IOTConnect-Web/node_modules/readable-stream/lib/internal/streams/legacy.js
2024-05-09 09:49:52 +08:00

90 lines
2.8 KiB
JavaScript

'use strict'
const { ArrayIsArray, ObjectSetPrototypeOf } = require('../../ours/primordials')
const { EventEmitter: EE } = require('events')
function Stream(opts) {
EE.call(this, opts)
}
ObjectSetPrototypeOf(Stream.prototype, EE.prototype)
ObjectSetPrototypeOf(Stream, EE)
Stream.prototype.pipe = function (dest, options) {
const source = this
function ondata(chunk) {
if (dest.writable && dest.write(chunk) === false && source.pause) {
source.pause()
}
}
source.on('data', ondata)
function ondrain() {
if (source.readable && source.resume) {
source.resume()
}
}
dest.on('drain', ondrain)
// If the 'end' option is not supplied, dest.end() will be called when
// source gets the 'end' or 'close' events. Only dest.end() once.
if (!dest._isStdio && (!options || options.end !== false)) {
source.on('end', onend)
source.on('close', onclose)
}
let didOnEnd = false
function onend() {
if (didOnEnd) return
didOnEnd = true
dest.end()
}
function onclose() {
if (didOnEnd) return
didOnEnd = true
if (typeof dest.destroy === 'function') dest.destroy()
}
// Don't leave dangling pipes when there are errors.
function onerror(er) {
cleanup()
if (EE.listenerCount(this, 'error') === 0) {
this.emit('error', er)
}
}
prependListener(source, 'error', onerror)
prependListener(dest, 'error', onerror)
// Remove all the event listeners that were added.
function cleanup() {
source.removeListener('data', ondata)
dest.removeListener('drain', ondrain)
source.removeListener('end', onend)
source.removeListener('close', onclose)
source.removeListener('error', onerror)
dest.removeListener('error', onerror)
source.removeListener('end', cleanup)
source.removeListener('close', cleanup)
dest.removeListener('close', cleanup)
}
source.on('end', cleanup)
source.on('close', cleanup)
dest.on('close', cleanup)
dest.emit('pipe', source)
// Allow for unix-like usage: A.pipe(B).pipe(C)
return dest
}
function prependListener(emitter, event, fn) {
// Sadly this is not cacheable as some libraries bundle their own
// event emitter implementation with them.
if (typeof emitter.prependListener === 'function') return emitter.prependListener(event, fn)
// This is a hack to make sure that our error handler is attached before any
// userland ones. NEVER DO THIS. This is here only because this code needs
// to continue to work with older versions of Node.js that do not include
// the prependListener() method. The goal is to eventually remove this hack.
if (!emitter._events || !emitter._events[event]) emitter.on(event, fn)
else if (ArrayIsArray(emitter._events[event])) emitter._events[event].unshift(fn)
else emitter._events[event] = [fn, emitter._events[event]]
}
module.exports = {
Stream,
prependListener
}