rm node_modules

2 files changed, 0 insertions, 2157 deletions

diff --git a/node_modules/mongodb/lib/gridfs/chunk.js b/node_modules/mongodb/lib/gridfs/chunk.js
deleted file mode 100644
index d276d72..0000000
--- a/node_modules/mongodb/lib/gridfs/chunk.js
+++ /dev/null
@@ -1,236 +0,0 @@
-'use strict';
-
-var Binary = require('../core').BSON.Binary,
-  ObjectID = require('../core').BSON.ObjectID;
-
-var Buffer = require('safe-buffer').Buffer;
-
-/**
- * Class for representing a single chunk in GridFS.
- *
- * @class
- *
- * @param file {GridStore} The {@link GridStore} object holding this chunk.
- * @param mongoObject {object} The mongo object representation of this chunk.
- *
- * @throws Error when the type of data field for {@link mongoObject} is not
- *     supported. Currently supported types for data field are instances of
- *     {@link String}, {@link Array}, {@link Binary} and {@link Binary}
- *     from the bson module
- *
- * @see Chunk#buildMongoObject
- */
-var Chunk = function(file, mongoObject, writeConcern) {
-  if (!(this instanceof Chunk)) return new Chunk(file, mongoObject);
-
-  this.file = file;
-  var mongoObjectFinal = mongoObject == null ? {} : mongoObject;
-  this.writeConcern = writeConcern || { w: 1 };
-  this.objectId = mongoObjectFinal._id == null ? new ObjectID() : mongoObjectFinal._id;
-  this.chunkNumber = mongoObjectFinal.n == null ? 0 : mongoObjectFinal.n;
-  this.data = new Binary();
-
-  if (typeof mongoObjectFinal.data === 'string') {
-    var buffer = Buffer.alloc(mongoObjectFinal.data.length);
-    buffer.write(mongoObjectFinal.data, 0, mongoObjectFinal.data.length, 'binary');
-    this.data = new Binary(buffer);
-  } else if (Array.isArray(mongoObjectFinal.data)) {
-    buffer = Buffer.alloc(mongoObjectFinal.data.length);
-    var data = mongoObjectFinal.data.join('');
-    buffer.write(data, 0, data.length, 'binary');
-    this.data = new Binary(buffer);
-  } else if (mongoObjectFinal.data && mongoObjectFinal.data._bsontype === 'Binary') {
-    this.data = mongoObjectFinal.data;
-  } else if (!Buffer.isBuffer(mongoObjectFinal.data) && !(mongoObjectFinal.data == null)) {
-    throw Error('Illegal chunk format');
-  }
-
-  // Update position
-  this.internalPosition = 0;
-};
-
-/**
- * Writes a data to this object and advance the read/write head.
- *
- * @param data {string} the data to write
- * @param callback {function(*, GridStore)} This will be called after executing
- *     this method. The first parameter will contain null and the second one
- *     will contain a reference to this object.
- */
-Chunk.prototype.write = function(data, callback) {
-  this.data.write(data, this.internalPosition, data.length, 'binary');
-  this.internalPosition = this.data.length();
-  if (callback != null) return callback(null, this);
-  return this;
-};
-
-/**
- * Reads data and advances the read/write head.
- *
- * @param length {number} The length of data to read.
- *
- * @return {string} The data read if the given length will not exceed the end of
- *     the chunk. Returns an empty String otherwise.
- */
-Chunk.prototype.read = function(length) {
-  // Default to full read if no index defined
-  length = length == null || length === 0 ? this.length() : length;
-
-  if (this.length() - this.internalPosition + 1 >= length) {
-    var data = this.data.read(this.internalPosition, length);
-    this.internalPosition = this.internalPosition + length;
-    return data;
-  } else {
-    return '';
-  }
-};
-
-Chunk.prototype.readSlice = function(length) {
-  if (this.length() - this.internalPosition >= length) {
-    var data = null;
-    if (this.data.buffer != null) {
-      //Pure BSON
-      data = this.data.buffer.slice(this.internalPosition, this.internalPosition + length);
-    } else {
-      //Native BSON
-      data = Buffer.alloc(length);
-      length = this.data.readInto(data, this.internalPosition);
-    }
-    this.internalPosition = this.internalPosition + length;
-    return data;
-  } else {
-    return null;
-  }
-};
-
-/**
- * Checks if the read/write head is at the end.
- *
- * @return {boolean} Whether the read/write head has reached the end of this
- *     chunk.
- */
-Chunk.prototype.eof = function() {
-  return this.internalPosition === this.length() ? true : false;
-};
-
-/**
- * Reads one character from the data of this chunk and advances the read/write
- * head.
- *
- * @return {string} a single character data read if the the read/write head is
- *     not at the end of the chunk. Returns an empty String otherwise.
- */
-Chunk.prototype.getc = function() {
-  return this.read(1);
-};
-
-/**
- * Clears the contents of the data in this chunk and resets the read/write head
- * to the initial position.
- */
-Chunk.prototype.rewind = function() {
-  this.internalPosition = 0;
-  this.data = new Binary();
-};
-
-/**
- * Saves this chunk to the database. Also overwrites existing entries having the
- * same id as this chunk.
- *
- * @param callback {function(*, GridStore)} This will be called after executing
- *     this method. The first parameter will contain null and the second one
- *     will contain a reference to this object.
- */
-Chunk.prototype.save = function(options, callback) {
-  var self = this;
-  if (typeof options === 'function') {
-    callback = options;
-    options = {};
-  }
-
-  self.file.chunkCollection(function(err, collection) {
-    if (err) return callback(err);
-
-    // Merge the options
-    var writeOptions = { upsert: true };
-    for (var name in options) writeOptions[name] = options[name];
-    for (name in self.writeConcern) writeOptions[name] = self.writeConcern[name];
-
-    if (self.data.length() > 0) {
-      self.buildMongoObject(function(mongoObject) {
-        var options = { forceServerObjectId: true };
-        for (var name in self.writeConcern) {
-          options[name] = self.writeConcern[name];
-        }
-
-        collection.replaceOne({ _id: self.objectId }, mongoObject, writeOptions, function(err) {
-          callback(err, self);
-        });
-      });
-    } else {
-      callback(null, self);
-    }
-    // });
-  });
-};
-
-/**
- * Creates a mongoDB object representation of this chunk.
- *
- * @param callback {function(Object)} This will be called after executing this
- *     method. The object will be passed to the first parameter and will have
- *     the structure:
- *
- *        <pre><code>
- *        {
- *          '_id' : , // {number} id for this chunk
- *          'files_id' : , // {number} foreign key to the file collection
- *          'n' : , // {number} chunk number
- *          'data' : , // {bson#Binary} the chunk data itself
- *        }
- *        </code></pre>
- *
- * @see <a href="http://www.mongodb.org/display/DOCS/GridFS+Specification#GridFSSpecification-{{chunks}}">MongoDB GridFS Chunk Object Structure</a>
- */
-Chunk.prototype.buildMongoObject = function(callback) {
-  var mongoObject = {
-    files_id: this.file.fileId,
-    n: this.chunkNumber,
-    data: this.data
-  };
-  // If we are saving using a specific ObjectId
-  if (this.objectId != null) mongoObject._id = this.objectId;
-
-  callback(mongoObject);
-};
-
-/**
- * @return {number} the length of the data
- */
-Chunk.prototype.length = function() {
-  return this.data.length();
-};
-
-/**
- * The position of the read/write head
- * @name position
- * @lends Chunk#
- * @field
- */
-Object.defineProperty(Chunk.prototype, 'position', {
-  enumerable: true,
-  get: function() {
-    return this.internalPosition;
-  },
-  set: function(value) {
-    this.internalPosition = value;
-  }
-});
-
-/**
- * The default chunk size
- * @constant
- */
-Chunk.DEFAULT_CHUNK_SIZE = 1024 * 255;
-
-module.exports = Chunk;
diff --git a/node_modules/mongodb/lib/gridfs/grid_store.js b/node_modules/mongodb/lib/gridfs/grid_store.js
deleted file mode 100644
index a7c543a..0000000
--- a/node_modules/mongodb/lib/gridfs/grid_store.js
+++ /dev/null
@@ -1,1921 +0,0 @@
-'use strict';
-
-/**
- * @fileOverview GridFS is a tool for MongoDB to store files to the database.
- * Because of the restrictions of the object size the database can hold, a
- * facility to split a file into several chunks is needed. The {@link GridStore}
- * class offers a simplified api to interact with files while managing the
- * chunks of split files behind the scenes. More information about GridFS can be
- * found <a href="http://www.mongodb.org/display/DOCS/GridFS">here</a>.
- *
- * @example
- * const MongoClient = require('mongodb').MongoClient;
- * const GridStore = require('mongodb').GridStore;
- * const ObjectID = require('mongodb').ObjectID;
- * const test = require('assert');
- * // Connection url
- * const url = 'mongodb://localhost:27017';
- * // Database Name
- * const dbName = 'test';
- * // Connect using MongoClient
- * MongoClient.connect(url, function(err, client) {
- *   const db = client.db(dbName);
- *   const gridStore = new GridStore(db, null, "w");
- *   gridStore.open(function(err, gridStore) {
- *     gridStore.write("hello world!", function(err, gridStore) {
- *       gridStore.close(function(err, result) {
- *         // Let's read the file using object Id
- *         GridStore.read(db, result._id, function(err, data) {
- *           test.equal('hello world!', data);
- *           client.close();
- *           test.done();
- *         });
- *       });
- *     });
- *   });
- * });
- */
-const Chunk = require('./chunk');
-const ObjectID = require('../core').BSON.ObjectID;
-const ReadPreference = require('../core').ReadPreference;
-const Buffer = require('safe-buffer').Buffer;
-const fs = require('fs');
-const f = require('util').format;
-const util = require('util');
-const MongoError = require('../core').MongoError;
-const inherits = util.inherits;
-const Duplex = require('stream').Duplex;
-const shallowClone = require('../utils').shallowClone;
-const executeLegacyOperation = require('../utils').executeLegacyOperation;
-const deprecate = require('util').deprecate;
-
-var REFERENCE_BY_FILENAME = 0,
-  REFERENCE_BY_ID = 1;
-
-const deprecationFn = deprecate(() => {},
-'GridStore is deprecated, and will be removed in a future version. Please use GridFSBucket instead');
-
-/**
- * Namespace provided by the core module
- * @external Duplex
- */
-
-/**
- * Create a new GridStore instance
- *
- * Modes
- *  - **"r"** - read only. This is the default mode.
- *  - **"w"** - write in truncate mode. Existing data will be overwritten.
- *
- * @class
- * @param {Db} db A database instance to interact with.
- * @param {object} [id] optional unique id for this file
- * @param {string} [filename] optional filename for this file, no unique constrain on the field
- * @param {string} mode set the mode for this file.
- * @param {object} [options] Optional settings.
- * @param {(number|string)} [options.w] The write concern.
- * @param {number} [options.wtimeout] The write concern timeout.
- * @param {boolean} [options.j=false] Specify a journal write concern.
- * @param {boolean} [options.fsync=false] Specify a file sync write concern.
- * @param {string} [options.root] Root collection to use. Defaults to **{GridStore.DEFAULT_ROOT_COLLECTION}**.
- * @param {string} [options.content_type] MIME type of the file. Defaults to **{GridStore.DEFAULT_CONTENT_TYPE}**.
- * @param {number} [options.chunk_size=261120] Size for the chunk. Defaults to **{Chunk.DEFAULT_CHUNK_SIZE}**.
- * @param {object} [options.metadata] Arbitrary data the user wants to store.
- * @param {object} [options.promiseLibrary] A Promise library class the application wishes to use such as Bluebird, must be ES6 compatible
- * @param {(ReadPreference|string)} [options.readPreference] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
- * @property {number} chunkSize Get the gridstore chunk size.
- * @property {number} md5 The md5 checksum for this file.
- * @property {number} chunkNumber The current chunk number the gridstore has materialized into memory
- * @return {GridStore} a GridStore instance.
- * @deprecated Use GridFSBucket API instead
- */
-var GridStore = function GridStore(db, id, filename, mode, options) {
-  deprecationFn();
-  if (!(this instanceof GridStore)) return new GridStore(db, id, filename, mode, options);
-  this.db = db;
-
-  // Handle options
-  if (typeof options === 'undefined') options = {};
-  // Handle mode
-  if (typeof mode === 'undefined') {
-    mode = filename;
-    filename = undefined;
-  } else if (typeof mode === 'object') {
-    options = mode;
-    mode = filename;
-    filename = undefined;
-  }
-
-  if (id && id._bsontype === 'ObjectID') {
-    this.referenceBy = REFERENCE_BY_ID;
-    this.fileId = id;
-    this.filename = filename;
-  } else if (typeof filename === 'undefined') {
-    this.referenceBy = REFERENCE_BY_FILENAME;
-    this.filename = id;
-    if (mode.indexOf('w') != null) {
-      this.fileId = new ObjectID();
-    }
-  } else {
-    this.referenceBy = REFERENCE_BY_ID;
-    this.fileId = id;
-    this.filename = filename;
-  }
-
-  // Set up the rest
-  this.mode = mode == null ? 'r' : mode;
-  this.options = options || {};
-
-  // Opened
-  this.isOpen = false;
-
-  // Set the root if overridden
-  this.root =
-    this.options['root'] == null ? GridStore.DEFAULT_ROOT_COLLECTION : this.options['root'];
-  this.position = 0;
-  this.readPreference =
-    this.options.readPreference || db.options.readPreference || ReadPreference.primary;
-  this.writeConcern = _getWriteConcern(db, this.options);
-  // Set default chunk size
-  this.internalChunkSize =
-    this.options['chunkSize'] == null ? Chunk.DEFAULT_CHUNK_SIZE : this.options['chunkSize'];
-
-  // Get the promiseLibrary
-  var promiseLibrary = this.options.promiseLibrary || Promise;
-
-  // Set the promiseLibrary
-  this.promiseLibrary = promiseLibrary;
-
-  Object.defineProperty(this, 'chunkSize', {
-    enumerable: true,
-    get: function() {
-      return this.internalChunkSize;
-    },
-    set: function(value) {
-      if (!(this.mode[0] === 'w' && this.position === 0 && this.uploadDate == null)) {
-        // eslint-disable-next-line no-self-assign
-        this.internalChunkSize = this.internalChunkSize;
-      } else {
-        this.internalChunkSize = value;
-      }
-    }
-  });
-
-  Object.defineProperty(this, 'md5', {
-    enumerable: true,
-    get: function() {
-      return this.internalMd5;
-    }
-  });
-
-  Object.defineProperty(this, 'chunkNumber', {
-    enumerable: true,
-    get: function() {
-      return this.currentChunk && this.currentChunk.chunkNumber
-        ? this.currentChunk.chunkNumber
-        : null;
-    }
-  });
-};
-
-/**
- * The callback format for the Gridstore.open method
- * @callback GridStore~openCallback
- * @param {MongoError} error An error instance representing the error during the execution.
- * @param {GridStore} gridStore The GridStore instance if the open method was successful.
- */
-
-/**
- * Opens the file from the database and initialize this object. Also creates a
- * new one if file does not exist.
- *
- * @method
- * @param {object} [options] Optional settings
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~openCallback} [callback] this will be called after executing this method
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.open = function(options, callback) {
-  if (typeof options === 'function') (callback = options), (options = {});
-  options = options || {};
-
-  if (this.mode !== 'w' && this.mode !== 'w+' && this.mode !== 'r') {
-    throw MongoError.create({ message: 'Illegal mode ' + this.mode, driver: true });
-  }
-
-  return executeLegacyOperation(this.db.s.topology, open, [this, options, callback], {
-    skipSessions: true
-  });
-};
-
-var open = function(self, options, callback) {
-  // Get the write concern
-  var writeConcern = _getWriteConcern(self.db, self.options);
-
-  // If we are writing we need to ensure we have the right indexes for md5's
-  if (self.mode === 'w' || self.mode === 'w+') {
-    // Get files collection
-    var collection = self.collection();
-    // Put index on filename
-    collection.ensureIndex([['filename', 1]], writeConcern, function() {
-      // Get chunk collection
-      var chunkCollection = self.chunkCollection();
-      // Make an unique index for compatibility with mongo-cxx-driver:legacy
-      var chunkIndexOptions = shallowClone(writeConcern);
-      chunkIndexOptions.unique = true;
-      // Ensure index on chunk collection
-      chunkCollection.ensureIndex(
-        [
-          ['files_id', 1],
-          ['n', 1]
-        ],
-        chunkIndexOptions,
-        function() {
-          // Open the connection
-          _open(self, writeConcern, function(err, r) {
-            if (err) return callback(err);
-            self.isOpen = true;
-            callback(err, r);
-          });
-        }
-      );
-    });
-  } else {
-    // Open the gridstore
-    _open(self, writeConcern, function(err, r) {
-      if (err) return callback(err);
-      self.isOpen = true;
-      callback(err, r);
-    });
-  }
-};
-
-/**
- * Verify if the file is at EOF.
- *
- * @method
- * @return {boolean} true if the read/write head is at the end of this file.
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.eof = function() {
-  return this.position === this.length ? true : false;
-};
-
-/**
- * The callback result format.
- * @callback GridStore~resultCallback
- * @param {object} [options] Optional settings
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {MongoError} error An error instance representing the error during the execution.
- * @param {object} result The result from the callback.
- */
-
-/**
- * Retrieves a single character from this file.
- *
- * @method
- * @param {GridStore~resultCallback} [callback] this gets called after this method is executed. Passes null to the first parameter and the character read to the second or null to the second if the read/write head is at the end of the file.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.getc = function(options, callback) {
-  if (typeof options === 'function') (callback = options), (options = {});
-  options = options || {};
-
-  return executeLegacyOperation(this.db.s.topology, getc, [this, options, callback], {
-    skipSessions: true
-  });
-};
-
-var getc = function(self, options, callback) {
-  if (self.eof()) {
-    callback(null, null);
-  } else if (self.currentChunk.eof()) {
-    nthChunk(self, self.currentChunk.chunkNumber + 1, function(err, chunk) {
-      self.currentChunk = chunk;
-      self.position = self.position + 1;
-      callback(err, self.currentChunk.getc());
-    });
-  } else {
-    self.position = self.position + 1;
-    callback(null, self.currentChunk.getc());
-  }
-};
-
-/**
- * Writes a string to the file with a newline character appended at the end if
- * the given string does not have one.
- *
- * @method
- * @param {string} string the string to write.
- * @param {object} [options] Optional settings
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~resultCallback} [callback] this will be called after executing this method. The first parameter will contain null and the second one will contain a reference to this object.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.puts = function(string, options, callback) {
-  if (typeof options === 'function') (callback = options), (options = {});
-  options = options || {};
-
-  var finalString = string.match(/\n$/) == null ? string + '\n' : string;
-  return executeLegacyOperation(
-    this.db.s.topology,
-    this.write.bind(this),
-    [finalString, options, callback],
-    { skipSessions: true }
-  );
-};
-
-/**
- * Return a modified Readable stream including a possible transform method.
- *
- * @method
- * @return {GridStoreStream}
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.stream = function() {
-  return new GridStoreStream(this);
-};
-
-/**
- * Writes some data. This method will work properly only if initialized with mode "w" or "w+".
- *
- * @method
- * @param {(string|Buffer)} data the data to write.
- * @param {boolean} [close] closes this file after writing if set to true.
- * @param {object} [options] Optional settings
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~resultCallback} [callback] this will be called after executing this method. The first parameter will contain null and the second one will contain a reference to this object.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.write = function write(data, close, options, callback) {
-  if (typeof options === 'function') (callback = options), (options = {});
-  options = options || {};
-
-  return executeLegacyOperation(
-    this.db.s.topology,
-    _writeNormal,
-    [this, data, close, options, callback],
-    { skipSessions: true }
-  );
-};
-
-/**
- * Handles the destroy part of a stream
- *
- * @method
- * @result {null}
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.destroy = function destroy() {
-  // close and do not emit any more events. queued data is not sent.
-  if (!this.writable) return;
-  this.readable = false;
-  if (this.writable) {
-    this.writable = false;
-    this._q.length = 0;
-    this.emit('close');
-  }
-};
-
-/**
- * Stores a file from the file system to the GridFS database.
- *
- * @method
- * @param {(string|Buffer|FileHandle)} file the file to store.
- * @param {object} [options] Optional settings
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~resultCallback} [callback] this will be called after executing this method. The first parameter will contain null and the second one will contain a reference to this object.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.writeFile = function(file, options, callback) {
-  if (typeof options === 'function') (callback = options), (options = {});
-  options = options || {};
-
-  return executeLegacyOperation(this.db.s.topology, writeFile, [this, file, options, callback], {
-    skipSessions: true
-  });
-};
-
-var writeFile = function(self, file, options, callback) {
-  if (typeof file === 'string') {
-    fs.open(file, 'r', function(err, fd) {
-      if (err) return callback(err);
-      self.writeFile(fd, callback);
-    });
-    return;
-  }
-
-  self.open(function(err, self) {
-    if (err) return callback(err, self);
-
-    fs.fstat(file, function(err, stats) {
-      if (err) return callback(err, self);
-
-      var offset = 0;
-      var index = 0;
-
-      // Write a chunk
-      var writeChunk = function() {
-        // Allocate the buffer
-        var _buffer = Buffer.alloc(self.chunkSize);
-        // Read the file
-        fs.read(file, _buffer, 0, _buffer.length, offset, function(err, bytesRead, data) {
-          if (err) return callback(err, self);
-
-          offset = offset + bytesRead;
-
-          // Create a new chunk for the data
-          var chunk = new Chunk(self, { n: index++ }, self.writeConcern);
-          chunk.write(data.slice(0, bytesRead), function(err, chunk) {
-            if (err) return callback(err, self);
-
-            chunk.save({}, function(err) {
-              if (err) return callback(err, self);
-
-              self.position = self.position + bytesRead;
-
-              // Point to current chunk
-              self.currentChunk = chunk;
-
-              if (offset >= stats.size) {
-                fs.close(file, function(err) {
-                  if (err) return callback(err);
-
-                  self.close(function(err) {
-                    if (err) return callback(err, self);
-                    return callback(null, self);
-                  });
-                });
-              } else {
-                return process.nextTick(writeChunk);
-              }
-            });
-          });
-        });
-      };
-
-      // Process the first write
-      process.nextTick(writeChunk);
-    });
-  });
-};
-
-/**
- * Saves this file to the database. This will overwrite the old entry if it
- * already exists. This will work properly only if mode was initialized to
- * "w" or "w+".
- *
- * @method
- * @param {object} [options] Optional settings
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~resultCallback} [callback] this will be called after executing this method. The first parameter will contain null and the second one will contain a reference to this object.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.close = function(options, callback) {
-  if (typeof options === 'function') (callback = options), (options = {});
-  options = options || {};
-
-  return executeLegacyOperation(this.db.s.topology, close, [this, options, callback], {
-    skipSessions: true
-  });
-};
-
-var close = function(self, options, callback) {
-  if (self.mode[0] === 'w') {
-    // Set up options
-    options = Object.assign({}, self.writeConcern, options);
-
-    if (self.currentChunk != null && self.currentChunk.position > 0) {
-      self.currentChunk.save({}, function(err) {
-        if (err && typeof callback === 'function') return callback(err);
-
-        self.collection(function(err, files) {
-          if (err && typeof callback === 'function') return callback(err);
-
-          // Build the mongo object
-          if (self.uploadDate != null) {
-            buildMongoObject(self, function(err, mongoObject) {
-              if (err) {
-                if (typeof callback === 'function') return callback(err);
-                else throw err;
-              }
-
-              files.save(mongoObject, options, function(err) {
-                if (typeof callback === 'function') callback(err, mongoObject);
-              });
-            });
-          } else {
-            self.uploadDate = new Date();
-            buildMongoObject(self, function(err, mongoObject) {
-              if (err) {
-                if (typeof callback === 'function') return callback(err);
-                else throw err;
-              }
-
-              files.save(mongoObject, options, function(err) {
-                if (typeof callback === 'function') callback(err, mongoObject);
-              });
-            });
-          }
-        });
-      });
-    } else {
-      self.collection(function(err, files) {
-        if (err && typeof callback === 'function') return callback(err);
-
-        self.uploadDate = new Date();
-        buildMongoObject(self, function(err, mongoObject) {
-          if (err) {
-            if (typeof callback === 'function') return callback(err);
-            else throw err;
-          }
-
-          files.save(mongoObject, options, function(err) {
-            if (typeof callback === 'function') callback(err, mongoObject);
-          });
-        });
-      });
-    }
-  } else if (self.mode[0] === 'r') {
-    if (typeof callback === 'function') callback(null, null);
-  } else {
-    if (typeof callback === 'function')
-      callback(MongoError.create({ message: f('Illegal mode %s', self.mode), driver: true }));
-  }
-};
-
-/**
- * The collection callback format.
- * @callback GridStore~collectionCallback
- * @param {MongoError} error An error instance representing the error during the execution.
- * @param {Collection} collection The collection from the command execution.
- */
-
-/**
- * Retrieve this file's chunks collection.
- *
- * @method
- * @param {GridStore~collectionCallback} callback the command callback.
- * @return {Collection}
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.chunkCollection = function(callback) {
-  if (typeof callback === 'function') return this.db.collection(this.root + '.chunks', callback);
-  return this.db.collection(this.root + '.chunks');
-};
-
-/**
- * Deletes all the chunks of this file in the database.
- *
- * @method
- * @param {object} [options] Optional settings
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~resultCallback} [callback] the command callback.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.unlink = function(options, callback) {
-  if (typeof options === 'function') (callback = options), (options = {});
-  options = options || {};
-
-  return executeLegacyOperation(this.db.s.topology, unlink, [this, options, callback], {
-    skipSessions: true
-  });
-};
-
-var unlink = function(self, options, callback) {
-  deleteChunks(self, function(err) {
-    if (err !== null) {
-      err.message = 'at deleteChunks: ' + err.message;
-      return callback(err);
-    }
-
-    self.collection(function(err, collection) {
-      if (err !== null) {
-        err.message = 'at collection: ' + err.message;
-        return callback(err);
-      }
-
-      collection.remove({ _id: self.fileId }, self.writeConcern, function(err) {
-        callback(err, self);
-      });
-    });
-  });
-};
-
-/**
- * Retrieves the file collection associated with this object.
- *
- * @method
- * @param {GridStore~collectionCallback} callback the command callback.
- * @return {Collection}
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.collection = function(callback) {
-  if (typeof callback === 'function') this.db.collection(this.root + '.files', callback);
-  return this.db.collection(this.root + '.files');
-};
-
-/**
- * The readlines callback format.
- * @callback GridStore~readlinesCallback
- * @param {MongoError} error An error instance representing the error during the execution.
- * @param {string[]} strings The array of strings returned.
- */
-
-/**
- * Read the entire file as a list of strings splitting by the provided separator.
- *
- * @method
- * @param {string} [separator] The character to be recognized as the newline separator.
- * @param {object} [options] Optional settings
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~readlinesCallback} [callback] the command callback.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.readlines = function(separator, options, callback) {
-  var args = Array.prototype.slice.call(arguments, 0);
-  callback = typeof args[args.length - 1] === 'function' ? args.pop() : undefined;
-  separator = args.length ? args.shift() : '\n';
-  separator = separator || '\n';
-  options = args.length ? args.shift() : {};
-
-  return executeLegacyOperation(
-    this.db.s.topology,
-    readlines,
-    [this, separator, options, callback],
-    { skipSessions: true }
-  );
-};
-
-var readlines = function(self, separator, options, callback) {
-  self.read(function(err, data) {
-    if (err) return callback(err);
-
-    var items = data.toString().split(separator);
-    items = items.length > 0 ? items.splice(0, items.length - 1) : [];
-    for (var i = 0; i < items.length; i++) {
-      items[i] = items[i] + separator;
-    }
-
-    callback(null, items);
-  });
-};
-
-/**
- * Deletes all the chunks of this file in the database if mode was set to "w" or
- * "w+" and resets the read/write head to the initial position.
- *
- * @method
- * @param {object} [options] Optional settings
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~resultCallback} [callback] this will be called after executing this method. The first parameter will contain null and the second one will contain a reference to this object.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.rewind = function(options, callback) {
-  if (typeof options === 'function') (callback = options), (options = {});
-  options = options || {};
-
-  return executeLegacyOperation(this.db.s.topology, rewind, [this, options, callback], {
-    skipSessions: true
-  });
-};
-
-var rewind = function(self, options, callback) {
-  if (self.currentChunk.chunkNumber !== 0) {
-    if (self.mode[0] === 'w') {
-      deleteChunks(self, function(err) {
-        if (err) return callback(err);
-        self.currentChunk = new Chunk(self, { n: 0 }, self.writeConcern);
-        self.position = 0;
-        callback(null, self);
-      });
-    } else {
-      self.currentChunk(0, function(err, chunk) {
-        if (err) return callback(err);
-        self.currentChunk = chunk;
-        self.currentChunk.rewind();
-        self.position = 0;
-        callback(null, self);
-      });
-    }
-  } else {
-    self.currentChunk.rewind();
-    self.position = 0;
-    callback(null, self);
-  }
-};
-
-/**
- * The read callback format.
- * @callback GridStore~readCallback
- * @param {MongoError} error An error instance representing the error during the execution.
- * @param {Buffer} data The data read from the GridStore object
- */
-
-/**
- * Retrieves the contents of this file and advances the read/write head. Works with Buffers only.
- *
- * There are 3 signatures for this method:
- *
- * (callback)
- * (length, callback)
- * (length, buffer, callback)
- *
- * @method
- * @param {number} [length] the number of characters to read. Reads all the characters from the read/write head to the EOF if not specified.
- * @param {(string|Buffer)} [buffer] a string to hold temporary data. This is used for storing the string data read so far when recursively calling this method.
- * @param {object} [options] Optional settings
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~readCallback} [callback] the command callback.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.read = function(length, buffer, options, callback) {
-  var args = Array.prototype.slice.call(arguments, 0);
-  callback = typeof args[args.length - 1] === 'function' ? args.pop() : undefined;
-  length = args.length ? args.shift() : null;
-  buffer = args.length ? args.shift() : null;
-  options = args.length ? args.shift() : {};
-
-  return executeLegacyOperation(
-    this.db.s.topology,
-    read,
-    [this, length, buffer, options, callback],
-    { skipSessions: true }
-  );
-};
-
-var read = function(self, length, buffer, options, callback) {
-  // The data is a c-terminated string and thus the length - 1
-  var finalLength = length == null ? self.length - self.position : length;
-  var finalBuffer = buffer == null ? Buffer.alloc(finalLength) : buffer;
-  // Add a index to buffer to keep track of writing position or apply current index
-  finalBuffer._index = buffer != null && buffer._index != null ? buffer._index : 0;
-
-  if (self.currentChunk.length() - self.currentChunk.position + finalBuffer._index >= finalLength) {
-    var slice = self.currentChunk.readSlice(finalLength - finalBuffer._index);
-    // Copy content to final buffer
-    slice.copy(finalBuffer, finalBuffer._index);
-    // Update internal position
-    self.position = self.position + finalBuffer.length;
-    // Check if we don't have a file at all
-    if (finalLength === 0 && finalBuffer.length === 0)
-      return callback(MongoError.create({ message: 'File does not exist', driver: true }), null);
-    // Else return data
-    return callback(null, finalBuffer);
-  }
-
-  // Read the next chunk
-  slice = self.currentChunk.readSlice(self.currentChunk.length() - self.currentChunk.position);
-  // Copy content to final buffer
-  slice.copy(finalBuffer, finalBuffer._index);
-  // Update index position
-  finalBuffer._index += slice.length;
-
-  // Load next chunk and read more
-  nthChunk(self, self.currentChunk.chunkNumber + 1, function(err, chunk) {
-    if (err) return callback(err);
-
-    if (chunk.length() > 0) {
-      self.currentChunk = chunk;
-      self.read(length, finalBuffer, callback);
-    } else {
-      if (finalBuffer._index > 0) {
-        callback(null, finalBuffer);
-      } else {
-        callback(
-          MongoError.create({
-            message: 'no chunks found for file, possibly corrupt',
-            driver: true
-          }),
-          null
-        );
-      }
-    }
-  });
-};
-
-/**
- * The tell callback format.
- * @callback GridStore~tellCallback
- * @param {MongoError} error An error instance representing the error during the execution.
- * @param {number} position The current read position in the GridStore.
- */
-
-/**
- * Retrieves the position of the read/write head of this file.
- *
- * @method
- * @param {number} [length] the number of characters to read. Reads all the characters from the read/write head to the EOF if not specified.
- * @param {(string|Buffer)} [buffer] a string to hold temporary data. This is used for storing the string data read so far when recursively calling this method.
- * @param {object} [options] Optional settings
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~tellCallback} [callback] the command callback.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.tell = function(callback) {
-  var self = this;
-  // We provided a callback leg
-  if (typeof callback === 'function') return callback(null, this.position);
-  // Return promise
-  return new self.promiseLibrary(function(resolve) {
-    resolve(self.position);
-  });
-};
-
-/**
- * The tell callback format.
- * @callback GridStore~gridStoreCallback
- * @param {MongoError} error An error instance representing the error during the execution.
- * @param {GridStore} gridStore The gridStore.
- */
-
-/**
- * Moves the read/write head to a new location.
- *
- * There are 3 signatures for this method
- *
- * Seek Location Modes
- *  - **GridStore.IO_SEEK_SET**, **(default)** set the position from the start of the file.
- *  - **GridStore.IO_SEEK_CUR**, set the position from the current position in the file.
- *  - **GridStore.IO_SEEK_END**, set the position from the end of the file.
- *
- * @method
- * @param {number} [position] the position to seek to
- * @param {number} [seekLocation] seek mode. Use one of the Seek Location modes.
- * @param {object} [options] Optional settings
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~gridStoreCallback} [callback] the command callback.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.prototype.seek = function(position, seekLocation, options, callback) {
-  var args = Array.prototype.slice.call(arguments, 1);
-  callback = typeof args[args.length - 1] === 'function' ? args.pop() : undefined;
-  seekLocation = args.length ? args.shift() : null;
-  options = args.length ? args.shift() : {};
-
-  return executeLegacyOperation(
-    this.db.s.topology,
-    seek,
-    [this, position, seekLocation, options, callback],
-    { skipSessions: true }
-  );
-};
-
-var seek = function(self, position, seekLocation, options, callback) {
-  // Seek only supports read mode
-  if (self.mode !== 'r') {
-    return callback(
-      MongoError.create({ message: 'seek is only supported for mode r', driver: true })
-    );
-  }
-
-  var seekLocationFinal = seekLocation == null ? GridStore.IO_SEEK_SET : seekLocation;
-  var finalPosition = position;
-  var targetPosition = 0;
-
-  // Calculate the position
-  if (seekLocationFinal === GridStore.IO_SEEK_CUR) {
-    targetPosition = self.position + finalPosition;
-  } else if (seekLocationFinal === GridStore.IO_SEEK_END) {
-    targetPosition = self.length + finalPosition;
-  } else {
-    targetPosition = finalPosition;
-  }
-
-  // Get the chunk
-  var newChunkNumber = Math.floor(targetPosition / self.chunkSize);
-  var seekChunk = function() {
-    nthChunk(self, newChunkNumber, function(err, chunk) {
-      if (err) return callback(err, null);
-      if (chunk == null) return callback(new Error('no chunk found'));
-
-      // Set the current chunk
-      self.currentChunk = chunk;
-      self.position = targetPosition;
-      self.currentChunk.position = self.position % self.chunkSize;
-      callback(err, self);
-    });
-  };
-
-  seekChunk();
-};
-
-/**
- * @ignore
- */
-var _open = function(self, options, callback) {
-  var collection = self.collection();
-  // Create the query
-  var query =
-    self.referenceBy === REFERENCE_BY_ID ? { _id: self.fileId } : { filename: self.filename };
-  query = null == self.fileId && self.filename == null ? null : query;
-  options.readPreference = self.readPreference;
-
-  // Fetch the chunks
-  if (query != null) {
-    collection.findOne(query, options, function(err, doc) {
-      if (err) {
-        return error(err);
-      }
-
-      // Check if the collection for the files exists otherwise prepare the new one
-      if (doc != null) {
-        self.fileId = doc._id;
-        // Prefer a new filename over the existing one if this is a write
-        self.filename =
-          self.mode === 'r' || self.filename === undefined ? doc.filename : self.filename;
-        self.contentType = doc.contentType;
-        self.internalChunkSize = doc.chunkSize;
-        self.uploadDate = doc.uploadDate;
-        self.aliases = doc.aliases;
-        self.length = doc.length;
-        self.metadata = doc.metadata;
-        self.internalMd5 = doc.md5;
-      } else if (self.mode !== 'r') {
-        self.fileId = self.fileId == null ? new ObjectID() : self.fileId;
-        self.contentType = GridStore.DEFAULT_CONTENT_TYPE;
-        self.internalChunkSize =
-          self.internalChunkSize == null ? Chunk.DEFAULT_CHUNK_SIZE : self.internalChunkSize;
-        self.length = 0;
-      } else {
-        self.length = 0;
-        var txtId = self.fileId._bsontype === 'ObjectID' ? self.fileId.toHexString() : self.fileId;
-        return error(
-          MongoError.create({
-            message: f(
-              'file with id %s not opened for writing',
-              self.referenceBy === REFERENCE_BY_ID ? txtId : self.filename
-            ),
-            driver: true
-          }),
-          self
-        );
-      }
-
-      // Process the mode of the object
-      if (self.mode === 'r') {
-        nthChunk(self, 0, options, function(err, chunk) {
-          if (err) return error(err);
-          self.currentChunk = chunk;
-          self.position = 0;
-          callback(null, self);
-        });
-      } else if (self.mode === 'w' && doc) {
-        // Delete any existing chunks
-        deleteChunks(self, options, function(err) {
-          if (err) return error(err);
-          self.currentChunk = new Chunk(self, { n: 0 }, self.writeConcern);
-          self.contentType =
-            self.options['content_type'] == null ? self.contentType : self.options['content_type'];
-          self.internalChunkSize =
-            self.options['chunk_size'] == null
-              ? self.internalChunkSize
-              : self.options['chunk_size'];
-          self.metadata =
-            self.options['metadata'] == null ? self.metadata : self.options['metadata'];
-          self.aliases = self.options['aliases'] == null ? self.aliases : self.options['aliases'];
-          self.position = 0;
-          callback(null, self);
-        });
-      } else if (self.mode === 'w') {
-        self.currentChunk = new Chunk(self, { n: 0 }, self.writeConcern);
-        self.contentType =
-          self.options['content_type'] == null ? self.contentType : self.options['content_type'];
-        self.internalChunkSize =
-          self.options['chunk_size'] == null ? self.internalChunkSize : self.options['chunk_size'];
-        self.metadata = self.options['metadata'] == null ? self.metadata : self.options['metadata'];
-        self.aliases = self.options['aliases'] == null ? self.aliases : self.options['aliases'];
-        self.position = 0;
-        callback(null, self);
-      } else if (self.mode === 'w+') {
-        nthChunk(self, lastChunkNumber(self), options, function(err, chunk) {
-          if (err) return error(err);
-          // Set the current chunk
-          self.currentChunk = chunk == null ? new Chunk(self, { n: 0 }, self.writeConcern) : chunk;
-          self.currentChunk.position = self.currentChunk.data.length();
-          self.metadata =
-            self.options['metadata'] == null ? self.metadata : self.options['metadata'];
-          self.aliases = self.options['aliases'] == null ? self.aliases : self.options['aliases'];
-          self.position = self.length;
-          callback(null, self);
-        });
-      }
-    });
-  } else {
-    // Write only mode
-    self.fileId = null == self.fileId ? new ObjectID() : self.fileId;
-    self.contentType = GridStore.DEFAULT_CONTENT_TYPE;
-    self.internalChunkSize =
-      self.internalChunkSize == null ? Chunk.DEFAULT_CHUNK_SIZE : self.internalChunkSize;
-    self.length = 0;
-
-    // No file exists set up write mode
-    if (self.mode === 'w') {
-      // Delete any existing chunks
-      deleteChunks(self, options, function(err) {
-        if (err) return error(err);
-        self.currentChunk = new Chunk(self, { n: 0 }, self.writeConcern);
-        self.contentType =
-          self.options['content_type'] == null ? self.contentType : self.options['content_type'];
-        self.internalChunkSize =
-          self.options['chunk_size'] == null ? self.internalChunkSize : self.options['chunk_size'];
-        self.metadata = self.options['metadata'] == null ? self.metadata : self.options['metadata'];
-        self.aliases = self.options['aliases'] == null ? self.aliases : self.options['aliases'];
-        self.position = 0;
-        callback(null, self);
-      });
-    } else if (self.mode === 'w+') {
-      nthChunk(self, lastChunkNumber(self), options, function(err, chunk) {
-        if (err) return error(err);
-        // Set the current chunk
-        self.currentChunk = chunk == null ? new Chunk(self, { n: 0 }, self.writeConcern) : chunk;
-        self.currentChunk.position = self.currentChunk.data.length();
-        self.metadata = self.options['metadata'] == null ? self.metadata : self.options['metadata'];
-        self.aliases = self.options['aliases'] == null ? self.aliases : self.options['aliases'];
-        self.position = self.length;
-        callback(null, self);
-      });
-    }
-  }
-
-  // only pass error to callback once
-  function error(err) {
-    if (error.err) return;
-    callback((error.err = err));
-  }
-};
-
-/**
- * @ignore
- */
-var writeBuffer = function(self, buffer, close, callback) {
-  if (typeof close === 'function') {
-    callback = close;
-    close = null;
-  }
-  var finalClose = typeof close === 'boolean' ? close : false;
-
-  if (self.mode !== 'w') {
-    callback(
-      MongoError.create({
-        message: f(
-          'file with id %s not opened for writing',
-          self.referenceBy === REFERENCE_BY_ID ? self.referenceBy : self.filename
-        ),
-        driver: true
-      }),
-      null
-    );
-  } else {
-    if (self.currentChunk.position + buffer.length >= self.chunkSize) {
-      // Write out the current Chunk and then keep writing until we have less data left than a chunkSize left
-      // to a new chunk (recursively)
-      var previousChunkNumber = self.currentChunk.chunkNumber;
-      var leftOverDataSize = self.chunkSize - self.currentChunk.position;
-      var firstChunkData = buffer.slice(0, leftOverDataSize);
-      var leftOverData = buffer.slice(leftOverDataSize);
-      // A list of chunks to write out
-      var chunksToWrite = [self.currentChunk.write(firstChunkData)];
-      // If we have more data left than the chunk size let's keep writing new chunks
-      while (leftOverData.length >= self.chunkSize) {
-        // Create a new chunk and write to it
-        var newChunk = new Chunk(self, { n: previousChunkNumber + 1 }, self.writeConcern);
-        firstChunkData = leftOverData.slice(0, self.chunkSize);
-        leftOverData = leftOverData.slice(self.chunkSize);
-        // Update chunk number
-        previousChunkNumber = previousChunkNumber + 1;
-        // Write data
-        newChunk.write(firstChunkData);
-        // Push chunk to save list
-        chunksToWrite.push(newChunk);
-      }
-
-      // Set current chunk with remaining data
-      self.currentChunk = new Chunk(self, { n: previousChunkNumber + 1 }, self.writeConcern);
-      // If we have left over data write it
-      if (leftOverData.length > 0) self.currentChunk.write(leftOverData);
-
-      // Update the position for the gridstore
-      self.position = self.position + buffer.length;
-      // Total number of chunks to write
-      var numberOfChunksToWrite = chunksToWrite.length;
-
-      for (var i = 0; i < chunksToWrite.length; i++) {
-        chunksToWrite[i].save({}, function(err) {
-          if (err) return callback(err);
-
-          numberOfChunksToWrite = numberOfChunksToWrite - 1;
-
-          if (numberOfChunksToWrite <= 0) {
-            // We care closing the file before returning
-            if (finalClose) {
-              return self.close(function(err) {
-                callback(err, self);
-              });
-            }
-
-            // Return normally
-            return callback(null, self);
-          }
-        });
-      }
-    } else {
-      // Update the position for the gridstore
-      self.position = self.position + buffer.length;
-      // We have less data than the chunk size just write it and callback
-      self.currentChunk.write(buffer);
-      // We care closing the file before returning
-      if (finalClose) {
-        return self.close(function(err) {
-          callback(err, self);
-        });
-      }
-      // Return normally
-      return callback(null, self);
-    }
-  }
-};
-
-/**
- * Creates a mongoDB object representation of this object.
- *
- *        <pre><code>
- *        {
- *          '_id' : , // {number} id for this file
- *          'filename' : , // {string} name for this file
- *          'contentType' : , // {string} mime type for this file
- *          'length' : , // {number} size of this file?
- *          'chunksize' : , // {number} chunk size used by this file
- *          'uploadDate' : , // {Date}
- *          'aliases' : , // {array of string}
- *          'metadata' : , // {string}
- *        }
- *        </code></pre>
- *
- * @ignore
- */
-var buildMongoObject = function(self, callback) {
-  // Calcuate the length
-  var mongoObject = {
-    _id: self.fileId,
-    filename: self.filename,
-    contentType: self.contentType,
-    length: self.position ? self.position : 0,
-    chunkSize: self.chunkSize,
-    uploadDate: self.uploadDate,
-    aliases: self.aliases,
-    metadata: self.metadata
-  };
-
-  var md5Command = { filemd5: self.fileId, root: self.root };
-  self.db.command(md5Command, function(err, results) {
-    if (err) return callback(err);
-
-    mongoObject.md5 = results.md5;
-    callback(null, mongoObject);
-  });
-};
-
-/**
- * Gets the nth chunk of this file.
- * @ignore
- */
-var nthChunk = function(self, chunkNumber, options, callback) {
-  if (typeof options === 'function') {
-    callback = options;
-    options = {};
-  }
-
-  options = options || self.writeConcern;
-  options.readPreference = self.readPreference;
-  // Get the nth chunk
-  self
-    .chunkCollection()
-    .findOne({ files_id: self.fileId, n: chunkNumber }, options, function(err, chunk) {
-      if (err) return callback(err);
-
-      var finalChunk = chunk == null ? {} : chunk;
-      callback(null, new Chunk(self, finalChunk, self.writeConcern));
-    });
-};
-
-/**
- * @ignore
- */
-var lastChunkNumber = function(self) {
-  return Math.floor((self.length ? self.length - 1 : 0) / self.chunkSize);
-};
-
-/**
- * Deletes all the chunks of this file in the database.
- *
- * @ignore
- */
-var deleteChunks = function(self, options, callback) {
-  if (typeof options === 'function') {
-    callback = options;
-    options = {};
-  }
-
-  options = options || self.writeConcern;
-
-  if (self.fileId != null) {
-    self.chunkCollection().remove({ files_id: self.fileId }, options, function(err) {
-      if (err) return callback(err, false);
-      callback(null, true);
-    });
-  } else {
-    callback(null, true);
-  }
-};
-
-/**
- * The collection to be used for holding the files and chunks collection.
- *
- * @classconstant DEFAULT_ROOT_COLLECTION
- */
-GridStore.DEFAULT_ROOT_COLLECTION = 'fs';
-
-/**
- * Default file mime type
- *
- * @classconstant DEFAULT_CONTENT_TYPE
- */
-GridStore.DEFAULT_CONTENT_TYPE = 'binary/octet-stream';
-
-/**
- * Seek mode where the given length is absolute.
- *
- * @classconstant IO_SEEK_SET
- */
-GridStore.IO_SEEK_SET = 0;
-
-/**
- * Seek mode where the given length is an offset to the current read/write head.
- *
- * @classconstant IO_SEEK_CUR
- */
-GridStore.IO_SEEK_CUR = 1;
-
-/**
- * Seek mode where the given length is an offset to the end of the file.
- *
- * @classconstant IO_SEEK_END
- */
-GridStore.IO_SEEK_END = 2;
-
-/**
- * Checks if a file exists in the database.
- *
- * @method
- * @static
- * @param {Db} db the database to query.
- * @param {string} name The name of the file to look for.
- * @param {string} [rootCollection] The root collection that holds the files and chunks collection. Defaults to **{GridStore.DEFAULT_ROOT_COLLECTION}**.
- * @param {object} [options] Optional settings.
- * @param {(ReadPreference|string)} [options.readPreference] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
- * @param {object} [options.promiseLibrary] A Promise library class the application wishes to use such as Bluebird, must be ES6 compatible
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~resultCallback} [callback] result from exists.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.exist = function(db, fileIdObject, rootCollection, options, callback) {
-  var args = Array.prototype.slice.call(arguments, 2);
-  callback = typeof args[args.length - 1] === 'function' ? args.pop() : undefined;
-  rootCollection = args.length ? args.shift() : null;
-  options = args.length ? args.shift() : {};
-  options = options || {};
-
-  return executeLegacyOperation(
-    db.s.topology,
-    exists,
-    [db, fileIdObject, rootCollection, options, callback],
-    { skipSessions: true }
-  );
-};
-
-var exists = function(db, fileIdObject, rootCollection, options, callback) {
-  // Establish read preference
-  var readPreference = options.readPreference || ReadPreference.PRIMARY;
-  // Fetch collection
-  var rootCollectionFinal =
-    rootCollection != null ? rootCollection : GridStore.DEFAULT_ROOT_COLLECTION;
-  db.collection(rootCollectionFinal + '.files', function(err, collection) {
-    if (err) return callback(err);
-
-    // Build query
-    var query =
-      typeof fileIdObject === 'string' ||
-      Object.prototype.toString.call(fileIdObject) === '[object RegExp]'
-        ? { filename: fileIdObject }
-        : { _id: fileIdObject }; // Attempt to locate file
-
-    // We have a specific query
-    if (
-      fileIdObject != null &&
-      typeof fileIdObject === 'object' &&
-      Object.prototype.toString.call(fileIdObject) !== '[object RegExp]'
-    ) {
-      query = fileIdObject;
-    }
-
-    // Check if the entry exists
-    collection.findOne(query, { readPreference: readPreference }, function(err, item) {
-      if (err) return callback(err);
-      callback(null, item == null ? false : true);
-    });
-  });
-};
-
-/**
- * Gets the list of files stored in the GridFS.
- *
- * @method
- * @static
- * @param {Db} db the database to query.
- * @param {string} [rootCollection] The root collection that holds the files and chunks collection. Defaults to **{GridStore.DEFAULT_ROOT_COLLECTION}**.
- * @param {object} [options] Optional settings.
- * @param {(ReadPreference|string)} [options.readPreference] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
- * @param {object} [options.promiseLibrary] A Promise library class the application wishes to use such as Bluebird, must be ES6 compatible
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~resultCallback} [callback] result from exists.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.list = function(db, rootCollection, options, callback) {
-  var args = Array.prototype.slice.call(arguments, 1);
-  callback = typeof args[args.length - 1] === 'function' ? args.pop() : undefined;
-  rootCollection = args.length ? args.shift() : null;
-  options = args.length ? args.shift() : {};
-  options = options || {};
-
-  return executeLegacyOperation(db.s.topology, list, [db, rootCollection, options, callback], {
-    skipSessions: true
-  });
-};
-
-var list = function(db, rootCollection, options, callback) {
-  // Ensure we have correct values
-  if (rootCollection != null && typeof rootCollection === 'object') {
-    options = rootCollection;
-    rootCollection = null;
-  }
-
-  // Establish read preference
-  var readPreference = options.readPreference || ReadPreference.primary;
-  // Check if we are returning by id not filename
-  var byId = options['id'] != null ? options['id'] : false;
-  // Fetch item
-  var rootCollectionFinal =
-    rootCollection != null ? rootCollection : GridStore.DEFAULT_ROOT_COLLECTION;
-  var items = [];
-  db.collection(rootCollectionFinal + '.files', function(err, collection) {
-    if (err) return callback(err);
-
-    collection.find({}, { readPreference: readPreference }, function(err, cursor) {
-      if (err) return callback(err);
-
-      cursor.each(function(err, item) {
-        if (item != null) {
-          items.push(byId ? item._id : item.filename);
-        } else {
-          callback(err, items);
-        }
-      });
-    });
-  });
-};
-
-/**
- * Reads the contents of a file.
- *
- * This method has the following signatures
- *
- * (db, name, callback)
- * (db, name, length, callback)
- * (db, name, length, offset, callback)
- * (db, name, length, offset, options, callback)
- *
- * @method
- * @static
- * @param {Db} db the database to query.
- * @param {string} name The name of the file.
- * @param {number} [length] The size of data to read.
- * @param {number} [offset] The offset from the head of the file of which to start reading from.
- * @param {object} [options] Optional settings.
- * @param {(ReadPreference|string)} [options.readPreference] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
- * @param {object} [options.promiseLibrary] A Promise library class the application wishes to use such as Bluebird, must be ES6 compatible
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~readCallback} [callback] the command callback.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.read = function(db, name, length, offset, options, callback) {
-  var args = Array.prototype.slice.call(arguments, 2);
-  callback = typeof args[args.length - 1] === 'function' ? args.pop() : undefined;
-  length = args.length ? args.shift() : null;
-  offset = args.length ? args.shift() : null;
-  options = args.length ? args.shift() : null;
-  options = options || {};
-
-  return executeLegacyOperation(
-    db.s.topology,
-    readStatic,
-    [db, name, length, offset, options, callback],
-    { skipSessions: true }
-  );
-};
-
-var readStatic = function(db, name, length, offset, options, callback) {
-  new GridStore(db, name, 'r', options).open(function(err, gridStore) {
-    if (err) return callback(err);
-    // Make sure we are not reading out of bounds
-    if (offset && offset >= gridStore.length)
-      return callback('offset larger than size of file', null);
-    if (length && length > gridStore.length)
-      return callback('length is larger than the size of the file', null);
-    if (offset && length && offset + length > gridStore.length)
-      return callback('offset and length is larger than the size of the file', null);
-
-    if (offset != null) {
-      gridStore.seek(offset, function(err, gridStore) {
-        if (err) return callback(err);
-        gridStore.read(length, callback);
-      });
-    } else {
-      gridStore.read(length, callback);
-    }
-  });
-};
-
-/**
- * Read the entire file as a list of strings splitting by the provided separator.
- *
- * @method
- * @static
- * @param {Db} db the database to query.
- * @param {(String|object)} name the name of the file.
- * @param {string} [separator] The character to be recognized as the newline separator.
- * @param {object} [options] Optional settings.
- * @param {(ReadPreference|string)} [options.readPreference] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
- * @param {object} [options.promiseLibrary] A Promise library class the application wishes to use such as Bluebird, must be ES6 compatible
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~readlinesCallback} [callback] the command callback.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.readlines = function(db, name, separator, options, callback) {
-  var args = Array.prototype.slice.call(arguments, 2);
-  callback = typeof args[args.length - 1] === 'function' ? args.pop() : undefined;
-  separator = args.length ? args.shift() : null;
-  options = args.length ? args.shift() : null;
-  options = options || {};
-
-  return executeLegacyOperation(
-    db.s.topology,
-    readlinesStatic,
-    [db, name, separator, options, callback],
-    { skipSessions: true }
-  );
-};
-
-var readlinesStatic = function(db, name, separator, options, callback) {
-  var finalSeperator = separator == null ? '\n' : separator;
-  new GridStore(db, name, 'r', options).open(function(err, gridStore) {
-    if (err) return callback(err);
-    gridStore.readlines(finalSeperator, callback);
-  });
-};
-
-/**
- * Deletes the chunks and metadata information of a file from GridFS.
- *
- * @method
- * @static
- * @param {Db} db The database to query.
- * @param {(string|array)} names The name/names of the files to delete.
- * @param {object} [options] Optional settings.
- * @param {object} [options.promiseLibrary] A Promise library class the application wishes to use such as Bluebird, must be ES6 compatible
- * @param {ClientSession} [options.session] optional session to use for this operation
- * @param {GridStore~resultCallback} [callback] the command callback.
- * @return {Promise} returns Promise if no callback passed
- * @deprecated Use GridFSBucket API instead
- */
-GridStore.unlink = function(db, names, options, callback) {
-  var args = Array.prototype.slice.call(arguments, 2);
-  callback = typeof args[args.length - 1] === 'function' ? args.pop() : undefined;
-  options = args.length ? args.shift() : {};
-  options = options || {};
-
-  return executeLegacyOperation(db.s.topology, unlinkStatic, [this, db, names, options, callback], {
-    skipSessions: true
-  });
-};
-
-var unlinkStatic = function(self, db, names, options, callback) {
-  // Get the write concern
-  var writeConcern = _getWriteConcern(db, options);
-
-  // List of names
-  if (names.constructor === Array) {
-    var tc = 0;
-    for (var i = 0; i < names.length; i++) {
-      ++tc;
-      GridStore.unlink(db, names[i], options, function() {
-        if (--tc === 0) {
-          callback(null, self);
-        }
-      });
-    }
-  } else {
-    new GridStore(db, names, 'w', options).open(function(err, gridStore) {
-      if (err) return callback(err);
-      deleteChunks(gridStore, function(err) {
-        if (err) return callback(err);
-        gridStore.collection(function(err, collection) {
-          if (err) return callback(err);
-          collection.remove({ _id: gridStore.fileId }, writeConcern, function(err) {
-            callback(err, self);
-          });
-        });
-      });
-    });
-  }
-};
-
-/**
- *  @ignore
- */
-var _writeNormal = function(self, data, close, options, callback) {
-  // If we have a buffer write it using the writeBuffer method
-  if (Buffer.isBuffer(data)) {
-    return writeBuffer(self, data, close, callback);
-  } else {
-    return writeBuffer(self, Buffer.from(data, 'binary'), close, callback);
-  }
-};
-
-/**
- * @ignore
- */
-var _setWriteConcernHash = function(options) {
-  var finalOptions = {};
-  if (options.w != null) finalOptions.w = options.w;
-  if (options.journal === true) finalOptions.j = options.journal;
-  if (options.j === true) finalOptions.j = options.j;
-  if (options.fsync === true) finalOptions.fsync = options.fsync;
-  if (options.wtimeout != null) finalOptions.wtimeout = options.wtimeout;
-  return finalOptions;
-};
-
-/**
- * @ignore
- */
-var _getWriteConcern = function(self, options) {
-  // Final options
-  var finalOptions = { w: 1 };
-  options = options || {};
-
-  // Local options verification
-  if (
-    options.w != null ||
-    typeof options.j === 'boolean' ||
-    typeof options.journal === 'boolean' ||
-    typeof options.fsync === 'boolean'
-  ) {
-    finalOptions = _setWriteConcernHash(options);
-  } else if (options.safe != null && typeof options.safe === 'object') {
-    finalOptions = _setWriteConcernHash(options.safe);
-  } else if (typeof options.safe === 'boolean') {
-    finalOptions = { w: options.safe ? 1 : 0 };
-  } else if (
-    self.options.w != null ||
-    typeof self.options.j === 'boolean' ||
-    typeof self.options.journal === 'boolean' ||
-    typeof self.options.fsync === 'boolean'
-  ) {
-    finalOptions = _setWriteConcernHash(self.options);
-  } else if (
-    self.safe &&
-    (self.safe.w != null ||
-      typeof self.safe.j === 'boolean' ||
-      typeof self.safe.journal === 'boolean' ||
-      typeof self.safe.fsync === 'boolean')
-  ) {
-    finalOptions = _setWriteConcernHash(self.safe);
-  } else if (typeof self.safe === 'boolean') {
-    finalOptions = { w: self.safe ? 1 : 0 };
-  }
-
-  // Ensure we don't have an invalid combination of write concerns
-  if (
-    finalOptions.w < 1 &&
-    (finalOptions.journal === true || finalOptions.j === true || finalOptions.fsync === true)
-  )
-    throw MongoError.create({
-      message: 'No acknowledgement using w < 1 cannot be combined with journal:true or fsync:true',
-      driver: true
-    });
-
-  // Return the options
-  return finalOptions;
-};
-
-/**
- * Create a new GridStoreStream instance (INTERNAL TYPE, do not instantiate directly)
- *
- * @class
- * @extends external:Duplex
- * @return {GridStoreStream} a GridStoreStream instance.
- * @deprecated Use GridFSBucket API instead
- */
-var GridStoreStream = function(gs) {
-  // Initialize the duplex stream
-  Duplex.call(this);
-
-  // Get the gridstore
-  this.gs = gs;
-
-  // End called
-  this.endCalled = false;
-
-  // If we have a seek
-  this.totalBytesToRead = this.gs.length - this.gs.position;
-  this.seekPosition = this.gs.position;
-};
-
-//
-// Inherit duplex
-inherits(GridStoreStream, Duplex);
-
-GridStoreStream.prototype._pipe = GridStoreStream.prototype.pipe;
-
-// Set up override
-GridStoreStream.prototype.pipe = function(destination) {
-  var self = this;
-
-  // Only open gridstore if not already open
-  if (!self.gs.isOpen) {
-    self.gs.open(function(err) {
-      if (err) return self.emit('error', err);
-      self.totalBytesToRead = self.gs.length - self.gs.position;
-      self._pipe.apply(self, [destination]);
-    });
-  } else {
-    self.totalBytesToRead = self.gs.length - self.gs.position;
-    self._pipe.apply(self, [destination]);
-  }
-
-  return destination;
-};
-
-// Called by stream
-GridStoreStream.prototype._read = function() {
-  var self = this;
-
-  var read = function() {
-    // Read data
-    self.gs.read(length, function(err, buffer) {
-      if (err && !self.endCalled) return self.emit('error', err);
-
-      // Stream is closed
-      if (self.endCalled || buffer == null) return self.push(null);
-      // Remove bytes read
-      if (buffer.length <= self.totalBytesToRead) {
-        self.totalBytesToRead = self.totalBytesToRead - buffer.length;
-        self.push(buffer);
-      } else if (buffer.length > self.totalBytesToRead) {
-        self.totalBytesToRead = self.totalBytesToRead - buffer._index;
-        self.push(buffer.slice(0, buffer._index));
-      }
-
-      // Finished reading
-      if (self.totalBytesToRead <= 0) {
-        self.endCalled = true;
-      }
-    });
-  };
-
-  // Set read length
-  var length =
-    self.gs.length < self.gs.chunkSize ? self.gs.length - self.seekPosition : self.gs.chunkSize;
-  if (!self.gs.isOpen) {
-    self.gs.open(function(err) {
-      self.totalBytesToRead = self.gs.length - self.gs.position;
-      if (err) return self.emit('error', err);
-      read();
-    });
-  } else {
-    read();
-  }
-};
-
-GridStoreStream.prototype.destroy = function() {
-  this.pause();
-  this.endCalled = true;
-  this.gs.close();
-  this.emit('end');
-};
-
-GridStoreStream.prototype.write = function(chunk) {
-  var self = this;
-  if (self.endCalled)
-    return self.emit(
-      'error',
-      MongoError.create({ message: 'attempting to write to stream after end called', driver: true })
-    );
-  // Do we have to open the gridstore
-  if (!self.gs.isOpen) {
-    self.gs.open(function() {
-      self.gs.isOpen = true;
-      self.gs.write(chunk, function() {
-        process.nextTick(function() {
-          self.emit('drain');
-        });
-      });
-    });
-    return false;
-  } else {
-    self.gs.write(chunk, function() {
-      self.emit('drain');
-    });
-    return true;
-  }
-};
-
-GridStoreStream.prototype.end = function(chunk, encoding, callback) {
-  var self = this;
-  var args = Array.prototype.slice.call(arguments, 0);
-  callback = typeof args[args.length - 1] === 'function' ? args.pop() : undefined;
-  chunk = args.length ? args.shift() : null;
-  encoding = args.length ? args.shift() : null;
-  self.endCalled = true;
-
-  if (chunk) {
-    self.gs.write(chunk, function() {
-      self.gs.close(function() {
-        if (typeof callback === 'function') callback();
-        self.emit('end');
-      });
-    });
-  }
-
-  self.gs.close(function() {
-    if (typeof callback === 'function') callback();
-    self.emit('end');
-  });
-};
-
-/**
- * The read() method pulls some data out of the internal buffer and returns it. If there is no data available, then it will return null.
- * @function external:Duplex#read
- * @param {number} size Optional argument to specify how much data to read.
- * @return {(String | Buffer | null)}
- */
-
-/**
- * Call this function to cause the stream to return strings of the specified encoding instead of Buffer objects.
- * @function external:Duplex#setEncoding
- * @param {string} encoding The encoding to use.
- * @return {null}
- */
-
-/**
- * This method will cause the readable stream to resume emitting data events.
- * @function external:Duplex#resume
- * @return {null}
- */
-
-/**
- * This method will cause a stream in flowing-mode to stop emitting data events. Any data that becomes available will remain in the internal buffer.
- * @function external:Duplex#pause
- * @return {null}
- */
-
-/**
- * This method pulls all the data out of a readable stream, and writes it to the supplied destination, automatically managing the flow so that the destination is not overwhelmed by a fast readable stream.
- * @function external:Duplex#pipe
- * @param {Writable} destination The destination for writing data
- * @param {object} [options] Pipe options
- * @return {null}
- */
-
-/**
- * This method will remove the hooks set up for a previous pipe() call.
- * @function external:Duplex#unpipe
- * @param {Writable} [destination] The destination for writing data
- * @return {null}
- */
-
-/**
- * This is useful in certain cases where a stream is being consumed by a parser, which needs to "un-consume" some data that it has optimistically pulled out of the source, so that the stream can be passed on to some other party.
- * @function external:Duplex#unshift
- * @param {(Buffer|string)} chunk Chunk of data to unshift onto the read queue.
- * @return {null}
- */
-
-/**
- * Versions of Node prior to v0.10 had streams that did not implement the entire Streams API as it is today. (See "Compatibility" below for more information.)
- * @function external:Duplex#wrap
- * @param {Stream} stream An "old style" readable stream.
- * @return {null}
- */
-
-/**
- * This method writes some data to the underlying system, and calls the supplied callback once the data has been fully handled.
- * @function external:Duplex#write
- * @param {(string|Buffer)} chunk The data to write
- * @param {string} encoding The encoding, if chunk is a String
- * @param {function} callback Callback for when this chunk of data is flushed
- * @return {boolean}
- */
-
-/**
- * Call this method when no more data will be written to the stream. If supplied, the callback is attached as a listener on the finish event.
- * @function external:Duplex#end
- * @param {(string|Buffer)} chunk The data to write
- * @param {string} encoding The encoding, if chunk is a String
- * @param {function} callback Callback for when this chunk of data is flushed
- * @return {null}
- */
-
-/**
- * GridStoreStream stream data event, fired for each document in the cursor.
- *
- * @event GridStoreStream#data
- * @type {object}
- */
-
-/**
- * GridStoreStream stream end event
- *
- * @event GridStoreStream#end
- * @type {null}
- */
-
-/**
- * GridStoreStream stream close event
- *
- * @event GridStoreStream#close
- * @type {null}
- */
-
-/**
- * GridStoreStream stream readable event
- *
- * @event GridStoreStream#readable
- * @type {null}
- */
-
-/**
- * GridStoreStream stream drain event
- *
- * @event GridStoreStream#drain
- * @type {null}
- */
-
-/**
- * GridStoreStream stream finish event
- *
- * @event GridStoreStream#finish
- * @type {null}
- */
-
-/**
- * GridStoreStream stream pipe event
- *
- * @event GridStoreStream#pipe
- * @type {null}
- */
-
-/**
- * GridStoreStream stream unpipe event
- *
- * @event GridStoreStream#unpipe
- * @type {null}
- */
-
-/**
- * GridStoreStream stream error event
- *
- * @event GridStoreStream#error
- * @type {null}
- */
-
-/**
- * @ignore
- */
-module.exports = GridStore;