API: Add gtk_widget_path_to_string()

Dumps the widget path into a string representation. It tries to match the CSS
style as closely as possible (Note that there might be paths that cannot be
represented in CSS).

The main use of this code is for debugging purposes, so that you can
g_print() the path or dump it in a gdb session.

docs/reference/gtk/gtk3-sections.txt

@@ -5438,6 +5438,7 @@ gtk_widget_path_iter_set_object_type
 gtk_widget_path_length
 gtk_widget_path_new
 gtk_widget_path_prepend_type
+gtk_widget_path_to_string
 
 <SUBSECTION Standard>
 GTK_TYPE_WIDGET_PATH

gtk/gtk.symbols

@@ -3588,6 +3588,7 @@ gtk_widget_path_iter_set_object_type
 gtk_widget_path_length
 gtk_widget_path_new
 gtk_widget_path_prepend_type
+gtk_widget_path_to_string
 gtk_widget_pop_composite_child
 gtk_widget_push_composite_child
 gtk_widget_queue_compute_expand

gtk/gtkwidgetpath.c

@@ -224,6 +224,90 @@ gtk_widget_path_length (const GtkWidgetPath *path)
   return path->elems->len;
 }
 
+/**
+ * gtk_widget_path_to_string:
+ * @path: the path
+ *
+ * Dumps the widget path into a string representation. It tries to match
+ * the CSS style as closely as possible (Note that there might be paths
+ * that cannot be represented in CSS).
+ *                 
+ * The main use of this code is for debugging purposes, so that you can
+ * g_print() the path or dump it in a gdb session.
+ *
+ * Returns: A new string describing @path.
+ **/
+char *
+gtk_widget_path_to_string (const GtkWidgetPath *path)
+{
+  GString *string;
+  guint i, j;
+
+  g_return_val_if_fail (path != NULL, NULL);
+
+  string = g_string_new ("");
+
+  for (i = 0; i < path->elems->len; i++)
+    {
+      GtkPathElement *elem;
+
+      elem = &g_array_index (path->elems, GtkPathElement, i);
+
+      if (i > 0)
+        g_string_append_c (string, ' ');
+
+      g_string_append (string, g_type_name (elem->type));
+
+      if (elem->name)
+        {
+          g_string_append_c (string, '(');
+          g_string_append (string, g_quark_to_string (elem->name));
+          g_string_append_c (string, ')');
+        }
+
+      if (elem->classes)
+        {
+          for (j = 0; j < elem->classes->len; j++)
+            {
+              g_string_append_c (string, '.');
+              g_string_append (string, g_quark_to_string (g_array_index (elem->classes, GQuark, j)));
+            }
+        }
+
+      if (elem->regions)
+        {
+          GHashTableIter iter;
+          gpointer key, value;
+
+          g_hash_table_iter_init (&iter, elem->regions);
+          while (g_hash_table_iter_next (&iter, &key, &value))
+            {
+              GtkRegionFlags flags = GPOINTER_TO_UINT (value);
+              static const char *flag_names[] = {
+                "even",
+                "odd",
+                "first",
+                "last",
+                "sorted"
+              };
+
+              g_string_append_c (string, ' ');
+              g_string_append (string, g_quark_to_string (GPOINTER_TO_UINT (key)));
+              for (j = 0; j < G_N_ELEMENTS(flag_names); j++)
+                {
+                  if (flags & (1 << j))
+                    {
+                      g_string_append_c (string, ':');
+                      g_string_append (string, flag_names[j]);
+                    }
+                }
+            }
+        }
+    }
+
+  return g_string_free (string, FALSE);
+}
+
 /**
  * gtk_widget_path_prepend_type:
  * @path: a #GtkWidgetPath

gtk/gtkwidgetpath.h

@@ -39,6 +39,7 @@ GtkWidgetPath * gtk_widget_path_new                 (void);
 GtkWidgetPath * gtk_widget_path_copy                (const GtkWidgetPath *path);
 void            gtk_widget_path_free                (GtkWidgetPath       *path);
 
+char *          gtk_widget_path_to_string           (const GtkWidgetPath *path);
 gint            gtk_widget_path_length              (const GtkWidgetPath *path);
 
 gint            gtk_widget_path_append_type         (GtkWidgetPath       *path,