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

2 files changed, 48 insertions, 4 deletions

diff --git a/gdk/wayland/gdkdisplay-wayland.c b/gdk/wayland/gdkdisplay-wayland.c
index 6df25cff06..8e23afe96b 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 781be518ef..957a89a774 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;