Implements disable-while-typing in mutter.

Disable-while-typing disables the touchpad while the user is typing.

This patch introduces the necessary backend code to implement the
org.gnome.desktop.peripherals.touchpad.disable-while-typing setting of
gsettings-desktop-schemas which was implemented in commit
4c5b1c1df399d6afaaccb237e299ccd1d5d29ddd and released as part of 3.24.
This is known as dwt in libinput.

This patch has been tested on X11 and Wayland.

https://bugzilla.gnome.org/show_bug.cgi?id=764852

src/backends/meta-input-settings-private.h

@@ -54,6 +54,9 @@ struct _MetaInputSettingsClass
   void (* set_tap_enabled)   (MetaInputSettings  *settings,
                               ClutterInputDevice *device,
                               gboolean            enabled);
+  void (* set_disable_while_typing) (MetaInputSettings  *settings,
+                                     ClutterInputDevice *device,
+                                     gboolean            enabled);
   void (* set_invert_scroll) (MetaInputSettings  *settings,
                               ClutterInputDevice *device,
                               gboolean            inverted);
@@ -106,7 +109,6 @@ struct _MetaInputSettingsClass
                                   ClutterInputDeviceTool     *tool,
                                   GDesktopStylusButtonAction  primary,
                                   GDesktopStylusButtonAction  secondary);
-
   gboolean (* has_two_finger_scroll) (MetaInputSettings  *settings,
                                       ClutterInputDevice *device);
 };

src/backends/meta-input-settings.c

@@ -442,6 +442,44 @@ update_device_natural_scroll (MetaInputSettings      *input_settings,
     }
 }
 
+static void
+update_touchpad_disable_while_typing (MetaInputSettings  *input_settings,
+                                      ClutterInputDevice *device)
+{
+  GSettings *settings;
+  MetaInputSettingsClass *input_settings_class;
+  MetaInputSettingsPrivate *priv;
+  gboolean enabled;
+  const gchar *key = "disable-while-typing";
+
+  if (device &&
+      clutter_input_device_get_device_type (device) != CLUTTER_TOUCHPAD_DEVICE)
+    return;
+
+  priv = meta_input_settings_get_instance_private (input_settings);
+  input_settings_class = META_INPUT_SETTINGS_GET_CLASS (input_settings);
+  enabled = g_settings_get_boolean (priv->touchpad_settings, key);
+
+  if (device)
+   {
+      settings = get_settings_for_device_type (input_settings,
+                                               clutter_input_device_get_device_type (device));
+
+      if (!settings)
+        return;
+
+      settings_device_set_bool_setting (input_settings, device,
+                                        input_settings_class->set_disable_while_typing,
+                                        enabled);
+    }
+  else
+    {
+      settings_set_bool_setting (input_settings, CLUTTER_TOUCHPAD_DEVICE,
+                                 input_settings_class->set_disable_while_typing,
+                                 enabled);
+    }
+}
+
 static void
 update_touchpad_tap_enabled (MetaInputSettings  *input_settings,
                              ClutterInputDevice *device)
@@ -983,6 +1021,8 @@ meta_input_settings_changed_cb (GSettings  *settings,
         update_device_natural_scroll (input_settings, NULL);
       else if (strcmp (key, "tap-to-click") == 0)
         update_touchpad_tap_enabled (input_settings, NULL);
+      else if (strcmp(key, "disable-while-typing") == 0)
+        update_touchpad_disable_while_typing (input_settings, NULL);
       else if (strcmp (key, "send-events") == 0)
         update_touchpad_send_events (input_settings, NULL);
       else if (strcmp (key, "edge-scrolling-enabled") == 0)
@@ -1228,6 +1268,7 @@ apply_device_settings (MetaInputSettings  *input_settings,
 
   update_touchpad_left_handed (input_settings, device);
   update_touchpad_tap_enabled (input_settings, device);
+  update_touchpad_disable_while_typing (input_settings, device);
   update_touchpad_send_events (input_settings, device);
   update_touchpad_two_finger_scroll (input_settings, device);
   update_touchpad_edge_scroll (input_settings, device);

src/backends/native/meta-input-settings-native.c

@@ -121,6 +121,25 @@ meta_input_settings_native_set_tap_enabled (MetaInputSettings  *settings,
                                             LIBINPUT_CONFIG_TAP_DISABLED);
 }
 
+static void
+meta_input_settings_native_set_disable_while_typing (MetaInputSettings  *settings,
+                                                     ClutterInputDevice *device,
+                                                     gboolean            enabled)
+{
+  struct libinput_device *libinput_device;
+
+  libinput_device = clutter_evdev_input_device_get_libinput_device (device);
+
+  if (!libinput_device)
+    return;
+
+  if (libinput_device_config_dwt_is_available (libinput_device))
+    libinput_device_config_dwt_set_enabled (libinput_device,
+                                            enabled ?
+                                            LIBINPUT_CONFIG_DWT_ENABLED :
+                                            LIBINPUT_CONFIG_DWT_DISABLED);
+}
+
 static void
 meta_input_settings_native_set_invert_scroll (MetaInputSettings  *settings,
                                               ClutterInputDevice *device,
@@ -507,6 +526,7 @@ meta_input_settings_native_class_init (MetaInputSettingsNativeClass *klass)
   input_settings_class->set_scroll_button = meta_input_settings_native_set_scroll_button;
   input_settings_class->set_click_method = meta_input_settings_native_set_click_method;
   input_settings_class->set_keyboard_repeat = meta_input_settings_native_set_keyboard_repeat;
+  input_settings_class->set_disable_while_typing = meta_input_settings_native_set_disable_while_typing;
 
   input_settings_class->set_tablet_mapping = meta_input_settings_native_set_tablet_mapping;
   input_settings_class->set_tablet_keep_aspect = meta_input_settings_native_set_tablet_keep_aspect;

src/backends/x11/meta-input-settings-x11.c

@@ -205,6 +205,17 @@ meta_input_settings_x11_set_left_handed (MetaInputSettings  *settings,
     }
 }
 
+static void
+meta_input_settings_x11_set_disable_while_typing (MetaInputSettings  *settings,
+                                                  ClutterInputDevice *device,
+                                                  gboolean            enabled)
+{
+  guchar value = (enabled) ? 1 : 0;
+
+  change_property (device, "libinput Disable While Typing Enabled",
+                   XA_INTEGER, 8, &value, 1);
+}
+
 static void
 meta_input_settings_x11_set_tap_enabled (MetaInputSettings  *settings,
                                          ClutterInputDevice *device,
@@ -744,6 +755,7 @@ meta_input_settings_x11_class_init (MetaInputSettingsX11Class *klass)
   input_settings_class->set_speed = meta_input_settings_x11_set_speed;
   input_settings_class->set_left_handed = meta_input_settings_x11_set_left_handed;
   input_settings_class->set_tap_enabled = meta_input_settings_x11_set_tap_enabled;
+  input_settings_class->set_disable_while_typing = meta_input_settings_x11_set_disable_while_typing;
   input_settings_class->set_invert_scroll = meta_input_settings_x11_set_invert_scroll;
   input_settings_class->set_edge_scroll = meta_input_settings_x11_set_edge_scroll;
   input_settings_class->set_two_finger_scroll = meta_input_settings_x11_set_two_finger_scroll;