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- var fs = require('graceful-fs')
- var Writable = require('readable-stream').Writable
- var util = require('util')
- var MurmurHash3 = require('imurmurhash')
- var iferr = require('iferr')
- var crypto = require('crypto')
- function murmurhex () {
- var hash = MurmurHash3('')
- for (var ii = 0; ii < arguments.length; ++ii) {
- hash.hash('' + arguments[ii])
- }
- return hash.result()
- }
- var invocations = 0
- function getTmpname (filename) {
- return filename + '.' + murmurhex(__filename, process.pid, ++invocations)
- }
- var setImmediate = global.setImmediate || setTimeout
- module.exports = WriteStreamAtomic
- util.inherits(WriteStreamAtomic, Writable)
- function WriteStreamAtomic (path, options) {
- if (!(this instanceof WriteStreamAtomic)) {
- return new WriteStreamAtomic(path, options)
- }
- Writable.call(this, options)
- this.__isWin = options && options.hasOwnProperty('isWin') ? options.isWin : process.platform === 'win32'
- this.__atomicTarget = path
- this.__atomicTmp = getTmpname(path)
- this.__atomicChown = options && options.chown
- this.__atomicClosed = false
- this.__atomicStream = fs.WriteStream(this.__atomicTmp, options)
- this.__atomicStream.once('open', handleOpen(this))
- this.__atomicStream.once('close', handleClose(this))
- this.__atomicStream.once('error', handleError(this))
- }
- WriteStreamAtomic.prototype.emit = function (event) {
- if (event === 'finish') return this.__atomicStream.end()
- return Writable.prototype.emit.apply(this, arguments)
- }
- WriteStreamAtomic.prototype._write = function (buffer, encoding, cb) {
- var flushed = this.__atomicStream.write(buffer, encoding)
- if (flushed) return cb()
- this.__atomicStream.once('drain', cb)
- }
- function handleOpen (writeStream) {
- return function (fd) {
- writeStream.emit('open', fd)
- }
- }
- function handleClose (writeStream) {
- return function () {
- if (writeStream.__atomicClosed) return
- writeStream.__atomicClosed = true
- if (writeStream.__atomicChown) {
- var uid = writeStream.__atomicChown.uid
- var gid = writeStream.__atomicChown.gid
- return fs.chown(writeStream.__atomicTmp, uid, gid, iferr(cleanup, moveIntoPlace))
- } else {
- moveIntoPlace()
- }
- }
- function moveIntoPlace () {
- fs.rename(writeStream.__atomicTmp, writeStream.__atomicTarget, iferr(trapWindowsEPERM, end))
- }
- function trapWindowsEPERM (err) {
- if (writeStream.__isWin &&
- err.syscall && err.syscall === 'rename' &&
- err.code && err.code === 'EPERM'
- ) {
- checkFileHashes(err)
- } else {
- cleanup(err)
- }
- }
- function checkFileHashes (eperm) {
- var inprocess = 2
- var tmpFileHash = crypto.createHash('sha512')
- var targetFileHash = crypto.createHash('sha512')
- fs.createReadStream(writeStream.__atomicTmp)
- .on('data', function (data, enc) { tmpFileHash.update(data, enc) })
- .on('error', fileHashError)
- .on('end', fileHashComplete)
- fs.createReadStream(writeStream.__atomicTarget)
- .on('data', function (data, enc) { targetFileHash.update(data, enc) })
- .on('error', fileHashError)
- .on('end', fileHashComplete)
- function fileHashError () {
- if (inprocess === 0) return
- inprocess = 0
- cleanup(eperm)
- }
- function fileHashComplete () {
- if (inprocess === 0) return
- if (--inprocess) return
- if (tmpFileHash.digest('hex') === targetFileHash.digest('hex')) {
- return cleanup()
- } else {
- return cleanup(eperm)
- }
- }
- }
- function cleanup (err) {
- fs.unlink(writeStream.__atomicTmp, function () {
- if (err) {
- writeStream.emit('error', err)
- writeStream.emit('close')
- } else {
- end()
- }
- })
- }
- function end () {
-
-
- Writable.prototype.emit.call(writeStream, 'finish')
-
-
-
- setImmediate(function () {
- writeStream.emit('close')
- })
- }
- }
- function handleError (writeStream) {
- return function (er) {
- cleanupSync()
- writeStream.emit('error', er)
- writeStream.__atomicClosed = true
- writeStream.emit('close')
- }
- function cleanupSync () {
- try {
- fs.unlinkSync(writeStream.__atomicTmp)
- } finally {
- return
- }
- }
- }
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