From 24a04f3b71f18e37b655a5e717540a3dc3bef598 Mon Sep 17 00:00:00 2001 From: Colomban Wendling Date: Wed, 10 Jun 2020 18:54:37 +0200 Subject: a11y-keyboard: Add support for ringing the bell when CapsLock is active --- plugins/a11y-keyboard/msd-a11y-keyboard-atspi.c | 208 ++++++++++++++++++++++++ 1 file changed, 208 insertions(+) create mode 100644 plugins/a11y-keyboard/msd-a11y-keyboard-atspi.c (limited to 'plugins/a11y-keyboard/msd-a11y-keyboard-atspi.c') diff --git a/plugins/a11y-keyboard/msd-a11y-keyboard-atspi.c b/plugins/a11y-keyboard/msd-a11y-keyboard-atspi.c new file mode 100644 index 0000000..c6cafed --- /dev/null +++ b/plugins/a11y-keyboard/msd-a11y-keyboard-atspi.c @@ -0,0 +1,208 @@ +/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*- + * + * Copyright (C) 2020 Colomban Wendling + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +#include "config.h" + +#include "msd-a11y-keyboard-atspi.h" + +#include + +#ifdef HAVE_LIBATSPI +#include +#include + + +/* ugly workaround https://gitlab.gnome.org/GNOME/at-spi2-core/-/issues/22 */ +static AtspiDeviceListener * +WORKAROUND_atspi_device_listener_new (AtspiDeviceListenerCB callback, + void *user_data, + GDestroyNotify callback_destroyed) +{ + AtspiDeviceListener *listener; + + listener = atspi_device_listener_new (callback, user_data, + callback_destroyed); + + /* Yes, we do leak a reference. But we have to, because there's a + * nasty bug in libatspi [1] where if a listener is destroyed it leads + * to invalid memory access and potentially a crash. + * [1] https://gitlab.gnome.org/GNOME/at-spi2-core/-/issues/22 */ + return g_object_ref (listener); +} +#define atspi_device_listener_new WORKAROUND_atspi_device_listener_new + + +struct MsdA11yKeyboardAtspiPrivate +{ + AtspiDeviceListener *listener; + gboolean listening; +}; + +G_DEFINE_TYPE_WITH_PRIVATE (MsdA11yKeyboardAtspi, msd_a11y_keyboard_atspi, G_TYPE_OBJECT) + +static void +msd_a11y_keyboard_atspi_finalize (GObject *obj) +{ + MsdA11yKeyboardAtspi *self = MSD_A11Y_KEYBOARD_ATSPI (obj); + + g_clear_object (&self->priv->listener); + self->priv->listening = FALSE; + + G_OBJECT_CLASS (msd_a11y_keyboard_atspi_parent_class)->finalize (obj); +} + +static void +msd_a11y_keyboard_atspi_class_init (MsdA11yKeyboardAtspiClass *klass) +{ + GObjectClass *object_class = G_OBJECT_CLASS (klass); + + object_class->finalize = msd_a11y_keyboard_atspi_finalize; +} + +static gboolean +on_key_press_event (const AtspiDeviceEvent *event, + void *user_data G_GNUC_UNUSED) +{ + /* don't ring when disabling capslock */ + if (event->id == GDK_KEY_Caps_Lock && + event->modifiers & (1 << ATSPI_MODIFIER_SHIFTLOCK)) + return FALSE; + + gdk_display_beep (gdk_display_get_default ()); + + return FALSE; +} + +static void +msd_a11y_keyboard_atspi_init (MsdA11yKeyboardAtspi *self) +{ + self->priv = msd_a11y_keyboard_atspi_get_instance_private (self); + + /* init AT-SPI if needed */ + atspi_init (); + + /* Ideally we'd create the listener in start() only -- we don't need + * it otherwise. But there's a bug [1] in libatspi where destroying a + * listener leads to a crash, so we have a workaround keeping the + * listener alive, and thus try and avoid creating (and not destroying) + * listener more often than absolutely necessary. + * [1] https://gitlab.gnome.org/GNOME/at-spi2-core/-/issues/22 */ + self->priv->listener = atspi_device_listener_new (on_key_press_event, + self, NULL); + self->priv->listening = FALSE; +} + +static void +register_deregister_events (MsdA11yKeyboardAtspi *self, + gboolean do_register) +{ + AtspiKeyDefinition shiftlock_key; + GArray *shiftlock_key_set; + + g_return_if_fail (MSD_IS_A11Y_KEYBOARD_ATSPI (self)); + g_return_if_fail (ATSPI_IS_DEVICE_LISTENER (self->priv->listener)); + + /* register listeners for CAPS_LOCK with any modifier but CAPS_LOCK, + * and all keys with CAPS_LOCK modifier, so we grab when CAPS_LOCK is + * active or gets activated */ + shiftlock_key.keycode = 0; + shiftlock_key.keysym = GDK_KEY_Caps_Lock; + shiftlock_key.keystring = NULL; + + shiftlock_key_set = g_array_new (FALSE, FALSE, sizeof shiftlock_key); + g_array_append_val (shiftlock_key_set, shiftlock_key); + + for (AtspiKeyMaskType mod_mask = 0; mod_mask < 256; mod_mask++) + { + GArray *key_set; + + if (mod_mask & (1 << ATSPI_MODIFIER_SHIFTLOCK)) + key_set = NULL; + else + key_set = shiftlock_key_set; + + if (do_register) + atspi_register_keystroke_listener (self->priv->listener, + key_set, + mod_mask, + 1 << ATSPI_KEY_PRESSED_EVENT, + ATSPI_KEYLISTENER_NOSYNC, + NULL); + else + atspi_deregister_keystroke_listener (self->priv->listener, + key_set, + mod_mask, + 1 << ATSPI_KEY_PRESSED_EVENT, + NULL); + } + + g_array_unref (shiftlock_key_set); + + self->priv->listening = do_register; +} + +void +msd_a11y_keyboard_atspi_start (MsdA11yKeyboardAtspi *self) +{ + g_return_if_fail (MSD_IS_A11Y_KEYBOARD_ATSPI (self)); + + if (! self->priv->listening) + register_deregister_events (self, TRUE); +} + +void +msd_a11y_keyboard_atspi_stop (MsdA11yKeyboardAtspi *self) +{ + g_return_if_fail (MSD_IS_A11Y_KEYBOARD_ATSPI (self)); + + if (self->priv->listening) + register_deregister_events (self, FALSE); +} + +#else /* ! defined(HAVE_LIBATSPI): AT-SPI is not available, provide stubs */ + +G_DEFINE_TYPE (MsdA11yKeyboardAtspi, msd_a11y_keyboard_atspi, G_TYPE_OBJECT) + +static void +msd_a11y_keyboard_atspi_class_init (MsdA11yKeyboardAtspiClass *klass G_GNUC_UNUSED) +{ +} + +static void +msd_a11y_keyboard_atspi_init (MsdA11yKeyboardAtspi *self G_GNUC_UNUSED) +{ +} + +void +msd_a11y_keyboard_atspi_start (MsdA11yKeyboardAtspi *self G_GNUC_UNUSED) +{ +} + +void +msd_a11y_keyboard_atspi_stop (MsdA11yKeyboardAtspi *self G_GNUC_UNUSED) +{ +} + +#endif /* ! defined(HAVE_LIBATSPI) */ + +MsdA11yKeyboardAtspi * +msd_a11y_keyboard_atspi_new () +{ + return g_object_new (MSD_TYPE_A11Y_KEYBOARD_ATSPI, NULL); +} -- cgit v1.2.1