[gtk+] wayland: Don't round trip recursively during initialization

[Jonas Ådahl <jadahl src gnome org>]

commit 181e4399f6e2588b462eaa5689bdebd4063d8a6f
Author: Jonas Ådahl <jadahl gmail com>
Date:   Mon May 18 16:02:45 2015 +0800

    wayland: Don't round trip recursively during initialization
    
    Instead use asynchronous round trips that is synchronized in the end of
    the initialization. This makes it easier to track state, as we won't
    dispatch arbitrary Wayland messages while processing globals.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=719819

 gdk/wayland/gdkdisplay-wayland.c |   50 ++++++++++++++++++++++++++++++++++---
 gdk/wayland/gdkdisplay-wayland.h |    2 +
 2 files changed, 48 insertions(+), 4 deletions(-)
---
diff --git a/gdk/wayland/gdkdisplay-wayland.c b/gdk/wayland/gdkdisplay-wayland.c
index 6df25cf..8e23afe 100644
--- a/gdk/wayland/gdkdisplay-wayland.c
+++ b/gdk/wayland/gdkdisplay-wayland.c
@@ -74,6 +74,35 @@ static void _gdk_wayland_display_load_cursor_theme (GdkWaylandDisplay *wayland_d
 G_DEFINE_TYPE (GdkWaylandDisplay, gdk_wayland_display, GDK_TYPE_DISPLAY)
 
 static void
+async_roundtrip_callback (void               *data,
+                          struct wl_callback *callback,
+                          uint32_t            time)
+{
+  GdkWaylandDisplay *display_wayland = data;
+
+  display_wayland->async_roundtrips =
+    g_list_remove (display_wayland->async_roundtrips, callback);
+  wl_callback_destroy (callback);
+}
+
+static const struct wl_callback_listener async_roundrip_listener = {
+  async_roundtrip_callback
+};
+
+static void
+_gdk_wayland_display_async_roundtrip (GdkWaylandDisplay *display_wayland)
+{
+  struct wl_callback *callback;
+
+  callback = wl_display_sync (display_wayland->wl_display);
+  wl_callback_add_listener (callback,
+                            &async_roundrip_listener,
+                            display_wayland);
+  display_wayland->async_roundtrips =
+    g_list_append (display_wayland->async_roundtrips, callback);
+}
+
+static void
 gdk_input_init (GdkDisplay *display)
 {
   GdkWaylandDisplay *display_wayland;
@@ -193,13 +222,13 @@ gdk_registry_handle_global (void               *data,
       output =
         wl_registry_bind (display_wayland->wl_registry, id, &wl_output_interface, MIN (version, 2));
       _gdk_wayland_screen_add_output (display_wayland->screen, id, output, MIN (version, 2));
-      wl_display_roundtrip (display_wayland->wl_display);
+      _gdk_wayland_display_async_roundtrip (display_wayland);
     }
   else if (strcmp (interface, "wl_seat") == 0)
     {
       seat = wl_registry_bind (display_wayland->wl_registry, id, &wl_seat_interface, MIN (version, 4));
       _gdk_wayland_device_manager_add_seat (gdk_display->device_manager, id, seat);
-      wl_display_roundtrip (display_wayland->wl_display);
+      _gdk_wayland_display_async_roundtrip (display_wayland);
     }
   else if (strcmp (interface, "wl_data_device_manager") == 0)
     {
@@ -273,8 +302,18 @@ _gdk_wayland_display_open (const gchar *display_name)
   display_wayland->wl_registry = wl_display_get_registry (display_wayland->wl_display);
   wl_registry_add_listener (display_wayland->wl_registry, &registry_listener, display_wayland);
 
-  /* Wait until the dust has settled during init... */
-  wl_display_roundtrip (display_wayland->wl_display);
+  _gdk_wayland_display_async_roundtrip (display_wayland);
+
+  /* Wait for initializing to complete. This means waiting for all
+   * asynchrounous roundtrips that were triggered during initial roundtrip. */
+  while (g_list_length (display_wayland->async_roundtrips) > 0)
+    {
+      if (wl_display_dispatch (display_wayland->wl_display) < 0)
+        {
+          g_object_unref (display);
+          return NULL;
+        }
+    }
 
   gdk_input_init (display);
 
@@ -308,6 +347,9 @@ gdk_wayland_display_dispose (GObject *object)
       display_wayland->selection = NULL;
     }
 
+  g_list_foreach (display_wayland->async_roundtrips,
+                  (GFunc) wl_callback_destroy, NULL);
+
   G_OBJECT_CLASS (gdk_wayland_display_parent_class)->dispose (object);
 }
 
diff --git a/gdk/wayland/gdkdisplay-wayland.h b/gdk/wayland/gdkdisplay-wayland.h
index 781be51..957a89a 100644
--- a/gdk/wayland/gdkdisplay-wayland.h
+++ b/gdk/wayland/gdkdisplay-wayland.h
@@ -72,6 +72,8 @@ struct _GdkWaylandDisplay
   struct wl_data_device_manager *data_device_manager;
   struct wl_subcompositor *subcompositor;
 
+  GList *async_roundtrips;
+
   struct wl_cursor_theme *scaled_cursor_themes[GDK_WAYLAND_THEME_SCALES_COUNT];
   gchar *cursor_theme_name;
   int cursor_theme_size;