'use strict';
const inherits = require('util').inherits;
const ReadPreference = require('mongodb-core').ReadPreference;
const MongoError = require('mongodb-core').MongoError;
const Readable = require('stream').Readable;
const CoreCursor = require('./cursor');
const SUPPORTS = require('./utils').SUPPORTS;
/**
* @fileOverview The **CommandCursor** class is an internal class that embodies a
* generalized cursor based on a MongoDB command allowing for iteration over the
* results returned. It supports one by one document iteration, conversion to an
* array or can be iterated as a Node 0.10.X or higher stream
*
* **CommandCursor Cannot directly be instantiated**
* @example
* const MongoClient = require('mongodb').MongoClient;
* const test = require('assert');
* // Connection url
* const url = 'mongodb://localhost:27017';
* // Database Name
* const dbName = 'test';
* // Connect using MongoClient
* MongoClient.connect(url, function(err, client) {
* // Create a collection we want to drop later
* const col = client.db(dbName).collection('listCollectionsExample1');
* // Insert a bunch of documents
* col.insert([{a:1, b:1}
* , {a:2, b:2}, {a:3, b:3}
* , {a:4, b:4}], {w:1}, function(err, result) {
* test.equal(null, err);
* // List the database collections available
* db.listCollections().toArray(function(err, items) {
* test.equal(null, err);
* client.close();
* });
* });
* });
*/
/**
* Namespace provided by the browser.
* @external Readable
*/
/**
* Creates a new Command Cursor instance (INTERNAL TYPE, do not instantiate directly)
* @class CommandCursor
* @extends external:Readable
* @fires CommandCursor#data
* @fires CommandCursor#end
* @fires CommandCursor#close
* @fires CommandCursor#readable
* @return {CommandCursor} an CommandCursor instance.
*/
var CommandCursor = function(bson, ns, cmd, options, topology, topologyOptions) {
CoreCursor.apply(this, Array.prototype.slice.call(arguments, 0));
var state = CommandCursor.INIT;
var streamOptions = {};
// MaxTimeMS
var maxTimeMS = null;
// Get the promiseLibrary
var promiseLibrary = options.promiseLibrary || Promise;
// Set up
Readable.call(this, { objectMode: true });
// Internal state
this.s = {
// MaxTimeMS
maxTimeMS: maxTimeMS,
// State
state: state,
// Stream options
streamOptions: streamOptions,
// BSON
bson: bson,
// Namespace
ns: ns,
// Command
cmd: cmd,
// Options
options: options,
// Topology
topology: topology,
// Topology Options
topologyOptions: topologyOptions,
// Promise library
promiseLibrary: promiseLibrary,
// Optional ClientSession
session: options.session
};
};
/**
* CommandCursor stream data event, fired for each document in the cursor.
*
* @event CommandCursor#data
* @type {object}
*/
/**
* CommandCursor stream end event
*
* @event CommandCursor#end
* @type {null}
*/
/**
* CommandCursor stream close event
*
* @event CommandCursor#close
* @type {null}
*/
/**
* CommandCursor stream readable event
*
* @event CommandCursor#readable
* @type {null}
*/
// Inherit from Readable
inherits(CommandCursor, Readable);
// Set the methods to inherit from prototype
var methodsToInherit = [
'_next',
'next',
'hasNext',
'each',
'forEach',
'toArray',
'rewind',
'bufferedCount',
'readBufferedDocuments',
'close',
'isClosed',
'kill',
'setCursorBatchSize',
'_find',
'_getmore',
'_killcursor',
'isDead',
'explain',
'isNotified',
'isKilled',
'_endSession',
'_initImplicitSession'
];
// Only inherit the types we need
for (var i = 0; i < methodsToInherit.length; i++) {
CommandCursor.prototype[methodsToInherit[i]] = CoreCursor.prototype[methodsToInherit[i]];
}
if (SUPPORTS.ASYNC_ITERATOR) {
CommandCursor.prototype[Symbol.asyncIterator] = require('./async/async_iterator').asyncIterator;
}
/**
* Set the ReadPreference for the cursor.
* @method
* @param {(string|ReadPreference)} readPreference The new read preference for the cursor.
* @throws {MongoError}
* @return {Cursor}
*/
CommandCursor.prototype.setReadPreference = function(readPreference) {
if (this.s.state === CommandCursor.CLOSED || this.isDead()) {
throw MongoError.create({ message: 'Cursor is closed', driver: true });
}
if (this.s.state !== CommandCursor.INIT) {
throw MongoError.create({
message: 'cannot change cursor readPreference after cursor has been accessed',
driver: true
});
}
if (readPreference instanceof ReadPreference) {
this.s.options.readPreference = readPreference;
} else if (typeof readPreference === 'string') {
this.s.options.readPreference = new ReadPreference(readPreference);
} else {
throw new TypeError('Invalid read preference: ' + readPreference);
}
return this;
};
/**
* Set the batch size for the cursor.
* @method
* @param {number} value The batchSize for the cursor.
* @throws {MongoError}
* @return {CommandCursor}
*/
CommandCursor.prototype.batchSize = function(value) {
if (this.s.state === CommandCursor.CLOSED || this.isDead())
throw MongoError.create({ message: 'Cursor is closed', driver: true });
if (typeof value !== 'number')
throw MongoError.create({ message: 'batchSize requires an integer', driver: true });
if (this.s.cmd.cursor) this.s.cmd.cursor.batchSize = value;
this.setCursorBatchSize(value);
return this;
};
/**
* Add a maxTimeMS stage to the aggregation pipeline
* @method
* @param {number} value The state maxTimeMS value.
* @return {CommandCursor}
*/
CommandCursor.prototype.maxTimeMS = function(value) {
if (this.s.topology.lastIsMaster().minWireVersion > 2) {
this.s.cmd.maxTimeMS = value;
}
return this;
};
/**
* Return the cursor logger
* @method
* @return {Logger} return the cursor logger
* @ignore
*/
CommandCursor.prototype.getLogger = function() {
return this.logger;
};
CommandCursor.prototype.get = CommandCursor.prototype.toArray;
/**
* Get the next available document from the cursor, returns null if no more documents are available.
* @function CommandCursor.prototype.next
* @param {CommandCursor~resultCallback} [callback] The result callback.
* @throws {MongoError}
* @return {Promise} returns Promise if no callback passed
*/
/**
* Check if there is any document still available in the cursor
* @function CommandCursor.prototype.hasNext
* @param {CommandCursor~resultCallback} [callback] The result callback.
* @throws {MongoError}
* @return {Promise} returns Promise if no callback passed
*/
/**
* The callback format for results
* @callback CommandCursor~toArrayResultCallback
* @param {MongoError} error An error instance representing the error during the execution.
* @param {object[]} documents All the documents the satisfy the cursor.
*/
/**
* Returns an array of documents. The caller is responsible for making sure that there
* is enough memory to store the results. Note that the array only contain partial
* results when this cursor had been previously accessed.
* @method CommandCursor.prototype.toArray
* @param {CommandCursor~toArrayResultCallback} [callback] The result callback.
* @throws {MongoError}
* @return {Promise} returns Promise if no callback passed
*/
/**
* The callback format for results
* @callback CommandCursor~resultCallback
* @param {MongoError} error An error instance representing the error during the execution.
* @param {(object|null)} result The result object if the command was executed successfully.
*/
/**
* Iterates over all the documents for this cursor. As with **{cursor.toArray}**,
* not all of the elements will be iterated if this cursor had been previously accessed.
* In that case, **{cursor.rewind}** can be used to reset the cursor. However, unlike
* **{cursor.toArray}**, the cursor will only hold a maximum of batch size elements
* at any given time if batch size is specified. Otherwise, the caller is responsible
* for making sure that the entire result can fit the memory.
* @method CommandCursor.prototype.each
* @param {CommandCursor~resultCallback} callback The result callback.
* @throws {MongoError}
* @return {null}
*/
/**
* Close the cursor, sending a KillCursor command and emitting close.
* @method CommandCursor.prototype.close
* @param {CommandCursor~resultCallback} [callback] The result callback.
* @return {Promise} returns Promise if no callback passed
*/
/**
* Is the cursor closed
* @method CommandCursor.prototype.isClosed
* @return {boolean}
*/
/**
* Clone the cursor
* @function CommandCursor.prototype.clone
* @return {CommandCursor}
*/
/**
* Resets the cursor
* @function CommandCursor.prototype.rewind
* @return {CommandCursor}
*/
/**
* The callback format for the forEach iterator method
* @callback CommandCursor~iteratorCallback
* @param {Object} doc An emitted document for the iterator
*/
/**
* The callback error format for the forEach iterator method
* @callback CommandCursor~endCallback
* @param {MongoError} error An error instance representing the error during the execution.
*/
/*
* Iterates over all the documents for this cursor using the iterator, callback pattern.
* @method CommandCursor.prototype.forEach
* @param {CommandCursor~iteratorCallback} iterator The iteration callback.
* @param {CommandCursor~endCallback} callback The end callback.
* @throws {MongoError}
* @return {null}
*/
CommandCursor.INIT = 0;
CommandCursor.OPEN = 1;
CommandCursor.CLOSED = 2;
module.exports = CommandCursor;