[Wayland] Avoid using buffers with unfinished client work

src/compositor/meta-window-actor-wayland.c

@@ -108,7 +108,7 @@ meta_window_actor_wayland_rebuild_surface_tree (MetaWindowActor *actor)
     meta_window_actor_get_surface (actor);
   MetaWaylandSurface *surface = meta_surface_actor_wayland_get_surface (
     META_SURFACE_ACTOR_WAYLAND (surface_actor));
-  GNode *root_node = surface->subsurface_branch_node;
+  GNode *root_node = surface->output_state.subsurface_branch_node;
   g_autoptr (GList) surface_actors = NULL;
   g_autoptr (GList) children = NULL;
   GList *l;

src/meson.build

@@ -601,6 +601,8 @@ if have_wayland
     'wayland/meta-wayland-virtual-keyboard.h',
     'wayland/meta-wayland-touch.c',
     'wayland/meta-wayland-touch.h',
+    'wayland/meta-wayland-transaction.c',
+    'wayland/meta-wayland-transaction.h',
     'wayland/meta-wayland-types.h',
     'wayland/meta-wayland-versions.h',
     'wayland/meta-wayland-viewporter.c',

src/wayland/meta-wayland-actor-surface.c

@@ -181,16 +181,18 @@ meta_wayland_actor_surface_real_sync_actor_state (MetaWaylandActorSurface *actor
   surface_actor = priv->actor;
   stex = meta_surface_actor_get_texture (surface_actor);
 
-  buffer = surface->buffer_ref->buffer;
+  buffer = meta_wayland_surface_get_buffer (surface);
   if (buffer)
     {
       CoglSnippet *snippet;
       gboolean is_y_inverted;
+      CoglTexture *texture;
 
       snippet = meta_wayland_buffer_create_snippet (buffer);
       is_y_inverted = meta_wayland_buffer_is_y_inverted (buffer);
 
-      meta_shaped_texture_set_texture (stex, surface->texture);
+      texture = meta_wayland_surface_get_texture (surface);
+      meta_shaped_texture_set_texture (stex, texture);
       meta_shaped_texture_set_snippet (stex, snippet);
       meta_shaped_texture_set_is_y_inverted (stex, is_y_inverted);
       meta_shaped_texture_set_buffer_scale (stex, surface->scale);
@@ -270,7 +272,8 @@ meta_wayland_actor_surface_real_sync_actor_state (MetaWaylandActorSurface *actor
 
   meta_shaped_texture_ensure_size_valid (stex);
 
-  META_WAYLAND_SURFACE_FOREACH_SUBSURFACE (surface, subsurface_surface)
+  META_WAYLAND_SURFACE_FOREACH_SUBSURFACE (&surface->output_state,
+                                           subsurface_surface)
     {
       MetaWaylandActorSurface *actor_surface;
 
@@ -457,7 +460,8 @@ meta_wayland_actor_surface_reset_actor (MetaWaylandActorSurface *actor_surface)
     meta_wayland_surface_role_get_surface (META_WAYLAND_SURFACE_ROLE (actor_surface));
   MetaWaylandSurface *subsurface_surface;
 
-  META_WAYLAND_SURFACE_FOREACH_SUBSURFACE (surface, subsurface_surface)
+  META_WAYLAND_SURFACE_FOREACH_SUBSURFACE (&surface->output_state,
+                                           subsurface_surface)
     {
       MetaWaylandActorSurface *actor_surface;
 

src/wayland/meta-wayland-buffer.c

@@ -173,7 +173,8 @@ meta_wayland_buffer_realize (MetaWaylandBuffer *buffer)
                                      EGL_TEXTURE_FORMAT, &format,
                                      NULL))
     {
-      buffer->type = META_WAYLAND_BUFFER_TYPE_EGL_IMAGE;
+      buffer->dma_buf.dma_buf =
+        meta_wayland_dma_buf_fds_for_wayland_buffer (buffer);
       return TRUE;
     }
 
@@ -506,7 +507,6 @@ meta_wayland_buffer_attach (MetaWaylandBuffer  *buffer,
                             CoglTexture       **texture,
                             GError            **error)
 {
-  g_return_val_if_fail (buffer->resource, FALSE);
 
   if (!meta_wayland_buffer_is_realized (buffer))
     {
@@ -566,6 +566,25 @@ meta_wayland_buffer_create_snippet (MetaWaylandBuffer *buffer)
 #endif /* HAVE_WAYLAND_EGLSTREAM */
 }
 
+void
+meta_wayland_buffer_inc_use_count (MetaWaylandBuffer *buffer)
+{
+  g_warn_if_fail (buffer->resource);
+
+  buffer->use_count++;
+}
+
+void
+meta_wayland_buffer_dec_use_count (MetaWaylandBuffer *buffer)
+{
+  g_return_if_fail (buffer->use_count > 0);
+
+  buffer->use_count--;
+
+  if (buffer->use_count == 0 && buffer->resource)
+    wl_buffer_send_release (buffer->resource);
+}
+
 gboolean
 meta_wayland_buffer_is_y_inverted (MetaWaylandBuffer *buffer)
 {
@@ -754,6 +773,8 @@ meta_wayland_buffer_finalize (GObject *object)
 {
   MetaWaylandBuffer *buffer = META_WAYLAND_BUFFER (object);
 
+  g_warn_if_fail (buffer->use_count == 0);
+
   g_clear_pointer (&buffer->egl_image.texture, cogl_object_unref);
 #ifdef HAVE_WAYLAND_EGLSTREAM
   g_clear_pointer (&buffer->egl_stream.texture, cogl_object_unref);

src/wayland/meta-wayland-buffer.h

@@ -53,6 +53,8 @@ struct _MetaWaylandBuffer
   struct wl_resource *resource;
   struct wl_listener destroy_listener;
 
+  unsigned int use_count;
+
   gboolean is_y_inverted;
 
   MetaWaylandBufferType type;
@@ -91,6 +93,8 @@ gboolean                meta_wayland_buffer_attach              (MetaWaylandBuff
                                                                  CoglTexture          **texture,
                                                                  GError               **error);
 CoglSnippet *           meta_wayland_buffer_create_snippet      (MetaWaylandBuffer     *buffer);
+void                    meta_wayland_buffer_inc_use_count       (MetaWaylandBuffer     *buffer);
+void                    meta_wayland_buffer_dec_use_count       (MetaWaylandBuffer     *buffer);
 gboolean                meta_wayland_buffer_is_y_inverted       (MetaWaylandBuffer     *buffer);
 void                    meta_wayland_buffer_process_damage      (MetaWaylandBuffer     *buffer,
                                                                  CoglTexture           *texture,

src/wayland/meta-wayland-cursor-surface.c

@@ -139,12 +139,10 @@ meta_wayland_cursor_surface_pre_apply_state (MetaWaylandSurfaceRole  *surface_ro
     META_WAYLAND_CURSOR_SURFACE (surface_role);
   MetaWaylandCursorSurfacePrivate *priv =
     meta_wayland_cursor_surface_get_instance_private (cursor_surface);
-  MetaWaylandSurface *surface =
-    meta_wayland_surface_role_get_surface (surface_role);
 
   if (pending->newly_attached && priv->buffer)
     {
-      meta_wayland_surface_unref_buffer_use_count (surface);
+      meta_wayland_buffer_dec_use_count (priv->buffer);
       g_clear_object (&priv->buffer);
     }
 }
@@ -157,15 +155,11 @@ meta_wayland_cursor_surface_apply_state (MetaWaylandSurfaceRole  *surface_role,
     META_WAYLAND_CURSOR_SURFACE (surface_role);
   MetaWaylandCursorSurfacePrivate *priv =
     meta_wayland_cursor_surface_get_instance_private (cursor_surface);
-  MetaWaylandSurface *surface =
-    meta_wayland_surface_role_get_surface (surface_role);
-  MetaWaylandBuffer *buffer = meta_wayland_surface_get_buffer (surface);
 
-  if (pending->newly_attached)
+  if (pending->buffer)
     {
-      g_set_object (&priv->buffer, buffer);
-      if (priv->buffer)
-        meta_wayland_surface_ref_buffer_use_count (surface);
+      priv->buffer = g_object_ref (pending->buffer);
+      meta_wayland_buffer_inc_use_count (priv->buffer);
     }
 
   wl_list_insert_list (&priv->frame_callbacks,
@@ -210,8 +204,6 @@ meta_wayland_cursor_surface_dispose (GObject *object)
     META_WAYLAND_CURSOR_SURFACE (object);
   MetaWaylandCursorSurfacePrivate *priv =
     meta_wayland_cursor_surface_get_instance_private (cursor_surface);
-  MetaWaylandSurface *surface =
-    meta_wayland_surface_role_get_surface (META_WAYLAND_SURFACE_ROLE (object));
   MetaWaylandFrameCallback *cb, *next;
 
   wl_list_for_each_safe (cb, next, &priv->frame_callbacks, link)
@@ -225,7 +217,7 @@ meta_wayland_cursor_surface_dispose (GObject *object)
 
   if (priv->buffer)
     {
-      meta_wayland_surface_unref_buffer_use_count (surface);
+      meta_wayland_buffer_dec_use_count (priv->buffer);
       g_clear_object (&priv->buffer);
     }
 
@@ -251,8 +243,8 @@ meta_wayland_cursor_surface_constructed (GObject *object)
 
   if (buffer && buffer->resource)
     {
-      g_set_object (&priv->buffer, buffer);
-      meta_wayland_surface_ref_buffer_use_count (surface);
+      priv->buffer = g_object_ref (surface->buffer);
+      meta_wayland_buffer_inc_use_count (priv->buffer);
     }
 
   priv->cursor_sprite = meta_cursor_sprite_wayland_new (surface);