From 637bbbfd7ace2ee4d1f55420d3ecda32ea4d9ef3 Mon Sep 17 00:00:00 2001
From: Fred Suter <suterf@ornl.gov>
Date: Thu, 15 Jun 2023 11:17:47 -0400
Subject: [PATCH] add a get_unique_data to Extendable and test it in one
 example

---
 examples/cpp/io-disk-raw/s4u-io-disk-raw.cpp | 5 ++---
 include/xbt/Extendable.hpp                   | 3 +++
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/examples/cpp/io-disk-raw/s4u-io-disk-raw.cpp b/examples/cpp/io-disk-raw/s4u-io-disk-raw.cpp
index 8f2fc22adc..3c50a7bc79 100644
--- a/examples/cpp/io-disk-raw/s4u-io-disk-raw.cpp
+++ b/examples/cpp/io-disk-raw/s4u-io-disk-raw.cpp
@@ -43,14 +43,13 @@ static void host()
   /* - Attach some user data to disk1 */
   XBT_INFO("*** Get/set data for storage element: Disk1 ***");
 
-  const auto* data = disk->get_data<std::string>();
+  auto data = disk->get_unique_data<std::string>();
 
   XBT_INFO("Get storage data: '%s'", data ? data->c_str() : "No user data");
 
   disk->set_data(new std::string("Some user data"));
-  data = disk->get_data<std::string>();
+  data = disk->get_unique_data<std::string>();
   XBT_INFO("Set and get data: '%s'", data->c_str());
-  delete data;
 }
 
 int main(int argc, char** argv)
diff --git a/include/xbt/Extendable.hpp b/include/xbt/Extendable.hpp
index e315219f5c..8dbc3ab3d9 100644
--- a/include/xbt/Extendable.hpp
+++ b/include/xbt/Extendable.hpp
@@ -11,6 +11,7 @@
 #include <cstddef>
 #include <functional>
 #include <limits>
+#include <memory>
 #include <vector>
 
 namespace simgrid::xbt {
@@ -109,6 +110,8 @@ public:
     extensions_[0]=data;
   }
   template <typename D> D* get_data() const { return static_cast<D*>(extensions_[0]); }
+  template <typename D> std::unique_ptr<D> get_unique_data() { return std::unique_ptr<D>(get_data<D>()); }
+
   XBT_ATTRIB_DEPRECATED_v334("Please use typed template Extendable::get_data<>()") void* get_data() const
   {
     return get_data<void>();
-- 
2.20.1