[gtk/wip/baedert/for-master: 18/19] cssimagefallback: Avoid allocating GPtrArray for colors

[Timm Bäder <baedert src gnome org>]

commit 484dcc043bc58e8c2fc650c76faec6490b5097fb
Author: Timm Bäder <mail baedert org>
Date:   Wed Sep 23 06:06:42 2020 +0200

    cssimagefallback: Avoid allocating GPtrArray for colors
    
    If we just parse a color, like image(#FFF), avoid allocating the
    GPtrArray to store images. This happens in Adwaita for background images
    of backdrop buttons. We save around 70 GPtrArrays this way.

 gtk/gtkcssimagefallback.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)
---
diff --git a/gtk/gtkcssimagefallback.c b/gtk/gtkcssimagefallback.c
index c6549c6bd4..4d320a395d 100644
--- a/gtk/gtkcssimagefallback.c
+++ b/gtk/gtkcssimagefallback.c
@@ -209,6 +209,9 @@ gtk_css_image_fallback_parse_arg (GtkCssParser *parser,
       if (image == NULL)
         return 0;
 
+      if (!data->images)
+        data->images = g_ptr_array_new_with_free_func (g_object_unref);
+
       g_ptr_array_add (data->images, image);
       return 1;
     }
@@ -235,18 +238,25 @@ gtk_css_image_fallback_parse (GtkCssImage  *image,
       return FALSE;
     }
 
-  data.images = g_ptr_array_new_with_free_func (g_object_unref);
-
   if (!gtk_css_parser_consume_function (parser, 1, G_MAXUINT, gtk_css_image_fallback_parse_arg, &data))
     {
       g_clear_pointer (&data.color, _gtk_css_value_unref);
-      g_ptr_array_free (data.images, TRUE);
+      if (data.images)
+        g_ptr_array_free (data.images, TRUE);
       return FALSE;
     }
 
   self->color = data.color;
-  self->n_images = data.images->len;
-  self->images = (GtkCssImage **) g_ptr_array_free (data.images, FALSE);
+  if (data.images)
+    {
+      self->n_images = data.images->len;
+      self->images = (GtkCssImage **) g_ptr_array_free (data.images, FALSE);
+    }
+  else
+    {
+      self->n_images = 0;
+      self->images = NULL;
+    }
 
   return TRUE;
 }