cssnode: Redo GTK_DEBUG=no-css-cache

Previously this setting would just invalidate the whole CSS tree and
thereby hopefully avoid all cache usage.

Now, we actually don't cause extra invalidations anymore, but instead
avoid ever inserting anything into the cache when this setting is set.

1 files changed, 13 insertions, 0 deletions

diff --git a/gtk/gtkcssnodestylecache.c b/gtk/gtkcssnodestylecache.c
index 8c250bcac6..b07776d666 100644
--- a/gtk/gtkcssnodestylecache.c
+++ b/gtk/gtkcssnodestylecache.c
@@ -19,6 +19,7 @@
 
 #include "gtkcssnodestylecacheprivate.h"
 
+#include "gtkdebug.h"
 #include "gtkcssstaticstyleprivate.h"
 
 struct _GtkCssNodeStyleCache {
@@ -78,6 +79,18 @@ may_be_stored_in_cache (GtkCssStyle *style)
 {
   GtkCssChange change;
 
+  /* If you run your application with
+   *   GTK_DEBUG=no-css-cache
+   * no caching will happen. This is slow (in particular
+   * when animating), but useful for figuring out bugs.
+   *
+   * We achieve that by disallowing any inserts into caches here.
+   */
+#ifdef G_ENABLE_DEBUG
+  if (GTK_DEBUG_CHECK (NO_CSS_CACHE))
+    return FALSE;
+#endif
+
   if (!GTK_IS_CSS_STATIC_STYLE (style))
     return FALSE;