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'use strict'
const proc = typeof process === 'object' && process ? process : {
stdout: null,
stderr: null,
}
const EE = require('events')
const Stream = require('stream')
const SD = require('string_decoder').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 BUFFERLENGTH = Symbol('bufferLength')
const BUFFERPUSH = Symbol('bufferPush')
const BUFFERSHIFT = Symbol('bufferShift')
const OBJECTMODE = Symbol('objectMode')
const DESTROYED = Symbol('destroyed')
const EMITDATA = Symbol('emitData')
const EMITEND = Symbol('emitEnd')
const EMITEND2 = Symbol('emitEnd2')
const ASYNC = Symbol('async')
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)
}
}
module.exports = 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
}
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 }
write (chunk, encoding, cb) {
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.buffer.length) {
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]()))
if (!noDrain && !this.buffer.length && !this[EOF])
this.emit('drain')
}
[FLUSHCHUNK] (chunk) {
return chunk ? (this.emit('data', chunk), this.flowing) : false
}
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 !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
const ret = super.emit('error', data)
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] () {
const next = () => {
const res = this.read()
if (res !== null)
return Promise.resolve({ done: false, value: res })
if (this[EOF])
return Promise.resolve({ done: true })
let resolve = null
let reject = null
const onerr = er => {
this.removeListener('data', ondata)
this.removeListener('end', onend)
reject(er)
}
const ondata = value => {
this.removeListener('error', onerr)
this.removeListener('end', onend)
this.pause()
resolve({ value: value, done: !!this[EOF] })
}
const onend = () => {
this.removeListener('error', onerr)
this.removeListener('data', ondata)
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 }
}
// for (let chunk of stream)
[ITERATOR] () {
const next = () => {
const value = this.read()
const done = value === null
return { value, done }
}
return { next }
}
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)
else // if no error to emit, still reject pending promises
this.emit(DESTROYED)
return this
}
static isStream (s) {
return !!s && (s instanceof Minipass || s instanceof Stream ||
s instanceof EE && (
typeof s.pipe === 'function' || // readable
(typeof s.write === 'function' && typeof s.end === 'function') // writable
))
}
}