clutter/evdev: Implement ClutterVirtualInputDevice::notify_keyval

This is somewhat gross at the moment, because we're after all mimicking
real keyboard events, we can only lookup keycodes that are available
in the current map, and the control of levels is rather limited.

Eventually, we want to implement the text_input protocol, handle these
events separately to MetaWaylandKeyboard, so event->key.keyval is
is guaranteed to be the final result. Until then, this is the farthest
we can get.

https://bugzilla.gnome.org/show_bug.cgi?id=765009

clutter/clutter/evdev/clutter-virtual-input-device-evdev.c

@@ -245,6 +245,143 @@ clutter_virtual_input_device_evdev_notify_key (ClutterVirtualInputDevice *virtua
                                  TRUE);
 }
 
+static gboolean
+pick_keycode_for_keyval_in_current_group (ClutterVirtualInputDevice *virtual_device,
+                                          guint                      keyval,
+                                          guint                     *keycode_out,
+                                          guint                     *level_out)
+{
+  ClutterVirtualInputDeviceEvdev *virtual_evdev =
+    CLUTTER_VIRTUAL_INPUT_DEVICE_EVDEV (virtual_device);
+  ClutterDeviceManager *manager;
+  struct xkb_keymap *xkb_keymap;
+  struct xkb_state  *state;
+  guint keycode, layout;
+  xkb_keycode_t min_keycode, max_keycode;
+
+  manager = clutter_virtual_input_device_get_manager (virtual_device);
+  xkb_keymap = _clutter_device_manager_evdev_get_keymap (CLUTTER_DEVICE_MANAGER_EVDEV (manager));
+  state = virtual_evdev->seat->xkb;
+
+  layout = xkb_state_serialize_layout (state, XKB_STATE_LAYOUT_EFFECTIVE);
+  min_keycode = xkb_keymap_min_keycode (xkb_keymap);
+  max_keycode = xkb_keymap_max_keycode (xkb_keymap);
+  for (keycode = min_keycode; keycode < max_keycode; keycode++)
+    {
+      gint num_levels, level;
+      num_levels = xkb_keymap_num_levels_for_key (xkb_keymap, keycode, layout);
+      for (level = 0; level < num_levels; level++)
+        {
+          const xkb_keysym_t *syms;
+          gint num_syms, sym;
+          num_syms = xkb_keymap_key_get_syms_by_level (xkb_keymap, keycode, layout, level, &syms);
+          for (sym = 0; sym < num_syms; sym++)
+            {
+              if (syms[sym] == keyval)
+                {
+                  *keycode_out = keycode;
+                  if (level_out)
+                    *level_out = level;
+                  return TRUE;
+                }
+            }
+        }
+    }
+
+  return FALSE;
+}
+
+static void
+apply_level_modifiers (ClutterVirtualInputDevice *virtual_device,
+                       uint64_t                   time_us,
+                       uint32_t                   level,
+                       uint32_t                   key_state)
+{
+  ClutterVirtualInputDeviceEvdev *virtual_evdev =
+    CLUTTER_VIRTUAL_INPUT_DEVICE_EVDEV (virtual_device);
+  guint keysym, keycode, evcode;
+
+  if (level == 0)
+    return;
+
+  if (level == 1)
+    {
+      keysym = XKB_KEY_Shift_L;
+    }
+  else if (level == 2)
+    {
+      keysym = XKB_KEY_ISO_Level3_Shift;
+    }
+  else
+    {
+      g_warning ("Unhandled level: %d\n", level);
+      return;
+    }
+
+  if (!pick_keycode_for_keyval_in_current_group (virtual_device, keysym,
+                                                 &keycode, NULL))
+    return;
+
+  clutter_input_device_keycode_to_evdev (virtual_evdev->device,
+                                         keycode, &evcode);
+  clutter_seat_evdev_notify_key (virtual_evdev->seat,
+                                 virtual_evdev->device,
+                                 time_us,
+                                 evcode,
+                                 key_state,
+                                 TRUE);
+}
+
+static void
+clutter_virtual_input_device_evdev_notify_keyval (ClutterVirtualInputDevice *virtual_device,
+                                                  uint64_t                   time_us,
+                                                  uint32_t                   keyval,
+                                                  ClutterKeyState            key_state)
+{
+  ClutterVirtualInputDeviceEvdev *virtual_evdev =
+    CLUTTER_VIRTUAL_INPUT_DEVICE_EVDEV (virtual_device);
+  int key_count;
+  guint keycode = 0, level = 0, evcode = 0;
+
+  if (!pick_keycode_for_keyval_in_current_group (virtual_device,
+                                                 keyval, &keycode, &level))
+    {
+      g_warning ("No keycode found for keyval %x in current group", keyval);
+      return;
+    }
+
+  clutter_input_device_keycode_to_evdev (virtual_evdev->device,
+                                         keycode, &evcode);
+
+  if (get_button_type (evcode) != EVDEV_BUTTON_TYPE_KEY)
+    {
+      g_warning ("Unknown/invalid virtual device key 0x%x pressed\n", evcode);
+      return;
+    }
+
+  key_count = update_button_count (virtual_evdev, evcode, key_state);
+  if (key_count < 0 || key_count > 1)
+    {
+      g_warning ("Received multiple virtual 0x%x key %s (ignoring)", keycode,
+		 key_state == CLUTTER_KEY_STATE_PRESSED ? "presses" : "releases");
+      update_button_count (virtual_evdev, evcode, 1 - key_state);
+      return;
+    }
+
+  if (key_state)
+    apply_level_modifiers (virtual_device, time_us, level, key_state);
+
+  clutter_seat_evdev_notify_key (virtual_evdev->seat,
+                                 virtual_evdev->device,
+                                 time_us,
+                                 evcode,
+                                 key_state,
+                                 TRUE);
+
+  if (!key_state)
+    apply_level_modifiers (virtual_device, time_us, level, key_state);
+}
+
 static void
 clutter_virtual_input_device_evdev_get_property (GObject    *object,
                                                  guint       prop_id,
@@ -347,6 +484,7 @@ clutter_virtual_input_device_evdev_class_init (ClutterVirtualInputDeviceEvdevCla
   virtual_input_device_class->notify_absolute_motion = clutter_virtual_input_device_evdev_notify_absolute_motion;
   virtual_input_device_class->notify_button = clutter_virtual_input_device_evdev_notify_button;
   virtual_input_device_class->notify_key = clutter_virtual_input_device_evdev_notify_key;
+  virtual_input_device_class->notify_keyval = clutter_virtual_input_device_evdev_notify_keyval;
 
   obj_props[PROP_SEAT] = g_param_spec_pointer ("seat",
                                                P_("ClutterSeatEvdev"),