gen_encoding_templates.py

#!/usr/bin/env python

# Copyright 2019 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""
This is a very simple script to generate lib/encoding_cc.template
and lib/encoding_h.template from the C++ files in the encoding directory.
This lets us edit the .cc / .h files, which is more pleasant
(there are tests after all), and then update the templates
mechanically.
TODO(johannes): Migrate toward directly depending on encoding/encoding.{h,cc} to
obviate the need for generating a copy in lib/encoding_{h,cc}.template.
"""

def ReadBody(filename, system_includes, bodies):
  inside_namespace = False
  body = ['\n', '// ===== %s =====\n' % filename, '\n']
  for line in open(filename):
    if line == 'namespace inspector_protocol_encoding {\n':
      inside_namespace = True
      continue
    if line == '}  // namespace inspector_protocol_encoding\n':
      inside_namespace = False
      continue
    if line.startswith('#include <'):
      system_includes.append(line)
    if inside_namespace:
      body.append(line)
  bodies.append(''.join(body))

LICENSE = """
// Copyright 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
"""

NAMESPACE_START = """
{% for namespace in config.protocol.namespace %}
namespace {{namespace}} {
{% endfor %}
"""

NAMESPACE_END = """
{% for namespace in config.protocol.namespace %}
} // namespace {{namespace}}
{% endfor %}
"""

def GenTemplate(with_header_guard, filename, from_cpp_files):
  contents = [
      '{# This template is generated by gen_cbor_templates.py. #}\n',
      '// Generated by %s.\n' % filename,
      LICENSE,
      '\n']
  contents.append('{% if config.encoding_lib.header == "" %}\n')
  if with_header_guard:
    contents.append('#ifndef {{"_".join(config.protocol.namespace)}}_%s_h\n' % with_header_guard)
    contents.append('#define {{"_".join(config.protocol.namespace)}}_%s_h\n' % with_header_guard)
  system_includes=[]
  bodies=[]
  for cpp_file in from_cpp_files:
    ReadBody(cpp_file, system_includes, bodies)
  system_includes = list(set(system_includes))  # unique
  system_includes.sort()
  contents.append('\n')
  contents += system_includes
  contents.append(NAMESPACE_START)
  contents += bodies
  contents.append(NAMESPACE_END)
  if with_header_guard:
    contents.append('#endif // !defined({{"_".join(config.protocol.namespace)}}_%s_h)' % with_header_guard)
  contents.append('\n')
  contents.append('{% endif %}\n')

  open(filename, 'w').write(''.join(contents))

if __name__ == '__main__':
  GenTemplate(with_header_guard=None, filename='lib/encoding_cpp.template',
              from_cpp_files=['encoding/encoding.cc'])
  GenTemplate(with_header_guard='encoding', filename='lib/encoding_h.template',
              from_cpp_files=['encoding/encoding.h'])