src/vpp-api/vapi/vapi_json_parser.py

   1 #!/usr/bin/env python2
   2
   3 import json
   4
   5
   6 class ParseError (Exception):
   7     pass
   8
   9
  10 magic_prefix = "vl_api_"
  11 magic_suffix = "_t"
  12
  13
  14 def remove_magic(what):
  15     if what.startswith(magic_prefix) and what.endswith(magic_suffix):
  16         return what[len(magic_prefix): - len(magic_suffix)]
  17     return what
  18
  19
  20 class Field(object):
  21
  22     def __init__(self, field_name, field_type, array_len=None,
  23                  nelem_field=None):
  24         self.name = field_name
  25         self.type = field_type
  26         self.len = array_len
  27         self.nelem_field = nelem_field
  28
  29     def __str__(self):
  30         if self.len is None:
  31             return "Field(name: %s, type: %s)" % (self.name, self.type)
  32         elif self.len > 0:
  33             return "Field(name: %s, type: %s, length: %s)" % (self.name,
  34                                                               self.type,
  35                                                               self.len)
  36         else:
  37             return (
  38                 "Field(name: %s, type: %s, variable length stored in: %s)" %
  39                 (self.name, self.type, self.nelem_field))
  40
  41     def is_vla(self):
  42         return self.nelem_field is not None
  43
  44     def has_vla(self):
  45         return self.is_vla() or self.type.has_vla()
  46
  47
  48 class Alias(Field):
  49     pass
  50
  51
  52 class Type(object):
  53     def __init__(self, name):
  54         self.name = name
  55
  56     def __str__(self):
  57         return self.name
  58
  59
  60 class SimpleType (Type):
  61
  62     def has_vla(self):
  63         return False
  64
  65
  66 def get_msg_header_defs(struct_type_class, field_class, json_parser, logger):
  67     return [
  68         struct_type_class(['msg_header1_t',
  69                            ['u16', '_vl_msg_id'],
  70                            ['u32', 'context'],
  71                            ],
  72                           json_parser, field_class, logger
  73                           ),
  74         struct_type_class(['msg_header2_t',
  75                            ['u16', '_vl_msg_id'],
  76                            ['u32', 'client_index'],
  77                            ['u32', 'context'],
  78                            ],
  79                           json_parser, field_class, logger
  80                           ),
  81     ]
  82
  83
  84 class Struct(object):
  85
  86     def __init__(self, name, fields):
  87         self.name = name
  88         self.fields = fields
  89         self.field_names = [n.name for n in self.fields]
  90         self.depends = [f.type for f in self.fields]
  91
  92     def __str__(self):
  93         return "[%s]" % "], [".join([str(f) for f in self.fields])
  94
  95     def has_vla(self):
  96         for f in self.fields:
  97             if f.has_vla():
  98                 return True
  99         return False
 100
 101
 102 class Enum(SimpleType):
 103     def __init__(self, name, value_pairs, enumtype):
 104         super(Enum, self).__init__(name)
 105         self.type = enumtype
 106         self.value_pairs = value_pairs
 107
 108     def __str__(self):
 109         return "Enum(%s, [%s])" % (
 110             self.name,
 111             "], [" .join(["%s => %s" % (i, j) for i, j in self.value_pairs])
 112         )
 113
 114
 115 class Union(Type):
 116     def __init__(self, name, type_pairs, crc):
 117         Type.__init__(self, name)
 118         self.crc = crc
 119         self.type_pairs = type_pairs
 120         self.depends = [t for t, _ in self.type_pairs]
 121
 122     def __str__(self):
 123         return "Union(%s, [%s])" % (
 124             self.name,
 125             "], [" .join(["%s %s" % (i, j) for i, j in self.type_pairs])
 126         )
 127
 128     def has_vla(self):
 129         return False
 130
 131
 132 class Message(object):
 133
 134     def __init__(self, logger, definition, json_parser):
 135         struct_type_class = json_parser.struct_type_class
 136         field_class = json_parser.field_class
 137         self.request = None
 138         self.logger = logger
 139         m = definition
 140         logger.debug("Parsing message definition `%s'" % m)
 141         name = m[0]
 142         self.name = name
 143         logger.debug("Message name is `%s'" % name)
 144         ignore = True
 145         self.header = None
 146         self.is_reply = json_parser.is_reply(self.name)
 147         self.is_event = json_parser.is_event(self.name)
 148         fields = []
 149         for header in get_msg_header_defs(struct_type_class, field_class,
 150                                           json_parser, logger):
 151             logger.debug("Probing header `%s'" % header.name)
 152             if header.is_part_of_def(m[1:]):
 153                 self.header = header
 154                 logger.debug("Found header `%s'" % header.name)
 155                 fields.append(field_class(field_name='header',
 156                                           field_type=self.header))
 157                 ignore = False
 158                 break
 159         if ignore and not self.is_event and not self.is_reply:
 160             raise ParseError("While parsing message `%s': could not find all "
 161                              "common header fields" % name)
 162         for field in m[1:]:
 163             if len(field) == 1 and 'crc' in field:
 164                 self.crc = field['crc']
 165                 logger.debug("Found CRC `%s'" % self.crc)
 166                 continue
 167             else:
 168                 field_type = json_parser.lookup_type_like_id(field[0])
 169                 logger.debug("Parsing message field `%s'" % field)
 170                 l = len(field)
 171                 if any(type(n) is dict for n in field):
 172                     l -= 1
 173                 if l == 2:
 174                     if self.header is not None and\
 175                             self.header.has_field(field[1]):
 176                         continue
 177                     p = field_class(field_name=field[1],
 178                                     field_type=field_type)
 179                 elif l == 3:
 180                     if field[2] == 0 and field[0] != 'string':
 181                         raise ParseError(
 182                             "While parsing message `%s': variable length "
 183                             "array `%s' doesn't have reference to member "
 184                             "containing the actual length" % (
 185                                 name, field[1]))
 186                     if field[0] == 'string' and field[2] > 0:
 187                         field_type = json_parser.lookup_type_like_id('u8')
 188
 189                     p = field_class(
 190                         field_name=field[1],
 191                         field_type=field_type,
 192                         array_len=field[2])
 193                 elif l == 4:
 194                     nelem_field = None
 195                     for f in fields:
 196                         if f.name == field[3]:
 197                             nelem_field = f
 198                     if nelem_field is None:
 199                         raise ParseError(
 200                             "While parsing message `%s': couldn't find "
 201                             "variable length array `%s' member containing "
 202                             "the actual length `%s'" % (
 203                                 name, field[1], field[3]))
 204                     p = field_class(
 205                         field_name=field[1],
 206                         field_type=field_type,
 207                         array_len=field[2],
 208                         nelem_field=nelem_field)
 209                 else:
 210                     raise Exception("Don't know how to parse message "
 211                                     "definition for message `%s': `%s'" %
 212                                     (m, m[1:]))
 213                 logger.debug("Parsed field `%s'" % p)
 214                 fields.append(p)
 215         self.fields = fields
 216         self.depends = [f.type for f in self.fields]
 217         logger.debug("Parsed message: %s" % self)
 218
 219     def __str__(self):
 220         return "Message(%s, [%s], {crc: %s}" % \
 221             (self.name,
 222              "], [".join([str(f) for f in self.fields]),
 223              self.crc)
 224
 225
 226 class StructType (Type, Struct):
 227
 228     def __init__(self, definition, json_parser, field_class, logger):
 229         t = definition
 230         logger.debug("Parsing struct definition `%s'" % t)
 231         name = t[0]
 232         fields = []
 233         for field in t[1:]:
 234             if len(field) == 1 and 'crc' in field:
 235                 self.crc = field['crc']
 236                 continue
 237             field_type = json_parser.lookup_type_like_id(field[0])
 238             logger.debug("Parsing type field `%s'" % field)
 239             if len(field) == 2:
 240                 p = field_class(field_name=field[1],
 241                                 field_type=field_type)
 242             elif len(field) == 3:
 243                 if field[2] == 0:
 244                     raise ParseError("While parsing type `%s': array `%s' has "
 245                                      "variable length" % (name, field[1]))
 246                 p = field_class(field_name=field[1],
 247                                 field_type=field_type,
 248                                 array_len=field[2])
 249             elif len(field) == 4:
 250                 nelem_field = None
 251                 for f in fields:
 252                     if f.name == field[3]:
 253                         nelem_field = f
 254                 if nelem_field is None:
 255                     raise ParseError(
 256                         "While parsing message `%s': couldn't find "
 257                         "variable length array `%s' member containing "
 258                         "the actual length `%s'" % (
 259                             name, field[1], field[3]))
 260                 p = field_class(field_name=field[1],
 261                                 field_type=field_type,
 262                                 array_len=field[2],
 263                                 nelem_field=nelem_field)
 264             else:
 265                 raise ParseError(
 266                     "Don't know how to parse field `%s' of type definition "
 267                     "for type `%s'" % (field, t))
 268             fields.append(p)
 269         Type.__init__(self, name)
 270         Struct.__init__(self, name, fields)
 271
 272     def __str__(self):
 273         return "StructType(%s, %s)" % (Type.__str__(self),
 274                                        Struct.__str__(self))
 275
 276     def has_field(self, name):
 277         return name in self.field_names
 278
 279     def is_part_of_def(self, definition):
 280         for idx in range(len(self.fields)):
 281             field = definition[idx]
 282             p = self.fields[idx]
 283             if field[1] != p.name:
 284                 return False
 285             if field[0] != p.type.name:
 286                 raise ParseError(
 287                     "Unexpected field type `%s' (should be `%s'), "
 288                     "while parsing msg/def/field `%s/%s/%s'" %
 289                     (field[0], p.type, p.name, definition, field))
 290         return True
 291
 292
 293 class JsonParser(object):
 294     def __init__(self, logger, files, simple_type_class=SimpleType,
 295                  enum_class=Enum, union_class=Union,
 296                  struct_type_class=StructType, field_class=Field,
 297                  message_class=Message, alias_class=Alias):
 298         self.services = {}
 299         self.messages = {}
 300         self.enums = {}
 301         self.unions = {}
 302         self.aliases = {}
 303         self.types = {
 304             x: simple_type_class(x) for x in [
 305                 'i8', 'i16', 'i32', 'i64',
 306                 'u8', 'u16', 'u32', 'u64',
 307                 'f64', 'bool'
 308             ]
 309         }
 310
 311         self.types['string'] = simple_type_class('vl_api_string_t')
 312         self.replies = set()
 313         self.events = set()
 314         self.simple_type_class = simple_type_class
 315         self.enum_class = enum_class
 316         self.union_class = union_class
 317         self.struct_type_class = struct_type_class
 318         self.field_class = field_class
 319         self.alias_class = alias_class
 320         self.message_class = message_class
 321
 322         self.exceptions = []
 323         self.json_files = []
 324         self.types_by_json = {}
 325         self.enums_by_json = {}
 326         self.unions_by_json = {}
 327         self.aliases_by_json = {}
 328         self.messages_by_json = {}
 329         self.logger = logger
 330         for f in files:
 331             self.parse_json_file(f)
 332         self.finalize_parsing()
 333
 334     def parse_json_file(self, path):
 335         self.logger.info("Parsing json api file: `%s'" % path)
 336         self.json_files.append(path)
 337         self.types_by_json[path] = []
 338         self.enums_by_json[path] = []
 339         self.unions_by_json[path] = []
 340         self.aliases_by_json[path] = []
 341         self.messages_by_json[path] = {}
 342         with open(path) as f:
 343             j = json.load(f)
 344             for k in j['services']:
 345                 if k in self.services:
 346                     raise ParseError("Duplicate service `%s'" % k)
 347                 self.services[k] = j['services'][k]
 348                 self.replies.add(self.services[k]["reply"])
 349                 if "events" in self.services[k]:
 350                     for x in self.services[k]["events"]:
 351                         self.events.add(x)
 352             for e in j['enums']:
 353                 name = e[0]
 354                 value_pairs = e[1:-1]
 355                 enumtype = self.types[e[-1]["enumtype"]]
 356                 enum = self.enum_class(name, value_pairs, enumtype)
 357                 self.enums[enum.name] = enum
 358                 self.logger.debug("Parsed enum: %s" % enum)
 359                 self.enums_by_json[path].append(enum)
 360             exceptions = []
 361             progress = 0
 362             last_progress = 0
 363             while True:
 364                 for u in j['unions']:
 365                     name = u[0]
 366                     if name in self.unions:
 367                         progress = progress + 1
 368                         continue
 369                     try:
 370                         type_pairs = [[self.lookup_type_like_id(t), n]
 371                                       for t, n in u[1:]]
 372                         union = self.union_class(name, type_pairs, 0)
 373                         progress = progress + 1
 374                     except ParseError as e:
 375                         exceptions.append(e)
 376                         continue
 377                     self.unions[union.name] = union
 378                     self.logger.debug("Parsed union: %s" % union)
 379                     self.unions_by_json[path].append(union)
 380                 for t in j['types']:
 381                     if t[0] in self.types:
 382                         progress = progress + 1
 383                         continue
 384                     try:
 385                         type_ = self.struct_type_class(t, self,
 386                                                        self.field_class,
 387                                                        self.logger)
 388                         if type_.name in self.types:
 389                             raise ParseError(
 390                                 "Duplicate type `%s'" % type_.name)
 391                         progress = progress + 1
 392                     except ParseError as e:
 393                         exceptions.append(e)
 394                         continue
 395                     self.types[type_.name] = type_
 396                     self.types_by_json[path].append(type_)
 397                     self.logger.debug("Parsed type: %s" % type_)
 398                 for name, body in j['aliases'].iteritems():
 399                     if name in self.aliases:
 400                         progress = progress + 1
 401                         continue
 402                     if 'length' in body:
 403                         array_len = body['length']
 404                     else:
 405                         array_len = None
 406                     try:
 407                         t = self.lookup_type_like_id(body['type'])
 408                     except ParseError as e:
 409                         exceptions.append(e)
 410                         continue
 411                     alias = self.alias_class(name, t, array_len)
 412                     self.aliases[name] = alias
 413                     self.logger.debug("Parsed alias: %s" % alias)
 414                     self.aliases_by_json[path].append(alias)
 415                 if not exceptions:
 416                     # finished parsing
 417                     break
 418                 if progress <= last_progress:
 419                     # cannot make forward progress
 420                     self.exceptions.extend(exceptions)
 421                     break
 422                 exceptions = []
 423                 last_progress = progress
 424                 progress = 0
 425             prev_length = len(self.messages)
 426             processed = []
 427             while True:
 428                 exceptions = []
 429                 for m in j['messages']:
 430                     if m in processed:
 431                         continue
 432                     try:
 433                         msg = self.message_class(self.logger, m, self)
 434                         if msg.name in self.messages:
 435                             raise ParseError(
 436                                 "Duplicate message `%s'" % msg.name)
 437                     except ParseError as e:
 438                         exceptions.append(e)
 439                         continue
 440                     self.messages[msg.name] = msg
 441                     self.messages_by_json[path][msg.name] = msg
 442                     processed.append(m)
 443                 if prev_length == len(self.messages):
 444                     # cannot make forward progress ...
 445                     self.exceptions.extend(exceptions)
 446                     break
 447                 prev_length = len(self.messages)
 448
 449     def lookup_type_like_id(self, name):
 450         mundane_name = remove_magic(name)
 451         if name in self.types:
 452             return self.types[name]
 453         elif name in self.enums:
 454             return self.enums[name]
 455         elif name in self.unions:
 456             return self.unions[name]
 457         elif name in self.aliases:
 458             return self.aliases[name]
 459         elif mundane_name in self.types:
 460             return self.types[mundane_name]
 461         elif mundane_name in self.enums:
 462             return self.enums[mundane_name]
 463         elif mundane_name in self.unions:
 464             return self.unions[mundane_name]
 465         elif mundane_name in self.aliases:
 466             return self.aliases[mundane_name]
 467         raise ParseError(
 468             "Could not find type, enum or union by magic name `%s' nor by "
 469             "mundane name `%s'" % (name, mundane_name))
 470
 471     def is_reply(self, message):
 472         return message in self.replies
 473
 474     def is_event(self, message):
 475         return message in self.events
 476
 477     def get_reply(self, message):
 478         return self.messages[self.services[message]['reply']]
 479
 480     def finalize_parsing(self):
 481         if len(self.messages) == 0:
 482             for e in self.exceptions:
 483                 self.logger.warning(e)
 484         for jn, j in self.messages_by_json.items():
 485             remove = []
 486             for n, m in j.items():
 487                 try:
 488                     if not m.is_reply and not m.is_event:
 489                         try:
 490                             m.reply = self.get_reply(n)
 491                             if "stream" in self.services[m.name]:
 492                                 m.reply_is_stream = \
 493                                     self.services[m.name]["stream"]
 494                             else:
 495                                 m.reply_is_stream = False
 496                             m.reply.request = m
 497                         except:
 498                             raise ParseError(
 499                                 "Cannot find reply to message `%s'" % n)
 500                 except ParseError as e:
 501                     self.exceptions.append(e)
 502                     remove.append(n)
 503
 504             self.messages_by_json[jn] = {
 505                 k: v for k, v in j.items() if k not in remove}