From a7495db03f42661b05ca5341ef042f154df0bd1a Mon Sep 17 00:00:00 2001
From: erki <skull132@skullnet.me>
Date: Wed, 25 Oct 2023 11:39:55 +0300
Subject: [PATCH] Utility: add notnull

---
 Tests/CMakeLists.txt            |  1 +
 Tests/notnull.cpp               | 59 +++++++++++++++++++++++++++++++++
 Utility/Inc/utility_notnull.hpp | 51 ++++++++++++++++++++++++++++
 3 files changed, 111 insertions(+)
 create mode 100644 Tests/notnull.cpp
 create mode 100644 Utility/Inc/utility_notnull.hpp

diff --git a/Tests/CMakeLists.txt b/Tests/CMakeLists.txt
index 69185ad..66073d1 100644
--- a/Tests/CMakeLists.txt
+++ b/Tests/CMakeLists.txt
@@ -32,6 +32,7 @@ add_executable(tests
     bytes.cpp
     filters.cpp
     cpptick.cpp
+    notnull.cpp
 )
 
 target_link_libraries(tests
diff --git a/Tests/notnull.cpp b/Tests/notnull.cpp
new file mode 100644
index 0000000..6157cc6
--- /dev/null
+++ b/Tests/notnull.cpp
@@ -0,0 +1,59 @@
+//
+// Created by erki on 25/10/23.
+//
+
+#include <catch2/catch.hpp>
+
+#include <atomic>
+
+#ifdef NDEBUG
+#undef NDEBUG
+#define NDEBUG_WAS_DEFINED
+#endif
+
+#include "utility_assert.hpp"
+#include "utility_notnull.hpp"
+
+#ifdef NDEBUG_WAS_DEFINED
+#define NDEBUG
+#endif
+
+namespace
+{
+
+std::atomic<bool> assert_flag = false;
+
+void assertCallback(const char*, const char*, const int)
+{
+  assert_flag = true;
+}
+
+}// namespace
+
+TEST_CASE("Assert is tripped if nullptr passed.", "[utility],[notnull]")
+{
+  assert_flag = false;
+  Utility::Assert::setHandler(assertCallback);
+  REQUIRE(assert_flag == false);
+
+  auto call = [](Utility::NotNull<int> i) -> void {};
+
+  call(nullptr);
+  CHECK(assert_flag == true);
+}
+
+TEST_CASE("Assert is not tripped if valid pointer is passed.", "[utility],[notnull]")
+{
+  assert_flag = false;
+  Utility::Assert::setHandler(assertCallback);
+  REQUIRE(assert_flag == false);
+
+  auto call = [](Utility::NotNull<int> i) -> int {
+    return *i;
+  };
+
+  int a = 5;
+  const int test = call(&a);
+  CHECK(assert_flag == false);
+  CHECK(a == test);
+}
diff --git a/Utility/Inc/utility_notnull.hpp b/Utility/Inc/utility_notnull.hpp
new file mode 100644
index 0000000..9ee984e
--- /dev/null
+++ b/Utility/Inc/utility_notnull.hpp
@@ -0,0 +1,51 @@
+//
+// Created by erki on 25/10/23.
+//
+
+#pragma once
+
+#include "utility_assert.hpp"
+
+namespace Utility
+{
+
+template<typename T>
+struct NotNull
+{
+  NotNull(T* ptr)
+      : ptr_(ptr)
+  {
+    SKULLC_ASSERT_DEBUG(ptr_ != nullptr);
+  }
+
+  NotNull() = delete;
+  NotNull(const NotNull&) = delete;
+  NotNull(NotNull&&) = delete;
+  NotNull& operator=(const NotNull&) = delete;
+  NotNull& operator=(NotNull&&) = delete;
+
+  const T& operator*() const
+  {
+    return *ptr_;
+  }
+
+  T& operator*()
+  {
+    return *ptr_;
+  }
+
+  const T* operator->() const noexcept
+  {
+    return ptr_;
+  }
+
+  T* operator->() noexcept
+  {
+    return ptr_;
+  }
+
+private:
+  T* ptr_;
+};
+
+}// namespace Utility