yichael_nodejssocketserver/node_modules/nodejs-websocket/OutStream.js

/**
 * @file Simple wrapper for stream.Writable, used for sending binary data
 */
'use strict'

var util = require('util'),
	stream = require('stream'),
	frame = require('./frame')

/**
 * @class Represents the writable stream for binary frames
 * @param {Connection} connection
 * @param {number} minSize
 */
function OutStream(connection, minSize) {
	var that = this
	this.connection = connection
	this.minSize = minSize
	this.buffer = Buffer.alloc(0)
	this.hasSent = false // Indicates if any frame has been sent yet
	stream.Writable.call(this)
	this.on('finish', function () {
		if (that.connection.readyState === that.connection.OPEN) {
			// Ignore if not connected anymore
			that.connection.socket.write(frame.createBinaryFrame(that.buffer, !that.connection.server, !that.hasSent, true))
		}
		that.connection.outStream = null
	})
}

module.exports = OutStream


util.inherits(OutStream, stream.Writable)

/**
 * @param {Buffer} chunk
 * @param {string} encoding
 * @param {Function} callback
 * @private
 */
OutStream.prototype._write = function (chunk, encoding, callback) {
	var frameBuffer
	this.buffer = Buffer.concat([this.buffer, chunk], this.buffer.length + chunk.length)
	if (this.buffer.length >= this.minSize) {
		if (this.connection.readyState === this.connection.OPEN) {
			// Ignore if not connected anymore
			frameBuffer = frame.createBinaryFrame(this.buffer, !this.connection.server, !this.hasSent, false)
			this.connection.socket.write(frameBuffer, encoding, callback)
		}
		this.buffer = Buffer.alloc(0)
		this.hasSent = true
		if (this.connection.readyState !== this.connection.OPEN) {
			callback()
		}
	} else {
		callback()
	}
}