Node.js MongoDB Driver API

Source: lib/cursor.js

  1. "use strict";
  3. var inherits = require('util').inherits
  4.   , f = require('util').format
  5.   , formattedOrderClause = require('./utils').formattedOrderClause
  6.   , handleCallback = require('./utils').handleCallback
  7.   , ReadPreference = require('./read_preference')
  8.   , MongoError = require('mongodb-core').MongoError
  9.   , Readable = require('stream').Readable || require('readable-stream').Readable
  10.   , Define = require('./metadata')
  11.   , CoreCursor = require('mongodb-core').Cursor
  12.   , Map = require('mongodb-core').BSON.Map
  13.   , CoreReadPreference = require('mongodb-core').ReadPreference;
  15. /**
  16.  * @fileOverview The **Cursor** class is an internal class that embodies a cursor on MongoDB
  17.  * allowing for iteration over the results returned from the underlying query. It supports
  18.  * one by one document iteration, conversion to an array or can be iterated as a Node 0.10.X
  19.  * or higher stream
  20.  *
  21.  * **CURSORS Cannot directly be instantiated**
  22.  * @example
  23.  * var MongoClient = require('mongodb').MongoClient,
  24.  *   test = require('assert');
  25.  * // Connection url
  26.  * var url = 'mongodb://localhost:27017/test';
  27.  * // Connect using MongoClient
  28.  * MongoClient.connect(url, function(err, db) {
  29.  *   // Create a collection we want to drop later
  30.  *   var col = db.collection('createIndexExample1');
  31.  *   // Insert a bunch of documents
  32.  *   col.insert([{a:1, b:1}
  33.  *     , {a:2, b:2}, {a:3, b:3}
  34.  *     , {a:4, b:4}], {w:1}, function(err, result) {
  35.  *     test.equal(null, err);
  36.  *
  37.  *     // Show that duplicate records got dropped
  38.  *     col.find({}).toArray(function(err, items) {
  39.  *       test.equal(null, err);
  40.  *       test.equal(4, items.length);
  41.  *       db.close();
  42.  *     });
  43.  *   });
  44.  * });
  45.  */
  47. /**
  48.  * Namespace provided by the mongodb-core and node.js
  49.  * @external CoreCursor
  50.  * @external Readable
  51.  */
  53. // Flags allowed for cursor
  54. var flags = ['tailable', 'oplogReplay', 'noCursorTimeout', 'awaitData', 'exhaust', 'partial'];
  55. var fields = ['numberOfRetries', 'tailableRetryInterval'];
  56. var push = Array.prototype.push;
  58. /**
  59.  * Creates a new Cursor instance (INTERNAL TYPE, do not instantiate directly)
  60.  * @class Cursor
  61.  * @extends external:CoreCursor
  62.  * @extends external:Readable
  63.  * @property {string} sortValue Cursor query sort setting.
  64.  * @property {boolean} timeout Is Cursor able to time out.
  65.  * @property {ReadPreference} readPreference Get cursor ReadPreference.
  66.  * @fires Cursor#data
  67.  * @fires Cursor#end
  68.  * @fires Cursor#close
  69.  * @fires Cursor#readable
  70.  * @return {Cursor} a Cursor instance.
  71.  * @example
  72.  * Cursor cursor options.
  73.  *
  74.  * collection.find({}).project({a:1})                             // Create a projection of field a
  75.  * collection.find({}).skip(1).limit(10)                          // Skip 1 and limit 10
  76.  * collection.find({}).batchSize(5)                               // Set batchSize on cursor to 5
  77.  * collection.find({}).filter({a:1})                              // Set query on the cursor
  78.  * collection.find({}).comment('add a comment')                   // Add a comment to the query, allowing to correlate queries
  79.  * collection.find({}).addCursorFlag('tailable', true)            // Set cursor as tailable
  80.  * collection.find({}).addCursorFlag('oplogReplay', true)         // Set cursor as oplogReplay
  81.  * collection.find({}).addCursorFlag('noCursorTimeout', true)     // Set cursor as noCursorTimeout
  82.  * collection.find({}).addCursorFlag('awaitData', true)           // Set cursor as awaitData
  83.  * collection.find({}).addCursorFlag('partial', true)             // Set cursor as partial
  84.  * collection.find({}).addQueryModifier('$orderby', {a:1})        // Set $orderby {a:1}
  85.  * collection.find({}).max(10)                                    // Set the cursor maxScan
  86.  * collection.find({}).maxScan(10)                                // Set the cursor maxScan
  87.  * collection.find({}).maxTimeMS(1000)                            // Set the cursor maxTimeMS
  88.  * collection.find({}).min(100)                                   // Set the cursor min
  89.  * collection.find({}).returnKey(10)                              // Set the cursor returnKey
  90.  * collection.find({}).setReadPreference(ReadPreference.PRIMARY)  // Set the cursor readPreference
  91.  * collection.find({}).showRecordId(true)                         // Set the cursor showRecordId
  92.  * collection.find({}).snapshot(true)                             // Set the cursor snapshot
  93.  * collection.find({}).sort([['a', 1]])                           // Sets the sort order of the cursor query
  94.  * collection.find({}).hint('a_1')                                // Set the cursor hint
  95.  *
  96.  * All options are chainable, so one can do the following.
  97.  *
  98.  * collection.find({}).maxTimeMS(1000).maxScan(100).skip(1).toArray(..)
  99.  */
  100. var Cursor = function(bson, ns, cmd, options, topology, topologyOptions) {
  101.   CoreCursor.apply(this, Array.prototype.slice.call(arguments, 0));
  102.   var self = this;
  103.   var state = Cursor.INIT;
  104.   var streamOptions = {};
  106.   // Tailable cursor options
  107.   var numberOfRetries = options.numberOfRetries || 5;
  108.   var tailableRetryInterval = options.tailableRetryInterval || 500;
  109.   var currentNumberOfRetries = numberOfRetries;
  111.   // Get the promiseLibrary
  112.   var promiseLibrary = options.promiseLibrary;
  114.   // No promise library selected fall back
  115.   if(!promiseLibrary) {
  116.     promiseLibrary = typeof global.Promise == 'function' ?
  117.       global.Promise : require('es6-promise').Promise;
  118.   }
  120.   // Set up
  121.   Readable.call(this, {objectMode: true});
  123.   // Internal cursor state
  124.   this.s = {
  125.     // Tailable cursor options
  126.       numberOfRetries: numberOfRetries
  127.     , tailableRetryInterval: tailableRetryInterval
  128.     , currentNumberOfRetries: currentNumberOfRetries
  129.     // State
  130.     , state: state
  131.     // Stream options
  132.     , streamOptions: streamOptions
  133.     // BSON
  134.     , bson: bson
  135.     // Namespace
  136.     , ns: ns
  137.     // Command
  138.     , cmd: cmd
  139.     // Options
  140.     , options: options
  141.     // Topology
  142.     , topology: topology
  143.     // Topology options
  144.     , topologyOptions: topologyOptions
  145.     // Promise library
  146.     , promiseLibrary: promiseLibrary
  147.     // Current doc
  148.     , currentDoc: null
  149.   }
  151.   // Translate correctly
  152.   if(self.s.options.noCursorTimeout == true) {
  153.     self.addCursorFlag('noCursorTimeout', true);
  154.   }
  156.   // Set the sort value
  157.   this.sortValue = self.s.cmd.sort;
  159.   // Get the batchSize
  160.   var batchSize = cmd.cursor && cmd.cursor.batchSize
  161.     ? cmd.cursor && cmd.cursor.batchSize
  162.     : (options.cursor && options.cursor.batchSize ? options.cursor.batchSize : 1000);
  164.   // Set the batchSize
  165.   this.setCursorBatchSize(batchSize);
  166. }
  168. /**
  169.  * Cursor stream data event, fired for each document in the cursor.
  170.  *
  171.  * @event Cursor#data
  172.  * @type {object}
  173.  */
  175. /**
  176.  * Cursor stream end event
  177.  *
  178.  * @event Cursor#end
  179.  * @type {null}
  180.  */
  182. /**
  183.  * Cursor stream close event
  184.  *
  185.  * @event Cursor#close
  186.  * @type {null}
  187.  */
  189. /**
  190.  * Cursor stream readable event
  191.  *
  192.  * @event Cursor#readable
  193.  * @type {null}
  194.  */
  196. // Inherit from Readable
  197. inherits(Cursor, Readable);
  199. // Map core cursor _next method so we can apply mapping
  200. CoreCursor.prototype._next = CoreCursor.prototype.next;
  202. for(var name in CoreCursor.prototype) {
  203.   Cursor.prototype[name] = CoreCursor.prototype[name];
  204. }
  206. var define = Cursor.define = new Define('Cursor', Cursor, true);
  208. /**
  209.  * Check if there is any document still available in the cursor
  210.  * @method
  211.  * @param {Cursor~resultCallback} [callback] The result callback.
  212.  * @throws {MongoError}
  213.  * @return {Promise} returns Promise if no callback passed
  214.  */
  215. Cursor.prototype.hasNext = function(callback) {
  216.   var self = this;
  218.   // Execute using callback
  219.   if(typeof callback == 'function') {
  220.     if(self.s.currentDoc){
  221.       return callback(null, true);
  222.     } else {
  223.       return nextObject(self, function(err, doc) {
  224.         if (err) return callback(err, null);
  225.         if (!doc) return callback(null, false);
  226.         self.s.currentDoc = doc;
  227.         callback(null, true);
  228.       });
  229.     }
  230.   }
  232.   // Return a Promise
  233.   return new this.s.promiseLibrary(function(resolve, reject) {
  234.     if(self.s.currentDoc){
  235.       resolve(true);
  236.     } else {
  237.       nextObject(self, function(err, doc) {
  238.         if(self.s.state == Cursor.CLOSED || self.isDead()) return resolve(false);
  239.         if(err) return reject(err);
  240.         if(!doc) return resolve(false);
  241.         self.s.currentDoc = doc;
  242.         resolve(true);
  243.       });
  244.     }
  245.   });
  246. }
  248. define.classMethod('hasNext', {callback: true, promise:true});
  250. /**
  251.  * Get the next available document from the cursor, returns null if no more documents are available.
  252.  * @method
  253.  * @param {Cursor~resultCallback} [callback] The result callback.
  254.  * @throws {MongoError}
  255.  * @return {Promise} returns Promise if no callback passed
  256.  */
  257. Cursor.prototype.next = function(callback) {
  258.   var self = this;
  260.   // Execute using callback
  261.   if(typeof callback == 'function') {
  262.     // Return the currentDoc if someone called hasNext first
  263.     if(self.s.currentDoc) {
  264.       var doc = self.s.currentDoc;
  265.       self.s.currentDoc = null;
  266.       return callback(null, doc);
  267.     }
  269.     // Return the next object
  270.     return nextObject(self, callback)
  271.   }
  273.   // Return a Promise
  274.   return new this.s.promiseLibrary(function(resolve, reject) {
  275.     // Return the currentDoc if someone called hasNext first
  276.     if(self.s.currentDoc) {
  277.       var doc = self.s.currentDoc;
  278.       self.s.currentDoc = null;
  279.       return resolve(doc);
  280.     }
  282.     nextObject(self, function(err, r) {
  283.       if(err) return reject(err);
  284.       resolve(r);
  285.     });
  286.   });
  287. }
  289. define.classMethod('next', {callback: true, promise:true});
  291. /**
  292.  * Set the cursor query
  293.  * @method
  294.  * @param {object} filter The filter object used for the cursor.
  295.  * @return {Cursor}
  296.  */
  297. Cursor.prototype.filter = function(filter) {
  298.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  299.   this.s.cmd.query = filter;
  300.   return this;
  301. }
  303. define.classMethod('filter', {callback: false, promise:false, returns: [Cursor]});
  305. /**
  306.  * Set the cursor maxScan
  307.  * @method
  308.  * @param {object} maxScan Constrains the query to only scan the specified number of documents when fulfilling the query
  309.  * @return {Cursor}
  310.  */
  311. Cursor.prototype.maxScan = function(maxScan) {
  312.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  313.   this.s.cmd.maxScan = maxScan;
  314.   return this;
  315. }
  317. define.classMethod('maxScan', {callback: false, promise:false, returns: [Cursor]});
  319. /**
  320.  * Set the cursor hint
  321.  * @method
  322.  * @param {object} hint If specified, then the query system will only consider plans using the hinted index.
  323.  * @return {Cursor}
  324.  */
  325. Cursor.prototype.hint = function(hint) {
  326.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  327.   this.s.cmd.hint = hint;
  328.   return this;
  329. }
  331. define.classMethod('hint', {callback: false, promise:false, returns: [Cursor]});
  333. /**
  334.  * Set the cursor min
  335.  * @method
  336.  * @param {object} min Specify a $min value to specify the inclusive lower bound for a specific index in order to constrain the results of find(). The $min specifies the lower bound for all keys of a specific index in order.
  337.  * @return {Cursor}
  338.  */
  339. Cursor.prototype.min = function(min) {
  340.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  341.   this.s.cmd.min = min;
  342.   return this;
  343. }
  345. define.classMethod('min', {callback: false, promise:false, returns: [Cursor]});
  347. /**
  348.  * Set the cursor max
  349.  * @method
  350.  * @param {object} max Specify a $max value to specify the exclusive upper bound for a specific index in order to constrain the results of find(). The $max specifies the upper bound for all keys of a specific index in order.
  351.  * @return {Cursor}
  352.  */
  353. Cursor.prototype.max = function(max) {
  354.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  355.   this.s.cmd.max = max;
  356.   return this;
  357. }
  359. define.classMethod('max', {callback: false, promise:false, returns: [Cursor]});
  361. /**
  362.  * Set the cursor returnKey
  363.  * @method
  364.  * @param {object} returnKey Only return the index field or fields for the results of the query. If $returnKey is set to true and the query does not use an index to perform the read operation, the returned documents will not contain any fields. Use one of the following forms:
  365.  * @return {Cursor}
  366.  */
  367. Cursor.prototype.returnKey = function(value) {
  368.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  369.   this.s.cmd.returnKey = value;
  370.   return this;
  371. }
  373. define.classMethod('returnKey', {callback: false, promise:false, returns: [Cursor]});
  375. /**
  376.  * Set the cursor showRecordId
  377.  * @method
  378.  * @param {object} showRecordId The $showDiskLoc option has now been deprecated and replaced with the showRecordId field. $showDiskLoc will still be accepted for OP_QUERY stye find.
  379.  * @return {Cursor}
  380.  */
  381. Cursor.prototype.showRecordId = function(value) {
  382.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  383.   this.s.cmd.showDiskLoc = value;
  384.   return this;
  385. }
  387. define.classMethod('showRecordId', {callback: false, promise:false, returns: [Cursor]});
  389. /**
  390.  * Set the cursor snapshot
  391.  * @method
  392.  * @param {object} snapshot The $snapshot operator prevents the cursor from returning a document more than once because an intervening write operation results in a move of the document.
  393.  * @return {Cursor}
  394.  */
  395. Cursor.prototype.snapshot = function(value) {
  396.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  397.   this.s.cmd.snapshot = value;
  398.   return this;
  399. }
  401. define.classMethod('snapshot', {callback: false, promise:false, returns: [Cursor]});
  403. /**
  404.  * Set a node.js specific cursor option
  405.  * @method
  406.  * @param {string} field The cursor option to set ['numberOfRetries', 'tailableRetryInterval'].
  407.  * @param {object} value The field value.
  408.  * @throws {MongoError}
  409.  * @return {Cursor}
  410.  */
  411. Cursor.prototype.setCursorOption = function(field, value) {
  412.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  413.   if(fields.indexOf(field) == -1) throw MongoError.create({message: f("option %s not a supported option %s", field, fields), driver:true });
  414.   this.s[field] = value;
  415.   if(field == 'numberOfRetries')
  416.     this.s.currentNumberOfRetries = value;
  417.   return this;
  418. }
  420. define.classMethod('setCursorOption', {callback: false, promise:false, returns: [Cursor]});
  422. /**
  423.  * Add a cursor flag to the cursor
  424.  * @method
  425.  * @param {string} flag The flag to set, must be one of following ['tailable', 'oplogReplay', 'noCursorTimeout', 'awaitData', 'partial'].
  426.  * @param {boolean} value The flag boolean value.
  427.  * @throws {MongoError}
  428.  * @return {Cursor}
  429.  */
  430. Cursor.prototype.addCursorFlag = function(flag, value) {
  431.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  432.   if(flags.indexOf(flag) == -1) throw MongoError.create({message: f("flag %s not a supported flag %s", flag, flags), driver:true });
  433.   if(typeof value != 'boolean') throw MongoError.create({message: f("flag %s must be a boolean value", flag), driver:true});
  434.   this.s.cmd[flag] = value;
  435.   return this;
  436. }
  438. define.classMethod('addCursorFlag', {callback: false, promise:false, returns: [Cursor]});
  440. /**
  441.  * Add a query modifier to the cursor query
  442.  * @method
  443.  * @param {string} name The query modifier (must start with $, such as $orderby etc)
  444.  * @param {boolean} value The flag boolean value.
  445.  * @throws {MongoError}
  446.  * @return {Cursor}
  447.  */
  448. Cursor.prototype.addQueryModifier = function(name, value) {
  449.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  450.   if(name[0] != '$') throw MongoError.create({message: f("%s is not a valid query modifier"), driver:true});
  451.   // Strip of the $
  452.   var field = name.substr(1);
  453.   // Set on the command
  454.   this.s.cmd[field] = value;
  455.   // Deal with the special case for sort
  456.   if(field == 'orderby') this.s.cmd.sort = this.s.cmd[field];
  457.   return this;
  458. }
  460. define.classMethod('addQueryModifier', {callback: false, promise:false, returns: [Cursor]});
  462. /**
  463.  * Add a comment to the cursor query allowing for tracking the comment in the log.
  464.  * @method
  465.  * @param {string} value The comment attached to this query.
  466.  * @throws {MongoError}
  467.  * @return {Cursor}
  468.  */
  469. Cursor.prototype.comment = function(value) {
  470.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  471.   this.s.cmd.comment = value;
  472.   return this;
  473. }
  475. define.classMethod('comment', {callback: false, promise:false, returns: [Cursor]});
  477. /**
  478.  * Set a maxAwaitTimeMS on a tailing cursor query to allow to customize the timeout value for the option awaitData (Only supported on MongoDB 3.2 or higher, ignored otherwise)
  479.  * @method
  480.  * @param {number} value Number of milliseconds to wait before aborting the tailed query.
  481.  * @throws {MongoError}
  482.  * @return {Cursor}
  483.  */
  484. Cursor.prototype.maxAwaitTimeMS = function(value) {
  485.   if(typeof value != 'number') throw MongoError.create({message: "maxAwaitTimeMS must be a number", driver:true});
  486.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  487.   this.s.cmd.maxAwaitTimeMS = value;
  488.   return this;
  489. }
  491. define.classMethod('maxAwaitTimeMS', {callback: false, promise:false, returns: [Cursor]});
  493. /**
  494.  * Set a maxTimeMS on the cursor query, allowing for hard timeout limits on queries (Only supported on MongoDB 2.6 or higher)
  495.  * @method
  496.  * @param {number} value Number of milliseconds to wait before aborting the query.
  497.  * @throws {MongoError}
  498.  * @return {Cursor}
  499.  */
  500. Cursor.prototype.maxTimeMS = function(value) {
  501.   if(typeof value != 'number') throw MongoError.create({message: "maxTimeMS must be a number", driver:true});
  502.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  503.   this.s.cmd.maxTimeMS = value;
  504.   return this;
  505. }
  507. define.classMethod('maxTimeMS', {callback: false, promise:false, returns: [Cursor]});
  509. Cursor.prototype.maxTimeMs = Cursor.prototype.maxTimeMS;
  511. define.classMethod('maxTimeMs', {callback: false, promise:false, returns: [Cursor]});
  513. /**
  514.  * Sets a field projection for the query.
  515.  * @method
  516.  * @param {object} value The field projection object.
  517.  * @throws {MongoError}
  518.  * @return {Cursor}
  519.  */
  520. Cursor.prototype.project = function(value) {
  521.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  522.   this.s.cmd.fields = value;
  523.   return this;
  524. }
  526. define.classMethod('project', {callback: false, promise:false, returns: [Cursor]});
  528. /**
  529.  * Sets the sort order of the cursor query.
  530.  * @method
  531.  * @param {(string|array|object)} keyOrList The key or keys set for the sort.
  532.  * @param {number} [direction] The direction of the sorting (1 or -1).
  533.  * @throws {MongoError}
  534.  * @return {Cursor}
  535.  */
  536. Cursor.prototype.sort = function(keyOrList, direction) {
  537.   if(this.s.options.tailable) throw MongoError.create({message: "Tailable cursor doesn't support sorting", driver:true});
  538.   if(this.s.state == Cursor.CLOSED || this.s.state == Cursor.OPEN || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  539.   var order = keyOrList;
  541.   // We have an array of arrays, we need to preserve the order of the sort
  542.   // so we will us a Map
  543.   if(Array.isArray(order) && Array.isArray(order[0])) {
  544.     order = new Map(order.map(function(x) {
  545.       var value = [x[0], null];
  546.       if(x[1] == 'asc') {
  547.         value[1] = 1;
  548.       } else if(x[1] == 'desc') {
  549.         value[1] = -1;
  550.       } else if(x[1] == 1 || x[1] == -1) {
  551.         value[1] = x[1];
  552.       } else {
  553.         throw new MongoError("Illegal sort clause, must be of the form [['field1', '(ascending|descending)'], ['field2', '(ascending|descending)']]");
  554.       }
  556.       return value;
  557.     }));
  558.   }
  560.   if(direction != null) {
  561.     order = [[keyOrList, direction]];
  562.   }
  564.   this.s.cmd.sort = order;
  565.   this.sortValue = order;
  566.   return this;
  567. }
  569. define.classMethod('sort', {callback: false, promise:false, returns: [Cursor]});
  571. /**
  572.  * Set the batch size for the cursor.
  573.  * @method
  574.  * @param {number} value The batchSize for the cursor.
  575.  * @throws {MongoError}
  576.  * @return {Cursor}
  577.  */
  578. Cursor.prototype.batchSize = function(value) {
  579.   if(this.s.options.tailable) throw MongoError.create({message: "Tailable cursor doesn't support batchSize", driver:true});
  580.   if(this.s.state == Cursor.CLOSED || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  581.   if(typeof value != 'number') throw MongoError.create({message: "batchSize requires an integer", driver:true});
  582.   this.s.cmd.batchSize = value;
  583.   this.setCursorBatchSize(value);
  584.   return this;
  585. }
  587. define.classMethod('batchSize', {callback: false, promise:false, returns: [Cursor]});
  589. /**
  590.  * Set the collation options for the cursor.
  591.  * @method
  592.  * @param {object} value The cursor collation options (MongoDB 3.4 or higher) settings for update operation (see 3.4 documentation for available fields).
  593.  * @throws {MongoError}
  594.  * @return {Cursor}
  595.  */
  596. Cursor.prototype.collation = function(value) {
  597.   this.s.cmd.collation = value;
  598.   return this;
  599. }
  601. define.classMethod('collation', {callback: false, promise:false, returns: [Cursor]});
  603. /**
  604.  * Set the limit for the cursor.
  605.  * @method
  606.  * @param {number} value The limit for the cursor query.
  607.  * @throws {MongoError}
  608.  * @return {Cursor}
  609.  */
  610. Cursor.prototype.limit = function(value) {
  611.   if(this.s.options.tailable) throw MongoError.create({message: "Tailable cursor doesn't support limit", driver:true});
  612.   if(this.s.state == Cursor.OPEN || this.s.state == Cursor.CLOSED || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  613.   if(typeof value != 'number') throw MongoError.create({message: "limit requires an integer", driver:true});
  614.   this.s.cmd.limit = value;
  615.   // this.cursorLimit = value;
  616.   this.setCursorLimit(value);
  617.   return this;
  618. }
  620. define.classMethod('limit', {callback: false, promise:false, returns: [Cursor]});
  622. /**
  623.  * Set the skip for the cursor.
  624.  * @method
  625.  * @param {number} value The skip for the cursor query.
  626.  * @throws {MongoError}
  627.  * @return {Cursor}
  628.  */
  629. Cursor.prototype.skip = function(value) {
  630.   if(this.s.options.tailable) throw MongoError.create({message: "Tailable cursor doesn't support skip", driver:true});
  631.   if(this.s.state == Cursor.OPEN || this.s.state == Cursor.CLOSED || this.isDead()) throw MongoError.create({message: "Cursor is closed", driver:true});
  632.   if(typeof value != 'number') throw MongoError.create({message: "skip requires an integer", driver:true});
  633.   this.s.cmd.skip = value;
  634.   this.setCursorSkip(value);
  635.   return this;
  636. }
  638. define.classMethod('skip', {callback: false, promise:false, returns: [Cursor]});
  640. /**
  641.  * The callback format for results
  642.  * @callback Cursor~resultCallback
  643.  * @param {MongoError} error An error instance representing the error during the execution.
  644.  * @param {(object|null|boolean)} result The result object if the command was executed successfully.
  645.  */
  647. /**
  648.  * Clone the cursor
  649.  * @function external:CoreCursor#clone
  650.  * @return {Cursor}
  651.  */
  653. /**
  654.  * Resets the cursor
  655.  * @function external:CoreCursor#rewind
  656.  * @return {null}
  657.  */
  659. /**
  660.  * Get the next available document from the cursor, returns null if no more documents are available.
  661.  * @method
  662.  * @param {Cursor~resultCallback} [callback] The result callback.
  663.  * @throws {MongoError}
  664.  * @deprecated
  665.  * @return {Promise} returns Promise if no callback passed
  666.  */
  667. Cursor.prototype.nextObject = Cursor.prototype.next;
  669. var nextObject = function(self, callback) {
  670.   if(self.s.state == Cursor.CLOSED || self.isDead && self.isDead()) return handleCallback(callback, MongoError.create({message: "Cursor is closed", driver:true}));
  671.   if(self.s.state == Cursor.INIT && self.s.cmd.sort) {
  672.     try {
  673.       self.s.cmd.sort = formattedOrderClause(self.s.cmd.sort);
  674.     } catch(err) {
  675.       return handleCallback(callback, err);
  676.     }
  677.   }
  679.   // Get the next object
  680.   self._next(function(err, doc) {
  681.     self.s.state = Cursor.OPEN;
  682.     if(err) return handleCallback(callback, err);
  683.     handleCallback(callback, null, doc);
  684.   });
  685. }
  687. define.classMethod('nextObject', {callback: true, promise:true});
  689. // Trampoline emptying the number of retrieved items
  690. // without incurring a nextTick operation
  691. var loop = function(self, callback) {
  692.   // No more items we are done
  693.   if(self.bufferedCount() == 0) return;
  694.   // Get the next document
  695.   self._next(callback);
  696.   // Loop
  697.   return loop;
  698. }
  700. Cursor.prototype.next = Cursor.prototype.nextObject;
  702. define.classMethod('next', {callback: true, promise:true});
  704. /**
  705.  * Iterates over all the documents for this cursor. As with **{cursor.toArray}**,
  706.  * not all of the elements will be iterated if this cursor had been previously accessed.
  707.  * In that case, **{cursor.rewind}** can be used to reset the cursor. However, unlike
  708.  * **{cursor.toArray}**, the cursor will only hold a maximum of batch size elements
  709.  * at any given time if batch size is specified. Otherwise, the caller is responsible
  710.  * for making sure that the entire result can fit the memory.
  711.  * @method
  712.  * @deprecated
  713.  * @param {Cursor~resultCallback} callback The result callback.
  714.  * @throws {MongoError}
  715.  * @return {null}
  716.  */
  717. Cursor.prototype.each = function(callback) {
  718.   // Rewind cursor state
  719.   this.rewind();
  720.   // Set current cursor to INIT
  721.   this.s.state = Cursor.INIT;
  722.   // Run the query
  723.   _each(this, callback);
  724. };
  726. define.classMethod('each', {callback: true, promise:false});
  728. // Run the each loop
  729. var _each = function(self, callback) {
  730.   if(!callback) throw MongoError.create({message: 'callback is mandatory', driver:true});
  731.   if(self.isNotified()) return;
  732.   if(self.s.state == Cursor.CLOSED || self.isDead()) {
  733.     return handleCallback(callback, MongoError.create({message: "Cursor is closed", driver:true}));
  734.   }
  736.   if(self.s.state == Cursor.INIT) self.s.state = Cursor.OPEN;
  738.   // Define function to avoid global scope escape
  739.   var fn = null;
  740.   // Trampoline all the entries
  741.   if(self.bufferedCount() > 0) {
  742.     while(fn = loop(self, callback)) fn(self, callback);
  743.     _each(self, callback);
  744.   } else {
  745.     self.next(function(err, item) {
  746.       if(err) return handleCallback(callback, err);
  747.       if(item == null) {
  748.         self.s.state = Cursor.CLOSED;
  749.         return handleCallback(callback, null, null);
  750.       }
  752.       if(handleCallback(callback, null, item) == false) return;
  753.       _each(self, callback);
  754.     })
  755.   }
  756. }
  758. /**
  759.  * The callback format for the forEach iterator method
  760.  * @callback Cursor~iteratorCallback
  761.  * @param {Object} doc An emitted document for the iterator
  762.  */
  764. /**
  765.  * The callback error format for the forEach iterator method
  766.  * @callback Cursor~endCallback
  767.  * @param {MongoError} error An error instance representing the error during the execution.
  768.  */
  770. /**
  771.  * Iterates over all the documents for this cursor using the iterator, callback pattern.
  772.  * @method
  773.  * @param {Cursor~iteratorCallback} iterator The iteration callback.
  774.  * @param {Cursor~endCallback} callback The end callback.
  775.  * @throws {MongoError}
  776.  * @return {null}
  777.  */
  778. Cursor.prototype.forEach = function(iterator, callback) {
  779.   this.each(function(err, doc){
  780.     if(err) { callback(err); return false; }
  781.     if(doc != null) { iterator(doc); return true; }
  782.     if(doc == null && callback) {
  783.       var internalCallback = callback;
  784.       callback = null;
  785.       internalCallback(null);
  786.       return false;
  787.     }
  788.   });
  789. }
  791. define.classMethod('forEach', {callback: true, promise:false});
  793. /**
  794.  * Set the ReadPreference for the cursor.
  795.  * @method
  796.  * @param {(string|ReadPreference)} readPreference The new read preference for the cursor.
  797.  * @throws {MongoError}
  798.  * @return {Cursor}
  799.  */
  800. Cursor.prototype.setReadPreference = function(r) {
  801.   if(this.s.state != Cursor.INIT) throw MongoError.create({message: 'cannot change cursor readPreference after cursor has been accessed', driver:true});
  802.   if(r instanceof ReadPreference) {
  803.     this.s.options.readPreference = new CoreReadPreference(r.mode, r.tags, {maxStalenessSeconds: r.maxStalenessSeconds});
  804.   } else if(typeof r == 'string'){
  805.     this.s.options.readPreference = new CoreReadPreference(r);
  806.   } else if(r instanceof CoreReadPreference) {
  807.     this.s.options.readPreference = r;
  808.   }
  810.   return this;
  811. }
  813. define.classMethod('setReadPreference', {callback: false, promise:false, returns: [Cursor]});
  815. /**
  816.  * The callback format for results
  817.  * @callback Cursor~toArrayResultCallback
  818.  * @param {MongoError} error An error instance representing the error during the execution.
  819.  * @param {object[]} documents All the documents the satisfy the cursor.
  820.  */
  822. /**
  823.  * Returns an array of documents. The caller is responsible for making sure that there
  824.  * is enough memory to store the results. Note that the array only contain partial
  825.  * results when this cursor had been previously accessed. In that case,
  826.  * cursor.rewind() can be used to reset the cursor.
  827.  * @method
  828.  * @param {Cursor~toArrayResultCallback} [callback] The result callback.
  829.  * @throws {MongoError}
  830.  * @return {Promise} returns Promise if no callback passed
  831.  */
  832. Cursor.prototype.toArray = function(callback) {
  833.   var self = this;
  834.   if(self.s.options.tailable) throw MongoError.create({message: 'Tailable cursor cannot be converted to array', driver:true});
  836.   // Execute using callback
  837.   if(typeof callback == 'function') return toArray(self, callback);
  839.   // Return a Promise
  840.   return new this.s.promiseLibrary(function(resolve, reject) {
  841.     toArray(self, function(err, r) {
  842.       if(err) return reject(err);
  843.       resolve(r);
  844.     });
  845.   });
  846. }
  848. var toArray = function(self, callback) {
  849.   var items = [];
  851.   // Reset cursor
  852.   self.rewind();
  853.   self.s.state = Cursor.INIT;
  855.   // Fetch all the documents
  856.   var fetchDocs = function() {
  857.     self._next(function(err, doc) {
  858.       if(err) return handleCallback(callback, err);
  859.       if(doc == null) {
  860.         self.s.state = Cursor.CLOSED;
  861.         return handleCallback(callback, null, items);
  862.       }
  864.       // Add doc to items
  865.       items.push(doc)
  867.       // Get all buffered objects
  868.       if(self.bufferedCount() > 0) {
  869.         var docs = self.readBufferedDocuments(self.bufferedCount())
  871.         // Transform the doc if transform method added
  872.         if(self.s.transforms && typeof self.s.transforms.doc == 'function') {
  873.           docs = docs.map(self.s.transforms.doc);
  874.         }
  876.         push.apply(items, docs);
  877.       }
  879.       // Attempt a fetch
  880.       fetchDocs();
  881.     })
  882.   }
  884.   fetchDocs();
  885. }
  887. define.classMethod('toArray', {callback: true, promise:true});
  889. /**
  890.  * The callback format for results
  891.  * @callback Cursor~countResultCallback
  892.  * @param {MongoError} error An error instance representing the error during the execution.
  893.  * @param {number} count The count of documents.
  894.  */
  896. /**
  897.  * Get the count of documents for this cursor
  898.  * @method
  899.  * @param {boolean} [applySkipLimit=true] Should the count command apply limit and skip settings on the cursor or in the passed in options.
  900.  * @param {object} [options=null] Optional settings.
  901.  * @param {number} [options.skip=null] The number of documents to skip.
  902.  * @param {number} [options.limit=null] The maximum amounts to count before aborting.
  903.  * @param {number} [options.maxTimeMS=null] Number of milliseconds to wait before aborting the query.
  904.  * @param {string} [options.hint=null] An index name hint for the query.
  905.  * @param {(ReadPreference|string)} [options.readPreference=null] The preferred read preference (ReadPreference.PRIMARY, ReadPreference.PRIMARY_PREFERRED, ReadPreference.SECONDARY, ReadPreference.SECONDARY_PREFERRED, ReadPreference.NEAREST).
  906.  * @param {Cursor~countResultCallback} [callback] The result callback.
  907.  * @return {Promise} returns Promise if no callback passed
  908.  */
  909. Cursor.prototype.count = function(applySkipLimit, opts, callback) {
  910.   var self = this;
  911.   if(self.s.cmd.query == null) throw MongoError.create({message: "count can only be used with find command", driver:true});
  912.   if(typeof opts == 'function') callback = opts, opts = {};
  913.   opts = opts || {};
  915.   // Execute using callback
  916.   if(typeof callback == 'function') return count(self, applySkipLimit, opts, callback);
  918.   // Return a Promise
  919.   return new this.s.promiseLibrary(function(resolve, reject) {
  920.     count(self, applySkipLimit, opts, function(err, r) {
  921.       if(err) return reject(err);
  922.       resolve(r);
  923.     });
  924.   });
  925. };
  927. var count = function(self, applySkipLimit, opts, callback) {
  928.   if(typeof applySkipLimit == 'function') {
  929.     callback = applySkipLimit;
  930.     applySkipLimit = true;
  931.   }
  933.   if(applySkipLimit) {
  934.     if(typeof self.cursorSkip() == 'number') opts.skip = self.cursorSkip();
  935.     if(typeof self.cursorLimit() == 'number') opts.limit = self.cursorLimit();
  936.   }
  938.   // Command
  939.   var delimiter = self.s.ns.indexOf('.');
  941.   var command = {
  942.     'count': self.s.ns.substr(delimiter+1), 'query': self.s.cmd.query
  943.   }
  945.   // Apply a readConcern if set
  946.   if(self.s.cmd.readConcern) {
  947.     command.readConcern = self.s.cmd.readConcern;
  948.   }
  950.   // Apply a hint if set
  951.   if(self.s.cmd.hint) {
  952.     command.hint = self.s.cmd.hint;
  953.   }
  955.   if(typeof opts.maxTimeMS == 'number') {
  956.     command.maxTimeMS = opts.maxTimeMS;
  957.   } else if(self.s.cmd && typeof self.s.cmd.maxTimeMS == 'number') {
  958.     command.maxTimeMS = self.s.cmd.maxTimeMS;
  959.   }
  961.   // Merge in any options
  962.   if(opts.skip) command.skip = opts.skip;
  963.   if(opts.limit) command.limit = opts.limit;
  964.   if(self.s.options.hint) command.hint = self.s.options.hint;
  966.   // Set cursor server to the same as the topology
  967.   self.server = self.topology;
  969.   // Execute the command
  970.   self.topology.command(f("%s.$cmd", self.s.ns.substr(0, delimiter))
  971.     , command, function(err, result) {
  972.       callback(err, result ? result.result.n : null)
  973.     }, self.options);
  974. }
  976. define.classMethod('count', {callback: true, promise:true});
  978. /**
  979.  * Close the cursor, sending a KillCursor command and emitting close.
  980.  * @method
  981.  * @param {Cursor~resultCallback} [callback] The result callback.
  982.  * @return {Promise} returns Promise if no callback passed
  983.  */
  984. Cursor.prototype.close = function(callback) {
  985.   this.s.state = Cursor.CLOSED;
  986.   // Kill the cursor
  987.   this.kill();
  988.   // Emit the close event for the cursor
  989.   this.emit('close');
  990.   // Callback if provided
  991.   if(typeof callback == 'function') return handleCallback(callback, null, this);
  992.   // Return a Promise
  993.   return new this.s.promiseLibrary(function(resolve) {
  994.     resolve();
  995.   });
  996. }
  998. define.classMethod('close', {callback: true, promise:true});
  1000. /**
  1001.  * Map all documents using the provided function
  1002.  * @method
  1003.  * @param {function} [transform] The mapping transformation method.
  1004.  * @return {Cursor}
  1005.  */
  1006. Cursor.prototype.map = function(transform) {
  1007.   if(this.cursorState.transforms && this.cursorState.transforms.doc) {
  1008.     var oldTransform = this.cursorState.transforms.doc;
  1009.     this.cursorState.transforms.doc = function (doc) { return transform(oldTransform(doc)); };
  1010.   } else {
  1011.     this.cursorState.transforms = { doc: transform };
  1012.   }
  1013.   return this;
  1014. }
  1016. define.classMethod('map', {callback: false, promise:false, returns: [Cursor]});
  1018. /**
  1019.  * Is the cursor closed
  1020.  * @method
  1021.  * @return {boolean}
  1022.  */
  1023. Cursor.prototype.isClosed = function() {
  1024.   return this.isDead();
  1025. }
  1027. define.classMethod('isClosed', {callback: false, promise:false, returns: [Boolean]});
  1029. Cursor.prototype.destroy = function(err) {
  1030.   if(err) this.emit('error', err);
  1031.   this.pause();
  1032.   this.close();
  1033. }
  1035. define.classMethod('destroy', {callback: false, promise:false});
  1037. /**
  1038.  * Return a modified Readable stream including a possible transform method.
  1039.  * @method
  1040.  * @param {object} [options=null] Optional settings.
  1041.  * @param {function} [options.transform=null] A transformation method applied to each document emitted by the stream.
  1042.  * @return {Cursor}
  1043.  */
  1044. Cursor.prototype.stream = function(options) {
  1045.   this.s.streamOptions = options || {};
  1046.   return this;
  1047. }
  1049. define.classMethod('stream', {callback: false, promise:false, returns: [Cursor]});
  1051. /**
  1052.  * Execute the explain for the cursor
  1053.  * @method
  1054.  * @param {Cursor~resultCallback} [callback] The result callback.
  1055.  * @return {Promise} returns Promise if no callback passed
  1056.  */
  1057. Cursor.prototype.explain = function(callback) {
  1058.   var self = this;
  1059.   this.s.cmd.explain = true;
  1061.   // Do we have a readConcern
  1062.   if(this.s.cmd.readConcern) {
  1063.     delete this.s.cmd['readConcern'];
  1064.   }
  1066.   // Execute using callback
  1067.   if(typeof callback == 'function') return this._next(callback);
  1069.   // Return a Promise
  1070.   return new this.s.promiseLibrary(function(resolve, reject) {
  1071.     self._next(function(err, r) {
  1072.       if(err) return reject(err);
  1073.       resolve(r);
  1074.     });
  1075.   });
  1076. }
  1078. define.classMethod('explain', {callback: true, promise:true});
  1080. Cursor.prototype._read = function() {
  1081.   var self = this;
  1082.   if(self.s.state == Cursor.CLOSED || self.isDead()) {
  1083.     return self.push(null);
  1084.   }
  1086.   // Get the next item
  1087.   self.nextObject(function(err, result) {
  1088.     if(err) {
  1089.       if(self.listeners('error') && self.listeners('error').length > 0) {
  1090.         self.emit('error', err);
  1091.       }
  1092.       if(!self.isDead()) self.close();
  1094.       // Emit end event
  1095.       self.emit('end');
  1096.       return self.emit('finish');
  1097.     }
  1099.     // If we provided a transformation method
  1100.     if(typeof self.s.streamOptions.transform == 'function' && result != null) {
  1101.       return self.push(self.s.streamOptions.transform(result));
  1102.     }
  1104.     // If we provided a map function
  1105.     if(self.cursorState.transforms && typeof self.cursorState.transforms.doc == 'function' && result != null) {
  1106.       return self.push(self.cursorState.transforms.doc(result));
  1107.     }
  1109.     // Return the result
  1110.     self.push(result);
  1111.   });
  1112. }
  1114. Object.defineProperty(Cursor.prototype, 'readPreference', {
  1115.   enumerable:true,
  1116.   get: function() {
  1117.     if (!this || !this.s) {
  1118.       return null;
  1119.     }
  1121.     return this.s.options.readPreference;
  1122.   }
  1123. });
  1125. Object.defineProperty(Cursor.prototype, 'namespace', {
  1126.   enumerable: true,
  1127.   get: function() {
  1128.     if (!this || !this.s) {
  1129.       return null;
  1130.     }
  1132.     // TODO: refactor this logic into core
  1133.     var ns = this.s.ns || '';
  1134.     var firstDot = ns.indexOf('.');
  1135.     if (firstDot < 0) {
  1136.       return {
  1137.         database: this.s.ns,
  1138.         collection: ''
  1139.       };
  1140.     }
  1141.     return {
  1142.       database: ns.substr(0, firstDot),
  1143.       collection: ns.substr(firstDot + 1)
  1144.     };
  1145.   }
  1146. });
  1148. /**
  1149.  * 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.
  1150.  * @function external:Readable#read
  1151.  * @param {number} size Optional argument to specify how much data to read.
  1152.  * @return {(String | Buffer | null)}
  1153.  */
  1155. /**
  1156.  * Call this function to cause the stream to return strings of the specified encoding instead of Buffer objects.
  1157.  * @function external:Readable#setEncoding
  1158.  * @param {string} encoding The encoding to use.
  1159.  * @return {null}
  1160.  */
  1162. /**
  1163.  * This method will cause the readable stream to resume emitting data events.
  1164.  * @function external:Readable#resume
  1165.  * @return {null}
  1166.  */
  1168. /**
  1169.  * 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.
  1170.  * @function external:Readable#pause
  1171.  * @return {null}
  1172.  */
  1174. /**
  1175.  * 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.
  1176.  * @function external:Readable#pipe
  1177.  * @param {Writable} destination The destination for writing data
  1178.  * @param {object} [options] Pipe options
  1179.  * @return {null}
  1180.  */
  1182. /**
  1183.  * This method will remove the hooks set up for a previous pipe() call.
  1184.  * @function external:Readable#unpipe
  1185.  * @param {Writable} [destination] The destination for writing data
  1186.  * @return {null}
  1187.  */
  1189. /**
  1190.  * 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.
  1191.  * @function external:Readable#unshift
  1192.  * @param {(Buffer|string)} chunk Chunk of data to unshift onto the read queue.
  1193.  * @return {null}
  1194.  */
  1196. /**
  1197.  * 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.)
  1198.  * @function external:Readable#wrap
  1199.  * @param {Stream} stream An "old style" readable stream.
  1200.  * @return {null}
  1201.  */
  1203. Cursor.INIT = 0;
  1204. Cursor.OPEN = 1;
  1205. Cursor.CLOSED = 2;
  1206. Cursor.GET_MORE = 3;
  1208. module.exports = Cursor;