diff options
Diffstat (limited to 'src/mongo/util')
-rw-r--r-- | src/mongo/util/auto_clear_ptr.h | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/src/mongo/util/auto_clear_ptr.h b/src/mongo/util/auto_clear_ptr.h new file mode 100644 index 00000000000..7ea2b8254c8 --- /dev/null +++ b/src/mongo/util/auto_clear_ptr.h @@ -0,0 +1,58 @@ +/** + * Copyright (C) 2020-present MongoDB, Inc. + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the Server Side Public License, version 1, + * as published by MongoDB, Inc. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * Server Side Public License for more details. + * + * You should have received a copy of the Server Side Public License + * along with this program. If not, see + * <http://www.mongodb.com/licensing/server-side-public-license>. + * + * As a special exception, the copyright holders give permission to link the + * code of portions of this program with the OpenSSL library under certain + * conditions as described in each individual source file and distribute + * linked combinations including the program with the OpenSSL library. You + * must comply with the Server Side Public License in all respects for + * all of the code used other than as permitted herein. If you modify file(s) + * with this exception, you may extend this exception to your version of the + * file(s), but you are not obligated to do so. If you do not wish to do so, + * delete this exception statement from your version. If you delete this + * exception statement from all source files in the program, then also delete + * it in the license file. + */ + +#pragma once + +#include <memory> + +namespace mongo { + +template <class Container> +class ClearDeleter { +public: + void operator()(Container* container) { + container->clear(); + } +}; + +/** + * A RAII style move-only pointer that calls clear() when going out of scope + */ +template <class Container> +using AutoClearPtr = std::unique_ptr<Container, ClearDeleter<Container>>; + +template <class Container> +auto makeAutoClearPtr(Container* container) { + // It should always be cleared when it is accessed + dassert(container); + dassert(container->empty()); + return AutoClearPtr<Container>{container, ClearDeleter<Container>{}}; +} + +} // namespace mongo |