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From gar...@apache.org
Subject [38/52] [partial] couchdb-nmo git commit: prepare for release
Date Wed, 14 Oct 2015 10:09:35 GMT
http://git-wip-us.apache.org/repos/asf/couchdb-nmo/blob/753f1767/node_modules/couchbulkimporter/node_modules/mongodb/lib/gridfs/grid_store.js
----------------------------------------------------------------------
diff --git a/node_modules/couchbulkimporter/node_modules/mongodb/lib/gridfs/grid_store.js b/node_modules/couchbulkimporter/node_modules/mongodb/lib/gridfs/grid_store.js
new file mode 100644
index 0000000..62943bd
--- /dev/null
+++ b/node_modules/couchbulkimporter/node_modules/mongodb/lib/gridfs/grid_store.js
@@ -0,0 +1,1919 @@
+"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
+ * var MongoClient = require('mongodb').MongoClient,
+ *   GridStore = require('mongodb').GridStore,
+ *   ObjectID = require('mongodb').ObjectID,
+ *   test = require('assert');
+ *
+ * // Connection url
+ * var url = 'mongodb://localhost:27017/test';
+ * // Connect using MongoClient
+ * MongoClient.connect(url, function(err, db) {
+ *   var 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);
+ *           db.close();
+ *           test.done();
+ *         });
+ *       });
+ *     });
+ *   });
+ * });
+ */
+var Chunk = require('./chunk'),
+  ObjectID = require('mongodb-core').BSON.ObjectID,
+  ReadPreference = require('../read_preference'),
+  Buffer = require('buffer').Buffer,
+  Collection = require('../collection'),
+  fs = require('fs'),
+  timers = require('timers'),
+  f = require('util').format,
+  util = require('util'),
+  Define = require('../metadata'),
+  MongoError = require('mongodb-core').MongoError,
+  inherits = util.inherits,
+  Duplex = require('stream').Duplex || require('readable-stream').Duplex;
+
+var REFERENCE_BY_FILENAME = 0,
+  REFERENCE_BY_ID = 1;
+
+/**
+ * Namespace provided by the mongodb-core and node.js
+ * @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 overwriten.
+ *
+ * @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=null] Optional settings.
+ * @param {(number|string)} [options.w=null] The write concern.
+ * @param {number} [options.wtimeout=null] 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=null] Root collection to use. Defaults to **{GridStore.DEFAULT_ROOT_COLLECTION}**.
+ * @param {string} [options.content_type=null] 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=null] Arbitrary data the user wants to store.
+ * @param {object} [options.promiseLibrary=null] A Promise library class the application wishes to use such as Bluebird, must be ES6 compatible
+ * @param {(ReadPreference|string)} [options.readPreference=null] 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.
+ */
+var GridStore = function GridStore(db, id, filename, mode, options) {
+  if(!(this instanceof GridStore)) return new GridStore(db, id, filename, mode, options);
+  var self = this;
+  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 instanceof 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;
+
+  // No promise library selected fall back
+  if(!promiseLibrary) {
+    promiseLibrary = typeof global.Promise == 'function' ?
+      global.Promise : require('es6-promise').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)) {
+         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;
+     }
+  });
+}
+
+var define = GridStore.define = new Define('Gridstore', GridStore, true);
+
+/**
+ * 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 {GridStore~openCallback} [callback] this will be called after executing this method
+ * @return {Promise} returns Promise if no callback passed
+ */
+GridStore.prototype.open = function(callback) {
+  var self = this;
+  if( this.mode != "w" && this.mode != "w+" && this.mode != "r"){
+    throw MongoError.create({message: "Illegal mode " + this.mode, driver:true});
+  }
+
+  // We provided a callback leg
+  if(typeof callback == 'function') return open(self, callback);
+  // Return promise
+  return new self.promiseLibrary(function(resolve, reject) {
+    open(self, function(err, store) {
+      if(err) return reject(err);
+      resolve(store);
+    })
+  });
+};
+
+var open = function(self, 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(err, index) {
+      // Get chunk collection
+      var chunkCollection = self.chunkCollection();
+      // Ensure index on chunk collection
+      chunkCollection.ensureIndex([['files_id', 1], ['n', 1]], writeConcern, function(err, index) {
+        // 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);
+    });
+  }
+}
+
+// Push the definition for open
+define.classMethod('open', {callback: true, promise:true});
+
+/**
+ * Verify if the file is at EOF.
+ *
+ * @method
+ * @return {boolean} true if the read/write head is at the end of this file.
+ */
+GridStore.prototype.eof = function() {
+  return this.position == this.length ? true : false;
+}
+
+define.classMethod('eof', {callback: false, promise:false, returns: [Boolean]});
+
+/**
+ * The callback result format.
+ * @callback GridStore~resultCallback
+ * @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
+ */
+GridStore.prototype.getc = function(callback) {
+  var self = this;
+  // We provided a callback leg
+  if(typeof callback == 'function') return eof(self, callback);
+  // Return promise
+  return new self.promiseLibrary(function(resolve, reject) {
+    eof(self, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+}
+
+var eof = function(self, 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());
+  }
+}
+
+define.classMethod('getc', {callback: true, promise:true});
+
+/**
+ * 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 {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
+ */
+GridStore.prototype.puts = function(string, callback) {
+  var self = this;
+  var finalString = string.match(/\n$/) == null ? string + "\n" : string;
+  // We provided a callback leg
+  if(typeof callback == 'function') return this.write(finalString, callback);
+  // Return promise
+  return new self.promiseLibrary(function(resolve, reject) {
+    self.write(finalString, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+}
+
+define.classMethod('puts', {callback: true, promise:true});
+
+/**
+ * Return a modified Readable stream including a possible transform method.
+ *
+ * @method
+ * @return {GridStoreStream}
+ */
+GridStore.prototype.stream = function() {
+  return new GridStoreStream(this);
+}
+
+define.classMethod('stream', {callback: false, promise:false, returns: [GridStoreStream]});
+
+/**
+ * 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 {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
+ */
+GridStore.prototype.write = function write(data, close, callback) {
+  var self = this;
+  // We provided a callback leg
+  if(typeof callback == 'function') return _writeNormal(this, data, close, callback);
+  // Return promise
+  return new self.promiseLibrary(function(resolve, reject) {
+    _writeNormal(self, data, close, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+}
+
+define.classMethod('write', {callback: true, promise:true});
+
+/**
+ * Handles the destroy part of a stream
+ *
+ * @method
+ * @result {null}
+ */
+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');
+  }
+}
+
+define.classMethod('destroy', {callback: false, promise:false});
+
+/**
+ * Stores a file from the file system to the GridFS database.
+ *
+ * @method
+ * @param {(string|Buffer|FileHandle)} file the file to store.
+ * @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
+ */
+GridStore.prototype.writeFile = function (file, callback) {
+  var self = this;
+  // We provided a callback leg
+  if(typeof callback == 'function') return writeFile(self, file, callback);
+  // Return promise
+  return new self.promiseLibrary(function(resolve, reject) {
+    writeFile(self, file, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+};
+
+var writeFile = function(self, file, 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;
+      var numberOfChunksLeft = Math.min(stats.size / self.chunkSize);
+
+      // Write a chunk
+      var writeChunk = function() {
+        fs.read(file, self.chunkSize, offset, 'binary', function(err, data, bytesRead) {
+          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, function(err, chunk) {
+            if(err) return callback(err, self);
+
+            chunk.save({}, function(err, result) {
+              if(err) return callback(err, self);
+
+              self.position = self.position + data.length;
+
+              // Point to current chunk
+              self.currentChunk = chunk;
+
+              if(offset >= stats.size) {
+                fs.close(file);
+                self.close(function(err, result) {
+                  if(err) return callback(err, self);
+                  return callback(null, self);
+                });
+              } else {
+                return process.nextTick(writeChunk);
+              }
+            });
+          });
+        });
+      }
+
+      // Process the first write
+      process.nextTick(writeChunk);
+    });
+  });
+}
+
+define.classMethod('writeFile', {callback: true, promise:true});
+
+/**
+ * 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 {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
+ */
+GridStore.prototype.close = function(callback) {
+  var self = this;
+  // We provided a callback leg
+  if(typeof callback == 'function') return close(self, callback);
+  // Return promise
+  return new self.promiseLibrary(function(resolve, reject) {
+    close(self, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+};
+
+var close = function(self, callback) {
+  if(self.mode[0] == "w") {
+    // Set up options
+    var options = self.writeConcern;
+
+    if(self.currentChunk != null && self.currentChunk.position > 0) {
+      self.currentChunk.save({}, function(err, chunk) {
+        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) {
+            files.remove({'_id':self.fileId}, self.writeConcern, function(err, collection) {
+              if(err && typeof callback == 'function') return callback(err);
+
+              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}));
+  }
+}
+
+define.classMethod('close', {callback: true, promise: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}
+ */
+GridStore.prototype.chunkCollection = function(callback) {
+  if(typeof callback == 'function')
+    return this.db.collection((this.root + ".chunks"), callback);
+  return this.db.collection((this.root + ".chunks"));
+};
+
+define.classMethod('chunkCollection', {callback: true, promise:false, returns: [Collection]});
+
+/**
+ * Deletes all the chunks of this file in the database.
+ *
+ * @method
+ * @param {GridStore~resultCallback} [callback] the command callback.
+ * @return {Promise} returns Promise if no callback passed
+ */
+GridStore.prototype.unlink = function(callback) {
+  var self = this;
+  // We provided a callback leg
+  if(typeof callback == 'function') return unlink(self, callback);
+  // Return promise
+  return new self.promiseLibrary(function(resolve, reject) {
+    unlink(self, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+};
+
+var unlink = function(self, 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);
+      });
+    });
+  });
+}
+
+define.classMethod('unlink', {callback: true, promise:true});
+
+/**
+ * Retrieves the file collection associated with this object.
+ *
+ * @method
+ * @param {GridStore~collectionCallback} callback the command callback.
+ * @return {Collection}
+ */
+GridStore.prototype.collection = function(callback) {
+  if(typeof callback == 'function')
+    this.db.collection(this.root + ".files", callback);
+  return this.db.collection(this.root + ".files");
+};
+
+define.classMethod('collection', {callback: true, promise:false, returns: [Collection]});
+
+/**
+ * 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 {GridStore~readlinesCallback} [callback] the command callback.
+ * @return {Promise} returns Promise if no callback passed
+ */
+GridStore.prototype.readlines = function(separator, callback) {
+  var self = this;
+  var args = Array.prototype.slice.call(arguments, 0);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  separator = args.length ? args.shift() : "\n";
+  separator = separator || "\n";
+
+  // We provided a callback leg
+  if(typeof callback == 'function') return readlines(self, separator, callback);
+
+  // Return promise
+  return new self.promiseLibrary(function(resolve, reject) {
+    readlines(self, separator, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+};
+
+var readlines = function(self, separator, 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);
+  });
+}
+
+define.classMethod('readlines', {callback: true, promise:true});
+
+/**
+ * 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 {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
+ */
+GridStore.prototype.rewind = function(callback) {
+  var self = this;
+  // We provided a callback leg
+  if(typeof callback == 'function') return rewind(self, callback);
+  // Return promise
+  return new self.promiseLibrary(function(resolve, reject) {
+    rewind(self, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+};
+
+var rewind = function(self, callback) {
+  if(self.currentChunk.chunkNumber != 0) {
+    if(self.mode[0] == "w") {
+      deleteChunks(self, function(err, gridStore) {
+        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);
+  }
+}
+
+define.classMethod('rewind', {callback: true, promise:true});
+
+/**
+ * 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 {GridStore~readCallback} [callback] the command callback.
+ * @return {Promise} returns Promise if no callback passed
+ */
+GridStore.prototype.read = function(length, buffer, callback) {
+  var self = this;
+
+  var args = Array.prototype.slice.call(arguments, 0);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  length = args.length ? args.shift() : null;
+  buffer = args.length ? args.shift() : null;
+  // We provided a callback leg
+  if(typeof callback == 'function') return read(self, length, buffer, callback);
+  // Return promise
+  return new self.promiseLibrary(function(resolve, reject) {
+    read(self, length, buffer, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+}
+
+var read = function(self, length, buffer, 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 ? new Buffer(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
+  var 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);
+      }
+    }
+  });
+}
+
+define.classMethod('read', {callback: true, promise:true});
+
+/**
+ * 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 {GridStore~tellCallback} [callback] the command callback.
+ * @return {Promise} returns Promise if no callback passed
+ */
+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, reject) {
+    resolve(self.position);
+  });
+};
+
+define.classMethod('tell', {callback: true, promise:true});
+
+/**
+ * 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 {GridStore~gridStoreCallback} [callback] the command callback.
+ * @return {Promise} returns Promise if no callback passed
+ */
+GridStore.prototype.seek = function(position, seekLocation, callback) {
+  var self = this;
+
+  var args = Array.prototype.slice.call(arguments, 1);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  seekLocation = args.length ? args.shift() : null;
+
+  // We provided a callback leg
+  if(typeof callback == 'function') return seek(self, position, seekLocation, callback);
+  // Return promise
+  return new self.promiseLibrary(function(resolve, reject) {
+    seek(self, position, seekLocation, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+}
+
+var seek = function(self, position, seekLocation, 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) {
+      self.currentChunk = chunk;
+      self.position = targetPosition;
+      self.currentChunk.position = (self.position % self.chunkSize);
+      callback(err, self);
+    });
+  };
+
+  seekChunk();
+}
+
+define.classMethod('seek', {callback: true, promise:true});
+
+/**
+ * @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 instanceof 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") {
+        // Delete any existing chunks
+        deleteChunks(self, options, function(err, result) {
+          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);
+        });
+      }
+    });
+  } 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;
+
+    var collection2 = self.chunkCollection();
+    // No file exists set up write mode
+    if(self.mode == "w") {
+      // Delete any existing chunks
+      deleteChunks(self, options, function(err, result) {
+        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);
+        var 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, result) {
+          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, result) {
+                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, result) {
+          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, result) {
+      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=null] Optional settings.
+ * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
+ * @param {object} [options.promiseLibrary=null] A Promise library class the application wishes to use such as Bluebird, must be ES6 compatible
+ * @param {GridStore~resultCallback} [callback] result from exists.
+ * @return {Promise} returns Promise if no callback passed
+ */
+GridStore.exist = function(db, fileIdObject, rootCollection, options, callback) {
+  var args = Array.prototype.slice.call(arguments, 2);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  rootCollection = args.length ? args.shift() : null;
+  options = args.length ? args.shift() : {};
+  options = options || {};
+
+  // Get the promiseLibrary
+  var promiseLibrary = options.promiseLibrary;
+
+  // No promise library selected fall back
+  if(!promiseLibrary) {
+    promiseLibrary = typeof global.Promise == 'function' ?
+      global.Promise : require('es6-promise').Promise;
+  }
+
+  // We provided a callback leg
+  if(typeof callback == 'function') return exists(db, fileIdObject, rootCollection, options, callback);
+  // Return promise
+  return new promiseLibrary(function(resolve, reject) {
+    exists(db, fileIdObject, rootCollection, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+};
+
+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);
+    });
+  });
+}
+
+define.staticMethod('exist', {callback: true, promise: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=null] Optional settings.
+ * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
+ * @param {object} [options.promiseLibrary=null] A Promise library class the application wishes to use such as Bluebird, must be ES6 compatible
+ * @param {GridStore~resultCallback} [callback] result from exists.
+ * @return {Promise} returns Promise if no callback passed
+ */
+GridStore.list = function(db, rootCollection, options, callback) {
+  var args = Array.prototype.slice.call(arguments, 1);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  rootCollection = args.length ? args.shift() : null;
+  options = args.length ? args.shift() : {};
+  options = options || {};
+
+  // Get the promiseLibrary
+  var promiseLibrary = options.promiseLibrary;
+
+  // No promise library selected fall back
+  if(!promiseLibrary) {
+    promiseLibrary = typeof global.Promise == 'function' ?
+      global.Promise : require('es6-promise').Promise;
+  }
+
+  // We provided a callback leg
+  if(typeof callback == 'function') return list(db, rootCollection, options, callback);
+  // Return promise
+  return new promiseLibrary(function(resolve, reject) {
+    list(db, rootCollection, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+};
+
+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);
+        }
+      });
+    });
+  });
+}
+
+define.staticMethod('list', {callback: true, promise:true});
+
+/**
+ * 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=null] Optional settings.
+ * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
+ * @param {object} [options.promiseLibrary=null] A Promise library class the application wishes to use such as Bluebird, must be ES6 compatible
+ * @param {GridStore~readCallback} [callback] the command callback.
+ * @return {Promise} returns Promise if no callback passed
+ */
+
+GridStore.read = function(db, name, length, offset, options, callback) {
+  var args = Array.prototype.slice.call(arguments, 2);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  length = args.length ? args.shift() : null;
+  offset = args.length ? args.shift() : null;
+  options = args.length ? args.shift() : null;
+  options = options || {};
+
+  // Get the promiseLibrary
+  var promiseLibrary = options ? options.promiseLibrary : null;
+
+  // No promise library selected fall back
+  if(!promiseLibrary) {
+    promiseLibrary = typeof global.Promise == 'function' ?
+      global.Promise : require('es6-promise').Promise;
+  }
+
+  // We provided a callback leg
+  if(typeof callback == 'function') return readStatic(db, name, length, offset, options, callback);
+  // Return promise
+  return new promiseLibrary(function(resolve, reject) {
+    readStatic(db, name, length, offset, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+};
+
+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);
+    }
+  });
+}
+
+define.staticMethod('read', {callback: true, promise:true});
+
+/**
+ * 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=null] Optional settings.
+ * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
+ * @param {object} [options.promiseLibrary=null] A Promise library class the application wishes to use such as Bluebird, must be ES6 compatible
+ * @param {GridStore~readlinesCallback} [callback] the command callback.
+ * @return {Promise} returns Promise if no callback passed
+ */
+GridStore.readlines = function(db, name, separator, options, callback) {
+  var args = Array.prototype.slice.call(arguments, 2);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  separator = args.length ? args.shift() : null;
+  options = args.length ? args.shift() : null;
+  options = options || {};
+
+  // Get the promiseLibrary
+  var promiseLibrary = options ? options.promiseLibrary : null;
+
+  // No promise library selected fall back
+  if(!promiseLibrary) {
+    promiseLibrary = typeof global.Promise == 'function' ?
+      global.Promise : require('es6-promise').Promise;
+  }
+
+  // We provided a callback leg
+  if(typeof callback == 'function') return readlinesStatic(db, name, separator, options, callback);
+  // Return promise
+  return new promiseLibrary(function(resolve, reject) {
+    readlinesStatic(db, name, separator, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+};
+
+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);
+  });
+}
+
+define.staticMethod('readlines', {callback: true, promise:true});
+
+/**
+ * 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=null] Optional settings.
+ * @param {object} [options.promiseLibrary=null] A Promise library class the application wishes to use such as Bluebird, must be ES6 compatible
+ * @param {GridStore~resultCallback} [callback] the command callback.
+ * @return {Promise} returns Promise if no callback passed
+ */
+GridStore.unlink = function(db, names, options, callback) {
+  var self = this;
+  var args = Array.prototype.slice.call(arguments, 2);
+  callback = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  options = args.length ? args.shift() : {};
+  options = options || {};
+
+  // Get the promiseLibrary
+  var promiseLibrary = options.promiseLibrary;
+
+  // No promise library selected fall back
+  if(!promiseLibrary) {
+    promiseLibrary = typeof global.Promise == 'function' ?
+      global.Promise : require('es6-promise').Promise;
+  }
+
+  // We provided a callback leg
+  if(typeof callback == 'function') return unlinkStatic(self, db, names, options, callback);
+
+  // Return promise
+  return new promiseLibrary(function(resolve, reject) {
+    unlinkStatic(self, db, names, options, function(err, r) {
+      if(err) return reject(err);
+      resolve(r);
+    })
+  });
+};
+
+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(result) {
+        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, result) {
+        if(err) return callback(err);
+        gridStore.collection(function(err, collection) {
+          if(err) return callback(err);
+          collection.remove({'_id':gridStore.fileId}, writeConcern, function(err, result) {
+            callback(err, self);
+          });
+        });
+      });
+    });
+  }
+}
+
+define.staticMethod('unlink', {callback: true, promise:true});
+
+/**
+ *  @ignore
+ */
+var _writeNormal = function(self, data, close, 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, new Buffer(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.
+ */
+var GridStoreStream = function(gs) {
+  var self = this;
+  // 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]);
+  }
+}
+
+// Called by stream
+GridStoreStream.prototype._read = function(n) {
+  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, gs) {
+      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, encoding, callback) {
+  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 = args.pop();
+  if(typeof callback != 'function') args.push(callback);
+  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;

http://git-wip-us.apache.org/repos/asf/couchdb-nmo/blob/753f1767/node_modules/couchbulkimporter/node_modules/mongodb/lib/metadata.js
----------------------------------------------------------------------
diff --git a/node_modules/couchbulkimporter/node_modules/mongodb/lib/metadata.js b/node_modules/couchbulkimporter/node_modules/mongodb/lib/metadata.js
new file mode 100644
index 0000000..7dae562
--- /dev/null
+++ b/node_modules/couchbulkimporter/node_modules/mongodb/lib/metadata.js
@@ -0,0 +1,64 @@
+var f = require('util').format;
+
+var Define = function(name, object, stream) {
+  this.name = name;
+  this.object = object;
+  this.stream = typeof stream == 'boolean' ? stream : false;
+  this.instrumentations = {};
+}
+
+Define.prototype.classMethod = function(name, options) {
+  var keys = Object.keys(options).sort();
+  var key = generateKey(keys, options);
+
+  // Add a list of instrumentations
+  if(this.instrumentations[key] == null) {
+    this.instrumentations[key] = {
+      methods: [], options: options
+    }
+  }
+
+  // Push to list of method for this instrumentation
+  this.instrumentations[key].methods.push(name);
+}
+
+var generateKey = function(keys, options) {
+  var parts = [];
+  for(var i = 0; i < keys.length; i++) {
+    parts.push(f('%s=%s', keys[i], options[keys[i]]));
+  }
+
+  return parts.join();
+}
+
+Define.prototype.staticMethod = function(name, options) {
+  options.static = true;
+  var keys = Object.keys(options).sort();
+  var key = generateKey(keys, options);
+
+  // Add a list of instrumentations
+  if(this.instrumentations[key] == null) {
+    this.instrumentations[key] = {
+      methods: [], options: options
+    }
+  }
+
+  // Push to list of method for this instrumentation
+  this.instrumentations[key].methods.push(name);
+}
+
+Define.prototype.generate = function(keys, options) {
+  // Generate the return object
+  var object = {
+    name: this.name, obj: this.object, stream: this.stream,
+    instrumentations: []
+  }
+
+  for(var name in this.instrumentations) {
+    object.instrumentations.push(this.instrumentations[name]);
+  }
+
+  return object;
+}
+
+module.exports = Define;
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/couchdb-nmo/blob/753f1767/node_modules/couchbulkimporter/node_modules/mongodb/lib/mongo_client.js
----------------------------------------------------------------------
diff --git a/node_modules/couchbulkimporter/node_modules/mongodb/lib/mongo_client.js b/node_modules/couchbulkimporter/node_modules/mongodb/lib/mongo_client.js
new file mode 100644
index 0000000..3ce2ad6
--- /dev/null
+++ b/node_modules/couchbulkimporter/node_modules/mongodb/lib/mongo_client.js
@@ -0,0 +1,463 @@
+"use strict";
+
+var parse = require('./url_parser')
+  , Server = require('./server')
+  , Mongos = require('./mongos')
+  , ReplSet = require('./replset')
+  , Define = require('./metadata')
+  , ReadPreference = require('./read_preference')
+  , Db = require('./db');
+
+/**
+ * @fileOverview The **MongoClient** class is a class that allows for making Connections to MongoDB.
+ *
+ * @example
+ * var MongoClient = require('mongodb').MongoClient,
+ *   test = require('assert');
+ * // Connection url
+ * var url = 'mongodb://localhost:27017/test';
+ * // Connect using MongoClient
+ * MongoClient.connect(url, function(err, db) {
+ *   // Get an additional db
+ *   db.close();
+ * });
+ */
+
+/**
+ * Creates a new MongoClient instance
+ * @class
+ * @return {MongoClient} a MongoClient instance.
+ */
+function MongoClient() {
+  /**
+   * The callback format for results
+   * @callback MongoClient~connectCallback
+   * @param {MongoError} error An error instance representing the error during the execution.
+   * @param {Db} db The connected database.
+   */
+
+  /**
+   * Connect to MongoDB using a url as documented at
+   *
+   *  docs.mongodb.org/manual/reference/connection-string/
+   *
+   * Note that for replicasets the replicaSet query parameter is required in the 2.0 driver
+   *
+   * @method
+   * @param {string} url The connection URI string
+   * @param {object} [options=null] Optional settings.
+   * @param {boolean} [options.uri_decode_auth=false] Uri decode the user name and password for authentication
+   * @param {object} [options.db=null] A hash of options to set on the db object, see **Db constructor**
+   * @param {object} [options.server=null] A hash of options to set on the server objects, see **Server** constructor**
+   * @param {object} [options.replSet=null] A hash of options to set on the replSet object, see **ReplSet** constructor**
+   * @param {object} [options.mongos=null] A hash of options to set on the mongos object, see **Mongos** constructor**
+   * @param {object} [options.promiseLibrary=null] A Promise library class the application wishes to use such as Bluebird, must be ES6 compatible
+   * @param {MongoClient~connectCallback} [callback] The command result callback
+   * @return {Promise} returns Promise if no callback passed
+   */
+  this.connect = MongoClient.connect;
+}
+
+var define = MongoClient.define = new Define('MongoClient', MongoClient, false);
+
+/**
+ * Connect to MongoDB using a url as documented at
+ *
+ *  docs.mongodb.org/manual/reference/connection-string/
+ *
+ * Note that for replicasets the replicaSet query parameter is required in the 2.0 driver
+ *
+ * @method
+ * @static
+ * @param {string} url The connection URI string
+ * @param {object} [options=null] Optional settings.
+ * @param {boolean} [options.uri_decode_auth=false] Uri decode the user name and password for authentication
+ * @param {object} [options.db=null] A hash of options to set on the db object, see **Db constructor**
+ * @param {object} [options.server=null] A hash of options to set on the server objects, see **Server** constructor**
+ * @param {object} [options.replSet=null] A hash of options to set on the replSet object, see **ReplSet** constructor**
+ * @param {object} [options.mongos=null] A hash of options to set on the mongos object, see **Mongos** constructor**
+ * @param {object} [options.promiseLibrary=null] A Promise library class the application wishes to use such as Bluebird, must be ES6 compatible
+ * @param {MongoClient~connectCallback} [callback] The command result callback
+ * @return {Promise} returns Promise if no callback passed
+ */
+MongoClient.connect = function(url, options, callback) {
+  var args = Array.prototype.slice.call(arguments, 1);
+  callback = typeof args[args.length - 1] == 'function' ? args.pop() : null;
+  options = args.length ? args.shift() : null;
+  options = options || {};
+
+  // Get the promiseLibrary
+  var promiseLibrary = options.promiseLibrary;
+
+  // No promise library selected fall back
+  if(!promiseLibrary) {
+    promiseLibrary = typeof global.Promise == 'function' ?
+      global.Promise : require('es6-promise').Promise;
+  }
+
+  // Return a promise
+  if(typeof callback != 'function') {
+    return new promiseLibrary(function(resolve, reject) {
+      connect(url, options, function(err, db) {
+        if(err) return reject(err);
+        resolve(db);
+      });
+    });
+  }
+
+  // Fallback to callback based connect
+  connect(url, options, callback);
+}
+
+define.staticMethod('connect', {callback: true, promise:true});
+
+var connect = function(url, options, callback) {
+  var serverOptions = options.server || {};
+  var mongosOptions = options.mongos || {};
+  var replSetServersOptions = options.replSet || options.replSetServers || {};
+  var dbOptions = options.db || {};
+
+  // If callback is null throw an exception
+  if(callback == null)
+    throw new Error("no callback function provided");
+
+  // Parse the string
+  var object = parse(url, options);
+
+  // Merge in any options for db in options object
+  if(dbOptions) {
+    for(var name in dbOptions) object.db_options[name] = dbOptions[name];
+  }
+
+  // Added the url to the options
+  object.db_options.url = url;
+
+  // Merge in any options for server in options object
+  if(serverOptions) {
+    for(var name in serverOptions) object.server_options[name] = serverOptions[name];
+  }
+
+  // Merge in any replicaset server options
+  if(replSetServersOptions) {
+    for(var name in replSetServersOptions) object.rs_options[name] = replSetServersOptions[name];
+  }
+
+  if(replSetServersOptions.ssl
+    || replSetServersOptions.sslValidate
+    || replSetServersOptions.sslCA
+    || replSetServersOptions.sslCert
+    || replSetServersOptions.sslKey
+    || replSetServersOptions.sslPass) {
+    object.server_options.ssl = replSetServersOptions.ssl;
+    object.server_options.sslValidate = replSetServersOptions.sslValidate;
+    object.server_options.sslCA = replSetServersOptions.sslCA;
+    object.server_options.sslCert = replSetServersOptions.sslCert;
+    object.server_options.sslKey = replSetServersOptions.sslKey;
+    object.server_options.sslPass = replSetServersOptions.sslPass;
+  }
+
+  // Merge in any replicaset server options
+  if(mongosOptions) {
+    for(var name in mongosOptions) object.mongos_options[name] = mongosOptions[name];
+  }
+
+  if(typeof object.server_options.poolSize == 'number') {
+    if(!object.mongos_options.poolSize) object.mongos_options.poolSize = object.server_options.poolSize;
+    if(!object.rs_options.poolSize) object.rs_options.poolSize = object.server_options.poolSize;
+  }
+
+  if(mongosOptions.ssl
+    || mongosOptions.sslValidate
+    || mongosOptions.sslCA
+    || mongosOptions.sslCert
+    || mongosOptions.sslKey
+    || mongosOptions.sslPass) {
+    object.server_options.ssl = mongosOptions.ssl;
+    object.server_options.sslValidate = mongosOptions.sslValidate;
+    object.server_options.sslCA = mongosOptions.sslCA;
+    object.server_options.sslCert = mongosOptions.sslCert;
+    object.server_options.sslKey = mongosOptions.sslKey;
+    object.server_options.sslPass = mongosOptions.sslPass;
+  }
+
+  // Set the promise library
+  object.db_options.promiseLibrary = options.promiseLibrary;
+
+  // We need to ensure that the list of servers are only either direct members or mongos
+  // they cannot be a mix of monogs and mongod's
+  var totalNumberOfServers = object.servers.length;
+  var totalNumberOfMongosServers = 0;
+  var totalNumberOfMongodServers = 0;
+  var serverConfig = null;
+  var errorServers = {};
+
+  // Failure modes
+  if(object.servers.length == 0) throw new Error("connection string must contain at least one seed host");
+
+  // If we have no db setting for the native parser try to set the c++ one first
+  object.db_options.native_parser = _setNativeParser(object.db_options);
+  // If no auto_reconnect is set, set it to true as default for single servers
+  if(typeof object.server_options.auto_reconnect != 'boolean') {
+    object.server_options.auto_reconnect = true;
+  }
+
+  // If we have more than a server, it could be replicaset or mongos list
+  // need to verify that it's one or the other and fail if it's a mix
+  // Connect to all servers and run ismaster
+  for(var i = 0; i < object.servers.length; i++) {
+    // Set up socket options
+    var providedSocketOptions = object.server_options.socketOptions || {};
+
+    var _server_options = {
+        poolSize:1
+      , socketOptions: {
+          connectTimeoutMS: providedSocketOptions.connectTimeoutMS || 30000
+        , socketTimeoutMS:  providedSocketOptions.socketTimeoutMS || 30000
+      }
+      , auto_reconnect:false};
+
+    // Ensure we have ssl setup for the servers
+    if(object.server_options.ssl) {
+      _server_options.ssl = object.server_options.ssl;
+      _server_options.sslValidate = object.server_options.sslValidate;
+      _server_options.sslCA = object.server_options.sslCA;
+      _server_options.sslCert = object.server_options.sslCert;
+      _server_options.sslKey = object.server_options.sslKey;
+      _server_options.sslPass = object.server_options.sslPass;
+    } else if(object.rs_options.ssl) {
+      _server_options.ssl = object.rs_options.ssl;
+      _server_options.sslValidate = object.rs_options.sslValidate;
+      _server_options.sslCA = object.rs_options.sslCA;
+      _server_options.sslCert = object.rs_options.sslCert;
+      _server_options.sslKey = object.rs_options.sslKey;
+      _server_options.sslPass = object.rs_options.sslPass;
+    }
+
+    // Error
+    var error = null;
+    // Set up the Server object
+    var _server = object.servers[i].domain_socket
+        ? new Server(object.servers[i].domain_socket, _server_options)
+        : new Server(object.servers[i].host, object.servers[i].port, _server_options);
+
+    var connectFunction = function(__server) {
+      // Attempt connect
+      new Db(object.dbName, __server, {w:1, native_parser:false, promiseLibrary:options.promiseLibrary}).open(function(err, db) {
+        // Update number of servers
+        totalNumberOfServers = totalNumberOfServers - 1;
+        
+        // If no error do the correct checks
+        if(!err) {
+          // Close the connection
+          db.close();
+          var isMasterDoc = db.serverConfig.isMasterDoc;
+          
+          // Check what type of server we have
+          if(isMasterDoc.setName) {
+            totalNumberOfMongodServers++;
+          }
+
+          if(isMasterDoc.msg && isMasterDoc.msg == "isdbgrid") totalNumberOfMongosServers++;
+        } else {
+          error = err;
+          errorServers[__server.host + ":" + __server.port] = __server;
+        }
+
+        if(totalNumberOfServers == 0) {
+          // Error out
+          if(totalNumberOfMongodServers == 0 && totalNumberOfMongosServers == 0 && error) {
+            return callback(error, null);
+          }
+
+          // If we have a mix of mongod and mongos, throw an error
+          if(totalNumberOfMongosServers > 0 && totalNumberOfMongodServers > 0) {
+            if(db) db.close();
+            return process.nextTick(function() {
+              try {
+                callback(new Error("cannot combine a list of replicaset seeds and mongos seeds"));
+              } catch (err) {
+                throw err
+              }
+            })
+          }
+
+          if(totalNumberOfMongodServers == 0
+            && totalNumberOfMongosServers == 0
+            && object.servers.length == 1
+            && (!object.rs_options.replicaSet || !object.rs_options.rs_name)) {
+            
+            var obj = object.servers[0];
+            serverConfig = obj.domain_socket ?
+                new Server(obj.domain_socket, object.server_options)
+              : new Server(obj.host, obj.port, object.server_options);
+          
+          } else if(totalNumberOfMongodServers > 0
+            || totalNumberOfMongosServers > 0
+            || object.rs_options.replicaSet || object.rs_options.rs_name) {
+            
+            var finalServers = object.servers
+              .filter(function(serverObj) {
+                return errorServers[serverObj.host + ":" + serverObj.port] == null;
+              })
+              .map(function(serverObj) {
+                return new Server(serverObj.host, serverObj.port, object.server_options);
+              });
+
+            // Clean out any error servers
+            errorServers = {};
+
+            // Set up the final configuration
+            if(totalNumberOfMongodServers > 0) {
+              try {
+                
+                // If no replicaset name was provided, we wish to perform a
+                // direct connection
+                if(totalNumberOfMongodServers == 1 
+                  && (!object.rs_options.replicaSet && !object.rs_options.rs_name)) {
+                  serverConfig = finalServers[0];
+                } else if(totalNumberOfMongodServers == 1) {
+                  object.rs_options.replicaSet = object.rs_options.replicaSet || object.rs_options.rs_name;
+                  serverConfig = new ReplSet(finalServers, object.rs_options);
+                } else {
+                  serverConfig = new ReplSet(finalServers, object.rs_options);                  
+                }
+
+              } catch(err) {
+                return callback(err, null);
+              }
+            } else {
+              serverConfig = new Mongos(finalServers, object.mongos_options);
+            }
+          }
+
+          if(serverConfig == null) {
+            return process.nextTick(function() {
+              try {
+                callback(new Error("Could not locate any valid servers in initial seed list"));
+              } catch (err) {
+                if(db) db.close();
+                throw err
+              }
+            });
+          }
+
+          // Ensure no firing of open event before we are ready
+          serverConfig.emitOpen = false;
+          // Set up all options etc and connect to the database
+          _finishConnecting(serverConfig, object, options, callback)
+        }
+      });
+    }
+
+    // Wrap the context of the call
+    connectFunction(_server);
+  }
+}
+
+var _setNativeParser = function(db_options) {
+  if(typeof db_options.native_parser == 'boolean') return db_options.native_parser;
+
+  try {
+    require('mongodb-core').BSON.BSONNative.BSON;
+    return true;
+  } catch(err) {
+    return false;
+  }
+}
+
+var _finishConnecting = function(serverConfig, object, options, callback) {
+  // If we have a readPreference passed in by the db options
+  if(typeof object.db_options.readPreference == 'string') {
+    object.db_options.readPreference = new ReadPreference(object.db_options.readPreference);
+  } else if(typeof object.db_options.read_preference == 'string') {
+    object.db_options.readPreference = new ReadPreference(object.db_options.read_preference);
+  }
+
+  // Do we have readPreference tags
+  if(object.db_options.readPreference && object.db_options.readPreferenceTags) {
+    object.db_options.readPreference.tags = object.db_options.readPreferenceTags;
+  } else if(object.db_options.readPreference && object.db_options.read_preference_tags) {
+    object.db_options.readPreference.tags = object.db_options.read_preference_tags;
+  }
+
+  // Get the socketTimeoutMS
+  var socketTimeoutMS = object.server_options.socketOptions.socketTimeoutMS || 0;
+
+  // If we have a replset, override with replicaset socket timeout option if available
+  if(serverConfig instanceof ReplSet) {
+    socketTimeoutMS = object.rs_options.socketOptions.socketTimeoutMS || socketTimeoutMS;
+  }
+
+  // Set socketTimeout to the same as the connectTimeoutMS or 30 sec
+  serverConfig.connectTimeoutMS = serverConfig.connectTimeoutMS || 30000;
+  serverConfig.socketTimeoutMS = serverConfig.connectTimeoutMS;
+
+  // Set up the db options
+  var db = new Db(object.dbName, serverConfig, object.db_options);
+  // Open the db
+  db.open(function(err, db){
+
+    if(err) {
+      return process.nextTick(function() {
+        try {
+          callback(err, null);
+        } catch (err) {
+          if(db) db.close();
+          throw err
+        }
+      });
+    }
+
+    // Reset the socket timeout
+    serverConfig.socketTimeoutMS = socketTimeoutMS || 0;
+
+    // Return object
+    if(err == null && object.auth){
+      // What db to authenticate against
+      var authentication_db = db;
+      if(object.db_options && object.db_options.authSource) {
+        authentication_db = db.db(object.db_options.authSource);
+      }
+
+      // Build options object
+      var options = {};
+      if(object.db_options.authMechanism) options.authMechanism = object.db_options.authMechanism;
+      if(object.db_options.gssapiServiceName) options.gssapiServiceName = object.db_options.gssapiServiceName;
+
+      // Authenticate
+      authentication_db.authenticate(object.auth.user, object.auth.password, options, function(err, success){
+        if(success){
+          process.nextTick(function() {
+            try {
+              callback(null, db);
+            } catch (err) {
+              if(db) db.close();
+              throw err
+            }
+          });
+        } else {
+          if(db) db.close();
+          process.nextTick(function() {
+            try {
+              callback(err ? err : new Error('Could not authenticate user ' + object.auth[0]), null);
+            } catch (err) {
+              if(db) db.close();
+              throw err
+            }
+          });
+        }
+      });
+    } else {
+      process.nextTick(function() {
+        try {
+          callback(err, db);
+        } catch (err) {
+          if(db) db.close();
+          throw err
+        }
+      })
+    }
+  });
+}
+
+module.exports = MongoClient


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