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 02eb95e52dc8c52e612eadef5d18f53684f71fd2..b8028925e4f9f7bcb5de52bb19846f8577d361fb 100644 (file)
--- a/src/st/st-theme-node-private.h
+++ b/src/st/st-theme-node-private.h
@@ -105,7 +105,7 @@ 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 51e6d21740657fa039151fffcda9f3147b067d4c..31b27583c700a818e5f156db131e763f3c8a88f5 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);
@@ -473,6 +476,16 @@ 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);
+        }
     }
 }