317 lines
9.7 KiB
JavaScript
317 lines
9.7 KiB
JavaScript
/*
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* Websock: high-performance binary WebSockets
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* Copyright (C) 2012 Joel Martin
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* Licensed under MPL 2.0 (see LICENSE.txt)
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*
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* Websock is similar to the standard WebSocket object but with extra
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* buffer handling.
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*
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* Websock has built-in receive queue buffering; the message event
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* does not contain actual data but is simply a notification that
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* there is new data available. Several rQ* methods are available to
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* read binary data off of the receive queue.
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*/
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import * as Log from './util/logging.js';
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export default function Websock() {
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"use strict";
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this._websocket = null; // WebSocket object
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this._rQi = 0; // Receive queue index
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this._rQlen = 0; // Next write position in the receive queue
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this._rQbufferSize = 1024 * 1024 * 4; // Receive queue buffer size (4 MiB)
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this._rQmax = this._rQbufferSize / 8;
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// called in init: this._rQ = new Uint8Array(this._rQbufferSize);
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this._rQ = null; // Receive queue
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this._sQbufferSize = 1024 * 10; // 10 KiB
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// called in init: this._sQ = new Uint8Array(this._sQbufferSize);
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this._sQlen = 0;
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this._sQ = null; // Send queue
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this._eventHandlers = {
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'message': function () {},
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'open': function () {},
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'close': function () {},
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'error': function () {}
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};
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};
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// this has performance issues in some versions Chromium, and
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// doesn't gain a tremendous amount of performance increase in Firefox
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// at the moment. It may be valuable to turn it on in the future.
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var ENABLE_COPYWITHIN = false;
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var MAX_RQ_GROW_SIZE = 40 * 1024 * 1024; // 40 MiB
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var typedArrayToString = (function () {
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// This is only for PhantomJS, which doesn't like apply-ing
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// with Typed Arrays
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try {
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var arr = new Uint8Array([1, 2, 3]);
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String.fromCharCode.apply(null, arr);
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return function (a) { return String.fromCharCode.apply(null, a); };
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} catch (ex) {
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return function (a) {
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return String.fromCharCode.apply(
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null, Array.prototype.slice.call(a));
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};
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}
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})();
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Websock.prototype = {
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// Getters and Setters
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get_sQ: function () {
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return this._sQ;
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},
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get_rQ: function () {
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return this._rQ;
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},
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get_rQi: function () {
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return this._rQi;
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},
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set_rQi: function (val) {
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this._rQi = val;
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},
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// Receive Queue
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rQlen: function () {
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return this._rQlen - this._rQi;
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},
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rQpeek8: function () {
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return this._rQ[this._rQi];
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},
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rQshift8: function () {
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return this._rQ[this._rQi++];
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},
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rQskip8: function () {
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this._rQi++;
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},
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rQskipBytes: function (num) {
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this._rQi += num;
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},
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// TODO(directxman12): test performance with these vs a DataView
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rQshift16: function () {
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return (this._rQ[this._rQi++] << 8) +
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this._rQ[this._rQi++];
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},
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rQshift32: function () {
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return (this._rQ[this._rQi++] << 24) +
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(this._rQ[this._rQi++] << 16) +
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(this._rQ[this._rQi++] << 8) +
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this._rQ[this._rQi++];
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},
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rQshiftStr: function (len) {
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if (typeof(len) === 'undefined') { len = this.rQlen(); }
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var arr = new Uint8Array(this._rQ.buffer, this._rQi, len);
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this._rQi += len;
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return typedArrayToString(arr);
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},
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rQshiftBytes: function (len) {
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if (typeof(len) === 'undefined') { len = this.rQlen(); }
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this._rQi += len;
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return new Uint8Array(this._rQ.buffer, this._rQi - len, len);
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},
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rQshiftTo: function (target, len) {
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if (len === undefined) { len = this.rQlen(); }
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// TODO: make this just use set with views when using a ArrayBuffer to store the rQ
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target.set(new Uint8Array(this._rQ.buffer, this._rQi, len));
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this._rQi += len;
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},
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rQwhole: function () {
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return new Uint8Array(this._rQ.buffer, 0, this._rQlen);
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},
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rQslice: function (start, end) {
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if (end) {
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return new Uint8Array(this._rQ.buffer, this._rQi + start, end - start);
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} else {
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return new Uint8Array(this._rQ.buffer, this._rQi + start, this._rQlen - this._rQi - start);
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}
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},
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// Check to see if we must wait for 'num' bytes (default to FBU.bytes)
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// to be available in the receive queue. Return true if we need to
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// wait (and possibly print a debug message), otherwise false.
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rQwait: function (msg, num, goback) {
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var rQlen = this._rQlen - this._rQi; // Skip rQlen() function call
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if (rQlen < num) {
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if (goback) {
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if (this._rQi < goback) {
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throw new Error("rQwait cannot backup " + goback + " bytes");
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}
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this._rQi -= goback;
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}
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return true; // true means need more data
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}
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return false;
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},
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// Send Queue
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flush: function () {
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if (this._sQlen > 0 && this._websocket.readyState === WebSocket.OPEN) {
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this._websocket.send(this._encode_message());
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this._sQlen = 0;
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}
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},
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send: function (arr) {
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this._sQ.set(arr, this._sQlen);
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this._sQlen += arr.length;
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this.flush();
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},
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send_string: function (str) {
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this.send(str.split('').map(function (chr) {
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return chr.charCodeAt(0);
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}));
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},
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// Event Handlers
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off: function (evt) {
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this._eventHandlers[evt] = function () {};
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},
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on: function (evt, handler) {
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this._eventHandlers[evt] = handler;
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},
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_allocate_buffers: function () {
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this._rQ = new Uint8Array(this._rQbufferSize);
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this._sQ = new Uint8Array(this._sQbufferSize);
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},
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init: function () {
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this._allocate_buffers();
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this._rQi = 0;
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this._websocket = null;
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},
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open: function (uri, protocols) {
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var ws_schema = uri.match(/^([a-z]+):\/\//)[1];
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this.init();
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this._websocket = new WebSocket(uri, protocols);
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this._websocket.binaryType = 'arraybuffer';
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this._websocket.onmessage = this._recv_message.bind(this);
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this._websocket.onopen = (function () {
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Log.Debug('>> WebSock.onopen');
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if (this._websocket.protocol) {
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Log.Info("Server choose sub-protocol: " + this._websocket.protocol);
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}
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this._eventHandlers.open();
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Log.Debug("<< WebSock.onopen");
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}).bind(this);
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this._websocket.onclose = (function (e) {
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Log.Debug(">> WebSock.onclose");
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this._eventHandlers.close(e);
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Log.Debug("<< WebSock.onclose");
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}).bind(this);
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this._websocket.onerror = (function (e) {
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Log.Debug(">> WebSock.onerror: " + e);
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this._eventHandlers.error(e);
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Log.Debug("<< WebSock.onerror: " + e);
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}).bind(this);
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},
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close: function () {
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if (this._websocket) {
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if ((this._websocket.readyState === WebSocket.OPEN) ||
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(this._websocket.readyState === WebSocket.CONNECTING)) {
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Log.Info("Closing WebSocket connection");
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this._websocket.close();
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}
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this._websocket.onmessage = function (e) { return; };
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}
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},
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// private methods
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_encode_message: function () {
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// Put in a binary arraybuffer
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// according to the spec, you can send ArrayBufferViews with the send method
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return new Uint8Array(this._sQ.buffer, 0, this._sQlen);
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},
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_expand_compact_rQ: function (min_fit) {
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var resizeNeeded = min_fit || this._rQlen - this._rQi > this._rQbufferSize / 2;
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if (resizeNeeded) {
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if (!min_fit) {
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// just double the size if we need to do compaction
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this._rQbufferSize *= 2;
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} else {
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// otherwise, make sure we satisy rQlen - rQi + min_fit < rQbufferSize / 8
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this._rQbufferSize = (this._rQlen - this._rQi + min_fit) * 8;
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}
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}
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// we don't want to grow unboundedly
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if (this._rQbufferSize > MAX_RQ_GROW_SIZE) {
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this._rQbufferSize = MAX_RQ_GROW_SIZE;
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if (this._rQbufferSize - this._rQlen - this._rQi < min_fit) {
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throw new Exception("Receive Queue buffer exceeded " + MAX_RQ_GROW_SIZE + " bytes, and the new message could not fit");
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}
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}
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if (resizeNeeded) {
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var old_rQbuffer = this._rQ.buffer;
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this._rQmax = this._rQbufferSize / 8;
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this._rQ = new Uint8Array(this._rQbufferSize);
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this._rQ.set(new Uint8Array(old_rQbuffer, this._rQi));
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} else {
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if (ENABLE_COPYWITHIN) {
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this._rQ.copyWithin(0, this._rQi);
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} else {
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this._rQ.set(new Uint8Array(this._rQ.buffer, this._rQi));
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}
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}
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this._rQlen = this._rQlen - this._rQi;
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this._rQi = 0;
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},
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_decode_message: function (data) {
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// push arraybuffer values onto the end
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var u8 = new Uint8Array(data);
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if (u8.length > this._rQbufferSize - this._rQlen) {
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this._expand_compact_rQ(u8.length);
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}
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this._rQ.set(u8, this._rQlen);
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this._rQlen += u8.length;
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},
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_recv_message: function (e) {
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this._decode_message(e.data);
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if (this.rQlen() > 0) {
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this._eventHandlers.message();
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// Compact the receive queue
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if (this._rQlen == this._rQi) {
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this._rQlen = 0;
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this._rQi = 0;
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} else if (this._rQlen > this._rQmax) {
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this._expand_compact_rQ();
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}
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} else {
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Log.Debug("Ignoring empty message");
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}
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}
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};
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