return this
  }

  toBw (bw) {
    if (!bw) {
      bw = new Bw()
    }
    bw.writeVarIntNum(this.resbuf.length)
    bw.write(this.resbuf)
    bw.writeUInt8(Number(this.isError))
    bw.writeVarIntNum(this.id)
    return bw
  }

  fromBr (br) {
    const resbuflen = br.readVarIntNum()
    this.resbuf = br.read(resbuflen)
    this.isError = Boolean(br.readUInt8())
    this.id = br.readVarIntNum()
    return this
  }
}

export { WorkersResult }