clang-tidy/bugprone/StringviewNullptrCheck.h

0001 //===--- StringviewNullptrCheck.h - clang-tidy ------------------*- C++ -*-===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008
0009 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_STRINGVIEWNULLPTRCHECK_H
0010 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_STRINGVIEWNULLPTRCHECK_H
0011
0012 #include "../utils/TransformerClangTidyCheck.h"
0013
0014 namespace clang::tidy::bugprone {
0015
0016 /// Checks for various ways that the `const CharT*` constructor of
0017 /// `std::basic_string_view` can be passed a null argument and replaces them
0018 /// with the default constructor in most cases. For the comparison operators,
0019 /// braced initializer list does not compile so instead a call to `.empty()` or
0020 /// the empty string literal are used, where appropriate.
0021 ///
0022 /// This prevents code from invoking behavior which is unconditionally
0023 /// undefined. The single-argument `const CharT*` constructor does not check
0024 /// for the null case before dereferencing its input. The standard is slated to
0025 /// add an explicitly-deleted overload to catch some of these cases:
0026 /// wg21.link/p2166
0027 ///
0028 /// To catch the additional cases of `NULL` (which expands to `__null`) and
0029 /// `0`, first run the ``modernize-use-nullptr`` check to convert the callers
0030 /// to `nullptr`.
0031 ///
0032 /// For the user-facing documentation see:
0033 /// http://clang.llvm.org/extra/clang-tidy/checks/bugprone/stringview-nullptr.html
0034 class StringviewNullptrCheck : public utils::TransformerClangTidyCheck {
0035 public:
0036   StringviewNullptrCheck(StringRef Name, ClangTidyContext *Context);
0037
0038   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
0039     return LangOpts.CPlusPlus17;
0040   }
0041 };
0042
0043 } // namespace clang::tidy::bugprone
0044
0045 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_STRINGVIEWNULLPTRCHECK_H