Add a script to check OWNERS file syntax.

#!/usr/bin/python

"""Parse and check syntax errors of a given OWNERS file."""

import argparse

import re

import sys

import urllib2

parser = argparse.ArgumentParser(description='Check OWNERS file syntax')

parser.add_argument('-v', '--verbose', dest='verbose',

                    action='store_true', default=False,

                    help='Verbose output to debug')

parser.add_argument('-c', '--check_address', dest='check_address',

                    action='store_true', default=False,

                    help='Check email addresses')

parser.add_argument(dest='owners', metavar='OWNERS', nargs='+',

                    help='Path to OWNERS file')

args = parser.parse_args()

gerrit_server = 'https://android-review.googlesource.com'

checked_addresses = {}

def echo(msg):

  if args.verbose:

    print msg

def find_address(address):

  if address not in checked_addresses:

    request = gerrit_server + '/accounts/?suggest&q=' + address

    echo('Checking email address: ' + address)

    result = urllib2.urlopen(request).read()

    expected = '"email": "' + address + '"'

    checked_addresses[address] = (result.find(expected) >= 0)

  return checked_addresses[address]

def main():

  # One regular expression to check all valid lines.

  noparent = 'set +noparent'

  email = '([^@ ]+@[^ @]+|\\*)'

  directive = '(%s|%s)' % (email, noparent)

  glob = '[a-zA-Z0-9_\\.\\-\\*\\?]+'

  perfile = 'per-file +' + glob + ' *= *' + directive

  pats = '(|%s|%s|%s)$' % (noparent, email, perfile)

  patterns = re.compile(pats)

  # One pattern to capture email address.

  email_address = '.*(@| |=|^)([^@ =]+@[^ @]+)'

  address_pattern = re.compile(email_address)

  error = 0

  for fname in args.owners:

    echo('Checking file: ' + fname)

    num = 0

    for line in open(fname, 'r'):

      num += 1

      stripped_line = re.sub('#.*$', '', line).strip()

      if not patterns.match(stripped_line):

        error = 1

        print('%s:%d: ERROR: unknown line [%s]'

              % (fname, num, line.strip()))

      elif args.check_address and address_pattern.match(stripped_line):

        address = address_pattern.match(stripped_line).group(2)

        if find_address(address):

          echo('Found email address: ' + address)

        else:

          error = 1

          print('%s:%d: ERROR: unknown email address: %s'

                % (fname, num, address))

  sys.exit(error)

if __name__ == '__main__':

  main()