src/vpp-api/vapi/vapi_json_parser.py

   1 #!/usr/bin/env python2
   2
   3 import json
   4
   5
   6 def msg_is_reply(name):
   7     return name.endswith('_reply') or name.endswith('_details') \
   8         or name.endswith('_event') or name.endswith('_counters')
   9
  10
  11 class ParseError (Exception):
  12     pass
  13
  14
  15 magic_prefix = "vl_api_"
  16 magic_suffix = "_t"
  17
  18
  19 def remove_magic(what):
  20     if what.startswith(magic_prefix) and what.endswith(magic_suffix):
  21         return what[len(magic_prefix): - len(magic_suffix)]
  22     return what
  23
  24
  25 class Field(object):
  26
  27     def __init__(
  28             self,
  29             field_name,
  30             field_type,
  31             array_len=None,
  32             nelem_field=None):
  33         self.name = field_name
  34         self.type = field_type
  35         self.len = array_len
  36         self.nelem_field = nelem_field
  37
  38     def __str__(self):
  39         if self.len is None:
  40             return "name: %s, type: %s" % (self.name, self.type)
  41         elif self.len > 0:
  42             return "name: %s, type: %s, length: %s" % (self.name, self.type,
  43                                                        self.len)
  44         else:
  45             return ("name: %s, type: %s, variable length stored in: %s" %
  46                     (self.name, self.type, self.nelem_field))
  47
  48
  49 class Type(object):
  50     def __init__(self, name):
  51         self.name = name
  52
  53     def __str__(self):
  54         return self.name
  55
  56
  57 class SimpleType (Type):
  58
  59     def __init__(self, name):
  60         super(SimpleType, self).__init__(name)
  61
  62     def __str__(self):
  63         return self.name
  64
  65
  66 def get_msg_header_defs(struct_type_class, field_class, typedict):
  67     return [
  68         struct_type_class(['msg_header1_t',
  69                            ['u16', '_vl_msg_id'],
  70                            ['u32', 'context'],
  71                            ],
  72                           typedict, field_class
  73                           ),
  74         struct_type_class(['msg_header2_t',
  75                            ['u16', '_vl_msg_id'],
  76                            ['u32', 'client_index'],
  77                            ['u32', 'context'],
  78                            ],
  79                           typedict, field_class
  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
  91     def __str__(self):
  92         return "[%s]" % "], [".join([str(f) for f in self.fields])
  93
  94
  95 class Message(object):
  96
  97     def __init__(self, logger, definition, typedict,
  98                  struct_type_class, simple_type_class, field_class):
  99         self.request = None
 100         self.logger = logger
 101         m = definition
 102         logger.debug("Parsing message definition `%s'" % m)
 103         name = m[0]
 104         self.name = name
 105         logger.debug("Message name is `%s'" % name)
 106         ignore = True
 107         self.header = None
 108         fields = []
 109         for header in get_msg_header_defs(struct_type_class, field_class,
 110                                           typedict):
 111             logger.debug("Probing header `%s'" % header.name)
 112             if header.is_part_of_def(m[1:]):
 113                 self.header = header
 114                 logger.debug("Found header `%s'" % header.name)
 115                 fields.append(field_class(field_name='header',
 116                                           field_type=self.header))
 117                 ignore = False
 118                 break
 119         if ignore and not msg_is_reply(name):
 120             raise ParseError("While parsing message `%s': could not find all "
 121                              "common header fields" % name)
 122         for field in m[1:]:
 123             if len(field) == 1 and 'crc' in field:
 124                 self.crc = field['crc']
 125                 logger.debug("Found CRC `%s'" % self.crc)
 126                 continue
 127             else:
 128                 field_type = field[0]
 129                 if field_type in typedict:
 130                     field_type = typedict[field_type]
 131                 else:
 132                     mundane_field_type = remove_magic(field_type)
 133                     if mundane_field_type in typedict:
 134                         field_type = typedict[mundane_field_type]
 135                     else:
 136                         raise ParseError(
 137                             "While parsing message `%s': could not find "
 138                             "type by magic name `%s' nor by mundane name "
 139                             "`%s'" % (name, field_type, mundane_field_type))
 140                 if len(field) == 2:
 141                     if self.header is not None and\
 142                             self.header.has_field(field[1]):
 143                         continue
 144                     p = field_class(field_name=field[1],
 145                                     field_type=field_type)
 146                 elif len(field) == 3:
 147                     if field[2] == 0:
 148                         raise ParseError(
 149                             "While parsing message `%s': variable length "
 150                             "array `%s' doesn't have reference to member "
 151                             "containing the actual length" % (
 152                                 name, field[1]))
 153                     p = field_class(
 154                         field_name=field[1],
 155                         field_type=field_type,
 156                         array_len=field[2])
 157                 elif len(field) == 4:
 158                     nelem_field = None
 159                     for f in fields:
 160                         if f.name == field[3]:
 161                             nelem_field = f
 162                     if nelem_field is None:
 163                         raise ParseError(
 164                             "While parsing message `%s': couldn't find "
 165                             "variable length array `%s' member containing "
 166                             "the actual length `%s'" % (
 167                                 name, field[1], field[3]))
 168                     p = field_class(
 169                         field_name=field[1],
 170                         field_type=field_type,
 171                         array_len=field[2],
 172                         nelem_field=nelem_field)
 173                 else:
 174                     raise Exception("Don't know how to parse message "
 175                                     "definition for message `%s': `%s'" %
 176                                     (m, m[1:]))
 177                 logger.debug("Parsed field `%s'" % p)
 178                 fields.append(p)
 179         self.fields = fields
 180
 181     def is_dump(self):
 182         return self.name.endswith('_dump')
 183
 184     def is_reply(self):
 185         return msg_is_reply(self.name)
 186
 187
 188 class StructType (Type, Struct):
 189
 190     def __init__(self, definition, typedict, field_class):
 191         t = definition
 192         name = t[0]
 193         fields = []
 194         for field in t[1:]:
 195             if len(field) == 1 and 'crc' in field:
 196                 self.crc = field['crc']
 197                 continue
 198             elif len(field) == 2:
 199                 p = field_class(field_name=field[1],
 200                                 field_type=typedict[field[0]])
 201             elif len(field) == 3:
 202                 if field[2] == 0:
 203                     raise ParseError("While parsing type `%s': array `%s' has "
 204                                      "variable length" % (name, field[1]))
 205                 p = field_class(field_name=field[1],
 206                                 field_type=typedict[field[0]],
 207                                 array_len=field[2])
 208             else:
 209                 raise ParseError(
 210                     "Don't know how to parse type definition for "
 211                     "type `%s': `%s'" % (t, t[1:]))
 212             fields.append(p)
 213         Type.__init__(self, name)
 214         Struct.__init__(self, name, fields)
 215
 216     def __str__(self):
 217         return "StructType(%s, %s)" % (Type.__str__(self),
 218                                        Struct.__str__(self))
 219
 220     def has_field(self, name):
 221         return name in self.field_names
 222
 223     def is_part_of_def(self, definition):
 224         for idx in range(len(self.fields)):
 225             field = definition[idx]
 226             p = self.fields[idx]
 227             if field[1] != p.name:
 228                 return False
 229             if field[0] != p.type.name:
 230                 raise ParseError(
 231                     "Unexpected field type `%s' (should be `%s'), "
 232                     "while parsing msg/def/field `%s/%s/%s'" %
 233                     (field[0], p.type, p.name, definition, field))
 234         return True
 235
 236
 237 class JsonParser(object):
 238     def __init__(self, logger, files, simple_type_class=SimpleType,
 239                  struct_type_class=StructType, field_class=Field,
 240                  message_class=Message):
 241         self.messages = {}
 242         self.types = {
 243             x: simple_type_class(x) for x in [
 244                 'i8', 'i16', 'i32', 'i64',
 245                 'u8', 'u16', 'u32', 'u64',
 246                 'f64'
 247             ]
 248         }
 249
 250         self.simple_type_class = simple_type_class
 251         self.struct_type_class = struct_type_class
 252         self.field_class = field_class
 253         self.message_class = message_class
 254
 255         self.exceptions = []
 256         self.json_files = []
 257         self.types_by_json = {}
 258         self.messages_by_json = {}
 259         self.logger = logger
 260         for f in files:
 261             self.parse_json_file(f)
 262         self.finalize_parsing()
 263
 264     def parse_json_file(self, path):
 265         self.logger.info("Parsing json api file: `%s'" % path)
 266         self.json_files.append(path)
 267         self.types_by_json[path] = {}
 268         self.messages_by_json[path] = {}
 269         with open(path) as f:
 270             j = json.load(f)
 271             for t in j['types']:
 272                 try:
 273                     type_ = self.struct_type_class(t, self.types,
 274                                                    self.field_class)
 275                     if type_.name in self.types:
 276                         raise ParseError("Duplicate type `%s'" % type_.name)
 277                 except ParseError as e:
 278                     self.exceptions.append(e)
 279                     continue
 280                 self.types[type_.name] = type_
 281                 self.types_by_json[path][type_.name] = type_
 282                 self.logger.debug("Parsed type: %s" % type_)
 283             for m in j['messages']:
 284                 try:
 285                     msg = self.message_class(self.logger, m, self.types,
 286                                              self.struct_type_class,
 287                                              self.simple_type_class,
 288                                              self.field_class)
 289                     if msg.name in self.messages:
 290                         raise ParseError("Duplicate message `%s'" % msg.name)
 291                 except ParseError as e:
 292                     self.exceptions.append(e)
 293                     continue
 294                 self.messages[msg.name] = msg
 295                 self.messages_by_json[path][msg.name] = msg
 296
 297     def get_reply(self, message):
 298         if self.messages[message].is_dump():
 299             return self.messages["%s_details" % message[:-len("_dump")]]
 300         return self.messages["%s_reply" % message]
 301
 302     def finalize_parsing(self):
 303         if len(self.messages) == 0:
 304             for e in self.exceptions:
 305                 self.logger.error(e)
 306             raise Exception("No messages parsed.")
 307         for jn, j in self.messages_by_json.items():
 308             remove = []
 309             for n, m in j.items():
 310                 try:
 311                     if not m.is_reply():
 312                         try:
 313                             m.reply = self.get_reply(n)
 314                             m.reply.request = m
 315                         except:
 316                             raise ParseError(
 317                                 "Cannot find reply to message `%s'" % n)
 318                 except ParseError as e:
 319                     self.exceptions.append(e)
 320                     remove.append(n)
 321
 322             self.messages_by_json[jn] = {
 323                 k: v for k, v in j.items() if k not in remove}