basant307/AI_Governance_Project

1var constants = require('fs-constants')2var eos = require('end-of-stream')3var inherits = require('inherits')4var alloc = Buffer.alloc5 6var Readable = require('readable-stream').Readable7var Writable = require('readable-stream').Writable8var StringDecoder = require('string_decoder').StringDecoder9 10var headers = require('./headers')11 12var DMODE = parseInt('755', 8)13var FMODE = parseInt('644', 8)14 15var END_OF_TAR = alloc(1024)16 17var noop = function () {}18 19var overflow = function (self, size) {20  size &= 51121  if (size) self.push(END_OF_TAR.slice(0, 512 - size))22}23 24function modeToType (mode) {25  switch (mode & constants.S_IFMT) {26    case constants.S_IFBLK: return 'block-device'27    case constants.S_IFCHR: return 'character-device'28    case constants.S_IFDIR: return 'directory'29    case constants.S_IFIFO: return 'fifo'30    case constants.S_IFLNK: return 'symlink'31  }32 33  return 'file'34}35 36var Sink = function (to) {37  Writable.call(this)38  this.written = 039  this._to = to40  this._destroyed = false41}42 43inherits(Sink, Writable)44 45Sink.prototype._write = function (data, enc, cb) {46  this.written += data.length47  if (this._to.push(data)) return cb()48  this._to._drain = cb49}50 51Sink.prototype.destroy = function () {52  if (this._destroyed) return53  this._destroyed = true54  this.emit('close')55}56 57var LinkSink = function () {58  Writable.call(this)59  this.linkname = ''60  this._decoder = new StringDecoder('utf-8')61  this._destroyed = false62}63 64inherits(LinkSink, Writable)65 66LinkSink.prototype._write = function (data, enc, cb) {67  this.linkname += this._decoder.write(data)68  cb()69}70 71LinkSink.prototype.destroy = function () {72  if (this._destroyed) return73  this._destroyed = true74  this.emit('close')75}76 77var Void = function () {78  Writable.call(this)79  this._destroyed = false80}81 82inherits(Void, Writable)83 84Void.prototype._write = function (data, enc, cb) {85  cb(new Error('No body allowed for this entry'))86}87 88Void.prototype.destroy = function () {89  if (this._destroyed) return90  this._destroyed = true91  this.emit('close')92}93 94var Pack = function (opts) {95  if (!(this instanceof Pack)) return new Pack(opts)96  Readable.call(this, opts)97 98  this._drain = noop99  this._finalized = false100  this._finalizing = false101  this._destroyed = false102  this._stream = null103}104 105inherits(Pack, Readable)106 107Pack.prototype.entry = function (header, buffer, callback) {108  if (this._stream) throw new Error('already piping an entry')109  if (this._finalized || this._destroyed) return110 111  if (typeof buffer === 'function') {112    callback = buffer113    buffer = null114  }115 116  if (!callback) callback = noop117 118  var self = this119 120  if (!header.size || header.type === 'symlink') header.size = 0121  if (!header.type) header.type = modeToType(header.mode)122  if (!header.mode) header.mode = header.type === 'directory' ? DMODE : FMODE123  if (!header.uid) header.uid = 0124  if (!header.gid) header.gid = 0125  if (!header.mtime) header.mtime = new Date()126 127  if (typeof buffer === 'string') buffer = Buffer.from(buffer)128  if (Buffer.isBuffer(buffer)) {129    header.size = buffer.length130    this._encode(header)131    var ok = this.push(buffer)132    overflow(self, header.size)133    if (ok) process.nextTick(callback)134    else this._drain = callback135    return new Void()136  }137 138  if (header.type === 'symlink' && !header.linkname) {139    var linkSink = new LinkSink()140    eos(linkSink, function (err) {141      if (err) { // stream was closed142        self.destroy()143        return callback(err)144      }145 146      header.linkname = linkSink.linkname147      self._encode(header)148      callback()149    })150 151    return linkSink152  }153 154  this._encode(header)155 156  if (header.type !== 'file' && header.type !== 'contiguous-file') {157    process.nextTick(callback)158    return new Void()159  }160 161  var sink = new Sink(this)162 163  this._stream = sink164 165  eos(sink, function (err) {166    self._stream = null167 168    if (err) { // stream was closed169      self.destroy()170      return callback(err)171    }172 173    if (sink.written !== header.size) { // corrupting tar174      self.destroy()175      return callback(new Error('size mismatch'))176    }177 178    overflow(self, header.size)179    if (self._finalizing) self.finalize()180    callback()181  })182 183  return sink184}185 186Pack.prototype.finalize = function () {187  if (this._stream) {188    this._finalizing = true189    return190  }191 192  if (this._finalized) return193  this._finalized = true194  this.push(END_OF_TAR)195  this.push(null)196}197 198Pack.prototype.destroy = function (err) {199  if (this._destroyed) return200  this._destroyed = true201 202  if (err) this.emit('error', err)203  this.emit('close')204  if (this._stream && this._stream.destroy) this._stream.destroy()205}206 207Pack.prototype._encode = function (header) {208  if (!header.pax) {209    var buf = headers.encode(header)210    if (buf) {211      this.push(buf)212      return213    }214  }215  this._encodePax(header)216}217 218Pack.prototype._encodePax = function (header) {219  var paxHeader = headers.encodePax({220    name: header.name,221    linkname: header.linkname,222    pax: header.pax223  })224 225  var newHeader = {226    name: 'PaxHeader',227    mode: header.mode,228    uid: header.uid,229    gid: header.gid,230    size: paxHeader.length,231    mtime: header.mtime,232    type: 'pax-header',233    linkname: header.linkname && 'PaxHeader',234    uname: header.uname,235    gname: header.gname,236    devmajor: header.devmajor,237    devminor: header.devminor238  }239 240  this.push(headers.encode(newHeader))241  this.push(paxHeader)242  overflow(this, paxHeader.length)243 244  newHeader.size = header.size245  newHeader.type = header.type246  this.push(headers.encode(newHeader))247}248 249Pack.prototype._read = function (n) {250  var drain = this._drain251  this._drain = noop252  drain()253}254 255module.exports = Pack256