Make case fallthrough explicit (#153)

* Make case fallthrough explicit

rmw_cyclonedds_cpp/CMakeLists.txt

@@ -22,7 +22,7 @@ if(NOT CMAKE_CXX_STANDARD)
 endif()
 
 if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-  add_compile_options(-Wall -Wextra -Wpedantic)
+  add_compile_options(-Wall -Wextra -Wpedantic -Wimplicit-fallthrough)
 endif()
 
 find_package(ament_cmake_ros REQUIRED)

rmw_cyclonedds_cpp/src/fallthrough_macro.hpp

@@ -0,0 +1,29 @@
+// Copyright 2019 ADLINK Technology via Rover Robotics and Dan Rose
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef FALLTHROUGH_MACRO_HPP_
+#define FALLTHROUGH_MACRO_HPP_
+
+#if __has_cpp_attribute(fallthrough) || (__cplusplus >= 201603L)
+// C++17
+#define FALLTHROUGH [[fallthrough]]
+#elif __has_cpp_attribute(clang::fallthrough)
+// Clang
+#define FALLTHROUGH [[clang::fallthrough]]
+#else
+// gcc
+#define FALLTHROUGH /* fallthrough */
+#endif
+
+#endif  // FALLTHROUGH_MACRO_HPP_

rmw_cyclonedds_cpp/src/rmw_node.cpp

@@ -45,6 +45,7 @@
 #include "rmw/sanity_checks.h"
 #include "rmw/validate_node_name.h"
 
+#include "fallthrough_macro.hpp"
 #include "Serialization.hpp"
 #include "rmw/impl/cpp/macros.hpp"
 
@@ -354,12 +355,16 @@ extern "C" rmw_ret_t rmw_set_log_severity(rmw_log_severity_t severity)
       return RMW_RET_INVALID_ARGUMENT;
     case RMW_LOG_SEVERITY_DEBUG:
       mask |= DDS_LC_DISCOVERY | DDS_LC_THROTTLE | DDS_LC_CONFIG;
+      FALLTHROUGH;
     case RMW_LOG_SEVERITY_INFO:
       mask |= DDS_LC_INFO;
+      FALLTHROUGH;
     case RMW_LOG_SEVERITY_WARN:
       mask |= DDS_LC_WARNING;
+      FALLTHROUGH;
     case RMW_LOG_SEVERITY_ERROR:
       mask |= DDS_LC_ERROR;
+      FALLTHROUGH;
     case RMW_LOG_SEVERITY_FATAL:
       mask |= DDS_LC_FATAL;
   }