compositor: Make it a GObject

This means we can later use GObject features like signals, subclassing
etc.

Bump glib_req version as per g_clear_handle_id usage.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/385

meson.build

@@ -15,7 +15,7 @@ libmutter_api_version = '@0@'.format(api_version)
 
 # generic version requirements
 fribidi_req = '>= 1.0.0'
-glib_req = '>= 2.53.2'
+glib_req = '>= 2.56'
 gi_req = '>= 0.9.5'
 gtk3_req = '>= 3.19.8'
 gdk_pixbuf_req = '>= 2.0'

src/compositor/compositor-private.h

@@ -13,6 +13,8 @@
 
 struct _MetaCompositor
 {
+  GObject         parent;
+
   MetaDisplay    *display;
 
   guint           pre_paint_func_id;

src/compositor/compositor.c

@@ -86,6 +86,8 @@
 #include "wayland/meta-wayland-private.h"
 #endif
 
+G_DEFINE_TYPE (MetaCompositor, meta_compositor, G_TYPE_OBJECT)
+
 static void
 on_presented (ClutterStage     *stage,
               CoglFrameEvent    event,
@@ -135,33 +137,8 @@ meta_switch_workspace_completed (MetaCompositor *compositor)
 void
 meta_compositor_destroy (MetaCompositor *compositor)
 {
-  g_signal_handler_disconnect (compositor->stage,
-                               compositor->stage_after_paint_id);
-  g_signal_handler_disconnect (compositor->stage,
-                               compositor->stage_presented_id);
-
-  compositor->stage_after_paint_id = 0;
-  compositor->stage_presented_id = 0;
-  compositor->stage = NULL;
-
-  clutter_threads_remove_repaint_func (compositor->pre_paint_func_id);
-  clutter_threads_remove_repaint_func (compositor->post_paint_func_id);
-
-  if (compositor->top_window_actor)
-    {
-      g_signal_handler_disconnect (compositor->top_window_actor,
-                                   compositor->top_window_actor_destroy_id);
-      compositor->top_window_actor = NULL;
-      compositor->top_window_actor_destroy_id = 0;
-    }
-
-  g_clear_pointer (&compositor->window_group, clutter_actor_destroy);
-  g_clear_pointer (&compositor->top_window_group, clutter_actor_destroy);
-  g_clear_pointer (&compositor->feedback_group, clutter_actor_destroy);
-  g_clear_pointer (&compositor->windows, g_list_free);
-
-  if (compositor->have_x11_sync_object)
-    meta_sync_ring_destroy ();
+  g_object_run_dispose (G_OBJECT (compositor));
+  g_object_unref (compositor);
 }
 
 static void
@@ -1309,12 +1286,20 @@ on_shadow_factory_changed (MetaShadowFactory *factory,
 MetaCompositor *
 meta_compositor_new (MetaDisplay *display)
 {
-  MetaBackend *backend = meta_get_backend ();
-  ClutterBackend *clutter_backend = meta_backend_get_clutter_backend (backend);
   MetaCompositor *compositor;
 
-  compositor = g_new0 (MetaCompositor, 1);
+  compositor = g_object_new (META_TYPE_COMPOSITOR, NULL);
   compositor->display = display;
+
+  return compositor;
+}
+
+static void
+meta_compositor_init (MetaCompositor *compositor)
+{
+  MetaBackend *backend = meta_get_backend ();
+  ClutterBackend *clutter_backend = meta_backend_get_clutter_backend (backend);
+
   compositor->context = clutter_backend->cogl_context;
 
   g_signal_connect (meta_shadow_factory_get_default (),
@@ -1332,7 +1317,59 @@ meta_compositor_new (MetaDisplay *display)
                                            meta_post_paint_func,
                                            compositor,
                                            NULL);
-  return compositor;
+}
+
+static void
+meta_compositor_dispose (GObject *object)
+{
+  MetaCompositor *compositor = META_COMPOSITOR (object);
+
+  if (compositor->stage)
+    {
+      g_signal_handler_disconnect (compositor->stage,
+                                   compositor->stage_after_paint_id);
+      g_signal_handler_disconnect (compositor->stage,
+                                   compositor->stage_presented_id);
+
+      compositor->stage_after_paint_id = 0;
+      compositor->stage_presented_id = 0;
+      compositor->stage = NULL;
+    }
+
+  g_clear_handle_id (&compositor->pre_paint_func_id,
+                     clutter_threads_remove_repaint_func);
+  g_clear_handle_id (&compositor->post_paint_func_id,
+                     clutter_threads_remove_repaint_func);
+
+  if (compositor->top_window_actor)
+    {
+      g_signal_handlers_disconnect_by_func (compositor->top_window_actor,
+                                            on_top_window_actor_destroyed,
+                                            compositor);
+      compositor->top_window_actor = NULL;
+      compositor->top_window_actor_destroy_id = 0;
+    }
+
+  g_clear_pointer (&compositor->window_group, clutter_actor_destroy);
+  g_clear_pointer (&compositor->top_window_group, clutter_actor_destroy);
+  g_clear_pointer (&compositor->feedback_group, clutter_actor_destroy);
+  g_clear_pointer (&compositor->windows, g_list_free);
+
+  if (compositor->have_x11_sync_object)
+    {
+      meta_sync_ring_destroy ();
+      compositor->have_x11_sync_object = FALSE;
+    }
+
+  G_OBJECT_CLASS (meta_compositor_parent_class)->dispose (object);
+}
+
+static void
+meta_compositor_class_init (MetaCompositorClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->dispose = meta_compositor_dispose;
 }
 
 /**

src/meta/compositor.h

@@ -28,6 +28,10 @@
 #include <meta/window.h>
 #include <meta/workspace.h>
 
+#define META_TYPE_COMPOSITOR (meta_compositor_get_type ())
+META_EXPORT
+G_DECLARE_FINAL_TYPE (MetaCompositor, meta_compositor, META, COMPOSITOR, GObject)
+
 /**
  * MetaCompEffect:
  * @META_COMP_EFFECT_CREATE: The window is newly created