mirror of
https://github.com/Ylianst/MeshCentral.git
synced 2024-12-30 09:03:20 -05:00
354 lines
10 KiB
JavaScript
354 lines
10 KiB
JavaScript
/*
|
|
* Websock: high-performance buffering wrapper
|
|
* Copyright (C) 2019 The noVNC Authors
|
|
* Licensed under MPL 2.0 (see LICENSE.txt)
|
|
*
|
|
* Websock is similar to the standard WebSocket / RTCDataChannel object
|
|
* but with extra buffer handling.
|
|
*
|
|
* Websock has built-in receive queue buffering; the message event
|
|
* does not contain actual data but is simply a notification that
|
|
* there is new data available. Several rQ* methods are available to
|
|
* read binary data off of the receive queue.
|
|
*/
|
|
|
|
import * as Log from './util/logging.js';
|
|
|
|
// this has performance issues in some versions Chromium, and
|
|
// doesn't gain a tremendous amount of performance increase in Firefox
|
|
// at the moment. It may be valuable to turn it on in the future.
|
|
const MAX_RQ_GROW_SIZE = 40 * 1024 * 1024; // 40 MiB
|
|
|
|
// Constants pulled from RTCDataChannelState enum
|
|
// https://developer.mozilla.org/en-US/docs/Web/API/RTCDataChannel/readyState#RTCDataChannelState_enum
|
|
const DataChannel = {
|
|
CONNECTING: "connecting",
|
|
OPEN: "open",
|
|
CLOSING: "closing",
|
|
CLOSED: "closed"
|
|
};
|
|
|
|
const ReadyStates = {
|
|
CONNECTING: [WebSocket.CONNECTING, DataChannel.CONNECTING],
|
|
OPEN: [WebSocket.OPEN, DataChannel.OPEN],
|
|
CLOSING: [WebSocket.CLOSING, DataChannel.CLOSING],
|
|
CLOSED: [WebSocket.CLOSED, DataChannel.CLOSED],
|
|
};
|
|
|
|
// Properties a raw channel must have, WebSocket and RTCDataChannel are two examples
|
|
const rawChannelProps = [
|
|
"send",
|
|
"close",
|
|
"binaryType",
|
|
"onerror",
|
|
"onmessage",
|
|
"onopen",
|
|
"protocol",
|
|
"readyState",
|
|
];
|
|
|
|
export default class Websock {
|
|
constructor() {
|
|
this._websocket = null; // WebSocket or RTCDataChannel object
|
|
|
|
this._rQi = 0; // Receive queue index
|
|
this._rQlen = 0; // Next write position in the receive queue
|
|
this._rQbufferSize = 1024 * 1024 * 4; // Receive queue buffer size (4 MiB)
|
|
// called in init: this._rQ = new Uint8Array(this._rQbufferSize);
|
|
this._rQ = null; // Receive queue
|
|
|
|
this._sQbufferSize = 1024 * 10; // 10 KiB
|
|
// called in init: this._sQ = new Uint8Array(this._sQbufferSize);
|
|
this._sQlen = 0;
|
|
this._sQ = null; // Send queue
|
|
|
|
this._eventHandlers = {
|
|
message: () => {},
|
|
open: () => {},
|
|
close: () => {},
|
|
error: () => {}
|
|
};
|
|
}
|
|
|
|
// Getters and Setters
|
|
|
|
get readyState() {
|
|
let subState;
|
|
|
|
if (this._websocket === null) {
|
|
return "unused";
|
|
}
|
|
|
|
subState = this._websocket.readyState;
|
|
|
|
if (ReadyStates.CONNECTING.includes(subState)) {
|
|
return "connecting";
|
|
} else if (ReadyStates.OPEN.includes(subState)) {
|
|
return "open";
|
|
} else if (ReadyStates.CLOSING.includes(subState)) {
|
|
return "closing";
|
|
} else if (ReadyStates.CLOSED.includes(subState)) {
|
|
return "closed";
|
|
}
|
|
|
|
return "unknown";
|
|
}
|
|
|
|
get sQ() {
|
|
return this._sQ;
|
|
}
|
|
|
|
get rQ() {
|
|
return this._rQ;
|
|
}
|
|
|
|
get rQi() {
|
|
return this._rQi;
|
|
}
|
|
|
|
set rQi(val) {
|
|
this._rQi = val;
|
|
}
|
|
|
|
// Receive Queue
|
|
get rQlen() {
|
|
return this._rQlen - this._rQi;
|
|
}
|
|
|
|
rQpeek8() {
|
|
return this._rQ[this._rQi];
|
|
}
|
|
|
|
rQskipBytes(bytes) {
|
|
this._rQi += bytes;
|
|
}
|
|
|
|
rQshift8() {
|
|
return this._rQshift(1);
|
|
}
|
|
|
|
rQshift16() {
|
|
return this._rQshift(2);
|
|
}
|
|
|
|
rQshift32() {
|
|
return this._rQshift(4);
|
|
}
|
|
|
|
// TODO(directxman12): test performance with these vs a DataView
|
|
_rQshift(bytes) {
|
|
let res = 0;
|
|
for (let byte = bytes - 1; byte >= 0; byte--) {
|
|
res += this._rQ[this._rQi++] << (byte * 8);
|
|
}
|
|
return res;
|
|
}
|
|
|
|
rQshiftStr(len) {
|
|
if (typeof(len) === 'undefined') { len = this.rQlen; }
|
|
let str = "";
|
|
// Handle large arrays in steps to avoid long strings on the stack
|
|
for (let i = 0; i < len; i += 4096) {
|
|
let part = this.rQshiftBytes(Math.min(4096, len - i));
|
|
str += String.fromCharCode.apply(null, part);
|
|
}
|
|
return str;
|
|
}
|
|
|
|
rQshiftBytes(len) {
|
|
if (typeof(len) === 'undefined') { len = this.rQlen; }
|
|
this._rQi += len;
|
|
return new Uint8Array(this._rQ.buffer, this._rQi - len, len);
|
|
}
|
|
|
|
rQshiftTo(target, len) {
|
|
if (len === undefined) { len = this.rQlen; }
|
|
// TODO: make this just use set with views when using a ArrayBuffer to store the rQ
|
|
target.set(new Uint8Array(this._rQ.buffer, this._rQi, len));
|
|
this._rQi += len;
|
|
}
|
|
|
|
rQslice(start, end = this.rQlen) {
|
|
return new Uint8Array(this._rQ.buffer, this._rQi + start, end - start);
|
|
}
|
|
|
|
// Check to see if we must wait for 'num' bytes (default to FBU.bytes)
|
|
// to be available in the receive queue. Return true if we need to
|
|
// wait (and possibly print a debug message), otherwise false.
|
|
rQwait(msg, num, goback) {
|
|
if (this.rQlen < num) {
|
|
if (goback) {
|
|
if (this._rQi < goback) {
|
|
throw new Error("rQwait cannot backup " + goback + " bytes");
|
|
}
|
|
this._rQi -= goback;
|
|
}
|
|
return true; // true means need more data
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Send Queue
|
|
|
|
flush() {
|
|
if (this._sQlen > 0 && this.readyState === 'open') {
|
|
this._websocket.send(this._encodeMessage());
|
|
this._sQlen = 0;
|
|
}
|
|
}
|
|
|
|
send(arr) {
|
|
this._sQ.set(arr, this._sQlen);
|
|
this._sQlen += arr.length;
|
|
this.flush();
|
|
}
|
|
|
|
sendString(str) {
|
|
this.send(str.split('').map(chr => chr.charCodeAt(0)));
|
|
}
|
|
|
|
// Event Handlers
|
|
off(evt) {
|
|
this._eventHandlers[evt] = () => {};
|
|
}
|
|
|
|
on(evt, handler) {
|
|
this._eventHandlers[evt] = handler;
|
|
}
|
|
|
|
_allocateBuffers() {
|
|
this._rQ = new Uint8Array(this._rQbufferSize);
|
|
this._sQ = new Uint8Array(this._sQbufferSize);
|
|
}
|
|
|
|
init() {
|
|
this._allocateBuffers();
|
|
this._rQi = 0;
|
|
this._websocket = null;
|
|
}
|
|
|
|
open(uri, protocols) {
|
|
this.attach(new WebSocket(uri, protocols));
|
|
}
|
|
|
|
attach(rawChannel) {
|
|
this.init();
|
|
|
|
// Must get object and class methods to be compatible with the tests.
|
|
const channelProps = [...Object.keys(rawChannel), ...Object.getOwnPropertyNames(Object.getPrototypeOf(rawChannel))];
|
|
for (let i = 0; i < rawChannelProps.length; i++) {
|
|
const prop = rawChannelProps[i];
|
|
if (channelProps.indexOf(prop) < 0) {
|
|
throw new Error('Raw channel missing property: ' + prop);
|
|
}
|
|
}
|
|
|
|
this._websocket = rawChannel;
|
|
this._websocket.binaryType = "arraybuffer";
|
|
this._websocket.onmessage = this._recvMessage.bind(this);
|
|
|
|
this._websocket.onopen = () => {
|
|
Log.Debug('>> WebSock.onopen');
|
|
if (this._websocket.protocol) {
|
|
Log.Info("Server choose sub-protocol: " + this._websocket.protocol);
|
|
}
|
|
|
|
this._eventHandlers.open();
|
|
Log.Debug("<< WebSock.onopen");
|
|
};
|
|
|
|
this._websocket.onclose = (e) => {
|
|
Log.Debug(">> WebSock.onclose");
|
|
this._eventHandlers.close(e);
|
|
Log.Debug("<< WebSock.onclose");
|
|
};
|
|
|
|
this._websocket.onerror = (e) => {
|
|
Log.Debug(">> WebSock.onerror: " + e);
|
|
this._eventHandlers.error(e);
|
|
Log.Debug("<< WebSock.onerror: " + e);
|
|
};
|
|
}
|
|
|
|
close() {
|
|
if (this._websocket) {
|
|
if (this.readyState === 'connecting' ||
|
|
this.readyState === 'open') {
|
|
Log.Info("Closing WebSocket connection");
|
|
this._websocket.close();
|
|
}
|
|
|
|
this._websocket.onmessage = () => {};
|
|
}
|
|
}
|
|
|
|
// private methods
|
|
_encodeMessage() {
|
|
// Put in a binary arraybuffer
|
|
// according to the spec, you can send ArrayBufferViews with the send method
|
|
return new Uint8Array(this._sQ.buffer, 0, this._sQlen);
|
|
}
|
|
|
|
// We want to move all the unread data to the start of the queue,
|
|
// e.g. compacting.
|
|
// The function also expands the receive que if needed, and for
|
|
// performance reasons we combine these two actions to avoid
|
|
// unneccessary copying.
|
|
_expandCompactRQ(minFit) {
|
|
// if we're using less than 1/8th of the buffer even with the incoming bytes, compact in place
|
|
// instead of resizing
|
|
const requiredBufferSize = (this._rQlen - this._rQi + minFit) * 8;
|
|
const resizeNeeded = this._rQbufferSize < requiredBufferSize;
|
|
|
|
if (resizeNeeded) {
|
|
// Make sure we always *at least* double the buffer size, and have at least space for 8x
|
|
// the current amount of data
|
|
this._rQbufferSize = Math.max(this._rQbufferSize * 2, requiredBufferSize);
|
|
}
|
|
|
|
// we don't want to grow unboundedly
|
|
if (this._rQbufferSize > MAX_RQ_GROW_SIZE) {
|
|
this._rQbufferSize = MAX_RQ_GROW_SIZE;
|
|
if (this._rQbufferSize - this.rQlen < minFit) {
|
|
throw new Error("Receive Queue buffer exceeded " + MAX_RQ_GROW_SIZE + " bytes, and the new message could not fit");
|
|
}
|
|
}
|
|
|
|
if (resizeNeeded) {
|
|
const oldRQbuffer = this._rQ.buffer;
|
|
this._rQ = new Uint8Array(this._rQbufferSize);
|
|
this._rQ.set(new Uint8Array(oldRQbuffer, this._rQi, this._rQlen - this._rQi));
|
|
} else {
|
|
this._rQ.copyWithin(0, this._rQi, this._rQlen);
|
|
}
|
|
|
|
this._rQlen = this._rQlen - this._rQi;
|
|
this._rQi = 0;
|
|
}
|
|
|
|
// push arraybuffer values onto the end of the receive que
|
|
_DecodeMessage(data) {
|
|
const u8 = new Uint8Array(data);
|
|
if (u8.length > this._rQbufferSize - this._rQlen) {
|
|
this._expandCompactRQ(u8.length);
|
|
}
|
|
this._rQ.set(u8, this._rQlen);
|
|
this._rQlen += u8.length;
|
|
}
|
|
|
|
_recvMessage(e) {
|
|
this._DecodeMessage(e.data);
|
|
if (this.rQlen > 0) {
|
|
this._eventHandlers.message();
|
|
if (this._rQlen == this._rQi) {
|
|
// All data has now been processed, this means we
|
|
// can reset the receive queue.
|
|
this._rQlen = 0;
|
|
this._rQi = 0;
|
|
}
|
|
} else {
|
|
Log.Debug("Ignoring empty message");
|
|
}
|
|
}
|
|
}
|