Cleanup of CompileCommands::get_arguments and disables more outside header warnings for header files

src/compile_commands.cc

@@ -81,10 +81,11 @@ CompileCommands::CompileCommands(const boost::filesystem::path &build_path) {
 }
 
 std::vector<std::string> CompileCommands::get_arguments(const boost::filesystem::path &build_path, const boost::filesystem::path &file_path) {
+  std::vector<std::string> arguments;
+  if(!build_path.empty()) {
     clangmm::CompilationDatabase db(build_path.string());
     clangmm::CompileCommands commands(file_path.string(), db);
-  std::vector<clangmm::CompileCommand> cmds = commands.get_commands();
-  std::vector<std::string> arguments;
+    auto cmds = commands.get_commands();
     for (auto &cmd : cmds) {
       auto cmd_arguments = cmd.get_arguments();
       bool ignore_next=false;
@@ -100,6 +101,7 @@ std::vector<std::string> CompileCommands::get_arguments(const boost::filesystem:
         arguments.emplace_back(cmd_arguments[c]);
       }
     }
+  }
   auto clang_version_string=clangmm::to_string(clang_getClangVersion());
   const static std::regex clang_version_regex("^[A-Za-z ]+([0-9.]+).*$");
   std::smatch sm;
@@ -125,13 +127,11 @@ std::vector<std::string> CompileCommands::get_arguments(const boost::filesystem:
      extension!=".c")
     arguments.emplace_back("-xc++");
   
-  if(extension.empty()) { // For std headers
-    arguments.emplace_back("-xc++");
-    arguments.emplace_back("-w"); // Disable all warnings
-  }
-  
-  if((extension.size()>1 && extension[1]=='h') || extension==".tcc")
+  if(extension.empty() || (1<extension.size() && extension[1]=='h') || extension==".tcc") {
     arguments.emplace_back("-Wno-pragma-once-outside-header");
+    arguments.emplace_back("-Wno-pragma-system-header-outside-header");
+    arguments.emplace_back("-Wno-include-next-outside-header");
+  }
   
   if(!build_path.empty()) {
     arguments.emplace_back("-working-directory");