wayland: Create internal GdkWindow to be set as the DnD source

During drag operations from another client, we currently set no window as
the DnD source. There's paths in upper layers though that rely on it being
set, just that we don't trigger these yet.

diff --git a/gdk/wayland/gdkdevice-wayland.c b/gdk/wayland/gdkdevice-wayland.c
index a22351b4d7b2d8091b01e06a3124e9c2fd312c70..070837260a4a85a100f38fc22cd366b7a2b3f24e 100644 (file)
--- a/gdk/wayland/gdkdevice-wayland.c
+++ b/gdk/wayland/gdkdevice-wayland.c
@@ -95,6 +95,9 @@ struct _GdkWaylandDeviceData
   struct wl_surface *pointer_surface;
   guint current_output_scale;
   GSList *pointer_surface_outputs;
+
+  /* Source/dest for non-local dnd */
+  GdkWindow *foreign_dnd_window;
 };
 
 struct _GdkWaylandDevice
@@ -623,8 +626,10 @@ data_device_enter (void                  *data,
 
   dnd_owner = gdk_selection_owner_get_for_display (device->display, gdk_drag_get_selection (device->drop_context));
 
-  if (dnd_owner)
-    _gdk_wayland_drag_context_set_source_window (device->drop_context, dnd_owner);
+  if (!dnd_owner)
+    dnd_owner = device->foreign_dnd_window;
+
+  _gdk_wayland_drag_context_set_source_window (device->drop_context, dnd_owner);
 
   _gdk_wayland_drag_context_set_dest_window (device->drop_context,
                                              dest_window, serial);
@@ -1838,6 +1843,26 @@ static const struct wl_surface_listener pointer_surface_listener = {
   pointer_surface_leave
 };
 
+static GdkWindow *
+create_foreign_dnd_window (GdkDisplay *display)
+{
+  GdkWindowAttr attrs;
+  GdkScreen *screen;
+  guint mask;
+
+  screen = gdk_display_get_default_screen (display);
+
+  attrs.x = attrs.y = 0;
+  attrs.width = attrs.height = 1;
+  attrs.wclass = GDK_INPUT_OUTPUT;
+  attrs.window_type = GDK_WINDOW_TEMP;
+  attrs.visual = gdk_screen_get_system_visual (screen);
+
+  mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL;
+
+  return gdk_window_new (gdk_screen_get_root_window (screen), &attrs, mask);
+}
+
 void
 _gdk_wayland_device_manager_add_seat (GdkDeviceManager *device_manager,
                                       guint32           id,
@@ -1857,6 +1882,7 @@ _gdk_wayland_device_manager_add_seat (GdkDeviceManager *device_manager,
   device->device_manager = device_manager;
   device->touches = g_hash_table_new_full (NULL, NULL, NULL,
                                            (GDestroyNotify) g_free);
+  device->foreign_dnd_window = create_foreign_dnd_window (display);
   device->wl_seat = wl_seat;
 
   wl_seat_add_listener (device->wl_seat, &seat_listener, device);
@@ -1898,6 +1924,7 @@ _gdk_wayland_device_manager_remove_seat (GdkDeviceManager *manager,
           /* FIXME: destroy data_device */
           g_clear_object (&device->keyboard_settings);
           g_hash_table_destroy (device->touches);
+          gdk_window_destroy (device->foreign_dnd_window);
           g_free (device);
 
           break;