387 lines
8.8 KiB
JavaScript
387 lines
8.8 KiB
JavaScript
'use strict'
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const MiniPass = require('minipass')
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const EE = require('events').EventEmitter
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const fs = require('fs')
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// for writev
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const binding = process.binding('fs')
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const writeBuffers = binding.writeBuffers
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const FSReqWrap = binding.FSReqWrap
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const _autoClose = Symbol('_autoClose')
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const _close = Symbol('_close')
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const _ended = Symbol('_ended')
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const _fd = Symbol('_fd')
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const _finished = Symbol('_finished')
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const _flags = Symbol('_flags')
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const _flush = Symbol('_flush')
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const _handleChunk = Symbol('_handleChunk')
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const _makeBuf = Symbol('_makeBuf')
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const _mode = Symbol('_mode')
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const _needDrain = Symbol('_needDrain')
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const _onerror = Symbol('_onerror')
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const _onopen = Symbol('_onopen')
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const _onread = Symbol('_onread')
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const _onwrite = Symbol('_onwrite')
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const _open = Symbol('_open')
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const _path = Symbol('_path')
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const _pos = Symbol('_pos')
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const _queue = Symbol('_queue')
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const _read = Symbol('_read')
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const _readSize = Symbol('_readSize')
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const _reading = Symbol('_reading')
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const _remain = Symbol('_remain')
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const _size = Symbol('_size')
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const _write = Symbol('_write')
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const _writing = Symbol('_writing')
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const _defaultFlag = Symbol('_defaultFlag')
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class ReadStream extends MiniPass {
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constructor (path, opt) {
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opt = opt || {}
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super(opt)
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this.writable = false
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if (typeof path !== 'string')
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throw new TypeError('path must be a string')
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this[_fd] = typeof opt.fd === 'number' ? opt.fd : null
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this[_path] = path
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this[_readSize] = opt.readSize || 16*1024*1024
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this[_reading] = false
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this[_size] = typeof opt.size === 'number' ? opt.size : Infinity
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this[_remain] = this[_size]
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this[_autoClose] = typeof opt.autoClose === 'boolean' ?
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opt.autoClose : true
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if (typeof this[_fd] === 'number')
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this[_read]()
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else
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this[_open]()
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}
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get fd () { return this[_fd] }
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get path () { return this[_path] }
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write () {
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throw new TypeError('this is a readable stream')
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}
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end () {
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throw new TypeError('this is a readable stream')
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}
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[_open] () {
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fs.open(this[_path], 'r', (er, fd) => this[_onopen](er, fd))
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}
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[_onopen] (er, fd) {
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if (er)
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this[_onerror](er)
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else {
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this[_fd] = fd
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this.emit('open', fd)
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this[_read]()
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}
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}
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[_makeBuf] () {
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return Buffer.allocUnsafe(Math.min(this[_readSize], this[_remain]))
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}
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[_read] () {
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if (!this[_reading]) {
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this[_reading] = true
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const buf = this[_makeBuf]()
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/* istanbul ignore if */
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if (buf.length === 0) return process.nextTick(() => this[_onread](null, 0, buf))
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fs.read(this[_fd], buf, 0, buf.length, null, (er, br, buf) =>
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this[_onread](er, br, buf))
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}
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}
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[_onread] (er, br, buf) {
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this[_reading] = false
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if (er)
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this[_onerror](er)
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else if (this[_handleChunk](br, buf))
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this[_read]()
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}
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[_close] () {
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if (this[_autoClose] && typeof this[_fd] === 'number') {
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fs.close(this[_fd], _ => this.emit('close'))
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this[_fd] = null
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}
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}
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[_onerror] (er) {
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this[_reading] = true
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this[_close]()
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this.emit('error', er)
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}
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[_handleChunk] (br, buf) {
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let ret = false
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// no effect if infinite
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this[_remain] -= br
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if (br > 0)
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ret = super.write(br < buf.length ? buf.slice(0, br) : buf)
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if (br === 0 || this[_remain] <= 0) {
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ret = false
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this[_close]()
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super.end()
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}
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return ret
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}
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emit (ev, data) {
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switch (ev) {
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case 'prefinish':
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case 'finish':
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break
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case 'drain':
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if (typeof this[_fd] === 'number')
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this[_read]()
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break
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default:
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return super.emit(ev, data)
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}
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}
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}
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class ReadStreamSync extends ReadStream {
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[_open] () {
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let threw = true
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try {
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this[_onopen](null, fs.openSync(this[_path], 'r'))
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threw = false
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} finally {
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if (threw)
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this[_close]()
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}
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}
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[_read] () {
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let threw = true
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try {
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if (!this[_reading]) {
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this[_reading] = true
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do {
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const buf = this[_makeBuf]()
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/* istanbul ignore next */
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const br = buf.length === 0 ? 0 : fs.readSync(this[_fd], buf, 0, buf.length, null)
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if (!this[_handleChunk](br, buf))
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break
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} while (true)
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this[_reading] = false
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}
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threw = false
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} finally {
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if (threw)
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this[_close]()
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}
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}
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[_close] () {
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if (this[_autoClose] && typeof this[_fd] === 'number') {
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try {
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fs.closeSync(this[_fd])
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} catch (er) {}
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this[_fd] = null
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this.emit('close')
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}
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}
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}
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class WriteStream extends EE {
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constructor (path, opt) {
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opt = opt || {}
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super(opt)
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this.readable = false
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this[_writing] = false
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this[_ended] = false
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this[_needDrain] = false
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this[_queue] = []
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this[_path] = path
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this[_fd] = typeof opt.fd === 'number' ? opt.fd : null
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this[_mode] = opt.mode === undefined ? 0o666 : opt.mode
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this[_pos] = typeof opt.start === 'number' ? opt.start : null
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this[_autoClose] = typeof opt.autoClose === 'boolean' ?
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opt.autoClose : true
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// truncating makes no sense when writing into the middle
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const defaultFlag = this[_pos] !== null ? 'r+' : 'w'
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this[_defaultFlag] = opt.flags === undefined
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this[_flags] = this[_defaultFlag] ? defaultFlag : opt.flags
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if (this[_fd] === null)
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this[_open]()
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}
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get fd () { return this[_fd] }
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get path () { return this[_path] }
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[_onerror] (er) {
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this[_close]()
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this[_writing] = true
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this.emit('error', er)
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}
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[_open] () {
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fs.open(this[_path], this[_flags], this[_mode],
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(er, fd) => this[_onopen](er, fd))
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}
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[_onopen] (er, fd) {
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if (this[_defaultFlag] &&
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this[_flags] === 'r+' &&
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er && er.code === 'ENOENT') {
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this[_flags] = 'w'
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this[_open]()
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} else if (er)
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this[_onerror](er)
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else {
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this[_fd] = fd
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this.emit('open', fd)
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this[_flush]()
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}
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}
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end (buf, enc) {
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if (buf)
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this.write(buf, enc)
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this[_ended] = true
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// synthetic after-write logic, where drain/finish live
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if (!this[_writing] && !this[_queue].length &&
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typeof this[_fd] === 'number')
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this[_onwrite](null, 0)
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}
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write (buf, enc) {
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if (typeof buf === 'string')
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buf = new Buffer(buf, enc)
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if (this[_ended]) {
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this.emit('error', new Error('write() after end()'))
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return false
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}
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if (this[_fd] === null || this[_writing] || this[_queue].length) {
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this[_queue].push(buf)
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this[_needDrain] = true
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return false
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}
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this[_writing] = true
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this[_write](buf)
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return true
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}
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[_write] (buf) {
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fs.write(this[_fd], buf, 0, buf.length, this[_pos], (er, bw) =>
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this[_onwrite](er, bw))
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}
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[_onwrite] (er, bw) {
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if (er)
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this[_onerror](er)
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else {
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if (this[_pos] !== null)
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this[_pos] += bw
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if (this[_queue].length)
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this[_flush]()
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else {
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this[_writing] = false
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if (this[_ended] && !this[_finished]) {
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this[_finished] = true
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this[_close]()
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this.emit('finish')
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} else if (this[_needDrain]) {
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this[_needDrain] = false
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this.emit('drain')
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}
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}
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}
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}
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[_flush] () {
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if (this[_queue].length === 0) {
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if (this[_ended])
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this[_onwrite](null, 0)
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} else if (this[_queue].length === 1)
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this[_write](this[_queue].pop())
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else {
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const iovec = this[_queue]
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this[_queue] = []
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writev(this[_fd], iovec, this[_pos],
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(er, bw) => this[_onwrite](er, bw))
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}
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}
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[_close] () {
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if (this[_autoClose] && typeof this[_fd] === 'number') {
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fs.close(this[_fd], _ => this.emit('close'))
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this[_fd] = null
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}
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}
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}
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class WriteStreamSync extends WriteStream {
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[_open] () {
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let fd
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try {
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fd = fs.openSync(this[_path], this[_flags], this[_mode])
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} catch (er) {
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if (this[_defaultFlag] &&
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this[_flags] === 'r+' &&
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er && er.code === 'ENOENT') {
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this[_flags] = 'w'
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return this[_open]()
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} else
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throw er
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}
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this[_onopen](null, fd)
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}
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[_close] () {
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if (this[_autoClose] && typeof this[_fd] === 'number') {
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try {
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fs.closeSync(this[_fd])
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} catch (er) {}
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this[_fd] = null
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this.emit('close')
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}
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}
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[_write] (buf) {
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try {
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this[_onwrite](null,
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fs.writeSync(this[_fd], buf, 0, buf.length, this[_pos]))
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} catch (er) {
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this[_onwrite](er, 0)
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}
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}
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}
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const writev = (fd, iovec, pos, cb) => {
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const done = (er, bw) => cb(er, bw, iovec)
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const req = new FSReqWrap()
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req.oncomplete = done
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binding.writeBuffers(fd, iovec, pos, req)
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}
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exports.ReadStream = ReadStream
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exports.ReadStreamSync = ReadStreamSync
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exports.WriteStream = WriteStream
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exports.WriteStreamSync = WriteStreamSync
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