[gtk+] wayland: use g_signal_handler_disconnect()

[Christian Hergert <chergert src gnome org>]

commit ebb894cd64a84ec99da493622132821740ff91ee
Author: Christian Hergert <chergert redhat com>
Date:   Fri May 6 11:31:41 2016 +0300

    wayland: use g_signal_handler_disconnect()
    
    Use of g_signal_handlers_disconnect_by_func() needs to do more work than
    necessary to find all the matching handlers. Instead, just hold on to the
    signal identifier and remove it directly so we hit the fast path.
    
    Not terribly ground breaking in terms of performance gains, but its done
    enough to be worthwhile.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=766049

 gdk/wayland/gdkwindow-wayland.c |   24 +++++++++++++++---------
 1 files changed, 15 insertions(+), 9 deletions(-)
---
diff --git a/gdk/wayland/gdkwindow-wayland.c b/gdk/wayland/gdkwindow-wayland.c
index eac2e22..3b70318 100644
--- a/gdk/wayland/gdkwindow-wayland.c
+++ b/gdk/wayland/gdkwindow-wayland.c
@@ -161,6 +161,8 @@ struct _GdkWindowImplWayland
 
   int saved_width;
   int saved_height;
+
+  gulong parent_surface_committed_handler;
 };
 
 struct _GdkWindowImplWaylandClass
@@ -1144,9 +1146,9 @@ on_parent_surface_committed (GdkWindowImplWayland *parent_impl,
 {
   GdkWindowImplWayland *impl = GDK_WINDOW_IMPL_WAYLAND (window->impl);
 
-  g_signal_handlers_disconnect_by_func (parent_impl,
-                                        (gpointer) on_parent_surface_committed,
-                                        window);
+  g_signal_handler_disconnect (parent_impl,
+                               impl->parent_surface_committed_handler);
+  impl->parent_surface_committed_handler = 0;
 
   wl_subsurface_set_desync (impl->display_server.wl_subsurface);
 }
@@ -1180,9 +1182,10 @@ gdk_wayland_window_create_subsurface (GdkWindow *window)
        * content, wait with making the subsurface desynchronized until after
        * the parent was committed.
        */
-      g_signal_connect_object (parent_impl, "committed",
-                               G_CALLBACK (on_parent_surface_committed),
-                               window, 0);
+      impl->parent_surface_committed_handler =
+        g_signal_connect_object (parent_impl, "committed",
+                                 G_CALLBACK (on_parent_surface_committed),
+                                 window, 0);
       gdk_window_request_transient_parent_commit (window);
     }
 }
@@ -1761,9 +1764,12 @@ unmap_subsurface (GdkWindow *window)
 
   parent_impl = GDK_WINDOW_IMPL_WAYLAND (impl->transient_for->impl);
   wl_subsurface_destroy (impl->display_server.wl_subsurface);
-  g_signal_handlers_disconnect_by_func (parent_impl,
-                                        (gpointer) on_parent_surface_committed,
-                                        window);
+  if (impl->parent_surface_committed_handler)
+    {
+      g_signal_handler_disconnect (parent_impl,
+                                   impl->parent_surface_committed_handler);
+      impl->parent_surface_committed_handler = 0;
+    }
   impl->display_server.wl_subsurface = NULL;
 }