Guess source tree root from common file prefix.

      i['compiled_patterns'].append(re.compile(pat))

def find_android_root(path):

def find_warn_py_and_android_root(path):

  """Set and return android_root path if it is found."""

  global android_root

  parts = path.split('/')

    # Android root directory should contain this script.

    if os.path.exists(root_path + '/build/make/tools/warn.py'):

      android_root = root_path

      return root_path

  return ''

      return True

  return False

def find_android_root():

  """Guess android_root from common prefix of file paths."""

  # Use the longest common prefix of the absolute file paths

  # of the first 10000 warning messages as the android_root.

  global android_root

  warning_lines = set()

  warning_pattern = re.compile('^/[^ ]*/[^ ]*: warning: .*')

  count = 0

  infile = io.open(args.buildlog, mode='r', encoding='utf-8')

  for line in infile:

    if warning_pattern.match(line):

      warning_lines.add(line)

      count += 1

      if count > 9999:

        break

      # Try to find warn.py and use its location to find

      # the source tree root.

      if count < 100:

        path = os.path.normpath(re.sub(':.*$', '', line))

        if find_warn_py_and_android_root(path):

          return

  # Do not use common prefix of a small number of paths.

  if count > 10:

    root_path = os.path.commonprefix(warning_lines)

    if len(root_path) > 2 and root_path[len(root_path) - 1] == '/':

      android_root = root_path[:-1]

def remove_android_root_prefix(path):

  """Normalize file path relative to android_root."""

  # If path is not an absolute path, just normalize it.

  path = os.path.normpath(path)

  if path[0] != '/':

    return path

  # Remove known prefix of root path and normalize the suffix.

  if android_root or find_android_root(path):

  if path[0] == '/' and android_root:

    return remove_android_root_prefix(path)

  else:

  return path

def main():

  find_android_root()

  # We must use 'utf-8' codec to parse some non-ASCII code in warnings.

  warning_lines = parse_input_file(

      io.open(args.buildlog, mode='r', encoding='utf-8'))