clang-tidy module: add #pragma once check

Co-Authored-by: Kyle Edwards <kyle.edwards@kitware.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/Utilities/ClangTidyModule/UsePragmaOnceCheck.h b/Utilities/ClangTidyModule/UsePragmaOnceCheck.h
new file mode 100644
index 0000000..08c2099
--- /dev/null
+++ b/Utilities/ClangTidyModule/UsePragmaOnceCheck.h
@@ -0,0 +1,60 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+
+/* This code was originally taken from part of the Clang-Tidy LLVM project and
+ * modified for use with CMake under the following original license: */
+
+//===--- HeaderGuard.h - clang-tidy -----------------------------*- C++
+//-*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#pragma once
+
+#include <clang-tidy/ClangTidyCheck.h>
+#include <clang-tidy/utils/FileExtensionsUtils.h>
+
+namespace clang {
+namespace tidy {
+namespace cmake {
+
+/// Finds and replaces header guards with pragma once.
+/// The check supports these options:
+///   - `HeaderFileExtensions`: a semicolon-separated list of filename
+///     extensions of header files (The filename extension should not contain
+///     "." prefix). ";h;hh;hpp;hxx" by default.
+///
+///     For extension-less header files, using an empty string or leaving an
+///     empty string between ";" if there are other filename extensions.
+class UsePragmaOnceCheck : public ClangTidyCheck
+{
+public:
+  UsePragmaOnceCheck(StringRef Name, ClangTidyContext* Context)
+    : ClangTidyCheck(Name, Context)
+    , RawStringHeaderFileExtensions(Options.getLocalOrGlobal(
+        "HeaderFileExtensions", utils::defaultHeaderFileExtensions()))
+  {
+    utils::parseFileExtensions(RawStringHeaderFileExtensions,
+                               HeaderFileExtensions,
+                               utils::defaultFileExtensionDelimiters());
+  }
+  void storeOptions(ClangTidyOptions::OptionMap& Opts) override;
+  void registerPPCallbacks(const SourceManager& SM, Preprocessor* PP,
+                           Preprocessor* ModuleExpanderPP) override;
+
+  /// Returns ``true`` if the check should add pragma once to the file
+  /// if it has none.
+  virtual bool shouldSuggestToAddPragmaOnce(StringRef Filename);
+
+private:
+  std::string RawStringHeaderFileExtensions;
+  utils::FileExtensionsSet HeaderFileExtensions;
+};
+
+} // namespace cmake
+} // namespace tidy
+} // namespace clang