class/class_backend/node_modules/destroy/index.js

/*!
 * destroy
 * Copyright(c) 2014 Jonathan Ong
 * Copyright(c) 2015-2022 Douglas Christopher Wilson
 * MIT Licensed
 */

'use strict'

/**
 * Module dependencies.
 * @private
 */

var EventEmitter = require('events').EventEmitter
var ReadStream = require('fs').ReadStream
var Stream = require('stream')
var Zlib = require('zlib')

/**
 * Module exports.
 * @public
 */

module.exports = destroy

/**
 * Destroy the given stream, and optionally suppress any future `error` events.
 *
 * @param {object} stream
 * @param {boolean} suppress
 * @public
 */

function destroy (stream, suppress) {
  if (isFsReadStream(stream)) {
    destroyReadStream(stream)
  } else if (isZlibStream(stream)) {
    destroyZlibStream(stream)
  } else if (hasDestroy(stream)) {
    stream.destroy()
  }

  if (isEventEmitter(stream) && suppress) {
    stream.removeAllListeners('error')
    stream.addListener('error', noop)
  }

  return stream
}

/**
 * Destroy a ReadStream.
 *
 * @param {object} stream
 * @private
 */

function destroyReadStream (stream) {
  stream.destroy()

  if (typeof stream.close === 'function') {
    // node.js core bug work-around
    stream.on('open', onOpenClose)
  }
}

/**
 * Close a Zlib stream.
 *
 * Zlib streams below Node.js 4.5.5 have a buggy implementation
 * of .close() when zlib encountered an error.
 *
 * @param {object} stream
 * @private
 */

function closeZlibStream (stream) {
  if (stream._hadError === true) {
    var prop = stream._binding === null
      ? '_binding'
      : '_handle'

    stream[prop] = {
      close: function () { this[prop] = null }
    }
  }

  stream.close()
}

/**
 * Destroy a Zlib stream.
 *
 * Zlib streams don't have a destroy function in Node.js 6. On top of that
 * simply calling destroy on a zlib stream in Node.js 8+ will result in a
 * memory leak. So until that is fixed, we need to call both close AND destroy.
 *
 * PR to fix memory leak: https://github.com/nodejs/node/pull/23734
 *
 * In Node.js 6+8, it's important that destroy is called before close as the
 * stream would otherwise emit the error 'zlib binding closed'.
 *
 * @param {object} stream
 * @private
 */

function destroyZlibStream (stream) {
  if (typeof stream.destroy === 'function') {
    // node.js core bug work-around
    // istanbul ignore if: node.js 0.8
    if (stream._binding) {
      // node.js < 0.10.0
      stream.destroy()
      if (stream._processing) {
        stream._needDrain = true
        stream.once('drain', onDrainClearBinding)
      } else {
        stream._binding.clear()
      }
    } else if (stream._destroy && stream._destroy !== Stream.Transform.prototype._destroy) {
      // node.js >= 12, ^11.1.0, ^10.15.1
      stream.destroy()
    } else if (stream._destroy && typeof stream.close === 'function') {
      // node.js 7, 8
      stream.destroyed = true
      stream.close()
    } else {
      // fallback
      // istanbul ignore next
      stream.destroy()
    }
  } else if (typeof stream.close === 'function') {
    // node.js < 8 fallback
    closeZlibStream(stream)
  }
}

/**
 * Determine if stream has destroy.
 * @private
 */

function hasDestroy (stream) {
  return stream instanceof Stream &&
    typeof stream.destroy === 'function'
}

/**
 * Determine if val is EventEmitter.
 * @private
 */

function isEventEmitter (val) {
  return val instanceof EventEmitter
}

/**
 * Determine if stream is fs.ReadStream stream.
 * @private
 */

function isFsReadStream (stream) {
  return stream instanceof ReadStream
}

/**
 * Determine if stream is Zlib stream.
 * @private
 */

function isZlibStream (stream) {
  return stream instanceof Zlib.Gzip ||
    stream instanceof Zlib.Gunzip ||
    stream instanceof Zlib.Deflate ||
    stream instanceof Zlib.DeflateRaw ||
    stream instanceof Zlib.Inflate ||
    stream instanceof Zlib.InflateRaw ||
    stream instanceof Zlib.Unzip
}

/**
 * No-op function.
 * @private
 */

function noop () {}

/**
 * On drain handler to clear binding.
 * @private
 */

// istanbul ignore next: node.js 0.8
function onDrainClearBinding () {
  this._binding.clear()
}

/**
 * On open handler to close stream.
 * @private
 */

function onOpenClose () {
  if (typeof this.fd === 'number') {
    // actually close down the fd
    this.close()
  }
}