[gtk/css-lookup-caching: 16/26] cssnode: Reused cached lookups

[Matthias Clasen <matthiasc src gnome org>]

commit c131520e7f239265a31a5d1435eb664e9edba203
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Feb 10 19:32:25 2020 -0500

    cssnode: Reused cached lookups
    
    When we determine that the lookup won't change,
    reuse the cached lookup by passing it to
    to gtk_css_static_style_new_compute.

 gtk/gtkcssnode.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkcssnode.c b/gtk/gtkcssnode.c
index 5e6d320380..899f527356 100644
--- a/gtk/gtkcssnode.c
+++ b/gtk/gtkcssnode.c
@@ -364,6 +364,7 @@ gtk_css_node_create_style (GtkCssNode                   *cssnode,
   const GtkCssNodeDeclaration *decl;
   GtkCssStyle *style;
   GtkCssChange style_change;
+  GtkCssLookup *lookup;
 
   style_change = gtk_css_static_style_get_change (GTK_CSS_STATIC_STYLE (static_style));
 
@@ -378,13 +379,19 @@ gtk_css_node_create_style (GtkCssNode                   *cssnode,
 
   created_styles++;
 
-  if (change & GTK_CSS_CHANGE_NEEDS_RECOMPUTE)
+  if ((change & GTK_CSS_CHANGE_SOURCE) == 0 &&
+      (change & style_change) == 0)
+    lookup = gtk_css_static_style_get_lookup (GTK_CSS_STATIC_STYLE (static_style));
+  else
+    lookup = NULL;
+
+  if ((change & GTK_CSS_CHANGE_NEEDS_RECOMPUTE) != 0)
     style_change = 0;
 
   style = gtk_css_static_style_new_compute (gtk_css_node_get_style_provider (cssnode),
                                             filter,
                                             cssnode,
-                                            NULL,
+                                            lookup,
                                             style_change);
 
   store_in_global_parent_cache (cssnode, decl, style);