src/vpp-api/vapi/vapi_json_parser.py

   1 #!/usr/bin/env python3
   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:
  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:
  50     def __init__(self, name):
  51         self.name = name
  52
  53
  54 class SimpleType (Type):
  55
  56     def __init__(self, name):
  57         super().__init__(name)
  58
  59     def __str__(self):
  60         return self.name
  61
  62
  63 def get_msg_header_defs(struct_type_class, field_class, typedict):
  64     return [
  65         struct_type_class(['msg_header1_t',
  66                            ['u16', '_vl_msg_id'],
  67                            ['u32', 'context'],
  68                            ],
  69                           typedict, field_class
  70                           ),
  71         struct_type_class(['msg_header2_t',
  72                            ['u16', '_vl_msg_id'],
  73                            ['u32', 'client_index'],
  74                            ['u32', 'context'],
  75                            ],
  76                           typedict, field_class
  77                           ),
  78     ]
  79
  80
  81 class Struct:
  82
  83     def __init__(self, name, fields):
  84         self.name = name
  85         self.fields = fields
  86         self.field_names = [n.name for n in self.fields]
  87
  88
  89 class Message:
  90
  91     def __init__(self, logger, definition, typedict,
  92                  struct_type_class, simple_type_class, field_class):
  93         self.logger = logger
  94         m = definition
  95         logger.debug("Parsing message definition `%s'" % m)
  96         name = m[0]
  97         self.name = name
  98         logger.debug("Message name is `%s'" % name)
  99         ignore = True
 100         self.header = None
 101         fields = []
 102         for header in get_msg_header_defs(struct_type_class, field_class,
 103                                           typedict):
 104             logger.debug("Probing header `%s'" % header.name)
 105             if header.is_part_of_def(m[1:]):
 106                 self.header = header
 107                 logger.debug("Found header `%s'" % header.name)
 108                 fields.append(field_class(field_name='header',
 109                                           field_type=self.header))
 110                 ignore = False
 111                 break
 112         if ignore and not msg_is_reply(name):
 113             raise ParseError("While parsing message `%s': could not find all "
 114                              "common header fields" % name)
 115         for field in m[1:]:
 116             if len(field) == 1 and 'crc' in field:
 117                 self.crc = field['crc']
 118                 logger.debug("Found CRC `%s'" % self.crc)
 119                 continue
 120             else:
 121                 field_type = field[0]
 122                 if field_type in typedict:
 123                     field_type = typedict[field_type]
 124                 else:
 125                     field_type = typedict[remove_magic(field_type)]
 126                 if len(field) == 2:
 127                     if self.header is not None and\
 128                             self.header.has_field(field[1]):
 129                         continue
 130                     p = field_class(field_name=field[1],
 131                                     field_type=field_type)
 132                 elif len(field) == 3:
 133                     if field[2] == 0:
 134                         raise ParseError(
 135                             "While parsing message `%s': variable length "
 136                             "array `%s' doesn't have reference to member "
 137                             "containing the actual length" % (
 138                                 name, field[1]))
 139                     p = field_class(
 140                         field_name=field[1],
 141                         field_type=field_type,
 142                         array_len=field[2])
 143                 elif len(field) == 4:
 144                     nelem_field = None
 145                     for f in fields:
 146                         if f.name == field[3]:
 147                             nelem_field = f
 148                     if nelem_field is None:
 149                         raise ParseError(
 150                             "While parsing message `%s': couldn't find "
 151                             "variable length array `%s' member containing "
 152                             "the actual length `%s'" % (
 153                                 name, field[1], field[3]))
 154                     p = field_class(
 155                         field_name=field[1],
 156                         field_type=field_type,
 157                         array_len=field[2],
 158                         nelem_field=nelem_field)
 159                 else:
 160                     raise Exception("Don't know how to parse message "
 161                                     "definition for message `%s': `%s'" %
 162                                     (m, m[1:]))
 163                 logger.debug("Parsed field `%s'" % p)
 164                 fields.append(p)
 165         self.fields = fields
 166
 167     def is_dump(self):
 168         return self.name.endswith('_dump')
 169
 170     def is_reply(self):
 171         return msg_is_reply(self.name)
 172
 173
 174 class StructType (Type, Struct):
 175
 176     def __init__(self, definition, typedict, field_class):
 177         t = definition
 178         name = t[0]
 179         fields = []
 180         for field in t[1:]:
 181             if len(field) == 1 and 'crc' in field:
 182                 self.crc = field['crc']
 183                 continue
 184             elif len(field) == 2:
 185                 p = field_class(field_name=field[1],
 186                                 field_type=typedict[field[0]])
 187             elif len(field) == 3:
 188                 if field[2] == 0:
 189                     raise ParseError("While parsing type `%s': array `%s' has "
 190                                      "variable length" % (name, field[1]))
 191                 p = field_class(field_name=field[1],
 192                                 field_type=typedict[field[0]],
 193                                 array_len=field[2])
 194             else:
 195                 raise ParseError(
 196                     "Don't know how to parse type definition for "
 197                     "type `%s': `%s'" % (t, t[1:]))
 198             fields.append(p)
 199         Type.__init__(self, name)
 200         Struct.__init__(self, name, fields)
 201
 202     def has_field(self, name):
 203         return name in self.field_names
 204
 205     def is_part_of_def(self, definition):
 206         for idx in range(len(self.fields)):
 207             field = definition[idx]
 208             p = self.fields[idx]
 209             if field[1] != p.name:
 210                 return False
 211             if field[0] != p.type.name:
 212                 raise ParseError(
 213                     "Unexpected field type `%s' (should be `%s'), "
 214                     "while parsing msg/def/field `%s/%s/%s'" %
 215                     (field[0], p.type, p.name, definition, field))
 216         return True
 217
 218
 219 class JsonParser:
 220     def __init__(self, logger, files, simple_type_class=SimpleType,
 221                  struct_type_class=StructType, field_class=Field,
 222                  message_class=Message):
 223         self.messages = {}
 224         self.types = {
 225             x: simple_type_class(x) for x in [
 226                 'i8', 'i16', 'i32', 'i64',
 227                 'u8', 'u16', 'u32', 'u64',
 228                 'f64'
 229             ]
 230         }
 231
 232         self.simple_type_class = simple_type_class
 233         self.struct_type_class = struct_type_class
 234         self.field_class = field_class
 235         self.message_class = message_class
 236
 237         self.exceptions = []
 238         self.json_files = []
 239         self.types_by_json = {}
 240         self.messages_by_json = {}
 241         self.logger = logger
 242         for f in files:
 243             self.parse_json_file(f)
 244         self.finalize_parsing()
 245
 246     def parse_json_file(self, path):
 247         self.logger.info("Parsing json api file: `%s'" % path)
 248         self.json_files.append(path)
 249         self.types_by_json[path] = {}
 250         self.messages_by_json[path] = {}
 251         with open(path) as f:
 252             j = json.load(f)
 253             for t in j['types']:
 254                 try:
 255                     type_ = self.struct_type_class(t, self.types,
 256                                                    self.field_class)
 257                     if type_.name in self.types:
 258                         raise ParseError("Duplicate type `%s'" % type_.name)
 259                 except ParseError as e:
 260                     self.exceptions.append(e)
 261                     continue
 262                 self.types[type_.name] = type_
 263                 self.types_by_json[path][type_.name] = type_
 264             for m in j['messages']:
 265                 try:
 266                     msg = self.message_class(self.logger, m, self.types,
 267                                              self.struct_type_class,
 268                                              self.simple_type_class,
 269                                              self.field_class)
 270                     if msg.name in self.messages:
 271                         raise ParseError("Duplicate message `%s'" % msg.name)
 272                 except ParseError as e:
 273                     self.exceptions.append(e)
 274                     continue
 275                 self.messages[msg.name] = msg
 276                 self.messages_by_json[path][msg.name] = msg
 277
 278     def get_reply(self, message):
 279         if self.messages[message].is_dump():
 280             return self.messages["%s_details" % message[:-len("_dump")]]
 281         return self.messages["%s_reply" % message]
 282
 283     def finalize_parsing(self):
 284         if len(self.messages) == 0:
 285             for e in self.exceptions:
 286                 self.logger.error(e)
 287             raise Exception("No messages parsed.")
 288         for jn, j in self.messages_by_json.items():
 289             remove = []
 290             for n, m in j.items():
 291                 try:
 292                     if not m.is_reply():
 293                         try:
 294                             m.reply = self.get_reply(n)
 295                         except:
 296                             raise ParseError(
 297                                 "Cannot find reply to message `%s'" % n)
 298                 except ParseError as e:
 299                     self.exceptions.append(e)
 300                     remove.append(n)
 301
 302             self.messages_by_json[jn] = {
 303                 k: v for k, v in j.items() if k not in remove}