Hotfix for rosidl cpp visibility header addition (#371)

Author: calderpg-tri

bazel_ros2_rules/ros2/rosidl.bzl

@@ -66,16 +66,92 @@ def _rosidl_generate_genrule_impl(ctx):
     args.add(ctx.attr.group)
     args.add_all(ctx.files.interfaces, map_each = _as_idl_tuple)
     inputs = ctx.files.interfaces + ctx.files.includes
+
+    expected_outputs = []
+    cpp_visibility_header_file = None
+
+    # The cpp visibility header is not generated by rosidl generate, so we must
+    # handle its generation separately.
+    for generated_source in ctx.outputs.generated_sources:
+        if "cpp__visibility_control.hpp" in generated_source.path:
+            cpp_visibility_header_file = generated_source
+        else:
+            expected_outputs.append(generated_source)
+
     ctx.actions.run_shell(
         tools = [ctx.executable._tool],
         arguments = [args],
         inputs = inputs,
         command = "{} $@ > /dev/null".format(
             ctx.executable._tool.path,
         ),
-        outputs = ctx.outputs.generated_sources,
+        outputs = expected_outputs,
     )
 
+    # This is a temporary hack to get the build working again. This should be
+    # redone so that the real template file from the ROS distribution is used,
+    # rather than our adaptation below.
+    # TODO(calderpg-tri) Replace this hack.
+    if cpp_visibility_header_file != None:
+        # This template is adapted directly from the mentioned template file.
+        cpp_visibility_header_template = (
+            """
+// generated from rosidl_generator_cpp/resource/rosidl_generator_cpp__visibility_control.hpp.in
+// generated code does not contain a copyright notice
+
+#ifndef {package_name_upper}__MSG__ROSIDL_GENERATOR_CPP__VISIBILITY_CONTROL_HPP_
+#define {package_name_upper}__MSG__ROSIDL_GENERATOR_CPP__VISIBILITY_CONTROL_HPP_
+
+#ifdef __cplusplus
+extern "C"
+{{
+#endif
+
+// This logic was borrowed (then namespaced) from the examples on the gcc wiki:
+//     https://gcc.gnu.org/wiki/Visibility
+
+#if defined _WIN32 || defined __CYGWIN__
+  #ifdef __GNUC__
+    #define ROSIDL_GENERATOR_CPP_EXPORT_{package_name} __attribute__ ((dllexport))
+    #define ROSIDL_GENERATOR_CPP_IMPORT_{package_name} __attribute__ ((dllimport))
+  #else
+    #define ROSIDL_GENERATOR_CPP_EXPORT_{package_name} __declspec(dllexport)
+    #define ROSIDL_GENERATOR_CPP_IMPORT_{package_name} __declspec(dllimport)
+  #endif
+  #ifdef ROSIDL_GENERATOR_CPP_BUILDING_DLL_{package_name}
+    #define ROSIDL_GENERATOR_CPP_PUBLIC_{package_name} ROSIDL_GENERATOR_CPP_EXPORT_{package_name}
+  #else
+    #define ROSIDL_GENERATOR_CPP_PUBLIC_{package_name} ROSIDL_GENERATOR_CPP_IMPORT_{package_name}
+  #endif
+#else
+  #define ROSIDL_GENERATOR_CPP_EXPORT_{package_name} __attribute__ ((visibility("default")))
+  #define ROSIDL_GENERATOR_CPP_IMPORT_{package_name}
+  #if __GNUC__ >= 4
+    #define ROSIDL_GENERATOR_CPP_PUBLIC_{package_name} __attribute__ ((visibility("default")))
+  #else
+    #define ROSIDL_GENERATOR_CPP_PUBLIC_{package_name}
+  #endif
+#endif
+
+#ifdef __cplusplus
+}}
+#endif
+
+#endif  // {package_name_upper}__MSG__ROSIDL_GENERATOR_CPP__VISIBILITY_CONTROL_HPP_
+"""  # noqa
+        )
+
+        package_name = str(ctx.attr.group)
+        package_name_upper = package_name.upper()
+
+        ctx.actions.write(
+            output = cpp_visibility_header_file,
+            content = cpp_visibility_header_template.format(
+                package_name = package_name,
+                package_name_upper = package_name_upper,
+            ),
+        )
+
 rosidl_generate_genrule = rule(
     attrs = dict(
         generated_sources = attr.output_list(mandatory = True),
@@ -492,7 +568,8 @@ def rosidl_cc_library(
     """
     include, root = _deduce_source_paths(group, "cpp")
 
-    generated_cc_headers = []
+    visibility_header = "msg/rosidl_generator_cpp__visibility_control.hpp"
+    generated_cc_headers = ["{}/{}".format(root, visibility_header)]
     for ifc in interfaces:
         parent, basename = _deduce_source_parts(ifc)
         generated_cc_headers.append(
@@ -507,6 +584,9 @@ def rosidl_cc_library(
         generated_cc_headers.append(
             "{}/{}/detail/{}__traits.hpp".format(root, parent, basename),
         )
+        generated_cc_headers.append(
+            "{}/{}/detail/{}__type_support.hpp".format(root, parent, basename),
+        )
 
     rosidl_generate_genrule(
         name = _make_private_name(name, "_gen"),