478 lines
12 KiB
JavaScript
478 lines
12 KiB
JavaScript
/* eslint no-unused-vars: ["error", { "varsIgnorePattern": "^Duplex" }] */
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'use strict';
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const { Duplex } = require('stream');
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const { randomFillSync } = require('crypto');
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const PerMessageDeflate = require('./permessage-deflate');
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const { EMPTY_BUFFER } = require('./constants');
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const { isValidStatusCode } = require('./validation');
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const { mask: applyMask, toBuffer } = require('./buffer-util');
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const kByteLength = Symbol('kByteLength');
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const maskBuffer = Buffer.alloc(4);
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/**
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* HyBi Sender implementation.
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*/
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class Sender {
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/**
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* Creates a Sender instance.
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*
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* @param {Duplex} socket The connection socket
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* @param {Object} [extensions] An object containing the negotiated extensions
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* @param {Function} [generateMask] The function used to generate the masking
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* key
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*/
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constructor(socket, extensions, generateMask) {
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this._extensions = extensions || {};
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if (generateMask) {
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this._generateMask = generateMask;
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this._maskBuffer = Buffer.alloc(4);
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}
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this._socket = socket;
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this._firstFragment = true;
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this._compress = false;
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this._bufferedBytes = 0;
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this._deflating = false;
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this._queue = [];
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}
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/**
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* Frames a piece of data according to the HyBi WebSocket protocol.
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*
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* @param {(Buffer|String)} data The data to frame
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* @param {Object} options Options object
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* @param {Boolean} [options.fin=false] Specifies whether or not to set the
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* FIN bit
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* @param {Function} [options.generateMask] The function used to generate the
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* masking key
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* @param {Boolean} [options.mask=false] Specifies whether or not to mask
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* `data`
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* @param {Buffer} [options.maskBuffer] The buffer used to store the masking
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* key
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* @param {Number} options.opcode The opcode
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* @param {Boolean} [options.readOnly=false] Specifies whether `data` can be
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* modified
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* @param {Boolean} [options.rsv1=false] Specifies whether or not to set the
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* RSV1 bit
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* @return {(Buffer|String)[]} The framed data
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* @public
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*/
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static frame(data, options) {
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let mask;
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let merge = false;
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let offset = 2;
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let skipMasking = false;
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if (options.mask) {
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mask = options.maskBuffer || maskBuffer;
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if (options.generateMask) {
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options.generateMask(mask);
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} else {
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randomFillSync(mask, 0, 4);
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}
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skipMasking = (mask[0] | mask[1] | mask[2] | mask[3]) === 0;
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offset = 6;
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}
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let dataLength;
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if (typeof data === 'string') {
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if (
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(!options.mask || skipMasking) &&
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options[kByteLength] !== undefined
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) {
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dataLength = options[kByteLength];
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} else {
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data = Buffer.from(data);
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dataLength = data.length;
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}
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} else {
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dataLength = data.length;
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merge = options.mask && options.readOnly && !skipMasking;
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}
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let payloadLength = dataLength;
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if (dataLength >= 65536) {
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offset += 8;
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payloadLength = 127;
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} else if (dataLength > 125) {
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offset += 2;
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payloadLength = 126;
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}
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const target = Buffer.allocUnsafe(merge ? dataLength + offset : offset);
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target[0] = options.fin ? options.opcode | 0x80 : options.opcode;
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if (options.rsv1) target[0] |= 0x40;
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target[1] = payloadLength;
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if (payloadLength === 126) {
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target.writeUInt16BE(dataLength, 2);
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} else if (payloadLength === 127) {
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target[2] = target[3] = 0;
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target.writeUIntBE(dataLength, 4, 6);
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}
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if (!options.mask) return [target, data];
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target[1] |= 0x80;
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target[offset - 4] = mask[0];
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target[offset - 3] = mask[1];
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target[offset - 2] = mask[2];
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target[offset - 1] = mask[3];
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if (skipMasking) return [target, data];
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if (merge) {
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applyMask(data, mask, target, offset, dataLength);
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return [target];
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}
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applyMask(data, mask, data, 0, dataLength);
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return [target, data];
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}
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/**
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* Sends a close message to the other peer.
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*
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* @param {Number} [code] The status code component of the body
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* @param {(String|Buffer)} [data] The message component of the body
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* @param {Boolean} [mask=false] Specifies whether or not to mask the message
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* @param {Function} [cb] Callback
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* @public
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*/
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close(code, data, mask, cb) {
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let buf;
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if (code === undefined) {
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buf = EMPTY_BUFFER;
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} else if (typeof code !== 'number' || !isValidStatusCode(code)) {
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throw new TypeError('First argument must be a valid error code number');
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} else if (data === undefined || !data.length) {
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buf = Buffer.allocUnsafe(2);
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buf.writeUInt16BE(code, 0);
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} else {
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const length = Buffer.byteLength(data);
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if (length > 123) {
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throw new RangeError('The message must not be greater than 123 bytes');
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}
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buf = Buffer.allocUnsafe(2 + length);
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buf.writeUInt16BE(code, 0);
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if (typeof data === 'string') {
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buf.write(data, 2);
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} else {
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buf.set(data, 2);
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}
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}
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const options = {
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[kByteLength]: buf.length,
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fin: true,
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generateMask: this._generateMask,
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mask,
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maskBuffer: this._maskBuffer,
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opcode: 0x08,
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readOnly: false,
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rsv1: false
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};
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if (this._deflating) {
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this.enqueue([this.dispatch, buf, false, options, cb]);
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} else {
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this.sendFrame(Sender.frame(buf, options), cb);
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}
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}
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/**
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* Sends a ping message to the other peer.
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*
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* @param {*} data The message to send
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* @param {Boolean} [mask=false] Specifies whether or not to mask `data`
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* @param {Function} [cb] Callback
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* @public
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*/
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ping(data, mask, cb) {
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let byteLength;
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let readOnly;
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if (typeof data === 'string') {
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byteLength = Buffer.byteLength(data);
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readOnly = false;
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} else {
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data = toBuffer(data);
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byteLength = data.length;
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readOnly = toBuffer.readOnly;
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}
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if (byteLength > 125) {
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throw new RangeError('The data size must not be greater than 125 bytes');
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}
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const options = {
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[kByteLength]: byteLength,
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fin: true,
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generateMask: this._generateMask,
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mask,
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maskBuffer: this._maskBuffer,
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opcode: 0x09,
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readOnly,
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rsv1: false
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};
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if (this._deflating) {
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this.enqueue([this.dispatch, data, false, options, cb]);
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} else {
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this.sendFrame(Sender.frame(data, options), cb);
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}
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}
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/**
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* Sends a pong message to the other peer.
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*
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* @param {*} data The message to send
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* @param {Boolean} [mask=false] Specifies whether or not to mask `data`
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* @param {Function} [cb] Callback
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* @public
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*/
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pong(data, mask, cb) {
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let byteLength;
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let readOnly;
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if (typeof data === 'string') {
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byteLength = Buffer.byteLength(data);
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readOnly = false;
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} else {
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data = toBuffer(data);
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byteLength = data.length;
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readOnly = toBuffer.readOnly;
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}
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if (byteLength > 125) {
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throw new RangeError('The data size must not be greater than 125 bytes');
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}
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const options = {
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[kByteLength]: byteLength,
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fin: true,
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generateMask: this._generateMask,
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mask,
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maskBuffer: this._maskBuffer,
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opcode: 0x0a,
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readOnly,
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rsv1: false
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};
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if (this._deflating) {
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this.enqueue([this.dispatch, data, false, options, cb]);
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} else {
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this.sendFrame(Sender.frame(data, options), cb);
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}
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}
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/**
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* Sends a data message to the other peer.
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*
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* @param {*} data The message to send
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* @param {Object} options Options object
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* @param {Boolean} [options.binary=false] Specifies whether `data` is binary
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* or text
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* @param {Boolean} [options.compress=false] Specifies whether or not to
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* compress `data`
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* @param {Boolean} [options.fin=false] Specifies whether the fragment is the
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* last one
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* @param {Boolean} [options.mask=false] Specifies whether or not to mask
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* `data`
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* @param {Function} [cb] Callback
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* @public
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*/
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send(data, options, cb) {
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const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
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let opcode = options.binary ? 2 : 1;
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let rsv1 = options.compress;
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let byteLength;
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let readOnly;
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if (typeof data === 'string') {
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byteLength = Buffer.byteLength(data);
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readOnly = false;
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} else {
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data = toBuffer(data);
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byteLength = data.length;
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readOnly = toBuffer.readOnly;
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}
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if (this._firstFragment) {
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this._firstFragment = false;
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if (
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rsv1 &&
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perMessageDeflate &&
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perMessageDeflate.params[
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perMessageDeflate._isServer
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? 'server_no_context_takeover'
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: 'client_no_context_takeover'
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]
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) {
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rsv1 = byteLength >= perMessageDeflate._threshold;
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}
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this._compress = rsv1;
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} else {
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rsv1 = false;
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opcode = 0;
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}
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if (options.fin) this._firstFragment = true;
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if (perMessageDeflate) {
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const opts = {
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[kByteLength]: byteLength,
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fin: options.fin,
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generateMask: this._generateMask,
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mask: options.mask,
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maskBuffer: this._maskBuffer,
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opcode,
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readOnly,
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rsv1
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};
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if (this._deflating) {
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this.enqueue([this.dispatch, data, this._compress, opts, cb]);
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} else {
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this.dispatch(data, this._compress, opts, cb);
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}
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} else {
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this.sendFrame(
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Sender.frame(data, {
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[kByteLength]: byteLength,
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fin: options.fin,
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generateMask: this._generateMask,
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mask: options.mask,
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maskBuffer: this._maskBuffer,
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opcode,
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readOnly,
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rsv1: false
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}),
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cb
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);
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}
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}
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/**
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* Dispatches a message.
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*
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* @param {(Buffer|String)} data The message to send
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* @param {Boolean} [compress=false] Specifies whether or not to compress
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* `data`
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* @param {Object} options Options object
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* @param {Boolean} [options.fin=false] Specifies whether or not to set the
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* FIN bit
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* @param {Function} [options.generateMask] The function used to generate the
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* masking key
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* @param {Boolean} [options.mask=false] Specifies whether or not to mask
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* `data`
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* @param {Buffer} [options.maskBuffer] The buffer used to store the masking
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* key
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* @param {Number} options.opcode The opcode
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* @param {Boolean} [options.readOnly=false] Specifies whether `data` can be
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* modified
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* @param {Boolean} [options.rsv1=false] Specifies whether or not to set the
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* RSV1 bit
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* @param {Function} [cb] Callback
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* @private
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*/
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dispatch(data, compress, options, cb) {
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if (!compress) {
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this.sendFrame(Sender.frame(data, options), cb);
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return;
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}
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const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
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this._bufferedBytes += options[kByteLength];
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this._deflating = true;
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perMessageDeflate.compress(data, options.fin, (_, buf) => {
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if (this._socket.destroyed) {
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const err = new Error(
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'The socket was closed while data was being compressed'
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);
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if (typeof cb === 'function') cb(err);
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for (let i = 0; i < this._queue.length; i++) {
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const params = this._queue[i];
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const callback = params[params.length - 1];
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if (typeof callback === 'function') callback(err);
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}
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return;
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}
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this._bufferedBytes -= options[kByteLength];
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this._deflating = false;
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options.readOnly = false;
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this.sendFrame(Sender.frame(buf, options), cb);
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this.dequeue();
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});
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}
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/**
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* Executes queued send operations.
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*
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* @private
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*/
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dequeue() {
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while (!this._deflating && this._queue.length) {
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const params = this._queue.shift();
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this._bufferedBytes -= params[3][kByteLength];
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Reflect.apply(params[0], this, params.slice(1));
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}
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}
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/**
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* Enqueues a send operation.
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*
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* @param {Array} params Send operation parameters.
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* @private
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*/
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enqueue(params) {
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this._bufferedBytes += params[3][kByteLength];
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this._queue.push(params);
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}
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/**
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* Sends a frame.
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*
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* @param {Buffer[]} list The frame to send
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* @param {Function} [cb] Callback
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* @private
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*/
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sendFrame(list, cb) {
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if (list.length === 2) {
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this._socket.cork();
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this._socket.write(list[0]);
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this._socket.write(list[1], cb);
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this._socket.uncork();
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} else {
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this._socket.write(list[0], cb);
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}
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}
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}
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module.exports = Sender;
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