GtkStyleContext: Add child style classes.

Child style classes are like style classes, but with additional positional
information. This would be usually set by the parent container.

gtk/gtkstylecontext.c

@@ -30,6 +30,13 @@
 
 typedef struct GtkStyleContextPrivate GtkStyleContextPrivate;
 typedef struct GtkStyleProviderData GtkStyleProviderData;
+typedef struct GtkChildClass GtkChildClass;
+
+struct GtkChildClass
+{
+  GQuark class_quark;
+  GtkChildClassFlags flags;
+};
 
 struct GtkStyleProviderData
 {
@@ -45,6 +52,7 @@ struct GtkStyleContextPrivate
 
   GtkStateFlags state_flags;
   GList *style_classes;
+  GList *child_style_classes;
 
   GtkThemingEngine *theming_engine;
 };
@@ -444,5 +452,136 @@ gtk_style_context_has_class (GtkStyleContext *context,
   return FALSE;
 }
 
+static gint
+child_style_class_compare (gconstpointer p1,
+                           gconstpointer p2)
+{
+  const GtkChildClass *c1, *c2;
+
+  c1 = p1;
+  c2 = p2;
+
+  return (gint) c1->class_quark - c2->class_quark;
+}
+
+void
+gtk_style_context_set_child_class (GtkStyleContext    *context,
+                                   const gchar        *class_name,
+                                   GtkChildClassFlags  flags)
+{
+  GtkStyleContextPrivate *priv;
+  GtkChildClass *child_class;
+  GQuark class_quark;
+  GList *link;
+
+  g_return_if_fail (GTK_IS_STYLE_CONTEXT (context));
+  g_return_if_fail (class_name != NULL);
+
+  priv = GTK_STYLE_CONTEXT_GET_PRIVATE (context);
+  class_quark = g_quark_from_string (class_name);
+  link = priv->style_classes;
+
+  while (link)
+    {
+      GtkChildClass *link_class;
+
+      link_class = link->data;
+
+      if (link_class->class_quark == class_quark)
+        {
+          link_class->flags = flags;
+          return;
+        }
+      else if (link_class->class_quark > class_quark)
+        break;
+
+      link = link->next;
+    }
+
+  child_class = g_slice_new0 (GtkChildClass);
+  child_class->class_quark = class_quark;
+  child_class->flags = flags;
+
+  if (link)
+    priv->style_classes = g_list_insert_before (priv->style_classes,
+                                                link, child_class);
+  else
+    priv->style_classes = g_list_append (priv->style_classes, child_class);
+}
+
+void
+gtk_style_context_unset_child_class (GtkStyleContext    *context,
+                                     const gchar        *class_name)
+{
+  GtkStyleContextPrivate *priv;
+  GtkChildClass child_class;
+  GQuark class_quark;
+  GList *link;
+
+  g_return_if_fail (GTK_IS_STYLE_CONTEXT (context));
+  g_return_if_fail (class_name != NULL);
+
+  class_quark = g_quark_try_string (class_name);
+
+  if (!class_quark)
+    return;
+
+  priv = GTK_STYLE_CONTEXT_GET_PRIVATE (context);
+  child_class.class_quark = class_quark;
+
+  link = g_list_find_custom (priv->child_style_classes,
+                             &child_class, child_style_class_compare);
+
+  if (link)
+    {
+      priv->child_style_classes = g_list_remove_link (priv->child_style_classes, link);
+      g_slice_free (GtkChildClass, link->data);
+      g_list_free1 (link);
+    }
+}
+
+gboolean
+gtk_style_context_has_child_class (GtkStyleContext    *context,
+                                   const gchar        *class_name,
+                                   GtkChildClassFlags *flags_return)
+{
+  GtkStyleContextPrivate *priv;
+  GtkChildClass child_class;
+  GQuark class_quark;
+  GList *link;
+
+  g_return_val_if_fail (GTK_IS_STYLE_CONTEXT (context), FALSE);
+  g_return_val_if_fail (class_name != NULL, FALSE);
+
+  if (flags_return)
+    *flags_return = 0;
+
+  class_quark = g_quark_try_string (class_name);
+
+  if (!class_quark)
+    return FALSE;
+
+  priv = GTK_STYLE_CONTEXT_GET_PRIVATE (context);
+  child_class.class_quark = class_quark;
+
+  link = g_list_find_custom (priv->child_style_classes,
+                             &child_class, child_style_class_compare);
+
+  if (link)
+    {
+      if (*flags_return)
+        {
+          GtkChildClass *found_class;
+
+          found_class = link->data;
+          *flags_return = found_class->flags;
+        }
+
+      return TRUE;
+    }
+
+  return FALSE;
+}
+
 #define __GTK_STYLE_CONTEXT_C__
 #include "gtkaliasdef.c"

gtk/gtkstylecontext.h

@@ -36,6 +36,15 @@ G_BEGIN_DECLS
 typedef struct GtkStyleContext GtkStyleContext;
 typedef struct GtkStyleContextClass GtkStyleContextClass;
 
+typedef enum {
+  GTK_CHILD_CLASS_EVEN    = 1 << 0,
+  GTK_CHILD_CLASS_ODD     = 1 << 1,
+  GTK_CHILD_CLASS_FIRST   = 1 << 2,
+  GTK_CHILD_CLASS_LAST    = 1 << 3,
+  GTK_CHILD_CLASS_DEFAULT = 1 << 4,
+  GTK_CHILD_CLASS_SORTED  = 1 << 5
+} GtkChildClassFlags;
+
 struct GtkStyleContext
 {
   GObject parent_object;
@@ -84,6 +93,14 @@ void     gtk_style_context_unset_class (GtkStyleContext *context,
 gboolean gtk_style_context_has_class   (GtkStyleContext *context,
                                         const gchar     *class_name);
 
+void     gtk_style_context_set_child_class   (GtkStyleContext    *context,
+                                              const gchar        *class_name,
+                                              GtkChildClassFlags  flags);
+void     gtk_style_context_unset_child_class (GtkStyleContext    *context,
+                                              const gchar        *class_name);
+gboolean gtk_style_context_has_child_class   (GtkStyleContext    *context,
+                                              const gchar        *class_name,
+                                              GtkChildClassFlags *flags_return);
 
 G_END_DECLS