gnome-shell/js/ui/focusCaretTracker.js
Joaquim Rocha 76c4b0a960 Fix crash when using the magnifier
The first time that the session is started, it can happen that the
AT SPI hasn't been correctly initialized, and this results in a crash
when attempting to register the caret or focus listeners.

In order to avoid this, these changes check the result of initializing
the AT SPI, to allow further attempts when it has failed.

https://bugzilla.gnome.org/show_bug.cgi?id=785047
2017-07-18 09:51:57 +02:00

93 lines
2.9 KiB
JavaScript

/** -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
* Copyright 2012 Inclusive Design Research Centre, OCAD University.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
* Author:
* Joseph Scheuhammer <clown@alum.mit.edu>
* Contributor:
* Magdalen Berns <m.berns@sms.ed.ac.uk>
*/
const Atspi = imports.gi.Atspi;
const Lang = imports.lang;
const Signals = imports.signals;
const CARETMOVED = 'object:text-caret-moved';
const STATECHANGED = 'object:state-changed';
const FocusCaretTracker = new Lang.Class({
Name: 'FocusCaretTracker',
_init: function() {
this._atspiListener = Atspi.EventListener.new(Lang.bind(this, this._onChanged));
this._atspiInited = false;
this._focusListenerRegistered = false;
this._caretListenerRegistered = false;
},
_onChanged: function(event) {
if (event.type.indexOf(STATECHANGED) == 0)
this.emit('focus-changed', event);
else if (event.type == CARETMOVED)
this.emit('caret-moved', event);
},
_initAtspi: function() {
if (!this._atspiInited && Atspi.init() == 0) {
Atspi.set_timeout(250, 250);
this._atspiInited = true;
}
return this._atspiInited;
},
registerFocusListener: function() {
if (!this._initAtspi() || this._focusListenerRegistered)
return;
this._atspiListener.register(STATECHANGED + ':focused');
this._atspiListener.register(STATECHANGED + ':selected');
this._focusListenerRegistered = true;
},
registerCaretListener: function() {
if (!this._initAtspi() || this._caretListenerRegistered)
return;
this._atspiListener.register(CARETMOVED);
this._caretListenerRegistered = true;
},
deregisterFocusListener: function() {
if (!this._focusListenerRegistered)
return;
this._atspiListener.deregister(STATECHANGED + ':focused');
this._atspiListener.deregister(STATECHANGED + ':selected');
this._focusListenerRegistered = false;
},
deregisterCaretListener: function() {
if (!this._caretListenerRegistered)
return;
this._atspiListener.deregister(CARETMOVED);
this._caretListenerRegistered = false;
}
});
Signals.addSignalMethods(FocusCaretTracker.prototype);