// 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.

// Maintainers, keep in mind that octal literals are not allowed
// in strict mode. Use the decimal value and add a comment with
// the octal value. Example:
//
//   var mode = 438; /* mode=0666 */

var util = require('util');
var pathModule = require('path');

var binding = process.binding('fs');
var constants = process.binding('constants');
var fs = exports;
var Stream = require('stream').Stream;
var EventEmitter = require('events').EventEmitter;

var Readable = require('./lib/_stream_readable.js');
var Writable = require('./lib/_stream_writable.js');

var kMinPoolSpace = 128;
var kPoolSize = 40 * 1024;

var O_APPEND = constants.O_APPEND || 0;
var O_CREAT = constants.O_CREAT || 0;
var O_DIRECTORY = constants.O_DIRECTORY || 0;
var O_EXCL = constants.O_EXCL || 0;
var O_NOCTTY = constants.O_NOCTTY || 0;
var O_NOFOLLOW = constants.O_NOFOLLOW || 0;
var O_RDONLY = constants.O_RDONLY || 0;
var O_RDWR = constants.O_RDWR || 0;
var O_SYMLINK = constants.O_SYMLINK || 0;
var O_SYNC = constants.O_SYNC || 0;
var O_TRUNC = constants.O_TRUNC || 0;
var O_WRONLY = constants.O_WRONLY || 0;

var isWindows = process.platform === 'win32';

var DEBUG = process.env.NODE_DEBUG && /fs/.test(process.env.NODE_DEBUG);

function rethrow() {
  // Only enable in debug mode. A backtrace uses ~1000 bytes of heap space and
  // is fairly slow to generate.
  if (DEBUG) {
    var backtrace = new Error;
    return function(err) {
      if (err) {
        backtrace.message = err.message;
        err = backtrace;
        throw err;
      }
    };
  }

  return function(err) {
    if (err) {
      throw err;  // Forgot a callback but don't know where? Use NODE_DEBUG=fs
    }
  };
}

function maybeCallback(cb) {
  return typeof cb === 'function' ? cb : rethrow();
}

// Ensure that callbacks run in the global context. Only use this function
// for callbacks that are passed to the binding layer, callbacks that are
// invoked from JS already run in the proper scope.
function makeCallback(cb) {
  if (typeof cb !== 'function') {
    return rethrow();
  }

  return function() {
    return cb.apply(null, arguments);
  };
}

function assertEncoding(encoding) {
  if (encoding && !Buffer.isEncoding(encoding)) {
    throw new Error('Unknown encoding: ' + encoding);
  }
}

function nullCheck(path, callback) {
  if (('' + path).indexOf('\u0000') !== -1) {
    var er = new Error('Path must be a string without null bytes.');
    if (!callback)
      throw er;
    process.nextTick(function() {
      callback(er);
    });
    return false;
  }
  return true;
}

fs.Stats = binding.Stats;

fs.Stats.prototype._checkModeProperty = function(property) {
  return ((this.mode & constants.S_IFMT) === property);
};

fs.Stats.prototype.isDirectory = function() {
  return this._checkModeProperty(constants.S_IFDIR);
};

fs.Stats.prototype.isFile = function() {
  return this._checkModeProperty(constants.S_IFREG);
};

fs.Stats.prototype.isBlockDevice = function() {
  return this._checkModeProperty(constants.S_IFBLK);
};

fs.Stats.prototype.isCharacterDevice = function() {
  return this._checkModeProperty(constants.S_IFCHR);
};

fs.Stats.prototype.isSymbolicLink = function() {
  return this._checkModeProperty(constants.S_IFLNK);
};

fs.Stats.prototype.isFIFO = function() {
  return this._checkModeProperty(constants.S_IFIFO);
};

fs.Stats.prototype.isSocket = function() {
  return this._checkModeProperty(constants.S_IFSOCK);
};

fs.exists = function(path, callback) {
  if (!nullCheck(path, cb)) return;
  binding.stat(pathModule._makeLong(path), cb);
  function cb(err, stats) {
    if (callback) callback(err ? false : true);
  }
};

fs.existsSync = function(path) {
  try {
    nullCheck(path);
    binding.stat(pathModule._makeLong(path));
    return true;
  } catch (e) {
    return false;
  }
};

fs.readFile = function(path, encoding_) {
  var encoding = typeof(encoding_) === 'string' ? encoding_ : null;
  var callback = maybeCallback(arguments[arguments.length - 1]);

  assertEncoding(encoding);

  // first, stat the file, so we know the size.
  var size;
  var buffer; // single buffer with file data
  var buffers; // list for when size is unknown
  var pos = 0;
  var fd;

  fs.open(path, constants.O_RDONLY, 438 /*=0666*/, function(er, fd_) {
    if (er) return callback(er);
    fd = fd_;

    fs.fstat(fd, function(er, st) {
      if (er) return callback(er);
      size = st.size;
      if (size === 0) {
        // the kernel lies about many files.
        // Go ahead and try to read some bytes.
        buffers = [];
        return read();
      }

      buffer = new Buffer(size);
      read();
    });
  });

  function read() {
    if (size === 0) {
      buffer = new Buffer(8192);
      fs.read(fd, buffer, 0, 8192, -1, afterRead);
    } else {
      fs.read(fd, buffer, pos, size - pos, -1, afterRead);
    }
  }

  function afterRead(er, bytesRead) {
    if (er) {
      return fs.close(fd, function(er2) {
        return callback(er);
      });
    }

    if (bytesRead === 0) {
      return close();
    }

    pos += bytesRead;
    if (size !== 0) {
      if (pos === size) close();
      else read();
    } else {
      // unknown size, just read until we don't get bytes.
      buffers.push(buffer.slice(0, bytesRead));
      read();
    }
  }

  function close() {
    fs.close(fd, function(er) {
      if (size === 0) {
        // collected the data into the buffers list.
        buffer = Buffer.concat(buffers, pos);
      } else if (pos < size) {
        buffer = buffer.slice(0, pos);
      }

      if (encoding) buffer = buffer.toString(encoding);
      return callback(er, buffer);
    });
  }
};

fs.readFileSync = function(path, encoding) {
  assertEncoding(encoding);

  var fd = fs.openSync(path, constants.O_RDONLY, 438 /*=0666*/);

  var size;
  var threw = true;
  try {
    size = fs.fstatSync(fd).size;
    threw = false;
  } finally {
    if (threw) fs.closeSync(fd);
  }

  var pos = 0;
  var buffer; // single buffer with file data
  var buffers; // list for when size is unknown

  if (size === 0) {
    buffers = [];
  } else {
    buffer = new Buffer(size);
  }

  var done = false;
  while (!done) {
    var threw = true;
    try {
      if (size !== 0) {
        var bytesRead = fs.readSync(fd, buffer, pos, size - pos);
      } else {
        // the kernel lies about many files.
        // Go ahead and try to read some bytes.
        buffer = new Buffer(8192);
        var bytesRead = fs.readSync(fd, buffer, 0, 8192);
        if (bytesRead) {
          buffers.push(buffer.slice(0, bytesRead));
        }
      }
      threw = false;
    } finally {
      if (threw) fs.closeSync(fd);
    }

    pos += bytesRead;
    done = (bytesRead === 0) || (size !== 0 && pos >= size);
  }

  fs.closeSync(fd);

  if (size === 0) {
    // data was collected into the buffers list.
    buffer = Buffer.concat(buffers, pos);
  } else if (pos < size) {
    buffer = buffer.slice(0, pos);
  }

  if (encoding) buffer = buffer.toString(encoding);
  return buffer;
};

// Used by binding.open and friends
function stringToFlags(flag) {
  // Only mess with strings
  if (typeof flag !== 'string') {
    return flag;
  }

  // O_EXCL is mandated by POSIX, Windows supports it too.
  // Let's add a check anyway, just in case.
  if (!O_EXCL && ~flag.indexOf('x')) {
    throw errnoException('ENOSYS', 'fs.open(O_EXCL)');
  }

  switch (flag) {
    case 'r' : return O_RDONLY;
    case 'rs' : return O_RDONLY | O_SYNC;
    case 'r+' : return O_RDWR;
    case 'rs+' : return O_RDWR | O_SYNC;

    case 'w' : return O_TRUNC | O_CREAT | O_WRONLY;
    case 'wx' : // fall through
    case 'xw' : return O_TRUNC | O_CREAT | O_WRONLY | O_EXCL;

    case 'w+' : return O_TRUNC | O_CREAT | O_RDWR;
    case 'wx+': // fall through
    case 'xw+': return O_TRUNC | O_CREAT | O_RDWR | O_EXCL;

    case 'a' : return O_APPEND | O_CREAT | O_WRONLY;
    case 'ax' : // fall through
    case 'xa' : return O_APPEND | O_CREAT | O_WRONLY | O_EXCL;

    case 'a+' : return O_APPEND | O_CREAT | O_RDWR;
    case 'ax+': // fall through
    case 'xa+': return O_APPEND | O_CREAT | O_RDWR | O_EXCL;
  }

  throw new Error('Unknown file open flag: ' + flag);
}

// exported but hidden, only used by test/simple/test-fs-open-flags.js
Object.defineProperty(exports, '_stringToFlags', {
  enumerable: false,
  value: stringToFlags
});

// Yes, the follow could be easily DRYed up but I provide the explicit
// list to make the arguments clear.

fs.close = function(fd, callback) {
  binding.close(fd, makeCallback(callback));
};

fs.closeSync = function(fd) {
  return binding.close(fd);
};

function modeNum(m, def) {
  switch (typeof m) {
    case 'number': return m;
    case 'string': return parseInt(m, 8);
    default:
      if (def) {
        return modeNum(def);
      } else {
        return undefined;
      }
  }
}

fs.open = function(path, flags, mode, callback) {
  callback = makeCallback(arguments[arguments.length - 1]);
  mode = modeNum(mode, 438 /*=0666*/);

  if (!nullCheck(path, callback)) return;
  binding.open(pathModule._makeLong(path),
               stringToFlags(flags),
               mode,
               callback);
};

fs.openSync = function(path, flags, mode) {
  mode = modeNum(mode, 438 /*=0666*/);
  nullCheck(path);
  return binding.open(pathModule._makeLong(path), stringToFlags(flags), mode);
};

fs.read = function(fd, buffer, offset, length, position, callback) {
  if (!Buffer.isBuffer(buffer)) {
    // legacy string interface (fd, length, position, encoding, callback)
    var cb = arguments[4],
        encoding = arguments[3];

    assertEncoding(encoding);

    position = arguments[2];
    length = arguments[1];
    buffer = new Buffer(length);
    offset = 0;

    callback = function(err, bytesRead) {
      if (!cb) return;

      var str = (bytesRead > 0) ? buffer.toString(encoding, 0, bytesRead) : '';

      (cb)(err, str, bytesRead);
    };
  }

  function wrapper(err, bytesRead) {
    // Retain a reference to buffer so that it can't be GC'ed too soon.
    callback && callback(err, bytesRead || 0, buffer);
  }

  binding.read(fd, buffer, offset, length, position, wrapper);
};

fs.readSync = function(fd, buffer, offset, length, position) {
  var legacy = false;
  if (!Buffer.isBuffer(buffer)) {
    // legacy string interface (fd, length, position, encoding, callback)
    legacy = true;
    var encoding = arguments[3];

    assertEncoding(encoding);

    position = arguments[2];
    length = arguments[1];
    buffer = new Buffer(length);

    offset = 0;
  }

  var r = binding.read(fd, buffer, offset, length, position);
  if (!legacy) {
    return r;
  }

  var str = (r > 0) ? buffer.toString(encoding, 0, r) : '';
  return [str, r];
};

fs.write = function(fd, buffer, offset, length, position, callback) {
  if (!Buffer.isBuffer(buffer)) {
    // legacy string interface (fd, data, position, encoding, callback)
    callback = arguments[4];
    position = arguments[2];
    assertEncoding(arguments[3]);

    buffer = new Buffer('' + arguments[1], arguments[3]);
    offset = 0;
    length = buffer.length;
  }

  if (!length) {
    if (typeof callback == 'function') {
      process.nextTick(function() {
        callback(undefined, 0);
      });
    }
    return;
  }

  callback = maybeCallback(callback);

  function wrapper(err, written) {
    // Retain a reference to buffer so that it can't be GC'ed too soon.
    callback(err, written || 0, buffer);
  }

  binding.write(fd, buffer, offset, length, position, wrapper);
};

fs.writeSync = function(fd, buffer, offset, length, position) {
  if (!Buffer.isBuffer(buffer)) {
    // legacy string interface (fd, data, position, encoding)
    position = arguments[2];
    assertEncoding(arguments[3]);

    buffer = new Buffer('' + arguments[1], arguments[3]);
    offset = 0;
    length = buffer.length;
  }
  if (!length) return 0;

  return binding.write(fd, buffer, offset, length, position);
};

fs.rename = function(oldPath, newPath, callback) {
  callback = makeCallback(callback);
  if (!nullCheck(oldPath, callback)) return;
  if (!nullCheck(newPath, callback)) return;
  binding.rename(pathModule._makeLong(oldPath),
                 pathModule._makeLong(newPath),
                 callback);
};

fs.renameSync = function(oldPath, newPath) {
  nullCheck(oldPath);
  nullCheck(newPath);
  return binding.rename(pathModule._makeLong(oldPath),
                        pathModule._makeLong(newPath));
};

fs.truncate = function(path, len, callback) {
  if (typeof path === 'number') {
    // legacy
    return fs.ftruncate(path, len, callback);
  }
  if (typeof len === 'function') {
    callback = len;
    len = 0;
  } else if (typeof len === 'undefined') {
    len = 0;
  }
  callback = maybeCallback(callback);
  fs.open(path, 'w', function(er, fd) {
    if (er) return callback(er);
    binding.ftruncate(fd, len, function(er) {
      fs.close(fd, function(er2) {
        callback(er || er2);
      });
    });
  });
};

fs.truncateSync = function(path, len) {
  if (typeof path === 'number') {
    // legacy
    return fs.ftruncateSync(path, len);
  }
  if (typeof len === 'undefined') {
    len = 0;
  }
  // allow error to be thrown, but still close fd.
  var fd = fs.openSync(path, 'w');
  try {
    var ret = fs.ftruncateSync(fd, len);
  } finally {
    fs.closeSync(fd);
  }
  return ret;
};

fs.ftruncate = function(fd, len, callback) {
  if (typeof len === 'function') {
    callback = len;
    len = 0;
  } else if (typeof len === 'undefined') {
    len = 0;
  }
  binding.ftruncate(fd, len, makeCallback(callback));
};

fs.ftruncateSync = function(fd, len) {
  if (typeof len === 'undefined') {
    len = 0;
  }
  return binding.ftruncate(fd, len);
};

fs.rmdir = function(path, callback) {
  callback = makeCallback(callback);
  if (!nullCheck(path, callback)) return;
  binding.rmdir(pathModule._makeLong(path), callback);
};

fs.rmdirSync = function(path) {
  nullCheck(path);
  return binding.rmdir(pathModule._makeLong(path));
};

fs.fdatasync = function(fd, callback) {
  binding.fdatasync(fd, makeCallback(callback));
};

fs.fdatasyncSync = function(fd) {
  return binding.fdatasync(fd);
};

fs.fsync = function(fd, callback) {
  binding.fsync(fd, makeCallback(callback));
};

fs.fsyncSync = function(fd) {
  return binding.fsync(fd);
};

fs.mkdir = function(path, mode, callback) {
  if (typeof mode === 'function') callback = mode;
  callback = makeCallback(callback);
  if (!nullCheck(path, callback)) return;
  binding.mkdir(pathModule._makeLong(path),
                modeNum(mode, 511 /*=0777*/),
                callback);
};

fs.mkdirSync = function(path, mode) {
  nullCheck(path);
  return binding.mkdir(pathModule._makeLong(path),
                       modeNum(mode, 511 /*=0777*/));
};

fs.sendfile = function(outFd, inFd, inOffset, length, callback) {
  binding.sendfile(outFd, inFd, inOffset, length, makeCallback(callback));
};

fs.sendfileSync = function(outFd, inFd, inOffset, length) {
  return binding.sendfile(outFd, inFd, inOffset, length);
};

fs.readdir = function(path, callback) {
  callback = makeCallback(callback);
  if (!nullCheck(path, callback)) return;
  binding.readdir(pathModule._makeLong(path), callback);
};

fs.readdirSync = function(path) {
  nullCheck(path);
  return binding.readdir(pathModule._makeLong(path));
};

fs.fstat = function(fd, callback) {
  binding.fstat(fd, makeCallback(callback));
};

fs.lstat = function(path, callback) {
  callback = makeCallback(callback);
  if (!nullCheck(path, callback)) return;
  binding.lstat(pathModule._makeLong(path), callback);
};

fs.stat = function(path, callback) {
  callback = makeCallback(callback);
  if (!nullCheck(path, callback)) return;
  binding.stat(pathModule._makeLong(path), callback);
};

fs.fstatSync = function(fd) {
  return binding.fstat(fd);
};

fs.lstatSync = function(path) {
  nullCheck(path);
  return binding.lstat(pathModule._makeLong(path));
};

fs.statSync = function(path) {
  nullCheck(path);
  return binding.stat(pathModule._makeLong(path));
};

fs.readlink = function(path, callback) {
  callback = makeCallback(callback);
  if (!nullCheck(path, callback)) return;
  binding.readlink(pathModule._makeLong(path), callback);
};

fs.readlinkSync = function(path) {
  nullCheck(path);
  return binding.readlink(pathModule._makeLong(path));
};

function preprocessSymlinkDestination(path, type) {
  if (!isWindows) {
    // No preprocessing is needed on Unix.
    return path;
  } else if (type === 'junction') {
    // Junctions paths need to be absolute and \\?\-prefixed.
    return pathModule._makeLong(path);
  } else {
    // Windows symlinks don't tolerate forward slashes.
    return ('' + path).replace(/\//g, '\\');
  }
}

fs.symlink = function(destination, path, type_, callback) {
  var type = (typeof type_ === 'string' ? type_ : null);
  var callback = makeCallback(arguments[arguments.length - 1]);

  if (!nullCheck(destination, callback)) return;
  if (!nullCheck(path, callback)) return;

  binding.symlink(preprocessSymlinkDestination(destination, type),
                  pathModule._makeLong(path),
                  type,
                  callback);
};

fs.symlinkSync = function(destination, path, type) {
  type = (typeof type === 'string' ? type : null);

  nullCheck(destination);
  nullCheck(path);

  return binding.symlink(preprocessSymlinkDestination(destination, type),
                         pathModule._makeLong(path),
                         type);
};

fs.link = function(srcpath, dstpath, callback) {
  callback = makeCallback(callback);
  if (!nullCheck(srcpath, callback)) return;
  if (!nullCheck(dstpath, callback)) return;

  binding.link(pathModule._makeLong(srcpath),
               pathModule._makeLong(dstpath),
               callback);
};

fs.linkSync = function(srcpath, dstpath) {
  nullCheck(srcpath);
  nullCheck(dstpath);
  return binding.link(pathModule._makeLong(srcpath),
                      pathModule._makeLong(dstpath));
};

fs.unlink = function(path, callback) {
  callback = makeCallback(callback);
  if (!nullCheck(path, callback)) return;
  binding.unlink(pathModule._makeLong(path), callback);
};

fs.unlinkSync = function(path) {
  nullCheck(path);
  return binding.unlink(pathModule._makeLong(path));
};

fs.fchmod = function(fd, mode, callback) {
  binding.fchmod(fd, modeNum(mode), makeCallback(callback));
};

fs.fchmodSync = function(fd, mode) {
  return binding.fchmod(fd, modeNum(mode));
};

if (constants.hasOwnProperty('O_SYMLINK')) {
  fs.lchmod = function(path, mode, callback) {
    callback = maybeCallback(callback);
    fs.open(path, constants.O_WRONLY | constants.O_SYMLINK, function(err, fd) {
      if (err) {
        callback(err);
        return;
      }
      // prefer to return the chmod error, if one occurs,
      // but still try to close, and report closing errors if they occur.
      fs.fchmod(fd, mode, function(err) {
        fs.close(fd, function(err2) {
          callback(err || err2);
        });
      });
    });
  };

  fs.lchmodSync = function(path, mode) {
    var fd = fs.openSync(path, constants.O_WRONLY | constants.O_SYMLINK);

    // prefer to return the chmod error, if one occurs,
    // but still try to close, and report closing errors if they occur.
    var err, err2;
    try {
      var ret = fs.fchmodSync(fd, mode);
    } catch (er) {
      err = er;
    }
    try {
      fs.closeSync(fd);
    } catch (er) {
      err2 = er;
    }
    if (err || err2) throw (err || err2);
    return ret;
  };
}

fs.chmod = function(path, mode, callback) {
  callback = makeCallback(callback);
  if (!nullCheck(path, callback)) return;
  binding.chmod(pathModule._makeLong(path),
                modeNum(mode),
                callback);
};

fs.chmodSync = function(path, mode) {
  nullCheck(path);
  return binding.chmod(pathModule._makeLong(path), modeNum(mode));
};

if (constants.hasOwnProperty('O_SYMLINK')) {
  fs.lchown = function(path, uid, gid, callback) {
    callback = maybeCallback(callback);
    fs.open(path, constants.O_WRONLY | constants.O_SYMLINK, function(err, fd) {
      if (err) {
        callback(err);
        return;
      }
      fs.fchown(fd, uid, gid, callback);
    });
  };

  fs.lchownSync = function(path, uid, gid) {
    var fd = fs.openSync(path, constants.O_WRONLY | constants.O_SYMLINK);
    return fs.fchownSync(fd, uid, gid);
  };
}

fs.fchown = function(fd, uid, gid, callback) {
  binding.fchown(fd, uid, gid, makeCallback(callback));
};

fs.fchownSync = function(fd, uid, gid) {
  return binding.fchown(fd, uid, gid);
};

fs.chown = function(path, uid, gid, callback) {
  callback = makeCallback(callback);
  if (!nullCheck(path, callback)) return;
  binding.chown(pathModule._makeLong(path), uid, gid, callback);
};

fs.chownSync = function(path, uid, gid) {
  nullCheck(path);
  return binding.chown(pathModule._makeLong(path), uid, gid);
};

// converts Date or number to a fractional UNIX timestamp
function toUnixTimestamp(time) {
  if (typeof time == 'number') {
    return time;
  }
  if (time instanceof Date) {
    // convert to 123.456 UNIX timestamp
    return time.getTime() / 1000;
  }
  throw new Error('Cannot parse time: ' + time);
}

// exported for unit tests, not for public consumption
fs._toUnixTimestamp = toUnixTimestamp;

fs.utimes = function(path, atime, mtime, callback) {
  callback = makeCallback(callback);
  if (!nullCheck(path, callback)) return;
  binding.utimes(pathModule._makeLong(path),
                 toUnixTimestamp(atime),
                 toUnixTimestamp(mtime),
                 callback);
};

fs.utimesSync = function(path, atime, mtime) {
  nullCheck(path);
  atime = toUnixTimestamp(atime);
  mtime = toUnixTimestamp(mtime);
  binding.utimes(pathModule._makeLong(path), atime, mtime);
};

fs.futimes = function(fd, atime, mtime, callback) {
  atime = toUnixTimestamp(atime);
  mtime = toUnixTimestamp(mtime);
  binding.futimes(fd, atime, mtime, makeCallback(callback));
};

fs.futimesSync = function(fd, atime, mtime) {
  atime = toUnixTimestamp(atime);
  mtime = toUnixTimestamp(mtime);
  binding.futimes(fd, atime, mtime);
};

function writeAll(fd, buffer, offset, length, position, callback) {
  callback = maybeCallback(arguments[arguments.length - 1]);

  // write(fd, buffer, offset, length, position, callback)
  fs.write(fd, buffer, offset, length, position, function(writeErr, written) {
    if (writeErr) {
      fs.close(fd, function() {
        if (callback) callback(writeErr);
      });
    } else {
      if (written === length) {
        fs.close(fd, callback);
      } else {
        offset += written;
        length -= written;
        position += written;
        writeAll(fd, buffer, offset, length, position, callback);
      }
    }
  });
}

fs.writeFile = function(path, data, encoding_, callback) {
  var encoding = (typeof(encoding_) == 'string' ? encoding_ : 'utf8');
  assertEncoding(encoding);

  callback = maybeCallback(arguments[arguments.length - 1]);
  fs.open(path, 'w', 438 /*=0666*/, function(openErr, fd) {
    if (openErr) {
      if (callback) callback(openErr);
    } else {
      var buffer = Buffer.isBuffer(data) ? data : new Buffer('' + data,
          encoding);
      writeAll(fd, buffer, 0, buffer.length, 0, callback);
    }
  });
};

fs.writeFileSync = function(path, data, encoding) {
  assertEncoding(encoding);

  var fd = fs.openSync(path, 'w');
  if (!Buffer.isBuffer(data)) {
    data = new Buffer('' + data, encoding || 'utf8');
  }
  var written = 0;
  var length = data.length;
  try {
    while (written < length) {
      written += fs.writeSync(fd, data, written, length - written, written);
    }
  } finally {
    fs.closeSync(fd);
  }
};

fs.appendFile = function(path, data, encoding_, callback) {
  var encoding = (typeof(encoding_) == 'string' ? encoding_ : 'utf8');
  assertEncoding(encoding);

  callback = maybeCallback(arguments[arguments.length - 1]);

  fs.open(path, 'a', 438 /*=0666*/, function(err, fd) {
    if (err) return callback(err);
    var buffer = Buffer.isBuffer(data) ? data : new Buffer('' + data, encoding);
    writeAll(fd, buffer, 0, buffer.length, null, callback);
  });
};

fs.appendFileSync = function(path, data, encoding) {
  assertEncoding(encoding);

  var fd = fs.openSync(path, 'a');
  if (!Buffer.isBuffer(data)) {
    data = new Buffer('' + data, encoding || 'utf8');
  }
  var written = 0;
  var position = null;
  var length = data.length;

  try {
    while (written < length) {
      written += fs.writeSync(fd, data, written, length - written, position);
      position += written; // XXX not safe with multiple concurrent writers?
    }
  } finally {
    fs.closeSync(fd);
  }
};

function errnoException(errorno, syscall) {
  // TODO make this more compatible with ErrnoException from src/node.cc
  // Once all of Node is using this function the ErrnoException from
  // src/node.cc should be removed.
  var e = new Error(syscall + ' ' + errorno);
  e.errno = e.code = errorno;
  e.syscall = syscall;
  return e;
}

function FSWatcher() {
  EventEmitter.call(this);

  var self = this;
  var FSEvent = process.binding('fs_event_wrap').FSEvent;
  this._handle = new FSEvent();
  this._handle.owner = this;

  this._handle.onchange = function(status, event, filename) {
    if (status) {
      self._handle.close();
      self.emit('error', errnoException(errno, 'watch'));
    } else {
      self.emit('change', event, filename);
    }
  };
}
util.inherits(FSWatcher, EventEmitter);

FSWatcher.prototype.start = function(filename, persistent) {
  nullCheck(filename);
  var r = this._handle.start(pathModule._makeLong(filename), persistent);

  if (r) {
    this._handle.close();
    throw errnoException(errno, 'watch');
  }
};

FSWatcher.prototype.close = function() {
  this._handle.close();
};

fs.watch = function(filename) {
  nullCheck(filename);
  var watcher;
  var options;
  var listener;

  if ('object' == typeof arguments[1]) {
    options = arguments[1];
    listener = arguments[2];
  } else {
    options = {};
    listener = arguments[1];
  }

  if (options.persistent === undefined) options.persistent = true;

  watcher = new FSWatcher();
  watcher.start(filename, options.persistent);

  if (listener) {
    watcher.addListener('change', listener);
  }

  return watcher;
};

// Stat Change Watchers

function StatWatcher() {
  EventEmitter.call(this);

  var self = this;
  this._handle = new binding.StatWatcher();

  // uv_fs_poll is a little more powerful than ev_stat but we curb it for
  // the sake of backwards compatibility
  var oldStatus = -1;

  this._handle.onchange = function(current, previous, newStatus) {
    if (oldStatus === -1 &&
        newStatus === -1 &&
        current.nlink === previous.nlink) return;

    oldStatus = newStatus;
    self.emit('change', current, previous);
  };

  this._handle.onstop = function() {
    self.emit('stop');
  };
}
util.inherits(StatWatcher, EventEmitter);

StatWatcher.prototype.start = function(filename, persistent, interval) {
  nullCheck(filename);
  this._handle.start(pathModule._makeLong(filename), persistent, interval);
};

StatWatcher.prototype.stop = function() {
  this._handle.stop();
};

var statWatchers = {};
function inStatWatchers(filename) {
  return Object.prototype.hasOwnProperty.call(statWatchers, filename) &&
      statWatchers[filename];
}

fs.watchFile = function(filename) {
  nullCheck(filename);
  var stat;
  var listener;

  var options = {
    // Poll interval in milliseconds. 5007 is what libev used to use. It's
    // a little on the slow side but let's stick with it for now to keep
    // behavioral changes to a minimum.
    interval: 5007,
    persistent: true
  };

  if ('object' == typeof arguments[1]) {
    options = util._extend(options, arguments[1]);
    listener = arguments[2];
  } else {
    listener = arguments[1];
  }

  if (!listener) {
    throw new Error('watchFile requires a listener function');
  }

  if (inStatWatchers(filename)) {
    stat = statWatchers[filename];
  } else {
    stat = statWatchers[filename] = new StatWatcher();
    stat.start(filename, options.persistent, options.interval);
  }
  stat.addListener('change', listener);
  return stat;
};

fs.unwatchFile = function(filename, listener) {
  nullCheck(filename);
  if (!inStatWatchers(filename)) return;

  var stat = statWatchers[filename];

  if (typeof listener === 'function') {
    stat.removeListener('change', listener);
  } else {
    stat.removeAllListeners('change');
  }

  if (stat.listeners('change').length === 0) {
    stat.stop();
    statWatchers[filename] = undefined;
  }
};

// Realpath
// Not using realpath(2) because it's bad.
// See: http://insanecoding.blogspot.com/2007/11/pathmax-simply-isnt.html

var normalize = pathModule.normalize;

// Regexp that finds the next partion of a (partial) path
// result is [base_with_slash, base], e.g. ['somedir/', 'somedir']
if (isWindows) {
  var nextPartRe = /(.*?)(?:[\/\\]+|$)/g;
} else {
  var nextPartRe = /(.*?)(?:[\/]+|$)/g;
}

// Regex to find the device root, including trailing slash. E.g. 'c:\\'.
if (isWindows) {
  var splitRootRe = /^(?:[a-zA-Z]:|[\\\/]{2}[^\\\/]+[\\\/][^\\\/]+)?[\\\/]*/;
} else {
  var splitRootRe = /^[\/]*/;
}

fs.realpathSync = function realpathSync(p, cache) {
  // make p is absolute
  p = pathModule.resolve(p);

  if (cache && Object.prototype.hasOwnProperty.call(cache, p)) {
    return cache[p];
  }

  var original = p,
      seenLinks = {},
      knownHard = {};

  // current character position in p
  var pos;
  // the partial path so far, including a trailing slash if any
  var current;
  // the partial path without a trailing slash (except when pointing at a root)
  var base;
  // the partial path scanned in the previous round, with slash
  var previous;

  start();

  function start() {
    // Skip over roots
    var m = splitRootRe.exec(p);
    pos = m[0].length;
    current = m[0];
    base = m[0];
    previous = '';

    // On windows, check that the root exists. On unix there is no need.
    if (isWindows && !knownHard[base]) {
      fs.lstatSync(base);
      knownHard[base] = true;
    }
  }

  // walk down the path, swapping out linked pathparts for their real
  // values
  // NB: p.length changes.
  while (pos < p.length) {
    // find the next part
    nextPartRe.lastIndex = pos;
    var result = nextPartRe.exec(p);
    previous = current;
    current += result[0];
    base = previous + result[1];
    pos = nextPartRe.lastIndex;

    // continue if not a symlink
    if (knownHard[base] || (cache && cache[base] === base)) {
      continue;
    }

    var resolvedLink;
    if (cache && Object.prototype.hasOwnProperty.call(cache, base)) {
      // some known symbolic link.  no need to stat again.
      resolvedLink = cache[base];
    } else {
      var stat = fs.lstatSync(base);
      if (!stat.isSymbolicLink()) {
        knownHard[base] = true;
        if (cache) cache[base] = base;
        continue;
      }

      // read the link if it wasn't read before
      // dev/ino always return 0 on windows, so skip the check.
      var linkTarget = null;
      if (!isWindows) {
        var id = stat.dev.toString(32) + ':' + stat.ino.toString(32);
        if (seenLinks.hasOwnProperty(id)) {
          linkTarget = seenLinks[id];
        }
      }
      if (linkTarget === null) {
        fs.statSync(base);
        linkTarget = fs.readlinkSync(base);
      }
      resolvedLink = pathModule.resolve(previous, linkTarget);
      // track this, if given a cache.
      if (cache) cache[base] = resolvedLink;
      if (!isWindows) seenLinks[id] = linkTarget;
    }

    // resolve the link, then start over
    p = pathModule.resolve(resolvedLink, p.slice(pos));
    start();
  }

  if (cache) cache[original] = p;

  return p;
};

fs.realpath = function realpath(p, cache, cb) {
  if (typeof cb !== 'function') {
    cb = maybeCallback(cache);
    cache = null;
  }

  // make p is absolute
  p = pathModule.resolve(p);

  if (cache && Object.prototype.hasOwnProperty.call(cache, p)) {
    return process.nextTick(cb.bind(null, null, cache[p]));
  }

  var original = p,
      seenLinks = {},
      knownHard = {};

  // current character position in p
  var pos;
  // the partial path so far, including a trailing slash if any
  var current;
  // the partial path without a trailing slash (except when pointing at a root)
  var base;
  // the partial path scanned in the previous round, with slash
  var previous;

  start();

  function start() {
    // Skip over roots
    var m = splitRootRe.exec(p);
    pos = m[0].length;
    current = m[0];
    base = m[0];
    previous = '';

    // On windows, check that the root exists. On unix there is no need.
    if (isWindows && !knownHard[base]) {
      fs.lstat(base, function(err) {
        if (err) return cb(err);
        knownHard[base] = true;
        LOOP();
      });
    } else {
      process.nextTick(LOOP);
    }
  }

  // walk down the path, swapping out linked pathparts for their real
  // values
  function LOOP() {
    // stop if scanned past end of path
    if (pos >= p.length) {
      if (cache) cache[original] = p;
      return cb(null, p);
    }

    // find the next part
    nextPartRe.lastIndex = pos;
    var result = nextPartRe.exec(p);
    previous = current;
    current += result[0];
    base = previous + result[1];
    pos = nextPartRe.lastIndex;

    // continue if not a symlink
    if (knownHard[base] || (cache && cache[base] === base)) {
      return process.nextTick(LOOP);
    }

    if (cache && Object.prototype.hasOwnProperty.call(cache, base)) {
      // known symbolic link.  no need to stat again.
      return gotResolvedLink(cache[base]);
    }

    return fs.lstat(base, gotStat);
  }

  function gotStat(err, stat) {
    if (err) return cb(err);

    // if not a symlink, skip to the next path part
    if (!stat.isSymbolicLink()) {
      knownHard[base] = true;
      if (cache) cache[base] = base;
      return process.nextTick(LOOP);
    }

    // stat & read the link if not read before
    // call gotTarget as soon as the link target is known
    // dev/ino always return 0 on windows, so skip the check.
    if (!isWindows) {
      var id = stat.dev.toString(32) + ':' + stat.ino.toString(32);
      if (seenLinks.hasOwnProperty(id)) {
        return gotTarget(null, seenLinks[id], base);
      }
    }
    fs.stat(base, function(err) {
      if (err) return cb(err);

      fs.readlink(base, function(err, target) {
        if (!isWindows) seenLinks[id] = target;
        gotTarget(err, target);
      });
    });
  }

  function gotTarget(err, target, base) {
    if (err) return cb(err);

    var resolvedLink = pathModule.resolve(previous, target);
    if (cache) cache[base] = resolvedLink;
    gotResolvedLink(resolvedLink);
  }

  function gotResolvedLink(resolvedLink) {
    // resolve the link, then start over
    p = pathModule.resolve(resolvedLink, p.slice(pos));
    start();
  }
};

var pool;

function allocNewPool() {
  pool = new Buffer(kPoolSize);
  pool.used = 0;
}

fs.createReadStream = function(path, options) {
  return new ReadStream(path, options);
};

util.inherits(ReadStream, Readable);
fs.ReadStream = ReadStream;

function ReadStream(path, options) {
  if (!(this instanceof ReadStream))
    return new ReadStream(path, options);

  // a little bit bigger buffer and water marks by default
  options = util._extend({
    bufferSize: 64 * 1024,
    lowWaterMark: 16 * 1024,
    highWaterMark: 64 * 1024
  }, options || {});

  Readable.call(this, options);

  this.path = path;
  this.fd = options.hasOwnProperty('fd') ? options.fd : null;
  this.flags = options.hasOwnProperty('flags') ? options.flags : 'r';
  this.mode = options.hasOwnProperty('mode') ? options.mode : 438; /*=0666*/

  this.start = options.hasOwnProperty('start') ? options.start : undefined;
  this.end = options.hasOwnProperty('start') ? options.end : undefined;
  this.pos = undefined;

  if (this.start !== undefined) {
    if ('number' !== typeof this.start) {
      throw TypeError('start must be a Number');
    }
    if (this.end === undefined) {
      this.end = Infinity;
    } else if ('number' !== typeof this.end) {
      throw TypeError('end must be a Number');
    }

    if (this.start > this.end) {
      throw new Error('start must be <= end');
    }

    this.pos = this.start;
  }

  if (typeof this.fd !== 'number')
    this.open();

  this.on('end', function() {
    this.destroy();
  });
}

fs.FileReadStream = fs.ReadStream; // support the legacy name

ReadStream.prototype.open = function() {
  var self = this;
  fs.open(this.path, this.flags, this.mode, function(er, fd) {
    if (er) {
      self.destroy();
      self.emit('error', er);
      return;
    }

    self.fd = fd;
    self.emit('open', fd);
    // start the flow of data.
    self.read();
  });
};

ReadStream.prototype._read = function(n, cb) {
  if (typeof this.fd !== 'number')
    return this.once('open', function() {
      this._read(n, cb);
    });

  if (this.destroyed)
    return;

  if (!pool || pool.length - pool.used < kMinPoolSpace) {
    // discard the old pool. Can't add to the free list because
    // users might have refernces to slices on it.
    pool = null;
    allocNewPool();
  }

  // Grab another reference to the pool in the case that while we're
  // in the thread pool another read() finishes up the pool, and
  // allocates a new one.
  var thisPool = pool;
  var toRead = Math.min(pool.length - pool.used, n);
  var start = pool.used;

  if (this.pos !== undefined)
    toRead = Math.min(this.end - this.pos + 1, toRead);

  // already read everything we were supposed to read!
  // treat as EOF.
  if (toRead <= 0)
    return cb();

  // the actual read.
  var self = this;
  fs.read(this.fd, pool, pool.used, toRead, this.pos, onread);

  // move the pool positions, and internal position for reading.
  if (this.pos !== undefined)
    this.pos += toRead;
  pool.used += toRead;

  function onread(er, bytesRead) {
    if (er) {
      self.destroy();
      return cb(er);
    }

    var b = null;
    if (bytesRead > 0)
      b = thisPool.slice(start, start + bytesRead);

    cb(null, b);
  }
};

ReadStream.prototype.destroy = function() {
  if (this.destroyed)
    return;
  this.destroyed = true;
  if ('number' === typeof this.fd)
    this.close();
};

ReadStream.prototype.close = function(cb) {
  if (cb)
    this.once('close', cb);
  if (this.closed || 'number' !== typeof this.fd) {
    if ('number' !== typeof this.fd)
      this.once('open', close);
    return process.nextTick(this.emit.bind(this, 'close'));
  }
  this.closed = true;
  var self = this;
  close();

  function close() {
    fs.close(self.fd, function(er) {
      if (er)
        self.emit('error', er);
      else
        self.emit('close');
    });
  }
};

fs.createWriteStream = function(path, options) {
  return new WriteStream(path, options);
};

util.inherits(WriteStream, Writable);
fs.WriteStream = WriteStream;
function WriteStream(path, options) {
  if (!(this instanceof WriteStream))
    return new WriteStream(path, options);

  // a little bit bigger buffer and water marks by default
  options = util._extend({
    bufferSize: 64 * 1024,
    lowWaterMark: 16 * 1024,
    highWaterMark: 64 * 1024
  }, options || {});

  Writable.call(this, options);

  this.path = path;
  this.fd = null;

  this.fd = options.hasOwnProperty('fd') ? options.fd : null;
  this.flags = options.hasOwnProperty('flags') ? options.flags : 'w';
  this.mode = options.hasOwnProperty('mode') ? options.mode : 438; /*=0666*/

  this.start = options.hasOwnProperty('start') ? options.start : undefined;
  this.pos = undefined;
  this.bytesWritten = 0;

  if (this.start !== undefined) {
    if ('number' !== typeof this.start) {
      throw TypeError('start must be a Number');
    }
    if (this.start < 0) {
      throw new Error('start must be >= zero');
    }

    this.pos = this.start;
  }

  if ('number' !== typeof this.fd)
    this.open();

  // dispose on finish.
  this.once('finish', this.close);
}

fs.FileWriteStream = fs.WriteStream; // support the legacy name

WriteStream.prototype.open = function() {
  fs.open(this.path, this.flags, this.mode, function(er, fd) {
    if (er) {
      this.destroy();
      this.emit('error', er);
      return;
    }

    this.fd = fd;
    this.emit('open', fd);
  }.bind(this));
};

WriteStream.prototype._write = function(data, cb) {
  if (!Buffer.isBuffer(data))
    return this.emit('error', new Error('Invalid data'));

  if (typeof this.fd !== 'number')
    return this.once('open', this._write.bind(this, data, cb));

  fs.write(this.fd, data, 0, data.length, this.pos, function(er, bytes) {
    if (er) {
      this.destroy();
      return cb(er);
    }
    this.bytesWritten += bytes;
    cb();
  }.bind(this));

  if (this.pos !== undefined)
    this.pos += data.length;
};

WriteStream.prototype.destroy = ReadStream.prototype.destroy;
WriteStream.prototype.close = ReadStream.prototype.close;

// There is no shutdown() for files.
WriteStream.prototype.destroySoon = WriteStream.prototype.end;

// SyncWriteStream is internal. DO NOT USE.
// Temporary hack for process.stdout and process.stderr when piped to files.
function SyncWriteStream(fd) {
  Stream.call(this);

  this.fd = fd;
  this.writable = true;
  this.readable = false;
}

util.inherits(SyncWriteStream, Stream);

// Export
fs.SyncWriteStream = SyncWriteStream;

SyncWriteStream.prototype.write = function(data, arg1, arg2) {
  var encoding, cb;

  // parse arguments
  if (arg1) {
    if (typeof arg1 === 'string') {
      encoding = arg1;
      cb = arg2;
    } else if (typeof arg1 === 'function') {
      cb = arg1;
    } else {
      throw new Error('bad arg');
    }
  }
  assertEncoding(encoding);

  // Change strings to buffers. SLOW
  if (typeof data == 'string') {
    data = new Buffer(data, encoding);
  }

  fs.writeSync(this.fd, data, 0, data.length);

  if (cb) {
    process.nextTick(cb);
  }

  return true;
};

SyncWriteStream.prototype.end = function(data, arg1, arg2) {
  if (data) {
    this.write(data, arg1, arg2);
  }
  this.destroy();
};

SyncWriteStream.prototype.destroy = function() {
  fs.closeSync(this.fd);
  this.fd = null;
  this.emit('close');
  return true;
};

SyncWriteStream.prototype.destroySoon = SyncWriteStream.prototype.destroy;


FileTreeView.render(fileTreeViewContainer, model._viewModel, projectRoot, actionCreator, forceRender, brackets.platform);

<!DOCTYPE html>

	<meta charset="utf-8">
	<title>jQuery UI Widget Test Suite</title>

	<link rel="stylesheet" href="../../../external/qunit.css">

jQuery UI Widget Test Suite

...


* @param {int} scrollWidth Width of the tree container

/*
 * Copyright (c) 2014 Adobe Systems Incorporated. All rights reserved.
 *
 * 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.
 *
 */

/* unittests: ProjectModel */
/*global define, brackets, $ */

/**
 * Provides the data source for a project and manages the view model for the FileTreeView.
 */
define(function (require, exports, module) {
    "use strict";

    var InMemoryFile        = require("document/InMemoryFile"),
        FileUtils           = require("file/FileUtils"),
        _                   = require("thirdparty/lodash"),
        FileSystem          = require("filesystem/FileSystem"),
        FileSystemError     = require("filesystem/FileSystemError"),
        FileTreeViewModel   = require("project/FileTreeViewModel"),
        Async               = require("utils/Async");

    // Constants
    var EVENT_CHANGE            = "change",
        EVENT_SHOULD_SELECT     = "select",
        EVENT_SHOULD_FOCUS      = "focus",
        ERROR_CREATION          = "creationError",
        ERROR_INVALID_FILENAME  = "invalidFilename";

    /**
     * @private
     * File and folder names which are not displayed or searched
     * TODO: We should add the rest of the file names that TAR excludes:
     *    http://www.gnu.org/software/tar/manual/html_section/exclude.html
     * TODO: This should be user configurable
     *    https://github.com/adobe/brackets/issues/6781
     * @type {RegExp}
     */
    var _exclusionListRegEx = /\.pyc$|^\.git$|^\.gitmodules$|^\.svn$|^\.DS_Store$|^Thumbs\.db$|^\.hg$|^CVS$|^\.hgtags$|^\.idea$|^\.c9revisions$|^\.SyncArchive$|^\.SyncID$|^\.SyncIgnore$|\~$/;

    /**
     * @private
     * A string containing all invalid characters for a specific platform.
     * This will be used to construct a regular expression for checking invalid filenames.
     * When a filename with one of these invalid characters are detected, then it is
     * also used to substitute the place holder of the error message.
     */
    var _invalidChars;

    /**
     * @private
     * RegEx to validate if a filename is not allowed even if the system allows it.
     * This is done to prevent cross-platform issues.
     */

    var _illegalFilenamesRegEx = /^(\.+|com[1-9]|lpt[1-9]|nul|con|prn|aux|)$|\.+$/i;

    /**
     * Returns true if this matches valid filename specifications.
     *
     * TODO: This likely belongs in FileUtils.
     *
     * @param {string} filename to check
     * @param {string} invalidChars List of characters that are disallowed
     * @return {boolean} true if the filename is valid
     */
    function isValidFilename(filename, invalidChars) {
        // Validate file name
        // Checks for valid Windows filenames:
        // See http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
        return !((filename.search(new RegExp("[" + invalidChars + "]+")) !== -1) ||
                 filename.match(_illegalFilenamesRegEx));
    }

    /**
     * @private
     * See shouldShow
     */
    function _shouldShowName(name) {
        return !name.match(_exclusionListRegEx);
    }

    /**
     * Returns false for files and directories that are not commonly useful to display.
     *
     * @param {!FileSystemEntry} entry File or directory to filter
     * @return {boolean} true if the file should be displayed
     */
    function shouldShow(entry) {
        return _shouldShowName(entry.name);
    }

    // Constants used by the ProjectModel

    var FILE_RENAMING     = 0,
        FILE_CREATING     = 1,
        RENAME_CANCELLED  = 2;

    /**
     * @private
     *
     * Determines if a path string is pointing to a directory (does it have a trailing slash?)
     *
     * @param {string} path Path to test.
     */
    function _pathIsFile(path) {
        return _.last(path) !== "/";
    }

    /**
     * @private
     *
     * Gets the FileSystem object (either a File or Directory) based on the path provided.
     *
     * @param {string} path Path to retrieve
     */
    function _getFSObject(path) {
        if (!path) {
            return path;
        } else if (_pathIsFile(path)) {
            return FileSystem.getFileForPath(path);
        }
        return FileSystem.getDirectoryForPath(path);
    }

    /**
     * @private
     *
     * Given what is possible a FileSystem object, return its path (if a string path is passed in,
     * it will be returned as-is).
     *
     * @param {FileSystemEntry} fsobj Object from which the path should be extracted
     */
    function _getPathFromFSObject(fsobj) {
        if (fsobj && fsobj.fullPath) {
            return fsobj.fullPath;
        }
        return fsobj;
    }

    /**
     * Creates a new file or folder at the given path. The returned promise is rejected if the filename
     * is invalid, the new path already exists or some other filesystem error comes up.
     *
     * @param {string} path path to create
     * @param {boolean} isFolder true if the new entry is a folder
     * @return {$.Promise} resolved when the file or directory has been created.
     */
    function doCreate(path, isFolder) {
        var d = new $.Deferred();

        var name = FileUtils.getBaseName(path);
        if (!isValidFilename(name, _invalidChars)) {
            return d.reject(ERROR_INVALID_FILENAME).promise();
        }

        FileSystem.resolve(path, function (err) {
            if (!err) {
                // Item already exists, fail with error
                d.reject(FileSystemError.ALREADY_EXISTS);
            } else {
                if (isFolder) {
                    var directory = FileSystem.getDirectoryForPath(path);

                    directory.create(function (err) {
                        if (err) {
                            d.reject(err);
                        } else {
                            d.resolve(directory);
                        }
                    });
                } else {
                    // Create an empty file
                    var file = FileSystem.getFileForPath(path);

                    FileUtils.writeText(file, "").then(function () {
                        d.resolve(file);
                    }, d.reject);
                }
            }
        });

        return d.promise();
    }

    /**
     * @constructor
     *
     * The ProjectModel provides methods for accessing information about the current open project.
     * It also manages the view model to display a FileTreeView of the project.
     */
    function ProjectModel(initial) {
        initial = initial || {};
        if (initial.projectRoot) {
            this.projectRoot = initial.projectRoot;
        }

        if (initial.focused !== undefined) {
            this._focused = initial.focused;
        }
        this._viewModel = new FileTreeViewModel.FileTreeViewModel();
        this._viewModel.on(FileTreeViewModel.EVENT_CHANGE, function () {
            $(this).trigger(EVENT_CHANGE);
        }.bind(this));
        this._selections = {};
    }

    /**
     * @type {Directory}
     *
     * The root Directory object for the project.
     */
    ProjectModel.prototype.projectRoot = null;

    /**
     * @private
     * @type {FileTreeViewModel}
     *
     * The view model for this project.
     */
    ProjectModel.prototype._viewModel = null;

    /**
     * @private
     * @type {string}
     *
     * Encoded URL
     * @see getBaseUrl(), setBaseUrl()
     */
    ProjectModel.prototype._projectBaseUrl = "";

    /**
     * @private
     * @type {{selected: ?string, context: ?string, previousContext: ?string, rename: ?Object}}
     *
     * Keeps track of selected files, context, previous context and files
     * that are being renamed or created.
     */
    ProjectModel.prototype._selections = null;

    /**
     * @private
     * @type {boolean}
     *
     * Flag to store whether the file tree has focus.
     */
    ProjectModel.prototype._focused = true;

    /**
     * @private
     * @type {string}
     *
     * Current file path being viewed.
     */
    ProjectModel.prototype._currentPath = null;

    /**
     * @private
     * @type {?$.Promise.<Array<File>>}
     *
     * A promise that is resolved with an array of all project files. Used by
     * ProjectManager.getAllFiles().
     */
    ProjectModel.prototype._allFilesCachePromise = null;

    /**
     * Sets whether the file tree is focused or not.
     *
     * @param {boolean} focused True if the file tree has the focus.
     */
    ProjectModel.prototype.setFocused = function (focused) {
        this._focused = focused;
        if (!focused) {
            this.setSelected(null);
        }
    };

    /**
     * Sets the width of the selection bar.
     *
     * @param {int} width New width
     */
    ProjectModel.prototype.setSelectionWidth = function (width) {
        this._viewModel.setSelectionWidth(width);
    };

    /**
     * Tracks the scroller position.
     *
     * @param {int} scrollTop Top of scroll position
     * @param {int} scrollLeft Left of scroll position
     * @param {int} offsetTop Top of scroller element
     */
    ProjectModel.prototype.setScrollerInfo = function (scrollTop, scrollLeft, offsetTop) {
        this._viewModel.setSelectionScrollerInfo(scrollTop, scrollLeft, offsetTop);
    };

    /**
     * Returns the encoded Base URL of the currently loaded project, or empty string if no project
     * is open (during startup, or running outside of app shell).
     * @return {String}
     */
    ProjectModel.prototype.getBaseUrl = function getBaseUrl() {
        return this._projectBaseUrl;
    };

    /**
     * Sets the encoded Base URL of the currently loaded project.
     * @param {String}
     */
    ProjectModel.prototype.setBaseUrl = function setBaseUrl(projectBaseUrl) {
        // Ensure trailing slash to be consistent with projectRoot.fullPath
        // so they're interchangable (i.e. easy to convert back and forth)
        if (projectBaseUrl.length > 0 && projectBaseUrl[projectBaseUrl.length - 1] !== "/") {
            projectBaseUrl += "/";
        }

        this._projectBaseUrl = projectBaseUrl;
        return projectBaseUrl;
    };

    /**
     * Returns true if absPath lies within the project, false otherwise.
     * Does not support paths containing ".."
     *
     * @param {string|FileSystemEntry} absPathOrEntry
     * @return {boolean}
     */
    ProjectModel.prototype.isWithinProject = function isWithinProject(absPathOrEntry) {
        var absPath = absPathOrEntry.fullPath || absPathOrEntry;
        return (this.projectRoot && absPath.indexOf(this.projectRoot.fullPath) === 0);
    };

    /**
     * If absPath lies within the project, returns a project-relative path. Else returns absPath
     * unmodified.
     * Does not support paths containing ".."
     *
     * @param {!string} absPath
     * @return {!string}
     */
    ProjectModel.prototype.makeProjectRelativeIfPossible = function makeProjectRelativeIfPossible(absPath) {
        if (absPath && this.isWithinProject(absPath)) {
            return absPath.slice(this.projectRoot.fullPath.length);
        }
        return absPath;
    };

    /**
     * @private
     *
     * Returns a promise that resolves with a cached copy of all project files.
     * Used by ProjectManager.getAllFiles(). Ensures that at most one un-cached
     * directory traversal is active at a time, which is useful at project load
     * time when watchers (and hence filesystem-level caching) has not finished
     * starting up. The cache is cleared on every filesystem change event, and
     * also on project load and unload.
     *
     * @return {$.Promise.<Array.<File>>}
     */
    ProjectModel.prototype._getAllFilesCache = function _getAllFilesCache() {
        if (!this._allFilesCachePromise) {
            var deferred = new $.Deferred(),
                allFiles = [],
                allFilesVisitor = function (entry) {
                    if (shouldShow(entry)) {
                        if (entry.isFile) {
                            allFiles.push(entry);
                        }
                        return true;
                    }
                    return false;
                };

            this._allFilesCachePromise = deferred.promise();

            this.projectRoot.visit(allFilesVisitor, function (err) {
                if (err) {
                    deferred.reject(err);
                } else {
                    deferred.resolve(allFiles);
                }
            }.bind(this));
        }

        return this._allFilesCachePromise;
    };

    /**
     * Returns an Array of all files for this project, optionally including
     * files additional files provided. Files are filtered out by shouldShow().
     *
     * @param {function (File, number):boolean=} filter Optional function to filter
     *          the file list (does not filter directory traversal). API matches Array.filter().
     * @param {Array.<File>=} additionalFiles Additional files to include (for example, the WorkingSet)
     *          Only adds files that are *not* under the project root or untitled documents.
     *
     * @return {$.Promise} Promise that is resolved with an Array of File objects.
     */
    ProjectModel.prototype.getAllFiles = function getAllFiles(filter, additionalFiles) {
        // The filter and includeWorkingSet params are both optional.
        // Handle the case where filter is omitted but includeWorkingSet is
        // specified.
        if (additionalFiles === undefined && typeof (filter) !== "function") {
            additionalFiles = filter;
            filter = null;
        }

        var filteredFilesDeferred = new $.Deferred();

        // First gather all files in project proper
        // Note that with proper promises we may be able to fix this so that we're not doing this
        // anti-pattern of creating a separate deferred rather than just chaining off of the promise
        // from _getAllFilesCache
        this._getAllFilesCache().done(function (result) {
            // Add working set entries, if requested
            if (additionalFiles) {
                additionalFiles.forEach(function (file) {
                    if (result.indexOf(file) === -1 && !(file instanceof InMemoryFile)) {
                        result.push(file);
                    }
                });
            }

            // Filter list, if requested
            if (filter) {
                result = result.filter(filter);
            }

            // If a done handler attached to the returned filtered files promise
            // throws an exception that isn't handled here then it will leave
            // _allFilesCachePromise in an inconsistent state such that no
            // additional done handlers will ever be called!
            try {
                filteredFilesDeferred.resolve(result);
            } catch (e) {
                console.warn("Unhandled exception in getAllFiles handler: ", e);
            }
        }).fail(function (err) {
            try {
                filteredFilesDeferred.reject(err);
            } catch (e) {
                console.warn("Unhandled exception in getAllFiles handler: ", e);
            }
        });

        return filteredFilesDeferred.promise();
    };

    /**
     * @private
     *
     * Resets the all files cache.
     */
    ProjectModel.prototype._resetCache = function _resetCache() {
        this._allFilesCachePromise = null;
    };

    /**
     * Adds an event listener for this ProjectModel. See jQuery's documentation for .on.
     *
     * Available events:
     *
     * * EVENT_CHANGE (`change`) - Fired when there's a change that should refresh the UI
     * * EVENT_SHOULD_SELECT (`select`) - Specifies that a selection has been made in the file tree and that the file tree should be selected
     * * ERROR_CREATION (`creationError`) - Triggered when there is a problem creating a file.
     */
    ProjectModel.prototype.on = function (event, handler) {
        $(this).on(event, handler);
    };

    /**
     * Removes an event listener for this ProjectModel. See jQuery's documentation for .off.
     */
    ProjectModel.prototype.off = function (event, handler) {
        $(this).off(event, handler);
    };

    /**
     * Sets the project root (effectively resetting this ProjectModel).
     *
     * @param {Directory} projectRoot new project root
     * @return {$.Promise} resolved when the project root has been updated
     */
    ProjectModel.prototype.setProjectRoot = function (projectRoot) {
        this.projectRoot = projectRoot;
        this._resetCache();
        this._viewModel._rootChanged();

        var d = new $.Deferred(),
            self = this;

        projectRoot.getContents(function (err, contents) {
            if (err) {
                d.reject(err);
            } else {
                self._viewModel.setDirectoryContents("", contents);
                d.resolve();
            }
        });
        return d.promise();
    };

    /**
     * @private
     *
     * Gets the contents of a directory at the given path.
     *
     * @param {string} path path to retrieve
     * @return {$.Promise} Resolved with the directory contents.
     */
    ProjectModel.prototype._getDirectoryContents = function (path) {
        var d = new $.Deferred();
        FileSystem.getDirectoryForPath(path).getContents(function (err, contents) {
            if (err) {
                d.reject(err);
            } else {
                d.resolve(contents);
            }
        });
        return d.promise();
    };

    /**
     * Opens or closes the given directory in the file tree.
     *
     * @param {string} path Path to open
     * @param {boolean} open `true` to open the path
     * @return {$.Promise} resolved when the path has been opened.
     */
    ProjectModel.prototype.setDirectoryOpen = function (path, open) {
        var projectRelative = this.makeProjectRelativeIfPossible(path),
            needsLoading    = !this._viewModel.isPathLoaded(projectRelative),
            d               = new $.Deferred(),
            self            = this;

        function onSuccess(contents) {
            // Update the view model
            if (contents) {
                self._viewModel.setDirectoryContents(projectRelative, contents);
            }

            if (open) {
                self._viewModel.openPath(projectRelative);
                if (self._focused) {
                    var currentPathInProject = self.makeProjectRelativeIfPossible(self._currentPath);
                    if (self._viewModel.isFilePathVisible(currentPathInProject)) {
                        self.setSelected(self._currentPath, true);
                    } else {
                        self.setSelected(null);
                    }
                }
            } else {
                self._viewModel.setDirectoryOpen(projectRelative, false);
                var selected = self._selections.selected;
                if (selected) {
                    var relativeSelected = self.makeProjectRelativeIfPossible(selected);
                    if (!self._viewModel.isFilePathVisible(relativeSelected)) {
                        self.setSelected(null);
                    }
                }
            }

            d.resolve();
        }

        // If the view model doesn't have the data it needs, we load it now, otherwise we can just
        // manage the selection and resovle the promise.
        if (open && needsLoading) {
            var parentDirectory = FileUtils.getDirectoryPath(FileUtils.stripTrailingSlash(path));
            this.setDirectoryOpen(parentDirectory, true).then(function () {
                self._getDirectoryContents(path).then(onSuccess).fail(function (err) {
                    d.reject(err);
                });
            }, function (err) {
                d.reject(err);
            });
        } else {
            onSuccess();
        }

        return d.promise();
    };

    /**
     * Shows the given path in the tree and selects it if it's a file. Any intermediate directories
     * will be opened and a promise is returned to show when the entire operation is complete.
     *
     * @param {string|File|Directory} path full path to the file or directory
     * @return {$.Promise} promise resolved when the path is shown
     */
    ProjectModel.prototype.showInTree = function (path) {
        var d = new $.Deferred();
        path = _getPathFromFSObject(path);

        var projectRelative = this.makeProjectRelativeIfPossible(path);

        // Not in project?
        if (projectRelative[0] === "/") {
            d.resolve();
        } else {
            var parentDirectory = FileUtils.getDirectoryPath(path),
                self = this;
            this.setDirectoryOpen(parentDirectory, true).then(function () {
                if (_pathIsFile(path)) {
                    self.setSelected(path);
                }
                d.resolve();
            }, function (err) {
                d.reject(err);
            });
        }
        return d.promise();
    };

    /**
     * Selects the given path in the file tree and opens the file (unless doNotOpen is specified).
     * Directories will not be selected.
     *
     * When the selection changes, any rename operation that is currently underway will be completed.
     *
     * @param {string} path full path to the file being selected
     * @param {boolean} doNotOpen `true` if the file should not be opened.
     */
    ProjectModel.prototype.setSelected = function (path, doNotOpen) {
        path = _getPathFromFSObject(path);

        // Directories are not selectable
        if (!_pathIsFile(path)) {
            return;
        }

        var oldProjectPath = this.makeProjectRelativeIfPossible(this._selections.selected),
            pathInProject = this.makeProjectRelativeIfPossible(path);

        if (path && !this._viewModel.isFilePathVisible(pathInProject)) {
            path = null;
            pathInProject = null;
        }

        this.performRename();

        this._viewModel.moveMarker("selected", oldProjectPath, pathInProject);
        if (this._selections.context) {
            this._viewModel.moveMarker("context", this.makeProjectRelativeIfPossible(this._selections.context), null);
            delete this._selections.context;
        }

        var previousSelection = this._selections.selected;
        this._selections.selected = path;

        if (path) {
            if (!doNotOpen) {
                $(this).trigger(EVENT_SHOULD_SELECT, {
                    path: path,
                    previousPath: previousSelection,
                    hadFocus: this._focused
                });
            }

            $(this).trigger(EVENT_SHOULD_FOCUS);
        }
    };

    /**
     * Gets the currently selected file or directory.
     *
     * @return {FileSystemEntry} the filesystem object for the currently selected file
     */
    ProjectModel.prototype.getSelected = function () {
        return _getFSObject(this._selections.selected);
    };

    /**
     * Keeps track of which file is currently being edited.
     *
     * @param {File|string} curFile Currently edited file.
     */
    ProjectModel.prototype.setCurrentFile = function (curFile) {
        this._currentPath = _getPathFromFSObject(curFile);
    };

    /**
     * Adds the file at the given path to the Working Set and selects it there.
     *
     * @param {string} path full path of file to open in Working Set
     */
    ProjectModel.prototype.selectInWorkingSet = function (path) {
        this.performRename();
        $(this).trigger(EVENT_SHOULD_SELECT, {
            path: path,
            add: true
        });
    };

    /**
     * Sets the context (for context menu operations) to the given path. This is independent from the
     * open/selected file.
     *
     * @param {string} path full path of file or directory to which the context should be setBaseUrl
     * @param {boolean} _doNotRename True if this context change should not cause a rename operation to finish. This is a special case that goes with context menu handling.
     * @param {boolean} _saveContext True if the current context should be saved (see comment below)
     */
    ProjectModel.prototype.setContext = function (path, _doNotRename, _saveContext) {
        // This bit is not ideal: when the user right-clicks on an item in the file tree
        // and there is already a context menu up, the FileTreeView sends a signal to set the
        // context to the new element but the PopupManager follows that with a message that it's
        // closing the context menu (because it closes the previous one and then opens the new
        // one.) This timing means that we need to provide some special case handling here.
        if (_saveContext) {
            if (!path) {
                this._selections.previousContext = this._selections.context;
            } else {
                this._selections.previousContext = path;
            }
        } else {
            delete this._selections.previousContext;
        }

        path = _getPathFromFSObject(path);

        if (!_doNotRename) {
            this.performRename();
        }
        var currentContext = this._selections.context;
        this._selections.context = path;
        this._viewModel.moveMarker("context", this.makeProjectRelativeIfPossible(currentContext),
                                   this.makeProjectRelativeIfPossible(path));
    };

    /**
     * Restores the context to the last non-null context. This is specifically here to handle
     * the sequence of messages that we get from the project context menu.
     */
    ProjectModel.prototype.restoreContext = function () {
        if (this._selections.previousContext) {
            this.setContext(this._selections.previousContext);
        }
    };

    /**
     * Gets the currently selected context.
     *
     * @return {FileSystemEntry} filesystem object for the context file or directory
     */
    ProjectModel.prototype.getContext = function () {
        return _getFSObject(this._selections.context);
    };

    /**
     * Starts a rename operation for the file or directory at the given path. If the path is
     * not provided, the current context is used.
     *
     * If a rename operation is underway, it will be completed automatically.
     *
     * The Promise returned is resolved with an object with a `newPath` property with the renamed path. If the user cancels the operation, the promise is resolved with the value RENAME_CANCELLED.
     *
     * @param {string=} path optional path to start renaming
     * @return {$.Promise} resolved when the operation is complete.
     */
    ProjectModel.prototype.startRename = function (path) {
        path = _getPathFromFSObject(path);
        if (!path) {
            path = this._selections.context;
            if (!path) {
                return new $.Deferred().resolve().promise();
            }
        }

        if (this._selections.rename && this._selections.rename.path === path) {
            return;
        }

        if (path !== this._selections.context) {
            this.setContext(path);
        } else {
            this.performRename();
        }

        this._viewModel.moveMarker("rename", null,
                                   this.makeProjectRelativeIfPossible(path));
        var d = new $.Deferred();
        this._selections.rename = {
            deferred: d,
            type: FILE_RENAMING,
            path: path,
            newName: FileUtils.getBaseName(path)
        };
        return d.promise();
    };

    /**
     * Sets the new value for the rename operation that is in progress (started previously with a call
     * to `startRename`).
     *
     * @param {string} name new name for the file or directory being renamed
     */
    ProjectModel.prototype.setRenameValue = function (name) {
        if (!this._selections.rename) {
            return;
        }
        this._selections.rename.newName = name;
    };

    /**
     * Cancels the rename operation that is in progress. This resolves the original promise with
     * a RENAME_CANCELLED value.
     */
    ProjectModel.prototype.cancelRename = function () {
        var renameInfo = this._selections.rename;
        if (!renameInfo) {
            return;
        }

        // File creation is a special case.
        if (renameInfo.type === FILE_CREATING) {
            this._cancelCreating();
            return;
        }

        this._viewModel.moveMarker("rename", this.makeProjectRelativeIfPossible(renameInfo.path), null);
        renameInfo.deferred.resolve(RENAME_CANCELLED);
        delete this._selections.rename;
        this.setContext(null);
    };

    /**
     * Rename a file/folder. This will update the project tree data structures
     * and send notifications about the rename.
     *
     * @param {string} oldName Old item name
     * @param {string} newName New item name
     * @param {boolean} isFolder True if item is a folder; False if it is a file.
     * @return {$.Promise} A promise object that will be resolved or rejected when
     *   the rename is finished.
     */
    function _renameItem(oldName, newName, isFolder) {
        var result = new $.Deferred();

        if (oldName === newName) {
            result.resolve();
        } else if (!isValidFilename(FileUtils.getBaseName(newName), _invalidChars)) {
            result.reject(ERROR_INVALID_FILENAME);
        } else {
            var entry = isFolder ? FileSystem.getDirectoryForPath(oldName) : FileSystem.getFileForPath(oldName);
            entry.rename(newName, function (err) {
                if (err) {
                    result.reject(err);
                } else {
                    result.resolve();
                }
            });
        }

        return result.promise();
    }

    /**
     * @private
     *
     * Renames the item at the old path to the new name provided.
     *
     * @param {string} oldPath full path to the current location of file or directory (should include trailing slash for directory)
     * @param {string} newName new name for the file or directory
     */
    ProjectModel.prototype._renameItem = function (oldPath, newName) {
        return _renameItem(oldPath, newName, !_pathIsFile(oldPath));
    };

    /**
     * Completes the rename operation that is in progress.
     */
    ProjectModel.prototype.performRename = function () {
        var renameInfo = this._selections.rename;
        if (!renameInfo) {
            return;
        }
        var oldPath         = renameInfo.path,
            isFolder        = renameInfo.isFolder || !_pathIsFile(oldPath),
            oldProjectPath  = this.makeProjectRelativeIfPossible(oldPath),

            // To get the parent directory, we need to strip off the trailing slash on a directory name
            parentDirectory = FileUtils.getDirectoryPath(isFolder ? FileUtils.stripTrailingSlash(oldPath) : oldPath),
            oldName         = FileUtils.getBaseName(oldPath),
            newName         = renameInfo.newName,
            newPath         = parentDirectory + newName,
            viewModel       = this._viewModel,
            self            = this;

        if (renameInfo.type !== FILE_CREATING && oldName === newName) {
            this.cancelRename();
            return;
        }

        if (isFolder) {
            newPath += "/";
        }

        delete this._selections.rename;
        delete this._selections.context;
        if (this._selections.selected === oldPath) {
            this._selections.selected = newPath;
        }

        viewModel.moveMarker("rename", oldProjectPath, null);
        viewModel.moveMarker("context", oldProjectPath, null);
        viewModel.moveMarker("creating", oldProjectPath, null);

        if (renameInfo.type === FILE_CREATING) {
            this.createAtPath(newPath).done(function (entry) {
                viewModel.renameItem(oldProjectPath, newName);

                renameInfo.deferred.resolve(entry);
            }).fail(function (error) {
                self._viewModel.deleteAtPath(self.makeProjectRelativeIfPossible(renameInfo.path));
                renameInfo.deferred.reject(error);
            });
        } else {
            this._renameItem(oldPath, newPath).then(function () {
                viewModel.renameItem(oldProjectPath, newName);
                renameInfo.deferred.resolve({
                    newPath: newPath
                });
            }).fail(function (errorType) {
                var errorInfo = {
                    type: errorType,
                    isFolder: isFolder,
                    fullPath: oldPath
                };
                renameInfo.deferred.reject(errorInfo);
            });
        }
    };

    /**
     * Creates a file or folder at the given path. Folder paths should have a trailing slash.
     *
     * If an error comes up during creation, the ERROR_CREATION event is triggered.
     *
     * @param {string} path full path to file or folder to create
     * @return {$.Promise} resolved when creation is complete
     */
    ProjectModel.prototype.createAtPath = function (path) {
        var isFolder  = !_pathIsFile(path),
            name      = FileUtils.getBaseName(path),
            self      = this;

        return doCreate(path, isFolder).done(function (entry) {
            if (!isFolder) {
                self.selectInWorkingSet(entry.fullPath);
            }
        }).fail(function (error) {
            $(self).trigger(ERROR_CREATION, {
                type: error,
                name: name,
                isFolder: isFolder
            });
        });
    };

    /**
     * Starts creating a file or folder with the given name in the given directory.
     *
     * The Promise returned is resolved with an object with a `newPath` property with the renamed path. If the user cancels the operation, the promise is resolved with the value RENAME_CANCELLED.
     *
     * @param {string} basedir directory that should contain the new entry
     * @param {string} newName initial name for the new entry (the user can rename it)
     * @param {boolean} isFolder `true` if the entry being created is a folder
     * @return {$.Promise} resolved when the user is done creating the entry.
     */
    ProjectModel.prototype.startCreating = function (basedir, newName, isFolder) {
        this.performRename();
        var d = new $.Deferred(),
            self = this;

        this.setDirectoryOpen(basedir, true).then(function () {
            self._viewModel.createPlaceholder(self.makeProjectRelativeIfPossible(basedir), newName, isFolder);
            var promise = self.startRename(basedir + newName);
            self._selections.rename.type = FILE_CREATING;
            if (isFolder) {
                self._selections.rename.isFolder = isFolder;
            }
            promise.then(d.resolve).fail(d.reject);
        }).fail(function (err) {
            d.reject(err);
        });
        return d.promise();
    };

    /**
     * Cancels the creation process that is underway. The original promise returned will be resolved with the
     * RENAME_CANCELLED value. The temporary entry added to the file tree will be deleted.
     */
    ProjectModel.prototype._cancelCreating = function () {
        var renameInfo = this._selections.rename;
        if (!renameInfo || renameInfo.type !== FILE_CREATING) {
            return;
        }
        this._viewModel.deleteAtPath(this.makeProjectRelativeIfPossible(renameInfo.path));
        renameInfo.deferred.resolve(RENAME_CANCELLED);
        delete this._selections.rename;
        this.setContext(null);
    };

    /**
     * Sets the `sortDirectoriesFirst` option for the file tree view.
     *
     * @param {boolean} True if directories should appear first
     */
    ProjectModel.prototype.setSortDirectoriesFirst = function (sortDirectoriesFirst) {
        this._viewModel.setSortDirectoriesFirst(sortDirectoriesFirst);
    };

    /**
     * Gets an array of arrays where each entry of the top-level array has an array
     * of paths that are at the same depth in the tree. All of the paths are full paths.
     *
     * @return {Array.<Array.<string>>} Array of array of full paths, organized by depth in the tree.
     */
    ProjectModel.prototype.getOpenNodes = function () {
        return this._viewModel.getOpenNodes(this.projectRoot.fullPath);
    };

    /**
     * Reopens a set of nodes in the tree by full path.
     * @param {Array.<Array.<string>>} nodesByDepth An array of arrays of node ids to reopen. The ids within
     *     each sub-array are reopened in parallel, and the sub-arrays are reopened in order, so they should
     *     be sorted by depth within the tree.
     * @return {$.Deferred} A promise that will be resolved when all nodes have been fully
     *     reopened.
     */
    ProjectModel.prototype.reopenNodes = function (nodesByDepth) {
        var deferred = new $.Deferred();

        if (!nodesByDepth || nodesByDepth.length === 0) {
            // All paths are opened and fully rendered.
            return deferred.resolve().promise();
        } else {
            var self = this;
            return Async.doSequentially(nodesByDepth, function (toOpenPaths) {
                return Async.doInParallel(
                    toOpenPaths,
                    function (path) {
                        return self._getDirectoryContents(path).then(function (contents) {
                            var relative = self.makeProjectRelativeIfPossible(path);
                            self._viewModel.setDirectoryContents(relative, contents);
                            self._viewModel.setDirectoryOpen(relative, true);
                        });
                    },
                    false
                );
            });
        }
    };

    /**
     * Refreshes the contents of the tree.
     *
     * @return {$.Promise} resolved when the tree has been refreshed
     */
    ProjectModel.prototype.refresh = function () {
        var projectRoot = this.projectRoot,
            openNodes   = this.getOpenNodes(),
            self        = this,
            selections  = this._selections,
            viewModel   = this._viewModel,
            deferred    = new $.Deferred();

        this.setProjectRoot(projectRoot).then(function () {
            self.reopenNodes(openNodes).then(function () {
                if (selections.selected) {
                    viewModel.moveMarker("selected", null, self.makeProjectRelativeIfPossible(selections.selected));
                }

                if (selections.context) {
                    viewModel.moveMarker("context", null, self.makeProjectRelativeIfPossible(selections.context));
                }

                if (selections.rename) {
                    viewModel.moveMarker("rename", null, self.makeProjectRelativeIfPossible(selections.rename));
                }

                deferred.resolve();
            });
        });

        return deferred.promise();
    };

    /**
     * Handles filesystem change events and prepares the update for the view model.
     *
     * @param {?(File|Directory)} entry File or Directory changed
     * @param {Array.<FileSystemEntry>=} added If entry is a Directory, contains zero or more added children
     * @param {Array.<FileSystemEntry>=} removed If entry is a Directory, contains zero or more removed
     */
    ProjectModel.prototype.handleFSEvent = function (entry, added, removed) {
        this._resetCache();

        if (!entry) {
            this.refresh();
            return;
        }

        if (!this.isWithinProject(entry)) {
            return;
        }

        var changes = {},
            self = this;

        if (entry.isFile) {
            changes.changed = [
                this.makeProjectRelativeIfPossible(entry.fullPath)
            ];
        } else {
            // Special case: a directory passed in without added and removed values
            // appears to be new.
            if (!added && !removed) {
                this._viewModel.ensureDirectoryExists(this.makeProjectRelativeIfPossible(entry.fullPath));
            }
        }

        if (added) {
            changes.added = added.map(function (entry) {
                return self.makeProjectRelativeIfPossible(entry.fullPath);
            });
        }

        if (removed) {
            if (this._selections.selected &&
                    _.find(removed, { fullPath: this._selections.selected })) {
                this.setSelected(null);
            }

            if (this._selections.rename &&
                    _.find(removed, { fullPath: this._selections.rename.path })) {
                this.cancelRename();
            }

            if (this._selections.context &&
                    _.find(removed, { fullPath: this._selections.context })) {
                this.setContext(null);
            }
            changes.removed = removed.map(function (entry) {
                return self.makeProjectRelativeIfPossible(entry.fullPath);
            });
        }

        this._viewModel.processChanges(changes);
    };

    /**
     * Closes the directory at path and recursively closes all of its children.
     *
     * @param {string} path Path of subtree to close
     */
    ProjectModel.prototype.closeSubtree = function (path) {
        this._viewModel.closeSubtree(this.makeProjectRelativeIfPossible(path));
    };

    /**
     * Toggle the open state of subdirectories.
     * @param {!string}  path        parent directory
     * @param {boolean} openOrClose  true to open directory, false to close
     * @return {$.Promise} promise resolved when the directories are open
     */
    ProjectModel.prototype.toggleSubdirectories = function (path, openOrClose) {
        var self = this,
            d = new $.Deferred();

        this.setDirectoryOpen(path, true).then(function () {
            var projectRelativePath = self.makeProjectRelativeIfPossible(path),
                childNodes = self._viewModel.getChildDirectories(projectRelativePath);

            Async.doInParallel(childNodes, function (node) {
                return self.setDirectoryOpen(path + node, openOrClose);
            }, true).then(function () {
                d.resolve();
            }, function (err) {
                d.reject(err);
            });
        });

        return d.promise();
    };

    /**
     * Although Brackets is generally standardized on folder paths with a trailing "/", some APIs here
     * receive project paths without "/" due to legacy preference storage formats, etc.
     * @param {!string} fullPath  Path that may or may not end in "/"
     * @return {!string} Path that ends in "/"
     */
    function _ensureTrailingSlash(fullPath) {
        if (_pathIsFile(fullPath)) {
            return fullPath + "/";
        }
        return fullPath;
    }

    /**
     * @private
     *
     * Returns the full path to the welcome project, which we open on first launch.
     *
     * @param {string} sampleUrl URL for getting started project
     * @param {string} initialPath Path to Brackets directory (see FileUtils.getNativeBracketsDirectoryPath())
     * @return {!string} fullPath reference
     */
    function _getWelcomeProjectPath(sampleUrl, initialPath) {
        if (sampleUrl) {
            // Back up one more folder. The samples folder is assumed to be at the same level as
            // the src folder, and the sampleUrl is relative to the samples folder.
            initialPath = initialPath.substr(0, initialPath.lastIndexOf("/")) + "/samples/" + sampleUrl;
        }

        return _ensureTrailingSlash(initialPath); // paths above weren't canonical
    }

    /**
     * @private
     *
     * Adds the path to the list of welcome projects we've ever seen, if not on the list already.
     *
     * @param {string} path Path to possibly add
     * @param {Array.<string>=} currentProjects Array of current welcome projects
     * @return {Array.<string>} New array of welcome projects with the additional project added
     */
    function _addWelcomeProjectPath(path, currentProjects) {
        var pathNoSlash = FileUtils.stripTrailingSlash(path);  // "welcomeProjects" pref has standardized on no trailing "/"

        var newProjects;

        if (currentProjects) {
            newProjects = _.clone(currentProjects);
        } else {
            newProjects = [];
        }

        if (newProjects.indexOf(pathNoSlash) === -1) {
            newProjects.push(pathNoSlash);
        }
        return newProjects;
    }

    /**
     * Returns true if the given path is the same as one of the welcome projects we've previously opened,
     * or the one for the current build.
     *
     * @param {string} path Path to check to see if it's a welcome project
     * @param {string} welcomeProjectPath Current welcome project path
     * @param {Array.<string>=} welcomeProjects All known welcome projects
     */
    function _isWelcomeProjectPath(path, welcomeProjectPath, welcomeProjects) {
        if (path === welcomeProjectPath) {
            return true;
        }

        // No match on the current path, and it's not a match if there are no previously known projects
        if (!welcomeProjects) {
            return false;
        }

        var pathNoSlash = FileUtils.stripTrailingSlash(path);  // "welcomeProjects" pref has standardized on no trailing "/"
        return welcomeProjects.indexOf(pathNoSlash) !== -1;
    }

    // Init invalid characters string
    if (brackets.platform === "mac") {
        _invalidChars = "?*|:";
    } else if (brackets.platform === "linux") {
        _invalidChars = "?*|/";
    } else {
        _invalidChars = "/?*:<>\\|\"";  // invalid characters on Windows
    }

    exports._getWelcomeProjectPath  = _getWelcomeProjectPath;
    exports._addWelcomeProjectPath  = _addWelcomeProjectPath;
    exports._isWelcomeProjectPath   = _isWelcomeProjectPath;
    exports._ensureTrailingSlash    = _ensureTrailingSlash;
    exports._shouldShowName         = _shouldShowName;
    exports._invalidChars           = _invalidChars;

    exports.shouldShow              = shouldShow;
    exports.isValidFilename         = isValidFilename;
    exports.EVENT_CHANGE            = EVENT_CHANGE;
    exports.EVENT_SHOULD_SELECT     = EVENT_SHOULD_SELECT;
    exports.EVENT_SHOULD_FOCUS      = EVENT_SHOULD_FOCUS;
    exports.ERROR_CREATION          = ERROR_CREATION;
    exports.ERROR_INVALID_FILENAME  = ERROR_INVALID_FILENAME;
    exports.FILE_RENAMING           = FILE_RENAMING;
    exports.FILE_CREATING           = FILE_CREATING;
    exports.RENAME_CANCELLED        = RENAME_CANCELLED;
    exports.doCreate                = doCreate;
    exports.ProjectModel            = ProjectModel;
});