MeshCentral/public/novnc/core/input/keyboard.js
2021-11-29 12:08:15 -08:00

274 lines
9.5 KiB
JavaScript

/*
* noVNC: HTML5 VNC client
* Copyright (C) 2019 The noVNC Authors
* Licensed under MPL 2.0 or any later version (see LICENSE.txt)
*/
import * as Log from '../util/logging.js';
import { stopEvent } from '../util/events.js';
import * as KeyboardUtil from "./util.js";
import KeyTable from "./keysym.js";
import * as browser from "../util/browser.js";
//
// Keyboard event handler
//
export default class Keyboard {
constructor(target) {
this._target = target || null;
this._keyDownList = {}; // List of depressed keys
// (even if they are happy)
this._altGrArmed = false; // Windows AltGr detection
// keep these here so we can refer to them later
this._eventHandlers = {
'keyup': this._handleKeyUp.bind(this),
'keydown': this._handleKeyDown.bind(this),
'blur': this._allKeysUp.bind(this),
};
// ===== EVENT HANDLERS =====
this.onkeyevent = () => {}; // Handler for key press/release
}
// ===== PRIVATE METHODS =====
_sendKeyEvent(keysym, code, down) {
if (down) {
this._keyDownList[code] = keysym;
} else {
// Do we really think this key is down?
if (!(code in this._keyDownList)) {
return;
}
delete this._keyDownList[code];
}
Log.Debug("onkeyevent " + (down ? "down" : "up") +
", keysym: " + keysym, ", code: " + code);
this.onkeyevent(keysym, code, down);
}
_getKeyCode(e) {
const code = KeyboardUtil.getKeycode(e);
if (code !== 'Unidentified') {
return code;
}
// Unstable, but we don't have anything else to go on
if (e.keyCode) {
// 229 is used for composition events
if (e.keyCode !== 229) {
return 'Platform' + e.keyCode;
}
}
// A precursor to the final DOM3 standard. Unfortunately it
// is not layout independent, so it is as bad as using keyCode
if (e.keyIdentifier) {
// Non-character key?
if (e.keyIdentifier.substr(0, 2) !== 'U+') {
return e.keyIdentifier;
}
const codepoint = parseInt(e.keyIdentifier.substr(2), 16);
const char = String.fromCharCode(codepoint).toUpperCase();
return 'Platform' + char.charCodeAt();
}
return 'Unidentified';
}
_handleKeyDown(e) {
const code = this._getKeyCode(e);
let keysym = KeyboardUtil.getKeysym(e);
// Windows doesn't have a proper AltGr, but handles it using
// fake Ctrl+Alt. However the remote end might not be Windows,
// so we need to merge those in to a single AltGr event. We
// detect this case by seeing the two key events directly after
// each other with a very short time between them (<50ms).
if (this._altGrArmed) {
this._altGrArmed = false;
clearTimeout(this._altGrTimeout);
if ((code === "AltRight") &&
((e.timeStamp - this._altGrCtrlTime) < 50)) {
// FIXME: We fail to detect this if either Ctrl key is
// first manually pressed as Windows then no
// longer sends the fake Ctrl down event. It
// does however happily send real Ctrl events
// even when AltGr is already down. Some
// browsers detect this for us though and set the
// key to "AltGraph".
keysym = KeyTable.XK_ISO_Level3_Shift;
} else {
this._sendKeyEvent(KeyTable.XK_Control_L, "ControlLeft", true);
}
}
// We cannot handle keys we cannot track, but we also need
// to deal with virtual keyboards which omit key info
if (code === 'Unidentified') {
if (keysym) {
// If it's a virtual keyboard then it should be
// sufficient to just send press and release right
// after each other
this._sendKeyEvent(keysym, code, true);
this._sendKeyEvent(keysym, code, false);
}
stopEvent(e);
return;
}
// Alt behaves more like AltGraph on macOS, so shuffle the
// keys around a bit to make things more sane for the remote
// server. This method is used by RealVNC and TigerVNC (and
// possibly others).
if (browser.isMac() || browser.isIOS()) {
switch (keysym) {
case KeyTable.XK_Super_L:
keysym = KeyTable.XK_Alt_L;
break;
case KeyTable.XK_Super_R:
keysym = KeyTable.XK_Super_L;
break;
case KeyTable.XK_Alt_L:
keysym = KeyTable.XK_Mode_switch;
break;
case KeyTable.XK_Alt_R:
keysym = KeyTable.XK_ISO_Level3_Shift;
break;
}
}
// Is this key already pressed? If so, then we must use the
// same keysym or we'll confuse the server
if (code in this._keyDownList) {
keysym = this._keyDownList[code];
}
// macOS doesn't send proper key events for modifiers, only
// state change events. That gets extra confusing for CapsLock
// which toggles on each press, but not on release. So pretend
// it was a quick press and release of the button.
if ((browser.isMac() || browser.isIOS()) && (code === 'CapsLock')) {
this._sendKeyEvent(KeyTable.XK_Caps_Lock, 'CapsLock', true);
this._sendKeyEvent(KeyTable.XK_Caps_Lock, 'CapsLock', false);
stopEvent(e);
return;
}
// Windows doesn't send proper key releases for a bunch of
// Japanese IM keys so we have to fake the release right away
const jpBadKeys = [ KeyTable.XK_Zenkaku_Hankaku,
KeyTable.XK_Eisu_toggle,
KeyTable.XK_Katakana,
KeyTable.XK_Hiragana,
KeyTable.XK_Romaji ];
if (browser.isWindows() && jpBadKeys.includes(keysym)) {
this._sendKeyEvent(keysym, code, true);
this._sendKeyEvent(keysym, code, false);
stopEvent(e);
return;
}
stopEvent(e);
// Possible start of AltGr sequence? (see above)
if ((code === "ControlLeft") && browser.isWindows() &&
!("ControlLeft" in this._keyDownList)) {
this._altGrArmed = true;
this._altGrTimeout = setTimeout(this._handleAltGrTimeout.bind(this), 100);
this._altGrCtrlTime = e.timeStamp;
return;
}
this._sendKeyEvent(keysym, code, true);
}
_handleKeyUp(e) {
stopEvent(e);
const code = this._getKeyCode(e);
// We can't get a release in the middle of an AltGr sequence, so
// abort that detection
if (this._altGrArmed) {
this._altGrArmed = false;
clearTimeout(this._altGrTimeout);
this._sendKeyEvent(KeyTable.XK_Control_L, "ControlLeft", true);
}
// See comment in _handleKeyDown()
if ((browser.isMac() || browser.isIOS()) && (code === 'CapsLock')) {
this._sendKeyEvent(KeyTable.XK_Caps_Lock, 'CapsLock', true);
this._sendKeyEvent(KeyTable.XK_Caps_Lock, 'CapsLock', false);
return;
}
this._sendKeyEvent(this._keyDownList[code], code, false);
// Windows has a rather nasty bug where it won't send key
// release events for a Shift button if the other Shift is still
// pressed
if (browser.isWindows() && ((code === 'ShiftLeft') ||
(code === 'ShiftRight'))) {
if ('ShiftRight' in this._keyDownList) {
this._sendKeyEvent(this._keyDownList['ShiftRight'],
'ShiftRight', false);
}
if ('ShiftLeft' in this._keyDownList) {
this._sendKeyEvent(this._keyDownList['ShiftLeft'],
'ShiftLeft', false);
}
}
}
_handleAltGrTimeout() {
this._altGrArmed = false;
clearTimeout(this._altGrTimeout);
this._sendKeyEvent(KeyTable.XK_Control_L, "ControlLeft", true);
}
_allKeysUp() {
Log.Debug(">> Keyboard.allKeysUp");
for (let code in this._keyDownList) {
this._sendKeyEvent(this._keyDownList[code], code, false);
}
Log.Debug("<< Keyboard.allKeysUp");
}
// ===== PUBLIC METHODS =====
grab() {
//Log.Debug(">> Keyboard.grab");
this._target.addEventListener('keydown', this._eventHandlers.keydown);
this._target.addEventListener('keyup', this._eventHandlers.keyup);
// Release (key up) if window loses focus
window.addEventListener('blur', this._eventHandlers.blur);
//Log.Debug("<< Keyboard.grab");
}
ungrab() {
//Log.Debug(">> Keyboard.ungrab");
this._target.removeEventListener('keydown', this._eventHandlers.keydown);
this._target.removeEventListener('keyup', this._eventHandlers.keyup);
window.removeEventListener('blur', this._eventHandlers.blur);
// Release (key up) all keys that are in a down state
this._allKeysUp();
//Log.Debug(">> Keyboard.ungrab");
}
}