Message generation refactoring (#80)

Previously, only messages consisting of basic types and strings were supported. Now, all message types will work, including those that have fields of nested types, bounded types, or arrays.

Changes:
- The "rsext" library is deleted
- Unused messages in "rosidl_generator_rs" are deleted
- There is a new package, "rosidl_runtime_rs", see below
- The RMW-compatible messages from C, which do not require an extra conversion step, are exposed in addition to the "idiomatic" messages
- Publisher and subscription are changed to work with both idiomatic and rmw types, through the unifying `Message` trait

On `rosidl_runtime_rs`: This package is the successor of `rclrs_msg_utilities` package, but doesn't have much in common with it anymore.
It provides common types and functionality for messages. The `String` and `Sequence` types and their variants in that package essentially wrap C types from the `rosidl_runtime_c` package and C messages generated by the "rosidl_generator_c" package.
A number of functions and traits are implemented on these types, so that they feel as ergonomic as possible, for instance, a `seq!` macro for creating a sequence. There is also some documentation and doctests.

The memory for the (non-pretty) message types is managed by the C allocator.

Not yet implemented:
- long double
- constants
- Services/clients
- @verbatim comments
- ndarray for sequences/arrays of numeric types
- implementing `Eq`, `Ord` and `Hash` when a message contains no floats

rosidl_generator_rs/cmake/rosidl_generator_rs_generate_interfaces.cmake

@@ -36,13 +36,8 @@ set(_output_path
 set(_generated_extension_files "")
 set(_generated_common_rs_files "")
 
-set(_generated_c_files "")
-set(_generated_rs_files "")
-
 set(_generated_msg_rs_files "")
-set(_generated_msg_c_files "")
 set(_generated_srv_rs_files "")
-set(_generated_srv_c_files "")
 
 set(_has_msg FALSE)
 set(_has_srv FALSE)
@@ -110,8 +105,6 @@ endforeach()
 set(target_dependencies
   "${rosidl_generator_rs_BIN}"
   ${rosidl_generator_rs_GENERATOR_FILES}
-  "${rosidl_generator_rs_TEMPLATE_DIR}/msg.c.em"
-  "${rosidl_generator_rs_TEMPLATE_DIR}/srv.c.em"
   "${rosidl_generator_rs_TEMPLATE_DIR}/msg.rs.em"
   "${rosidl_generator_rs_TEMPLATE_DIR}/srv.rs.em"
   ${rosidl_generate_interfaces_ABS_IDL_FILES}
@@ -139,7 +132,7 @@ file(MAKE_DIRECTORY "${_output_path}")
 
 set(_target_suffix "__rs")
 
-set(CRATES_DEPENDENCIES "rclrs_msg_utilities = \"*\"")
+set(CRATES_DEPENDENCIES "rosidl_runtime_rs = \"*\"")
 foreach(_pkg_name ${rosidl_generate_interfaces_DEPENDENCY_PACKAGE_NAMES})
   find_package(${_pkg_name} REQUIRED)
   set(CRATES_DEPENDENCIES "${CRATES_DEPENDENCIES}\n${_pkg_name} = \"*\"")
@@ -162,117 +155,35 @@ set_property(
   ${_generated_extension_files}
   ${_generated_common_rs_files}
   ${_generated_msg_rs_files}
-  ${_generated_msg_c_files}
   ${_generated_srv_rs_files}
   PROPERTY GENERATED 1)
 
-set(_type_support_by_generated_c_files ${_type_support_by_generated_msg_c_files} ${_type_support_by_generated_srv_c_files})
-set(_generated_rs_files ${_generated_msg_rs_files} ${_generated_srv_rs_files})
-
 set(_rsext_suffix "__rsext")
 foreach(_typesupport_impl ${_typesupport_impls})
   find_package(${_typesupport_impl} REQUIRED)
 
-  set(_extension_compile_flags "")
-  if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-    set(_extension_compile_flags -Wall -Wextra)
-  endif()
-
-  set(_target_name "${PROJECT_NAME}__${_typesupport_impl}${_rsext_suffix}")
-
-  add_library(${_target_name} SHARED
-    ${_generated_extension_${_typesupport_impl}_files}
-  )
-  add_dependencies(
-    ${_target_name}
-    ${rosidl_generate_interfaces_TARGET}${_target_suffix}
-    ${rosidl_generate_interfaces_TARGET}__rosidl_typesupport_c
-  )
-
-  target_link_libraries(
-    ${_target_name}
-    ${PROJECT_NAME}__${_typesupport_impl}
-    ${rosidl_generate_interfaces_TARGET}__rosidl_generator_c
-  )
-
-  if (NOT $ENV{ROS_DISTRO} STREQUAL "rolling")
-    rosidl_target_interfaces(${_target_name}
-      ${rosidl_generate_interfaces_TARGET} rosidl_typesupport_c)
-  else()
-    rosidl_get_typesupport_target(rust_typesupport_target ${rosidl_generate_interfaces_TARGET} rosidl_typesupport_c)
-    target_link_libraries(${_target_name} ${rust_typesupport_target})
-  endif()
-
-  target_include_directories(${_target_name}
-    PUBLIC
-    ${CMAKE_CURRENT_BINARY_DIR}/rosidl_generator_c
-    ${CMAKE_CURRENT_BINARY_DIR}/rosidl_generator_rs
-  )
-
-  ament_target_dependencies(${_target_name}
-    "rosidl_runtime_c"
-    "rosidl_typesupport_c"
-    "rosidl_typesupport_interface"
-  )
-  foreach(_pkg_name ${rosidl_generate_interfaces_DEPENDENCY_PACKAGE_NAMES})
-    ament_target_dependencies(${_target_name}
-      ${_pkg_name}
-    )
-  endforeach()
-
-  add_dependencies(${_target_name}
-    ${rosidl_generate_interfaces_TARGET}__${_typesupport_impl}
-  )
-  ament_target_dependencies(${_target_name}
-    "rosidl_runtime_c"
-    "rosidl_generator_rs"
-  )
-
   if(NOT rosidl_generate_interfaces_SKIP_INSTALL)
     install(
       DIRECTORY "${_output_path}/rust"
       DESTINATION "share/${PROJECT_NAME}"
     )
-    install(TARGETS ${_target_name}
-      ARCHIVE DESTINATION lib
-      LIBRARY DESTINATION lib
-    )
-
-    configure_file("${rosidl_generator_rs_TEMPLATE_DIR}/Cargo.toml.in"
-      "share/${PROJECT_NAME}/rust/Cargo.toml"
-      @ONLY)
-
-    install(
-      FILES "${CMAKE_CURRENT_BINARY_DIR}/share/${PROJECT_NAME}/rust/Cargo.toml"
-      DESTINATION share/${PROJECT_NAME}/rust/
-    )
   endif()
 endforeach()
 
+configure_file("${rosidl_generator_rs_TEMPLATE_DIR}/Cargo.toml.in"
+  "share/${PROJECT_NAME}/rust/Cargo.toml"
+  @ONLY)
+
+install(
+  FILES "${CMAKE_CURRENT_BINARY_DIR}/share/${PROJECT_NAME}/rust/Cargo.toml"
+  DESTINATION share/${PROJECT_NAME}/rust/
+)
+
 if(BUILD_TESTING AND rosidl_generate_interfaces_ADD_LINTER_TESTS)
   if(
     NOT _generated_msg_rs_files STREQUAL "" OR
     NOT _generated_srv_rs_files STREQUAL ""
   )
-    find_package(ament_cmake_cppcheck REQUIRED)
-    ament_cppcheck(
-      TESTNAME "cppcheck_rosidl_generated_rs"
-      "${_output_path}")
-
-    find_package(ament_cmake_cpplint REQUIRED)
-    get_filename_component(_cpplint_root "${_output_path}" DIRECTORY)
-    ament_cpplint(
-      TESTNAME "cpplint_rosidl_generated_rs"
-      # the generated code might contain longer lines for templated types
-      MAX_LINE_LENGTH 999
-      ROOT "${_cpplint_root}"
-      "${_output_path}")
-
-    find_package(ament_cmake_uncrustify REQUIRED)
-    ament_uncrustify(
-      TESTNAME "uncrustify_rosidl_generated_rs"
-      # the generated code might contain longer lines for templated types
-      MAX_LINE_LENGTH 999
-      "${_output_path}")
+  # TODO(esteve): add linters for Rust files
   endif()
 endif()

rosidl_generator_rs/package.xml

@@ -10,11 +10,11 @@
 
   <buildtool_depend>ament_cmake</buildtool_depend>
 
-  <buildtool_depend>rclrs_msg_utilities</buildtool_depend>
+  <buildtool_depend>rosidl_runtime_rs</buildtool_depend>
 
   <buildtool_export_depend>ament_cmake</buildtool_export_depend>
   <buildtool_export_depend>rosidl_cmake</buildtool_export_depend>
-  <buildtool_export_depend>rclrs_msg_utilities</buildtool_export_depend>
+  <buildtool_export_depend>rosidl_runtime_rs</buildtool_export_depend>
   <buildtool_export_depend>rosidl_typesupport_c</buildtool_export_depend>
   <buildtool_export_depend>rosidl_typesupport_interface</buildtool_export_depend>
 

rosidl_generator_rs/resource/Cargo.toml.in

@@ -1,7 +1,7 @@
 [package]
 name = "@PROJECT_NAME@"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 libc = "0.2"

rosidl_generator_rs/resource/lib.rs.em

@@ -1,10 +1,7 @@
-extern crate rclrs_msg_utilities;
-extern crate libc;
-
 @[if len(msg_specs) > 0]@
 pub mod msg;
 @[end if]@
 
 @[if len(srv_specs) > 0]@
 pub mod srv;
-@[end if]@
+@[end if]@