audiobookshelf/server/libs/archiver/archiverUtils/readableStream/internal/streams/duplex.js

// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
// a duplex stream is just a stream that is both readable and writable.
// Since JS doesn't have multiple prototype inheritance, this class
// prototypically inherits from Readable, and then parasitically from
// Writable.
'use strict'

const {
  ObjectDefineProperties,
  ObjectGetOwnPropertyDescriptor,
  ObjectKeys,
  ObjectSetPrototypeOf
} = require('../../ours/primordials')

module.exports = Duplex

const Readable = require('./readable')

const Writable = require('./writable')

ObjectSetPrototypeOf(Duplex.prototype, Readable.prototype)
ObjectSetPrototypeOf(Duplex, Readable)
{
  const keys = ObjectKeys(Writable.prototype) // Allow the keys array to be GC'ed.

  for (let i = 0; i < keys.length; i++) {
    const method = keys[i]
    if (!Duplex.prototype[method]) Duplex.prototype[method] = Writable.prototype[method]
  }
}

function Duplex(options) {
  if (!(this instanceof Duplex)) return new Duplex(options)
  Readable.call(this, options)
  Writable.call(this, options)

  if (options) {
    this.allowHalfOpen = options.allowHalfOpen !== false

    if (options.readable === false) {
      this._readableState.readable = false
      this._readableState.ended = true
      this._readableState.endEmitted = true
    }

    if (options.writable === false) {
      this._writableState.writable = false
      this._writableState.ending = true
      this._writableState.ended = true
      this._writableState.finished = true
    }
  } else {
    this.allowHalfOpen = true
  }
}

ObjectDefineProperties(Duplex.prototype, {
  writable: ObjectGetOwnPropertyDescriptor(Writable.prototype, 'writable'),
  writableHighWaterMark: ObjectGetOwnPropertyDescriptor(Writable.prototype, 'writableHighWaterMark'),
  writableObjectMode: ObjectGetOwnPropertyDescriptor(Writable.prototype, 'writableObjectMode'),
  writableBuffer: ObjectGetOwnPropertyDescriptor(Writable.prototype, 'writableBuffer'),
  writableLength: ObjectGetOwnPropertyDescriptor(Writable.prototype, 'writableLength'),
  writableFinished: ObjectGetOwnPropertyDescriptor(Writable.prototype, 'writableFinished'),
  writableCorked: ObjectGetOwnPropertyDescriptor(Writable.prototype, 'writableCorked'),
  writableEnded: ObjectGetOwnPropertyDescriptor(Writable.prototype, 'writableEnded'),
  writableNeedDrain: ObjectGetOwnPropertyDescriptor(Writable.prototype, 'writableNeedDrain'),
  destroyed: {
    get() {
      if (this._readableState === undefined || this._writableState === undefined) {
        return false
      }

      return this._readableState.destroyed && this._writableState.destroyed
    },

    set(value) {
      // Backward compatibility, the user is explicitly
      // managing destroyed.
      if (this._readableState && this._writableState) {
        this._readableState.destroyed = value
        this._writableState.destroyed = value
      }
    }
  }
})
let webStreamsAdapters // Lazy to avoid circular references

function lazyWebStreams() {
  if (webStreamsAdapters === undefined) webStreamsAdapters = {}
  return webStreamsAdapters
}

Duplex.fromWeb = function (pair, options) {
  return lazyWebStreams().newStreamDuplexFromReadableWritablePair(pair, options)
}

Duplex.toWeb = function (duplex) {
  return lazyWebStreams().newReadableWritablePairFromDuplex(duplex)
}

let duplexify

Duplex.from = function (body) {
  if (!duplexify) {
    duplexify = require('./duplexify')
  }

  return duplexify(body, 'body')
}