extras/japi/java/jvpp/gen/jvppgen/jvpp_model.py

   1 #!/usr/bin/env python2
   2 #
   3 # Copyright (c) 2018 Cisco and/or its affiliates.
   4 # Licensed under the Apache License, Version 2.0 (the "License");
   5 # you may not use this file except in compliance with the License.
   6 # You may obtain a copy of the License at:
   7 #
   8 #     http://www.apache.org/licenses/LICENSE-2.0
   9 #
  10 # Unless required by applicable law or agreed to in writing, software
  11 # distributed under the License is distributed on an "AS IS" BASIS,
  12 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13 # See the License for the specific language governing permissions and
  14 # limitations under the License.
  15 #
  16 import json
  17 import pprint
  18 from collections import OrderedDict
  19
  20 import binascii
  21
  22 BASE_PACKAGE = "io.fd.vpp.jvpp"
  23
  24
  25 class ParseException(Exception):
  26     pass
  27
  28
  29 class Type(object):
  30     def __init__(self, name, java_name, java_name_fqn, jni_signature, jni_type, jni_accessor,
  31                  host_to_net_function, net_to_host_function):
  32         """
  33         Initializes Type class.
  34
  35         :param name: name of type as defined in .api file, e.g. u8, u32[] or mac_entry
  36         :param java_name: corresponding java name, e.g. byte, int[] or MacEntry
  37         :param java_name_fqn: fully qualified java name, e.g. io.fd.vpp.jvpp.core.types.MacEntry
  38         :param jni_signature: JNI Type signature, e.g. B, [I or Lio.fd.vpp.jvpp.core.types.MacEntry;
  39                               See https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/types.html#type_signatures
  40         :param jni_type: JNI reference type, e.g. jbyte jintArray, jobject
  41                          See https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/types.html#reference_types
  42         :param jni_accessor: Java type do by used in Get<type>Field, Set<type>Field and other functions.
  43                              See https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/functions.html#accessing_fields_of_objects
  44         :param host_to_net_function: name of function host to net byte order swap function
  45         :param net_to_host_function: name of function net to host byte order swap function
  46         """
  47         self.name = name
  48         self.java_name = java_name
  49
  50         # Java generation specific properties, TODO(VPP-1186): move to Java specific subclass
  51         self.java_name_fqn = java_name_fqn
  52
  53         # JNI generation specific properties, TODO(VPP-1186): move to JNI specific subclass
  54         self.jni_signature = jni_signature
  55
  56         # Native type, see:
  57         # https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/types.html#primitive_types
  58         # and
  59         # https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/types.html#reference_types
  60         self.jni_type = jni_type
  61
  62         # Java type do by used in Get<type>Field, Set<type>Field and other functions, see:
  63         # https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/functions.html#accessing_fields_of_objects
  64         self.jni_accessor = jni_accessor
  65
  66         self.host_to_net_function = host_to_net_function
  67         self.net_to_host_function = net_to_host_function
  68         self.is_swap_needed = host_to_net_function and net_to_host_function
  69
  70
  71 class SimpleType(Type):
  72     def __init__(self, name, java_name, jni_signature, jni_type, jni_accessor,
  73                  host_to_net_function=None, net_to_host_function=None):
  74         super(SimpleType, self).__init__(
  75             name=name,
  76             java_name=java_name,
  77             java_name_fqn=java_name,
  78             jni_signature=jni_signature,
  79             jni_type=jni_type,
  80             jni_accessor=jni_accessor,
  81             host_to_net_function=host_to_net_function,
  82             net_to_host_function=net_to_host_function
  83         )
  84         self.vpp_name = name
  85
  86     def get_host_to_net_function(self, host_ref_name, net_ref_name):
  87         return "%s = %s(%s)" % (net_ref_name, self.host_to_net_function, host_ref_name)
  88
  89     def __str__(self):
  90         return "SimpleType{name:%s, java_name:%s}" % (self.name, self.java_name)
  91
  92
  93 # TODO(VPP-1187): add array host to net functions to reduce number of members and simplify JNI generation
  94 class Array(Type):
  95     def __init__(self, base_type, name=None):
  96         if name is None:
  97             name = base_type.name + _ARRAY_SUFFIX
  98         super(Array, self).__init__(
  99             name=name,
 100             java_name=base_type.java_name + _ARRAY_SUFFIX,
 101             java_name_fqn=base_type.java_name_fqn + _ARRAY_SUFFIX,
 102             jni_signature="[%s" % base_type.jni_signature,
 103             jni_type="%sArray" % base_type.jni_type,
 104             jni_accessor="Object",
 105             host_to_net_function=base_type.host_to_net_function,
 106             net_to_host_function=base_type.net_to_host_function
 107         )
 108         self.base_type = base_type
 109
 110     def get_host_to_net_function(self, host_ref_name, net_ref_name):
 111         return self.base_type.get_host_to_net_function(host_ref_name, net_ref_name)
 112
 113     def __str__(self):
 114         return "Array{name:%s, java_name:%s}" % (self.name, self.java_name)
 115
 116
 117 class Enum(Type):
 118     def __init__(self, name, value, constants, definition, plugin_name):
 119         _java_name = _underscore_to_camelcase_upper(name)
 120
 121         super(Enum, self).__init__(
 122             name=name,
 123             java_name=_java_name,
 124             java_name_fqn="io.fd.vpp.jvpp.%s.types.%s" % (plugin_name, _java_name),
 125             jni_signature="Lio/fd/vpp/jvpp/%s/types/%s;" % (plugin_name, _java_name),
 126             jni_type="jobject",
 127             jni_accessor="Object",
 128             host_to_net_function="_host_to_net_%s" % name,
 129             net_to_host_function="_net_to_host_%s" % name
 130         )
 131
 132         self.value = value
 133         self.constants = constants
 134         self.doc = _message_to_javadoc(definition)
 135         self.java_name_lower = _underscore_to_camelcase_lower(name)
 136         self.vpp_name = "%s%s%s" % (_VPP_TYPE_PREFIX, name, _VPP_TYPE_SUFFIX)
 137         # Fully qualified class name used by FindClass function, see:
 138         # https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/functions.html#FindClass
 139         self.jni_name = "io/fd/vpp/jvpp/%s/types/%s" % (plugin_name, _java_name)
 140
 141     def get_host_to_net_function(self, host_ref_name, net_ref_name):
 142         return "_host_to_net_%s(env, %s, &(%s))" % (self.name, host_ref_name, net_ref_name)
 143
 144
 145 class Class(Type):
 146     def __init__(self, name, crc, fields, definition, plugin_name):
 147         _java_name = _underscore_to_camelcase_upper(name)
 148
 149         super(Class, self).__init__(
 150             name=name,
 151             java_name=_java_name,
 152             java_name_fqn="io.fd.vpp.jvpp.%s.types.%s" % (plugin_name, _java_name),
 153             jni_signature="Lio/fd/vpp/jvpp/%s/types/%s;" % (plugin_name, _java_name),
 154             jni_type="jobject",
 155             jni_accessor="Object",
 156             host_to_net_function="_host_to_net_%s" % name,
 157             net_to_host_function="_net_to_host_%s" % name
 158         )
 159
 160         self.crc = crc
 161         self.fields = fields
 162         self.doc = _message_to_javadoc(definition)
 163         self.java_name_lower = _underscore_to_camelcase_lower(name)
 164         self.vpp_name = "%s%s%s" % (_VPP_TYPE_PREFIX, name, _VPP_TYPE_SUFFIX)
 165         # Fully qualified class name used by FindClass function, see:
 166         # https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/functions.html#FindClass
 167         self.jni_name = "io/fd/vpp/jvpp/%s/types/%s" % (plugin_name, _java_name)
 168
 169     def get_host_to_net_function(self, host_ref_name, net_ref_name):
 170         return "_host_to_net_%s(env, %s, &(%s))" % (self.name, host_ref_name, net_ref_name)
 171
 172
 173 class Union(Type):
 174     def __init__(self, name, crc, fields, definition, plugin_name):
 175         _java_name = _underscore_to_camelcase_upper(name)
 176
 177         super(Union, self).__init__(
 178             name=name,
 179             java_name=_java_name,
 180             java_name_fqn="io.fd.vpp.jvpp.%s.types.%s" % (plugin_name, _java_name),
 181             jni_signature="Lio/fd/vpp/jvpp/%s/types/%s;" % (plugin_name, _java_name),
 182             jni_type="jobject",
 183             jni_accessor="Object",
 184             host_to_net_function="_host_to_net_%s" % name,
 185             net_to_host_function="_net_to_host_%s" % name
 186         )
 187
 188         self.crc = crc
 189         self.fields = fields
 190         self.doc = _message_to_javadoc(definition)
 191         self.java_name_lower = _underscore_to_camelcase_lower(name)
 192         self.vpp_name = "%s%s%s" % (_VPP_TYPE_PREFIX, name, _VPP_TYPE_SUFFIX)
 193         # Fully qualified class name used by FindClass function, see:
 194         # https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/functions.html#FindClass
 195         self.jni_name = "io/fd/vpp/jvpp/%s/types/%s" % (plugin_name, _java_name)
 196
 197     def get_host_to_net_function(self, host_ref_name, net_ref_name):
 198         return "_host_to_net_%s(env, %s, &(%s))" % (self.name, host_ref_name, net_ref_name)
 199
 200
 201 class Field(object):
 202     def __init__(self, name, field_type, array_len=None, array_len_field=None):
 203         self.name = name
 204         self.java_name = _underscore_to_camelcase_lower(name)
 205         self.java_name_upper = _underscore_to_camelcase_upper(name)
 206         self.type = field_type
 207         self.array_len = array_len
 208         self.array_len_field = array_len_field
 209
 210     def __str__(self):
 211         return "Field{name:%s, java_name:%s, type:%s}" % (self.name, self.java_name, self.type)
 212
 213
 214 class Message(object):
 215     def __init__(self, name, crc, fields, definition):
 216         self.name = name
 217         self.java_name_upper = _underscore_to_camelcase_upper(name)
 218         self.java_name_lower = _underscore_to_camelcase_lower(name)
 219         self.crc = crc[2:]
 220         self.fields = fields
 221         self.has_fields = fields != []
 222         self.doc = _message_to_javadoc(definition)
 223
 224     def __str__(self):
 225         return "Message{name:%s, java_name:%s, crc:%s, fields:%s}" % (
 226             self.name, self.java_name_upper, self.crc, self.fields)
 227
 228
 229 class Event(Message):
 230     def __init__(self, name, crc, fields, definition):
 231         super(Event, self).__init__(name, crc, fields, definition)
 232
 233
 234 class Request(Message):
 235     def __init__(self, name, reply, crc, fields, definition):
 236         super(Request, self).__init__(name, crc, fields, definition)
 237         self.reply = reply
 238         self.reply_java = _underscore_to_camelcase_upper(reply)
 239
 240     def __str__(self):
 241         return "Request{name:%s, reply:%s, crc:%s, fields:%s}" % (self.name, self.reply, self.crc, self.fields)
 242
 243
 244 class Reply(Message):
 245     def __init__(self, name, request, crc, fields, definition):
 246         super(Reply, self).__init__(name, crc, fields, definition)
 247         self.request = request
 248         self.request_java = _underscore_to_camelcase_upper(request)
 249
 250     def __str__(self):
 251         return "Reply{name:%s, request:%s, crc:%s, fields:%s}" % (self.name, self.request, self.crc, self.fields)
 252
 253
 254 class Dump(Message):
 255     def __init__(self, name, details, crc, fields, definition):
 256         super(Dump, self).__init__(name, crc, fields, definition)
 257         self.details = details
 258         self.reply_java = _underscore_to_camelcase_upper(details)
 259
 260     def __str__(self):
 261         return "Dump{name:%s, details:%s, crc:%s, fields:%s}" % (self.name, self.details, self.crc, self.fields)
 262
 263
 264 class Details(Message):
 265     def __init__(self, name, dump, crc, fields, definition):
 266         super(Details, self).__init__(name, crc, fields, definition)
 267         self.dump = dump
 268         self.request_java = _underscore_to_camelcase_upper(dump)
 269
 270     def __str__(self):
 271         return "Details{name:%s, dump:%s, crc:%s, fields:%s}" % (self.name, self.dump, self.crc, self.fields)
 272
 273
 274 def is_retval(field):
 275     return field.name == u'retval'
 276
 277
 278 def is_array(field):
 279     return field.array_len is not None
 280
 281
 282 def is_request(msg):
 283     return hasattr(msg, 'reply')
 284
 285
 286 def is_reply(msg):
 287     return hasattr(msg, 'request')
 288
 289
 290 def is_dump(msg):
 291     return hasattr(msg, 'details')
 292
 293
 294 def is_details(msg):
 295     return hasattr(msg, 'dump')
 296
 297
 298 def is_event(msg):
 299     return isinstance(msg, Event)
 300
 301
 302 def is_control_ping(msg):
 303     return msg.name == u'control_ping'
 304
 305
 306 def is_control_ping_reply(msg):
 307     return msg.name == u'control_ping_reply'
 308
 309
 310 def crc(block):
 311     s = str(block).encode()
 312     return binascii.crc32(s) & 0xffffffff
 313
 314
 315 class JVppModel(object):
 316     def __init__(self, logger, json_api_files, plugin_name):
 317         self.logger = logger
 318         # TODO(VPP-1188): provide json_file_by_definition map to improve javadoc
 319         self.json_api_files = json_api_files
 320         self.plugin_package = BASE_PACKAGE + "." + plugin_name
 321         self.plugin_name = plugin_name
 322         self.plugin_java_name = _underscore_to_camelcase_upper(plugin_name)
 323         self._load_json_files(json_api_files)
 324         self._parse_services()
 325         self._parse_messages()
 326         self._validate_messages()
 327
 328     def _load_json_files(self, json_api_files):
 329         types = {}
 330         self._messages = []
 331         self._services = {}
 332         self._aliases = {}
 333         for file_name in json_api_files:
 334             with open(file_name) as f:
 335                 j = json.load(f)
 336                 types.update({d[0]: {'type': 'enum', 'data': d} for d in j['enums']})
 337                 types.update({d[0]: {'type': 'type', 'data': d} for d in j['types']})
 338                 types.update({d[0]: {'type': 'union', 'data': d} for d in j['unions']})
 339                 self._messages.extend(j['messages'])
 340                 self._services.update(j['services'])
 341                 self._aliases.update(j['aliases'])
 342
 343         self._parse_types(types)
 344
 345     def _parse_aliases(self, types):
 346
 347         # model aliases
 348         for alias_name in self._aliases:
 349             alias = self._aliases[alias_name]
 350             alias_type = {"type": "type"}
 351             java_name_lower = _underscore_to_camelcase_lower(alias_name)
 352             vpp_type = alias["type"]
 353             crc_value = '0x%08x' % crc(alias_name)
 354             if "length" in alias:
 355                 length = alias["length"]
 356                 alias_type["data"] = [
 357                     alias_name,
 358                     [
 359                         vpp_type,
 360                         java_name_lower,
 361                         length
 362                     ],
 363                     {
 364                         "crc": crc_value
 365                     }
 366                 ]
 367             else:
 368                 alias_type["data"] = [
 369                     alias_name,
 370                     [
 371                         vpp_type,
 372                         java_name_lower
 373                     ],
 374                     {
 375                         "crc": crc_value
 376                     }
 377                 ]
 378
 379             types[alias_name] = alias_type
 380
 381     def _parse_types(self, types):
 382         self._parse_simple_types()
 383         self._parse_aliases(types)
 384         i = 0
 385         while True:
 386             unresolved = {}
 387             for name, value in types.items():
 388                 if name in self._types_by_name:
 389                     continue
 390
 391                 type = value['type']
 392                 data = value['data'][1:]
 393                 try:
 394                     if type == 'enum':
 395                         type = self._parse_enum(name, data)
 396                     elif type == 'union':
 397                         type = self._parse_union(name, data)
 398                     elif type == 'type':
 399                         type = self._parse_type(name, data)
 400                     else:
 401                         self.logger.warning("Unsupported type %s. Ignoring...", type)
 402                         continue
 403
 404                     self._types_by_name[name] = type
 405                     self._types_by_name[name + _ARRAY_SUFFIX] = Array(type)
 406                 except ParseException as e:
 407                     self.logger.debug("Failed to parse %s type in iteration %s: %s.", name, i, e)
 408                     unresolved[name] = value
 409             if len(unresolved) == 0:
 410                 break
 411             if i > 3:
 412                 raise ParseException('Unresolved type definitions {}'
 413                                      .format(unresolved))
 414             types = unresolved
 415             i += 1
 416
 417         self.types = self._types_by_name.values()
 418
 419     def _parse_simple_types(self):
 420         # Mapping according to:
 421         # http://docs.oracle.com/javase/7/do+'[]'cs/technotes/guides/jni/spec/types.html
 422         # and
 423         # https://docs.oracle.com/javase/8/docs/technotes/guides/jni/spec/functions.html#Get_type_Field_routines
 424         #
 425         # Unsigned types are converted to signed java types that have the same size.
 426         # It is the API user responsibility to interpret them correctly.
 427
 428         self._types_by_name = OrderedDict({
 429             'u8': SimpleType('u8', 'byte', 'B', 'jbyte', 'Byte'),
 430             'i8': SimpleType('i8', 'byte', 'B', 'jbyte', 'Byte'),
 431             'u16': SimpleType('u16', 'short', 'S', 'jshort', 'Short',
 432                               host_to_net_function='clib_host_to_net_u16',
 433                               net_to_host_function='clib_net_to_host_u16'),
 434             'i16': SimpleType('i16', 'short', 'S', 'jshort', 'Short',
 435                               host_to_net_function='clib_host_to_net_i16',
 436                               net_to_host_function='clib_net_to_host_i16'),
 437             'u32': SimpleType('u32', 'int', 'I', 'jint', 'Int',
 438                               host_to_net_function='clib_host_to_net_u32',
 439                               net_to_host_function='clib_net_to_host_u32'),
 440             'i32': SimpleType('i32', 'int', 'I', 'jint', 'Int',
 441                               host_to_net_function='clib_host_to_net_i32',
 442                               net_to_host_function='clib_net_to_host_i32'),
 443             'u64': SimpleType('u64', 'long', 'J', 'jlong', 'Long',
 444                               host_to_net_function='clib_host_to_net_u64',
 445                               net_to_host_function='clib_net_to_host_u64'),
 446             'i64': SimpleType('i64', 'long', 'J', 'jlong', 'Long',
 447                               host_to_net_function='clib_host_to_net_i64',
 448                               net_to_host_function='clib_net_to_host_i64'),
 449             'f64': SimpleType('f64', 'double', 'D', 'jdouble', 'Double'),
 450             'string': SimpleType('string', 'String', 'l', 'jstring', 'Object',
 451                                  host_to_net_function='_host_to_net_string',
 452                                  net_to_host_function='_net_to_host_string')
 453         })
 454
 455         for n, t in self._types_by_name.items():
 456             self._types_by_name[n + _ARRAY_SUFFIX] = Array(t)
 457
 458     def _parse_enum(self, name, definition):
 459         self.logger.debug("Parsing enum %s: %s", name, definition)
 460         constants = []
 461         type_name = None
 462         for item in definition:
 463             if type(item) is dict and 'enumtype' in item:
 464                 type_name = item['enumtype']
 465                 continue
 466             constants.append({'name': item[0], 'value': item[1]})
 467         if not type_name:
 468             raise ParseException("'enumtype' was not defined for %s" % definition)
 469         return Enum(name, Field('value', self._types_by_name[type_name]), constants, definition, self.plugin_name)
 470
 471     def _parse_union(self, name, definition):
 472         self.logger.debug("Parsing union %s: %s", name, definition)
 473         crc, fields = self._parse_fields(definition)
 474         return Union(name, crc, fields, definition, self.plugin_name)
 475
 476     def _parse_type(self, name, definition):
 477         self.logger.debug("Parsing type %s: %s", name, definition)
 478         crc, fields = self._parse_fields(definition)
 479         return Class(name, crc, fields, definition, self.plugin_name)
 480
 481     def _parse_services(self):
 482         self._dumps_by_details = {}
 483         self._requests_by_reply = {}
 484         for name, service in self._services.iteritems():
 485             if _is_stream(service):
 486                 self._dumps_by_details[service['reply']] = name
 487             else:
 488                 self._requests_by_reply[service['reply']] = name
 489
 490     def _parse_messages(self):
 491         # Preserve ordering from JSON file to make debugging easier.
 492         self._messages_by_name = OrderedDict()
 493         for msg in self._messages:
 494             try:
 495                 name = msg[0]
 496                 definition = msg[1:]
 497                 self._messages_by_name[name] = self._parse_message(name, definition)
 498             except ParseException as e:
 499                 self.logger.warning("Failed to parse message %s: %s. Skipping message.", name, e)
 500
 501     def _parse_message(self, name, definition):
 502         self.logger.debug("Parsing message %s: %s", name, definition)
 503         crc, fields = self._parse_fields(definition)
 504         if name in self._services:
 505             service = self._services[name]
 506             reply = service['reply']
 507             if _is_stream(service):
 508                 return Dump(name, reply, crc, filter(_is_request_field, fields), definition)
 509             if reply:
 510                 return Request(name, reply, crc, filter(_is_request_field, fields), definition)
 511             else:
 512                 return Event(name, crc, filter(_is_request_field, fields), definition)
 513         elif name in self._requests_by_reply:
 514             return Reply(name, self._requests_by_reply[name], crc, filter(_is_reply_field, fields), definition)
 515         elif name in self._dumps_by_details:
 516             return Details(name, self._dumps_by_details[name], crc, filter(_is_reply_field, fields), definition)
 517         else:
 518             # TODO: some messages like combined_counters are not visible in the services.
 519             # Throw exception instead (requires fixing vppagigen).
 520             return Event(name, crc, filter(_is_request_field, fields), definition)
 521
 522     def _parse_fields(self, definition):
 523         crc = None
 524         fields = []
 525         for item in definition:
 526             if type(item) == dict and 'crc' in item:
 527                 crc = item['crc']
 528             else:
 529                 fields.append(self._parse_field(item, fields))
 530         if not crc:
 531             raise ParseException("CRC was not defined for %s" % definition)
 532         return crc, fields
 533
 534     def _parse_field(self, field, fields):
 535         type_name = _extract_type_name(field[0])
 536
 537         if type_name in self._types_by_name:
 538             if len(field) > 2:
 539                 # Array field
 540                 array_len_field = None
 541                 if len(field) == 4:
 542                     for f in fields:
 543                         if f.name == field[3]:
 544                             array_len_field = f
 545                     if not array_len_field:
 546                         raise ParseException("Could not find field %s declared as length of array %s",
 547                                              field[3], field[1])
 548                 return Field(field[1], self._types_by_name[type_name + _ARRAY_SUFFIX], field[2], array_len_field)
 549             else:
 550                 return Field(field[1], self._types_by_name[type_name])
 551         else:
 552             raise ParseException("Unknown field type %s" % field)
 553
 554     def _validate_messages(self):
 555         """
 556         In case if message A is known to be reply for message B, and message B was not correctly parsed,
 557         remove message A from the set of all messages.
 558         """
 559         to_be_removed = []
 560         messages = self._messages_by_name
 561         for name, msg in messages.iteritems():
 562             if (is_request(msg) and msg.reply not in messages) \
 563                     or (is_reply(msg) and msg.request not in messages) \
 564                     or (is_dump(msg) and msg.details not in messages) \
 565                     or (is_details(msg) and msg.dump not in messages):
 566                 to_be_removed.append(name)
 567
 568         for name in to_be_removed:
 569             del messages[name]
 570
 571         self.messages = self._messages_by_name.values()
 572
 573
 574 _ARRAY_SUFFIX = '[]'
 575
 576
 577 def _underscore_to_camelcase_upper(name):
 578     return name.title().replace("_", "")
 579
 580
 581 def _underscore_to_camelcase_lower(name):
 582     name = name.title().replace("_", "")
 583     return name[0].lower() + name[1:]
 584
 585
 586 def _message_to_javadoc(message_definition):
 587     """ Converts JSON message definition to javadoc """
 588     formatted_message = pprint.pformat(message_definition, indent=4, width=120, depth=None)
 589     return " * " + formatted_message.replace("\n", "\n * ")
 590
 591
 592 def _is_stream(service):
 593     """
 594     Checks if service represents stream, e.g.:
 595     "ip_address_dump": {
 596         "reply": "ip_address_details",
 597         "stream": true
 598     }
 599     :param service: JSON definition of service
 600     :return: value assigned to "stream" or None
 601     """
 602     return "stream" in service
 603
 604
 605 def _extract_type_name(name):
 606     if name.startswith(_VPP_TYPE_PREFIX) and name.endswith(_VPP_TYPE_SUFFIX):
 607         return name[len(_VPP_TYPE_PREFIX): - len(_VPP_TYPE_SUFFIX)]
 608     return name
 609
 610 _VPP_TYPE_PREFIX = "vl_api_"
 611
 612 _VPP_TYPE_SUFFIX = "_t"
 613
 614
 615 def _is_request_field(field):
 616     # Skip fields that are hidden to the jvpp user (handled by JNI layer)
 617     return field.name not in {'_vl_msg_id', 'client_index', 'context'}
 618
 619
 620 def _is_reply_field(field):
 621     # Skip fields that are hidden to the jvpp user:
 622     # _vl_msg_id is handled at JNI layer,
 623     # Unlike in the request case, context is visible to allow matching replies with requests at Java layer.
 624     return field.name not in {'_vl_msg_id'}