*: introduce not_null as a submodule (#8802)

close #8933

.gitmodules

@@ -143,3 +143,6 @@
 [submodule "contrib/simdjson"]
 	path = contrib/simdjson
 	url = https://github.com/simdjson/simdjson.git
+[submodule "contrib/not_null"]
+	path = contrib/not_null
+	url = https://github.com/bitwizeshift/not_null.git

dbms/CMakeLists.txt

@@ -153,6 +153,7 @@ else ()
     install (TARGETS dbms LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR} COMPONENT tiflash)
 endif ()
 
+target_include_directories(dbms PUBLIC ${TiFlash_SOURCE_DIR}/contrib/not_null/include)
 target_include_directories(dbms PUBLIC "${TIFLASH_PROXY_INCLUDE_DIR}")
 
 if (CMAKE_BUILD_TYPE_UC STREQUAL "RELEASE" OR CMAKE_BUILD_TYPE_UC STREQUAL "RELWITHDEBINFO" OR CMAKE_BUILD_TYPE_UC STREQUAL "MINSIZEREL")

dbms/src/Common/NotNull.h

@@ -0,0 +1,54 @@
+// Copyright 2024 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <Common/Exception.h>
+
+#include <memory>
+#include <not_null.hpp>
+
+namespace DB
+{
+
+template <typename T>
+using NotNull = cpp::bitwizeshift::not_null<T>;
+
+// It involves an extra check when constructing,
+// if we can't tell if `ptr` is nullptr at compile time.
+template <class T>
+auto newNotNull(T && ptr)
+{
+    return cpp::bitwizeshift::check_not_null(std::move(ptr));
+}
+
+template <class T, class... Args>
+auto makeNotNullShared(Args &&... args)
+{
+    return cpp::bitwizeshift::assume_not_null(std::make_shared<T>(std::forward<Args>(args)...));
+}
+
+template <class T, class... Args>
+auto makeNotNullUnique(Args &&... args)
+{
+    return cpp::bitwizeshift::assume_not_null(std::make_unique<T>(std::forward<Args>(args)...));
+}
+
+template <typename T>
+using NotNullShared = cpp::bitwizeshift::not_null<std::shared_ptr<T>>;
+
+template <typename T>
+using NotNullUnique = cpp::bitwizeshift::not_null<std::unique_ptr<T>>;
+
+}; // namespace DB