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					62 lines
				
				1.1 KiB
			
		
		
			
		
	
	
					62 lines
				
				1.1 KiB
			| 
											3 years ago
										 | 'use strict'; | ||
|  | 
 | ||
|  | /*! | ||
|  |  * Module dependencies. | ||
|  |  */ | ||
|  | 
 | ||
|  | const EventEmitter = require('events').EventEmitter; | ||
|  | 
 | ||
|  | /*! | ||
|  |  * ignore | ||
|  |  */ | ||
|  | 
 | ||
|  | class ChangeStream extends EventEmitter { | ||
|  |   constructor(changeStreamThunk, pipeline, options) { | ||
|  |     super(); | ||
|  | 
 | ||
|  |     this.driverChangeStream = null; | ||
|  |     this.closed = false; | ||
|  |     this.pipeline = pipeline; | ||
|  |     this.options = options; | ||
|  | 
 | ||
|  |     // This wrapper is necessary because of buffering.
 | ||
|  |     changeStreamThunk((err, driverChangeStream) => { | ||
|  |       if (err != null) { | ||
|  |         this.emit('error', err); | ||
|  |         return; | ||
|  |       } | ||
|  | 
 | ||
|  |       this.driverChangeStream = driverChangeStream; | ||
|  |       this._bindEvents(); | ||
|  |       this.emit('ready'); | ||
|  |     }); | ||
|  |   } | ||
|  | 
 | ||
|  |   _bindEvents() { | ||
|  |     this.driverChangeStream.on('close', () => { | ||
|  |       this.closed = true; | ||
|  |     }); | ||
|  | 
 | ||
|  |     ['close', 'change', 'end', 'error'].forEach(ev => { | ||
|  |       this.driverChangeStream.on(ev, data => this.emit(ev, data)); | ||
|  |     }); | ||
|  |   } | ||
|  | 
 | ||
|  |   _queue(cb) { | ||
|  |     this.once('ready', () => cb()); | ||
|  |   } | ||
|  | 
 | ||
|  |   close() { | ||
|  |     this.closed = true; | ||
|  |     if (this.driverChangeStream) { | ||
|  |       this.driverChangeStream.close(); | ||
|  |     } | ||
|  |   } | ||
|  | } | ||
|  | 
 | ||
|  | /*! | ||
|  |  * ignore | ||
|  |  */ | ||
|  | 
 | ||
|  | module.exports = ChangeStream; |