From 2fb61e7c71b7fcd7b60c64de44bbb4e6dca79b7d Mon Sep 17 00:00:00 2001
From: Sebastian Messmer <messmer@cryfs.org>
Date: Mon, 3 Apr 2017 15:43:27 +0100
Subject: [PATCH] Further improve unique_ref

---
 src/cpp-utils/pointer/unique_ref.h         | 12 +++++-----
 test/cpp-utils/pointer/unique_ref_test.cpp | 26 ++++++++++++++++++++++
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/src/cpp-utils/pointer/unique_ref.h b/src/cpp-utils/pointer/unique_ref.h
index 55b6b6e7..0ec70955 100644
--- a/src/cpp-utils/pointer/unique_ref.h
+++ b/src/cpp-utils/pointer/unique_ref.h
@@ -45,7 +45,7 @@ public:
         from._target = nullptr;
         return *this;
     }
-    
+
     template<class U> unique_ref& operator=(unique_ref<U>&& from) noexcept {
         _target = std::move(from._target);
         from._target = nullptr;
@@ -70,12 +70,14 @@ public:
         return _target.get();
     }
 
-    operator std::unique_ptr<element_type>() && noexcept {
-        return std::move(_target);
+    template<class T2>
+    operator std::unique_ptr<T2>() && noexcept {
+      return std::move(_target);
     }
 
-    operator std::shared_ptr<element_type>() && noexcept {
-        return std::move(_target);
+    template<class T2>
+    operator std::shared_ptr<T2>() && noexcept {
+      return std::move(_target);
     }
 
     void swap(unique_ref& rhs) noexcept {
diff --git a/test/cpp-utils/pointer/unique_ref_test.cpp b/test/cpp-utils/pointer/unique_ref_test.cpp
index cbdb9109..d04bcc4e 100644
--- a/test/cpp-utils/pointer/unique_ref_test.cpp
+++ b/test/cpp-utils/pointer/unique_ref_test.cpp
@@ -79,6 +79,16 @@ TEST(MakeUniqueRefTest, CanAssignToSharedPtr) {
   EXPECT_EQ(3, var->v);
 }
 
+TEST(MakeUniqueRefTest, CanAssignToBaseClassUniquePtr) {
+  std::unique_ptr<SomeBaseClass> var = make_unique_ref<SomeChildClass>(3);
+  EXPECT_EQ(3, var->v);
+}
+
+TEST(MakeUniqueRefTest, CanAssignToBaseClassSharedPtr) {
+  std::shared_ptr<SomeBaseClass> var = make_unique_ref<SomeChildClass>(3);
+  EXPECT_EQ(3, var->v);
+}
+
 TEST(NullcheckTest, PrimitiveNullptr) {
   boost::optional<unique_ref<int>> var = nullcheck(std::unique_ptr<int>(nullptr));
   EXPECT_FALSE((bool)var);
@@ -579,3 +589,19 @@ TEST_F(UniqueRefTest, givenUniqueRefToChildClass_whenMoveAssignedToBaseClass_the
   base = std::move(child);
   EXPECT_EQ(3, base->v);
 }
+
+TEST_F(UniqueRefTest, givenUniqueRefToChildClass_whenCastedToBaseClassUniquePtr_thenWorksAsExpected) {
+  unique_ref<SomeChildClass> child = make_unique_ref<SomeChildClass>(3);
+  std::unique_ptr<SomeBaseClass> base = std::make_unique<SomeBaseClass>(10);
+  base = std::move(child);
+  EXPECT_FALSE(child.isValid());
+  EXPECT_EQ(3, base->v);
+}
+
+TEST_F(UniqueRefTest, givenUniqueRefToChildClass_whenCastedToBaseClassSharedPtr_thenWorksAsExpected) {
+  unique_ref<SomeChildClass> child = make_unique_ref<SomeChildClass>(3);
+  std::shared_ptr<SomeBaseClass> base = std::make_unique<SomeBaseClass>(10);
+  base = std::move(child);
+  EXPECT_FALSE(child.isValid());
+  EXPECT_EQ(3, base->v);
+}