a11y-keyboard: Add support for ringing the bell when CapsLock is active

6 files changed, 357 insertions, 1 deletions

diff --git a/plugins/a11y-keyboard/Makefile.am b/plugins/a11y-keyboard/Makefile.am
index 0881088..92072e2 100644
--- a/plugins/a11y-keyboard/Makefile.am
+++ b/plugins/a11y-keyboard/Makefile.am
@@ -42,6 +42,8 @@ liba11y_keyboard_la_SOURCES = 		\
 	msd-a11y-keyboard-plugin.c	\
 	msd-a11y-keyboard-manager.h	\
 	msd-a11y-keyboard-manager.c	\
+	msd-a11y-keyboard-atspi.h	\
+	msd-a11y-keyboard-atspi.c	\
 	msd-a11y-preferences-dialog.h	\
 	msd-a11y-preferences-dialog.c	\
 	$(NULL)
@@ -55,6 +57,7 @@ liba11y_keyboard_la_CPPFLAGS = \
 liba11y_keyboard_la_CFLAGS =		\
 	$(SETTINGS_PLUGIN_CFLAGS)	\
 	$(LIBNOTIFY_CFLAGS)		\
+	$(LIBATSPI_CFLAGS)		\
 	$(AM_CFLAGS)			\
 	$(WARN_CFLAGS)			\
 	$(NULL)
@@ -66,6 +69,7 @@ liba11y_keyboard_la_LDFLAGS = 		\
 liba11y_keyboard_la_LIBADD  = 		\
 	$(SETTINGS_PLUGIN_LIBS)		\
 	$(LIBNOTIFY_LIBS)		\
+	$(LIBATSPI_LIBS)		\
 	$(NULL)
 
 plugin_in_files = 		\
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 <[email protected]>
+ *
+ * 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 <glib-object.h>
+
+#ifdef HAVE_LIBATSPI
+#include <gdk/gdk.h>
+#include <atspi/atspi.h>
+
+
+/* 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);
+}
diff --git a/plugins/a11y-keyboard/msd-a11y-keyboard-atspi.h b/plugins/a11y-keyboard/msd-a11y-keyboard-atspi.h
new file mode 100644
index 0000000..32fc0e7
--- /dev/null
+++ b/plugins/a11y-keyboard/msd-a11y-keyboard-atspi.h
@@ -0,0 +1,55 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*-
+ *
+ * Copyright (C) 2020 Colomban Wendling <[email protected]>
+ *
+ * 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.
+ */
+
+#ifndef __MSD_A11Y_KEYBOARD_ATSPI_H
+#define __MSD_A11Y_KEYBOARD_ATSPI_H
+
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+#define MSD_TYPE_A11Y_KEYBOARD_ATSPI            (msd_a11y_keyboard_atspi_get_type ())
+#define MSD_A11Y_KEYBOARD_ATSPI(o)              (G_TYPE_CHECK_INSTANCE_CAST ((o), MSD_TYPE_A11Y_KEYBOARD_ATSPI, MsdA11yKeyboardAtspi))
+#define MSD_A11Y_KEYBOARD_ATSPI_CLASS(k)        (G_TYPE_CHECK_CLASS_CAST((k), MSD_TYPE_A11Y_KEYBOARD_ATSPI, MsdA11yKeyboardAtspiClass))
+#define MSD_IS_A11Y_KEYBOARD_ATSPI(o)           (G_TYPE_CHECK_INSTANCE_TYPE ((o), MSD_TYPE_A11Y_KEYBOARD_ATSPI))
+#define MSD_IS_A11Y_KEYBOARD_ATSPI_CLASS(k)     (G_TYPE_CHECK_CLASS_TYPE ((k), MSD_TYPE_A11Y_KEYBOARD_ATSPI))
+#define MSD_A11Y_KEYBOARD_ATSPI_GET_CLASS(o)    (G_TYPE_INSTANCE_GET_CLASS ((o), MSD_TYPE_A11Y_KEYBOARD_ATSPI, MsdA11yKeyboardAtspiClass))
+
+typedef struct MsdA11yKeyboardAtspiPrivate MsdA11yKeyboardAtspiPrivate;
+
+typedef struct
+{
+        GObject                         parent;
+        MsdA11yKeyboardAtspiPrivate    *priv;
+} MsdA11yKeyboardAtspi;
+
+typedef struct
+{
+        GObjectClass   parent_class;
+} MsdA11yKeyboardAtspiClass;
+
+GType                   msd_a11y_keyboard_atspi_get_type        (void);
+
+MsdA11yKeyboardAtspi   *msd_a11y_keyboard_atspi_new             (void);
+void                    msd_a11y_keyboard_atspi_start           (MsdA11yKeyboardAtspi *self);
+void                    msd_a11y_keyboard_atspi_stop            (MsdA11yKeyboardAtspi *self);
+
+G_END_DECLS
+
+#endif
diff --git a/plugins/a11y-keyboard/msd-a11y-keyboard-manager.c b/plugins/a11y-keyboard/msd-a11y-keyboard-manager.c
index 57ce388..67a690b 100644
--- a/plugins/a11y-keyboard/msd-a11y-keyboard-manager.c
+++ b/plugins/a11y-keyboard/msd-a11y-keyboard-manager.c
@@ -49,9 +49,11 @@
 
 #include "mate-settings-profile.h"
 #include "msd-a11y-keyboard-manager.h"
+#include "msd-a11y-keyboard-atspi.h"
 #include "msd-a11y-preferences-dialog.h"
 
 #define CONFIG_SCHEMA "org.mate.accessibility-keyboard"
+#define KEY_CAPSLOCK_BEEP_ENABLED "capslock-beep-enable"
 #define NOTIFICATION_TIMEOUT 30
 
 struct MsdA11yKeyboardManagerPrivate
@@ -64,6 +66,7 @@ struct MsdA11yKeyboardManagerPrivate
         GtkWidget *preferences_dialog;
         GtkStatusIcon *status_icon;
         XkbDescRec *original_xkb_desc;
+        MsdA11yKeyboardAtspi *capslock_beep;
 
         GSettings  *settings;
 
@@ -984,6 +987,17 @@ keyboard_callback (GSettings              *settings,
         maybe_show_status_icon (manager);
 }
 
+static void
+capslock_beep_callback (GSettings              *settings,
+                        gchar                  *key G_GNUC_UNUSED,
+                        MsdA11yKeyboardManager *manager)
+{
+        if (g_settings_get_boolean (settings, KEY_CAPSLOCK_BEEP_ENABLED))
+                msd_a11y_keyboard_atspi_start (manager->priv->capslock_beep);
+        else
+                msd_a11y_keyboard_atspi_stop (manager->priv->capslock_beep);
+}
+
 static gboolean
 start_a11y_keyboard_idle_cb (MsdA11yKeyboardManager *manager)
 {
@@ -992,10 +1006,17 @@ start_a11y_keyboard_idle_cb (MsdA11yKeyboardManager *manager)
         g_debug ("Starting a11y_keyboard manager");
         mate_settings_profile_start (NULL);
 
+        manager->priv->settings = g_settings_new (CONFIG_SCHEMA);
+
+        manager->priv->capslock_beep = msd_a11y_keyboard_atspi_new ();
+        if (g_settings_get_boolean (manager->priv->settings, KEY_CAPSLOCK_BEEP_ENABLED))
+                msd_a11y_keyboard_atspi_start (manager->priv->capslock_beep);
+        g_signal_connect (manager->priv->settings, "changed::"KEY_CAPSLOCK_BEEP_ENABLED,
+                          G_CALLBACK (capslock_beep_callback), manager);
+
         if (!xkb_enabled (manager))
                 goto out;
 
-        manager->priv->settings = g_settings_new (CONFIG_SCHEMA);
         g_signal_connect (manager->priv->settings, "changed", G_CALLBACK (keyboard_callback), manager);
 
         set_devicepresence_handler (manager);
@@ -1104,6 +1125,8 @@ msd_a11y_keyboard_manager_stop (MsdA11yKeyboardManager *manager)
 
         p->slowkeys_shortcut_val = FALSE;
         p->stickykeys_shortcut_val = FALSE;
+
+        g_clear_object (&p->capslock_beep);
 }
 
 static void
diff --git a/plugins/a11y-keyboard/msd-a11y-preferences-dialog.c b/plugins/a11y-keyboard/msd-a11y-preferences-dialog.c
index fa6d426..69cf418 100644
--- a/plugins/a11y-keyboard/msd-a11y-preferences-dialog.c
+++ b/plugins/a11y-keyboard/msd-a11y-preferences-dialog.c
@@ -49,6 +49,7 @@
 #define KEY_BOUNCE_KEYS_ENABLED      "bouncekeys-enable"
 #define KEY_SLOW_KEYS_ENABLED        "slowkeys-enable"
 #define KEY_MOUSE_KEYS_ENABLED       "mousekeys-enable"
+#define KEY_CAPSLOCK_BEEP_ENABLED    "capslock-beep-enable"
 
 #define KEY_AT_SCHEMA                   "org.mate.applications-at"
 #define KEY_AT_SCREEN_KEYBOARD_ENABLED  "screen-keyboard-enabled"
@@ -91,6 +92,7 @@ struct MsdA11yPreferencesDialogPrivate
         GtkWidget *sticky_keys_checkbutton;
         GtkWidget *slow_keys_checkbutton;
         GtkWidget *bounce_keys_checkbutton;
+        GtkWidget *capslock_beep_checkbutton;
 
         GtkWidget *large_print_checkbutton;
         GtkWidget *high_contrast_checkbutton;
@@ -323,6 +325,18 @@ config_set_slow_keys (MsdA11yPreferencesDialog *dialog, gboolean enabled)
 }
 
 static gboolean
+config_get_capslock_beep (MsdA11yPreferencesDialog *dialog, gboolean *is_writable)
+{
+        return config_get_bool (dialog->priv->settings_a11y, KEY_CAPSLOCK_BEEP_ENABLED, is_writable);
+}
+
+static void
+config_set_capslock_beep (MsdA11yPreferencesDialog *dialog, gboolean enabled)
+{
+        g_settings_set_boolean (dialog->priv->settings_a11y, KEY_CAPSLOCK_BEEP_ENABLED, enabled);
+}
+
+static gboolean
 config_have_at_gsettings_condition (const char *condition)
 {
         DBusGProxy      *sm_proxy;
@@ -422,6 +436,13 @@ on_slow_keys_checkbutton_toggled (GtkToggleButton          *button,
 }
 
 static void
+on_capslock_beep_checkbutton_toggled (GtkToggleButton          *button,
+                                      MsdA11yPreferencesDialog *dialog)
+{
+        config_set_capslock_beep (dialog, gtk_toggle_button_get_active (button));
+}
+
+static void
 on_high_contrast_checkbutton_toggled (GtkToggleButton          *button,
                                       MsdA11yPreferencesDialog *dialog)
 {
@@ -493,6 +514,18 @@ ui_set_slow_keys (MsdA11yPreferencesDialog *dialog,
 }
 
 static void
+ui_set_capslock_beep (MsdA11yPreferencesDialog *dialog,
+                      gboolean                  enabled)
+{
+        gboolean active;
+
+        active = gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON (dialog->priv->capslock_beep_checkbutton));
+        if (active != enabled) {
+                gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (dialog->priv->capslock_beep_checkbutton), enabled);
+        }
+}
+
+static void
 ui_set_high_contrast (MsdA11yPreferencesDialog *dialog,
                       gboolean                  enabled)
 {
@@ -569,6 +602,10 @@ key_changed_cb (GSettings                *settings,
                 gboolean enabled;
                 enabled = g_settings_get_boolean (settings, key);
                 ui_set_slow_keys (dialog, enabled);
+        } else if (g_strcmp0 (key, KEY_CAPSLOCK_BEEP_ENABLED) == 0) {
+                gboolean enabled;
+                enabled = g_settings_get_boolean (settings, key);
+                ui_set_capslock_beep (dialog, enabled);
         } else if (g_strcmp0 (key, KEY_AT_SCREEN_READER_ENABLED) == 0) {
                 gboolean enabled;
                 enabled = g_settings_get_boolean (settings, key);
@@ -634,6 +671,19 @@ setup_dialog (MsdA11yPreferencesDialog *dialog,
         }
 
         widget = GTK_WIDGET (gtk_builder_get_object (builder,
+                                                     "capslock_beep_checkbutton"));
+        dialog->priv->capslock_beep_checkbutton = widget;
+        g_signal_connect (widget,
+                          "toggled",
+                          G_CALLBACK (on_capslock_beep_checkbutton_toggled),
+                          dialog);
+        enabled = config_get_capslock_beep (dialog, &is_writable);
+        ui_set_capslock_beep (dialog, enabled);
+        if (! is_writable) {
+                gtk_widget_set_sensitive (widget, FALSE);
+        }
+
+        widget = GTK_WIDGET (gtk_builder_get_object (builder,
                                                      "high_contrast_checkbutton"));
         dialog->priv->high_contrast_checkbutton = widget;
         g_signal_connect (widget,
diff --git a/plugins/a11y-keyboard/msd-a11y-preferences-dialog.ui b/plugins/a11y-keyboard/msd-a11y-preferences-dialog.ui
index 29b8015..5ed30ff 100644
--- a/plugins/a11y-keyboard/msd-a11y-preferences-dialog.ui
+++ b/plugins/a11y-keyboard/msd-a11y-preferences-dialog.ui
@@ -209,6 +209,22 @@
                     <property name="position">7</property>
                   </packing>
                 </child>
+                <child>
+                  <object class="GtkCheckButton" id="capslock_beep_checkbutton">
+                    <property name="label" translatable="yes">_Beep when pressing a key while CapsLock is active</property>
+                    <property name="visible">True</property>
+                    <property name="can_focus">True</property>
+                    <property name="receives_default">False</property>
+                    <property name="events">GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK | GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK</property>
+                    <property name="use_underline">True</property>
+                    <property name="draw_indicator">True</property>
+                  </object>
+                  <packing>
+                    <property name="expand">True</property>
+                    <property name="fill">True</property>
+                    <property name="position">8</property>
+                  </packing>
+                </child>
               </object>
               <packing>
                 <property name="expand">False</property>