feat(tidy): Add new fairmq-tidy tool

fairmq/tidy/Tool.h

@@ -0,0 +1,76 @@
+/********************************************************************************
+ *    Copyright (C) 2021 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH    *
+ *                                                                              *
+ *              This software is distributed under the terms of the             *
+ *              GNU Lesser General Public Licence (LGPL) version 3,             *
+ *                  copied verbatim in the file "LICENSE"                       *
+ ********************************************************************************/
+
+#ifndef FAIR_MQ_TIDY_TOOL
+#define FAIR_MQ_TIDY_TOOL
+
+#include <clang/ASTMatchers/ASTMatchFinder.h>
+#include <clang/Basic/FileManager.h>
+#include <clang/Tooling/CompilationDatabase.h>
+#include <clang/Tooling/Tooling.h>
+#include <fairmq/tidy/ModernizeNonNamespacedTypes.h>
+#include <string>
+
+namespace fair::mq::tidy {
+
+// Getting up to speed, read this:
+// https://clang.llvm.org/docs/LibTooling.html
+// https://clang.llvm.org/docs/IntroductionToTheClangAST.html
+// Watch https://www.youtube.com/watch?v=VqCkCDFLSsc !!!
+//
+// optional, but helpful:
+// https://static.linaro.org/connect/yvr18/presentations/yvr18-223.pdf
+// https://steveire.wordpress.com/2018/11/20/composing-ast-matchers-in-clang-tidy/
+// https://www.goldsborough.me/c++/clang/llvm/tools/2017/02/24/00-00-06-emitting_diagnostics_and_fixithints_in_clang_tools/
+// https://steveire.com/CodeDive2018Presentation.pdf
+//
+// reference (no built-in search, however google will find things):
+// https://clang.llvm.org/doxygen/
+//
+// Note: Implementing a standalone tool will impose double PP and parsing cost if one also
+// runs clang-tidy. At the moment, one cannot extend clang-tidy with new checks without
+// recompiling clang-tidy. In principle llvm-project/clang-extra-tools/clang-tidy
+// has install rules, but Fedora is not packaging them which is likely due to their
+// unstable state (lots of comments aka todo, fixme, refactor etc). Also, it seems
+// focus has shifted towards implementing the
+// https://microsoft.github.io/language-server-protocol/
+// via https://clangd.llvm.org/ which includes clang-tidy, but also does not have
+// an extension/plugin interface for third-party checks yet AFAICS.
+
+struct Tool
+{
+    static auto run(clang::tooling::CompilationDatabase const &compilations,
+                    clang::ArrayRef<std::string> sources) -> int
+    {
+        using namespace clang;
+
+        // compose all checks in a single match finder
+        ast_matchers::MatchFinder finder;
+        ModernizeNonNamespacedTypes check1(finder);
+
+        // configure the clang tool
+        tooling::ClangTool tool(compilations, sources);
+        tool.appendArgumentsAdjuster(
+            [](tooling::CommandLineArguments const &_args, StringRef /*file*/) {
+                tooling::CommandLineArguments args(_args);
+                // TODO add only if cdb was generated with GCC
+                args.emplace(args.begin() + 1, "-I/usr/lib64/clang/12.0.0/include");
+                // TODO add only if missing
+                args.emplace(args.begin() + 1, "-std=c++17");
+                args.emplace_back("-Wno-everything");
+                return args;
+            });
+
+        // run checks on given files
+        return tool.run(clang::tooling::newFrontendActionFactory(&finder).get());
+    }
+};
+
+}   // namespace fair::mq::tidy
+
+#endif /* FAIR_MQ_TIDY_TOOL */