[gtk+] cssshadowsvalue: Avoid allocating new value if not needed

[Benjamin Otte <otte src gnome org>]

commit c081ca2d4c589fb77e097ad5ee2a9978bd91d2ed
Author: Benjamin Otte <otte redhat com>
Date:   Thu Apr 21 22:28:58 2016 +0200

    cssshadowsvalue: Avoid allocating new value if not needed

 gtk/gtkcssshadowsvalue.c |   31 ++++++++++++++++++++++++++-----
 gtk/gtkcssshadowvalue.c  |   15 +++++++++++++++
 2 files changed, 41 insertions(+), 5 deletions(-)
---
diff --git a/gtk/gtkcssshadowsvalue.c b/gtk/gtkcssshadowsvalue.c
index 083b536..b58dde3 100644
--- a/gtk/gtkcssshadowsvalue.c
+++ b/gtk/gtkcssshadowsvalue.c
@@ -57,19 +57,40 @@ gtk_css_value_shadows_compute (GtkCssValue             *value,
                                GtkCssStyle             *style,
                                GtkCssStyle             *parent_style)
 {
-  GtkCssValue *result;
-  guint i;
+  GtkCssValue *result, *tmp;
+  guint i, j;
 
   if (value->len == 0)
     return _gtk_css_value_ref (value);
 
-  result = gtk_css_shadows_value_new (value->values, value->len);
+  result = NULL;
   for (i = 0; i < value->len; i++)
     {
-      result->values[i] = _gtk_css_value_compute (value->values[i], property_id, provider, style, 
parent_style);
+      tmp = _gtk_css_value_compute (value->values[i], property_id, provider, style, parent_style);
+
+      if (result)
+        {
+          result->values[i] = tmp;
+        }
+      else if (tmp != value->values[i])
+        {
+          result = gtk_css_shadows_value_new (value->values, value->len);
+          for (j = 0; j < i; j++)
+            {
+              _gtk_css_value_ref (result->values[j]);
+            }
+          result->values[i] = tmp;
+        }
+      else
+        {
+          _gtk_css_value_unref (tmp);
+        }
     }
 
-  return result;
+  if (result != NULL)
+    return result;
+  else
+    return _gtk_css_value_ref (value);
 }
 
 static gboolean
diff --git a/gtk/gtkcssshadowvalue.c b/gtk/gtkcssshadowvalue.c
index c06de2d..93b4dcf 100644
--- a/gtk/gtkcssshadowvalue.c
+++ b/gtk/gtkcssshadowvalue.c
@@ -77,6 +77,21 @@ gtk_css_value_shadow_compute (GtkCssValue             *shadow,
   spread = _gtk_css_value_compute (shadow->spread, property_id, provider, style, parent_style),
   color = _gtk_css_value_compute (shadow->color, property_id, provider, style, parent_style);
 
+  if (hoffset == shadow->hoffset &&
+      voffset == shadow->voffset &&
+      radius == shadow->radius &&
+      spread == shadow->spread &&
+      color == shadow->color)
+    {
+      _gtk_css_value_unref (hoffset);
+      _gtk_css_value_unref (voffset);
+      _gtk_css_value_unref (radius);
+      _gtk_css_value_unref (spread);
+      _gtk_css_value_unref (color);
+
+      return _gtk_css_value_ref (shadow);
+    }
+
   return gtk_css_shadow_value_new (hoffset, voffset, radius, spread, shadow->inset, color);
 }