src/vpp-api/vapi/vapi_json_parser.py

   1 #!/usr/bin/env python3
   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     def __init__(self, field_name, field_type, array_len=None, nelem_field=None):
  22         self.name = field_name
  23         self.type = field_type
  24         self.len = array_len
  25         self.nelem_field = nelem_field
  26
  27     def __str__(self):
  28         if self.len is None:
  29             return "Field(name: %s, type: %s)" % (self.name, self.type)
  30         elif type(self.len) == dict:
  31             return "Field(name: %s, type: %s, length: %s)" % (
  32                 self.name,
  33                 self.type,
  34                 self.len,
  35             )
  36         elif self.len > 0:
  37             return "Field(name: %s, type: %s, length: %s)" % (
  38                 self.name,
  39                 self.type,
  40                 self.len,
  41             )
  42         else:
  43             return "Field(name: %s, type: %s, variable length stored in: %s)" % (
  44                 self.name,
  45                 self.type,
  46                 self.nelem_field,
  47             )
  48
  49     def is_vla(self):
  50         return self.nelem_field is not None
  51
  52     def has_vla(self):
  53         return self.is_vla() or self.type.has_vla()
  54
  55
  56 class Alias(Field):
  57     pass
  58
  59
  60 class Type(object):
  61     def __init__(self, name):
  62         self.name = name
  63
  64     def __str__(self):
  65         return self.name
  66
  67
  68 class SimpleType(Type):
  69     def has_vla(self):
  70         return False
  71
  72
  73 def get_msg_header_defs(struct_type_class, field_class, json_parser, logger):
  74     return [
  75         struct_type_class(
  76             [
  77                 "msg_header1_t",
  78                 ["u16", "_vl_msg_id"],
  79                 ["u32", "context"],
  80             ],
  81             json_parser,
  82             field_class,
  83             logger,
  84         ),
  85         struct_type_class(
  86             [
  87                 "msg_header2_t",
  88                 ["u16", "_vl_msg_id"],
  89                 ["u32", "client_index"],
  90                 ["u32", "context"],
  91             ],
  92             json_parser,
  93             field_class,
  94             logger,
  95         ),
  96     ]
  97
  98
  99 class Struct(object):
 100     def __init__(self, name, fields):
 101         self.name = name
 102         self.fields = fields
 103         self.field_names = [n.name for n in self.fields]
 104         self.depends = [f.type for f in self.fields]
 105
 106     def __str__(self):
 107         return "[%s]" % "], [".join([str(f) for f in self.fields])
 108
 109     def has_vla(self):
 110         for f in self.fields:
 111             if f.has_vla():
 112                 return True
 113         return False
 114
 115
 116 class Enum(SimpleType):
 117     def __init__(self, name, value_pairs, enumtype):
 118         super(Enum, self).__init__(name)
 119         self.type = enumtype
 120         self.value_pairs = value_pairs
 121
 122     def __str__(self):
 123         return "Enum(%s, [%s])" % (
 124             self.name,
 125             "], [".join(["%s => %s" % (i, j) for i, j in self.value_pairs]),
 126         )
 127
 128
 129 class Union(Type):
 130     def __init__(self, name, type_pairs, crc):
 131         Type.__init__(self, name)
 132         self.crc = crc
 133         self.type_pairs = type_pairs
 134         self.depends = [t for t, _ in self.type_pairs]
 135
 136     def __str__(self):
 137         return "Union(%s, [%s])" % (
 138             self.name,
 139             "], [".join(["%s %s" % (i, j) for i, j in self.type_pairs]),
 140         )
 141
 142     def has_vla(self):
 143         return False
 144
 145
 146 class Message(object):
 147     def __init__(self, logger, definition, json_parser):
 148         struct_type_class = json_parser.struct_type_class
 149         field_class = json_parser.field_class
 150         self.request = None
 151         self.logger = logger
 152         m = definition
 153         logger.debug("Parsing message definition `%s'" % m)
 154         name = m[0]
 155         self.name = name
 156         logger.debug("Message name is `%s'" % name)
 157         ignore = True
 158         self.header = None
 159         self.is_reply = json_parser.is_reply(self.name)
 160         self.is_event = json_parser.is_event(self.name)
 161         fields = []
 162         for header in get_msg_header_defs(
 163             struct_type_class, field_class, json_parser, logger
 164         ):
 165             logger.debug("Probing header `%s'" % header.name)
 166             if header.is_part_of_def(m[1:]):
 167                 self.header = header
 168                 logger.debug("Found header `%s'" % header.name)
 169                 fields.append(field_class(field_name="header", field_type=self.header))
 170                 ignore = False
 171                 break
 172         if ignore and not self.is_event and not self.is_reply:
 173             raise ParseError(
 174                 "While parsing message `%s': could not find all "
 175                 "common header fields" % name
 176             )
 177         for field in m[1:]:
 178             if isinstance(field, dict) and "crc" in field:
 179                 self.crc = field["crc"]
 180                 logger.debug("Found CRC `%s'" % self.crc)
 181                 continue
 182             else:
 183                 field_type = json_parser.lookup_type_like_id(field[0])
 184                 logger.debug("Parsing message field `%s'" % field)
 185                 l = len(field)
 186                 if any(type(n) is dict for n in field):
 187                     l -= 1
 188                 if l == 2:
 189                     if self.header is not None and self.header.has_field(field[1]):
 190                         continue
 191                     p = field_class(field_name=field[1], field_type=field_type)
 192                 elif l == 3:
 193                     if field[2] == 0 and field[0] != "string":
 194                         raise ParseError(
 195                             "While parsing message `%s': variable length "
 196                             "array `%s' doesn't have reference to member "
 197                             "containing the actual length" % (name, field[1])
 198                         )
 199                     if field[0] == "string" and field[2] > 0:
 200                         field_type = json_parser.lookup_type_like_id("u8")
 201
 202                     p = field_class(
 203                         field_name=field[1], field_type=field_type, array_len=field[2]
 204                     )
 205                 elif l == 4:
 206                     nelem_field = None
 207                     for f in fields:
 208                         if f.name == field[3]:
 209                             nelem_field = f
 210                     if nelem_field is None:
 211                         raise ParseError(
 212                             "While parsing message `%s': couldn't find "
 213                             "variable length array `%s' member containing "
 214                             "the actual length `%s'" % (name, field[1], field[3])
 215                         )
 216                     p = field_class(
 217                         field_name=field[1],
 218                         field_type=field_type,
 219                         array_len=field[2],
 220                         nelem_field=nelem_field,
 221                     )
 222                 else:
 223                     raise Exception(
 224                         "Don't know how to parse message "
 225                         "definition for message `%s': `%s'" % (m, m[1:])
 226                     )
 227                 logger.debug("Parsed field `%s'" % p)
 228                 fields.append(p)
 229         self.fields = fields
 230         self.depends = [f.type for f in self.fields]
 231         logger.debug("Parsed message: %s" % self)
 232
 233     def __str__(self):
 234         return "Message(%s, [%s], {crc: %s}" % (
 235             self.name,
 236             "], [".join([str(f) for f in self.fields]),
 237             self.crc,
 238         )
 239
 240
 241 class StructType(Type, Struct):
 242     def __init__(self, definition, json_parser, field_class, logger):
 243         t = definition
 244         logger.debug("Parsing struct definition `%s'" % t)
 245         name = t[0]
 246         fields = []
 247         for field in t[1:]:
 248             if len(field) == 1 and "crc" in field:
 249                 self.crc = field["crc"]
 250                 continue
 251             field_type = json_parser.lookup_type_like_id(field[0])
 252             logger.debug("Parsing type field `%s'" % field)
 253             if len(field) == 2:
 254                 p = field_class(field_name=field[1], field_type=field_type)
 255             elif len(field) == 3:
 256                 if field[2] == 0:
 257                     raise ParseError(
 258                         "While parsing type `%s': array `%s' has "
 259                         "variable length" % (name, field[1])
 260                     )
 261                 p = field_class(
 262                     field_name=field[1], field_type=field_type, array_len=field[2]
 263                 )
 264             elif len(field) == 4:
 265                 nelem_field = None
 266                 for f in fields:
 267                     if f.name == field[3]:
 268                         nelem_field = f
 269                 if nelem_field is None:
 270                     raise ParseError(
 271                         "While parsing message `%s': couldn't find "
 272                         "variable length array `%s' member containing "
 273                         "the actual length `%s'" % (name, field[1], field[3])
 274                     )
 275                 p = field_class(
 276                     field_name=field[1],
 277                     field_type=field_type,
 278                     array_len=field[2],
 279                     nelem_field=nelem_field,
 280                 )
 281             else:
 282                 raise ParseError(
 283                     "Don't know how to parse field `%s' of type definition "
 284                     "for type `%s'" % (field, t)
 285                 )
 286             fields.append(p)
 287         Type.__init__(self, name)
 288         Struct.__init__(self, name, fields)
 289
 290     def __str__(self):
 291         return "StructType(%s, %s)" % (Type.__str__(self), Struct.__str__(self))
 292
 293     def has_field(self, name):
 294         return name in self.field_names
 295
 296     def is_part_of_def(self, definition):
 297         for idx in range(len(self.fields)):
 298             field = definition[idx]
 299             p = self.fields[idx]
 300             if field[1] != p.name:
 301                 return False
 302             if field[0] != p.type.name:
 303                 raise ParseError(
 304                     "Unexpected field type `%s' (should be `%s'), "
 305                     "while parsing msg/def/field `%s/%s/%s'"
 306                     % (field[0], p.type, p.name, definition, field)
 307                 )
 308         return True
 309
 310
 311 class JsonParser(object):
 312     def __init__(
 313         self,
 314         logger,
 315         files,
 316         simple_type_class=SimpleType,
 317         enum_class=Enum,
 318         union_class=Union,
 319         struct_type_class=StructType,
 320         field_class=Field,
 321         message_class=Message,
 322         alias_class=Alias,
 323     ):
 324         self.services = {}
 325         self.messages = {}
 326         self.enums = {}
 327         self.unions = {}
 328         self.aliases = {}
 329         self.types = {
 330             x: simple_type_class(x)
 331             for x in [
 332                 "i8",
 333                 "i16",
 334                 "i32",
 335                 "i64",
 336                 "u8",
 337                 "u16",
 338                 "u32",
 339                 "u64",
 340                 "f64",
 341                 "bool",
 342             ]
 343         }
 344
 345         self.types["string"] = simple_type_class("vl_api_string_t")
 346         self.replies = set()
 347         self.events = set()
 348         self.simple_type_class = simple_type_class
 349         self.enum_class = enum_class
 350         self.union_class = union_class
 351         self.struct_type_class = struct_type_class
 352         self.field_class = field_class
 353         self.alias_class = alias_class
 354         self.message_class = message_class
 355
 356         self.exceptions = []
 357         self.json_files = []
 358         self.types_by_json = {}
 359         self.enums_by_json = {}
 360         self.unions_by_json = {}
 361         self.aliases_by_json = {}
 362         self.messages_by_json = {}
 363         self.logger = logger
 364         for f in files:
 365             self.parse_json_file(f)
 366         self.finalize_parsing()
 367
 368     def parse_json_file(self, path):
 369         self.logger.info("Parsing json api file: `%s'" % path)
 370         self.json_files.append(path)
 371         self.types_by_json[path] = []
 372         self.enums_by_json[path] = []
 373         self.unions_by_json[path] = []
 374         self.aliases_by_json[path] = []
 375         self.messages_by_json[path] = {}
 376         with open(path) as f:
 377             j = json.load(f)
 378             for k in j["services"]:
 379                 if k in self.services:
 380                     raise ParseError("Duplicate service `%s'" % k)
 381                 self.services[k] = j["services"][k]
 382                 self.replies.add(self.services[k]["reply"])
 383                 if "events" in self.services[k]:
 384                     for x in self.services[k]["events"]:
 385                         self.events.add(x)
 386             for e in j["enums"]:
 387                 name = e[0]
 388                 value_pairs = e[1:-1]
 389                 enumtype = self.types[e[-1]["enumtype"]]
 390                 enum = self.enum_class(name, value_pairs, enumtype)
 391                 self.enums[enum.name] = enum
 392                 self.logger.debug("Parsed enum: %s" % enum)
 393                 self.enums_by_json[path].append(enum)
 394             exceptions = []
 395             progress = 0
 396             last_progress = 0
 397             while True:
 398                 for u in j["unions"]:
 399                     name = u[0]
 400                     if name in self.unions:
 401                         progress = progress + 1
 402                         continue
 403                     try:
 404                         type_pairs = [
 405                             [self.lookup_type_like_id(t), n] for t, n in u[1:]
 406                         ]
 407                         union = self.union_class(name, type_pairs, 0)
 408                         progress = progress + 1
 409                     except ParseError as e:
 410                         exceptions.append(e)
 411                         continue
 412                     self.unions[union.name] = union
 413                     self.logger.debug("Parsed union: %s" % union)
 414                     self.unions_by_json[path].append(union)
 415                 for t in j["types"]:
 416                     if t[0] in self.types:
 417                         progress = progress + 1
 418                         continue
 419                     try:
 420                         type_ = self.struct_type_class(
 421                             t, self, self.field_class, self.logger
 422                         )
 423                         if type_.name in self.types:
 424                             raise ParseError("Duplicate type `%s'" % type_.name)
 425                         progress = progress + 1
 426                     except ParseError as e:
 427                         exceptions.append(e)
 428                         continue
 429                     self.types[type_.name] = type_
 430                     self.types_by_json[path].append(type_)
 431                     self.logger.debug("Parsed type: %s" % type_)
 432                 for name, body in j["aliases"].items():
 433                     if name in self.aliases:
 434                         progress = progress + 1
 435                         continue
 436                     if "length" in body:
 437                         array_len = body["length"]
 438                     else:
 439                         array_len = None
 440                     try:
 441                         t = self.lookup_type_like_id(body["type"])
 442                     except ParseError as e:
 443                         exceptions.append(e)
 444                         continue
 445                     alias = self.alias_class(name, t, array_len)
 446                     self.aliases[name] = alias
 447                     self.logger.debug("Parsed alias: %s" % alias)
 448                     self.aliases_by_json[path].append(alias)
 449                 if not exceptions:
 450                     # finished parsing
 451                     break
 452                 if progress <= last_progress:
 453                     # cannot make forward progress
 454                     self.exceptions.extend(exceptions)
 455                     break
 456                 exceptions = []
 457                 last_progress = progress
 458                 progress = 0
 459             prev_length = len(self.messages)
 460             processed = []
 461             while True:
 462                 exceptions = []
 463                 for m in j["messages"]:
 464                     if m in processed:
 465                         continue
 466                     try:
 467                         msg = self.message_class(self.logger, m, self)
 468                         if msg.name in self.messages:
 469                             raise ParseError("Duplicate message `%s'" % msg.name)
 470                     except ParseError as e:
 471                         exceptions.append(e)
 472                         continue
 473                     self.messages[msg.name] = msg
 474                     self.messages_by_json[path][msg.name] = msg
 475                     processed.append(m)
 476                 if prev_length == len(self.messages):
 477                     # cannot make forward progress ...
 478                     self.exceptions.extend(exceptions)
 479                     break
 480                 prev_length = len(self.messages)
 481
 482     def lookup_type_like_id(self, name):
 483         mundane_name = remove_magic(name)
 484         if name in self.types:
 485             return self.types[name]
 486         elif name in self.enums:
 487             return self.enums[name]
 488         elif name in self.unions:
 489             return self.unions[name]
 490         elif name in self.aliases:
 491             return self.aliases[name]
 492         elif mundane_name in self.types:
 493             return self.types[mundane_name]
 494         elif mundane_name in self.enums:
 495             return self.enums[mundane_name]
 496         elif mundane_name in self.unions:
 497             return self.unions[mundane_name]
 498         elif mundane_name in self.aliases:
 499             return self.aliases[mundane_name]
 500         raise ParseError(
 501             "Could not find type, enum or union by magic name `%s' nor by "
 502             "mundane name `%s'" % (name, mundane_name)
 503         )
 504
 505     def is_reply(self, message):
 506         return message in self.replies
 507
 508     def is_event(self, message):
 509         return message in self.events
 510
 511     def get_reply(self, message):
 512         return self.messages[self.services[message]["reply"]]
 513
 514     def finalize_parsing(self):
 515         if len(self.messages) == 0:
 516             for e in self.exceptions:
 517                 self.logger.warning(e)
 518         for jn, j in self.messages_by_json.items():
 519             remove = []
 520             for n, m in j.items():
 521                 try:
 522                     if not m.is_reply and not m.is_event:
 523                         try:
 524                             m.reply = self.get_reply(n)
 525                             if "stream" in self.services[m.name]:
 526                                 m.reply_is_stream = self.services[m.name]["stream"]
 527                             else:
 528                                 m.reply_is_stream = False
 529                             m.reply.request = m
 530                         except:
 531                             raise ParseError("Cannot find reply to message `%s'" % n)
 532                 except ParseError as e:
 533                     self.exceptions.append(e)
 534                     remove.append(n)
 535
 536             self.messages_by_json[jn] = {k: v for k, v in j.items() if k not in remove}