homework/chat-server/node_modules/tar/lib/write-entry.js

'use strict'
const MiniPass = require('minipass')
const Pax = require('./pax.js')
const Header = require('./header.js')
const ReadEntry = require('./read-entry.js')
const fs = require('fs')
const path = require('path')

const types = require('./types.js')
const maxReadSize = 16 * 1024 * 1024
const PROCESS = Symbol('process')
const FILE = Symbol('file')
const DIRECTORY = Symbol('directory')
const SYMLINK = Symbol('symlink')
const HARDLINK = Symbol('hardlink')
const HEADER = Symbol('header')
const READ = Symbol('read')
const LSTAT = Symbol('lstat')
const ONLSTAT = Symbol('onlstat')
const ONREAD = Symbol('onread')
const ONREADLINK = Symbol('onreadlink')
const OPENFILE = Symbol('openfile')
const ONOPENFILE = Symbol('onopenfile')
const CLOSE = Symbol('close')
const MODE = Symbol('mode')
const warner = require('./warn-mixin.js')
const winchars = require('./winchars.js')

const modeFix = require('./mode-fix.js')

const WriteEntry = warner(class WriteEntry extends MiniPass {
  constructor (p, opt) {
    opt = opt || {}
    super(opt)
    if (typeof p !== 'string')
      throw new TypeError('path is required')
    this.path = p
    // suppress atime, ctime, uid, gid, uname, gname
    this.portable = !!opt.portable
    // until node has builtin pwnam functions, this'll have to do
    this.myuid = process.getuid && process.getuid()
    this.myuser = process.env.USER || ''
    this.maxReadSize = opt.maxReadSize || maxReadSize
    this.linkCache = opt.linkCache || new Map()
    this.statCache = opt.statCache || new Map()
    this.preservePaths = !!opt.preservePaths
    this.cwd = opt.cwd || process.cwd()
    this.strict = !!opt.strict
    this.noPax = !!opt.noPax
    this.noMtime = !!opt.noMtime
    this.mtime = opt.mtime || null

    if (typeof opt.onwarn === 'function')
      this.on('warn', opt.onwarn)

    let pathWarn = false
    if (!this.preservePaths && path.win32.isAbsolute(p)) {
      // absolutes on posix are also absolutes on win32
      // so we only need to test this one to get both
      const parsed = path.win32.parse(p)
      this.path = p.substr(parsed.root.length)
      pathWarn = parsed.root
    }

    this.win32 = !!opt.win32 || process.platform === 'win32'
    if (this.win32) {
      this.path = winchars.decode(this.path.replace(/\\/g, '/'))
      p = p.replace(/\\/g, '/')
    }

    this.absolute = opt.absolute || path.resolve(this.cwd, p)

    if (this.path === '')
      this.path = './'

    if (pathWarn) {
      this.warn('TAR_ENTRY_INFO', `stripping ${pathWarn} from absolute path`, {
        entry: this,
        path: pathWarn + this.path,
      })
    }

    if (this.statCache.has(this.absolute))
      this[ONLSTAT](this.statCache.get(this.absolute))
    else
      this[LSTAT]()
  }

  [LSTAT] () {
    fs.lstat(this.absolute, (er, stat) => {
      if (er)
        return this.emit('error', er)
      this[ONLSTAT](stat)
    })
  }

  [ONLSTAT] (stat) {
    this.statCache.set(this.absolute, stat)
    this.stat = stat
    if (!stat.isFile())
      stat.size = 0
    this.type = getType(stat)
    this.emit('stat', stat)
    this[PROCESS]()
  }

  [PROCESS] () {
    switch (this.type) {
      case 'File': return this[FILE]()
      case 'Directory': return this[DIRECTORY]()
      case 'SymbolicLink': return this[SYMLINK]()
      // unsupported types are ignored.
      default: return this.end()
    }
  }

  [MODE] (mode) {
    return modeFix(mode, this.type === 'Directory', this.portable)
  }

  [HEADER] () {
    if (this.type === 'Directory' && this.portable)
      this.noMtime = true

    this.header = new Header({
      path: this.path,
      linkpath: this.linkpath,
      // only the permissions and setuid/setgid/sticky bitflags
      // not the higher-order bits that specify file type
      mode: this[MODE](this.stat.mode),
      uid: this.portable ? null : this.stat.uid,
      gid: this.portable ? null : this.stat.gid,
      size: this.stat.size,
      mtime: this.noMtime ? null : this.mtime || this.stat.mtime,
      type: this.type,
      uname: this.portable ? null :
        this.stat.uid === this.myuid ? this.myuser : '',
      atime: this.portable ? null : this.stat.atime,
      ctime: this.portable ? null : this.stat.ctime
    })

    if (this.header.encode() && !this.noPax)
      this.write(new Pax({
        atime: this.portable ? null : this.header.atime,
        ctime: this.portable ? null : this.header.ctime,
        gid: this.portable ? null : this.header.gid,
        mtime: this.noMtime ? null : this.mtime || this.header.mtime,
        path: this.path,
        linkpath: this.linkpath,
        size: this.header.size,
        uid: this.portable ? null : this.header.uid,
        uname: this.portable ? null : this.header.uname,
        dev: this.portable ? null : this.stat.dev,
        ino: this.portable ? null : this.stat.ino,
        nlink: this.portable ? null : this.stat.nlink
      }).encode())
    this.write(this.header.block)
  }

  [DIRECTORY] () {
    if (this.path.substr(-1) !== '/')
      this.path += '/'
    this.stat.size = 0
    this[HEADER]()
    this.end()
  }

  [SYMLINK] () {
    fs.readlink(this.absolute, (er, linkpath) => {
      if (er)
        return this.emit('error', er)
      this[ONREADLINK](linkpath)
    })
  }

  [ONREADLINK] (linkpath) {
    this.linkpath = linkpath.replace(/\\/g, '/')
    this[HEADER]()
    this.end()
  }

  [HARDLINK] (linkpath) {
    this.type = 'Link'
    this.linkpath = path.relative(this.cwd, linkpath).replace(/\\/g, '/')
    this.stat.size = 0
    this[HEADER]()
    this.end()
  }

  [FILE] () {
    if (this.stat.nlink > 1) {
      const linkKey = this.stat.dev + ':' + this.stat.ino
      if (this.linkCache.has(linkKey)) {
        const linkpath = this.linkCache.get(linkKey)
        if (linkpath.indexOf(this.cwd) === 0)
          return this[HARDLINK](linkpath)
      }
      this.linkCache.set(linkKey, this.absolute)
    }

    this[HEADER]()
    if (this.stat.size === 0)
      return this.end()

    this[OPENFILE]()
  }

  [OPENFILE] () {
    fs.open(this.absolute, 'r', (er, fd) => {
      if (er)
        return this.emit('error', er)
      this[ONOPENFILE](fd)
    })
  }

  [ONOPENFILE] (fd) {
    const blockLen = 512 * Math.ceil(this.stat.size / 512)
    const bufLen = Math.min(blockLen, this.maxReadSize)
    const buf = Buffer.allocUnsafe(bufLen)
    this[READ](fd, buf, 0, buf.length, 0, this.stat.size, blockLen)
  }

  [READ] (fd, buf, offset, length, pos, remain, blockRemain) {
    fs.read(fd, buf, offset, length, pos, (er, bytesRead) => {
      if (er) {
        // ignoring the error from close(2) is a bad practice, but at
        // this point we already have an error, don't need another one
        return this[CLOSE](fd, () => this.emit('error', er))
      }
      this[ONREAD](fd, buf, offset, length, pos, remain, blockRemain, bytesRead)
    })
  }

  [CLOSE] (fd, cb) {
    fs.close(fd, cb)
  }

  [ONREAD] (fd, buf, offset, length, pos, remain, blockRemain, bytesRead) {
    if (bytesRead <= 0 && remain > 0) {
      const er = new Error('encountered unexpected EOF')
      er.path = this.absolute
      er.syscall = 'read'
      er.code = 'EOF'
      return this[CLOSE](fd, () => this.emit('error', er))
    }

    if (bytesRead > remain) {
      const er = new Error('did not encounter expected EOF')
      er.path = this.absolute
      er.syscall = 'read'
      er.code = 'EOF'
      return this[CLOSE](fd, () => this.emit('error', er))
    }

    // null out the rest of the buffer, if we could fit the block padding
    if (bytesRead === remain) {
      for (let i = bytesRead; i < length && bytesRead < blockRemain; i++) {
        buf[i + offset] = 0
        bytesRead ++
        remain ++
      }
    }

    const writeBuf = offset === 0 && bytesRead === buf.length ?
      buf : buf.slice(offset, offset + bytesRead)
    remain -= bytesRead
    blockRemain -= bytesRead
    pos += bytesRead
    offset += bytesRead

    this.write(writeBuf)

    if (!remain) {
      if (blockRemain)
        this.write(Buffer.alloc(blockRemain))
      return this[CLOSE](fd, er => er ? this.emit('error', er) : this.end())
    }

    if (offset >= length) {
      buf = Buffer.allocUnsafe(length)
      offset = 0
    }
    length = buf.length - offset
    this[READ](fd, buf, offset, length, pos, remain, blockRemain)
  }
})

class WriteEntrySync extends WriteEntry {
  constructor (path, opt) {
    super(path, opt)
  }

  [LSTAT] () {
    this[ONLSTAT](fs.lstatSync(this.absolute))
  }

  [SYMLINK] () {
    this[ONREADLINK](fs.readlinkSync(this.absolute))
  }

  [OPENFILE] () {
    this[ONOPENFILE](fs.openSync(this.absolute, 'r'))
  }

  [READ] (fd, buf, offset, length, pos, remain, blockRemain) {
    let threw = true
    try {
      const bytesRead = fs.readSync(fd, buf, offset, length, pos)
      this[ONREAD](fd, buf, offset, length, pos, remain, blockRemain, bytesRead)
      threw = false
    } finally {
      // ignoring the error from close(2) is a bad practice, but at
      // this point we already have an error, don't need another one
      if (threw)
        try { this[CLOSE](fd, () => {}) } catch (er) {}
    }
  }

  [CLOSE] (fd, cb) {
    fs.closeSync(fd)
    cb()
  }
}

const WriteEntryTar = warner(class WriteEntryTar extends MiniPass {
  constructor (readEntry, opt) {
    opt = opt || {}
    super(opt)
    this.preservePaths = !!opt.preservePaths
    this.portable = !!opt.portable
    this.strict = !!opt.strict
    this.noPax = !!opt.noPax
    this.noMtime = !!opt.noMtime

    this.readEntry = readEntry
    this.type = readEntry.type
    if (this.type === 'Directory' && this.portable)
      this.noMtime = true

    this.path = readEntry.path
    this.mode = this[MODE](readEntry.mode)
    this.uid = this.portable ? null : readEntry.uid
    this.gid = this.portable ? null : readEntry.gid
    this.uname = this.portable ? null : readEntry.uname
    this.gname = this.portable ? null : readEntry.gname
    this.size = readEntry.size
    this.mtime = this.noMtime ? null : opt.mtime || readEntry.mtime
    this.atime = this.portable ? null : readEntry.atime
    this.ctime = this.portable ? null : readEntry.ctime
    this.linkpath = readEntry.linkpath

    if (typeof opt.onwarn === 'function')
      this.on('warn', opt.onwarn)

    let pathWarn = false
    if (path.isAbsolute(this.path) && !this.preservePaths) {
      const parsed = path.parse(this.path)
      pathWarn = parsed.root
      this.path = this.path.substr(parsed.root.length)
    }

    this.remain = readEntry.size
    this.blockRemain = readEntry.startBlockSize

    this.header = new Header({
      path: this.path,
      linkpath: this.linkpath,
      // only the permissions and setuid/setgid/sticky bitflags
      // not the higher-order bits that specify file type
      mode: this.mode,
      uid: this.portable ? null : this.uid,
      gid: this.portable ? null : this.gid,
      size: this.size,
      mtime: this.noMtime ? null : this.mtime,
      type: this.type,
      uname: this.portable ? null : this.uname,
      atime: this.portable ? null : this.atime,
      ctime: this.portable ? null : this.ctime
    })

    if (pathWarn) {
      this.warn('TAR_ENTRY_INFO', `stripping ${pathWarn} from absolute path`, {
        entry: this,
        path: pathWarn + this.path,
      })
    }

    if (this.header.encode() && !this.noPax)
      super.write(new Pax({
        atime: this.portable ? null : this.atime,
        ctime: this.portable ? null : this.ctime,
        gid: this.portable ? null : this.gid,
        mtime: this.noMtime ? null : this.mtime,
        path: this.path,
        linkpath: this.linkpath,
        size: this.size,
        uid: this.portable ? null : this.uid,
        uname: this.portable ? null : this.uname,
        dev: this.portable ? null : this.readEntry.dev,
        ino: this.portable ? null : this.readEntry.ino,
        nlink: this.portable ? null : this.readEntry.nlink
      }).encode())

    super.write(this.header.block)
    readEntry.pipe(this)
  }

  [MODE] (mode) {
    return modeFix(mode, this.type === 'Directory', this.portable)
  }

  write (data) {
    const writeLen = data.length
    if (writeLen > this.blockRemain)
      throw new Error('writing more to entry than is appropriate')
    this.blockRemain -= writeLen
    return super.write(data)
  }

  end () {
    if (this.blockRemain)
      this.write(Buffer.alloc(this.blockRemain))
    return super.end()
  }
})

WriteEntry.Sync = WriteEntrySync
WriteEntry.Tar = WriteEntryTar

const getType = stat =>
  stat.isFile() ? 'File'
  : stat.isDirectory() ? 'Directory'
  : stat.isSymbolicLink() ? 'SymbolicLink'
  : 'Unsupported'

module.exports = WriteEntry