st/theme-node: Forget properties cache on stylesheet change

To avoid `node->properties` pointing to freed memory after each
`st_theme_unload_stylesheet`, flush the cache that is `node->properties`.
They will be reloaded as soon as they are required by `ensure_properties`.

And yes `node->stylesheets_changed_id` already existed, but was unused.

Why not just fix Croco? Croco does not use proper reference counting
everywhere it should, and retrofitting it would be difficult due to the
recursive nature of `CRDeclaration`.

Includes commit:
st/theme-node: Forget properties cache before unref'ing the theme
Which the properties point into.

Origin: https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3252
Bug: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/7339
Bug-Ubuntu: https://bugs.launchpad.net/bugs/2069559
Bug-Dash-to-Dock: https://github.com/micheleg/dash-to-dock/issues/2179

Gbp-Pq: Name st-theme-node-Forget-properties-cache-on-stylesheet-chang.patch

diff --git a/src/st/st-theme-node-private.h b/src/st/st-theme-node-private.h
index d95284e201af93ea76902d45cee12b755d761fbf..2d5065f05f7b8ad7816fdce143d2e443e624172a 100644 (file)
--- a/src/st/st-theme-node-private.h
+++ b/src/st/st-theme-node-private.h
@@ -104,7 +104,7 @@ struct _StThemeNode {
   int box_shadow_min_width;
   int box_shadow_min_height;
 
-  guint stylesheets_changed_id;
+  gulong stylesheets_changed_id;
 
   CoglTexture *border_slices_texture;
   CoglPipeline *border_slices_pipeline;

diff --git a/src/st/st-theme-node.c b/src/st/st-theme-node.c
index 0817e51fc78ed16ab266ac78017da316123298d4..1eb692529fde1e8061f2c899a275a7728eefbf1b 100644 (file)
--- a/src/st/st-theme-node.c
+++ b/src/st/st-theme-node.c
@@ -75,6 +75,10 @@ maybe_free_properties (StThemeNode *node)
       cr_declaration_destroy (node->inline_properties);
       node->inline_properties = NULL;
     }
+
+  g_clear_signal_handler (&node->stylesheets_changed_id, node->theme);
+
+  node->properties_computed = FALSE;
 }
 
 static void
@@ -102,6 +106,7 @@ st_theme_node_dispose (GObject *gobject)
 
   st_theme_node_paint_state_free (&node->cached_state);
 
+  maybe_free_properties (node);
   g_clear_object (&node->theme);
 
   G_OBJECT_CLASS (st_theme_node_parent_class)->dispose (gobject);
@@ -117,8 +122,6 @@ st_theme_node_finalize (GObject *object)
   g_strfreev (node->pseudo_classes);
   g_free (node->inline_style);
 
-  maybe_free_properties (node);
-
   g_clear_pointer (&node->font_desc, pango_font_description_free);
 
   g_clear_pointer (&node->box_shadow, st_shadow_unref);
@@ -472,6 +475,16 @@ ensure_properties (StThemeNode *node)
           node->n_properties = properties->len;
           node->properties = (CRDeclaration **)g_ptr_array_free (properties, FALSE);
         }
+
+      if (!node->stylesheets_changed_id)
+        {
+          node->stylesheets_changed_id =
+            g_signal_connect_object (node->theme,
+                                     "custom-stylesheets-changed",
+                                     G_CALLBACK (maybe_free_properties),
+                                     G_OBJECT (node),
+                                     G_CONNECT_SWAPPED);
+        }
     }
 }