================ @@ -0,0 +1,80 @@ +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#ifndef LLDB_UTILITY_NONNULLSHAREDPTR_H +#define LLDB_UTILITY_NONNULLSHAREDPTR_H + +#include <memory> +#include <utility> + +namespace lldb_private { + +/// A non-nullable shared pointer that always holds a valid object. +/// +/// NonNullSharedPtr is a smart pointer wrapper around std::shared_ptr that +/// guarantees the pointer is never null. +/// +/// This class is used for enforcing invariants at the type level and +/// eliminating entire classes of null pointer bugs. +/// +/// @tparam T The type of object to manage. Must be default-constructible. +template <typename T> class NonNullSharedPtr : private std::shared_ptr<T> { + using Base = std::shared_ptr<T>; + +public: + NonNullSharedPtr(const std::shared_ptr<T> &t) + : Base(t ? t : std::make_shared<T>()) { + assert(t && "NonNullSharedPtr initialized from NULL shared_ptr"); + } + + NonNullSharedPtr(std::shared_ptr<T> &&t) + : Base(t ? std::move(t) : std::make_shared<T>()) { + // Can't assert on t as it's been moved-from. + } + + NonNullSharedPtr(const NonNullSharedPtr &other) : Base(other) {} + + NonNullSharedPtr(NonNullSharedPtr &&other) : Base(std::move(other)) {} + + NonNullSharedPtr &operator=(const NonNullSharedPtr &other) { ---------------- felipepiovezan wrote:
is this different from `= default`? Likewise for the below https://github.com/llvm/llvm-project/pull/168624 _______________________________________________ lldb-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
