[mutter/wip/carlosg/device-capabilities] backends: Set mapping function for left-handed setting

[Carlos Garnacho <carlosg src gnome org>]

commit 8e27195bebd90c6aba2e669f4c3e7da8eb1e78aa
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Mar 9 12:19:20 2022 +0100

    backends: Set mapping function for left-handed setting
    
    We have separate left-handed settings for mice and touchpads,
    which are slightly harder to be kept separate querying devices
    by capabilities. These should just relate if the "follow mouse"
    handedness is set on touchpads.
    
    In order to keep applying the setting in a fine grained manner,
    add a mapping function for the left-handed setting on mice, this
    will replace the right configuration value depending on the pointer
    device it is dealing with.
    
    This ensures mouse preferences don't overwrite touchpad behavior
    unless that preference is enabled.

 src/backends/meta-input-settings.c | 45 +++++++++++++++++++++++++++++---------
 1 file changed, 35 insertions(+), 10 deletions(-)
---
diff --git a/src/backends/meta-input-settings.c b/src/backends/meta-input-settings.c
index d045315fa7..a2a6e6230f 100644
--- a/src/backends/meta-input-settings.c
+++ b/src/backends/meta-input-settings.c
@@ -281,6 +281,39 @@ update_touchpad_left_handed (MetaInputSettings  *input_settings,
     }
 }
 
+static gboolean
+apply_device_handedness (MetaInputSettings  *input_settings,
+                         ClutterInputDevice *device,
+                         gboolean            value)
+{
+  if ((clutter_input_device_get_capabilities (device) &
+       CLUTTER_INPUT_CAPABILITY_TOUCHPAD) != 0)
+    {
+      GDesktopTouchpadHandedness handedness;
+      MetaInputSettingsPrivate *priv;
+
+      /* Look up correct handedness on touchpads */
+      priv = meta_input_settings_get_instance_private (input_settings);
+      handedness = g_settings_get_enum (priv->touchpad_settings, "left-handed");
+
+      switch (handedness)
+        {
+        case G_DESKTOP_TOUCHPAD_HANDEDNESS_RIGHT:
+          value = FALSE;
+          break;
+        case G_DESKTOP_TOUCHPAD_HANDEDNESS_LEFT:
+          value = TRUE;
+          break;
+        case G_DESKTOP_TOUCHPAD_HANDEDNESS_MOUSE:
+          break;
+        default:
+          g_assert_not_reached ();
+        }
+    }
+
+  return value;
+}
+
 static void
 update_mouse_left_handed (MetaInputSettings  *input_settings,
                           ClutterInputDevice *device)
@@ -312,19 +345,11 @@ update_mouse_left_handed (MetaInputSettings  *input_settings,
     }
   else
     {
-      GDesktopTouchpadHandedness touchpad_handedness;
-
       settings_set_bool_setting (input_settings,
-                                 CLUTTER_INPUT_CAPABILITY_POINTER, NULL,
+                                 CLUTTER_INPUT_CAPABILITY_POINTER,
+                                 apply_device_handedness,
                                  input_settings_class->set_left_handed,
                                  enabled);
-
-      touchpad_handedness = g_settings_get_enum (priv->touchpad_settings,
-                                                 "left-handed");
-
-      /* Also update touchpads if they're following mouse settings */
-      if (touchpad_handedness == G_DESKTOP_TOUCHPAD_HANDEDNESS_MOUSE)
-        update_touchpad_left_handed (input_settings, NULL);
     }
 }