[gtk+] iconview: Avoid usage of gdk_window_get_device_position() during DnD

[Carlos Garnacho <carlosg src gnome org>]

commit 61cc10760d84f8600b6faf11046bb7b9a276e942
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu May 21 14:16:13 2015 +0200

    iconview: Avoid usage of gdk_window_get_device_position() during DnD
    
    Just use the last coordinates given on XdndPosition/drag_motion() in
    order to trigger scrolling.
    
    When running on Xwayland, the pointer position is unknown at this
    stage on the X11 side, so the coordinates given here are bogus.
    This change avoids both roundtrips and this situation.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=749679

 gtk/gtkiconview.c |   32 +++++++++-----------------------
 1 files changed, 9 insertions(+), 23 deletions(-)
---
diff --git a/gtk/gtkiconview.c b/gtk/gtkiconview.c
index f11fed1..705356d 100644
--- a/gtk/gtkiconview.c
+++ b/gtk/gtkiconview.c
@@ -6208,8 +6208,7 @@ remove_scroll_timeout (GtkIconView *icon_view)
 }
 
 static void
-gtk_icon_view_autoscroll (GtkIconView *icon_view,
-                          GdkDevice   *device)
+gtk_icon_view_autoscroll (GtkIconView *icon_view)
 {
   GdkWindow *window;
   gint px, py, width, height;
@@ -6217,7 +6216,8 @@ gtk_icon_view_autoscroll (GtkIconView *icon_view,
 
   window = gtk_widget_get_window (GTK_WIDGET (icon_view));
 
-  gdk_window_get_device_position (window, device, &px, &py, NULL);
+  px = icon_view->priv->event_last_x;
+  py = icon_view->priv->event_last_y;
   gdk_window_get_geometry (window, NULL, NULL, &width, &height);
 
   /* see if we are near the edge. */
@@ -6238,27 +6238,14 @@ gtk_icon_view_autoscroll (GtkIconView *icon_view,
                               gtk_adjustment_get_value (icon_view->priv->hadjustment) + hoffset);
 }
 
-typedef struct {
-  GtkIconView *icon_view;
-  GdkDevice   *device;
-} DragScrollData;
-
 static gboolean
-drag_scroll_timeout (gpointer datap)
+drag_scroll_timeout (gpointer data)
 {
-  DragScrollData *data = datap;
-
-  gtk_icon_view_autoscroll (data->icon_view, data->device);
+  gtk_icon_view_autoscroll (data);
 
   return TRUE;
 }
 
-static void
-drag_scroll_data_free (DragScrollData *data)
-{
-  g_slice_free (DragScrollData, data);
-}
-
 static gboolean
 set_destination (GtkIconView    *icon_view,
                 GdkDragContext *context,
@@ -6638,6 +6625,9 @@ gtk_icon_view_drag_motion (GtkWidget      *widget,
   if (!set_destination (icon_view, context, x, y, &suggested_action, &target))
     return FALSE;
 
+  icon_view->priv->event_last_x = x;
+  icon_view->priv->event_last_y = y;
+
   gtk_icon_view_get_drag_dest_item (icon_view, &path, &pos);
 
   /* we only know this *after* set_desination_row */
@@ -6652,12 +6642,8 @@ gtk_icon_view_drag_motion (GtkWidget      *widget,
     {
       if (icon_view->priv->scroll_timeout_id == 0)
        {
-          DragScrollData *data = g_slice_new (DragScrollData);
-          data->icon_view = icon_view;
-          data->device = gdk_drag_context_get_device (context);
-
          icon_view->priv->scroll_timeout_id =
-           gdk_threads_add_timeout_full (G_PRIORITY_DEFAULT, 50, drag_scroll_timeout, data, (GDestroyNotify) 
drag_scroll_data_free);
+           gdk_threads_add_timeout (50, drag_scroll_timeout, icon_view);
          g_source_set_name_by_id (icon_view->priv->scroll_timeout_id, "[gtk+] drag_scroll_timeout");
        }