Port embedSdf script from Ruby to Python3

- removes Ruby dependency (see gazebosim#274)
- improvements for cpplint checks (e.g. copyright header)

Signed-off-by: Bi0T1N <Bi0T1N@users.noreply.github.com>

Author: Bi0T1N

sdf/CMakeLists.txt

@@ -14,7 +14,7 @@ add_dependencies(schema schema1_9)
 # Generate the EmbeddedSdf.cc file, which contains all the supported SDF
 # descriptions in a map of strings. The parser.cc file uses EmbeddedSdf.hh.
 execute_process(
-  COMMAND ${RUBY} ${CMAKE_SOURCE_DIR}/sdf/embedSdf.rb
+  COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_SOURCE_DIR}/sdf/embedSdf.py
   WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}/sdf"
   OUTPUT_FILE "${PROJECT_BINARY_DIR}/src/EmbeddedSdf.cc"
 )

sdf/embedSdf.py

@@ -0,0 +1,147 @@
+#!/usr/bin/env python3
+from pathlib import Path
+
+""""Script for generating a C++ file that contains the content from all SDF files"""
+
+# The list of supported SDF specification versions. This will let us drop
+# versions without removing the directories.
+SUPPORTED_SDF_VERSIONS = ['1.9', '1.8', '1.7', '1.6', '1.5', '1.4', '1.3', '1.2']
+
+# The list of supported SDF conversions. This list includes versions that
+# a user can convert an existing SDF version to.
+SUPPORTED_SDF_CONVERSIONS = ['1.9', '1.8', '1.7', '1.6', '1.5', '1.4', '1.3']
+
+# whitespace indentation for C++ code
+INDENTATION = '  '
+
+
+def get_copyright_notice() -> str:
+    """
+    Provides the copyrigt notice for the C++ file
+
+    :returns: copyright notice
+    """
+    res = []
+    res.append('/*')
+    res.append(' * Copyright 2022 Open Source Robotics Foundation')
+    res.append(' *')
+    res.append(' * Licensed under the Apache License, Version 2.0 (the "License");')
+    res.append(' * you may not use this file except in compliance with the License.')
+    res.append(' * You may obtain a copy of the License at')
+    res.append(' *')
+    res.append(' *     http://www.apache.org/licenses/LICENSE-2.0')
+    res.append(' *')
+    res.append(' * Unless required by applicable law or agreed to in writing, software')
+    res.append(' * distributed under the License is distributed on an "AS IS" BASIS,')
+    res.append(' * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.')
+    res.append(' * See the License for the specific language governing permissions and')
+    res.append(' * limitations under the License.')
+    res.append(' *')
+    res.append('*/')
+    res.append('')
+    return '\n'.join(res)
+
+
+def get_file_header_prolog() -> str:
+    """
+    Provides the include statement, namespace and variable declaration of the C++ file
+
+    :returns: prolog of the C++ file
+    """
+    res = []
+    res.append('#include "EmbeddedSdf.hh"')
+    res.append('')
+    res.append('namespace sdf')
+    res.append('{')
+    res.append('inline namespace SDF_VERSION_NAMESPACE')
+    res.append('{')
+    res.append('/////////////////////////////////////////////////')
+    res.append('const std::map<std::string, std::string> &GetEmbeddedSdf()')
+    res.append('{')
+    res.append(INDENTATION + 'static const std::map<std::string, std::string> result {')
+    res.append('')
+    return '\n'.join(res)
+
+
+def embed_sdf_content(arg_path: str, arg_file_content: str) -> str:
+    """
+    Generates a string pair with the folder and filename as well as the content of the file
+
+    :param arg_path: Foldername and filename of the SDF
+    :param arg_file_content: Content of the provided file
+    :returns: raw string literal mapping pair for the std::map
+    """
+    res = []
+    res.append('// NOLINT')
+    res.append('{')
+    res.append(f'"{arg_path}",')
+    res.append('R"__sdf_literal__(')
+    res.append(f'{arg_file_content}')
+    res.append(')__sdf_literal__"')
+    res.append('},')
+    res.append('')
+    return '\n'.join(res)
+
+
+def get_map_content(arg_pathlist: Path) -> str:
+    """
+    Generates a string pair with the folder and filename as well as the content
+    of the file in ascending order
+
+    :param arg_pathlist: Foldername and all filenames inside it
+    :returns: mapping pairs for the std::map
+    """
+    map_str = ''
+    files = []
+    for path in pathlist:
+        files.append(str(path))
+    # get ascending order
+    files.sort()
+    for file in files:
+        with Path(file).open() as f:
+            content = f.read()
+            map_str += embed_sdf_content(file, content)
+    return map_str
+
+
+def get_file_header_epilog() -> str:
+    """
+    Provides the return statement and the closing brackets of the C++ file
+
+    :returns: epilog of the C++ file
+    """
+    res = []
+    res.append('')
+    res.append(INDENTATION + '};')
+    res.append('')
+    res.append(INDENTATION + 'return result;')
+    res.append('}')
+    res.append('')
+    res.append('}')
+    res.append('}  // namespace sdf')
+    res.append('')
+    return '\n'.join(res)
+
+
+if __name__ == "__main__":
+    copyright = get_copyright_notice()
+    prolog = get_file_header_prolog()
+
+    map_str = ""
+    for sdf_version in SUPPORTED_SDF_VERSIONS:
+        pathlist = Path(sdf_version).glob('*.sdf')
+        map_str += get_map_content(pathlist)
+
+    for sdf_conversion in SUPPORTED_SDF_CONVERSIONS:
+        pathlist = Path(sdf_conversion).glob('*.convert')
+        map_str += get_map_content(pathlist)
+
+    # remove the last comma
+    map_str = map_str[:-2]
+
+    epilog = get_file_header_epilog()
+
+    output = copyright + prolog + map_str + epilog
+
+    # output to stdin so that CMake can read it and create the appropriate file
+    print(output)