GetRef in TPointerCommon

commit_hash:4149625a81c51af40642fe498a887608cc57305f

3 files changed, 50 insertions, 0 deletions

diff --git a/util/generic/ptr.cpp b/util/generic/ptr.cpp
index b29baebc175..963dcd5160c 100644
--- a/util/generic/ptr.cpp
+++ b/util/generic/ptr.cpp
@@ -1,4 +1,5 @@
 #include "ptr.h"
+#include "yexception.h"
 
 #include <util/system/defaults.h>
 #include <util/memory/alloc.h>
@@ -15,3 +16,7 @@ void TDelete::Destroy(void* t) noexcept {
 }
 
 TThrRefBase::~TThrRefBase() = default;
+
+[[noreturn]] void NDetail::NullDerefenceThrowImpl() {
+    ythrow yexception{} << "nullptr dereference";
+}
diff --git a/util/generic/ptr.h b/util/generic/ptr.h
index 625418ccdb0..cf28d0bfd2c 100644
--- a/util/generic/ptr.h
+++ b/util/generic/ptr.h
@@ -100,6 +100,10 @@ private:
     static void DoDestroy(void* t) noexcept;
 };
 
+namespace NDetail {
+    [[noreturn]] void NullDerefenceThrowImpl();
+} // namespace NDetail
+
 template <class Base, class T>
 class TPointerCommon {
 public:
@@ -116,6 +120,18 @@ public:
         return ptr;
     }
 
+    inline typename std::add_lvalue_reference<T>::type GetRef() const {
+        T* ptr = AsT();
+        if (Y_UNLIKELY(!ptr)) {
+            NDetail::NullDerefenceThrowImpl();
+        }
+        if constexpr (std::is_void<T>::value) {
+            return;
+        } else {
+            return *ptr;
+        }
+    }
+
 #ifndef __cpp_impl_three_way_comparison
     template <class C>
     inline bool operator==(const C& p) const noexcept {
diff --git a/util/generic/ptr_ut.cpp b/util/generic/ptr_ut.cpp
index 8f72cee5219..e6a4a7837c0 100644
--- a/util/generic/ptr_ut.cpp
+++ b/util/generic/ptr_ut.cpp
@@ -36,6 +36,7 @@ class TPointerTest: public TTestBase {
     UNIT_TEST(TestRefCountedPtrsInHashSet);
     UNIT_TEST(TestSharedPtrDowncast);
     UNIT_TEST(TestStdCompatibility);
+    UNIT_TEST(TestGetRef);
     UNIT_TEST_SUITE_END();
 
 private:
@@ -91,6 +92,7 @@ private:
     void TestRefCountedPtrsInHashSet();
     void TestSharedPtrDowncast();
     void TestStdCompatibility();
+    void TestGetRef();
 };
 
 UNIT_TEST_SUITE_REGISTRATION(TPointerTest);
@@ -962,3 +964,30 @@ void TPointerTest::TestStdCompatibility() {
         UNIT_ASSERT_VALUES_EQUAL(ptr.get(), ptr.Get());
     }
 }
+
+void TPointerTest::TestGetRef() {
+    {
+        TSimpleSharedPtr<int> ptr = MakeSimpleShared<int>(5);
+        UNIT_ASSERT_TYPES_EQUAL(decltype(ptr.GetRef()), int&);
+        UNIT_ASSERT_VALUES_EQUAL(ptr.GetRef(), 5);
+        ptr.GetRef() += 5;
+        UNIT_ASSERT_VALUES_EQUAL(ptr.GetRef(), 10);
+    }
+    {
+        THolder<const int> ptr = MakeHolder<int>(5);
+        UNIT_ASSERT_TYPES_EQUAL(decltype(ptr.GetRef()), const int&);
+        UNIT_ASSERT_VALUES_EQUAL(ptr.GetRef(), 5);
+    }
+    {
+        THolder<const int> ptr;
+        UNIT_ASSERT_EXCEPTION(ptr.GetRef(), yexception);
+    }
+
+    {
+        THolder<void, TNoAction> ptr((void*)10);
+        UNIT_ASSERT_TYPES_EQUAL(decltype(ptr.GetRef()), void);
+        ptr.GetRef();
+        ptr = {};
+        UNIT_ASSERT_EXCEPTION(ptr.GetRef(), yexception);
+    }
+}