261 

   262 

   263 def parselist(value):

   264     """parse a configuration value as a list of comma/space separated strings

   265 

   266     >>> parselist(b'this,is "a small" ,test')

   267     ['this', 'is', 'a small', 'test']

   268     """

   269 

   270     def _parse_plain(parts, s, offset):

   271         whitespace = False

   272         while offset < len(s) and (

   273             s[offset : offset + 1].isspace() or s[offset : offset + 1] == b','

   274         ):

   275             whitespace = True

   276             offset += 1

   277         if offset >= len(s):

   278             return None, parts, offset

   279         if whitespace:

   280             parts.append(b'')

   281         if s[offset : offset + 1] == b'"' and not parts[-1]:

   282             return _parse_quote, parts, offset + 1

   283         elif s[offset : offset + 1] == b'"' and parts[-1][-1:] == b'\\':

   284             parts[-1] = parts[-1][:-1] + s[offset : offset + 1]

   285             return _parse_plain, parts, offset + 1

   286         parts[-1] += s[offset : offset + 1]

   287         return _parse_plain, parts, offset + 1

   288 

   289     def _parse_quote(parts, s, offset):

   290         if offset < len(s) and s[offset : offset + 1] == b'"':  # ""

   291             parts.append(b'')

   292             offset += 1

   293             while offset < len(s) and (

   294                 s[offset : offset + 1].isspace()

   295                 or s[offset : offset + 1] == b','

   296             ):

   297                 offset += 1

   298             return _parse_plain, parts, offset

   299 

   300         while offset < len(s) and s[offset : offset + 1] != b'"':

   301             if (

   302                 s[offset : offset + 1] == b'\\'

   303                 and offset + 1 < len(s)

   304                 and s[offset + 1 : offset + 2] == b'"'

   305             ):

   306                 offset += 1

   307                 parts[-1] += b'"'

   308             else:

   309                 parts[-1] += s[offset : offset + 1]

   310             offset += 1

   311 

   312         if offset >= len(s):

   313             real_parts = _configlist(parts[-1])

   314             if not real_parts:

   315                 parts[-1] = b'"'

   316             else:

   317                 real_parts[0] = b'"' + real_parts[0]

   318                 parts = parts[:-1]

   319                 parts.extend(real_parts)

   320             return None, parts, offset

   321 

   322         offset += 1

   323         while offset < len(s) and s[offset : offset + 1] in [b' ', b',']:

   324             offset += 1

   325 

   326         if offset < len(s):

   327             if offset + 1 == len(s) and s[offset : offset + 1] == b'"':

   328                 parts[-1] += b'"'

   329                 offset += 1

   330             else:

   331                 parts.append(b'')

   332         else:

   333             return None, parts, offset

   334 

   335         return _parse_plain, parts, offset

   336 

   337     def _configlist(s):

   338         s = s.rstrip(b' ,')

   339         if not s:

   340             return []

   341         parser, parts, offset = _parse_plain, [b''], 0

   342         while parser:

   343             parser, parts, offset = parser(parts, s, offset)

   344         return parts

   345 

   346     if value is not None and isinstance(value, bytes):

   347         result = _configlist(value.lstrip(b' ,\n'))

   348     else:

   349         result = value

   350     return result or []