node_modules/npm/node_modules/fstream/lib/proxy-writer.js

// A writer for when we don't know what kind of thing
// the thing is.  That is, it's not explicitly set,
// so we're going to make it whatever the thing already
// is, or "File"
//
// Until then, collect all events.

module.exports = ProxyWriter

var Writer = require('./writer.js')
var getType = require('./get-type.js')
var inherits = require('inherits')
var collect = require('./collect.js')
var fs = require('fs')

inherits(ProxyWriter, Writer)

function ProxyWriter (props) {
  var self = this
  if (!(self instanceof ProxyWriter)) {
    throw new Error('ProxyWriter must be called as constructor.')
  }

  self.props = props
  self._needDrain = false

  Writer.call(self, props)
}

ProxyWriter.prototype._stat = function () {
  var self = this
  var props = self.props
  // stat the thing to see what the proxy should be.
  var stat = props.follow ? 'stat' : 'lstat'

  fs[stat](props.path, function (er, current) {
    var type
    if (er || !current) {
      type = 'File'
    } else {
      type = getType(current)
    }

    props[type] = true
    props.type = self.type = type

    self._old = current
    self._addProxy(Writer(props, current))
  })
}

ProxyWriter.prototype._addProxy = function (proxy) {
  // console.error("~~ set proxy", this.path)
  var self = this
  if (self._proxy) {
    return self.error('proxy already set')
  }

  self._proxy = proxy
  ;[
    'ready',
    'error',
    'close',
    'pipe',
    'drain',
    'warn'
  ].forEach(function (ev) {
    proxy.on(ev, self.emit.bind(self, ev))
  })

  self.emit('proxy', proxy)

  var calls = self._buffer
  calls.forEach(function (c) {
    // console.error("~~ ~~ proxy buffered call", c[0], c[1])
    proxy[c[0]].apply(proxy, c[1])
  })
  self._buffer.length = 0
  if (self._needsDrain) self.emit('drain')
}

ProxyWriter.prototype.add = function (entry) {
  // console.error("~~ proxy add")
  collect(entry)

  if (!this._proxy) {
    this._buffer.push(['add', [entry]])
    this._needDrain = true
    return false
  }
  return this._proxy.add(entry)
}

ProxyWriter.prototype.write = function (c) {
  // console.error('~~ proxy write')
  if (!this._proxy) {
    this._buffer.push(['write', [c]])
    this._needDrain = true
    return false
  }
  return this._proxy.write(c)
}

ProxyWriter.prototype.end = function (c) {
  // console.error('~~ proxy end')
  if (!this._proxy) {
    this._buffer.push(['end', [c]])
    return false
  }
  return this._proxy.end(c)
}