101 lines
2.8 KiB
JavaScript
101 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
|
|
}
|