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                 if len(field) == 2:
 171                     if self.header is not None and\
 172                             self.header.has_field(field[1]):
 173                         continue
 174                     p = field_class(field_name=field[1],
 175                                     field_type=field_type)
 176                 elif len(field) == 3:
 177                     if field[2] == 0:
 178                         raise ParseError(
 179                             "While parsing message `%s': variable length "
 180                             "array `%s' doesn't have reference to member "
 181                             "containing the actual length" % (
 182                                 name, field[1]))
 183                     p = field_class(
 184                         field_name=field[1],
 185                         field_type=field_type,
 186                         array_len=field[2])
 187                 elif len(field) == 4:
 188                     nelem_field = None
 189                     for f in fields:
 190                         if f.name == field[3]:
 191                             nelem_field = f
 192                     if nelem_field is None:
 193                         raise ParseError(
 194                             "While parsing message `%s': couldn't find "
 195                             "variable length array `%s' member containing "
 196                             "the actual length `%s'" % (
 197                                 name, field[1], field[3]))
 198                     p = field_class(
 199                         field_name=field[1],
 200                         field_type=field_type,
 201                         array_len=field[2],
 202                         nelem_field=nelem_field)
 203                 else:
 204                     raise Exception("Don't know how to parse message "
 205                                     "definition for message `%s': `%s'" %
 206                                     (m, m[1:]))
 207                 logger.debug("Parsed field `%s'" % p)
 208                 fields.append(p)
 209         self.fields = fields
 210         self.depends = [f.type for f in self.fields]
 211         logger.debug("Parsed message: %s" % self)
 212
 213     def __str__(self):
 214         return "Message(%s, [%s], {crc: %s}" % \
 215             (self.name,
 216              "], [".join([str(f) for f in self.fields]),
 217              self.crc)
 218
 219
 220 class StructType (Type, Struct):
 221
 222     def __init__(self, definition, json_parser, field_class, logger):
 223         t = definition
 224         logger.debug("Parsing struct definition `%s'" % t)
 225         name = t[0]
 226         fields = []
 227         for field in t[1:]:
 228             if len(field) == 1 and 'crc' in field:
 229                 self.crc = field['crc']
 230                 continue
 231             field_type = json_parser.lookup_type_like_id(field[0])
 232             logger.debug("Parsing type field `%s'" % field)
 233             if len(field) == 2:
 234                 p = field_class(field_name=field[1],
 235                                 field_type=field_type)
 236             elif len(field) == 3:
 237                 if field[2] == 0:
 238                     raise ParseError("While parsing type `%s': array `%s' has "
 239                                      "variable length" % (name, field[1]))
 240                 p = field_class(field_name=field[1],
 241                                 field_type=field_type,
 242                                 array_len=field[2])
 243             elif len(field) == 4:
 244                 nelem_field = None
 245                 for f in fields:
 246                     if f.name == field[3]:
 247                         nelem_field = f
 248                 if nelem_field is None:
 249                     raise ParseError(
 250                         "While parsing message `%s': couldn't find "
 251                         "variable length array `%s' member containing "
 252                         "the actual length `%s'" % (
 253                             name, field[1], field[3]))
 254                 p = field_class(field_name=field[1],
 255                                 field_type=field_type,
 256                                 array_len=field[2],
 257                                 nelem_field=nelem_field)
 258             else:
 259                 raise ParseError(
 260                     "Don't know how to parse field `%s' of type definition "
 261                     "for type `%s'" % (field, t))
 262             fields.append(p)
 263         Type.__init__(self, name)
 264         Struct.__init__(self, name, fields)
 265
 266     def __str__(self):
 267         return "StructType(%s, %s)" % (Type.__str__(self),
 268                                        Struct.__str__(self))
 269
 270     def has_field(self, name):
 271         return name in self.field_names
 272
 273     def is_part_of_def(self, definition):
 274         for idx in range(len(self.fields)):
 275             field = definition[idx]
 276             p = self.fields[idx]
 277             if field[1] != p.name:
 278                 return False
 279             if field[0] != p.type.name:
 280                 raise ParseError(
 281                     "Unexpected field type `%s' (should be `%s'), "
 282                     "while parsing msg/def/field `%s/%s/%s'" %
 283                     (field[0], p.type, p.name, definition, field))
 284         return True
 285
 286
 287 class JsonParser(object):
 288     def __init__(self, logger, files, simple_type_class=SimpleType,
 289                  enum_class=Enum, union_class=Union,
 290                  struct_type_class=StructType, field_class=Field,
 291                  message_class=Message, alias_class=Alias):
 292         self.services = {}
 293         self.messages = {}
 294         self.enums = {}
 295         self.unions = {}
 296         self.aliases = {}
 297         self.types = {
 298             x: simple_type_class(x) for x in [
 299                 'i8', 'i16', 'i32', 'i64',
 300                 'u8', 'u16', 'u32', 'u64',
 301                 'f64', 'bool'
 302             ]
 303         }
 304
 305         self.types['string'] = simple_type_class('vl_api_string_t')
 306         self.replies = set()
 307         self.events = set()
 308         self.simple_type_class = simple_type_class
 309         self.enum_class = enum_class
 310         self.union_class = union_class
 311         self.struct_type_class = struct_type_class
 312         self.field_class = field_class
 313         self.alias_class = alias_class
 314         self.message_class = message_class
 315
 316         self.exceptions = []
 317         self.json_files = []
 318         self.types_by_json = {}
 319         self.enums_by_json = {}
 320         self.unions_by_json = {}
 321         self.aliases_by_json = {}
 322         self.messages_by_json = {}
 323         self.logger = logger
 324         for f in files:
 325             self.parse_json_file(f)
 326         self.finalize_parsing()
 327
 328     def parse_json_file(self, path):
 329         self.logger.info("Parsing json api file: `%s'" % path)
 330         self.json_files.append(path)
 331         self.types_by_json[path] = []
 332         self.enums_by_json[path] = []
 333         self.unions_by_json[path] = []
 334         self.aliases_by_json[path] = []
 335         self.messages_by_json[path] = {}
 336         with open(path) as f:
 337             j = json.load(f)
 338             for k in j['services']:
 339                 if k in self.services:
 340                     raise ParseError("Duplicate service `%s'" % k)
 341                 self.services[k] = j['services'][k]
 342                 self.replies.add(self.services[k]["reply"])
 343                 if "events" in self.services[k]:
 344                     for x in self.services[k]["events"]:
 345                         self.events.add(x)
 346             for e in j['enums']:
 347                 name = e[0]
 348                 value_pairs = e[1:-1]
 349                 enumtype = self.types[e[-1]["enumtype"]]
 350                 enum = self.enum_class(name, value_pairs, enumtype)
 351                 self.enums[enum.name] = enum
 352                 self.logger.debug("Parsed enum: %s" % enum)
 353                 self.enums_by_json[path].append(enum)
 354             exceptions = []
 355             progress = 0
 356             last_progress = 0
 357             while True:
 358                 for u in j['unions']:
 359                     name = u[0]
 360                     if name in self.unions:
 361                         progress = progress + 1
 362                         continue
 363                     try:
 364                         type_pairs = [[self.lookup_type_like_id(t), n]
 365                                       for t, n in u[1:-1]]
 366                         crc = u[-1]["crc"]
 367                         union = self.union_class(name, type_pairs, crc)
 368                         progress = progress + 1
 369                     except ParseError as e:
 370                         exceptions.append(e)
 371                         continue
 372                     self.unions[union.name] = union
 373                     self.logger.debug("Parsed union: %s" % union)
 374                     self.unions_by_json[path].append(union)
 375                 for name, body in j['aliases'].iteritems():
 376                     if name in self.aliases:
 377                         progress = progress + 1
 378                         continue
 379                     if 'length' in body:
 380                         array_len = body['length']
 381                     else:
 382                         array_len = None
 383                     t = self.types[body['type']]
 384                     alias = self.alias_class(name, t, array_len)
 385                     self.aliases[name] = alias
 386                     self.logger.debug("Parsed alias: %s" % alias)
 387                     self.aliases_by_json[path].append(alias)
 388                 for t in j['types']:
 389                     if t[0] in self.types:
 390                         progress = progress + 1
 391                         continue
 392                     try:
 393                         type_ = self.struct_type_class(t, self,
 394                                                        self.field_class,
 395                                                        self.logger)
 396                         if type_.name in self.types:
 397                             raise ParseError(
 398                                 "Duplicate type `%s'" % type_.name)
 399                         progress = progress + 1
 400                     except ParseError as e:
 401                         exceptions.append(e)
 402                         continue
 403                     self.types[type_.name] = type_
 404                     self.types_by_json[path].append(type_)
 405                     self.logger.debug("Parsed type: %s" % type_)
 406                 if not exceptions:
 407                     # finished parsing
 408                     break
 409                 if progress <= last_progress:
 410                     # cannot make forward progress
 411                     self.exceptions.extend(exceptions)
 412                     break
 413                 exceptions = []
 414                 last_progress = progress
 415                 progress = 0
 416             prev_length = len(self.messages)
 417             processed = []
 418             while True:
 419                 exceptions = []
 420                 for m in j['messages']:
 421                     if m in processed:
 422                         continue
 423                     try:
 424                         msg = self.message_class(self.logger, m, self)
 425                         if msg.name in self.messages:
 426                             raise ParseError(
 427                                 "Duplicate message `%s'" % msg.name)
 428                     except ParseError as e:
 429                         exceptions.append(e)
 430                         continue
 431                     self.messages[msg.name] = msg
 432                     self.messages_by_json[path][msg.name] = msg
 433                     processed.append(m)
 434                 if prev_length == len(self.messages):
 435                     # cannot make forward progress ...
 436                     self.exceptions.extend(exceptions)
 437                     break
 438                 prev_length = len(self.messages)
 439
 440     def lookup_type_like_id(self, name):
 441         mundane_name = remove_magic(name)
 442         if name in self.types:
 443             return self.types[name]
 444         elif name in self.enums:
 445             return self.enums[name]
 446         elif name in self.unions:
 447             return self.unions[name]
 448         elif name in self.aliases:
 449             return self.aliases[name]
 450         elif mundane_name in self.types:
 451             return self.types[mundane_name]
 452         elif mundane_name in self.enums:
 453             return self.enums[mundane_name]
 454         elif mundane_name in self.unions:
 455             return self.unions[mundane_name]
 456         elif mundane_name in self.aliases:
 457             return self.aliases[mundane_name]
 458         raise ParseError(
 459             "Could not find type, enum or union by magic name `%s' nor by "
 460             "mundane name `%s'" % (name, mundane_name))
 461
 462     def is_reply(self, message):
 463         return message in self.replies
 464
 465     def is_event(self, message):
 466         return message in self.events
 467
 468     def get_reply(self, message):
 469         return self.messages[self.services[message]['reply']]
 470
 471     def finalize_parsing(self):
 472         if len(self.messages) == 0:
 473             for e in self.exceptions:
 474                 self.logger.warning(e)
 475         for jn, j in self.messages_by_json.items():
 476             remove = []
 477             for n, m in j.items():
 478                 try:
 479                     if not m.is_reply and not m.is_event:
 480                         try:
 481                             m.reply = self.get_reply(n)
 482                             if "stream" in self.services[m.name]:
 483                                 m.reply_is_stream = \
 484                                     self.services[m.name]["stream"]
 485                             else:
 486                                 m.reply_is_stream = False
 487                             m.reply.request = m
 488                         except:
 489                             raise ParseError(
 490                                 "Cannot find reply to message `%s'" % n)
 491                 except ParseError as e:
 492                     self.exceptions.append(e)
 493                     remove.append(n)
 494
 495             self.messages_by_json[jn] = {
 496                 k: v for k, v in j.items() if k not in remove}