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JavaScript

'use strict'
const proc =
typeof process === 'object' && process
? process
: {
stdout: null,
stderr: null,
}
const EE = require('events')
const Stream = require('stream')
const stringdecoder = require('string_decoder')
const SD = stringdecoder.StringDecoder
const EOF = Symbol('EOF')
const MAYBE_EMIT_END = Symbol('maybeEmitEnd')
const EMITTED_END = Symbol('emittedEnd')
const EMITTING_END = Symbol('emittingEnd')
const EMITTED_ERROR = Symbol('emittedError')
const CLOSED = Symbol('closed')
const READ = Symbol('read')
const FLUSH = Symbol('flush')
const FLUSHCHUNK = Symbol('flushChunk')
const ENCODING = Symbol('encoding')
const DECODER = Symbol('decoder')
const FLOWING = Symbol('flowing')
const PAUSED = Symbol('paused')
const RESUME = Symbol('resume')
const BUFFER = Symbol('buffer')
const PIPES = Symbol('pipes')
const BUFFERLENGTH = Symbol('bufferLength')
const BUFFERPUSH = Symbol('bufferPush')
const BUFFERSHIFT = Symbol('bufferShift')
const OBJECTMODE = Symbol('objectMode')
// internal event when stream is destroyed
const DESTROYED = Symbol('destroyed')
// internal event when stream has an error
const ERROR = Symbol('error')
const EMITDATA = Symbol('emitData')
const EMITEND = Symbol('emitEnd')
const EMITEND2 = Symbol('emitEnd2')
const ASYNC = Symbol('async')
const ABORT = Symbol('abort')
const ABORTED = Symbol('aborted')
const SIGNAL = Symbol('signal')
const defer = fn => Promise.resolve().then(fn)
// TODO remove when Node v8 support drops
const doIter = global._MP_NO_ITERATOR_SYMBOLS_ !== '1'
const ASYNCITERATOR =
(doIter && Symbol.asyncIterator) || Symbol('asyncIterator not implemented')
const ITERATOR =
(doIter && Symbol.iterator) || Symbol('iterator not implemented')
// events that mean 'the stream is over'
// these are treated specially, and re-emitted
// if they are listened for after emitting.
const isEndish = ev => ev === 'end' || ev === 'finish' || ev === 'prefinish'
const isArrayBuffer = b =>
b instanceof ArrayBuffer ||
(typeof b === 'object' &&
b.constructor &&
b.constructor.name === 'ArrayBuffer' &&
b.byteLength >= 0)
const isArrayBufferView = b => !Buffer.isBuffer(b) && ArrayBuffer.isView(b)
class Pipe {
constructor(src, dest, opts) {
this.src = src
this.dest = dest
this.opts = opts
this.ondrain = () => src[RESUME]()
dest.on('drain', this.ondrain)
}
unpipe() {
this.dest.removeListener('drain', this.ondrain)
}
// istanbul ignore next - only here for the prototype
proxyErrors() {}
end() {
this.unpipe()
if (this.opts.end) this.dest.end()
}
}
class PipeProxyErrors extends Pipe {
unpipe() {
this.src.removeListener('error', this.proxyErrors)
super.unpipe()
}
constructor(src, dest, opts) {
super(src, dest, opts)
this.proxyErrors = er => dest.emit('error', er)
src.on('error', this.proxyErrors)
}
}
class Minipass extends Stream {
constructor(options) {
super()
this[FLOWING] = false
// whether we're explicitly paused
this[PAUSED] = false
this[PIPES] = []
this[BUFFER] = []
this[OBJECTMODE] = (options && options.objectMode) || false
if (this[OBJECTMODE]) this[ENCODING] = null
else this[ENCODING] = (options && options.encoding) || null
if (this[ENCODING] === 'buffer') this[ENCODING] = null
this[ASYNC] = (options && !!options.async) || false
this[DECODER] = this[ENCODING] ? new SD(this[ENCODING]) : null
this[EOF] = false
this[EMITTED_END] = false
this[EMITTING_END] = false
this[CLOSED] = false
this[EMITTED_ERROR] = null
this.writable = true
this.readable = true
this[BUFFERLENGTH] = 0
this[DESTROYED] = false
if (options && options.debugExposeBuffer === true) {
Object.defineProperty(this, 'buffer', { get: () => this[BUFFER] })
}
if (options && options.debugExposePipes === true) {
Object.defineProperty(this, 'pipes', { get: () => this[PIPES] })
}
this[SIGNAL] = options && options.signal
this[ABORTED] = false
if (this[SIGNAL]) {
this[SIGNAL].addEventListener('abort', () => this[ABORT]())
if (this[SIGNAL].aborted) {
this[ABORT]()
}
}
}
get bufferLength() {
return this[BUFFERLENGTH]
}
get encoding() {
return this[ENCODING]
}
set encoding(enc) {
if (this[OBJECTMODE]) throw new Error('cannot set encoding in objectMode')
if (
this[ENCODING] &&
enc !== this[ENCODING] &&
((this[DECODER] && this[DECODER].lastNeed) || this[BUFFERLENGTH])
)
throw new Error('cannot change encoding')
if (this[ENCODING] !== enc) {
this[DECODER] = enc ? new SD(enc) : null
if (this[BUFFER].length)
this[BUFFER] = this[BUFFER].map(chunk => this[DECODER].write(chunk))
}
this[ENCODING] = enc
}
setEncoding(enc) {
this.encoding = enc
}
get objectMode() {
return this[OBJECTMODE]
}
set objectMode(om) {
this[OBJECTMODE] = this[OBJECTMODE] || !!om
}
get ['async']() {
return this[ASYNC]
}
set ['async'](a) {
this[ASYNC] = this[ASYNC] || !!a
}
// drop everything and get out of the flow completely
[ABORT]() {
this[ABORTED] = true
this.emit('abort', this[SIGNAL].reason)
this.destroy(this[SIGNAL].reason)
}
get aborted() {
return this[ABORTED]
}
set aborted(_) {}
write(chunk, encoding, cb) {
if (this[ABORTED]) return false
if (this[EOF]) throw new Error('write after end')
if (this[DESTROYED]) {
this.emit(
'error',
Object.assign(
new Error('Cannot call write after a stream was destroyed'),
{ code: 'ERR_STREAM_DESTROYED' }
)
)
return true
}
if (typeof encoding === 'function') (cb = encoding), (encoding = 'utf8')
if (!encoding) encoding = 'utf8'
const fn = this[ASYNC] ? defer : f => f()
// convert array buffers and typed array views into buffers
// at some point in the future, we may want to do the opposite!
// leave strings and buffers as-is
// anything else switches us into object mode
if (!this[OBJECTMODE] && !Buffer.isBuffer(chunk)) {
if (isArrayBufferView(chunk))
chunk = Buffer.from(chunk.buffer, chunk.byteOffset, chunk.byteLength)
else if (isArrayBuffer(chunk)) chunk = Buffer.from(chunk)
else if (typeof chunk !== 'string')
// use the setter so we throw if we have encoding set
this.objectMode = true
}
// handle object mode up front, since it's simpler
// this yields better performance, fewer checks later.
if (this[OBJECTMODE]) {
/* istanbul ignore if - maybe impossible? */
if (this.flowing && this[BUFFERLENGTH] !== 0) this[FLUSH](true)
if (this.flowing) this.emit('data', chunk)
else this[BUFFERPUSH](chunk)
if (this[BUFFERLENGTH] !== 0) this.emit('readable')
if (cb) fn(cb)
return this.flowing
}
// at this point the chunk is a buffer or string
// don't buffer it up or send it to the decoder
if (!chunk.length) {
if (this[BUFFERLENGTH] !== 0) this.emit('readable')
if (cb) fn(cb)
return this.flowing
}
// fast-path writing strings of same encoding to a stream with
// an empty buffer, skipping the buffer/decoder dance
if (
typeof chunk === 'string' &&
// unless it is a string already ready for us to use
!(encoding === this[ENCODING] && !this[DECODER].lastNeed)
) {
chunk = Buffer.from(chunk, encoding)
}
if (Buffer.isBuffer(chunk) && this[ENCODING])
chunk = this[DECODER].write(chunk)
// Note: flushing CAN potentially switch us into not-flowing mode
if (this.flowing && this[BUFFERLENGTH] !== 0) this[FLUSH](true)
if (this.flowing) this.emit('data', chunk)
else this[BUFFERPUSH](chunk)
if (this[BUFFERLENGTH] !== 0) this.emit('readable')
if (cb) fn(cb)
return this.flowing
}
read(n) {
if (this[DESTROYED]) return null
if (this[BUFFERLENGTH] === 0 || n === 0 || n > this[BUFFERLENGTH]) {
this[MAYBE_EMIT_END]()
return null
}
if (this[OBJECTMODE]) n = null
if (this[BUFFER].length > 1 && !this[OBJECTMODE]) {
if (this.encoding) this[BUFFER] = [this[BUFFER].join('')]
else this[BUFFER] = [Buffer.concat(this[BUFFER], this[BUFFERLENGTH])]
}
const ret = this[READ](n || null, this[BUFFER][0])
this[MAYBE_EMIT_END]()
return ret
}
[READ](n, chunk) {
if (n === chunk.length || n === null) this[BUFFERSHIFT]()
else {
this[BUFFER][0] = chunk.slice(n)
chunk = chunk.slice(0, n)
this[BUFFERLENGTH] -= n
}
this.emit('data', chunk)
if (!this[BUFFER].length && !this[EOF]) this.emit('drain')
return chunk
}
end(chunk, encoding, cb) {
if (typeof chunk === 'function') (cb = chunk), (chunk = null)
if (typeof encoding === 'function') (cb = encoding), (encoding = 'utf8')
if (chunk) this.write(chunk, encoding)
if (cb) this.once('end', cb)
this[EOF] = true
this.writable = false
// if we haven't written anything, then go ahead and emit,
// even if we're not reading.
// we'll re-emit if a new 'end' listener is added anyway.
// This makes MP more suitable to write-only use cases.
if (this.flowing || !this[PAUSED]) this[MAYBE_EMIT_END]()
return this
}
// don't let the internal resume be overwritten
[RESUME]() {
if (this[DESTROYED]) return
this[PAUSED] = false
this[FLOWING] = true
this.emit('resume')
if (this[BUFFER].length) this[FLUSH]()
else if (this[EOF]) this[MAYBE_EMIT_END]()
else this.emit('drain')
}
resume() {
return this[RESUME]()
}
pause() {
this[FLOWING] = false
this[PAUSED] = true
}
get destroyed() {
return this[DESTROYED]
}
get flowing() {
return this[FLOWING]
}
get paused() {
return this[PAUSED]
}
[BUFFERPUSH](chunk) {
if (this[OBJECTMODE]) this[BUFFERLENGTH] += 1
else this[BUFFERLENGTH] += chunk.length
this[BUFFER].push(chunk)
}
[BUFFERSHIFT]() {
if (this[OBJECTMODE]) this[BUFFERLENGTH] -= 1
else this[BUFFERLENGTH] -= this[BUFFER][0].length
return this[BUFFER].shift()
}
[FLUSH](noDrain) {
do {} while (this[FLUSHCHUNK](this[BUFFERSHIFT]()) && this[BUFFER].length)
if (!noDrain && !this[BUFFER].length && !this[EOF]) this.emit('drain')
}
[FLUSHCHUNK](chunk) {
this.emit('data', chunk)
return this.flowing
}
pipe(dest, opts) {
if (this[DESTROYED]) return
const ended = this[EMITTED_END]
opts = opts || {}
if (dest === proc.stdout || dest === proc.stderr) opts.end = false
else opts.end = opts.end !== false
opts.proxyErrors = !!opts.proxyErrors
// piping an ended stream ends immediately
if (ended) {
if (opts.end) dest.end()
} else {
this[PIPES].push(
!opts.proxyErrors
? new Pipe(this, dest, opts)
: new PipeProxyErrors(this, dest, opts)
)
if (this[ASYNC]) defer(() => this[RESUME]())
else this[RESUME]()
}
return dest
}
unpipe(dest) {
const p = this[PIPES].find(p => p.dest === dest)
if (p) {
this[PIPES].splice(this[PIPES].indexOf(p), 1)
p.unpipe()
}
}
addListener(ev, fn) {
return this.on(ev, fn)
}
on(ev, fn) {
const ret = super.on(ev, fn)
if (ev === 'data' && !this[PIPES].length && !this.flowing) this[RESUME]()
else if (ev === 'readable' && this[BUFFERLENGTH] !== 0)
super.emit('readable')
else if (isEndish(ev) && this[EMITTED_END]) {
super.emit(ev)
this.removeAllListeners(ev)
} else if (ev === 'error' && this[EMITTED_ERROR]) {
if (this[ASYNC]) defer(() => fn.call(this, this[EMITTED_ERROR]))
else fn.call(this, this[EMITTED_ERROR])
}
return ret
}
get emittedEnd() {
return this[EMITTED_END]
}
[MAYBE_EMIT_END]() {
if (
!this[EMITTING_END] &&
!this[EMITTED_END] &&
!this[DESTROYED] &&
this[BUFFER].length === 0 &&
this[EOF]
) {
this[EMITTING_END] = true
this.emit('end')
this.emit('prefinish')
this.emit('finish')
if (this[CLOSED]) this.emit('close')
this[EMITTING_END] = false
}
}
emit(ev, data, ...extra) {
// error and close are only events allowed after calling destroy()
if (ev !== 'error' && ev !== 'close' && ev !== DESTROYED && this[DESTROYED])
return
else if (ev === 'data') {
return !this[OBJECTMODE] && !data
? false
: this[ASYNC]
? defer(() => this[EMITDATA](data))
: this[EMITDATA](data)
} else if (ev === 'end') {
return this[EMITEND]()
} else if (ev === 'close') {
this[CLOSED] = true
// don't emit close before 'end' and 'finish'
if (!this[EMITTED_END] && !this[DESTROYED]) return
const ret = super.emit('close')
this.removeAllListeners('close')
return ret
} else if (ev === 'error') {
this[EMITTED_ERROR] = data
super.emit(ERROR, data)
const ret =
!this[SIGNAL] || this.listeners('error').length
? super.emit('error', data)
: false
this[MAYBE_EMIT_END]()
return ret
} else if (ev === 'resume') {
const ret = super.emit('resume')
this[MAYBE_EMIT_END]()
return ret
} else if (ev === 'finish' || ev === 'prefinish') {
const ret = super.emit(ev)
this.removeAllListeners(ev)
return ret
}
// Some other unknown event
const ret = super.emit(ev, data, ...extra)
this[MAYBE_EMIT_END]()
return ret
}
[EMITDATA](data) {
for (const p of this[PIPES]) {
if (p.dest.write(data) === false) this.pause()
}
const ret = super.emit('data', data)
this[MAYBE_EMIT_END]()
return ret
}
[EMITEND]() {
if (this[EMITTED_END]) return
this[EMITTED_END] = true
this.readable = false
if (this[ASYNC]) defer(() => this[EMITEND2]())
else this[EMITEND2]()
}
[EMITEND2]() {
if (this[DECODER]) {
const data = this[DECODER].end()
if (data) {
for (const p of this[PIPES]) {
p.dest.write(data)
}
super.emit('data', data)
}
}
for (const p of this[PIPES]) {
p.end()
}
const ret = super.emit('end')
this.removeAllListeners('end')
return ret
}
// const all = await stream.collect()
collect() {
const buf = []
if (!this[OBJECTMODE]) buf.dataLength = 0
// set the promise first, in case an error is raised
// by triggering the flow here.
const p = this.promise()
this.on('data', c => {
buf.push(c)
if (!this[OBJECTMODE]) buf.dataLength += c.length
})
return p.then(() => buf)
}
// const data = await stream.concat()
concat() {
return this[OBJECTMODE]
? Promise.reject(new Error('cannot concat in objectMode'))
: this.collect().then(buf =>
this[OBJECTMODE]
? Promise.reject(new Error('cannot concat in objectMode'))
: this[ENCODING]
? buf.join('')
: Buffer.concat(buf, buf.dataLength)
)
}
// stream.promise().then(() => done, er => emitted error)
promise() {
return new Promise((resolve, reject) => {
this.on(DESTROYED, () => reject(new Error('stream destroyed')))
this.on('error', er => reject(er))
this.on('end', () => resolve())
})
}
// for await (let chunk of stream)
[ASYNCITERATOR]() {
let stopped = false
const stop = () => {
this.pause()
stopped = true
return Promise.resolve({ done: true })
}
const next = () => {
if (stopped) return stop()
const res = this.read()
if (res !== null) return Promise.resolve({ done: false, value: res })
if (this[EOF]) return stop()
let resolve = null
let reject = null
const onerr = er => {
this.removeListener('data', ondata)
this.removeListener('end', onend)
this.removeListener(DESTROYED, ondestroy)
stop()
reject(er)
}
const ondata = value => {
this.removeListener('error', onerr)
this.removeListener('end', onend)
this.removeListener(DESTROYED, ondestroy)
this.pause()
resolve({ value: value, done: !!this[EOF] })
}
const onend = () => {
this.removeListener('error', onerr)
this.removeListener('data', ondata)
this.removeListener(DESTROYED, ondestroy)
stop()
resolve({ done: true })
}
const ondestroy = () => onerr(new Error('stream destroyed'))
return new Promise((res, rej) => {
reject = rej
resolve = res
this.once(DESTROYED, ondestroy)
this.once('error', onerr)
this.once('end', onend)
this.once('data', ondata)
})
}
return {
next,
throw: stop,
return: stop,
[ASYNCITERATOR]() {
return this
},
}
}
// for (let chunk of stream)
[ITERATOR]() {
let stopped = false
const stop = () => {
this.pause()
this.removeListener(ERROR, stop)
this.removeListener(DESTROYED, stop)
this.removeListener('end', stop)
stopped = true
return { done: true }
}
const next = () => {
if (stopped) return stop()
const value = this.read()
return value === null ? stop() : { value }
}
this.once('end', stop)
this.once(ERROR, stop)
this.once(DESTROYED, stop)
return {
next,
throw: stop,
return: stop,
[ITERATOR]() {
return this
},
}
}
destroy(er) {
if (this[DESTROYED]) {
if (er) this.emit('error', er)
else this.emit(DESTROYED)
return this
}
this[DESTROYED] = true
// throw away all buffered data, it's never coming out
this[BUFFER].length = 0
this[BUFFERLENGTH] = 0
if (typeof this.close === 'function' && !this[CLOSED]) this.close()
if (er) this.emit('error', er)
// if no error to emit, still reject pending promises
else this.emit(DESTROYED)
return this
}
static isStream(s) {
return (
!!s &&
(s instanceof Minipass ||
s instanceof Stream ||
(s instanceof EE &&
// readable
(typeof s.pipe === 'function' ||
// writable
(typeof s.write === 'function' && typeof s.end === 'function'))))
)
}
}
exports.Minipass = Minipass