1 files changed, 73 insertions, 0 deletions
diff --git a/source/blender/depsgraph/intern/depsgraph_relation.cc b/source/blender/depsgraph/intern/depsgraph_relation.cc
new file mode 100644
index 00000000000..387582ca4e0
--- /dev/null
+++ b/source/blender/depsgraph/intern/depsgraph_relation.cc
@@ -0,0 +1,73 @@
+/*
+ * 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 2
+ * 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, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2020 Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup depsgraph
+ */
+
+#include "intern/depsgraph_relation.h" /* own include */
+
+#include "BLI_utildefines.h"
+
+#include "intern/depsgraph_type.h"
+#include "intern/node/deg_node.h"
+
+namespace DEG {
+
+/* TODO(sergey): Find a better place for this. */
+template<typename T> static void remove_from_vector(vector<T> *vector, const T &value)
+{
+  vector->erase(std::remove(vector->begin(), vector->end(), value), vector->end());
+}
+
+Relation::Relation(Node *from, Node *to, const char *description)
+    : from(from), to(to), name(description), flag(0)
+{
+  /* Hook it up to the nodes which use it.
+   *
+   * NOTE: We register relation in the nodes which this link connects to here
+   * in constructor but we don't unregister it in the destructor.
+   *
+   * Reasoning:
+   *
+   * - Destructor is currently used on global graph destruction, so there's no
+   *   real need in avoiding dangling pointers, all the memory is to be freed
+   *   anyway.
+   *
+   * - Unregistering relation is not a cheap operation, so better to have it
+   *   as an explicit call if we need this. */
+  from->outlinks.push_back(this);
+  to->inlinks.push_back(this);
+}
+
+Relation::~Relation()
+{
+  /* Sanity check. */
+  BLI_assert(from != NULL && to != NULL);
+}
+
+void Relation::unlink()
+{
+  /* Sanity check. */
+  BLI_assert(from != NULL && to != NULL);
+  remove_from_vector(&from->outlinks, this);
+  remove_from_vector(&to->inlinks, this);
+}
+
+}  // namespace DEG