Register language of typesupport for rmw implementation (ros2#63)

Add macros for getting type support for a particular language for an rmw implementation

rmw/cmake/get_rmw_typesupport.cmake

@@ -1,4 +1,4 @@
-# Copyright 2015 Open Source Robotics Foundation, Inc.
+# Copyright 2015-2016 Open Source Robotics Foundation, Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -13,18 +13,29 @@
 # limitations under the License.
 
 #
-# Get the type support package name for specific ROS middleware implementation.
+# Get the type support package names for a specific RMW implementation.
 #
-# :param rmw_implementation: the package name of the ROS middleware
-#   implementation
+# :param var: the output variable name containing the package names
+# :type var: list of strings
+# :param rmw_implementation: the package name of the RMW implementation
 # :type rmw_implementation: string
+# :param LANGUAGE: Optional flag for the language of the type support to get.
+#   If language is omitted, type supports for all languages are returned.
+# :type LANGUAGE: string
 #
 # @public
 #
-macro(get_rmw_typesupport var rmw_implementation)
-  if(NOT "${ARGN} " STREQUAL " ")
-    message(FATAL_ERROR "get_rmw_typesupport() called with unused arguments: ${ARGN}")
+function(get_rmw_typesupport var rmw_implementation)
+  cmake_parse_arguments(ARG "" "LANGUAGE" "" ${ARGN})
+  if(ARG_UNPARSED_ARGUMENTS)
+    message(FATAL_ERROR "get_rmw_typesupport() called with unused "
+      "arguments: ${ARG_UNPARSED_ARGUMENTS}")
   endif()
-
-  ament_index_get_resource(${var} "rmw_implementation" "${rmw_implementation}")
-endmacro()
+  set(resource_type "rmw_typesupport")
+  if(NOT "${ARG_LANGUAGE} " STREQUAL " ")
+    string(TOLOWER "${ARG_LANGUAGE}" ARG_LANGUAGE)
+    set(resource_type "${resource_type}_${ARG_LANGUAGE}")
+  endif()
+  ament_index_get_resource(resource "${resource_type}" "${rmw_implementation}")
+  set(${var} "${resource}" PARENT_SCOPE)
+endfunction()

rmw/cmake/register_rmw_implementation.cmake

@@ -15,17 +15,52 @@
 #
 # Register the current package as a ROS middleware implementation.
 #
-# :param typesupport_package_name: the package name providing type support for
-#   for the registered RMW implementation
-# :type typesupport_package_name: string
+# A valid usage of this function is
+# register_rmw_implementation("c:rosidl_typesupport_introspection_c"
+#                             "cpp:rosidl_typesupport_introspection_cpp")
+# If there were multiple valid typesupports for one language in a package,
+# they would be separated by colons, e.g.
+# register_rmw_implementation(
+#   "cpp:rosidl_typesupport_a_cpp:rosidl_typesupport_b_cpp")
+# If there are multiple inputs with the same language flag (first entry) the
+# function will error.
+# :param ARGN: a list of <language:typesupport> tuples where language is the
+# language of the typesupport package and typesupport is the name of the
+# package.
+# :type ARGN: a list of strings
 #
 # @public
 #
-macro(register_rmw_implementation typesupport_package_name)
-  if(NOT "${ARGN} " STREQUAL " ")
-    message(FATAL_ERROR "register_rmw_implementation() called with "
-      "unused arguments: ${ARGN}")
-  endif()
+function(register_rmw_implementation)
+  set(all_typesupports "")
+  set(language_labels "")
 
-  ament_index_register_resource("rmw_implementation" CONTENT "${typesupport_package_name}")
-endmacro()
+  foreach(arg_raw ${ARGN})
+    # replace colon with semicolon to turn into a list
+    string(REPLACE ":" ";" arg "${arg_raw}")
+    list(LENGTH arg arg_length)
+    if(arg_length LESS 1)
+      message(FATAL_ERROR
+        "register_rmw_implementation() called with invalid input: ${arg_raw}")
+    endif()
+    list(GET arg 0 language_label)
+    list(REMOVE_AT arg 0)
+    string(TOLOWER "${language_label}" language_label)
+    # Cache the existing languages labels found (so that we don't have to
+    # check the ament index twice every loop) and error if we've already
+    # encountered the language
+    list(FIND language_labels "${language_label}" label_found)
+    if(NOT ${label_found} EQUAL -1)
+      message(FATAL_ERROR
+        "register_rmw_implementation() got language '${language_label}' "
+        "multiple times")
+    endif()
+    list(APPEND language_labels "${language_label}")
+    ament_index_register_resource(
+      "rmw_typesupport_${language_label}" CONTENT "${arg}"
+    )
+    list_append_unique(all_typesupports "${arg}")
+  endforeach()
+
+  ament_index_register_resource("rmw_typesupport" CONTENT "${all_typesupports}")
+endfunction()

rmw_implementation_cmake/cmake/get_available_rmw_implementations.cmake

@@ -19,7 +19,7 @@
 # :type var: list of strings
 #
 function(get_available_rmw_implementations var)
-  ament_index_get_resources(middleware_implementations "rmw_implementation")
+  ament_index_get_resources(middleware_implementations "rmw_typesupport")
   if(DEFINED middleware_implementations)
     list(SORT middleware_implementations)
   endif()