#!/usr/bin/env python
# Copyright (C) 2019 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# This tool checks for layering violations in the include/ directory.
# It checks that:
# - public includes don't end up depending on non-public /ext/ includes.
# - public includes don't end up depending on private src/ headers.
# - We use consistently <angle brackets> for other libraries.

import os
import re
import subprocess
import sys

ROOT_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))


def main():
  errors = 0
  include_root = os.path.join(ROOT_DIR, 'include')
  for root, _, files in os.walk(include_root):
    for fname in files:
      fpath = os.path.join(root, fname)
      rel_path = os.path.relpath(fpath, ROOT_DIR)
      if not os.path.isfile(fpath):
        continue
      if fpath.endswith('.cc'):
        sys.stderr.write(
            '.cc files not allowed in includes/ : ' + rel_path + '\n')
        errors += 1
        continue
      if fpath.endswith('.h'):
        with open(fpath) as f:
          lines = f.readlines()
        for line in lines:
          m = re.findall(r'^#include "(.*\.h)"', line)
          if not m:
            continue
          incl = m[0]

          # Allow only #include "perfetto/..." and not "src/..." from include/.
          if not incl.startswith('perfetto/'):
            sys.stderr.write(
                ('Public header %s is trying to include %s which is outside ' +
                 'of include/. If you are trying to include a library use ' +
                 ' <angle brackets> instead\n') % (rel_path, incl))
            errors += 1
            continue

          # Ignore lines marked with nogncheck.
          if '// nogncheck' in line:
            continue

          # Public (non-/ext/) headers cannot include /ext/ headers.
          if (not rel_path.startswith('include/perfetto/ext/') and
                  incl.startswith('perfetto/ext/')):
            sys.stderr.write(('Public header %s cannot include the non-public' +
                              '/ext/ header %s.\n') % (rel_path, incl))
            errors += 1
            continue

  return 0 if errors == 0 else 1


if __name__ == '__main__':
  sys.exit(main())