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node_modules/mongodb/lib/gridfs-stream/download.js

@@ -0,0 +1,415 @@
+'use strict';
+
+var stream = require('stream'),
+  util = require('util');
+
+module.exports = GridFSBucketReadStream;
+
+/**
+ * A readable stream that enables you to read buffers from GridFS.
+ *
+ * Do not instantiate this class directly. Use `openDownloadStream()` instead.
+ *
+ * @class
+ * @param {Collection} chunks Handle for chunks collection
+ * @param {Collection} files Handle for files collection
+ * @param {Object} readPreference The read preference to use
+ * @param {Object} filter The query to use to find the file document
+ * @param {Object} [options] Optional settings.
+ * @param {Number} [options.sort] Optional sort for the file find query
+ * @param {Number} [options.skip] Optional skip for the file find query
+ * @param {Number} [options.start] Optional 0-based offset in bytes to start streaming from
+ * @param {Number} [options.end] Optional 0-based offset in bytes to stop streaming before
+ * @fires GridFSBucketReadStream#error
+ * @fires GridFSBucketReadStream#file
+ * @return {GridFSBucketReadStream} a GridFSBucketReadStream instance.
+ */
+
+function GridFSBucketReadStream(chunks, files, readPreference, filter, options) {
+  this.s = {
+    bytesRead: 0,
+    chunks: chunks,
+    cursor: null,
+    expected: 0,
+    files: files,
+    filter: filter,
+    init: false,
+    expectedEnd: 0,
+    file: null,
+    options: options,
+    readPreference: readPreference
+  };
+
+  stream.Readable.call(this);
+}
+
+util.inherits(GridFSBucketReadStream, stream.Readable);
+
+/**
+ * An error occurred
+ *
+ * @event GridFSBucketReadStream#error
+ * @type {Error}
+ */
+
+/**
+ * Fires when the stream loaded the file document corresponding to the
+ * provided id.
+ *
+ * @event GridFSBucketReadStream#file
+ * @type {object}
+ */
+
+/**
+ * Emitted when a chunk of data is available to be consumed.
+ *
+ * @event GridFSBucketReadStream#data
+ * @type {object}
+ */
+
+/**
+ * Fired when the stream is exhausted (no more data events).
+ *
+ * @event GridFSBucketReadStream#end
+ * @type {object}
+ */
+
+/**
+ * Fired when the stream is exhausted and the underlying cursor is killed
+ *
+ * @event GridFSBucketReadStream#close
+ * @type {object}
+ */
+
+/**
+ * Reads from the cursor and pushes to the stream.
+ * @method
+ */
+
+GridFSBucketReadStream.prototype._read = function() {
+  var _this = this;
+  if (this.destroyed) {
+    return;
+  }
+
+  waitForFile(_this, function() {
+    doRead(_this);
+  });
+};
+
+/**
+ * Sets the 0-based offset in bytes to start streaming from. Throws
+ * an error if this stream has entered flowing mode
+ * (e.g. if you've already called `on('data')`)
+ * @method
+ * @param {Number} start Offset in bytes to start reading at
+ * @return {GridFSBucketReadStream}
+ */
+
+GridFSBucketReadStream.prototype.start = function(start) {
+  throwIfInitialized(this);
+  this.s.options.start = start;
+  return this;
+};
+
+/**
+ * Sets the 0-based offset in bytes to start streaming from. Throws
+ * an error if this stream has entered flowing mode
+ * (e.g. if you've already called `on('data')`)
+ * @method
+ * @param {Number} end Offset in bytes to stop reading at
+ * @return {GridFSBucketReadStream}
+ */
+
+GridFSBucketReadStream.prototype.end = function(end) {
+  throwIfInitialized(this);
+  this.s.options.end = end;
+  return this;
+};
+
+/**
+ * Marks this stream as aborted (will never push another `data` event)
+ * and kills the underlying cursor. Will emit the 'end' event, and then
+ * the 'close' event once the cursor is successfully killed.
+ *
+ * @method
+ * @param {GridFSBucket~errorCallback} [callback] called when the cursor is successfully closed or an error occurred.
+ * @fires GridFSBucketWriteStream#close
+ * @fires GridFSBucketWriteStream#end
+ */
+
+GridFSBucketReadStream.prototype.abort = function(callback) {
+  var _this = this;
+  this.push(null);
+  this.destroyed = true;
+  if (this.s.cursor) {
+    this.s.cursor.close(function(error) {
+      _this.emit('close');
+      callback && callback(error);
+    });
+  } else {
+    if (!this.s.init) {
+      // If not initialized, fire close event because we will never
+      // get a cursor
+      _this.emit('close');
+    }
+    callback && callback();
+  }
+};
+
+/**
+ * @ignore
+ */
+
+function throwIfInitialized(self) {
+  if (self.s.init) {
+    throw new Error('You cannot change options after the stream has entered' + 'flowing mode!');
+  }
+}
+
+/**
+ * @ignore
+ */
+
+function doRead(_this) {
+  if (_this.destroyed) {
+    return;
+  }
+
+  _this.s.cursor.next(function(error, doc) {
+    if (_this.destroyed) {
+      return;
+    }
+    if (error) {
+      return __handleError(_this, error);
+    }
+    if (!doc) {
+      _this.push(null);
+      return _this.s.cursor.close(function(error) {
+        if (error) {
+          return __handleError(_this, error);
+        }
+        _this.emit('close');
+      });
+    }
+
+    var bytesRemaining = _this.s.file.length - _this.s.bytesRead;
+    var expectedN = _this.s.expected++;
+    var expectedLength = Math.min(_this.s.file.chunkSize, bytesRemaining);
+
+    if (doc.n > expectedN) {
+      var errmsg = 'ChunkIsMissing: Got unexpected n: ' + doc.n + ', expected: ' + expectedN;
+      return __handleError(_this, new Error(errmsg));
+    }
+
+    if (doc.n < expectedN) {
+      errmsg = 'ExtraChunk: Got unexpected n: ' + doc.n + ', expected: ' + expectedN;
+      return __handleError(_this, new Error(errmsg));
+    }
+
+    var buf = Buffer.isBuffer(doc.data) ? doc.data : doc.data.buffer;
+
+    if (buf.length !== expectedLength) {
+      if (bytesRemaining <= 0) {
+        errmsg = 'ExtraChunk: Got unexpected n: ' + doc.n;
+        return __handleError(_this, new Error(errmsg));
+      }
+
+      errmsg =
+        'ChunkIsWrongSize: Got unexpected length: ' + buf.length + ', expected: ' + expectedLength;
+      return __handleError(_this, new Error(errmsg));
+    }
+
+    _this.s.bytesRead += buf.length;
+
+    if (buf.length === 0) {
+      return _this.push(null);
+    }
+
+    var sliceStart = null;
+    var sliceEnd = null;
+
+    if (_this.s.bytesToSkip != null) {
+      sliceStart = _this.s.bytesToSkip;
+      _this.s.bytesToSkip = 0;
+    }
+
+    if (expectedN === _this.s.expectedEnd && _this.s.bytesToTrim != null) {
+      sliceEnd = _this.s.bytesToTrim;
+    }
+
+    // If the remaining amount of data left is < chunkSize read the right amount of data
+    if (_this.s.options.end && _this.s.options.end - _this.s.bytesToSkip < buf.length) {
+      sliceEnd = _this.s.options.end - _this.s.bytesToSkip;
+    }
+
+    if (sliceStart != null || sliceEnd != null) {
+      buf = buf.slice(sliceStart || 0, sliceEnd || buf.length);
+    }
+
+    _this.push(buf);
+  });
+}
+
+/**
+ * @ignore
+ */
+
+function init(self) {
+  var findOneOptions = {};
+  if (self.s.readPreference) {
+    findOneOptions.readPreference = self.s.readPreference;
+  }
+  if (self.s.options && self.s.options.sort) {
+    findOneOptions.sort = self.s.options.sort;
+  }
+  if (self.s.options && self.s.options.skip) {
+    findOneOptions.skip = self.s.options.skip;
+  }
+
+  self.s.files.findOne(self.s.filter, findOneOptions, function(error, doc) {
+    if (error) {
+      return __handleError(self, error);
+    }
+    if (!doc) {
+      var identifier = self.s.filter._id ? self.s.filter._id.toString() : self.s.filter.filename;
+      var errmsg = 'FileNotFound: file ' + identifier + ' was not found';
+      var err = new Error(errmsg);
+      err.code = 'ENOENT';
+      return __handleError(self, err);
+    }
+
+    // If document is empty, kill the stream immediately and don't
+    // execute any reads
+    if (doc.length <= 0) {
+      self.push(null);
+      return;
+    }
+
+    if (self.destroyed) {
+      // If user destroys the stream before we have a cursor, wait
+      // until the query is done to say we're 'closed' because we can't
+      // cancel a query.
+      self.emit('close');
+      return;
+    }
+
+    self.s.bytesToSkip = handleStartOption(self, doc, self.s.options);
+
+    var filter = { files_id: doc._id };
+
+    // Currently (MongoDB 3.4.4) skip function does not support the index,
+    // it needs to retrieve all the documents first and then skip them. (CS-25811)
+    // As work around we use $gte on the "n" field.
+    if (self.s.options && self.s.options.start != null) {
+      var skip = Math.floor(self.s.options.start / doc.chunkSize);
+      if (skip > 0) {
+        filter['n'] = { $gte: skip };
+      }
+    }
+    self.s.cursor = self.s.chunks.find(filter).sort({ n: 1 });
+
+    if (self.s.readPreference) {
+      self.s.cursor.setReadPreference(self.s.readPreference);
+    }
+
+    self.s.expectedEnd = Math.ceil(doc.length / doc.chunkSize);
+    self.s.file = doc;
+    self.s.bytesToTrim = handleEndOption(self, doc, self.s.cursor, self.s.options);
+    self.emit('file', doc);
+  });
+}
+
+/**
+ * @ignore
+ */
+
+function waitForFile(_this, callback) {
+  if (_this.s.file) {
+    return callback();
+  }
+
+  if (!_this.s.init) {
+    init(_this);
+    _this.s.init = true;
+  }
+
+  _this.once('file', function() {
+    callback();
+  });
+}
+
+/**
+ * @ignore
+ */
+
+function handleStartOption(stream, doc, options) {
+  if (options && options.start != null) {
+    if (options.start > doc.length) {
+      throw new Error(
+        'Stream start (' +
+          options.start +
+          ') must not be ' +
+          'more than the length of the file (' +
+          doc.length +
+          ')'
+      );
+    }
+    if (options.start < 0) {
+      throw new Error('Stream start (' + options.start + ') must not be ' + 'negative');
+    }
+    if (options.end != null && options.end < options.start) {
+      throw new Error(
+        'Stream start (' +
+          options.start +
+          ') must not be ' +
+          'greater than stream end (' +
+          options.end +
+          ')'
+      );
+    }
+
+    stream.s.bytesRead = Math.floor(options.start / doc.chunkSize) * doc.chunkSize;
+    stream.s.expected = Math.floor(options.start / doc.chunkSize);
+
+    return options.start - stream.s.bytesRead;
+  }
+}
+
+/**
+ * @ignore
+ */
+
+function handleEndOption(stream, doc, cursor, options) {
+  if (options && options.end != null) {
+    if (options.end > doc.length) {
+      throw new Error(
+        'Stream end (' +
+          options.end +
+          ') must not be ' +
+          'more than the length of the file (' +
+          doc.length +
+          ')'
+      );
+    }
+    if (options.start < 0) {
+      throw new Error('Stream end (' + options.end + ') must not be ' + 'negative');
+    }
+
+    var start = options.start != null ? Math.floor(options.start / doc.chunkSize) : 0;
+
+    cursor.limit(Math.ceil(options.end / doc.chunkSize) - start);
+
+    stream.s.expectedEnd = Math.ceil(options.end / doc.chunkSize);
+
+    return Math.ceil(options.end / doc.chunkSize) * doc.chunkSize - options.end;
+  }
+}
+
+/**
+ * @ignore
+ */
+
+function __handleError(_this, error) {
+  _this.emit('error', error);
+}

node_modules/mongodb/lib/gridfs-stream/index.js

@@ -0,0 +1,358 @@
+'use strict';
+
+var Emitter = require('events').EventEmitter;
+var GridFSBucketReadStream = require('./download');
+var GridFSBucketWriteStream = require('./upload');
+var shallowClone = require('../utils').shallowClone;
+var toError = require('../utils').toError;
+var util = require('util');
+var executeOperation = require('../utils').executeOperation;
+
+var DEFAULT_GRIDFS_BUCKET_OPTIONS = {
+  bucketName: 'fs',
+  chunkSizeBytes: 255 * 1024
+};
+
+module.exports = GridFSBucket;
+
+/**
+ * Constructor for a streaming GridFS interface
+ * @class
+ * @param {Db} db A db handle
+ * @param {object} [options] Optional settings.
+ * @param {string} [options.bucketName="fs"] The 'files' and 'chunks' collections will be prefixed with the bucket name followed by a dot.
+ * @param {number} [options.chunkSizeBytes=255 * 1024] Number of bytes stored in each chunk. Defaults to 255KB
+ * @param {object} [options.writeConcern] Optional write concern to be passed to write operations, for instance `{ w: 1 }`
+ * @param {object} [options.readPreference] Optional read preference to be passed to read operations
+ * @fires GridFSBucketWriteStream#index
+ * @return {GridFSBucket}
+ */
+
+function GridFSBucket(db, options) {
+  Emitter.apply(this);
+  this.setMaxListeners(0);
+
+  if (options && typeof options === 'object') {
+    options = shallowClone(options);
+    var keys = Object.keys(DEFAULT_GRIDFS_BUCKET_OPTIONS);
+    for (var i = 0; i < keys.length; ++i) {
+      if (!options[keys[i]]) {
+        options[keys[i]] = DEFAULT_GRIDFS_BUCKET_OPTIONS[keys[i]];
+      }
+    }
+  } else {
+    options = DEFAULT_GRIDFS_BUCKET_OPTIONS;
+  }
+
+  this.s = {
+    db: db,
+    options: options,
+    _chunksCollection: db.collection(options.bucketName + '.chunks'),
+    _filesCollection: db.collection(options.bucketName + '.files'),
+    checkedIndexes: false,
+    calledOpenUploadStream: false,
+    promiseLibrary: db.s.promiseLibrary || Promise
+  };
+}
+
+util.inherits(GridFSBucket, Emitter);
+
+/**
+ * When the first call to openUploadStream is made, the upload stream will
+ * check to see if it needs to create the proper indexes on the chunks and
+ * files collections. This event is fired either when 1) it determines that
+ * no index creation is necessary, 2) when it successfully creates the
+ * necessary indexes.
+ *
+ * @event GridFSBucket#index
+ * @type {Error}
+ */
+
+/**
+ * Returns a writable stream (GridFSBucketWriteStream) for writing
+ * buffers to GridFS. The stream's 'id' property contains the resulting
+ * file's id.
+ * @method
+ * @param {string} filename The value of the 'filename' key in the files doc
+ * @param {object} [options] Optional settings.
+ * @param {number} [options.chunkSizeBytes] Optional overwrite this bucket's chunkSizeBytes for this file
+ * @param {object} [options.metadata] Optional object to store in the file document's `metadata` field
+ * @param {string} [options.contentType] Optional string to store in the file document's `contentType` field
+ * @param {array} [options.aliases] Optional array of strings to store in the file document's `aliases` field
+ * @param {boolean} [options.disableMD5=false] If true, disables adding an md5 field to file data
+ * @return {GridFSBucketWriteStream}
+ */
+
+GridFSBucket.prototype.openUploadStream = function(filename, options) {
+  if (options) {
+    options = shallowClone(options);
+  } else {
+    options = {};
+  }
+  if (!options.chunkSizeBytes) {
+    options.chunkSizeBytes = this.s.options.chunkSizeBytes;
+  }
+  return new GridFSBucketWriteStream(this, filename, options);
+};
+
+/**
+ * Returns a writable stream (GridFSBucketWriteStream) for writing
+ * buffers to GridFS for a custom file id. The stream's 'id' property contains the resulting
+ * file's id.
+ * @method
+ * @param {string|number|object} id A custom id used to identify the file
+ * @param {string} filename The value of the 'filename' key in the files doc
+ * @param {object} [options] Optional settings.
+ * @param {number} [options.chunkSizeBytes] Optional overwrite this bucket's chunkSizeBytes for this file
+ * @param {object} [options.metadata] Optional object to store in the file document's `metadata` field
+ * @param {string} [options.contentType] Optional string to store in the file document's `contentType` field
+ * @param {array} [options.aliases] Optional array of strings to store in the file document's `aliases` field
+ * @param {boolean} [options.disableMD5=false] If true, disables adding an md5 field to file data
+ * @return {GridFSBucketWriteStream}
+ */
+
+GridFSBucket.prototype.openUploadStreamWithId = function(id, filename, options) {
+  if (options) {
+    options = shallowClone(options);
+  } else {
+    options = {};
+  }
+
+  if (!options.chunkSizeBytes) {
+    options.chunkSizeBytes = this.s.options.chunkSizeBytes;
+  }
+
+  options.id = id;
+
+  return new GridFSBucketWriteStream(this, filename, options);
+};
+
+/**
+ * Returns a readable stream (GridFSBucketReadStream) for streaming file
+ * data from GridFS.
+ * @method
+ * @param {ObjectId} id The id of the file doc
+ * @param {Object} [options] Optional settings.
+ * @param {Number} [options.start] Optional 0-based offset in bytes to start streaming from
+ * @param {Number} [options.end] Optional 0-based offset in bytes to stop streaming before
+ * @return {GridFSBucketReadStream}
+ */
+
+GridFSBucket.prototype.openDownloadStream = function(id, options) {
+  var filter = { _id: id };
+  options = {
+    start: options && options.start,
+    end: options && options.end
+  };
+
+  return new GridFSBucketReadStream(
+    this.s._chunksCollection,
+    this.s._filesCollection,
+    this.s.options.readPreference,
+    filter,
+    options
+  );
+};
+
+/**
+ * Deletes a file with the given id
+ * @method
+ * @param {ObjectId} id The id of the file doc
+ * @param {GridFSBucket~errorCallback} [callback]
+ */
+
+GridFSBucket.prototype.delete = function(id, callback) {
+  return executeOperation(this.s.db.s.topology, _delete, [this, id, callback], {
+    skipSessions: true
+  });
+};
+
+/**
+ * @ignore
+ */
+
+function _delete(_this, id, callback) {
+  _this.s._filesCollection.deleteOne({ _id: id }, function(error, res) {
+    if (error) {
+      return callback(error);
+    }
+
+    _this.s._chunksCollection.deleteMany({ files_id: id }, function(error) {
+      if (error) {
+        return callback(error);
+      }
+
+      // Delete orphaned chunks before returning FileNotFound
+      if (!res.result.n) {
+        var errmsg = 'FileNotFound: no file with id ' + id + ' found';
+        return callback(new Error(errmsg));
+      }
+
+      callback();
+    });
+  });
+}
+
+/**
+ * Convenience wrapper around find on the files collection
+ * @method
+ * @param {Object} filter
+ * @param {Object} [options] Optional settings for cursor
+ * @param {number} [options.batchSize] Optional batch size for cursor
+ * @param {number} [options.limit] Optional limit for cursor
+ * @param {number} [options.maxTimeMS] Optional maxTimeMS for cursor
+ * @param {boolean} [options.noCursorTimeout] Optionally set cursor's `noCursorTimeout` flag
+ * @param {number} [options.skip] Optional skip for cursor
+ * @param {object} [options.sort] Optional sort for cursor
+ * @return {Cursor}
+ */
+
+GridFSBucket.prototype.find = function(filter, options) {
+  filter = filter || {};
+  options = options || {};
+
+  var cursor = this.s._filesCollection.find(filter);
+
+  if (options.batchSize != null) {
+    cursor.batchSize(options.batchSize);
+  }
+  if (options.limit != null) {
+    cursor.limit(options.limit);
+  }
+  if (options.maxTimeMS != null) {
+    cursor.maxTimeMS(options.maxTimeMS);
+  }
+  if (options.noCursorTimeout != null) {
+    cursor.addCursorFlag('noCursorTimeout', options.noCursorTimeout);
+  }
+  if (options.skip != null) {
+    cursor.skip(options.skip);
+  }
+  if (options.sort != null) {
+    cursor.sort(options.sort);
+  }
+
+  return cursor;
+};
+
+/**
+ * Returns a readable stream (GridFSBucketReadStream) for streaming the
+ * file with the given name from GridFS. If there are multiple files with
+ * the same name, this will stream the most recent file with the given name
+ * (as determined by the `uploadDate` field). You can set the `revision`
+ * option to change this behavior.
+ * @method
+ * @param {String} filename The name of the file to stream
+ * @param {Object} [options] Optional settings
+ * @param {number} [options.revision=-1] The revision number relative to the oldest file with the given filename. 0 gets you the oldest file, 1 gets you the 2nd oldest, -1 gets you the newest.
+ * @param {Number} [options.start] Optional 0-based offset in bytes to start streaming from
+ * @param {Number} [options.end] Optional 0-based offset in bytes to stop streaming before
+ * @return {GridFSBucketReadStream}
+ */
+
+GridFSBucket.prototype.openDownloadStreamByName = function(filename, options) {
+  var sort = { uploadDate: -1 };
+  var skip = null;
+  if (options && options.revision != null) {
+    if (options.revision >= 0) {
+      sort = { uploadDate: 1 };
+      skip = options.revision;
+    } else {
+      skip = -options.revision - 1;
+    }
+  }
+
+  var filter = { filename: filename };
+  options = {
+    sort: sort,
+    skip: skip,
+    start: options && options.start,
+    end: options && options.end
+  };
+  return new GridFSBucketReadStream(
+    this.s._chunksCollection,
+    this.s._filesCollection,
+    this.s.options.readPreference,
+    filter,
+    options
+  );
+};
+
+/**
+ * Renames the file with the given _id to the given string
+ * @method
+ * @param {ObjectId} id the id of the file to rename
+ * @param {String} filename new name for the file
+ * @param {GridFSBucket~errorCallback} [callback]
+ */
+
+GridFSBucket.prototype.rename = function(id, filename, callback) {
+  return executeOperation(this.s.db.s.topology, _rename, [this, id, filename, callback], {
+    skipSessions: true
+  });
+};
+
+/**
+ * @ignore
+ */
+
+function _rename(_this, id, filename, callback) {
+  var filter = { _id: id };
+  var update = { $set: { filename: filename } };
+  _this.s._filesCollection.updateOne(filter, update, function(error, res) {
+    if (error) {
+      return callback(error);
+    }
+    if (!res.result.n) {
+      return callback(toError('File with id ' + id + ' not found'));
+    }
+    callback();
+  });
+}
+
+/**
+ * Removes this bucket's files collection, followed by its chunks collection.
+ * @method
+ * @param {GridFSBucket~errorCallback} [callback]
+ */
+
+GridFSBucket.prototype.drop = function(callback) {
+  return executeOperation(this.s.db.s.topology, _drop, [this, callback], {
+    skipSessions: true
+  });
+};
+
+/**
+ * Return the db logger
+ * @method
+ * @return {Logger} return the db logger
+ * @ignore
+ */
+GridFSBucket.prototype.getLogger = function() {
+  return this.s.db.s.logger;
+};
+
+/**
+ * @ignore
+ */
+
+function _drop(_this, callback) {
+  _this.s._filesCollection.drop(function(error) {
+    if (error) {
+      return callback(error);
+    }
+    _this.s._chunksCollection.drop(function(error) {
+      if (error) {
+        return callback(error);
+      }
+
+      return callback();
+    });
+  });
+}
+
+/**
+ * Callback format for all GridFSBucket methods that can accept a callback.
+ * @callback GridFSBucket~errorCallback
+ * @param {MongoError} error An error instance representing any errors that occurred
+ */

node_modules/mongodb/lib/gridfs-stream/upload.js

@@ -0,0 +1,538 @@
+'use strict';
+
+var core = require('mongodb-core');
+var crypto = require('crypto');
+var stream = require('stream');
+var util = require('util');
+var Buffer = require('safe-buffer').Buffer;
+
+var ERROR_NAMESPACE_NOT_FOUND = 26;
+
+module.exports = GridFSBucketWriteStream;
+
+/**
+ * A writable stream that enables you to write buffers to GridFS.
+ *
+ * Do not instantiate this class directly. Use `openUploadStream()` instead.
+ *
+ * @class
+ * @param {GridFSBucket} bucket Handle for this stream's corresponding bucket
+ * @param {string} filename The value of the 'filename' key in the files doc
+ * @param {object} [options] Optional settings.
+ * @param {string|number|object} [options.id] Custom file id for the GridFS file.
+ * @param {number} [options.chunkSizeBytes] The chunk size to use, in bytes
+ * @param {number} [options.w] The write concern
+ * @param {number} [options.wtimeout] The write concern timeout
+ * @param {number} [options.j] The journal write concern
+ * @param {boolean} [options.disableMD5=false] If true, disables adding an md5 field to file data
+ * @fires GridFSBucketWriteStream#error
+ * @fires GridFSBucketWriteStream#finish
+ * @return {GridFSBucketWriteStream} a GridFSBucketWriteStream instance.
+ */
+
+function GridFSBucketWriteStream(bucket, filename, options) {
+  options = options || {};
+  this.bucket = bucket;
+  this.chunks = bucket.s._chunksCollection;
+  this.filename = filename;
+  this.files = bucket.s._filesCollection;
+  this.options = options;
+  // Signals the write is all done
+  this.done = false;
+
+  this.id = options.id ? options.id : core.BSON.ObjectId();
+  this.chunkSizeBytes = this.options.chunkSizeBytes;
+  this.bufToStore = Buffer.alloc(this.chunkSizeBytes);
+  this.length = 0;
+  this.md5 = !options.disableMD5 && crypto.createHash('md5');
+  this.n = 0;
+  this.pos = 0;
+  this.state = {
+    streamEnd: false,
+    outstandingRequests: 0,
+    errored: false,
+    aborted: false,
+    promiseLibrary: this.bucket.s.promiseLibrary
+  };
+
+  if (!this.bucket.s.calledOpenUploadStream) {
+    this.bucket.s.calledOpenUploadStream = true;
+
+    var _this = this;
+    checkIndexes(this, function() {
+      _this.bucket.s.checkedIndexes = true;
+      _this.bucket.emit('index');
+    });
+  }
+}
+
+util.inherits(GridFSBucketWriteStream, stream.Writable);
+
+/**
+ * An error occurred
+ *
+ * @event GridFSBucketWriteStream#error
+ * @type {Error}
+ */
+
+/**
+ * `end()` was called and the write stream successfully wrote the file
+ * metadata and all the chunks to MongoDB.
+ *
+ * @event GridFSBucketWriteStream#finish
+ * @type {object}
+ */
+
+/**
+ * Write a buffer to the stream.
+ *
+ * @method
+ * @param {Buffer} chunk Buffer to write
+ * @param {String} encoding Optional encoding for the buffer
+ * @param {Function} callback Function to call when the chunk was added to the buffer, or if the entire chunk was persisted to MongoDB if this chunk caused a flush.
+ * @return {Boolean} False if this write required flushing a chunk to MongoDB. True otherwise.
+ */
+
+GridFSBucketWriteStream.prototype.write = function(chunk, encoding, callback) {
+  var _this = this;
+  return waitForIndexes(this, function() {
+    return doWrite(_this, chunk, encoding, callback);
+  });
+};
+
+/**
+ * Places this write stream into an aborted state (all future writes fail)
+ * and deletes all chunks that have already been written.
+ *
+ * @method
+ * @param {GridFSBucket~errorCallback} callback called when chunks are successfully removed or error occurred
+ * @return {Promise} if no callback specified
+ */
+
+GridFSBucketWriteStream.prototype.abort = function(callback) {
+  if (this.state.streamEnd) {
+    var error = new Error('Cannot abort a stream that has already completed');
+    if (typeof callback === 'function') {
+      return callback(error);
+    }
+    return this.state.promiseLibrary.reject(error);
+  }
+  if (this.state.aborted) {
+    error = new Error('Cannot call abort() on a stream twice');
+    if (typeof callback === 'function') {
+      return callback(error);
+    }
+    return this.state.promiseLibrary.reject(error);
+  }
+  this.state.aborted = true;
+  this.chunks.deleteMany({ files_id: this.id }, function(error) {
+    if (typeof callback === 'function') callback(error);
+  });
+};
+
+/**
+ * Tells the stream that no more data will be coming in. The stream will
+ * persist the remaining data to MongoDB, write the files document, and
+ * then emit a 'finish' event.
+ *
+ * @method
+ * @param {Buffer} chunk Buffer to write
+ * @param {String} encoding Optional encoding for the buffer
+ * @param {Function} callback Function to call when all files and chunks have been persisted to MongoDB
+ */
+
+GridFSBucketWriteStream.prototype.end = function(chunk, encoding, callback) {
+  var _this = this;
+  if (typeof chunk === 'function') {
+    (callback = chunk), (chunk = null), (encoding = null);
+  } else if (typeof encoding === 'function') {
+    (callback = encoding), (encoding = null);
+  }
+
+  if (checkAborted(this, callback)) {
+    return;
+  }
+  this.state.streamEnd = true;
+
+  if (callback) {
+    this.once('finish', function(result) {
+      callback(null, result);
+    });
+  }
+
+  if (!chunk) {
+    waitForIndexes(this, function() {
+      writeRemnant(_this);
+    });
+    return;
+  }
+
+  this.write(chunk, encoding, function() {
+    writeRemnant(_this);
+  });
+};
+
+/**
+ * @ignore
+ */
+
+function __handleError(_this, error, callback) {
+  if (_this.state.errored) {
+    return;
+  }
+  _this.state.errored = true;
+  if (callback) {
+    return callback(error);
+  }
+  _this.emit('error', error);
+}
+
+/**
+ * @ignore
+ */
+
+function createChunkDoc(filesId, n, data) {
+  return {
+    _id: core.BSON.ObjectId(),
+    files_id: filesId,
+    n: n,
+    data: data
+  };
+}
+
+/**
+ * @ignore
+ */
+
+function checkChunksIndex(_this, callback) {
+  _this.chunks.listIndexes().toArray(function(error, indexes) {
+    if (error) {
+      // Collection doesn't exist so create index
+      if (error.code === ERROR_NAMESPACE_NOT_FOUND) {
+        var index = { files_id: 1, n: 1 };
+        _this.chunks.createIndex(index, { background: false, unique: true }, function(error) {
+          if (error) {
+            return callback(error);
+          }
+
+          callback();
+        });
+        return;
+      }
+      return callback(error);
+    }
+
+    var hasChunksIndex = false;
+    indexes.forEach(function(index) {
+      if (index.key) {
+        var keys = Object.keys(index.key);
+        if (keys.length === 2 && index.key.files_id === 1 && index.key.n === 1) {
+          hasChunksIndex = true;
+        }
+      }
+    });
+
+    if (hasChunksIndex) {
+      callback();
+    } else {
+      index = { files_id: 1, n: 1 };
+      var indexOptions = getWriteOptions(_this);
+
+      indexOptions.background = false;
+      indexOptions.unique = true;
+
+      _this.chunks.createIndex(index, indexOptions, function(error) {
+        if (error) {
+          return callback(error);
+        }
+
+        callback();
+      });
+    }
+  });
+}
+
+/**
+ * @ignore
+ */
+
+function checkDone(_this, callback) {
+  if (_this.done) return true;
+  if (_this.state.streamEnd && _this.state.outstandingRequests === 0 && !_this.state.errored) {
+    // Set done so we dont' trigger duplicate createFilesDoc
+    _this.done = true;
+    // Create a new files doc
+    var filesDoc = createFilesDoc(
+      _this.id,
+      _this.length,
+      _this.chunkSizeBytes,
+      _this.md5 && _this.md5.digest('hex'),
+      _this.filename,
+      _this.options.contentType,
+      _this.options.aliases,
+      _this.options.metadata
+    );
+
+    if (checkAborted(_this, callback)) {
+      return false;
+    }
+
+    _this.files.insertOne(filesDoc, getWriteOptions(_this), function(error) {
+      if (error) {
+        return __handleError(_this, error, callback);
+      }
+      _this.emit('finish', filesDoc);
+    });
+
+    return true;
+  }
+
+  return false;
+}
+
+/**
+ * @ignore
+ */
+
+function checkIndexes(_this, callback) {
+  _this.files.findOne({}, { _id: 1 }, function(error, doc) {
+    if (error) {
+      return callback(error);
+    }
+    if (doc) {
+      return callback();
+    }
+
+    _this.files.listIndexes().toArray(function(error, indexes) {
+      if (error) {
+        // Collection doesn't exist so create index
+        if (error.code === ERROR_NAMESPACE_NOT_FOUND) {
+          var index = { filename: 1, uploadDate: 1 };
+          _this.files.createIndex(index, { background: false }, function(error) {
+            if (error) {
+              return callback(error);
+            }
+
+            checkChunksIndex(_this, callback);
+          });
+          return;
+        }
+        return callback(error);
+      }
+
+      var hasFileIndex = false;
+      indexes.forEach(function(index) {
+        var keys = Object.keys(index.key);
+        if (keys.length === 2 && index.key.filename === 1 && index.key.uploadDate === 1) {
+          hasFileIndex = true;
+        }
+      });
+
+      if (hasFileIndex) {
+        checkChunksIndex(_this, callback);
+      } else {
+        index = { filename: 1, uploadDate: 1 };
+
+        var indexOptions = getWriteOptions(_this);
+
+        indexOptions.background = false;
+
+        _this.files.createIndex(index, indexOptions, function(error) {
+          if (error) {
+            return callback(error);
+          }
+
+          checkChunksIndex(_this, callback);
+        });
+      }
+    });
+  });
+}
+
+/**
+ * @ignore
+ */
+
+function createFilesDoc(_id, length, chunkSize, md5, filename, contentType, aliases, metadata) {
+  var ret = {
+    _id: _id,
+    length: length,
+    chunkSize: chunkSize,
+    uploadDate: new Date(),
+    filename: filename
+  };
+
+  if (md5) {
+    ret.md5 = md5;
+  }
+
+  if (contentType) {
+    ret.contentType = contentType;
+  }
+
+  if (aliases) {
+    ret.aliases = aliases;
+  }
+
+  if (metadata) {
+    ret.metadata = metadata;
+  }
+
+  return ret;
+}
+
+/**
+ * @ignore
+ */
+
+function doWrite(_this, chunk, encoding, callback) {
+  if (checkAborted(_this, callback)) {
+    return false;
+  }
+
+  var inputBuf = Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk, encoding);
+
+  _this.length += inputBuf.length;
+
+  // Input is small enough to fit in our buffer
+  if (_this.pos + inputBuf.length < _this.chunkSizeBytes) {
+    inputBuf.copy(_this.bufToStore, _this.pos);
+    _this.pos += inputBuf.length;
+
+    callback && callback();
+
+    // Note that we reverse the typical semantics of write's return value
+    // to be compatible with node's `.pipe()` function.
+    // True means client can keep writing.
+    return true;
+  }
+
+  // Otherwise, buffer is too big for current chunk, so we need to flush
+  // to MongoDB.
+  var inputBufRemaining = inputBuf.length;
+  var spaceRemaining = _this.chunkSizeBytes - _this.pos;
+  var numToCopy = Math.min(spaceRemaining, inputBuf.length);
+  var outstandingRequests = 0;
+  while (inputBufRemaining > 0) {
+    var inputBufPos = inputBuf.length - inputBufRemaining;
+    inputBuf.copy(_this.bufToStore, _this.pos, inputBufPos, inputBufPos + numToCopy);
+    _this.pos += numToCopy;
+    spaceRemaining -= numToCopy;
+    if (spaceRemaining === 0) {
+      if (_this.md5) {
+        _this.md5.update(_this.bufToStore);
+      }
+      var doc = createChunkDoc(_this.id, _this.n, _this.bufToStore);
+      ++_this.state.outstandingRequests;
+      ++outstandingRequests;
+
+      if (checkAborted(_this, callback)) {
+        return false;
+      }
+
+      _this.chunks.insertOne(doc, getWriteOptions(_this), function(error) {
+        if (error) {
+          return __handleError(_this, error);
+        }
+        --_this.state.outstandingRequests;
+        --outstandingRequests;
+
+        if (!outstandingRequests) {
+          _this.emit('drain', doc);
+          callback && callback();
+          checkDone(_this);
+        }
+      });
+
+      spaceRemaining = _this.chunkSizeBytes;
+      _this.pos = 0;
+      ++_this.n;
+    }
+    inputBufRemaining -= numToCopy;
+    numToCopy = Math.min(spaceRemaining, inputBufRemaining);
+  }
+
+  // Note that we reverse the typical semantics of write's return value
+  // to be compatible with node's `.pipe()` function.
+  // False means the client should wait for the 'drain' event.
+  return false;
+}
+
+/**
+ * @ignore
+ */
+
+function getWriteOptions(_this) {
+  var obj = {};
+  if (_this.options.writeConcern) {
+    obj.w = _this.options.writeConcern.w;
+    obj.wtimeout = _this.options.writeConcern.wtimeout;
+    obj.j = _this.options.writeConcern.j;
+  }
+  return obj;
+}
+
+/**
+ * @ignore
+ */
+
+function waitForIndexes(_this, callback) {
+  if (_this.bucket.s.checkedIndexes) {
+    return callback(false);
+  }
+
+  _this.bucket.once('index', function() {
+    callback(true);
+  });
+
+  return true;
+}
+
+/**
+ * @ignore
+ */
+
+function writeRemnant(_this, callback) {
+  // Buffer is empty, so don't bother to insert
+  if (_this.pos === 0) {
+    return checkDone(_this, callback);
+  }
+
+  ++_this.state.outstandingRequests;
+
+  // Create a new buffer to make sure the buffer isn't bigger than it needs
+  // to be.
+  var remnant = Buffer.alloc(_this.pos);
+  _this.bufToStore.copy(remnant, 0, 0, _this.pos);
+  if (_this.md5) {
+    _this.md5.update(remnant);
+  }
+  var doc = createChunkDoc(_this.id, _this.n, remnant);
+
+  // If the stream was aborted, do not write remnant
+  if (checkAborted(_this, callback)) {
+    return false;
+  }
+
+  _this.chunks.insertOne(doc, getWriteOptions(_this), function(error) {
+    if (error) {
+      return __handleError(_this, error);
+    }
+    --_this.state.outstandingRequests;
+    checkDone(_this);
+  });
+}
+
+/**
+ * @ignore
+ */
+
+function checkAborted(_this, callback) {
+  if (_this.state.aborted) {
+    if (typeof callback === 'function') {
+      callback(new Error('this stream has been aborted'));
+    }
+    return true;
+  }
+  return false;
+}