inject BOM into generated C/C++ code when necessary

Signed-off-by: Dirk Thomas <[email protected]>
ros2 · Jul 25, 2019 · 18f022b · 18f022b
1 parent d5e21dc
commit 18f022b
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Showing 3 changed files with 38 additions and 5 deletions.
diff --git a/rosidl_cmake/rosidl_cmake/__init__.py b/rosidl_cmake/rosidl_cmake/__init__.py
@@ -48,7 +48,10 @@ def get_newest_modification_time(target_dependencies):
     return newest_timestamp
 
 
-def generate_files(generator_arguments_file, mapping, additional_context=None, keep_case=False):
+def generate_files(
+    generator_arguments_file, mapping, additional_context=None,
+    keep_case=False, post_process_callback=None
+):
     args = read_generator_arguments(generator_arguments_file)
 
     template_basepath = pathlib.Path(args['template_dir'])
@@ -82,7 +85,8 @@ def generate_files(generator_arguments_file, mapping, additional_context=None, k
                 expand_template(
                     os.path.basename(template_file), data,
                     generated_file, minimum_timestamp=latest_target_timestamp,
-                    template_basepath=template_basepath)
+                    template_basepath=template_basepath,
+                    post_process_callback=post_process_callback)
         except Exception as e:
             print(
                 'Error processing idl file: ' +
@@ -110,7 +114,7 @@ def get_template_path(template_name):
 
 def expand_template(
     template_name, data, output_file, minimum_timestamp=None,
-    template_basepath=None
+    template_basepath=None, post_process_callback=None
 ):
     # in the legacy API the first argument was the path to the template
     if template_basepath is None:
@@ -155,6 +159,9 @@ def expand_template(
     content = output.getvalue()
     interpreter.shutdown()
 
+    if post_process_callback:
+        content = post_process_callback(content)
+
     # only overwrite file if necessary
     # which is either when the timestamp is too old or when the content is different
     if os.path.exists(output_file):

diff --git a/rosidl_generator_c/rosidl_generator_c/__init__.py b/rosidl_generator_c/rosidl_generator_c/__init__.py
@@ -34,7 +34,20 @@ def generate_c(generator_arguments_file):
         'idl__struct.h.em': '%s__struct.h',
         'idl__type_support.h.em': '%s__type_support.h',
     }
-    generate_files(generator_arguments_file, mapping)
+    generate_files(
+        generator_arguments_file, mapping,
+        post_process_callback=prefix_with_bom_if_necessary)
+
+
+def prefix_with_bom_if_necessary(content):
+    try:
+        content.encode('ASCII')
+    except UnicodeError:
+        prefix = '\ufeff' + \
+            '// NOLINT: This file starts with a BOM ' + \
+            'since it contain non-ASCII characters\n'
+        content = prefix + content
+    return content
 
 
 BASIC_IDL_TYPES_TO_C = {

diff --git a/rosidl_generator_cpp/rosidl_generator_cpp/__init__.py b/rosidl_generator_cpp/rosidl_generator_cpp/__init__.py
@@ -34,7 +34,20 @@ def generate_cpp(generator_arguments_file):
         'idl__struct.hpp.em': '%s__struct.hpp',
         'idl__traits.hpp.em': '%s__traits.hpp',
     }
-    generate_files(generator_arguments_file, mapping)
+    generate_files(
+        generator_arguments_file, mapping,
+        post_process_callback=prefix_with_bom_if_necessary)
+
+
+def prefix_with_bom_if_necessary(content):
+    try:
+        content.encode('ASCII')
+    except UnicodeError:
+        prefix = '\ufeff' + \
+            '// NOLINT: This file starts with a BOM ' + \
+            'since it contain non-ASCII characters\n'
+        content = prefix + content
+    return content
 
 
 MSG_TYPE_TO_CPP = {