1 files changed, 95 insertions, 0 deletions
diff --git a/app/core/gimp-atomic.c b/app/core/gimp-atomic.c
new file mode 100644
index 0000000..c5a54b8
--- /dev/null
+++ b/app/core/gimp-atomic.c
@@ -0,0 +1,95 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * gimp-atomic.c
+ * Copyright (C) 2018 Ell
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <gdk-pixbuf/gdk-pixbuf.h>
+#include <gegl.h>
+
+#include "core-types.h"
+
+#include "gimp-atomic.h"
+
+
+/*  GSList  */
+
+
+static GSList gimp_atomic_slist_sentinel;
+
+
+void
+gimp_atomic_slist_push_head (GSList   * volatile *list,
+                             gpointer             data)
+{
+  GSList *old_head;
+  GSList *new_head;
+
+  g_return_if_fail (list != NULL);
+
+  new_head = g_slist_alloc ();
+
+  new_head->data = data;
+
+  do
+    {
+      do
+        {
+          old_head = g_atomic_pointer_get (list);
+        }
+      while (old_head == &gimp_atomic_slist_sentinel);
+
+      new_head->next = old_head;
+    }
+  while (! g_atomic_pointer_compare_and_exchange (list, old_head, new_head));
+}
+
+gpointer
+gimp_atomic_slist_pop_head (GSList * volatile *list)
+{
+  GSList   *old_head;
+  GSList   *new_head;
+  gpointer  data;
+
+  g_return_val_if_fail (list != NULL, NULL);
+
+  do
+    {
+      do
+        {
+          old_head = g_atomic_pointer_get (list);
+        }
+      while (old_head == &gimp_atomic_slist_sentinel);
+
+      if (! old_head)
+        return NULL;
+    }
+  while (! g_atomic_pointer_compare_and_exchange (list,
+                                                  old_head,
+                                                  &gimp_atomic_slist_sentinel));
+
+  new_head = old_head->next;
+  data     = old_head->data;
+
+  g_atomic_pointer_set (list, new_head);
+
+  g_slist_free1 (old_head);
+
+  return data;
+}