sync/protocol/prepare_protos_for_java_tests.py

   1 #!/usr/bin/env python
   2 # Copyright 2015 The Chromium Authors. All rights reserved.
   3 # Use of this source code is governed by a BSD-style license that can be
   4 # found in the LICENSE file.
   5
   6 """Converts protocol buffer definitions to ones supported by the Nano library.
   7
   8 Note: Java files generated from the output of this script should only be used
   9 in tests.
  10
  11 Chromium uses the Java Protocol Buffers Nano runtime library. This library,
  12 compared to the standard proto compilter in C++, is limited. Most notably, the
  13 retain_unknown_fields option is not supported.
  14
  15 This script also adds Java-specific configs to enable usage in Java. This script
  16 is Sync-specific, so a Sync package name is used.
  17 """
  18
  19 import optparse
  20 import os
  21 import re
  22 import sys
  23
  24
  25 def main():
  26   parser = optparse.OptionParser(
  27       usage='Usage: %prog [options...] original_proto_files')
  28   parser.add_option('-o', '--output_dir', dest='output_dir',
  29                     help='Where to put the modified proto files')
  30
  31   options, args = parser.parse_args()
  32   if not options.output_dir:
  33     print 'output_dir not specified.'
  34     return 1
  35
  36   # Map of original base file names to their contents.
  37   original_proto_contents = {}
  38   for original_proto_file in args:
  39     with open(original_proto_file, 'r') as original_file:
  40       base_name = os.path.basename(original_proto_file)
  41       original_proto_contents[base_name] = original_file.read()
  42
  43   for file_name, original_contents in original_proto_contents.iteritems():
  44     new_contents = ConvertProtoFileContents(original_contents)
  45     with open(os.path.join(options.output_dir, file_name), 'w') as new_file:
  46       new_file.write(new_contents)
  47
  48
  49 def ConvertProtoFileContents(contents):
  50   """Returns a Nano-compatible version of contents.
  51
  52   Args:
  53     contents: The contents of a protocol buffer definition file.
  54   """
  55   # Remove the retain_unknown_fields option.
  56   incompatible_option_regex = re.compile(
  57       r'^\s*option\s+retain_unknown_fields\s*=.*;', re.MULTILINE)
  58   pruned_contents = incompatible_option_regex.sub('', contents)
  59
  60   # Add the java_multiple_files and java_package options. Options must be set
  61   # after the syntax declaration, so look for the declaration and place the
  62   # options immediately after it.
  63   # TODO(pvalenzuela): Set Java options via proto compiler flags instead of
  64   # modifying the files here.
  65   syntax_regex = re.compile(r'^\s*syntax\s*=.*;', re.MULTILINE)
  66   syntax_end = syntax_regex.search(pruned_contents).end()
  67   java_options = ('option java_multiple_files = true; '
  68                   'option java_package = "org.chromium.sync.protocol";')
  69
  70   contents_to_join = (pruned_contents[:syntax_end], java_options,
  71                       pruned_contents[syntax_end:])
  72   return ''.join(contents_to_join)
  73
  74
  75 if __name__ == '__main__':
  76   sys.exit(main())