!function(e){if("object"==typeof exports&&"undefined"!=typeof module)module.exports=e();else if("function"==typeof define&&define.amd)define([],e);else{var f;"undefined"!=typeof window?f=window:"undefined"!=typeof global?f=global:"undefined"!=typeof self&&(f=self),f.Filer=e()}}(function(){var define,module,exports;return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);throw new Error("Cannot find module '"+o+"'")}var f=n[o]={exports:{}};t[o][0].call(f.exports,function(e){var n=t[o][1][e];return s(n?n:e)},f,f.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(_dereq_,module,exports){
(function (process){
/*global setImmediate: false, setTimeout: false, console: false */

/**
 * async.js shim, based on https://raw.github.com/caolan/async/master/lib/async.js Feb 18, 2014
 * Used under MIT - https://github.com/caolan/async/blob/master/LICENSE
 */

(function () {

    var async = {};

    // async.js functions used in Filer

    //// nextTick implementation with browser-compatible fallback ////
    if (typeof process === 'undefined' || !(process.nextTick)) {
        if (typeof setImmediate === 'function') {
            async.nextTick = function (fn) {
                // not a direct alias for IE10 compatibility
                setImmediate(fn);
            };
            async.setImmediate = async.nextTick;
        }
        else {
            async.nextTick = function (fn) {
                setTimeout(fn, 0);
            };
            async.setImmediate = async.nextTick;
        }
    }
    else {
        async.nextTick = process.nextTick;
        if (typeof setImmediate !== 'undefined') {
            async.setImmediate = function (fn) {
              // not a direct alias for IE10 compatibility
              setImmediate(fn);
            };
        }
        else {
            async.setImmediate = async.nextTick;
        }
    }

    async.eachSeries = function (arr, iterator, callback) {
        callback = callback || function () {};
        if (!arr.length) {
            return callback();
        }
        var completed = 0;
        var iterate = function () {
            iterator(arr[completed], function (err) {
                if (err) {
                    callback(err);
                    callback = function () {};
                }
                else {
                    completed += 1;
                    if (completed >= arr.length) {
                        callback();
                    }
                    else {
                        iterate();
                    }
                }
            });
        };
        iterate();
    };
    async.forEachSeries = async.eachSeries;

    // AMD / RequireJS
    if (typeof define !== 'undefined' && define.amd) {
        define([], function () {
            return async;
        });
    }
    // Node.js
    else if (typeof module !== 'undefined' && module.exports) {
        module.exports = async;
    }
    // included directly via <script> tag
    else {
        root.async = async;
    }

}());

}).call(this,_dereq_("JkpR2F"))
},{"JkpR2F":9}],2:[function(_dereq_,module,exports){
// Based on https://github.com/diy/intercom.js/blob/master/lib/events.js
// Copyright 2012 DIY Co Apache License, Version 2.0
// http://www.apache.org/licenses/LICENSE-2.0

function removeItem(item, array) {
  for (var i = array.length - 1; i >= 0; i--) {
    if (array[i] === item) {
      array.splice(i, 1);
    }
  }
  return array;
}

var EventEmitter = function() {};

EventEmitter.createInterface = function(space) {
  var methods = {};

  methods.on = function(name, fn) {
    if (typeof this[space] === 'undefined') {
      this[space] = {};
    }
    if (!this[space].hasOwnProperty(name)) {
      this[space][name] = [];
    }
    this[space][name].push(fn);
  };

  methods.off = function(name, fn) {
    if (typeof this[space] === 'undefined') return;
    if (this[space].hasOwnProperty(name)) {
      removeItem(fn, this[space][name]);
    }
  };

  methods.trigger = function(name) {
    if (typeof this[space] !== 'undefined' && this[space].hasOwnProperty(name)) {
      var args = Array.prototype.slice.call(arguments, 1);
      for (var i = 0; i < this[space][name].length; i++) {
        this[space][name][i].apply(this[space][name][i], args);
      }
    }
  };

  methods.removeAllListeners = function(name) {
    if (typeof this[space] === 'undefined') return;
    var self = this;
    self[space][name].forEach(function(fn) {
      self.off(name, fn);
    });
  };

  return methods;
};

var pvt = EventEmitter.createInterface('_handlers');
EventEmitter.prototype._on = pvt.on;
EventEmitter.prototype._off = pvt.off;
EventEmitter.prototype._trigger = pvt.trigger;

var pub = EventEmitter.createInterface('handlers');
EventEmitter.prototype.on = function() {
  pub.on.apply(this, arguments);
  Array.prototype.unshift.call(arguments, 'on');
  this._trigger.apply(this, arguments);
};
EventEmitter.prototype.off = pub.off;
EventEmitter.prototype.trigger = pub.trigger;
EventEmitter.prototype.removeAllListeners = pub.removeAllListeners;

module.exports = EventEmitter;

},{}],3:[function(_dereq_,module,exports){
(function (global){
// Based on https://github.com/diy/intercom.js/blob/master/lib/intercom.js
// Copyright 2012 DIY Co Apache License, Version 2.0
// http://www.apache.org/licenses/LICENSE-2.0

var EventEmitter = _dereq_('./eventemitter.js');
var guid = _dereq_('../src/shared.js').guid;

function throttle(delay, fn) {
  var last = 0;
  return function() {
    var now = Date.now();
    if (now - last > delay) {
      last = now;
      fn.apply(this, arguments);
    }
  };
}

function extend(a, b) {
  if (typeof a === 'undefined' || !a) { a = {}; }
  if (typeof b === 'object') {
    for (var key in b) {
      if (b.hasOwnProperty(key)) {
        a[key] = b[key];
      }
    }
  }
  return a;
}

var localStorage = (function(window) {
  if (typeof window === 'undefined' ||
      typeof window.localStorage === 'undefined') {
    return {
      getItem : function() {},
      setItem : function() {},
      removeItem : function() {}
    };
  }
  return window.localStorage;
}(global));

function Intercom() {
  var self = this;
  var now = Date.now();

  this.origin         = guid();
  this.lastMessage    = now;
  this.receivedIDs    = {};
  this.previousValues = {};

  var storageHandler = function() {
    self._onStorageEvent.apply(self, arguments);
  };

  // If we're in node.js, skip event registration
  if (typeof document === 'undefined') {
    return;
  }

  if (document.attachEvent) {
    document.attachEvent('onstorage', storageHandler);
  } else {
    global.addEventListener('storage', storageHandler, false);
  }
}

Intercom.prototype._transaction = function(fn) {
  var TIMEOUT   = 1000;
  var WAIT      = 20;
  var self      = this;
  var executed  = false;
  var listening = false;
  var waitTimer = null;

  function lock() {
    if (executed) {
      return;
    }

    var now = Date.now();
    var activeLock = localStorage.getItem(INDEX_LOCK)|0;
    if (activeLock && now - activeLock < TIMEOUT) {
      if (!listening) {
        self._on('storage', lock);
        listening = true;
      }
      waitTimer = setTimeout(lock, WAIT);
      return;
    }
    executed = true;
    localStorage.setItem(INDEX_LOCK, now);

    fn();
    unlock();
  }

  function unlock() {
    if (listening) {
      self._off('storage', lock);
    }
    if (waitTimer) {
      clearTimeout(waitTimer);
    }
    localStorage.removeItem(INDEX_LOCK);
  }

  lock();
};

Intercom.prototype._cleanup_emit = throttle(100, function() {
  var self = this;

  self._transaction(function() {
    var now = Date.now();
    var threshold = now - THRESHOLD_TTL_EMIT;
    var changed = 0;
    var messages;

    try {
      messages = JSON.parse(localStorage.getItem(INDEX_EMIT) || '[]');
    } catch(e) {
      messages = [];
    }
    for (var i = messages.length - 1; i >= 0; i--) {
      if (messages[i].timestamp < threshold) {
        messages.splice(i, 1);
        changed++;
      }
    }
    if (changed > 0) {
      localStorage.setItem(INDEX_EMIT, JSON.stringify(messages));
    }
  });
});

Intercom.prototype._cleanup_once = throttle(100, function() {
  var self = this;

  self._transaction(function() {
    var timestamp, ttl, key;
    var table;
    var now  = Date.now();
    var changed = 0;

    try {
      table = JSON.parse(localStorage.getItem(INDEX_ONCE) || '{}');
    } catch(e) {
      table = {};
    }
    for (key in table) {
      if (self._once_expired(key, table)) {
        delete table[key];
        changed++;
      }
    }

    if (changed > 0) {
      localStorage.setItem(INDEX_ONCE, JSON.stringify(table));
    }
  });
});

Intercom.prototype._once_expired = function(key, table) {
  if (!table) {
    return true;
  }
  if (!table.hasOwnProperty(key)) {
    return true;
  }
  if (typeof table[key] !== 'object') {
    return true;
  }

  var ttl = table[key].ttl || THRESHOLD_TTL_ONCE;
  var now = Date.now();
  var timestamp = table[key].timestamp;
  return timestamp < now - ttl;
};

Intercom.prototype._localStorageChanged = function(event, field) {
  if (event && event.key) {
    return event.key === field;
  }

  var currentValue = localStorage.getItem(field);
  if (currentValue === this.previousValues[field]) {
    return false;
  }
  this.previousValues[field] = currentValue;
  return true;
};

Intercom.prototype._onStorageEvent = function(event) {
  event = event || global.event;
  var self = this;

  if (this._localStorageChanged(event, INDEX_EMIT)) {
    this._transaction(function() {
      var now = Date.now();
      var data = localStorage.getItem(INDEX_EMIT);
      var messages;

      try {
        messages = JSON.parse(data || '[]');
      } catch(e) {
        messages = [];
      }
      for (var i = 0; i < messages.length; i++) {
        if (messages[i].origin === self.origin) continue;
        if (messages[i].timestamp < self.lastMessage) continue;
        if (messages[i].id) {
          if (self.receivedIDs.hasOwnProperty(messages[i].id)) continue;
          self.receivedIDs[messages[i].id] = true;
        }
        self.trigger(messages[i].name, messages[i].payload);
      }
      self.lastMessage = now;
    });
  }

  this._trigger('storage', event);
};

Intercom.prototype._emit = function(name, message, id) {
  id = (typeof id === 'string' || typeof id === 'number') ? String(id) : null;
  if (id && id.length) {
    if (this.receivedIDs.hasOwnProperty(id)) return;
    this.receivedIDs[id] = true;
  }

  var packet = {
    id        : id,
    name      : name,
    origin    : this.origin,
    timestamp : Date.now(),
    payload   : message
  };

  var self = this;
  this._transaction(function() {
    var data = localStorage.getItem(INDEX_EMIT) || '[]';
    var delimiter = (data === '[]') ? '' : ',';
    data = [data.substring(0, data.length - 1), delimiter, JSON.stringify(packet), ']'].join('');
    localStorage.setItem(INDEX_EMIT, data);
    self.trigger(name, message);

    setTimeout(function() {
      self._cleanup_emit();
    }, 50);
  });
};

Intercom.prototype.emit = function(name, message) {
  this._emit.apply(this, arguments);
  this._trigger('emit', name, message);
};

Intercom.prototype.once = function(key, fn, ttl) {
  if (!Intercom.supported) {
    return;
  }

  var self = this;
  this._transaction(function() {
    var data;
    try {
      data = JSON.parse(localStorage.getItem(INDEX_ONCE) || '{}');
    } catch(e) {
      data = {};
    }
    if (!self._once_expired(key, data)) {
      return;
    }

    data[key] = {};
    data[key].timestamp = Date.now();
    if (typeof ttl === 'number') {
      data[key].ttl = ttl * 1000;
    }

    localStorage.setItem(INDEX_ONCE, JSON.stringify(data));
    fn();

    setTimeout(function() {
      self._cleanup_once();
    }, 50);
  });
};

extend(Intercom.prototype, EventEmitter.prototype);

Intercom.supported = (typeof localStorage !== 'undefined');

var INDEX_EMIT = 'intercom';
var INDEX_ONCE = 'intercom_once';
var INDEX_LOCK = 'intercom_lock';

var THRESHOLD_TTL_EMIT = 50000;
var THRESHOLD_TTL_ONCE = 1000 * 3600;

Intercom.destroy = function() {
  localStorage.removeItem(INDEX_LOCK);
  localStorage.removeItem(INDEX_EMIT);
  localStorage.removeItem(INDEX_ONCE);
};

Intercom.getInstance = (function() {
  var intercom;
  return function() {
    if (!intercom) {
      intercom = new Intercom();
    }
    return intercom;
  };
})();

module.exports = Intercom;

}).call(this,typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"../src/shared.js":26,"./eventemitter.js":2}],4:[function(_dereq_,module,exports){
// Cherry-picked bits of underscore.js, lodash.js

/**
 * Lo-Dash 2.4.0 <http://lodash.com/>
 * Copyright 2012-2013 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.5.2 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <http://lodash.com/license>
 */
var ArrayProto = Array.prototype;
var nativeForEach = ArrayProto.forEach;
var nativeIndexOf = ArrayProto.indexOf;
var nativeSome = ArrayProto.some;

var ObjProto = Object.prototype;
var hasOwnProperty = ObjProto.hasOwnProperty;
var nativeKeys = Object.keys;

var breaker = {};

function has(obj, key) {
  return hasOwnProperty.call(obj, key);
}

var keys = nativeKeys || function(obj) {
  if (obj !== Object(obj)) throw new TypeError('Invalid object');
  var keys = [];
  for (var key in obj) if (has(obj, key)) keys.push(key);
  return keys;
};

function size(obj) {
  if (obj == null) return 0;
  return (obj.length === +obj.length) ? obj.length : keys(obj).length;
}

function identity(value) {
  return value;
}

function each(obj, iterator, context) {
  var i, length;
  if (obj == null) return;
  if (nativeForEach && obj.forEach === nativeForEach) {
    obj.forEach(iterator, context);
  } else if (obj.length === +obj.length) {
    for (i = 0, length = obj.length; i < length; i++) {
      if (iterator.call(context, obj[i], i, obj) === breaker) return;
    }
  } else {
    var keys = keys(obj);
    for (i = 0, length = keys.length; i < length; i++) {
      if (iterator.call(context, obj[keys[i]], keys[i], obj) === breaker) return;
    }
  }
};

function any(obj, iterator, context) {
  iterator || (iterator = identity);
  var result = false;
  if (obj == null) return result;
  if (nativeSome && obj.some === nativeSome) return obj.some(iterator, context);
  each(obj, function(value, index, list) {
    if (result || (result = iterator.call(context, value, index, list))) return breaker;
  });
  return !!result;
};

function contains(obj, target) {
  if (obj == null) return false;
  if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
  return any(obj, function(value) {
    return value === target;
  });
};

function Wrapped(value) {
  this.value = value;
}
Wrapped.prototype.has = function(key) {
  return has(this.value, key);
};
Wrapped.prototype.contains = function(target) {
  return contains(this.value, target);
};
Wrapped.prototype.size = function() {
  return size(this.value);
};

function nodash(value) {
  // don't wrap if already wrapped, even if wrapped by a different `lodash` constructor
  return (value && typeof value == 'object' && !Array.isArray(value) && hasOwnProperty.call(value, '__wrapped__'))
    ? value
    : new Wrapped(value);
}

module.exports = nodash;

},{}],5:[function(_dereq_,module,exports){
/*
 * base64-arraybuffer
 * https://github.com/niklasvh/base64-arraybuffer
 *
 * Copyright (c) 2012 Niklas von Hertzen
 * Licensed under the MIT license.
 */
(function(chars){
  "use strict";

  exports.encode = function(arraybuffer) {
    var bytes = new Uint8Array(arraybuffer),
    i, len = bytes.length, base64 = "";

    for (i = 0; i < len; i+=3) {
      base64 += chars[bytes[i] >> 2];
      base64 += chars[((bytes[i] & 3) << 4) | (bytes[i + 1] >> 4)];
      base64 += chars[((bytes[i + 1] & 15) << 2) | (bytes[i + 2] >> 6)];
      base64 += chars[bytes[i + 2] & 63];
    }

    if ((len % 3) === 2) {
      base64 = base64.substring(0, base64.length - 1) + "=";
    } else if (len % 3 === 1) {
      base64 = base64.substring(0, base64.length - 2) + "==";
    }

    return base64;
  };

  exports.decode =  function(base64) {
    var bufferLength = base64.length * 0.75,
    len = base64.length, i, p = 0,
    encoded1, encoded2, encoded3, encoded4;

    if (base64[base64.length - 1] === "=") {
      bufferLength--;
      if (base64[base64.length - 2] === "=") {
        bufferLength--;
      }
    }

    var arraybuffer = new ArrayBuffer(bufferLength),
    bytes = new Uint8Array(arraybuffer);

    for (i = 0; i < len; i+=4) {
      encoded1 = chars.indexOf(base64[i]);
      encoded2 = chars.indexOf(base64[i+1]);
      encoded3 = chars.indexOf(base64[i+2]);
      encoded4 = chars.indexOf(base64[i+3]);

      bytes[p++] = (encoded1 << 2) | (encoded2 >> 4);
      bytes[p++] = ((encoded2 & 15) << 4) | (encoded3 >> 2);
      bytes[p++] = ((encoded3 & 3) << 6) | (encoded4 & 63);
    }

    return arraybuffer;
  };
})("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/");

},{}],6:[function(_dereq_,module,exports){
/*!
 * The buffer module from node.js, for the browser.
 *
 * @author   Feross Aboukhadijeh <feross@feross.org> <http://feross.org>
 * @license  MIT
 */

var base64 = _dereq_('base64-js')
var ieee754 = _dereq_('ieee754')

exports.Buffer = Buffer
exports.SlowBuffer = Buffer
exports.INSPECT_MAX_BYTES = 50
Buffer.poolSize = 8192

/**
 * If `Buffer._useTypedArrays`:
 *   === true    Use Uint8Array implementation (fastest)
 *   === false   Use Object implementation (compatible down to IE6)
 */
Buffer._useTypedArrays = (function () {
  // Detect if browser supports Typed Arrays. Supported browsers are IE 10+, Firefox 4+,
  // Chrome 7+, Safari 5.1+, Opera 11.6+, iOS 4.2+. If the browser does not support adding
  // properties to `Uint8Array` instances, then that's the same as no `Uint8Array` support
  // because we need to be able to add all the node Buffer API methods. This is an issue
  // in Firefox 4-29. Now fixed: https://bugzilla.mozilla.org/show_bug.cgi?id=695438
  try {
    var buf = new ArrayBuffer(0)
    var arr = new Uint8Array(buf)
    arr.foo = function () { return 42 }
    return 42 === arr.foo() &&
        typeof arr.subarray === 'function' // Chrome 9-10 lack `subarray`
  } catch (e) {
    return false
  }
})()

/**
 * Class: Buffer
 * =============
 *
 * The Buffer constructor returns instances of `Uint8Array` that are augmented
 * with function properties for all the node `Buffer` API functions. We use
 * `Uint8Array` so that square bracket notation works as expected -- it returns
 * a single octet.
 *
 * By augmenting the instances, we can avoid modifying the `Uint8Array`
 * prototype.
 */
function Buffer (subject, encoding, noZero) {
  if (!(this instanceof Buffer))
    return new Buffer(subject, encoding, noZero)

  var type = typeof subject

  if (encoding === 'base64' && type === 'string') {
    subject = base64clean(subject)
  }

  // Find the length
  var length
  if (type === 'number')
    length = coerce(subject)
  else if (type === 'string')
    length = Buffer.byteLength(subject, encoding)
  else if (type === 'object')
    length = coerce(subject.length) // assume that object is array-like
  else
    throw new Error('First argument needs to be a number, array or string.')

  var buf
  if (Buffer._useTypedArrays) {
    // Preferred: Return an augmented `Uint8Array` instance for best performance
    buf = Buffer._augment(new Uint8Array(length))
  } else {
    // Fallback: Return THIS instance of Buffer (created by `new`)
    buf = this
    buf.length = length
    buf._isBuffer = true
  }

  var i
  if (Buffer._useTypedArrays && typeof subject.byteLength === 'number') {
    // Speed optimization -- use set if we're copying from a typed array
    buf._set(subject)
  } else if (isArrayish(subject)) {
    // Treat array-ish objects as a byte array
    if (Buffer.isBuffer(subject)) {
      for (i = 0; i < length; i++)
        buf[i] = subject.readUInt8(i)
    } else {
      for (i = 0; i < length; i++)
        buf[i] = ((subject[i] % 256) + 256) % 256
    }
  } else if (type === 'string') {
    buf.write(subject, 0, encoding)
  } else if (type === 'number' && !Buffer._useTypedArrays && !noZero) {
    for (i = 0; i < length; i++) {
      buf[i] = 0
    }
  }

  return buf
}

// STATIC METHODS
// ==============

Buffer.isEncoding = function (encoding) {
  switch (String(encoding).toLowerCase()) {
    case 'hex':
    case 'utf8':
    case 'utf-8':
    case 'ascii':
    case 'binary':
    case 'base64':
    case 'raw':
    case 'ucs2':
    case 'ucs-2':
    case 'utf16le':
    case 'utf-16le':
      return true
    default:
      return false
  }
}

Buffer.isBuffer = function (b) {
  return !!(b !== null && b !== undefined && b._isBuffer)
}

Buffer.byteLength = function (str, encoding) {
  var ret
  str = str.toString()
  switch (encoding || 'utf8') {
    case 'hex':
      ret = str.length / 2
      break
    case 'utf8':
    case 'utf-8':
      ret = utf8ToBytes(str).length
      break
    case 'ascii':
    case 'binary':
    case 'raw':
      ret = str.length
      break
    case 'base64':
      ret = base64ToBytes(str).length
      break
    case 'ucs2':
    case 'ucs-2':
    case 'utf16le':
    case 'utf-16le':
      ret = str.length * 2
      break
    default:
      throw new Error('Unknown encoding')
  }
  return ret
}

Buffer.concat = function (list, totalLength) {
  assert(isArray(list), 'Usage: Buffer.concat(list[, length])')

  if (list.length === 0) {
    return new Buffer(0)
  } else if (list.length === 1) {
    return list[0]
  }

  var i
  if (totalLength === undefined) {
    totalLength = 0
    for (i = 0; i < list.length; i++) {
      totalLength += list[i].length
    }
  }

  var buf = new Buffer(totalLength)
  var pos = 0
  for (i = 0; i < list.length; i++) {
    var item = list[i]
    item.copy(buf, pos)
    pos += item.length
  }
  return buf
}

Buffer.compare = function (a, b) {
  assert(Buffer.isBuffer(a) && Buffer.isBuffer(b), 'Arguments must be Buffers')
  var x = a.length
  var y = b.length
  for (var i = 0, len = Math.min(x, y); i < len && a[i] === b[i]; i++) {}
  if (i !== len) {
    x = a[i]
    y = b[i]
  }
  if (x < y) {
    return -1
  }
  if (y < x) {
    return 1
  }
  return 0
}

// BUFFER INSTANCE METHODS
// =======================

function hexWrite (buf, string, offset, length) {
  offset = Number(offset) || 0
  var remaining = buf.length - offset
  if (!length) {
    length = remaining
  } else {
    length = Number(length)
    if (length > remaining) {
      length = remaining
    }
  }

  // must be an even number of digits
  var strLen = string.length
  assert(strLen % 2 === 0, 'Invalid hex string')

  if (length > strLen / 2) {
    length = strLen / 2
  }
  for (var i = 0; i < length; i++) {
    var byte = parseInt(string.substr(i * 2, 2), 16)
    assert(!isNaN(byte), 'Invalid hex string')
    buf[offset + i] = byte
  }
  return i
}

function utf8Write (buf, string, offset, length) {
  var charsWritten = blitBuffer(utf8ToBytes(string), buf, offset, length)
  return charsWritten
}

function asciiWrite (buf, string, offset, length) {
  var charsWritten = blitBuffer(asciiToBytes(string), buf, offset, length)
  return charsWritten
}

function binaryWrite (buf, string, offset, length) {
  return asciiWrite(buf, string, offset, length)
}

function base64Write (buf, string, offset, length) {
  var charsWritten = blitBuffer(base64ToBytes(string), buf, offset, length)
  return charsWritten
}

function utf16leWrite (buf, string, offset, length) {
  var charsWritten = blitBuffer(utf16leToBytes(string), buf, offset, length)
  return charsWritten
}

Buffer.prototype.write = function (string, offset, length, encoding) {
  // Support both (string, offset, length, encoding)
  // and the legacy (string, encoding, offset, length)
  if (isFinite(offset)) {
    if (!isFinite(length)) {
      encoding = length
      length = undefined
    }
  } else {  // legacy
    var swap = encoding
    encoding = offset
    offset = length
    length = swap
  }

  offset = Number(offset) || 0
  var remaining = this.length - offset
  if (!length) {
    length = remaining
  } else {
    length = Number(length)
    if (length > remaining) {
      length = remaining
    }
  }
  encoding = String(encoding || 'utf8').toLowerCase()

  var ret
  switch (encoding) {
    case 'hex':
      ret = hexWrite(this, string, offset, length)
      break
    case 'utf8':
    case 'utf-8':
      ret = utf8Write(this, string, offset, length)
      break
    case 'ascii':
      ret = asciiWrite(this, string, offset, length)
      break
    case 'binary':
      ret = binaryWrite(this, string, offset, length)
      break
    case 'base64':
      ret = base64Write(this, string, offset, length)
      break
    case 'ucs2':
    case 'ucs-2':
    case 'utf16le':
    case 'utf-16le':
      ret = utf16leWrite(this, string, offset, length)
      break
    default:
      throw new Error('Unknown encoding')
  }
  return ret
}

Buffer.prototype.toString = function (encoding, start, end) {
  var self = this

  encoding = String(encoding || 'utf8').toLowerCase()
  start = Number(start) || 0
  end = (end === undefined) ? self.length : Number(end)

  // Fastpath empty strings
  if (end === start)
    return ''

  var ret
  switch (encoding) {
    case 'hex':
      ret = hexSlice(self, start, end)
      break
    case 'utf8':
    case 'utf-8':
      ret = utf8Slice(self, start, end)
      break
    case 'ascii':
      ret = asciiSlice(self, start, end)
      break
    case 'binary':
      ret = binarySlice(self, start, end)
      break
    case 'base64':
      ret = base64Slice(self, start, end)
      break
    case 'ucs2':
    case 'ucs-2':
    case 'utf16le':
    case 'utf-16le':
      ret = utf16leSlice(self, start, end)
      break
    default:
      throw new Error('Unknown encoding')
  }
  return ret
}

Buffer.prototype.toJSON = function () {
  return {
    type: 'Buffer',
    data: Array.prototype.slice.call(this._arr || this, 0)
  }
}

Buffer.prototype.equals = function (b) {
  assert(Buffer.isBuffer(b), 'Argument must be a Buffer')
  return Buffer.compare(this, b) === 0
}

Buffer.prototype.compare = function (b) {
  assert(Buffer.isBuffer(b), 'Argument must be a Buffer')
  return Buffer.compare(this, b)
}

// copy(targetBuffer, targetStart=0, sourceStart=0, sourceEnd=buffer.length)
Buffer.prototype.copy = function (target, target_start, start, end) {
  var source = this

  if (!start) start = 0
  if (!end && end !== 0) end = this.length
  if (!target_start) target_start = 0

  // Copy 0 bytes; we're done
  if (end === start) return
  if (target.length === 0 || source.length === 0) return

  // Fatal error conditions
  assert(end >= start, 'sourceEnd < sourceStart')
  assert(target_start >= 0 && target_start < target.length,
      'targetStart out of bounds')
  assert(start >= 0 && start < source.length, 'sourceStart out of bounds')
  assert(end >= 0 && end <= source.length, 'sourceEnd out of bounds')

  // Are we oob?
  if (end > this.length)
    end = this.length
  if (target.length - target_start < end - start)
    end = target.length - target_start + start

  var len = end - start

  if (len < 100 || !Buffer._useTypedArrays) {
    for (var i = 0; i < len; i++) {
      target[i + target_start] = this[i + start]
    }
  } else {
    target._set(this.subarray(start, start + len), target_start)
  }
}

function base64Slice (buf, start, end) {
  if (start === 0 && end === buf.length) {
    return base64.fromByteArray(buf)
  } else {
    return base64.fromByteArray(buf.slice(start, end))
  }
}

function utf8Slice (buf, start, end) {
  var res = ''
  var tmp = ''
  end = Math.min(buf.length, end)

  for (var i = start; i < end; i++) {
    if (buf[i] <= 0x7F) {
      res += decodeUtf8Char(tmp) + String.fromCharCode(buf[i])
      tmp = ''
    } else {
      tmp += '%' + buf[i].toString(16)
    }
  }

  return res + decodeUtf8Char(tmp)
}

function asciiSlice (buf, start, end) {
  var ret = ''
  end = Math.min(buf.length, end)

  for (var i = start; i < end; i++) {
    ret += String.fromCharCode(buf[i])
  }
  return ret
}

function binarySlice (buf, start, end) {
  return asciiSlice(buf, start, end)
}

function hexSlice (buf, start, end) {
  var len = buf.length

  if (!start || start < 0) start = 0
  if (!end || end < 0 || end > len) end = len

  var out = ''
  for (var i = start; i < end; i++) {
    out += toHex(buf[i])
  }
  return out
}

function utf16leSlice (buf, start, end) {
  var bytes = buf.slice(start, end)
  var res = ''
  for (var i = 0; i < bytes.length; i += 2) {
    res += String.fromCharCode(bytes[i] + bytes[i + 1] * 256)
  }
  return res
}

Buffer.prototype.slice = function (start, end) {
  var len = this.length
  start = clamp(start, len, 0)
  end = clamp(end, len, len)

  if (Buffer._useTypedArrays) {
    return Buffer._augment(this.subarray(start, end))
  } else {
    var sliceLen = end - start
    var newBuf = new Buffer(sliceLen, undefined, true)
    for (var i = 0; i < sliceLen; i++) {
      newBuf[i] = this[i + start]
    }
    return newBuf
  }
}

// `get` will be removed in Node 0.13+
Buffer.prototype.get = function (offset) {
  console.log('.get() is deprecated. Access using array indexes instead.')
  return this.readUInt8(offset)
}

// `set` will be removed in Node 0.13+
Buffer.prototype.set = function (v, offset) {
  console.log('.set() is deprecated. Access using array indexes instead.')
  return this.writeUInt8(v, offset)
}

Buffer.prototype.readUInt8 = function (offset, noAssert) {
  if (!noAssert) {
    assert(offset !== undefined && offset !== null, 'missing offset')
    assert(offset < this.length, 'Trying to read beyond buffer length')
  }

  if (offset >= this.length)
    return

  return this[offset]
}

function readUInt16 (buf, offset, littleEndian, noAssert) {
  if (!noAssert) {
    assert(typeof littleEndian === 'boolean', 'missing or invalid endian')
    assert(offset !== undefined && offset !== null, 'missing offset')
    assert(offset + 1 < buf.length, 'Trying to read beyond buffer length')
  }

  var len = buf.length
  if (offset >= len)
    return

  var val
  if (littleEndian) {
    val = buf[offset]
    if (offset + 1 < len)
      val |= buf[offset + 1] << 8
  } else {
    val = buf[offset] << 8
    if (offset + 1 < len)
      val |= buf[offset + 1]
  }
  return val
}

Buffer.prototype.readUInt16LE = function (offset, noAssert) {
  return readUInt16(this, offset, true, noAssert)
}

Buffer.prototype.readUInt16BE = function (offset, noAssert) {
  return readUInt16(this, offset, false, noAssert)
}

function readUInt32 (buf, offset, littleEndian, noAssert) {
  if (!noAssert) {
    assert(typeof littleEndian === 'boolean', 'missing or invalid endian')
    assert(offset !== undefined && offset !== null, 'missing offset')
    assert(offset + 3 < buf.length, 'Trying to read beyond buffer length')
  }

  var len = buf.length
  if (offset >= len)
    return

  var val
  if (littleEndian) {
    if (offset + 2 < len)
      val = buf[offset + 2] << 16
    if (offset + 1 < len)
      val |= buf[offset + 1] << 8
    val |= buf[offset]
    if (offset + 3 < len)
      val = val + (buf[offset + 3] << 24 >>> 0)
  } else {
    if (offset + 1 < len)
      val = buf[offset + 1] << 16
    if (offset + 2 < len)
      val |= buf[offset + 2] << 8
    if (offset + 3 < len)
      val |= buf[offset + 3]
    val = val + (buf[offset] << 24 >>> 0)
  }
  return val
}

Buffer.prototype.readUInt32LE = function (offset, noAssert) {
  return readUInt32(this, offset, true, noAssert)
}

Buffer.prototype.readUInt32BE = function (offset, noAssert) {
  return readUInt32(this, offset, false, noAssert)
}

Buffer.prototype.readInt8 = function (offset, noAssert) {
  if (!noAssert) {
    assert(offset !== undefined && offset !== null,
        'missing offset')
    assert(offset < this.length, 'Trying to read beyond buffer length')
  }

  if (offset >= this.length)
    return

  var neg = this[offset] & 0x80
  if (neg)
    return (0xff - this[offset] + 1) * -1
  else
    return this[offset]
}

function readInt16 (buf, offset, littleEndian, noAssert) {
  if (!noAssert) {
    assert(typeof littleEndian === 'boolean', 'missing or invalid endian')
    assert(offset !== undefined && offset !== null, 'missing offset')
    assert(offset + 1 < buf.length, 'Trying to read beyond buffer length')
  }

  var len = buf.length
  if (offset >= len)
    return

  var val = readUInt16(buf, offset, littleEndian, true)
  var neg = val & 0x8000
  if (neg)
    return (0xffff - val + 1) * -1
  else
    return val
}

Buffer.prototype.readInt16LE = function (offset, noAssert) {
  return readInt16(this, offset, true, noAssert)
}

Buffer.prototype.readInt16BE = function (offset, noAssert) {
  return readInt16(this, offset, false, noAssert)
}

function readInt32 (buf, offset, littleEndian, noAssert) {
  if (!noAssert) {
    assert(typeof littleEndian === 'boolean', 'missing or invalid endian')
    assert(offset !== undefined && offset !== null, 'missing offset')
    assert(offset + 3 < buf.length, 'Trying to read beyond buffer length')
  }

  var len = buf.length
  if (offset >= len)
    return

  var val = readUInt32(buf, offset, littleEndian, true)
  var neg = val & 0x80000000
  if (neg)
    return (0xffffffff - val + 1) * -1
  else
    return val
}

Buffer.prototype.readInt32LE = function (offset, noAssert) {
  return readInt32(this, offset, true, noAssert)
}

Buffer.prototype.readInt32BE = function (offset, noAssert) {
  return readInt32(this, offset, false, noAssert)
}

function readFloat (buf, offset, littleEndian, noAssert) {
  if (!noAssert) {
    assert(typeof littleEndian === 'boolean', 'missing or invalid endian')
    assert(offset + 3 < buf.length, 'Trying to read beyond buffer length')
  }

  return ieee754.read(buf, offset, littleEndian, 23, 4)
}

Buffer.prototype.readFloatLE = function (offset, noAssert) {
  return readFloat(this, offset, true, noAssert)
}

Buffer.prototype.readFloatBE = function (offset, noAssert) {
  return readFloat(this, offset, false, noAssert)
}

function readDouble (buf, offset, littleEndian, noAssert) {
  if (!noAssert) {
    assert(typeof littleEndian === 'boolean', 'missing or invalid endian')
    assert(offset + 7 < buf.length, 'Trying to read beyond buffer length')
  }

  return ieee754.read(buf, offset, littleEndian, 52, 8)
}

Buffer.prototype.readDoubleLE = function (offset, noAssert) {
  return readDouble(this, offset, true, noAssert)
}

Buffer.prototype.readDoubleBE = function (offset, noAssert) {
  return readDouble(this, offset, false, noAssert)
}

Buffer.prototype.writeUInt8 = function (value, offset, noAssert) {
  if (!noAssert) {
    assert(value !== undefined && value !== null, 'missing value')
    assert(offset !== undefined && offset !== null, 'missing offset')
    assert(offset < this.length, 'trying to write beyond buffer length')
    verifuint(value, 0xff)
  }

  if (offset >= this.length) return

  this[offset] = value
  return offset + 1
}

function writeUInt16 (buf, value, offset, littleEndian, noAssert) {
  if (!noAssert) {
    assert(value !== undefined && value !== null, 'missing value')
    assert(typeof littleEndian === 'boolean', 'missing or invalid endian')
    assert(offset !== undefined && offset !== null, 'missing offset')
    assert(offset + 1 < buf.length, 'trying to write beyond buffer length')
    verifuint(value, 0xffff)
  }

  var len = buf.length
  if (offset >= len)
    return

  for (var i = 0, j = Math.min(len - offset, 2); i < j; i++) {
    buf[offset + i] =
        (value & (0xff << (8 * (littleEndian ? i : 1 - i)))) >>>
            (littleEndian ? i : 1 - i) * 8
  }
  return offset + 2
}

Buffer.prototype.writeUInt16LE = function (value, offset, noAssert) {
  return writeUInt16(this, value, offset, true, noAssert)
}

Buffer.prototype.writeUInt16BE = function (value, offset, noAssert) {
  return writeUInt16(this, value, offset, false, noAssert)
}

function writeUInt32 (buf, value, offset, littleEndian, noAssert) {
  if (!noAssert) {
    assert(value !== undefined && value !== null, 'missing value')
    assert(typeof littleEndian === 'boolean', 'missing or invalid endian')
    assert(offset !== undefined && offset !== null, 'missing offset')
    assert(offset + 3 < buf.length, 'trying to write beyond buffer length')
    verifuint(value, 0xffffffff)
  }

  var len = buf.length
  if (offset >= len)
    return

  for (var i = 0, j = Math.min(len - offset, 4); i < j; i++) {
    buf[offset + i] =
        (value >>> (littleEndian ? i : 3 - i) * 8) & 0xff
  }
  return offset + 4
}

Buffer.prototype.writeUInt32LE = function (value, offset, noAssert) {
  return writeUInt32(this, value, offset, true, noAssert)
}

Buffer.prototype.writeUInt32BE = function (value, offset, noAssert) {
  return writeUInt32(this, value, offset, false, noAssert)
}

Buffer.prototype.writeInt8 = function (value, offset, noAssert) {
  if (!noAssert) {
    assert(value !== undefined && value !== null, 'missing value')
    assert(offset !== undefined && offset !== null, 'missing offset')
    assert(offset < this.length, 'Trying to write beyond buffer length')
    verifsint(value, 0x7f, -0x80)
  }

  if (offset >= this.length)
    return

  if (value >= 0)
    this.writeUInt8(value, offset, noAssert)
  else
    this.writeUInt8(0xff + value + 1, offset, noAssert)
  return offset + 1
}

function writeInt16 (buf, value, offset, littleEndian, noAssert) {
  if (!noAssert) {
    assert(value !== undefined && value !== null, 'missing value')
    assert(typeof littleEndian === 'boolean', 'missing or invalid endian')
    assert(offset !== undefined && offset !== null, 'missing offset')
    assert(offset + 1 < buf.length, 'Trying to write beyond buffer length')
    verifsint(value, 0x7fff, -0x8000)
  }

  var len = buf.length
  if (offset >= len)
    return

  if (value >= 0)
    writeUInt16(buf, value, offset, littleEndian, noAssert)
  else
    writeUInt16(buf, 0xffff + value + 1, offset, littleEndian, noAssert)
  return offset + 2
}

Buffer.prototype.writeInt16LE = function (value, offset, noAssert) {
  return writeInt16(this, value, offset, true, noAssert)
}

Buffer.prototype.writeInt16BE = function (value, offset, noAssert) {
  return writeInt16(this, value, offset, false, noAssert)
}

function writeInt32 (buf, value, offset, littleEndian, noAssert) {
  if (!noAssert) {
    assert(value !== undefined && value !== null, 'missing value')
    assert(typeof littleEndian === 'boolean', 'missing or invalid endian')
    assert(offset !== undefined && offset !== null, 'missing offset')
    assert(offset + 3 < buf.length, 'Trying to write beyond buffer length')
    verifsint(value, 0x7fffffff, -0x80000000)
  }

  var len = buf.length
  if (offset >= len)
    return

  if (value >= 0)
    writeUInt32(buf, value, offset, littleEndian, noAssert)
  else
    writeUInt32(buf, 0xffffffff + value + 1, offset, littleEndian, noAssert)
  return offset + 4
}

Buffer.prototype.writeInt32LE = function (value, offset, noAssert) {
  return writeInt32(this, value, offset, true, noAssert)
}

Buffer.prototype.writeInt32BE = function (value, offset, noAssert) {
  return writeInt32(this, value, offset, false, noAssert)
}

function writeFloat (buf, value, offset, littleEndian, noAssert) {
  if (!noAssert) {
    assert(value !== undefined && value !== null, 'missing value')
    assert(typeof littleEndian === 'boolean', 'missing or invalid endian')
    assert(offset !== undefined && offset !== null, 'missing offset')
    assert(offset + 3 < buf.length, 'Trying to write beyond buffer length')
    verifIEEE754(value, 3.4028234663852886e+38, -3.4028234663852886e+38)
  }

  var len = buf.length
  if (offset >= len)
    return

  ieee754.write(buf, value, offset, littleEndian, 23, 4)
  return offset + 4
}

Buffer.prototype.writeFloatLE = function (value, offset, noAssert) {
  return writeFloat(this, value, offset, true, noAssert)
}

Buffer.prototype.writeFloatBE = function (value, offset, noAssert) {
  return writeFloat(this, value, offset, false, noAssert)
}

function writeDouble (buf, value, offset, littleEndian, noAssert) {
  if (!noAssert) {
    assert(value !== undefined && value !== null, 'missing value')
    assert(typeof littleEndian === 'boolean', 'missing or invalid endian')
    assert(offset !== undefined && offset !== null, 'missing offset')
    assert(offset + 7 < buf.length,
        'Trying to write beyond buffer length')
    verifIEEE754(value, 1.7976931348623157E+308, -1.7976931348623157E+308)
  }

  var len = buf.length
  if (offset >= len)
    return

  ieee754.write(buf, value, offset, littleEndian, 52, 8)
  return offset + 8
}

Buffer.prototype.writeDoubleLE = function (value, offset, noAssert) {
  return writeDouble(this, value, offset, true, noAssert)
}

Buffer.prototype.writeDoubleBE = function (value, offset, noAssert) {
  return writeDouble(this, value, offset, false, noAssert)
}

// fill(value, start=0, end=buffer.length)
Buffer.prototype.fill = function (value, start, end) {
  if (!value) value = 0
  if (!start) start = 0
  if (!end) end = this.length

  assert(end >= start, 'end < start')

  // Fill 0 bytes; we're done
  if (end === start) return
  if (this.length === 0) return

  assert(start >= 0 && start < this.length, 'start out of bounds')
  assert(end >= 0 && end <= this.length, 'end out of bounds')

  var i
  if (typeof value === 'number') {
    for (i = start; i < end; i++) {
      this[i] = value
    }
  } else {
    var bytes = utf8ToBytes(value.toString())
    var len = bytes.length
    for (i = start; i < end; i++) {
      this[i] = bytes[i % len]
    }
  }

  return this
}

Buffer.prototype.inspect = function () {
  var out = []
  var len = this.length
  for (var i = 0; i < len; i++) {
    out[i] = toHex(this[i])
    if (i === exports.INSPECT_MAX_BYTES) {
      out[i + 1] = '...'
      break
    }
  }
  return '<Buffer ' + out.join(' ') + '>'
}

/**
 * Creates a new `ArrayBuffer` with the *copied* memory of the buffer instance.
 * Added in Node 0.12. Only available in browsers that support ArrayBuffer.
 */
Buffer.prototype.toArrayBuffer = function () {
  if (typeof Uint8Array !== 'undefined') {
    if (Buffer._useTypedArrays) {
      return (new Buffer(this)).buffer
    } else {
      var buf = new Uint8Array(this.length)
      for (var i = 0, len = buf.length; i < len; i += 1) {
        buf[i] = this[i]
      }
      return buf.buffer
    }
  } else {
    throw new Error('Buffer.toArrayBuffer not supported in this browser')
  }
}

// HELPER FUNCTIONS
// ================

var BP = Buffer.prototype

/**
 * Augment a Uint8Array *instance* (not the Uint8Array class!) with Buffer methods
 */
Buffer._augment = function (arr) {
  arr._isBuffer = true

  // save reference to original Uint8Array get/set methods before overwriting
  arr._get = arr.get
  arr._set = arr.set

  // deprecated, will be removed in node 0.13+
  arr.get = BP.get
  arr.set = BP.set

  arr.write = BP.write
  arr.toString = BP.toString
  arr.toLocaleString = BP.toString
  arr.toJSON = BP.toJSON
  arr.equals = BP.equals
  arr.compare = BP.compare
  arr.copy = BP.copy
  arr.slice = BP.slice
  arr.readUInt8 = BP.readUInt8
  arr.readUInt16LE = BP.readUInt16LE
  arr.readUInt16BE = BP.readUInt16BE
  arr.readUInt32LE = BP.readUInt32LE
  arr.readUInt32BE = BP.readUInt32BE
  arr.readInt8 = BP.readInt8
  arr.readInt16LE = BP.readInt16LE
  arr.readInt16BE = BP.readInt16BE
  arr.readInt32LE = BP.readInt32LE
  arr.readInt32BE = BP.readInt32BE
  arr.readFloatLE = BP.readFloatLE
  arr.readFloatBE = BP.readFloatBE
  arr.readDoubleLE = BP.readDoubleLE
  arr.readDoubleBE = BP.readDoubleBE
  arr.writeUInt8 = BP.writeUInt8
  arr.writeUInt16LE = BP.writeUInt16LE
  arr.writeUInt16BE = BP.writeUInt16BE
  arr.writeUInt32LE = BP.writeUInt32LE
  arr.writeUInt32BE = BP.writeUInt32BE
  arr.writeInt8 = BP.writeInt8
  arr.writeInt16LE = BP.writeInt16LE
  arr.writeInt16BE = BP.writeInt16BE
  arr.writeInt32LE = BP.writeInt32LE
  arr.writeInt32BE = BP.writeInt32BE
  arr.writeFloatLE = BP.writeFloatLE
  arr.writeFloatBE = BP.writeFloatBE
  arr.writeDoubleLE = BP.writeDoubleLE
  arr.writeDoubleBE = BP.writeDoubleBE
  arr.fill = BP.fill
  arr.inspect = BP.inspect
  arr.toArrayBuffer = BP.toArrayBuffer

  return arr
}

var INVALID_BASE64_RE = /[^+\/0-9A-z]/g

function base64clean (str) {
  // Node strips out invalid characters like \n and \t from the string, base64-js does not
  str = stringtrim(str).replace(INVALID_BASE64_RE, '')
  // Node allows for non-padded base64 strings (missing trailing ===), base64-js does not
  while (str.length % 4 !== 0) {
    str = str + '='
  }
  return str
}

function stringtrim (str) {
  if (str.trim) return str.trim()
  return str.replace(/^\s+|\s+$/g, '')
}

// slice(start, end)
function clamp (index, len, defaultValue) {
  if (typeof index !== 'number') return defaultValue
  index = ~~index;  // Coerce to integer.
  if (index >= len) return len
  if (index >= 0) return index
  index += len
  if (index >= 0) return index
  return 0
}

function coerce (length) {
  // Coerce length to a number (possibly NaN), round up
  // in case it's fractional (e.g. 123.456) then do a
  // double negate to coerce a NaN to 0. Easy, right?
  length = ~~Math.ceil(+length)
  return length < 0 ? 0 : length
}

function isArray (subject) {
  return (Array.isArray || function (subject) {
    return Object.prototype.toString.call(subject) === '[object Array]'
  })(subject)
}

function isArrayish (subject) {
  return isArray(subject) || Buffer.isBuffer(subject) ||
      subject && typeof subject === 'object' &&
      typeof subject.length === 'number'
}

function toHex (n) {
  if (n < 16) return '0' + n.toString(16)
  return n.toString(16)
}

function utf8ToBytes (str) {
  var byteArray = []
  for (var i = 0; i < str.length; i++) {
    var b = str.charCodeAt(i)
    if (b <= 0x7F) {
      byteArray.push(b)
    } else {
      var start = i
      if (b >= 0xD800 && b <= 0xDFFF) i++
      var h = encodeURIComponent(str.slice(start, i+1)).substr(1).split('%')
      for (var j = 0; j < h.length; j++) {
        byteArray.push(parseInt(h[j], 16))
      }
    }
  }
  return byteArray
}

function asciiToBytes (str) {
  var byteArray = []
  for (var i = 0; i < str.length; i++) {
    // Node's code seems to be doing this and not & 0x7F..
    byteArray.push(str.charCodeAt(i) & 0xFF)
  }
  return byteArray
}

function utf16leToBytes (str) {
  var c, hi, lo
  var byteArray = []
  for (var i = 0; i < str.length; i++) {
    c = str.charCodeAt(i)
    hi = c >> 8
    lo = c % 256
    byteArray.push(lo)
    byteArray.push(hi)
  }

  return byteArray
}

function base64ToBytes (str) {
  return base64.toByteArray(str)
}

function blitBuffer (src, dst, offset, length) {
  for (var i = 0; i < length; i++) {
    if ((i + offset >= dst.length) || (i >= src.length))
      break
    dst[i + offset] = src[i]
  }
  return i
}

function decodeUtf8Char (str) {
  try {
    return decodeURIComponent(str)
  } catch (err) {
    return String.fromCharCode(0xFFFD) // UTF 8 invalid char
  }
}

/*
 * We have to make sure that the value is a valid integer. This means that it
 * is non-negative. It has no fractional component and that it does not
 * exceed the maximum allowed value.
 */
function verifuint (value, max) {
  assert(typeof value === 'number', 'cannot write a non-number as a number')
  assert(value >= 0, 'specified a negative value for writing an unsigned value')
  assert(value <= max, 'value is larger than maximum value for type')
  assert(Math.floor(value) === value, 'value has a fractional component')
}

function verifsint (value, max, min) {
  assert(typeof value === 'number', 'cannot write a non-number as a number')
  assert(value <= max, 'value larger than maximum allowed value')
  assert(value >= min, 'value smaller than minimum allowed value')
  assert(Math.floor(value) === value, 'value has a fractional component')
}

function verifIEEE754 (value, max, min) {
  assert(typeof value === 'number', 'cannot write a non-number as a number')
  assert(value <= max, 'value larger than maximum allowed value')
  assert(value >= min, 'value smaller than minimum allowed value')
}

function assert (test, message) {
  if (!test) throw new Error(message || 'Failed assertion')
}

},{"base64-js":7,"ieee754":8}],7:[function(_dereq_,module,exports){
var lookup = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';

;(function (exports) {
	'use strict';

  var Arr = (typeof Uint8Array !== 'undefined')
    ? Uint8Array
    : Array

	var PLUS   = '+'.charCodeAt(0)
	var SLASH  = '/'.charCodeAt(0)
	var NUMBER = '0'.charCodeAt(0)
	var LOWER  = 'a'.charCodeAt(0)
	var UPPER  = 'A'.charCodeAt(0)

	function decode (elt) {
		var code = elt.charCodeAt(0)
		if (code === PLUS)
			return 62 // '+'
		if (code === SLASH)
			return 63 // '/'
		if (code < NUMBER)
			return -1 //no match
		if (code < NUMBER + 10)
			return code - NUMBER + 26 + 26
		if (code < UPPER + 26)
			return code - UPPER
		if (code < LOWER + 26)
			return code - LOWER + 26
	}

	function b64ToByteArray (b64) {
		var i, j, l, tmp, placeHolders, arr

		if (b64.length % 4 > 0) {
			throw new Error('Invalid string. Length must be a multiple of 4')
		}

		// the number of equal signs (place holders)
		// if there are two placeholders, than the two characters before it
		// represent one byte
		// if there is only one, then the three characters before it represent 2 bytes
		// this is just a cheap hack to not do indexOf twice
		var len = b64.length
		placeHolders = '=' === b64.charAt(len - 2) ? 2 : '=' === b64.charAt(len - 1) ? 1 : 0

		// base64 is 4/3 + up to two characters of the original data
		arr = new Arr(b64.length * 3 / 4 - placeHolders)

		// if there are placeholders, only get up to the last complete 4 chars
		l = placeHolders > 0 ? b64.length - 4 : b64.length

		var L = 0

		function push (v) {
			arr[L++] = v
		}

		for (i = 0, j = 0; i < l; i += 4, j += 3) {
			tmp = (decode(b64.charAt(i)) << 18) | (decode(b64.charAt(i + 1)) << 12) | (decode(b64.charAt(i + 2)) << 6) | decode(b64.charAt(i + 3))
			push((tmp & 0xFF0000) >> 16)
			push((tmp & 0xFF00) >> 8)
			push(tmp & 0xFF)
		}

		if (placeHolders === 2) {
			tmp = (decode(b64.charAt(i)) << 2) | (decode(b64.charAt(i + 1)) >> 4)
			push(tmp & 0xFF)
		} else if (placeHolders === 1) {
			tmp = (decode(b64.charAt(i)) << 10) | (decode(b64.charAt(i + 1)) << 4) | (decode(b64.charAt(i + 2)) >> 2)
			push((tmp >> 8) & 0xFF)
			push(tmp & 0xFF)
		}

		return arr
	}

	function uint8ToBase64 (uint8) {
		var i,
			extraBytes = uint8.length % 3, // if we have 1 byte left, pad 2 bytes
			output = "",
			temp, length

		function encode (num) {
			return lookup.charAt(num)
		}

		function tripletToBase64 (num) {
			return encode(num >> 18 & 0x3F) + encode(num >> 12 & 0x3F) + encode(num >> 6 & 0x3F) + encode(num & 0x3F)
		}

		// go through the array every three bytes, we'll deal with trailing stuff later
		for (i = 0, length = uint8.length - extraBytes; i < length; i += 3) {
			temp = (uint8[i] << 16) + (uint8[i + 1] << 8) + (uint8[i + 2])
			output += tripletToBase64(temp)
		}

		// pad the end with zeros, but make sure to not forget the extra bytes
		switch (extraBytes) {
			case 1:
				temp = uint8[uint8.length - 1]
				output += encode(temp >> 2)
				output += encode((temp << 4) & 0x3F)
				output += '=='
				break
			case 2:
				temp = (uint8[uint8.length - 2] << 8) + (uint8[uint8.length - 1])
				output += encode(temp >> 10)
				output += encode((temp >> 4) & 0x3F)
				output += encode((temp << 2) & 0x3F)
				output += '='
				break
		}

		return output
	}

	exports.toByteArray = b64ToByteArray
	exports.fromByteArray = uint8ToBase64
}(typeof exports === 'undefined' ? (this.base64js = {}) : exports))

},{}],8:[function(_dereq_,module,exports){
exports.read = function(buffer, offset, isLE, mLen, nBytes) {
  var e, m,
      eLen = nBytes * 8 - mLen - 1,
      eMax = (1 << eLen) - 1,
      eBias = eMax >> 1,
      nBits = -7,
      i = isLE ? (nBytes - 1) : 0,
      d = isLE ? -1 : 1,
      s = buffer[offset + i];

  i += d;

  e = s & ((1 << (-nBits)) - 1);
  s >>= (-nBits);
  nBits += eLen;
  for (; nBits > 0; e = e * 256 + buffer[offset + i], i += d, nBits -= 8);

  m = e & ((1 << (-nBits)) - 1);
  e >>= (-nBits);
  nBits += mLen;
  for (; nBits > 0; m = m * 256 + buffer[offset + i], i += d, nBits -= 8);

  if (e === 0) {
    e = 1 - eBias;
  } else if (e === eMax) {
    return m ? NaN : ((s ? -1 : 1) * Infinity);
  } else {
    m = m + Math.pow(2, mLen);
    e = e - eBias;
  }
  return (s ? -1 : 1) * m * Math.pow(2, e - mLen);
};

exports.write = function(buffer, value, offset, isLE, mLen, nBytes) {
  var e, m, c,
      eLen = nBytes * 8 - mLen - 1,
      eMax = (1 << eLen) - 1,
      eBias = eMax >> 1,
      rt = (mLen === 23 ? Math.pow(2, -24) - Math.pow(2, -77) : 0),
      i = isLE ? 0 : (nBytes - 1),
      d = isLE ? 1 : -1,
      s = value < 0 || (value === 0 && 1 / value < 0) ? 1 : 0;

  value = Math.abs(value);

  if (isNaN(value) || value === Infinity) {
    m = isNaN(value) ? 1 : 0;
    e = eMax;
  } else {
    e = Math.floor(Math.log(value) / Math.LN2);
    if (value * (c = Math.pow(2, -e)) < 1) {
      e--;
      c *= 2;
    }
    if (e + eBias >= 1) {
      value += rt / c;
    } else {
      value += rt * Math.pow(2, 1 - eBias);
    }
    if (value * c >= 2) {
      e++;
      c /= 2;
    }

    if (e + eBias >= eMax) {
      m = 0;
      e = eMax;
    } else if (e + eBias >= 1) {
      m = (value * c - 1) * Math.pow(2, mLen);
      e = e + eBias;
    } else {
      m = value * Math.pow(2, eBias - 1) * Math.pow(2, mLen);
      e = 0;
    }
  }

  for (; mLen >= 8; buffer[offset + i] = m & 0xff, i += d, m /= 256, mLen -= 8);

  e = (e << mLen) | m;
  eLen += mLen;
  for (; eLen > 0; buffer[offset + i] = e & 0xff, i += d, e /= 256, eLen -= 8);

  buffer[offset + i - d] |= s * 128;
};

},{}],9:[function(_dereq_,module,exports){
// shim for using process in browser

var process = module.exports = {};

process.nextTick = (function () {
    var canSetImmediate = typeof window !== 'undefined'
    && window.setImmediate;
    var canPost = typeof window !== 'undefined'
    && window.postMessage && window.addEventListener
    ;

    if (canSetImmediate) {
        return function (f) { return window.setImmediate(f) };
    }

    if (canPost) {
        var queue = [];
        window.addEventListener('message', function (ev) {
            var source = ev.source;
            if ((source === window || source === null) && ev.data === 'process-tick') {
                ev.stopPropagation();
                if (queue.length > 0) {
                    var fn = queue.shift();
                    fn();
                }
            }
        }, true);

        return function nextTick(fn) {
            queue.push(fn);
            window.postMessage('process-tick', '*');
        };
    }

    return function nextTick(fn) {
        setTimeout(fn, 0);
    };
})();

process.title = 'browser';
process.browser = true;
process.env = {};
process.argv = [];

function noop() {}

process.on = noop;
process.addListener = noop;
process.once = noop;
process.off = noop;
process.removeListener = noop;
process.removeAllListeners = noop;
process.emit = noop;

process.binding = function (name) {
    throw new Error('process.binding is not supported');
}

// TODO(shtylman)
process.cwd = function () { return '/' };
process.chdir = function (dir) {
    throw new Error('process.chdir is not supported');
};

},{}],10:[function(_dereq_,module,exports){
(function (Buffer){
function FilerBuffer (subject, encoding, nonZero) {

  // Automatically turn ArrayBuffer into Uint8Array so that underlying
  // Buffer code doesn't just throw away and ignore ArrayBuffer data.
  if (subject instanceof ArrayBuffer) {
    subject = new Uint8Array(subject);
  }

  return new Buffer(subject, encoding, nonZero);
};

// Inherit prototype from Buffer
FilerBuffer.prototype = Object.create(Buffer.prototype);
FilerBuffer.prototype.constructor = FilerBuffer;

// Also copy static methods onto FilerBuffer ctor
Object.keys(Buffer).forEach(function (p) {
  if (Buffer.hasOwnProperty(p)) {
    FilerBuffer[p] = Buffer[p];
  }
});

module.exports = FilerBuffer;

}).call(this,_dereq_("buffer").Buffer)
},{"buffer":6}],11:[function(_dereq_,module,exports){
var O_READ = 'READ';
var O_WRITE = 'WRITE';
var O_CREATE = 'CREATE';
var O_EXCLUSIVE = 'EXCLUSIVE';
var O_TRUNCATE = 'TRUNCATE';
var O_APPEND = 'APPEND';
var XATTR_CREATE = 'CREATE';
var XATTR_REPLACE = 'REPLACE';

module.exports = {
  FILE_SYSTEM_NAME: 'local',

  FILE_STORE_NAME: 'files',

  IDB_RO: 'readonly',
  IDB_RW: 'readwrite',

  WSQL_VERSION: "1",
  WSQL_SIZE: 5 * 1024 * 1024,
  WSQL_DESC: "FileSystem Storage",

  MODE_FILE: 'FILE',
  MODE_DIRECTORY: 'DIRECTORY',
  MODE_SYMBOLIC_LINK: 'SYMLINK',
  MODE_META: 'META',

  SYMLOOP_MAX: 10,

  BINARY_MIME_TYPE: 'application/octet-stream',
  JSON_MIME_TYPE: 'application/json',

  ROOT_DIRECTORY_NAME: '/', // basename(normalize(path))

  // FS Mount Flags
  FS_FORMAT: 'FORMAT',
  FS_NOCTIME: 'NOCTIME',
  FS_NOMTIME: 'NOMTIME',
  FS_NODUPEIDCHECK: 'FS_NODUPEIDCHECK',

  // FS File Open Flags
  O_READ: O_READ,
  O_WRITE: O_WRITE,
  O_CREATE: O_CREATE,
  O_EXCLUSIVE: O_EXCLUSIVE,
  O_TRUNCATE: O_TRUNCATE,
  O_APPEND: O_APPEND,

  O_FLAGS: {
    'r': [O_READ],
    'r+': [O_READ, O_WRITE],
    'w': [O_WRITE, O_CREATE, O_TRUNCATE],
    'w+': [O_WRITE, O_READ, O_CREATE, O_TRUNCATE],
    'wx': [O_WRITE, O_CREATE, O_EXCLUSIVE, O_TRUNCATE],
    'wx+': [O_WRITE, O_READ, O_CREATE, O_EXCLUSIVE, O_TRUNCATE],
    'a': [O_WRITE, O_CREATE, O_APPEND],
    'a+': [O_WRITE, O_READ, O_CREATE, O_APPEND],
    'ax': [O_WRITE, O_CREATE, O_EXCLUSIVE, O_APPEND],
    'ax+': [O_WRITE, O_READ, O_CREATE, O_EXCLUSIVE, O_APPEND]
  },

  XATTR_CREATE: XATTR_CREATE,
  XATTR_REPLACE: XATTR_REPLACE,

  FS_READY: 'READY',
  FS_PENDING: 'PENDING',
  FS_ERROR: 'ERROR',

  SUPER_NODE_ID: '00000000-0000-0000-0000-000000000000',

  // Reserved File Descriptors for streams
  STDIN: 0,
  STDOUT: 1,
  STDERR: 2,
  FIRST_DESCRIPTOR: 3,

  ENVIRONMENT: {
    TMP: '/tmp',
    PATH: ''
  }
};

},{}],12:[function(_dereq_,module,exports){
var MODE_FILE = _dereq_('./constants.js').MODE_FILE;

module.exports = function DirectoryEntry(id, type) {
  this.id = id;
  this.type = type || MODE_FILE;
};

},{"./constants.js":11}],13:[function(_dereq_,module,exports){
(function (Buffer){
// Adapt encodings to work with Buffer or Uint8Array, they expect the latter
function decode(buf) {
  return buf.toString('utf8');
}

function encode(string) {
  return new Buffer(string, 'utf8');
}

module.exports = {
  encode: encode,
  decode: decode
};

}).call(this,_dereq_("buffer").Buffer)
},{"buffer":6}],14:[function(_dereq_,module,exports){
var errors = {};
[
  /**
   * node.js errors - we only use some of these, add as needed.
   */
  //'-1:UNKNOWN:unknown error',
  //'0:OK:success',
  //'1:EOF:end of file',
  //'2:EADDRINFO:getaddrinfo error',
  //'3:EACCES:permission denied',
  //'4:EAGAIN:resource temporarily unavailable',
  //'5:EADDRINUSE:address already in use',
  //'6:EADDRNOTAVAIL:address not available',
  //'7:EAFNOSUPPORT:address family not supported',
  //'8:EALREADY:connection already in progress',
  '9:EBADF:bad file descriptor',
  '10:EBUSY:resource busy or locked',
  //'11:ECONNABORTED:software caused connection abort',
  //'12:ECONNREFUSED:connection refused',
  //'13:ECONNRESET:connection reset by peer',
  //'14:EDESTADDRREQ:destination address required',
  //'15:EFAULT:bad address in system call argument',
  //'16:EHOSTUNREACH:host is unreachable',
  //'17:EINTR:interrupted system call',
  '18:EINVAL:invalid argument',
  //'19:EISCONN:socket is already connected',
  //'20:EMFILE:too many open files',
  //'21:EMSGSIZE:message too long',
  //'22:ENETDOWN:network is down',
  //'23:ENETUNREACH:network is unreachable',
  //'24:ENFILE:file table overflow',
  //'25:ENOBUFS:no buffer space available',
  //'26:ENOMEM:not enough memory',
  '27:ENOTDIR:not a directory',
  '28:EISDIR:illegal operation on a directory',
  //'29:ENONET:machine is not on the network',
  // errno 30 skipped, as per https://github.com/rvagg/node-errno/blob/master/errno.js
  //'31:ENOTCONN:socket is not connected',
  //'32:ENOTSOCK:socket operation on non-socket',
  //'33:ENOTSUP:operation not supported on socket',
  '34:ENOENT:no such file or directory',
  //'35:ENOSYS:function not implemented',
  //'36:EPIPE:broken pipe',
  //'37:EPROTO:protocol error',
  //'38:EPROTONOSUPPORT:protocol not supported',
  //'39:EPROTOTYPE:protocol wrong type for socket',
  //'40:ETIMEDOUT:connection timed out',
  //'41:ECHARSET:invalid Unicode character',
  //'42:EAIFAMNOSUPPORT:address family for hostname not supported',
  // errno 43 skipped, as per https://github.com/rvagg/node-errno/blob/master/errno.js
  //'44:EAISERVICE:servname not supported for ai_socktype',
  //'45:EAISOCKTYPE:ai_socktype not supported',
  //'46:ESHUTDOWN:cannot send after transport endpoint shutdown',
  '47:EEXIST:file already exists',
  //'48:ESRCH:no such process',
  //'49:ENAMETOOLONG:name too long',
  //'50:EPERM:operation not permitted',
  '51:ELOOP:too many symbolic links encountered',
  //'52:EXDEV:cross-device link not permitted',
  '53:ENOTEMPTY:directory not empty',
  //'54:ENOSPC:no space left on device',
  '55:EIO:i/o error',
  //'56:EROFS:read-only file system',
  //'57:ENODEV:no such device',
  //'58:ESPIPE:invalid seek',
  //'59:ECANCELED:operation canceled',

  /**
   * Filer specific errors
   */
  '1000:ENOTMOUNTED:not mounted',
  '1001:EFILESYSTEMERROR:missing super node, use \'FORMAT\' flag to format filesystem.',
  '1002:ENOATTR:attribute does not exist'

].forEach(function(e) {
  e = e.split(':');
  var errno = +e[0];
  var errName = e[1];
  var defaultMessage = e[2];

  function FilerError(msg, path) {
    Error.call(this);

    this.name = errName;
    this.code = errName;
    this.errno = errno;
    this.message = msg || defaultMessage;
    if(path) {
      this.path = path;
    }
    this.stack = (new Error(this.message)).stack;
  }
  FilerError.prototype = Object.create(Error.prototype);
  FilerError.prototype.constructor = FilerError;
  FilerError.prototype.toString = function() {
    var pathInfo = this.path ? (', \'' + this.path + '\'') : '';
    return this.name + ': ' + this.message + pathInfo;
  };

  // We expose the error as both Errors.EINVAL and Errors[18]
  errors[errName] = errors[errno] = FilerError;
});

module.exports = errors;

},{}],15:[function(_dereq_,module,exports){
var _ = _dereq_('../../lib/nodash.js');

var Path = _dereq_('../path.js');
var normalize = Path.normalize;
var dirname = Path.dirname;
var basename = Path.basename;
var isAbsolutePath = Path.isAbsolute;
var isNullPath = Path.isNull;

var Constants = _dereq_('../constants.js');
var MODE_FILE = Constants.MODE_FILE;
var MODE_DIRECTORY = Constants.MODE_DIRECTORY;
var MODE_SYMBOLIC_LINK = Constants.MODE_SYMBOLIC_LINK;
var MODE_META = Constants.MODE_META;

var ROOT_DIRECTORY_NAME = Constants.ROOT_DIRECTORY_NAME;
var SUPER_NODE_ID = Constants.SUPER_NODE_ID;
var SYMLOOP_MAX = Constants.SYMLOOP_MAX;

var O_READ = Constants.O_READ;
var O_WRITE = Constants.O_WRITE;
var O_CREATE = Constants.O_CREATE;
var O_EXCLUSIVE = Constants.O_EXCLUSIVE;
var O_TRUNCATE = Constants.O_TRUNCATE;
var O_APPEND = Constants.O_APPEND;
var O_FLAGS = Constants.O_FLAGS;

var XATTR_CREATE = Constants.XATTR_CREATE;
var XATTR_REPLACE = Constants.XATTR_REPLACE;
var FS_NOMTIME = Constants.FS_NOMTIME;
var FS_NOCTIME = Constants.FS_NOCTIME;

var Encoding = _dereq_('../encoding.js');
var Errors = _dereq_('../errors.js');
var DirectoryEntry = _dereq_('../directory-entry.js');
var OpenFileDescription = _dereq_('../open-file-description.js');
var SuperNode = _dereq_('../super-node.js');
var Node = _dereq_('../node.js');
var Stats = _dereq_('../stats.js');
var Buffer = _dereq_('../buffer.js');

/**
 * Many functions below use this callback pattern. If it's not
 * re-defined, we use this to generate a callback. NOTE: this
 * can be use for callbacks of both forms without problem (i.e.,
 * since result will be undefined if not returned):
 *  - callback(error)
 *  - callback(error, result)
 */
function standard_check_result_cb(callback) {
  return function(error, result) {
    if(error) {
      callback(error);
    } else {
      callback(null, result);
    }
  };
}

/**
 * Update node times. Only passed times are modified (undefined times are ignored)
 * and filesystem flags are examined in order to override update logic.
 */
function update_node_times(context, path, node, times, callback) {
  // Honour mount flags for how we update times
  var flags = context.flags;
  if(_(flags).contains(FS_NOCTIME)) {
    delete times.ctime;
  }
  if(_(flags).contains(FS_NOMTIME)) {
    delete times.mtime;
  }

  // Only do the update if required (i.e., times are still present)
  var update = false;
  if(times.ctime) {
    node.ctime = times.ctime;
    // We don't do atime tracking for perf reasons, but do mirror ctime
    node.atime = times.ctime;
    update = true;
  }
  if(times.atime) {
    // The only time we explicitly pass atime is when utimes(), futimes() is called.
    // Override ctime mirror here if so
    node.atime = times.atime;
    update = true;
  }
  if(times.mtime) {
    node.mtime = times.mtime;
    update = true;
  }

  function complete(error) {
    // Queue this change so we can send watch events.
    // Unlike node.js, we send the full path vs. basename/dirname only.
    context.changes.push({ event: 'change', path: path });
    callback(error);
  }

  if(update) {
    context.putObject(node.id, node, complete);
  } else {
    complete();
  }
}

/**
 * make_node()
 */
// in: file or directory path
// out: new node representing file/directory
function make_node(context, path, mode, callback) {
  if(mode !== MODE_DIRECTORY && mode !== MODE_FILE) {
    return callback(new Errors.EINVAL('mode must be a directory or file', path));
  }

  path = normalize(path);

  var name = basename(path);
  var parentPath = dirname(path);
  var parentNode;
  var parentNodeData;
  var node;

  // Check if the parent node exists
  function create_node_in_parent(error, parentDirectoryNode) {
    if(error) {
      callback(error);
    } else if(parentDirectoryNode.mode !== MODE_DIRECTORY) {
      callback(new Errors.ENOTDIR('a component of the path prefix is not a directory', path));
    } else {
      parentNode = parentDirectoryNode;
      find_node(context, path, check_if_node_exists);
    }
  }

  // Check if the node to be created already exists
  function check_if_node_exists(error, result) {
    if(!error && result) {
      callback(new Errors.EEXIST('path name already exists', path));
    } else if(error && !(error instanceof Errors.ENOENT)) {
      callback(error);
    } else {
      context.getObject(parentNode.data, create_node);
    }
  }

  // Create the new node
  function create_node(error, result) {
    if(error) {
      callback(error);
    } else {
      parentNodeData = result;
      Node.create({guid: context.guid, mode: mode}, function(error, result) {
        if(error) {
          callback(error);
          return;
        }
        node = result;
        node.nlinks += 1;
        context.putObject(node.id, node, update_parent_node_data);
      });
    }
  }

  // Update parent node time
  function update_time(error) {
    if(error) {
      callback(error);
    } else {
      var now = Date.now();
      update_node_times(context, parentPath, node, { mtime: now, ctime: now }, callback);
    }
  }

  // Update the parent nodes data
  function update_parent_node_data(error) {
    if(error) {
      callback(error);
    } else {
      parentNodeData[name] = new DirectoryEntry(node.id, mode);
      context.putObject(parentNode.data, parentNodeData, update_time);
    }
  }

  // Find the parent node
  find_node(context, parentPath, create_node_in_parent);
}

/**
 * find_node
 */
// in: file or directory path
// out: node structure, or error
function find_node(context, path, callback) {
  path = normalize(path);
  if(!path) {
    return callback(new Errors.ENOENT('path is an empty string'));
  }
  var name = basename(path);
  var parentPath = dirname(path);
  var followedCount = 0;

  function read_root_directory_node(error, superNode) {
    if(error) {
      callback(error);
    } else if(!superNode || superNode.mode !== MODE_META || !superNode.rnode) {
      callback(new Errors.EFILESYSTEMERROR());
    } else {
      context.getObject(superNode.rnode, check_root_directory_node);
    }
  }

  function check_root_directory_node(error, rootDirectoryNode) {
    if(error) {
      callback(error);
    } else if(!rootDirectoryNode) {
      callback(new Errors.ENOENT());
    } else {
      callback(null, rootDirectoryNode);
    }
  }

  // in: parent directory node
  // out: parent directory data
  function read_parent_directory_data(error, parentDirectoryNode) {
    if(error) {
      callback(error);
    } else if(parentDirectoryNode.mode !== MODE_DIRECTORY || !parentDirectoryNode.data) {
      callback(new Errors.ENOTDIR('a component of the path prefix is not a directory', path));
    } else {
      context.getObject(parentDirectoryNode.data, get_node_from_parent_directory_data);
    }
  }

  // in: parent directory data
  // out: searched node
  function get_node_from_parent_directory_data(error, parentDirectoryData) {
    if(error) {
      callback(error);
    } else {
      if(!_(parentDirectoryData).has(name)) {
        callback(new Errors.ENOENT(null, path));
      } else {
        var nodeId = parentDirectoryData[name].id;
        context.getObject(nodeId, is_symbolic_link);
      }
    }
  }

  function is_symbolic_link(error, node) {
    if(error) {
      callback(error);
    } else {
      if(node.mode == MODE_SYMBOLIC_LINK) {
        followedCount++;
        if(followedCount > SYMLOOP_MAX){
          callback(new Errors.ELOOP(null, path));
        } else {
          follow_symbolic_link(node.data);
        }
      } else {
        callback(null, node);
      }
    }
  }

  function follow_symbolic_link(data) {
    data = normalize(data);
    parentPath = dirname(data);
    name = basename(data);
    if(ROOT_DIRECTORY_NAME == name) {
      context.getObject(SUPER_NODE_ID, read_root_directory_node);
    } else {
      find_node(context, parentPath, read_parent_directory_data);
    }
  }

  if(ROOT_DIRECTORY_NAME == name) {
    context.getObject(SUPER_NODE_ID, read_root_directory_node);
  } else {
    find_node(context, parentPath, read_parent_directory_data);
  }
}


/**
 * set extended attribute (refactor)
 */
function set_extended_attribute (context, path_or_fd, name, value, flag, callback) {
  var path;

  function set_xattr (error, node) {
    var xattr = (node ? node.xattrs[name] : null);

    function update_time(error) {
      if(error) {
        callback(error);
      } else {
        update_node_times(context, path, node, { ctime: Date.now() }, callback);
      }
    }

    if (error) {
      callback(error);
    }
    else if (flag === XATTR_CREATE && node.xattrs.hasOwnProperty(name)) {
      callback(new Errors.EEXIST('attribute already exists', path_or_fd));
    }
    else if (flag === XATTR_REPLACE && !node.xattrs.hasOwnProperty(name)) {
      callback(new Errors.ENOATTR(null, path_or_fd));
    }
    else {
      node.xattrs[name] = value;
      context.putObject(node.id, node, update_time);
    }
  }

  if (typeof path_or_fd == 'string') {
    path = path_or_fd;
    find_node(context, path_or_fd, set_xattr);
  }
  else if (typeof path_or_fd == 'object' && typeof path_or_fd.id == 'string') {
    path = path_or_fd.path;
    context.getObject(path_or_fd.id, set_xattr);
  }
  else {
    callback(new Errors.EINVAL('path or file descriptor of wrong type', path_or_fd));
  }
}

/**
 * ensure_root_directory. Creates a root node if necessary.
 *
 * Note: this should only be invoked when formatting a new file system.
 * Multiple invocations of this by separate instances will still result
 * in only a single super node.
 */
function ensure_root_directory(context, callback) {
  var superNode;
  var directoryNode;
  var directoryData;

  function ensure_super_node(error, existingNode) {
    if(!error && existingNode) {
      // Another instance has beat us and already created the super node.
      callback();
    } else if(error && !(error instanceof Errors.ENOENT)) {
      callback(error);
    } else {
      SuperNode.create({guid: context.guid}, function(error, result) {
        if(error) {
          callback(error);
          return;
        }
        superNode = result;
        context.putObject(superNode.id, superNode, write_directory_node);
      });
    }
  }

  function write_directory_node(error) {
    if(error) {
      callback(error);
    } else {
      Node.create({guid: context.guid, id: superNode.rnode, mode: MODE_DIRECTORY}, function(error, result) {
        if(error) {
          callback(error);
          return;
        }
        directoryNode = result;
        directoryNode.nlinks += 1;
        context.putObject(directoryNode.id, directoryNode, write_directory_data);
      });
    }
  }

  function write_directory_data(error) {
    if(error) {
      callback(error);
    } else {
      directoryData = {};
      context.putObject(directoryNode.data, directoryData, callback);
    }
  }

  context.getObject(SUPER_NODE_ID, ensure_super_node);
}

/**
 * make_directory
 */
function make_directory(context, path, callback) {
  path = normalize(path);
  var name = basename(path);
  var parentPath = dirname(path);

  var directoryNode;
  var directoryData;
  var parentDirectoryNode;
  var parentDirectoryData;

  function check_if_directory_exists(error, result) {
    if(!error && result) {
      callback(new Errors.EEXIST(null, path));
    } else if(error && !(error instanceof Errors.ENOENT)) {
      callback(error);
    } else {
      find_node(context, parentPath, read_parent_directory_data);
    }
  }

  function read_parent_directory_data(error, result) {
    if(error) {
      callback(error);
    } else {
      parentDirectoryNode = result;
      context.getObject(parentDirectoryNode.data, write_directory_node);
    }
  }

  function write_directory_node(error, result) {
    if(error) {
      callback(error);
    } else {
      parentDirectoryData = result;
      Node.create({guid: context.guid, mode: MODE_DIRECTORY}, function(error, result) {
        if(error) {
          callback(error);
          return;
        }
        directoryNode = result;
        directoryNode.nlinks += 1;
        context.putObject(directoryNode.id, directoryNode, write_directory_data);
      });
    }
  }

  function write_directory_data(error) {
    if(error) {
      callback(error);
    } else {
      directoryData = {};
      context.putObject(directoryNode.data, directoryData, update_parent_directory_data);
    }
  }

  function update_time(error) {
    if(error) {
      callback(error);
    } else {
      var now = Date.now();
      update_node_times(context, parentPath, parentDirectoryNode, { mtime: now, ctime: now }, callback);
    }
  }

  function update_parent_directory_data(error) {
    if(error) {
      callback(error);
    } else {
      parentDirectoryData[name] = new DirectoryEntry(directoryNode.id, MODE_DIRECTORY);
      context.putObject(parentDirectoryNode.data, parentDirectoryData, update_time);
    }
  }

  find_node(context, path, check_if_directory_exists);
}

/**
 * remove_directory
 */
function remove_directory(context, path, callback) {
  path = normalize(path);
  var name = basename(path);
  var parentPath = dirname(path);

  var directoryNode;
  var directoryData;
  var parentDirectoryNode;
  var parentDirectoryData;

  function read_parent_directory_data(error, result) {
    if(error) {
      callback(error);
    } else {
      parentDirectoryNode = result;
      context.getObject(parentDirectoryNode.data, check_if_node_exists);
    }
  }

  function check_if_node_exists(error, result) {
    if(error) {
      callback(error);
    } else if(ROOT_DIRECTORY_NAME == name) {
      callback(new Errors.EBUSY(null, path));
    } else if(!_(result).has(name)) {
      callback(new Errors.ENOENT(null, path));
    } else {
      parentDirectoryData = result;
      directoryNode = parentDirectoryData[name].id;
      context.getObject(directoryNode, check_if_node_is_directory);
    }
  }

  function check_if_node_is_directory(error, result) {
    if(error) {
      callback(error);
    } else if(result.mode != MODE_DIRECTORY) {
      callback(new Errors.ENOTDIR(null, path));
    } else {
      directoryNode = result;
      context.getObject(directoryNode.data, check_if_directory_is_empty);
    }
  }

  function check_if_directory_is_empty(error, result) {
    if(error) {
      callback(error);
    } else {
      directoryData = result;
      if(_(directoryData).size() > 0) {
        callback(new Errors.ENOTEMPTY(null, path));
      } else {
        remove_directory_entry_from_parent_directory_node();
      }
    }
  }

  function update_time(error) {
    if(error) {
      callback(error);
    } else {
      var now = Date.now();
      update_node_times(context, parentPath, parentDirectoryNode, { mtime: now, ctime: now }, remove_directory_node);
    }
  }

  function remove_directory_entry_from_parent_directory_node() {
    delete parentDirectoryData[name];
    context.putObject(parentDirectoryNode.data, parentDirectoryData, update_time);
  }

  function remove_directory_node(error) {
    if(error) {
      callback(error);
    } else {
      context.delete(directoryNode.id, remove_directory_data);
    }
  }

  function remove_directory_data(error) {
    if(error) {
      callback(error);
    } else {
      context.delete(directoryNode.data, callback);
    }
  }

  find_node(context, parentPath, read_parent_directory_data);
}

function open_file(context, path, flags, callback) {
  path = normalize(path);
  var name = basename(path);
  var parentPath = dirname(path);

  var directoryNode;
  var directoryData;
  var directoryEntry;
  var fileNode;
  var fileData;

  var followedCount = 0;

  if(ROOT_DIRECTORY_NAME == name) {
    if(_(flags).contains(O_WRITE)) {
      callback(new Errors.EISDIR('the named file is a directory and O_WRITE is set', path));
    } else {
      find_node(context, path, set_file_node);
    }
  } else {
    find_node(context, parentPath, read_directory_data);
  }

  function read_directory_data(error, result) {
    if(error) {
      callback(error);
    } else if(result.mode !== MODE_DIRECTORY) {
      callback(new Errors.ENOENT(null, path));
    } else {
      directoryNode = result;
      context.getObject(directoryNode.data, check_if_file_exists);
    }
  }

  function check_if_file_exists(error, result) {
    if(error) {
      callback(error);
    } else {
      directoryData = result;
      if(_(directoryData).has(name)) {
        if(_(flags).contains(O_EXCLUSIVE)) {
          callback(new Errors.ENOENT('O_CREATE and O_EXCLUSIVE are set, and the named file exists', path));
        } else {
          directoryEntry = directoryData[name];
          if(directoryEntry.type == MODE_DIRECTORY && _(flags).contains(O_WRITE)) {
            callback(new Errors.EISDIR('the named file is a directory and O_WRITE is set', path));
          } else {
            context.getObject(directoryEntry.id, check_if_symbolic_link);
          }
        }
      } else {
        if(!_(flags).contains(O_CREATE)) {
          callback(new Errors.ENOENT('O_CREATE is not set and the named file does not exist', path));
        } else {
          write_file_node();
        }
      }
    }
  }

  function check_if_symbolic_link(error, result) {
    if(error) {
      callback(error);
    } else {
      var node = result;
      if(node.mode == MODE_SYMBOLIC_LINK) {
        followedCount++;
        if(followedCount > SYMLOOP_MAX){
          callback(new Errors.ELOOP(null, path));
        } else {
          follow_symbolic_link(node.data);
        }
      } else {
        set_file_node(undefined, node);
      }
    }
  }

  function follow_symbolic_link(data) {
    data = normalize(data);
    parentPath = dirname(data);
    name = basename(data);
    if(ROOT_DIRECTORY_NAME == name) {
      if(_(flags).contains(O_WRITE)) {
        callback(new Errors.EISDIR('the named file is a directory and O_WRITE is set', path));
      } else {
        find_node(context, path, set_file_node);
      }
    }
    find_node(context, parentPath, read_directory_data);
  }

  function set_file_node(error, result) {
    if(error) {
      callback(error);
    } else {
      fileNode = result;
      callback(null, fileNode);
    }
  }

  function write_file_node() {
    Node.create({guid: context.guid, mode: MODE_FILE}, function(error, result) {
      if(error) {
        callback(error);
        return;
      }
      fileNode = result;
      fileNode.nlinks += 1;
      context.putObject(fileNode.id, fileNode, write_file_data);
    });
  }

  function write_file_data(error) {
    if(error) {
      callback(error);
    } else {
      fileData = new Buffer(0);
      fileData.fill(0);
      context.putBuffer(fileNode.data, fileData, update_directory_data);
    }
  }

  function update_time(error) {
    if(error) {
      callback(error);
    } else {
      var now = Date.now();
      update_node_times(context, parentPath, directoryNode, { mtime: now, ctime: now }, handle_update_result);
    }
  }

  function update_directory_data(error) {
    if(error) {
      callback(error);
    } else {
      directoryData[name] = new DirectoryEntry(fileNode.id, MODE_FILE);
      context.putObject(directoryNode.data, directoryData, update_time);
    }
  }

  function handle_update_result(error) {
    if(error) {
      callback(error);
    } else {
      callback(null, fileNode);
    }
  }
}

function replace_data(context, ofd, buffer, offset, length, callback) {
  var fileNode;

  function return_nbytes(error) {
    if(error) {
      callback(error);
    } else {
      callback(null, length);
    }
  }

  function update_time(error) {
    if(error) {
      callback(error);
    } else {
      var now = Date.now();
      update_node_times(context, ofd.path, fileNode, { mtime: now, ctime: now }, return_nbytes);
    }
  }

  function update_file_node(error) {
    if(error) {
      callback(error);
    } else {
      context.putObject(fileNode.id, fileNode, update_time);
    }
  }

  function write_file_data(error, result) {
    if(error) {
      callback(error);
    } else {
      fileNode = result;
      var newData = new Buffer(length);
      newData.fill(0);
      buffer.copy(newData, 0, offset, offset + length);
      ofd.position = length;

      fileNode.size = length;
      fileNode.version += 1;

      context.putBuffer(fileNode.data, newData, update_file_node);
    }
  }

  context.getObject(ofd.id, write_file_data);
}

function write_data(context, ofd, buffer, offset, length, position, callback) {
  var fileNode;
  var fileData;

  function return_nbytes(error) {
    if(error) {
      callback(error);
    } else {
      callback(null, length);
    }
  }

  function update_time(error) {
    if(error) {
      callback(error);
    } else {
      var now = Date.now();
      update_node_times(context, ofd.path, fileNode, { mtime: now, ctime: now }, return_nbytes);
    }
  }

  function update_file_node(error) {
    if(error) {
      callback(error);
    } else {
      context.putObject(fileNode.id, fileNode, update_time);
    }
  }

  function update_file_data(error, result) {
    if(error) {
      callback(error);
    } else {
      fileData = result;
      if(!fileData) {
        return callback(new Errors.EIO('Expected Buffer'));
      }
      var _position = (!(undefined === position || null === position)) ? position : ofd.position;
      var newSize = Math.max(fileData.length, _position + length);
      var newData = new Buffer(newSize);
      newData.fill(0);
      if(fileData) {
        fileData.copy(newData);
      }
      buffer.copy(newData, _position, offset, offset + length);
      if(undefined === position) {
        ofd.position += length;
      }

      fileNode.size = newSize;
      fileNode.version += 1;

      context.putBuffer(fileNode.data, newData, update_file_node);
    }
  }

  function read_file_data(error, result) {
    if(error) {
      callback(error);
    } else {
      fileNode = result;
      context.getBuffer(fileNode.data, update_file_data);
    }
  }

  context.getObject(ofd.id, read_file_data);
}

function read_data(context, ofd, buffer, offset, length, position, callback) {
  var fileNode;
  var fileData;

  function handle_file_data(error, result) {
    if(error) {
      callback(error);
    } else {
      fileData = result;
      if(!fileData) {
        return callback(new Errors.EIO('Expected Buffer'));
      }
      var _position = (!(undefined === position || null === position)) ? position : ofd.position;
      length = (_position + length > buffer.length) ? length - _position : length;
      fileData.copy(buffer, offset, _position, _position + length);
      if(undefined === position) {
        ofd.position += length;
      }
      callback(null, length);
    }
  }

  function read_file_data(error, result) {
    if(error) {
      callback(error);
    } else {
      fileNode = result;
      context.getBuffer(fileNode.data, handle_file_data);
    }
  }

  context.getObject(ofd.id, read_file_data);
}

function stat_file(context, path, callback) {
  path = normalize(path);
  var name = basename(path);
  find_node(context, path, standard_check_result_cb(callback));
}

function fstat_file(context, ofd, callback) {
  context.getObject(ofd.id, standard_check_result_cb(callback));
}

function lstat_file(context, path, callback) {
  path = normalize(path);
  var name = basename(path);
  var parentPath = dirname(path);

  var directoryNode;
  var directoryData;

  if(ROOT_DIRECTORY_NAME == name) {
    find_node(context, path, standard_check_result_cb(callback));
  } else {
    find_node(context, parentPath, read_directory_data);
  }

  function read_directory_data(error, result) {
    if(error) {
      callback(error);
    } else {
      directoryNode = result;
      context.getObject(directoryNode.data, check_if_file_exists);
    }
  }

  function check_if_file_exists(error, result) {
    if(error) {
      callback(error);
    } else {
      directoryData = result;
      if(!_(directoryData).has(name)) {
        callback(new Errors.ENOENT('a component of the path does not name an existing file', path));
      } else {
        context.getObject(directoryData[name].id, standard_check_result_cb(callback));
      }
    }
  }
}

function link_node(context, oldpath, newpath, callback) {
  oldpath = normalize(oldpath);
  var oldname = basename(oldpath);
  var oldParentPath = dirname(oldpath);

  newpath = normalize(newpath);
  var newname = basename(newpath);
  var newParentPath = dirname(newpath);

  var oldDirectoryNode;
  var oldDirectoryData;
  var newDirectoryNode;
  var newDirectoryData;
  var fileNode;

  function update_time(error) {
    if(error) {
      callback(error);
    } else {
      update_node_times(context, newpath,  fileNode, { ctime: Date.now() }, callback);
    }
  }

  function update_file_node(error, result) {
    if(error) {
      callback(error);
    } else {
      fileNode = result;
      fileNode.nlinks += 1;
      context.putObject(fileNode.id, fileNode, update_time);
    }
  }

  function read_directory_entry(error, result) {
    if(error) {
      callback(error);
    } else {
      context.getObject(newDirectoryData[newname].id, update_file_node);
    }
  }

  function check_if_new_file_exists(error, result) {
    if(error) {
      callback(error);
    } else {
      newDirectoryData = result;
      if(_(newDirectoryData).has(newname)) {
        callback(new Errors.EEXIST('newpath resolves to an existing file', newname));
      } else {
        newDirectoryData[newname] = oldDirectoryData[oldname];
        context.putObject(newDirectoryNode.data, newDirectoryData, read_directory_entry);
      }
    }
  }

  function read_new_directory_data(error, result) {
    if(error) {
      callback(error);
    } else {
      newDirectoryNode = result;
      context.getObject(newDirectoryNode.data, check_if_new_file_exists);
    }
  }

  function check_if_old_file_exists(error, result) {
    if(error) {
      callback(error);
    } else {
      oldDirectoryData = result;
      if(!_(oldDirectoryData).has(oldname)) {
        callback(new Errors.ENOENT('a component of either path prefix does not exist', oldname));
      } else {
        find_node(context, newParentPath, read_new_directory_data);
      }
    }
  }

  function read_old_directory_data(error, result) {
    if(error) {
      callback(error);
    } else {
      oldDirectoryNode = result;
      context.getObject(oldDirectoryNode.data, check_if_old_file_exists);
    }
  }

  find_node(context, oldParentPath, read_old_directory_data);
}

function unlink_node(context, path, callback) {
  path = normalize(path);
  var name = basename(path);
  var parentPath = dirname(path);

  var directoryNode;
  var directoryData;
  var fileNode;

  function update_directory_data(error) {
    if(error) {
      callback(error);
    } else {
      delete directoryData[name];
      context.putObject(directoryNode.data, directoryData, function(error) {
        var now = Date.now();
        update_node_times(context, parentPath, directoryNode, { mtime: now, ctime: now }, callback);
      });
    }
  }

  function delete_file_data(error) {
    if(error) {
      callback(error);
    } else {
      context.delete(fileNode.data, update_directory_data);
    }
  }

  function update_file_node(error, result) {
    if(error) {
      callback(error);
    } else {
      fileNode = result;
      fileNode.nlinks -= 1;
      if(fileNode.nlinks < 1) {
        context.delete(fileNode.id, delete_file_data);
      } else {
        context.putObject(fileNode.id, fileNode, function(error) {
          update_node_times(context, path, fileNode, { ctime: Date.now() }, update_directory_data);
        });
      }
    }
  }

  function check_if_file_exists(error, result) {
    if(error) {
      callback(error);
    } else {
      directoryData = result;
      if(!_(directoryData).has(name)) {
        callback(new Errors.ENOENT('a component of the path does not name an existing file', name));
      } else {
        context.getObject(directoryData[name].id, update_file_node);
      }
    }
  }

  function read_directory_data(error, result) {
    if(error) {
      callback(error);
    } else {
      directoryNode = result;
      context.getObject(directoryNode.data, check_if_file_exists);
    }
  }

  find_node(context, parentPath, read_directory_data);
}

function read_directory(context, path, callback) {
  path = normalize(path);
  var name = basename(path);

  var directoryNode;
  var directoryData;

  function handle_directory_data(error, result) {
    if(error) {
      callback(error);
    } else {
      directoryData = result;
      var files = Object.keys(directoryData);
      callback(null, files);
    }
  }

  function read_directory_data(error, result) {
    if(error) {
      callback(error);
    } else if(result.mode !== MODE_DIRECTORY) {
      callback(new Errors.ENOTDIR(null, path));
    } else {
      directoryNode = result;
      context.getObject(directoryNode.data, handle_directory_data);
    }
  }

  find_node(context, path, read_directory_data);
}

function make_symbolic_link(context, srcpath, dstpath, callback) {
  dstpath = normalize(dstpath);
  var name = basename(dstpath);
  var parentPath = dirname(dstpath);

  var directoryNode;
  var directoryData;
  var fileNode;

  if(ROOT_DIRECTORY_NAME == name) {
    callback(new Errors.EEXIST(null, name));
  } else {
    find_node(context, parentPath, read_directory_data);
  }

  function read_directory_data(error, result) {
    if(error) {
      callback(error);
    } else {
      directoryNode = result;
      context.getObject(directoryNode.data, check_if_file_exists);
    }
  }

  function check_if_file_exists(error, result) {
    if(error) {
      callback(error);
    } else {
      directoryData = result;
      if(_(directoryData).has(name)) {
        callback(new Errors.EEXIST(null, name));
      } else {
        write_file_node();
      }
    }
  }

  function write_file_node() {
    Node.create({guid: context.guid, mode: MODE_SYMBOLIC_LINK}, function(error, result) {
      if(error) {
        callback(error);
        return;
      }
      fileNode = result;
      fileNode.nlinks += 1;
      fileNode.size = srcpath.length;
      fileNode.data = srcpath;
      context.putObject(fileNode.id, fileNode, update_directory_data);
    });
  }

  function update_time(error) {
    if(error) {
      callback(error);
    } else {
      var now = Date.now();
      update_node_times(context, parentPath, directoryNode, { mtime: now, ctime: now }, callback);
    }
  }

  function update_directory_data(error) {
    if(error) {
      callback(error);
    } else {
      directoryData[name] = new DirectoryEntry(fileNode.id, MODE_SYMBOLIC_LINK);
      context.putObject(directoryNode.data, directoryData, update_time);
    }
  }
}

function read_link(context, path, callback) {
  path = normalize(path);
  var name = basename(path);
  var parentPath = dirname(path);

  var directoryNode;
  var directoryData;

  find_node(context, parentPath, read_directory_data);

  function read_directory_data(error, result) {
    if(error) {
      callback(error);
    } else {
      directoryNode = result;
      context.getObject(directoryNode.data, check_if_file_exists);
    }
  }

  function check_if_file_exists(error, result) {
    if(error) {
      callback(error);
    } else {
      directoryData = result;
      if(!_(directoryData).has(name)) {
        callback(new Errors.ENOENT('a component of the path does not name an existing file', name));
      } else {
        context.getObject(directoryData[name].id, check_if_symbolic);
      }
    }
  }

  function check_if_symbolic(error, result) {
    if(error) {
      callback(error);
    } else {
      if(result.mode != MODE_SYMBOLIC_LINK) {
        callback(new Errors.EINVAL('path not a symbolic link', path));
      } else {
        callback(null, result.data);
      }
    }
  }
}

function truncate_file(context, path, length, callback) {
  path = normalize(path);

  var fileNode;

  function read_file_data (error, node) {
    if (error) {
      callback(error);
    } else if(node.mode == MODE_DIRECTORY ) {
      callback(new Errors.EISDIR(null, path));
    } else{
      fileNode = node;
      context.getBuffer(fileNode.data, truncate_file_data);
    }
  }

  function truncate_file_data(error, fileData) {
    if (error) {
      callback(error);
    } else {
      if(!fileData) {
        return callback(new Errors.EIO('Expected Buffer'));
      }
      var data = new Buffer(length);
      data.fill(0);
      if(fileData) {
        fileData.copy(data);
      }
      context.putBuffer(fileNode.data, data, update_file_node);
    }
  }

  function update_time(error) {
    if(error) {
      callback(error);
    } else {
      var now = Date.now();
      update_node_times(context, path, fileNode, { mtime: now, ctime: now }, callback);
    }
  }

  function update_file_node (error) {
    if(error) {
      callback(error);
    } else {
      fileNode.size = length;
      fileNode.version += 1;
      context.putObject(fileNode.id, fileNode, update_time);
    }
  }

  if(length < 0) {
    callback(new Errors.EINVAL('length cannot be negative'));
  } else {
    find_node(context, path, read_file_data);
  }
}

function ftruncate_file(context, ofd, length, callback) {
  var fileNode;

  function read_file_data (error, node) {
    if (error) {
      callback(error);
    } else if(node.mode == MODE_DIRECTORY ) {
      callback(new Errors.EISDIR());
    } else{
      fileNode = node;
      context.getBuffer(fileNode.data, truncate_file_data);
    }
  }

  function truncate_file_data(error, fileData) {
    if (error) {
      callback(error);
    } else {
      var data;
      if(!fileData) {
        return callback(new Errors.EIO('Expected Buffer'));
      }
      if(fileData) {
        data = fileData.slice(0, length);
      } else {
        data = new Buffer(length);
        data.fill(0);
      }
      context.putBuffer(fileNode.data, data, update_file_node);
    }
  }

  function update_time(error) {
    if(error) {
      callback(error);
    } else {
      var now = Date.now();
      update_node_times(context, ofd.path, fileNode, { mtime: now, ctime: now }, callback);
    }
  }

  function update_file_node (error) {
    if(error) {
      callback(error);
    } else {
      fileNode.size = length;
      fileNode.version += 1;
      context.putObject(fileNode.id, fileNode, update_time);
    }
  }

  if(length < 0) {
    callback(new Errors.EINVAL('length cannot be negative'));
  } else {
    context.getObject(ofd.id, read_file_data);
  }
}

function utimes_file(context, path, atime, mtime, callback) {
  path = normalize(path);

  function update_times(error, node) {
    if (error) {
      callback(error);
    } else {
      update_node_times(context, path, node, { atime: atime, ctime: mtime, mtime: mtime }, callback);
    }
  }

  if (typeof atime != 'number' || typeof mtime != 'number') {
    callback(new Errors.EINVAL('atime and mtime must be number', path));
  }
  else if (atime < 0 || mtime < 0) {
    callback(new Errors.EINVAL('atime and mtime must be positive integers', path));
  }
  else {
    find_node(context, path, update_times);
  }
}

function futimes_file(context, ofd, atime, mtime, callback) {

  function update_times (error, node) {
    if (error) {
      callback(error);
    } else {
      update_node_times(context, ofd.path, node, { atime: atime, ctime: mtime, mtime: mtime }, callback);
    }
  }

  if (typeof atime != 'number' || typeof mtime != 'number') {
    callback(new Errors.EINVAL('atime and mtime must be a number'));
  }
  else if (atime < 0 || mtime < 0) {
    callback(new Errors.EINVAL('atime and mtime must be positive integers'));
  }
  else {
    context.getObject(ofd.id, update_times);
  }
}

function setxattr_file(context, path, name, value, flag, callback) {
  path = normalize(path);

  if (typeof name != 'string') {
    callback(new Errors.EINVAL('attribute name must be a string', path));
  }
  else if (!name) {
    callback(new Errors.EINVAL('attribute name cannot be an empty string', path));
  }
  else if (flag !== null &&
           flag !== XATTR_CREATE && flag !== XATTR_REPLACE) {
    callback(new Errors.EINVAL('invalid flag, must be null, XATTR_CREATE or XATTR_REPLACE', path));
  }
  else {
    set_extended_attribute(context, path, name, value, flag, callback);
  }
}

function fsetxattr_file (context, ofd, name, value, flag, callback) {
  if (typeof name != 'string') {
    callback(new Errors.EINVAL('attribute name must be a string'));
  }
  else if (!name) {
    callback(new Errors.EINVAL('attribute name cannot be an empty string'));
  }
  else if (flag !== null &&
           flag !== XATTR_CREATE && flag !== XATTR_REPLACE) {
    callback(new Errors.EINVAL('invalid flag, must be null, XATTR_CREATE or XATTR_REPLACE'));
  }
  else {
    set_extended_attribute(context, ofd, name, value, flag, callback);
  }
}

function getxattr_file (context, path, name, callback) {
  path = normalize(path);

  function get_xattr(error, node) {
    var xattr = (node ? node.xattrs[name] : null);

    if (error) {
      callback (error);
    }
    else if (!node.xattrs.hasOwnProperty(name)) {
      callback(new Errors.ENOATTR(null, path));
    }
    else {
      callback(null, node.xattrs[name]);
    }
  }

  if (typeof name != 'string') {
    callback(new Errors.EINVAL('attribute name must be a string', path));
  }
  else if (!name) {
    callback(new Errors.EINVAL('attribute name cannot be an empty string', path));
  }
  else {
    find_node(context, path, get_xattr);
  }
}

function fgetxattr_file (context, ofd, name, callback) {

  function get_xattr (error, node) {
    var xattr = (node ? node.xattrs[name] : null);

    if (error) {
      callback(error);
    }
    else if (!node.xattrs.hasOwnProperty(name)) {
      callback(new Errors.ENOATTR());
    }
    else {
      callback(null, node.xattrs[name]);
    }
  }

  if (typeof name != 'string') {
    callback(new Errors.EINVAL());
  }
  else if (!name) {
    callback(new Errors.EINVAL('attribute name cannot be an empty string'));
  }
  else {
    context.getObject(ofd.id, get_xattr);
  }
}

function removexattr_file (context, path, name, callback) {
  path = normalize(path);

  function remove_xattr (error, node) {
    var xattr = (node ? node.xattrs : null);

    function update_time(error) {
      if(error) {
        callback(error);
      } else {
        update_node_times(context, path, node, { ctime: Date.now() }, callback);
      }
    }

    if (error) {
      callback(error);
    }
    else if (!xattr.hasOwnProperty(name)) {
      callback(new Errors.ENOATTR(null, path));
    }
    else {
      delete node.xattrs[name];
      context.putObject(node.id, node, update_time);
    }
  }

  if (typeof name != 'string') {
    callback(new Errors.EINVAL('attribute name must be a string', path));
  }
  else if (!name) {
    callback(new Errors.EINVAL('attribute name cannot be an empty string', path));
  }
  else {
    find_node(context, path, remove_xattr);
  }
}

function fremovexattr_file (context, ofd, name, callback) {

  function remove_xattr (error, node) {
    function update_time(error) {
      if(error) {
        callback(error);
      } else {
        update_node_times(context, ofd.path, node, { ctime: Date.now() }, callback);
      }
    }

    if (error) {
      callback(error);
    }
    else if (!node.xattrs.hasOwnProperty(name)) {
      callback(new Errors.ENOATTR());
    }
    else {
      delete node.xattrs[name];
      context.putObject(node.id, node, update_time);
    }
  }

  if (typeof name != 'string') {
    callback(new Errors.EINVAL('attribute name must be a string'));
  }
  else if (!name) {
    callback(new Errors.EINVAL('attribute name cannot be an empty string'));
  }
  else {
    context.getObject(ofd.id, remove_xattr);
  }
}

function validate_flags(flags) {
  if(!_(O_FLAGS).has(flags)) {
    return null;
  }
  return O_FLAGS[flags];
}

function validate_file_options(options, enc, fileMode){
  if(!options) {
    options = { encoding: enc, flag: fileMode };
  } else if(typeof options === "function") {
    options = { encoding: enc, flag: fileMode };
  } else if(typeof options === "string") {
    options = { encoding: options, flag: fileMode };
  }
  return options;
}

function pathCheck(path, callback) {
  var err;

  if(!path) {
    err = new Errors.EINVAL('Path must be a string', path);
  } else if(isNullPath(path)) {
    err = new Errors.EINVAL('Path must be a string without null bytes.', path);
  } else if(!isAbsolutePath(path)) {
    err = new Errors.EINVAL('Path must be absolute.', path);
  }

  if(err) {
    callback(err);
    return false;
  }
  return true;
}


function open(fs, context, path, flags, mode, callback) {
  // NOTE: we support the same signature as node with a `mode` arg,
  // but ignore it.
  callback = arguments[arguments.length - 1];
  if(!pathCheck(path, callback)) return;

  function check_result(error, fileNode) {
    if(error) {
      callback(error);
    } else {
      var position;
      if(_(flags).contains(O_APPEND)) {
        position = fileNode.size;
      } else {
        position = 0;
      }
      var openFileDescription = new OpenFileDescription(path, fileNode.id, flags, position);
      var fd = fs.allocDescriptor(openFileDescription);
      callback(null, fd);
    }
  }

  flags = validate_flags(flags);
  if(!flags) {
    callback(new Errors.EINVAL('flags is not valid'), path);
  }

  open_file(context, path, flags, check_result);
}

function close(fs, context, fd, callback) {
  if(!_(fs.openFiles).has(fd)) {
    callback(new Errors.EBADF());
  } else {
    fs.releaseDescriptor(fd);
    callback(null);
  }
}

function mknod(fs, context, path, mode, callback) {
  if(!pathCheck(path, callback)) return;
  make_node(context, path, mode, callback);
}

function mkdir(fs, context, path, mode, callback) {
  // NOTE: we support passing a mode arg, but we ignore it internally for now.
  callback = arguments[arguments.length - 1];
  if(!pathCheck(path, callback)) return;
  make_directory(context, path, standard_check_result_cb(callback));
}

function rmdir(fs, context, path, callback) {
  if(!pathCheck(path, callback)) return;
  remove_directory(context, path, standard_check_result_cb(callback));
}

function stat(fs, context, path, callback) {
  if(!pathCheck(path, callback)) return;

  function check_result(error, result) {
    if(error) {
      callback(error);
    } else {
      var stats = new Stats(result, fs.name);
      callback(null, stats);
    }
  }

  stat_file(context, path, check_result);
}

function fstat(fs, context, fd, callback) {
  function check_result(error, result) {
    if(error) {
      callback(error);
    } else {
      var stats = new Stats(result, fs.name);
      callback(null, stats);
    }
  }

  var ofd = fs.openFiles[fd];
  if(!ofd) {
    callback(new Errors.EBADF());
  } else {
    fstat_file(context, ofd, check_result);
  }
}

function link(fs, context, oldpath, newpath, callback) {
  if(!pathCheck(oldpath, callback)) return;
  if(!pathCheck(newpath, callback)) return;
  link_node(context, oldpath, newpath, standard_check_result_cb(callback));
}

function unlink(fs, context, path, callback) {
  if(!pathCheck(path, callback)) return;
  unlink_node(context, path, standard_check_result_cb(callback));
}

function read(fs, context, fd, buffer, offset, length, position, callback) {
  // Follow how node.js does this
  function wrapped_cb(err, bytesRead) {
    // Retain a reference to buffer so that it can't be GC'ed too soon.
    callback(err, bytesRead || 0, buffer);
  }

  offset = (undefined === offset) ? 0 : offset;
  length = (undefined === length) ? buffer.length - offset : length;
  callback = arguments[arguments.length - 1];

  var ofd = fs.openFiles[fd];
  if(!ofd) {
    callback(new Errors.EBADF());
  } else if(!_(ofd.flags).contains(O_READ)) {
    callback(new Errors.EBADF('descriptor does not permit reading'));
  } else {
    read_data(context, ofd, buffer, offset, length, position, standard_check_result_cb(wrapped_cb));
  }
}

function readFile(fs, context, path, options, callback) {
  callback = arguments[arguments.length - 1];
  options = validate_file_options(options, null, 'r');

  if(!pathCheck(path, callback)) return;

  var flags = validate_flags(options.flag || 'r');
  if(!flags) {
    return callback(new Errors.EINVAL('flags is not valid', path));
  }

  open_file(context, path, flags, function(err, fileNode) {
    if(err) {
      return callback(err);
    }
    var ofd = new OpenFileDescription(path, fileNode.id, flags, 0);
    var fd = fs.allocDescriptor(ofd);

    function cleanup() {
      fs.releaseDescriptor(fd);
    }

    fstat_file(context, ofd, function(err, fstatResult) {
      if(err) {
        cleanup();
        return callback(err);
      }

      var stats = new Stats(fstatResult, fs.name);

      if(stats.isDirectory()) {
        cleanup();
        return callback(new Errors.EISDIR('illegal operation on directory', path));
      }

      var size = stats.size;
      var buffer = new Buffer(size);
      buffer.fill(0);

      read_data(context, ofd, buffer, 0, size, 0, function(err, nbytes) {
        cleanup();

        if(err) {
          return callback(err);
        }

        var data;
        if(options.encoding === 'utf8') {
          data = Encoding.decode(buffer);
        } else {
          data = buffer;
        }
        callback(null, data);
      });
    });
  });
}

function write(fs, context, fd, buffer, offset, length, position, callback) {
  callback = arguments[arguments.length - 1];
  offset = (undefined === offset) ? 0 : offset;
  length = (undefined === length) ? buffer.length - offset : length;

  var ofd = fs.openFiles[fd];
  if(!ofd) {
    callback(new Errors.EBADF());
  } else if(!_(ofd.flags).contains(O_WRITE)) {
    callback(new Errors.EBADF('descriptor does not permit writing'));
  } else if(buffer.length - offset < length) {
    callback(new Errors.EIO('intput buffer is too small'));
  } else {
    write_data(context, ofd, buffer, offset, length, position, standard_check_result_cb(callback));
  }
}

function writeFile(fs, context, path, data, options, callback) {
  callback = arguments[arguments.length - 1];
  options = validate_file_options(options, 'utf8', 'w');

  if(!pathCheck(path, callback)) return;

  var flags = validate_flags(options.flag || 'w');
  if(!flags) {
    return callback(new Errors.EINVAL('flags is not valid', path));
  }

  data = data || '';
  if(typeof data === "number") {
    data = '' + data;
  }
  if(typeof data === "string" && options.encoding === 'utf8') {
    data = Encoding.encode(data);
  }

  open_file(context, path, flags, function(err, fileNode) {
    if(err) {
      return callback(err);
    }
    var ofd = new OpenFileDescription(path, fileNode.id, flags, 0);
    var fd = fs.allocDescriptor(ofd);

    replace_data(context, ofd, data, 0, data.length, function(err, nbytes) {
      fs.releaseDescriptor(fd);

      if(err) {
        return callback(err);
      }
      callback(null);
    });
  });
}

function appendFile(fs, context, path, data, options, callback) {
  callback = arguments[arguments.length - 1];
  options = validate_file_options(options, 'utf8', 'a');

  if(!pathCheck(path, callback)) return;

  var flags = validate_flags(options.flag || 'a');
  if(!flags) {
    return callback(new Errors.EINVAL('flags is not valid', path));
  }

  data = data || '';
  if(typeof data === "number") {
    data = '' + data;
  }
  if(typeof data === "string" && options.encoding === 'utf8') {
    data = Encoding.encode(data);
  }

  open_file(context, path, flags, function(err, fileNode) {
    if(err) {
      return callback(err);
    }
    var ofd = new OpenFileDescription(path, fileNode.id, flags, fileNode.size);
    var fd = fs.allocDescriptor(ofd);

    write_data(context, ofd, data, 0, data.length, ofd.position, function(err, nbytes) {
      fs.releaseDescriptor(fd);

      if(err) {
        return callback(err);
      }
      callback(null);
    });
  });
}

function exists(fs, context, path, callback) {
  function cb(err, stats) {
    callback(err ? false : true);
  }
  stat(fs, context, path, cb);
}

function getxattr(fs, context, path, name, callback) {
  if (!pathCheck(path, callback)) return;
  getxattr_file(context, path, name, standard_check_result_cb(callback));
}

function fgetxattr(fs, context, fd, name, callback) {
  var ofd = fs.openFiles[fd];
  if (!ofd) {
    callback(new Errors.EBADF());
  }
  else {
    fgetxattr_file(context, ofd, name, standard_check_result_cb(callback));
  }
}

function setxattr(fs, context, path, name, value, flag, callback) {
  if(typeof flag === 'function') {
    callback = flag;
    flag = null;
  }

  if (!pathCheck(path, callback)) return;
  setxattr_file(context, path, name, value, flag, standard_check_result_cb(callback));
}

function fsetxattr(fs, context, fd, name, value, flag, callback) {
  if(typeof flag === 'function') {
    callback = flag;
    flag = null;
  }

  var ofd = fs.openFiles[fd];
  if (!ofd) {
    callback(new Errors.EBADF());
  }
  else if (!_(ofd.flags).contains(O_WRITE)) {
    callback(new Errors.EBADF('descriptor does not permit writing'));
  }
  else {
    fsetxattr_file(context, ofd, name, value, flag, standard_check_result_cb(callback));
  }
}

function removexattr(fs, context, path, name, callback) {
  if (!pathCheck(path, callback)) return;
  removexattr_file(context, path, name, standard_check_result_cb(callback));
}

function fremovexattr(fs, context, fd, name, callback) {
  var ofd = fs.openFiles[fd];
  if (!ofd) {
    callback(new Errors.EBADF());
  }
  else if (!_(ofd.flags).contains(O_WRITE)) {
    callback(new Errors.EBADF('descriptor does not permit writing'));
  }
  else {
    fremovexattr_file(context, ofd, name, standard_check_result_cb(callback));
  }
}

function lseek(fs, context, fd, offset, whence, callback) {
  function update_descriptor_position(error, stats) {
    if(error) {
      callback(error);
    } else {
      if(stats.size + offset < 0) {
        callback(new Errors.EINVAL('resulting file offset would be negative'));
      } else {
        ofd.position = stats.size + offset;
        callback(null, ofd.position);
      }
    }
  }

  var ofd = fs.openFiles[fd];
  if(!ofd) {
    callback(new Errors.EBADF());
  }

  if('SET' === whence) {
    if(offset < 0) {
      callback(new Errors.EINVAL('resulting file offset would be negative'));
    } else {
      ofd.position = offset;
      callback(null, ofd.position);
    }
  } else if('CUR' === whence) {
    if(ofd.position + offset < 0) {
      callback(new Errors.EINVAL('resulting file offset would be negative'));
    } else {
      ofd.position += offset;
      callback(null, ofd.position);
    }
  } else if('END' === whence) {
    fstat_file(context, ofd, update_descriptor_position);
  } else {
    callback(new Errors.EINVAL('whence argument is not a proper value'));
  }
}

function readdir(fs, context, path, callback) {
  if(!pathCheck(path, callback)) return;
  read_directory(context, path, standard_check_result_cb(callback));
}

function utimes(fs, context, path, atime, mtime, callback) {
  if(!pathCheck(path, callback)) return;

  var currentTime = Date.now();
  atime = (atime) ? atime : currentTime;
  mtime = (mtime) ? mtime : currentTime;

  utimes_file(context, path, atime, mtime, standard_check_result_cb(callback));
}

function futimes(fs, context, fd, atime, mtime, callback) {
  var currentTime = Date.now();
  atime = (atime) ? atime : currentTime;
  mtime = (mtime) ? mtime : currentTime;

  var ofd = fs.openFiles[fd];
  if(!ofd) {
    callback(new Errors.EBADF());
  } else if(!_(ofd.flags).contains(O_WRITE)) {
    callback(new Errors.EBADF('descriptor does not permit writing'));
  } else {
    futimes_file(context, ofd, atime, mtime, standard_check_result_cb(callback));
  }
}

function rename(fs, context, oldpath, newpath, callback) {
  if(!pathCheck(oldpath, callback)) return;
  if(!pathCheck(newpath, callback)) return;

  function unlink_old_node(error) {
    if(error) {
      callback(error);
    } else {
      unlink_node(context, oldpath, standard_check_result_cb(callback));
    }
  }

  link_node(context, oldpath, newpath, unlink_old_node);
}

function symlink(fs, context, srcpath, dstpath, type, callback) {
  // NOTE: we support passing the `type` arg, but ignore it.
  callback = arguments[arguments.length - 1];
  if(!pathCheck(srcpath, callback)) return;
  if(!pathCheck(dstpath, callback)) return;
  make_symbolic_link(context, srcpath, dstpath, standard_check_result_cb(callback));
}

function readlink(fs, context, path, callback) {
  if(!pathCheck(path, callback)) return;
  read_link(context, path, standard_check_result_cb(callback));
}

function lstat(fs, context, path, callback) {
  if(!pathCheck(path, callback)) return;

  function check_result(error, result) {
    if(error) {
      callback(error);
    } else {
      var stats = new Stats(result, fs.name);
      callback(null, stats);
    }
  }

  lstat_file(context, path, check_result);
}

function truncate(fs, context, path, length, callback) {
  // NOTE: length is optional
  callback = arguments[arguments.length - 1];
  length = length || 0;

  if(!pathCheck(path, callback)) return;
  truncate_file(context, path, length, standard_check_result_cb(callback));
}

function ftruncate(fs, context, fd, length, callback) {
  // NOTE: length is optional
  callback = arguments[arguments.length - 1];
  length = length || 0;

  var ofd = fs.openFiles[fd];
  if(!ofd) {
    callback(new Errors.EBADF());
  } else if(!_(ofd.flags).contains(O_WRITE)) {
    callback(new Errors.EBADF('descriptor does not permit writing'));
  } else {
    ftruncate_file(context, ofd, length, standard_check_result_cb(callback));
  }
}

module.exports = {
  ensureRootDirectory: ensure_root_directory,
  open: open,
  close: close,
  mknod: mknod,
  mkdir: mkdir,
  rmdir: rmdir,
  unlink: unlink,
  stat: stat,
  fstat: fstat,
  link: link,
  read: read,
  readFile: readFile,
  write: write,
  writeFile: writeFile,
  appendFile: appendFile,
  exists: exists,
  getxattr: getxattr,
  fgetxattr: fgetxattr,
  setxattr: setxattr,
  fsetxattr: fsetxattr,
  removexattr: removexattr,
  fremovexattr: fremovexattr,
  lseek: lseek,
  readdir: readdir,
  utimes: utimes,
  futimes: futimes,
  rename: rename,
  symlink: symlink,
  readlink: readlink,
  lstat: lstat,
  truncate: truncate,
  ftruncate: ftruncate
};

},{"../../lib/nodash.js":4,"../buffer.js":10,"../constants.js":11,"../directory-entry.js":12,"../encoding.js":13,"../errors.js":14,"../node.js":19,"../open-file-description.js":20,"../path.js":21,"../stats.js":29,"../super-node.js":30}],16:[function(_dereq_,module,exports){
var _ = _dereq_('../../lib/nodash.js');

var isNullPath = _dereq_('../path.js').isNull;
var nop = _dereq_('../shared.js').nop;

var Constants = _dereq_('../constants.js');
var FILE_SYSTEM_NAME = Constants.FILE_SYSTEM_NAME;
var FS_FORMAT = Constants.FS_FORMAT;
var FS_READY = Constants.FS_READY;
var FS_PENDING = Constants.FS_PENDING;
var FS_ERROR = Constants.FS_ERROR;
var FS_NODUPEIDCHECK = Constants.FS_NODUPEIDCHECK;

var providers = _dereq_('../providers/index.js');

var Shell = _dereq_('../shell/shell.js');
var Intercom = _dereq_('../../lib/intercom.js');
var FSWatcher = _dereq_('../fs-watcher.js');
var Errors = _dereq_('../errors.js');
var defaultGuidFn = _dereq_('../shared.js').guid;

var STDIN = Constants.STDIN;
var STDOUT = Constants.STDOUT;
var STDERR = Constants.STDERR;
var FIRST_DESCRIPTOR = Constants.FIRST_DESCRIPTOR;

// The core fs operations live on impl
var impl = _dereq_('./implementation.js');

// node.js supports a calling pattern that leaves off a callback.
function maybeCallback(callback) {
  if(typeof callback === "function") {
    return callback;
  }
  return function(err) {
    if(err) {
      throw err;
    }
  };
}

/**
 * FileSystem
 *
 * A FileSystem takes an `options` object, which can specify a number of,
 * options.  All options are optional, and include:
 *
 * name: the name of the file system, defaults to "local"
 *
 * flags: one or more flags to use when creating/opening the file system.
 *        For example: "FORMAT" will cause the file system to be formatted.
 *        No explicit flags are set by default.
 *
 * provider: an explicit storage provider to use for the file
 *           system's database context provider.  A number of context
 *           providers are included (see /src/providers), and users
 *           can write one of their own and pass it in to be used.
 *           By default an IndexedDB provider is used.
 *
 * guid: a function for generating unique IDs for nodes in the filesystem.
 *       Use this to override the built-in UUID generation. (Used mainly for tests).
 *
 * callback: a callback function to be executed when the file system becomes
 *           ready for use. Depending on the context provider used, this might
 *           be right away, or could take some time. The callback should expect
 *           an `error` argument, which will be null if everything worked.  Also
 *           users should check the file system's `readyState` and `error`
 *           properties to make sure it is usable.
 */
function FileSystem(options, callback) {
  options = options || {};
  callback = callback || nop;

  var flags = options.flags;
  var guid = options.guid ? options.guid : defaultGuidFn;
  var provider = options.provider || new providers.Default(options.name || FILE_SYSTEM_NAME);
  // If we're given a provider, match its name unless we get an explicit name
  var name = options.name || provider.name;
  var forceFormatting = _(flags).contains(FS_FORMAT);

  var fs = this;
  fs.readyState = FS_PENDING;
  fs.name = name;
  fs.error = null;

  fs.stdin = STDIN;
  fs.stdout = STDOUT;
  fs.stderr = STDERR;

  // Safely expose the list of open files and file
  // descriptor management functions
  var openFiles = {};
  var nextDescriptor = FIRST_DESCRIPTOR;
  Object.defineProperty(this, "openFiles", {
    get: function() { return openFiles; }
  });
  this.allocDescriptor = function(openFileDescription) {
    var fd = nextDescriptor ++;
    openFiles[fd] = openFileDescription;
    return fd;
  };
  this.releaseDescriptor = function(fd) {
    delete openFiles[fd];
  };

  // Safely expose the operation queue
  var queue = [];
  this.queueOrRun = function(operation) {
    var error;

    if(FS_READY == fs.readyState) {
      operation.call(fs);
    } else if(FS_ERROR == fs.readyState) {
      error = new Errors.EFILESYSTEMERROR('unknown error');
    } else {
      queue.push(operation);
    }

    return error;
  };
  function runQueued() {
    queue.forEach(function(operation) {
      operation.call(this);
    }.bind(fs));
    queue = null;
  }

  // We support the optional `options` arg from node, but ignore it
  this.watch = function(filename, options, listener) {
    if(isNullPath(filename)) {
      throw new Error('Path must be a string without null bytes.');
    }
    if(typeof options === 'function') {
      listener = options;
      options = {};
    }
    options = options || {};
    listener = listener || nop;

    var watcher = new FSWatcher();
    watcher.start(filename, false, options.recursive);
    watcher.on('change', listener);

    return watcher;
  };

  // Deal with various approaches to node ID creation
  function wrappedGuidFn(context) {
    return function(callback) {
      // Skip the duplicate ID check if asked to
      if(_(flags).contains(FS_NODUPEIDCHECK)) {
        callback(null, guid());
        return;
      }

      // Otherwise (default) make sure this id is unused first
      function guidWithCheck(callback) {
        var id = guid();
        context.getObject(id, function(err, value) {
          if(err) {
            callback(err);
            return;
          }

          // If this id is unused, use it, otherwise find another
          if(!value) {
            callback(null, id);
          } else {
            guidWithCheck(callback);
          }
        });
      }
      guidWithCheck(callback);
    };
  }

  // Let other instances (in this or other windows) know about
  // any changes to this fs instance.
  function broadcastChanges(changes) {
    if(!changes.length) {
      return;
    }
    var intercom = Intercom.getInstance();
    changes.forEach(function(change) {
      intercom.emit(change.event, change.path);
    });
  }

  // Open file system storage provider
  provider.open(function(err) {
    function complete(error) {
      function wrappedContext(methodName) {
        var context = provider[methodName]();
        context.flags = flags;
        context.changes = [];
        context.guid = wrappedGuidFn(context);

        // When the context is finished, let the fs deal with any change events
        context.close = function() {
          var changes = context.changes;
          broadcastChanges(changes);
          changes.length = 0;
        };

        return context;
      }

      // Wrap the provider so we can extend the context with fs flags and
      // an array of changes (e.g., watch event 'change' and 'rename' events
      // for paths updated during the lifetime of the context). From this
      // point forward we won't call open again, so it's safe to drop it.
      fs.provider = {
        openReadWriteContext: function() {
          return wrappedContext('getReadWriteContext');
        },
        openReadOnlyContext: function() {
          return wrappedContext('getReadOnlyContext');
        }
      };

      if(error) {
        fs.readyState = FS_ERROR;
      } else {
        fs.readyState = FS_READY;
      }
      runQueued();
      callback(error, fs);
    }

    if(err) {
      return complete(err);
    }

    var context = provider.getReadWriteContext();
    context.guid = wrappedGuidFn(context);

    // Mount the filesystem, formatting if necessary
    if(forceFormatting) {
      // Wipe the storage provider, then write root block
      context.clear(function(err) {
        if(err) {
          return complete(err);
        }
        impl.ensureRootDirectory(context, complete);
      });
    } else {
      // Use existing (or create new) root and mount
      impl.ensureRootDirectory(context, complete);
    }
  });
}

// Expose storage providers on FileSystem constructor
FileSystem.providers = providers;

/**
 * Public API for FileSystem
 */
[
  'open',
  'close',
  'mknod',
  'mkdir',
  'rmdir',
  'stat',
  'fstat',
  'link',
  'unlink',
  'read',
  'readFile',
  'write',
  'writeFile',
  'appendFile',
  'exists',
  'lseek',
  'readdir',
  'rename',
  'readlink',
  'symlink',
  'lstat',
  'truncate',
  'ftruncate',
  'utimes',
  'futimes',
  'setxattr',
  'getxattr',
  'fsetxattr',
  'fgetxattr',
  'removexattr',
  'fremovexattr'
].forEach(function(methodName) {
  FileSystem.prototype[methodName] = function() {
    var fs = this;
    var args = Array.prototype.slice.call(arguments, 0);
    var lastArgIndex = args.length - 1;

    // We may or may not get a callback, and since node.js supports
    // fire-and-forget style fs operations, we have to dance a bit here.
    var missingCallback = typeof args[lastArgIndex] !== 'function';
    var callback = maybeCallback(args[lastArgIndex]);

    var error = fs.queueOrRun(function() {
      var context = fs.provider.openReadWriteContext();

      // Fail early if the filesystem is in an error state (e.g.,
      // provider failed to open.
      if(FS_ERROR === fs.readyState) {
        var err = new Errors.EFILESYSTEMERROR('filesystem unavailable, operation canceled');
        return callback.call(fs, err);
      }

      // Wrap the callback so we can explicitly close the context
      function complete() {
        context.close();
        callback.apply(fs, arguments);
      }

      // Either add or replace the callback with our wrapper complete()
      if(missingCallback) {
        args.push(complete);
      } else {
        args[lastArgIndex] = complete;
      }

      // Forward this call to the impl's version, using the following
      // call signature, with complete() as the callback/last-arg now:
      // fn(fs, context, arg0, arg1, ... , complete);
      var fnArgs = [fs, context].concat(args);
      impl[methodName].apply(null, fnArgs);
    });
    if(error) {
      callback(error);
    }
  };
});

FileSystem.prototype.Shell = function(options) {
  return new Shell(this, options);
};

module.exports = FileSystem;

},{"../../lib/intercom.js":3,"../../lib/nodash.js":4,"../constants.js":11,"../errors.js":14,"../fs-watcher.js":17,"../path.js":21,"../providers/index.js":22,"../shared.js":26,"../shell/shell.js":28,"./implementation.js":15}],17:[function(_dereq_,module,exports){
var EventEmitter = _dereq_('../lib/eventemitter.js');
var Path = _dereq_('./path.js');
var Intercom = _dereq_('../lib/intercom.js');

/**
 * FSWatcher based on node.js' FSWatcher
 * see https://github.com/joyent/node/blob/master/lib/fs.js
 */
function FSWatcher() {
  EventEmitter.call(this);
  var self = this;
  var recursive = false;
  var recursivePathPrefix;
  var filename;

  function onchange(path) {
    // Watch for exact filename, or parent path when recursive is true.
    if(filename === path || (recursive && path.indexOf(recursivePathPrefix) === 0)) {
      self.trigger('change', 'change', path);
    }
  }

  // We support, but ignore the second arg, which node.js uses.
  self.start = function(filename_, persistent_, recursive_) {
    // Bail if we've already started (and therefore have a filename);
    if(filename) {
      return;
    }

    if(Path.isNull(filename_)) {
      throw new Error('Path must be a string without null bytes.');
    }

    // TODO: get realpath for symlinks on filename...

    // Filer's Path.normalize strips trailing slashes, which we use here.
    // See https://github.com/js-platform/filer/issues/105
    filename = Path.normalize(filename_);

    // Whether to watch beneath this path or not
    recursive = recursive_ === true;
    // If recursive, construct a path prefix portion for comparisons later
    // (i.e., '/path' becomes '/path/' so we can search within a filename for the
    // prefix). We also take care to allow for '/' on its own.
    if(recursive) {
      recursivePathPrefix = filename === '/' ? '/' : filename + '/';
    }

    var intercom = Intercom.getInstance();
    intercom.on('change', onchange);
  };

  self.close = function() {
    var intercom = Intercom.getInstance();
    intercom.off('change', onchange);
    self.removeAllListeners('change');
  };
}
FSWatcher.prototype = new EventEmitter();
FSWatcher.prototype.constructor = FSWatcher;

module.exports = FSWatcher;

},{"../lib/eventemitter.js":2,"../lib/intercom.js":3,"./path.js":21}],18:[function(_dereq_,module,exports){
module.exports = {
  FileSystem: _dereq_('./filesystem/interface.js'),
  Buffer: _dereq_('./buffer.js'),
  Path: _dereq_('./path.js'),
  Errors: _dereq_('./errors.js')
};

},{"./buffer.js":10,"./errors.js":14,"./filesystem/interface.js":16,"./path.js":21}],19:[function(_dereq_,module,exports){
var MODE_FILE = _dereq_('./constants.js').MODE_FILE;

function Node(options) {
  var now = Date.now();

  this.id = options.id;
  this.mode = options.mode || MODE_FILE;  // node type (file, directory, etc)
  this.size = options.size || 0; // size (bytes for files, entries for directories)
  this.atime = options.atime || now; // access time (will mirror ctime after creation)
  this.ctime = options.ctime || now; // creation/change time
  this.mtime = options.mtime || now; // modified time
  this.flags = options.flags || []; // file flags
  this.xattrs = options.xattrs || {}; // extended attributes
  this.nlinks = options.nlinks || 0; // links count
  this.version = options.version || 0; // node version
  this.blksize = undefined; // block size
  this.nblocks = 1; // blocks count
  this.data = options.data; // id for data object
}

// Make sure the options object has an id on property,
// either from caller or one we generate using supplied guid fn.
function ensureID(options, prop, callback) {
  if(options[prop]) {
    callback(null);
  } else {
    options.guid(function(err, id) {
      options[prop] = id;
      callback(err);
    });
  }
}

Node.create = function(options, callback) {
  // We expect both options.id and options.data to be provided/generated.
  ensureID(options, 'id', function(err) {
    if(err) {
      callback(err);
      return;
    }

    ensureID(options, 'data', function(err) {
      if(err) {
        callback(err);
        return;
      }

      callback(null, new Node(options));
    });
  });
};

module.exports = Node;

},{"./constants.js":11}],20:[function(_dereq_,module,exports){
module.exports = function OpenFileDescription(path, id, flags, position) {
  this.path = path;
  this.id = id;
  this.flags = flags;
  this.position = position;
};

},{}],21:[function(_dereq_,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// Based on https://github.com/joyent/node/blob/41e53e557992a7d552a8e23de035f9463da25c99/lib/path.js

// resolves . and .. elements in a path array with directory names there
// must be no slashes, empty elements, or device names (c:\) in the array
// (so also no leading and trailing slashes - it does not distinguish
// relative and absolute paths)
function normalizeArray(parts, allowAboveRoot) {
  // if the path tries to go above the root, `up` ends up > 0
  var up = 0;
  for (var i = parts.length - 1; i >= 0; i--) {
    var last = parts[i];
    if (last === '.') {
      parts.splice(i, 1);
    } else if (last === '..') {
      parts.splice(i, 1);
      up++;
    } else if (up) {
      parts.splice(i, 1);
      up--;
    }
  }

  // if the path is allowed to go above the root, restore leading ..s
  if (allowAboveRoot) {
    for (; up--; up) {
      parts.unshift('..');
    }
  }

  return parts;
}

// Split a filename into [root, dir, basename, ext], unix version
// 'root' is just a slash, or nothing.
var splitPathRe =
      /^(\/?)([\s\S]+\/(?!$)|\/)?((?:\.{1,2}$|[\s\S]+?)?(\.[^.\/]*)?)$/;
var splitPath = function(filename) {
  var result = splitPathRe.exec(filename);
  return [result[1] || '', result[2] || '', result[3] || '', result[4] || ''];
};

// path.resolve([from ...], to)
function resolve() {
  var resolvedPath = '',
      resolvedAbsolute = false;

  for (var i = arguments.length - 1; i >= -1 && !resolvedAbsolute; i--) {
    // XXXidbfs: we don't have process.cwd() so we use '/' as a fallback
    var path = (i >= 0) ? arguments[i] : '/';

    // Skip empty and invalid entries
    if (typeof path !== 'string' || !path) {
      continue;
    }

    resolvedPath = path + '/' + resolvedPath;
    resolvedAbsolute = path.charAt(0) === '/';
  }

  // At this point the path should be resolved to a full absolute path, but
  // handle relative paths to be safe (might happen when process.cwd() fails)

  // Normalize the path
  resolvedPath = normalizeArray(resolvedPath.split('/').filter(function(p) {
    return !!p;
  }), !resolvedAbsolute).join('/');

  return ((resolvedAbsolute ? '/' : '') + resolvedPath) || '.';
}

// path.normalize(path)
function normalize(path) {
  var isAbsolute = path.charAt(0) === '/',
      trailingSlash = path.substr(-1) === '/';

  // Normalize the path
  path = normalizeArray(path.split('/').filter(function(p) {
    return !!p;
  }), !isAbsolute).join('/');

  if (!path && !isAbsolute) {
    path = '.';
  }
  /*
   if (path && trailingSlash) {
   path += '/';
   }
   */

  return (isAbsolute ? '/' : '') + path;
}

function join() {
  var paths = Array.prototype.slice.call(arguments, 0);
  return normalize(paths.filter(function(p, index) {
    return p && typeof p === 'string';
  }).join('/'));
}

// path.relative(from, to)
function relative(from, to) {
  from = exports.resolve(from).substr(1);
  to = exports.resolve(to).substr(1);

  function trim(arr) {
    var start = 0;
    for (; start < arr.length; start++) {
      if (arr[start] !== '') break;
    }

    var end = arr.length - 1;
    for (; end >= 0; end--) {
      if (arr[end] !== '') break;
    }

    if (start > end) return [];
    return arr.slice(start, end - start + 1);
  }

  var fromParts = trim(from.split('/'));
  var toParts = trim(to.split('/'));

  var length = Math.min(fromParts.length, toParts.length);
  var samePartsLength = length;
  for (var i = 0; i < length; i++) {
    if (fromParts[i] !== toParts[i]) {
      samePartsLength = i;
      break;
    }
  }

  var outputParts = [];
  for (var i = samePartsLength; i < fromParts.length; i++) {
    outputParts.push('..');
  }

  outputParts = outputParts.concat(toParts.slice(samePartsLength));

  return outputParts.join('/');
}

function dirname(path) {
  var result = splitPath(path),
      root = result[0],
      dir = result[1];

  if (!root && !dir) {
    // No dirname whatsoever
    return '.';
  }

  if (dir) {
    // It has a dirname, strip trailing slash
    dir = dir.substr(0, dir.length - 1);
  }

  return root + dir;
}

function basename(path, ext) {
  var f = splitPath(path)[2];
  // TODO: make this comparison case-insensitive on windows?
  if (ext && f.substr(-1 * ext.length) === ext) {
    f = f.substr(0, f.length - ext.length);
  }
  // XXXidbfs: node.js just does `return f`
  return f === "" ? "/" : f;
}

function extname(path) {
  return splitPath(path)[3];
}

function isAbsolute(path) {
  if(path.charAt(0) === '/') {
    return true;
  }
  return false;
}

function isNull(path) {
  if (('' + path).indexOf('\u0000') !== -1) {
    return true;
  }
  return false;
}

// XXXidbfs: we don't support path.exists() or path.existsSync(), which
// are deprecated, and need a FileSystem instance to work. Use fs.stat().

module.exports = {
  normalize: normalize,
  resolve: resolve,
  join: join,
  relative: relative,
  sep: '/',
  delimiter: ':',
  dirname: dirname,
  basename: basename,
  extname: extname,
  isAbsolute: isAbsolute,
  isNull: isNull
};

},{}],22:[function(_dereq_,module,exports){
var IndexedDB = _dereq_('./indexeddb.js');
var WebSQL = _dereq_('./websql.js');
var Memory = _dereq_('./memory.js');

module.exports = {
  IndexedDB: IndexedDB,
  WebSQL: WebSQL,
  Memory: Memory,

  /**
   * Convenience Provider references
   */

  // The default provider to use when none is specified
  Default: IndexedDB,

  // The Fallback provider does automatic fallback checks
  Fallback: (function() {
    if(IndexedDB.isSupported()) {
      return IndexedDB;
    }

    if(WebSQL.isSupported()) {
      return WebSQL;
    }

    function NotSupported() {
      throw "[Filer Error] Your browser doesn't support IndexedDB or WebSQL.";
    }
    NotSupported.isSupported = function() {
      return false;
    };
    return NotSupported;
  }())
};

},{"./indexeddb.js":23,"./memory.js":24,"./websql.js":25}],23:[function(_dereq_,module,exports){
(function (global){
var FILE_SYSTEM_NAME = _dereq_('../constants.js').FILE_SYSTEM_NAME;
var FILE_STORE_NAME = _dereq_('../constants.js').FILE_STORE_NAME;
var IDB_RW = _dereq_('../constants.js').IDB_RW;
var IDB_RO = _dereq_('../constants.js').IDB_RO;
var Errors = _dereq_('../errors.js');
var FilerBuffer = _dereq_('../buffer.js');

var indexedDB = global.indexedDB       ||
                global.mozIndexedDB    ||
                global.webkitIndexedDB ||
                global.msIndexedDB;

function IndexedDBContext(db, mode) {
  var transaction = db.transaction(FILE_STORE_NAME, mode);
  this.objectStore = transaction.objectStore(FILE_STORE_NAME);
}

IndexedDBContext.prototype.clear = function(callback) {
  try {
    var request = this.objectStore.clear();
    request.onsuccess = function(event) {
      callback();
    };
    request.onerror = function(error) {
      callback(error);
    };
  } catch(e) {
    callback(e);
  }
};

function _get(objectStore, key, callback) {
  try {
    var request = objectStore.get(key);
    request.onsuccess = function onsuccess(event) {
      var result = event.target.result;
      callback(null, result);
    };
    request.onerror = function onerror(error) {
      callback(error);
    };
  } catch(e) {
    callback(e);
  }
}
IndexedDBContext.prototype.getObject = function(key, callback) {
  _get(this.objectStore, key, callback);
};
IndexedDBContext.prototype.getBuffer = function(key, callback) {
  _get(this.objectStore, key, function(err, arrayBuffer) {
    if(err) {
      return callback(err);
    }
    callback(null, new FilerBuffer(arrayBuffer));
  });
};

function _put(objectStore, key, value, callback) {
  try {
    var request = objectStore.put(value, key);
    request.onsuccess = function onsuccess(event) {
      var result = event.target.result;
      callback(null, result);
    };
    request.onerror = function onerror(error) {
      callback(error);
    };
  } catch(e) {
    callback(e);
  }
}
IndexedDBContext.prototype.putObject = function(key, value, callback) {
  _put(this.objectStore, key, value, callback);
};
IndexedDBContext.prototype.putBuffer = function(key, uint8BackedBuffer, callback) {
  _put(this.objectStore, key, uint8BackedBuffer.buffer, callback);
};

IndexedDBContext.prototype.delete = function(key, callback) {
  try {
    var request = this.objectStore.delete(key);
    request.onsuccess = function onsuccess(event) {
      var result = event.target.result;
      callback(null, result);
    };
    request.onerror = function(error) {
      callback(error);
    };
  } catch(e) {
    callback(e);
  }
};


function IndexedDB(name) {
  this.name = name || FILE_SYSTEM_NAME;
  this.db = null;
}
IndexedDB.isSupported = function() {
  return !!indexedDB;
};

IndexedDB.prototype.open = function(callback) {
  var that = this;

  // Bail if we already have a db open
  if(that.db) {
    return callback();
  }

  // NOTE: we're not using versioned databases.
  var openRequest = indexedDB.open(that.name);

  // If the db doesn't exist, we'll create it
  openRequest.onupgradeneeded = function onupgradeneeded(event) {
    var db = event.target.result;

    if(db.objectStoreNames.contains(FILE_STORE_NAME)) {
      db.deleteObjectStore(FILE_STORE_NAME);
    }
    db.createObjectStore(FILE_STORE_NAME);
  };

  openRequest.onsuccess = function onsuccess(event) {
    that.db = event.target.result;
    callback();
  };
  openRequest.onerror = function onerror(error) {
    callback(new Errors.EINVAL('IndexedDB cannot be accessed. If private browsing is enabled, disable it.'));
  };
};
IndexedDB.prototype.getReadOnlyContext = function() {
  // Due to timing issues in Chrome with readwrite vs. readonly indexeddb transactions
  // always use readwrite so we can make sure pending commits finish before callbacks.
  // See https://github.com/js-platform/filer/issues/128
  return new IndexedDBContext(this.db, IDB_RW);
};
IndexedDB.prototype.getReadWriteContext = function() {
  return new IndexedDBContext(this.db, IDB_RW);
};

module.exports = IndexedDB;

}).call(this,typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"../buffer.js":10,"../constants.js":11,"../errors.js":14}],24:[function(_dereq_,module,exports){
var FILE_SYSTEM_NAME = _dereq_('../constants.js').FILE_SYSTEM_NAME;
// NOTE: prefer setImmediate to nextTick for proper recursion yielding.
// see https://github.com/js-platform/filer/pull/24
var asyncCallback = _dereq_('../../lib/async.js').setImmediate;

/**
 * Make shared in-memory DBs possible when using the same name.
 */
var createDB = (function() {
  var pool = {};
  return function getOrCreate(name) {
    if(!pool.hasOwnProperty(name)) {
      pool[name] = {};
    }
    return pool[name];
  };
}());

function MemoryContext(db, readOnly) {
  this.readOnly = readOnly;
  this.objectStore = db;
}

MemoryContext.prototype.clear = function(callback) {
  if(this.readOnly) {
    asyncCallback(function() {
      callback("[MemoryContext] Error: write operation on read only context");
    });
    return;
  }
  var objectStore = this.objectStore;
  Object.keys(objectStore).forEach(function(key){
    delete objectStore[key];
  });
  asyncCallback(callback);
};

// Memory context doesn't care about differences between Object and Buffer
MemoryContext.prototype.getObject =
MemoryContext.prototype.getBuffer =
function(key, callback) {
  var that = this;
  asyncCallback(function() {
    callback(null, that.objectStore[key]);
  });
};
MemoryContext.prototype.putObject =
MemoryContext.prototype.putBuffer =
function(key, value, callback) {
  if(this.readOnly) {
    asyncCallback(function() {
      callback("[MemoryContext] Error: write operation on read only context");
    });
    return;
  }
  this.objectStore[key] = value;
  asyncCallback(callback);
};

MemoryContext.prototype.delete = function(key, callback) {
  if(this.readOnly) {
    asyncCallback(function() {
      callback("[MemoryContext] Error: write operation on read only context");
    });
    return;
  }
  delete this.objectStore[key];
  asyncCallback(callback);
};


function Memory(name) {
  this.name = name || FILE_SYSTEM_NAME;
}
Memory.isSupported = function() {
  return true;
};

Memory.prototype.open = function(callback) {
  this.db = createDB(this.name);
  asyncCallback(callback);
};
Memory.prototype.getReadOnlyContext = function() {
  return new MemoryContext(this.db, true);
};
Memory.prototype.getReadWriteContext = function() {
  return new MemoryContext(this.db, false);
};

module.exports = Memory;

},{"../../lib/async.js":1,"../constants.js":11}],25:[function(_dereq_,module,exports){
(function (global){
var FILE_SYSTEM_NAME = _dereq_('../constants.js').FILE_SYSTEM_NAME;
var FILE_STORE_NAME = _dereq_('../constants.js').FILE_STORE_NAME;
var WSQL_VERSION = _dereq_('../constants.js').WSQL_VERSION;
var WSQL_SIZE = _dereq_('../constants.js').WSQL_SIZE;
var WSQL_DESC = _dereq_('../constants.js').WSQL_DESC;
var Errors = _dereq_('../errors.js');
var FilerBuffer = _dereq_('../buffer.js');
var base64ArrayBuffer = _dereq_('base64-arraybuffer');

function WebSQLContext(db, isReadOnly) {
  var that = this;
  this.getTransaction = function(callback) {
    if(that.transaction) {
      callback(that.transaction);
      return;
    }
    // Either do readTransaction() (read-only) or transaction() (read/write)
    db[isReadOnly ? 'readTransaction' : 'transaction'](function(transaction) {
      that.transaction = transaction;
      callback(transaction);
    });
  };
}

WebSQLContext.prototype.clear = function(callback) {
  function onError(transaction, error) {
    callback(error);
  }
  function onSuccess(transaction, result) {
    callback(null);
  }
  this.getTransaction(function(transaction) {
    transaction.executeSql("DELETE FROM " + FILE_STORE_NAME + ";",
                           [], onSuccess, onError);
  });
};

function _get(getTransaction, key, callback) {
  function onSuccess(transaction, result) {
    // If the key isn't found, return null
    var value = result.rows.length === 0 ? null : result.rows.item(0).data;
    callback(null, value);
  }
  function onError(transaction, error) {
    callback(error);
  }
  getTransaction(function(transaction) {
    transaction.executeSql("SELECT data FROM " + FILE_STORE_NAME + " WHERE id = ? LIMIT 1;",
                           [key], onSuccess, onError);
  });
}
WebSQLContext.prototype.getObject = function(key, callback) {
  _get(this.getTransaction, key, function(err, result) {
    if(err) {
      return callback(err);
    }

    try {
      if(result) {
        result = JSON.parse(result);
      }
    } catch(e) {
      return callback(e);
    }

    callback(null, result);
  });
};
WebSQLContext.prototype.getBuffer = function(key, callback) {
  _get(this.getTransaction, key, function(err, result) {
    if(err) {
      return callback(err);
    }

    // Deal with zero-length ArrayBuffers, which will be encoded as ''
    if(result || result === '') {
      var arrayBuffer = base64ArrayBuffer.decode(result);
      result = new FilerBuffer(arrayBuffer);
    }

    callback(null, result);
  });
};

function _put(getTransaction, key, value, callback) {
  function onSuccess(transaction, result) {
    callback(null);
  }
  function onError(transaction, error) {
    callback(error);
  }
  getTransaction(function(transaction) {
    transaction.executeSql("INSERT OR REPLACE INTO " + FILE_STORE_NAME + " (id, data) VALUES (?, ?);",
                           [key, value], onSuccess, onError);
  });
}
WebSQLContext.prototype.putObject = function(key, value, callback) {
  var json = JSON.stringify(value);
  _put(this.getTransaction, key, json, callback);
};
WebSQLContext.prototype.putBuffer = function(key, uint8BackedBuffer, callback) {
  var base64 = base64ArrayBuffer.encode(uint8BackedBuffer.buffer);
  _put(this.getTransaction, key, base64, callback);
};

WebSQLContext.prototype.delete = function(key, callback) {
  function onSuccess(transaction, result) {
    callback(null);
  }
  function onError(transaction, error) {
    callback(error);
  }
  this.getTransaction(function(transaction) {
    transaction.executeSql("DELETE FROM " + FILE_STORE_NAME + " WHERE id = ?;",
                           [key], onSuccess, onError);
  });
};


function WebSQL(name) {
  this.name = name || FILE_SYSTEM_NAME;
  this.db = null;
}
WebSQL.isSupported = function() {
  return !!global.openDatabase;
};

WebSQL.prototype.open = function(callback) {
  var that = this;

  // Bail if we already have a db open
  if(that.db) {
    return callback();
  }

  var db = global.openDatabase(that.name, WSQL_VERSION, WSQL_DESC, WSQL_SIZE);
  if(!db) {
    callback("[WebSQL] Unable to open database.");
    return;
  }

  function onError(transaction, error) {
    if (error.code === 5) {
      callback(new Errors.EINVAL('WebSQL cannot be accessed. If private browsing is enabled, disable it.'));
    }
    callback(error);
  }
  function onSuccess(transaction, result) {
    that.db = db;
    callback();
  }

  // Create the table and index we'll need to store the fs data.
  db.transaction(function(transaction) {
    function createIndex(transaction) {
      transaction.executeSql("CREATE INDEX IF NOT EXISTS idx_" + FILE_STORE_NAME + "_id" +
                             " on " + FILE_STORE_NAME + " (id);",
                             [], onSuccess, onError);
    }
    transaction.executeSql("CREATE TABLE IF NOT EXISTS " + FILE_STORE_NAME + " (id unique, data TEXT);",
                           [], createIndex, onError);
  });
};
WebSQL.prototype.getReadOnlyContext = function() {
  return new WebSQLContext(this.db, true);
};
WebSQL.prototype.getReadWriteContext = function() {
  return new WebSQLContext(this.db, false);
};

module.exports = WebSQL;

}).call(this,typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"../buffer.js":10,"../constants.js":11,"../errors.js":14,"base64-arraybuffer":5}],26:[function(_dereq_,module,exports){
function guid() {
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
    var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8);
    return v.toString(16);
  }).toUpperCase();
}

function nop() {}

/**
 * Convert a Uint8Array to a regular array
 */
function u8toArray(u8) {
  var array = [];
  var len = u8.length;
  for(var i = 0; i < len; i++) {
    array[i] = u8[i];
  }
  return array;
}

module.exports = {
  guid: guid,
  u8toArray: u8toArray,
  nop: nop
};

},{}],27:[function(_dereq_,module,exports){
var defaults = _dereq_('../constants.js').ENVIRONMENT;

module.exports = function Environment(env) {
  env = env || {};
  env.TMP = env.TMP || defaults.TMP;
  env.PATH = env.PATH || defaults.PATH;

  this.get = function(name) {
    return env[name];
  };

  this.set = function(name, value) {
    env[name] = value;
  };
};

},{"../constants.js":11}],28:[function(_dereq_,module,exports){
var Path = _dereq_('../path.js');
var Errors = _dereq_('../errors.js');
var Environment = _dereq_('./environment.js');
var async = _dereq_('../../lib/async.js');
var Encoding = _dereq_('../encoding.js');

function Shell(fs, options) {
  options = options || {};

  var env = new Environment(options.env);
  var cwd = '/';

  /**
   * The bound FileSystem (cannot be changed)
   */
  Object.defineProperty(this, 'fs', {
    get: function() { return fs; },
    enumerable: true
  });

  /**
   * The shell's environment (e.g., for things like
   * path, tmp, and other env vars). Use env.get()
   * and env.set() to work with variables.
   */
  Object.defineProperty(this, 'env', {
    get: function() { return env; },
    enumerable: true
  });

  /**
   * Change the current working directory. We
   * include `cd` on the `this` vs. proto so that
   * we can access cwd without exposing it externally.
   */
  this.cd = function(path, callback) {
    path = Path.resolve(cwd, path);
    // Make sure the path actually exists, and is a dir
    fs.stat(path, function(err, stats) {
      if(err) {
        callback(new Errors.ENOTDIR(null, path));
        return;
      }
      if(stats.type === 'DIRECTORY') {
        cwd = path;
        callback();
      } else {
        callback(new Errors.ENOTDIR(null, path));
      }
    });
  };

  /**
   * Get the current working directory (changed with `cd()`)
   */
  this.pwd = function() {
    return cwd;
  };
}

/**
 * Execute the .js command located at `path`. Such commands
 * should assume the existence of 3 arguments, which will be
 * defined at runtime:
 *
 *   * fs - the current shell's bound filesystem object
 *   * args - a list of arguments for the command, or an empty list if none
 *   * callback - a callback function(error, result) to call when done.
 *
 * The .js command's contents should be the body of a function
 * that looks like this:
 *
 * function(fs, args, callback) {
 *   // .js code here
 * }
 */
Shell.prototype.exec = function(path, args, callback) {
  /* jshint evil:true */
  var sh = this;
  var fs = sh.fs;
  if(typeof args === 'function') {
    callback = args;
    args = [];
  }
  args = args || [];
  callback = callback || function(){};
  path = Path.resolve(sh.pwd(), path);

  fs.readFile(path, "utf8", function(error, data) {
    if(error) {
      callback(error);
      return;
    }
    try {
      var cmd = new Function('fs', 'args', 'callback', data);
      cmd(fs, args, callback);
    } catch(e) {
      callback(e);
    }
  });
};

/**
 * Create a file if it does not exist, or update access and
 * modified times if it does. Valid options include:
 *
 *  * updateOnly - whether to create the file if missing (defaults to false)
 *  * date - use the provided Date value instead of current date/time
 */
Shell.prototype.touch = function(path, options, callback) {
  var sh = this;
  var fs = sh.fs;
  if(typeof options === 'function') {
    callback = options;
    options = {};
  }
  options = options || {};
  callback = callback || function(){};
  path = Path.resolve(sh.pwd(), path);

  function createFile(path) {
    fs.writeFile(path, '', callback);
  }

  function updateTimes(path) {
    var now = Date.now();
    var atime = options.date || now;
    var mtime = options.date || now;

    fs.utimes(path, atime, mtime, callback);
  }

  fs.stat(path, function(error, stats) {
    if(error) {
      if(options.updateOnly === true) {
        callback();
      } else {
        createFile(path);
      }
    } else {
      updateTimes(path);
    }
  });
};

/**
 * Concatenate multiple files into a single String, with each
 * file separated by a newline. The `files` argument should
 * be a String (path to single file) or an Array of Strings
 * (multiple file paths).
 */
Shell.prototype.cat = function(files, callback) {
  var sh = this;
  var fs = sh.fs;
  var all = '';
  callback = callback || function(){};

  if(!files) {
    callback(new Errors.EINVAL('Missing files argument'));
    return;
  }

  files = typeof files === 'string' ? [ files ] : files;

  function append(item, callback) {
    var filename = Path.resolve(sh.pwd(), item);
    fs.readFile(filename, 'utf8', function(error, data) {
      if(error) {
        callback(error);
        return;
      }
      all += data + '\n';
      callback();
    });
  }

  async.eachSeries(files, append, function(error) {
    if(error) {
      callback(error);
    } else {
      callback(null, all.replace(/\n$/, ''));
    }
  });
};

/**
 * Get the listing of a directory, returning an array of
 * file entries in the following form:
 *
 * {
 *   path: <String> the basename of the directory entry
 *   links: <Number> the number of links to the entry
 *   size: <Number> the size in bytes of the entry
 *   modified: <Number> the last modified date/time
 *   type: <String> the type of the entry
 *   contents: <Array> an optional array of child entries
 * }
 *
 * By default ls() gives a shallow listing. If you want
 * to follow directories as they are encountered, use
 * the `recursive=true` option.
 */
Shell.prototype.ls = function(dir, options, callback) {
  var sh = this;
  var fs = sh.fs;
  if(typeof options === 'function') {
    callback = options;
    options = {};
  }
  options = options || {};
  callback = callback || function(){};

  if(!dir) {
    callback(new Errors.EINVAL('Missing dir argument'));
    return;
  }

  function list(path, callback) {
    var pathname = Path.resolve(sh.pwd(), path);
    var result = [];

    fs.readdir(pathname, function(error, entries) {
      if(error) {
        callback(error);
        return;
      }

      function getDirEntry(name, callback) {
        name = Path.join(pathname, name);
        fs.stat(name, function(error, stats) {
          if(error) {
            callback(error);
            return;
          }
          var entry = {
            path: Path.basename(name),
            links: stats.nlinks,
            size: stats.size,
            modified: stats.mtime,
            type: stats.type
          };

          if(options.recursive && stats.type === 'DIRECTORY') {
            list(Path.join(pathname, entry.path), function(error, items) {
              if(error) {
                callback(error);
                return;
              }
              entry.contents = items;
              result.push(entry);
              callback();
            });
          } else {
            result.push(entry);
            callback();
          }
        });
      }

      async.eachSeries(entries, getDirEntry, function(error) {
        callback(error, result);
      });
    });
  }

  list(dir, callback);
};

/**
 * Removes the file or directory at `path`. If `path` is a file
 * it will be removed. If `path` is a directory, it will be
 * removed if it is empty, otherwise the callback will receive
 * an error. In order to remove non-empty directories, use the
 * `recursive=true` option.
 */
Shell.prototype.rm = function(path, options, callback) {
  var sh = this;
  var fs = sh.fs;
  if(typeof options === 'function') {
    callback = options;
    options = {};
  }
  options = options || {};
  callback = callback || function(){};

  if(!path) {
    callback(new Errors.EINVAL('Missing path argument'));
    return;
  }

  function remove(pathname, callback) {
    pathname = Path.resolve(sh.pwd(), pathname);
    fs.stat(pathname, function(error, stats) {
      if(error) {
        callback(error);
        return;
      }

      // If this is a file, delete it and we're done
      if(stats.type === 'FILE') {
        fs.unlink(pathname, callback);
        return;
      }

      // If it's a dir, check if it's empty
      fs.readdir(pathname, function(error, entries) {
        if(error) {
          callback(error);
          return;
        }

        // If dir is empty, delete it and we're done
        if(entries.length === 0) {
          fs.rmdir(pathname, callback);
          return;
        }

        // If not, see if we're allowed to delete recursively
        if(!options.recursive) {
          callback(new Errors.ENOTEMPTY(null, pathname));
          return;
        }

        // Remove each dir entry recursively, then delete the dir.
        entries = entries.map(function(filename) {
          // Root dir entries absolutely
          return Path.join(pathname, filename);
        });
        async.eachSeries(entries, remove, function(error) {
          if(error) {
            callback(error);
            return;
          }
          fs.rmdir(pathname, callback);
        });
      });
    });
  }

  remove(path, callback);
};

/**
 * Gets the path to the temporary directory, creating it if not
 * present. The directory used is the one specified in
 * env.TMP. The callback receives (error, tempDirName).
 */
Shell.prototype.tempDir = function(callback) {
  var sh = this;
  var fs = sh.fs;
  var tmp = sh.env.get('TMP');
  callback = callback || function(){};

  // Try and create it, and it will either work or fail
  // but either way it's now there.
  fs.mkdir(tmp, function(err) {
    callback(null, tmp);
  });
};

/**
 * Recursively creates the directory at `path`. If the parent
 * of `path` does not exist, it will be created.
 * Based off EnsureDir by Sam X. Xu
 * https://www.npmjs.org/package/ensureDir
 * MIT License
 */
Shell.prototype.mkdirp = function(path, callback) {
  var sh = this;
  var fs = sh.fs;
  callback = callback || function(){};

  if(!path) {
    callback(new Errors.EINVAL('Missing path argument'));
    return;
  }
  else if (path === '/') {
    callback();
    return;
  }
  function _mkdirp(path, callback) {
    fs.stat(path, function (err, stat) {
      if(stat) {
        if(stat.isDirectory()) {
          callback();
          return;
        }
        else if (stat.isFile()) {
          callback(new Errors.ENOTDIR(null, path));
          return;
        }
      }
      else if (err && err.code !== 'ENOENT') {
        callback(err);
        return;
      }
      else {
        var parent = Path.dirname(path);
        if(parent === '/') {
          fs.mkdir(path, function (err) {
            if (err && err.code != 'EEXIST') {
              callback(err);
              return;
            }
            callback();
            return;
          });
        }
        else {
          _mkdirp(parent, function (err) {
            if (err) return callback(err);
            fs.mkdir(path, function (err) {
              if (err && err.code != 'EEXIST') {
                callback(err);
                return;
              }
              callback();
              return;
            });
          });
        }
      }
    });
  }

  _mkdirp(path, callback);
};

module.exports = Shell;

},{"../../lib/async.js":1,"../encoding.js":13,"../errors.js":14,"../path.js":21,"./environment.js":27}],29:[function(_dereq_,module,exports){
var Constants = _dereq_('./constants.js');

function Stats(fileNode, devName) {
  this.node = fileNode.id;
  this.dev = devName;
  this.size = fileNode.size;
  this.nlinks = fileNode.nlinks;
  this.atime = fileNode.atime;
  this.mtime = fileNode.mtime;
  this.ctime = fileNode.ctime;
  this.type = fileNode.mode;
}

Stats.prototype.isFile = function() {
  return this.type === Constants.MODE_FILE;
};

Stats.prototype.isDirectory = function() {
  return this.type === Constants.MODE_DIRECTORY;
};

Stats.prototype.isSymbolicLink = function() {
  return this.type === Constants.MODE_SYMBOLIC_LINK;
};

// These will always be false in Filer.
Stats.prototype.isSocket          =
Stats.prototype.isFIFO            =
Stats.prototype.isCharacterDevice =
Stats.prototype.isBlockDevice     =
function() {
  return false;
};

module.exports = Stats;

},{"./constants.js":11}],30:[function(_dereq_,module,exports){
var Constants = _dereq_('./constants.js');

function SuperNode(options) {
  var now = Date.now();

  this.id = Constants.SUPER_NODE_ID;
  this.mode = Constants.MODE_META;
  this.atime = options.atime || now;
  this.ctime = options.ctime || now;
  this.mtime = options.mtime || now;
  // root node id (randomly generated)
  this.rnode = options.rnode;
}

SuperNode.create = function(options, callback) {
  options.guid(function(err, rnode) {
    if(err) {
      callback(err);
      return;
    }
    options.rnode = options.rnode || rnode;
    callback(null, new SuperNode(options));
  });
};

module.exports = SuperNode;

},{"./constants.js":11}]},{},[18])
(18)
});