From 4c1cf8d9c4269346f2b7b0a67d9ac4ed3c084eda Mon Sep 17 00:00:00 2001
From: Sven Oesau <sven.oesau@geometryfactory.com>
Date: Tue, 6 Feb 2024 10:18:35 +0100
Subject: [PATCH] working version of Pair_optional_adaptor

---
 Orthtree/include/CGAL/Orthtree.h              |  2 +-
 .../test_octree_custom_properties.cpp         |  8 ++++++
 .../include/CGAL/Pair_optional_adaptor.h      | 27 ++++++-------------
 3 files changed, 17 insertions(+), 20 deletions(-)

diff --git a/Orthtree/include/CGAL/Orthtree.h b/Orthtree/include/CGAL/Orthtree.h
index ca7bec5de3d..dc2e41555d1 100644
--- a/Orthtree/include/CGAL/Orthtree.h
+++ b/Orthtree/include/CGAL/Orthtree.h
@@ -511,7 +511,7 @@ public:
     \return pair of the property map and a Boolean which is `true` if the property needed to be created
    */
   template <typename T>
-  std::pair<Property_map<T>, bool>
+  Pair_optional_adaptor<Property_map<T>>
   add_property(const std::string& name, const T default_value = T()) {
     auto p = m_node_properties.get_or_add_property(name, default_value);
     return std::pair<Property_map<T>, bool>(Property_map<T>(p.first), p.second);
diff --git a/Orthtree/test/Orthtree/test_octree_custom_properties.cpp b/Orthtree/test/Orthtree/test_octree_custom_properties.cpp
index e75837a0312..0e14a51fbbc 100644
--- a/Orthtree/test/Orthtree/test_octree_custom_properties.cpp
+++ b/Orthtree/test/Orthtree/test_octree_custom_properties.cpp
@@ -39,6 +39,14 @@ int main(void) {
   auto prop5 = tree.add_property("test", int(0));
   assert(!prop5.second);
 
+  auto a3 = tree.add_property("test1", int(0));
+  std::pair<typename Octree::Property_map<int>, bool> p3 = tree.add_property("test2", int(0));
+  std::optional<typename Octree::Property_map<int>> o3 = tree.add_property("test3", int(0));
+
+  auto a4 = tree.add_property("test", int(0));
+  std::pair<typename Octree::Property_map<int>, bool> p4 = tree.add_property("test", int(0));
+  std::optional<typename Octree::Property_map<int>> o4 = tree.add_property("test", int(0));
+
   auto a1 = tree.property<int>("test");
   std::pair<typename Octree::Property_map<int>, bool> p1 = tree.property<int>("test");
   std::optional<typename Octree::Property_map<int>> o1 = tree.property<int>("test");
diff --git a/STL_Extension/include/CGAL/Pair_optional_adaptor.h b/STL_Extension/include/CGAL/Pair_optional_adaptor.h
index 1620edbf3b2..49c5c076dfd 100644
--- a/STL_Extension/include/CGAL/Pair_optional_adaptor.h
+++ b/STL_Extension/include/CGAL/Pair_optional_adaptor.h
@@ -19,40 +19,29 @@ namespace CGAL {
 template<typename T>
 class Pair_optional_adaptor : public std::optional<T> {
 public:
-  Pair_optional_adaptor(std::optional<T>& obj) : std::optional<T>(obj), second(obj.has_value()), first(u.t) {
-    std::cout << "optional constructor" << std::endl;
+  Pair_optional_adaptor(std::optional<T>& obj) : std::optional<T>(obj), second(obj.has_value()), first(t_storage.t) {
     if (obj.has_value())
-      u.t = *obj;
+      t_storage.t = *obj;
   }
 
-  Pair_optional_adaptor(const std::nullopt_t& obj) : std::optional<T>(std::nullopt), second(false), first(u.t) {
-    std::cout << "nullopt constructor" << std::endl;
-  }
+  Pair_optional_adaptor(const std::nullopt_t& obj) : std::optional<T>(std::nullopt), second(false), first(t_storage.t) {}
 
-  Pair_optional_adaptor(std::pair<T, bool>& p) : std::optional<T>(b ? p.first : std::nullopt), first(p.first), second(b) {
-    std::cout << "pair constructor" << std::endl;
-  }
+  Pair_optional_adaptor(std::pair<T, bool>& p) : std::optional<T>(p.second ? p.first : std::optional<T>()), first(t_storage.t), second(p.second), t_storage(p.first) {}
 
   operator std::pair<T, bool>() {
     return std::pair<T, bool>(first, second);
   }
 
-  operator std::optional<T>() {
-    if (second)
-      return std::optional<T>(first);
-    else return std::nullopt;
-  }
-
   T &first;
   bool second;
 
 private:
-  union U {
+  union T_value {
     T t;
     int i;
-    U() : i(0) {}
-    U(T t) : t(t) {}
-  } u;
+    T_value() : i(0) {}
+    T_value(T t) : t(t) {}
+  } t_storage;
 };
 
 } // CGAL