560 lines
14 KiB
JavaScript
560 lines
14 KiB
JavaScript
'use strict'
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const proc = typeof process === 'object' && process ? process : {
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stdout: null,
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stderr: null,
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}
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const EE = require('events')
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const Stream = require('stream')
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const Yallist = require('yallist')
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const SD = require('string_decoder').StringDecoder
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const EOF = Symbol('EOF')
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const MAYBE_EMIT_END = Symbol('maybeEmitEnd')
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const EMITTED_END = Symbol('emittedEnd')
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const EMITTING_END = Symbol('emittingEnd')
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const EMITTED_ERROR = Symbol('emittedError')
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const CLOSED = Symbol('closed')
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const READ = Symbol('read')
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const FLUSH = Symbol('flush')
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const FLUSHCHUNK = Symbol('flushChunk')
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const ENCODING = Symbol('encoding')
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const DECODER = Symbol('decoder')
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const FLOWING = Symbol('flowing')
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const PAUSED = Symbol('paused')
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const RESUME = Symbol('resume')
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const BUFFERLENGTH = Symbol('bufferLength')
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const BUFFERPUSH = Symbol('bufferPush')
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const BUFFERSHIFT = Symbol('bufferShift')
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const OBJECTMODE = Symbol('objectMode')
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const DESTROYED = Symbol('destroyed')
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// TODO remove when Node v8 support drops
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const doIter = global._MP_NO_ITERATOR_SYMBOLS_ !== '1'
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const ASYNCITERATOR = doIter && Symbol.asyncIterator
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|| Symbol('asyncIterator not implemented')
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const ITERATOR = doIter && Symbol.iterator
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|| Symbol('iterator not implemented')
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// events that mean 'the stream is over'
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// these are treated specially, and re-emitted
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// if they are listened for after emitting.
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const isEndish = ev =>
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ev === 'end' ||
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ev === 'finish' ||
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ev === 'prefinish'
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const isArrayBuffer = b => b instanceof ArrayBuffer ||
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typeof b === 'object' &&
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b.constructor &&
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b.constructor.name === 'ArrayBuffer' &&
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b.byteLength >= 0
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const isArrayBufferView = b => !Buffer.isBuffer(b) && ArrayBuffer.isView(b)
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module.exports = class Minipass extends Stream {
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constructor (options) {
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super()
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this[FLOWING] = false
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// whether we're explicitly paused
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this[PAUSED] = false
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this.pipes = new Yallist()
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this.buffer = new Yallist()
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this[OBJECTMODE] = options && options.objectMode || false
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if (this[OBJECTMODE])
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this[ENCODING] = null
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else
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this[ENCODING] = options && options.encoding || null
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if (this[ENCODING] === 'buffer')
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this[ENCODING] = null
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this[DECODER] = this[ENCODING] ? new SD(this[ENCODING]) : null
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this[EOF] = false
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this[EMITTED_END] = false
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this[EMITTING_END] = false
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this[CLOSED] = false
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this[EMITTED_ERROR] = null
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this.writable = true
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this.readable = true
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this[BUFFERLENGTH] = 0
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this[DESTROYED] = false
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}
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get bufferLength () { return this[BUFFERLENGTH] }
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get encoding () { return this[ENCODING] }
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set encoding (enc) {
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if (this[OBJECTMODE])
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throw new Error('cannot set encoding in objectMode')
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if (this[ENCODING] && enc !== this[ENCODING] &&
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(this[DECODER] && this[DECODER].lastNeed || this[BUFFERLENGTH]))
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throw new Error('cannot change encoding')
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if (this[ENCODING] !== enc) {
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this[DECODER] = enc ? new SD(enc) : null
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if (this.buffer.length)
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this.buffer = this.buffer.map(chunk => this[DECODER].write(chunk))
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}
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this[ENCODING] = enc
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}
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setEncoding (enc) {
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this.encoding = enc
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}
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get objectMode () { return this[OBJECTMODE] }
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set objectMode (om) { this[OBJECTMODE] = this[OBJECTMODE] || !!om }
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write (chunk, encoding, cb) {
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if (this[EOF])
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throw new Error('write after end')
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if (this[DESTROYED]) {
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this.emit('error', Object.assign(
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new Error('Cannot call write after a stream was destroyed'),
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{ code: 'ERR_STREAM_DESTROYED' }
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))
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return true
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}
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if (typeof encoding === 'function')
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cb = encoding, encoding = 'utf8'
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if (!encoding)
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encoding = 'utf8'
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// convert array buffers and typed array views into buffers
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// at some point in the future, we may want to do the opposite!
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// leave strings and buffers as-is
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// anything else switches us into object mode
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if (!this[OBJECTMODE] && !Buffer.isBuffer(chunk)) {
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if (isArrayBufferView(chunk))
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chunk = Buffer.from(chunk.buffer, chunk.byteOffset, chunk.byteLength)
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else if (isArrayBuffer(chunk))
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chunk = Buffer.from(chunk)
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else if (typeof chunk !== 'string')
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// use the setter so we throw if we have encoding set
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this.objectMode = true
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}
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// this ensures at this point that the chunk is a buffer or string
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// don't buffer it up or send it to the decoder
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if (!this.objectMode && !chunk.length) {
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if (this[BUFFERLENGTH] !== 0)
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this.emit('readable')
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if (cb)
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cb()
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return this.flowing
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}
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// fast-path writing strings of same encoding to a stream with
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// an empty buffer, skipping the buffer/decoder dance
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if (typeof chunk === 'string' && !this[OBJECTMODE] &&
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// unless it is a string already ready for us to use
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!(encoding === this[ENCODING] && !this[DECODER].lastNeed)) {
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chunk = Buffer.from(chunk, encoding)
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}
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if (Buffer.isBuffer(chunk) && this[ENCODING])
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chunk = this[DECODER].write(chunk)
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if (this.flowing) {
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// if we somehow have something in the buffer, but we think we're
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// flowing, then we need to flush all that out first, or we get
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// chunks coming in out of order. Can't emit 'drain' here though,
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// because we're mid-write, so that'd be bad.
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if (this[BUFFERLENGTH] !== 0)
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this[FLUSH](true)
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// if we are still flowing after flushing the buffer we can emit the
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// chunk otherwise we have to buffer it.
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this.flowing
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? this.emit('data', chunk)
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: this[BUFFERPUSH](chunk)
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} else
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this[BUFFERPUSH](chunk)
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if (this[BUFFERLENGTH] !== 0)
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this.emit('readable')
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if (cb)
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cb()
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return this.flowing
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}
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read (n) {
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if (this[DESTROYED])
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return null
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try {
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if (this[BUFFERLENGTH] === 0 || n === 0 || n > this[BUFFERLENGTH])
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return null
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if (this[OBJECTMODE])
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n = null
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if (this.buffer.length > 1 && !this[OBJECTMODE]) {
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if (this.encoding)
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this.buffer = new Yallist([
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Array.from(this.buffer).join('')
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])
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else
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this.buffer = new Yallist([
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Buffer.concat(Array.from(this.buffer), this[BUFFERLENGTH])
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])
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}
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return this[READ](n || null, this.buffer.head.value)
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} finally {
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this[MAYBE_EMIT_END]()
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}
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}
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[READ] (n, chunk) {
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if (n === chunk.length || n === null)
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this[BUFFERSHIFT]()
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else {
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this.buffer.head.value = chunk.slice(n)
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chunk = chunk.slice(0, n)
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this[BUFFERLENGTH] -= n
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}
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this.emit('data', chunk)
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if (!this.buffer.length && !this[EOF])
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this.emit('drain')
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return chunk
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}
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end (chunk, encoding, cb) {
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if (typeof chunk === 'function')
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cb = chunk, chunk = null
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if (typeof encoding === 'function')
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cb = encoding, encoding = 'utf8'
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if (chunk)
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this.write(chunk, encoding)
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if (cb)
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this.once('end', cb)
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this[EOF] = true
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this.writable = false
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// if we haven't written anything, then go ahead and emit,
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// even if we're not reading.
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// we'll re-emit if a new 'end' listener is added anyway.
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// This makes MP more suitable to write-only use cases.
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if (this.flowing || !this[PAUSED])
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this[MAYBE_EMIT_END]()
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return this
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}
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// don't let the internal resume be overwritten
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[RESUME] () {
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if (this[DESTROYED])
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return
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this[PAUSED] = false
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this[FLOWING] = true
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this.emit('resume')
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if (this.buffer.length)
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this[FLUSH]()
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else if (this[EOF])
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this[MAYBE_EMIT_END]()
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else
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this.emit('drain')
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}
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resume () {
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return this[RESUME]()
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}
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pause () {
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this[FLOWING] = false
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this[PAUSED] = true
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}
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get destroyed () {
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return this[DESTROYED]
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}
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get flowing () {
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return this[FLOWING]
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}
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get paused () {
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return this[PAUSED]
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}
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[BUFFERPUSH] (chunk) {
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if (this[OBJECTMODE])
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this[BUFFERLENGTH] += 1
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else
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this[BUFFERLENGTH] += chunk.length
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return this.buffer.push(chunk)
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}
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[BUFFERSHIFT] () {
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if (this.buffer.length) {
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if (this[OBJECTMODE])
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this[BUFFERLENGTH] -= 1
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else
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this[BUFFERLENGTH] -= this.buffer.head.value.length
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}
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return this.buffer.shift()
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}
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[FLUSH] (noDrain) {
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do {} while (this[FLUSHCHUNK](this[BUFFERSHIFT]()))
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if (!noDrain && !this.buffer.length && !this[EOF])
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this.emit('drain')
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}
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[FLUSHCHUNK] (chunk) {
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return chunk ? (this.emit('data', chunk), this.flowing) : false
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}
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pipe (dest, opts) {
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if (this[DESTROYED])
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return
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const ended = this[EMITTED_END]
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opts = opts || {}
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if (dest === proc.stdout || dest === proc.stderr)
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opts.end = false
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else
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opts.end = opts.end !== false
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const p = { dest: dest, opts: opts, ondrain: _ => this[RESUME]() }
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this.pipes.push(p)
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dest.on('drain', p.ondrain)
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this[RESUME]()
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// piping an ended stream ends immediately
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if (ended && p.opts.end)
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p.dest.end()
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return dest
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}
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addListener (ev, fn) {
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return this.on(ev, fn)
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}
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on (ev, fn) {
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try {
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return super.on(ev, fn)
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} finally {
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if (ev === 'data' && !this.pipes.length && !this.flowing)
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this[RESUME]()
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else if (isEndish(ev) && this[EMITTED_END]) {
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super.emit(ev)
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this.removeAllListeners(ev)
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} else if (ev === 'error' && this[EMITTED_ERROR]) {
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fn.call(this, this[EMITTED_ERROR])
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}
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}
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}
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get emittedEnd () {
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return this[EMITTED_END]
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}
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[MAYBE_EMIT_END] () {
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if (!this[EMITTING_END] &&
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!this[EMITTED_END] &&
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!this[DESTROYED] &&
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this.buffer.length === 0 &&
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this[EOF]) {
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this[EMITTING_END] = true
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this.emit('end')
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this.emit('prefinish')
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this.emit('finish')
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if (this[CLOSED])
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this.emit('close')
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this[EMITTING_END] = false
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}
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}
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emit (ev, data) {
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// error and close are only events allowed after calling destroy()
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if (ev !== 'error' && ev !== 'close' && ev !== DESTROYED && this[DESTROYED])
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return
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else if (ev === 'data') {
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if (!data)
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return
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if (this.pipes.length)
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this.pipes.forEach(p =>
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p.dest.write(data) === false && this.pause())
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} else if (ev === 'end') {
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// only actual end gets this treatment
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if (this[EMITTED_END] === true)
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return
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this[EMITTED_END] = true
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this.readable = false
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if (this[DECODER]) {
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data = this[DECODER].end()
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if (data) {
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this.pipes.forEach(p => p.dest.write(data))
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super.emit('data', data)
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}
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}
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this.pipes.forEach(p => {
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p.dest.removeListener('drain', p.ondrain)
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if (p.opts.end)
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p.dest.end()
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})
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} else if (ev === 'close') {
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this[CLOSED] = true
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// don't emit close before 'end' and 'finish'
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if (!this[EMITTED_END] && !this[DESTROYED])
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return
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} else if (ev === 'error') {
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this[EMITTED_ERROR] = data
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}
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// TODO: replace with a spread operator when Node v4 support drops
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const args = new Array(arguments.length)
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args[0] = ev
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args[1] = data
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if (arguments.length > 2) {
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for (let i = 2; i < arguments.length; i++) {
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args[i] = arguments[i]
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}
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}
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try {
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return super.emit.apply(this, args)
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} finally {
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if (!isEndish(ev))
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this[MAYBE_EMIT_END]()
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else
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this.removeAllListeners(ev)
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}
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}
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// const all = await stream.collect()
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collect () {
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const buf = []
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if (!this[OBJECTMODE])
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buf.dataLength = 0
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// set the promise first, in case an error is raised
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// by triggering the flow here.
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const p = this.promise()
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this.on('data', c => {
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buf.push(c)
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if (!this[OBJECTMODE])
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buf.dataLength += c.length
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})
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return p.then(() => buf)
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}
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// const data = await stream.concat()
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concat () {
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return this[OBJECTMODE]
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? Promise.reject(new Error('cannot concat in objectMode'))
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: this.collect().then(buf =>
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this[OBJECTMODE]
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? Promise.reject(new Error('cannot concat in objectMode'))
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: this[ENCODING] ? buf.join('') : Buffer.concat(buf, buf.dataLength))
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}
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// stream.promise().then(() => done, er => emitted error)
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promise () {
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return new Promise((resolve, reject) => {
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this.on(DESTROYED, () => reject(new Error('stream destroyed')))
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this.on('error', er => reject(er))
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this.on('end', () => resolve())
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})
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}
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// for await (let chunk of stream)
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[ASYNCITERATOR] () {
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const next = () => {
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const res = this.read()
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if (res !== null)
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return Promise.resolve({ done: false, value: res })
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if (this[EOF])
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return Promise.resolve({ done: true })
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let resolve = null
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let reject = null
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const onerr = er => {
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this.removeListener('data', ondata)
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this.removeListener('end', onend)
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reject(er)
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}
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const ondata = value => {
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this.removeListener('error', onerr)
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this.removeListener('end', onend)
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this.pause()
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resolve({ value: value, done: !!this[EOF] })
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}
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const onend = () => {
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this.removeListener('error', onerr)
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this.removeListener('data', ondata)
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resolve({ done: true })
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}
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const ondestroy = () => onerr(new Error('stream destroyed'))
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return new Promise((res, rej) => {
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reject = rej
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resolve = res
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this.once(DESTROYED, ondestroy)
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this.once('error', onerr)
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this.once('end', onend)
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this.once('data', ondata)
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})
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}
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return { next }
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}
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// for (let chunk of stream)
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[ITERATOR] () {
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const next = () => {
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const value = this.read()
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const done = value === null
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return { value, done }
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}
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return { next }
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}
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destroy (er) {
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if (this[DESTROYED]) {
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if (er)
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this.emit('error', er)
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else
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this.emit(DESTROYED)
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return this
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}
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this[DESTROYED] = true
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// throw away all buffered data, it's never coming out
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this.buffer = new Yallist()
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this[BUFFERLENGTH] = 0
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if (typeof this.close === 'function' && !this[CLOSED])
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this.close()
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if (er)
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this.emit('error', er)
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else // if no error to emit, still reject pending promises
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this.emit(DESTROYED)
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return this
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}
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static isStream (s) {
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return !!s && (s instanceof Minipass || s instanceof Stream ||
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s instanceof EE && (
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typeof s.pipe === 'function' || // readable
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(typeof s.write === 'function' && typeof s.end === 'function') // writable
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))
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}
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}
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