From 7f19d641647ac4ef313ed88d6b5c140983ce5436 Mon Sep 17 00:00:00 2001
From: Vincent Ambo <mail@tazj.in>
Date: Wed, 15 Jul 2020 08:20:18 +0100
Subject: Squashed 'third_party/immer/' content from commit ad3e3556d

git-subtree-dir: third_party/immer
git-subtree-split: ad3e3556d38bb75966dd24c61a774970a7c7957e
---
 immer/transience/no_transience_policy.hpp | 48 +++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 immer/transience/no_transience_policy.hpp

(limited to 'immer/transience/no_transience_policy.hpp')

diff --git a/immer/transience/no_transience_policy.hpp b/immer/transience/no_transience_policy.hpp
new file mode 100644
index 000000000000..2f87df7a39b0
--- /dev/null
+++ b/immer/transience/no_transience_policy.hpp
@@ -0,0 +1,48 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+namespace immer {
+
+/*!
+ * Disables any special *transience* tracking.  To be used when
+ * *reference counting* is available instead.
+ */
+struct no_transience_policy
+{
+    template <typename>
+    struct apply
+    {
+        struct type
+        {
+            struct edit
+            {};
+
+            struct owner
+            {
+                operator edit() const { return {}; }
+            };
+
+            struct ownee
+            {
+                ownee& operator=(edit) { return *this; };
+                bool can_mutate(edit) const { return false; }
+                bool owned() const { return false; }
+            };
+
+            static owner noone;
+        };
+    };
+};
+
+template <typename HP>
+typename no_transience_policy::apply<HP>::type::owner
+    no_transience_policy::apply<HP>::type::noone = {};
+
+} // namespace immer
-- 
cgit 1.4.1