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libtdevnc/webclients/novnc/core/input/keyboard.js

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/*
* noVNC: HTML5 VNC client
* Copyright (C) 2012 Joel Martin
* Copyright (C) 2013 Samuel Mannehed for Cendio AB
* 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 function Keyboard(target) {
this._target = target || null;
this._keyDownList = {}; // List of depressed keys
// (even if they are happy)
this._pendingKey = null; // Key waiting for keypress
// keep these here so we can refer to them later
this._eventHandlers = {
'keyup': this._handleKeyUp.bind(this),
'keydown': this._handleKeyDown.bind(this),
'keypress': this._handleKeyPress.bind(this),
'blur': this._allKeysUp.bind(this)
};
};
Keyboard.prototype = {
// ===== EVENT HANDLERS =====
onkeyevent: function () {}, // Handler for key press/release
// ===== PRIVATE METHODS =====
_sendKeyEvent: function (keysym, code, down) {
Log.Debug("onkeyevent " + (down ? "down" : "up") +
", keysym: " + keysym, ", code: " + code);
// Windows sends CtrlLeft+AltRight when you press
// AltGraph, which tends to confuse the hell out of
// remote systems. Fake a release of these keys until
// there is a way to detect AltGraph properly.
var fakeAltGraph = false;
if (down && browser.isWindows()) {
if ((code !== 'ControlLeft') &&
(code !== 'AltRight') &&
('ControlLeft' in this._keyDownList) &&
('AltRight' in this._keyDownList)) {
fakeAltGraph = true;
this.onkeyevent(this._keyDownList['AltRight'],
'AltRight', false);
this.onkeyevent(this._keyDownList['ControlLeft'],
'ControlLeft', false);
}
}
this.onkeyevent(keysym, code, down);
if (fakeAltGraph) {
this.onkeyevent(this._keyDownList['ControlLeft'],
'ControlLeft', true);
this.onkeyevent(this._keyDownList['AltRight'],
'AltRight', true);
}
},
_getKeyCode: function (e) {
var code = KeyboardUtil.getKeycode(e);
if (code !== 'Unidentified') {
return code;
}
// Unstable, but we don't have anything else to go on
// (don't use it for 'keypress' events thought since
// WebKit sets it to the same as charCode)
if (e.keyCode && (e.type !== 'keypress')) {
// 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;
}
var codepoint = parseInt(e.keyIdentifier.substr(2), 16);
var char = String.fromCharCode(codepoint);
// Some implementations fail to uppercase the symbols
char = char.toUpperCase();
return 'Platform' + char.charCodeAt();
}
return 'Unidentified';
},
_handleKeyDown: function (e) {
var code = this._getKeyCode(e);
var keysym = KeyboardUtil.getKeysym(e);
// We cannot handle keys we cannot track, but we also need
// to deal with virtual keyboards which omit key info
// (iOS omits tracking info on keyup events, which forces us to
// special treat that platform here)
if ((code === 'Unidentified') || browser.isIOS()) {
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()) {
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() && (code === 'CapsLock')) {
this._sendKeyEvent(KeyTable.XK_Caps_Lock, 'CapsLock', true);
this._sendKeyEvent(KeyTable.XK_Caps_Lock, 'CapsLock', false);
stopEvent(e);
return;
}
// If this is a legacy browser then we'll need to wait for
// a keypress event as well
// (IE and Edge has a broken KeyboardEvent.key, so we can't
// just check for the presence of that field)
if (!keysym && (!e.key || browser.isIE() || browser.isEdge())) {
this._pendingKey = code;
// However we might not get a keypress event if the key
// is non-printable, which needs some special fallback
// handling
setTimeout(this._handleKeyPressTimeout.bind(this), 10, e);
return;
}
this._pendingKey = null;
stopEvent(e);
this._keyDownList[code] = keysym;
this._sendKeyEvent(keysym, code, true);
},
// Legacy event for browsers without code/key
_handleKeyPress: function (e) {
stopEvent(e);
// Are we expecting a keypress?
if (this._pendingKey === null) {
return;
}
var code = this._getKeyCode(e);
var keysym = KeyboardUtil.getKeysym(e);
// The key we were waiting for?
if ((code !== 'Unidentified') && (code != this._pendingKey)) {
return;
}
code = this._pendingKey;
this._pendingKey = null;
if (!keysym) {
Log.Info('keypress with no keysym:', e);
return;
}
this._keyDownList[code] = keysym;
this._sendKeyEvent(keysym, code, true);
},
_handleKeyPressTimeout: function (e) {
// Did someone manage to sort out the key already?
if (this._pendingKey === null) {
return;
}
var code, keysym;
code = this._pendingKey;
this._pendingKey = null;
// We have no way of knowing the proper keysym with the
// information given, but the following are true for most
// layouts
if ((e.keyCode >= 0x30) && (e.keyCode <= 0x39)) {
// Digit
keysym = e.keyCode;
} else if ((e.keyCode >= 0x41) && (e.keyCode <= 0x5a)) {
// Character (A-Z)
var char = String.fromCharCode(e.keyCode);
// A feeble attempt at the correct case
if (e.shiftKey)
char = char.toUpperCase();
else
char = char.toLowerCase();
keysym = char.charCodeAt();
} else {
// Unknown, give up
keysym = 0;
}
this._keyDownList[code] = keysym;
this._sendKeyEvent(keysym, code, true);
},
_handleKeyUp: function (e) {
stopEvent(e);
var code = this._getKeyCode(e);
// See comment in _handleKeyDown()
if (browser.isMac() && (code === 'CapsLock')) {
this._sendKeyEvent(KeyTable.XK_Caps_Lock, 'CapsLock', true);
this._sendKeyEvent(KeyTable.XK_Caps_Lock, 'CapsLock', false);
return;
}
// Do we really think this key is down?
if (!(code in this._keyDownList)) {
return;
}
this._sendKeyEvent(this._keyDownList[code], code, false);
delete this._keyDownList[code];
},
_allKeysUp: function () {
Log.Debug(">> Keyboard.allKeysUp");
for (var code in this._keyDownList) {
this._sendKeyEvent(this._keyDownList[code], code, false);
};
this._keyDownList = {};
Log.Debug("<< Keyboard.allKeysUp");
},
// ===== PUBLIC METHODS =====
grab: function () {
//Log.Debug(">> Keyboard.grab");
var c = this._target;
c.addEventListener('keydown', this._eventHandlers.keydown);
c.addEventListener('keyup', this._eventHandlers.keyup);
c.addEventListener('keypress', this._eventHandlers.keypress);
// Release (key up) if window loses focus
window.addEventListener('blur', this._eventHandlers.blur);
//Log.Debug("<< Keyboard.grab");
},
ungrab: function () {
//Log.Debug(">> Keyboard.ungrab");
var c = this._target;
c.removeEventListener('keydown', this._eventHandlers.keydown);
c.removeEventListener('keyup', this._eventHandlers.keyup);
c.removeEventListener('keypress', this._eventHandlers.keypress);
window.removeEventListener('blur', this._eventHandlers.blur);
// Release (key up) all keys that are in a down state
this._allKeysUp();
//Log.Debug(">> Keyboard.ungrab");
},
};