def GroupDecoder(field_number, is_repeated, is_packed, key, new_default):
    """Returns a decoder for a group field."""

    end_tag_bytes = encoder.TagBytes(field_number,
                                     wire_format.WIRETYPE_END_GROUP)
    end_tag_len = len(end_tag_bytes)

    assert not is_packed
    if is_repeated:
        tag_bytes = encoder.TagBytes(field_number,
                                     wire_format.WIRETYPE_START_GROUP)
        tag_len = len(tag_bytes)

        def DecodeRepeatedField(buffer, pos, end, message, field_dict):
            value = field_dict.get(key)
            if value is None:
                value = field_dict.setdefault(key, new_default(message))
            while 1:
                value = field_dict.get(key)
                if value is None:
                    value = field_dict.setdefault(key, new_default(message))
                # Read sub-message.
                pos = value.add()._InternalParse(buffer, pos, end)
                # Read end tag.
                new_pos = pos + end_tag_len
                if buffer[pos:new_pos] != end_tag_bytes or new_pos > end:
                    raise _DecodeError('Missing group end tag.')
                # Predict that the next tag is another copy of the same repeated field.
                pos = new_pos + tag_len
                if buffer[new_pos:pos] != tag_bytes or new_pos == end:
                    # Prediction failed.  Return.
                    return new_pos

        return DecodeRepeatedField
    else:

        def DecodeField(buffer, pos, end, message, field_dict):
            value = field_dict.get(key)
            if value is None:
                value = field_dict.setdefault(key, new_default(message))
            # Read sub-message.
            pos = value._InternalParse(buffer, pos, end)
            # Read end tag.
            new_pos = pos + end_tag_len
            if buffer[pos:new_pos] != end_tag_bytes or new_pos > end:
                raise _DecodeError('Missing group end tag.')
            return new_pos

        return DecodeField
 def DecodePackedField(buffer, pos, end, message, field_dict):
     value = field_dict.get(key)
     if value is None:
         value = field_dict.setdefault(key, new_default(message))
     (endpoint, pos) = local_DecodeVarint(buffer, pos)
     endpoint += pos
     if endpoint > end:
         raise _DecodeError('Truncated message.')
     while pos < endpoint:
         value_start_pos = pos
         (element, pos) = _DecodeSignedVarint32(buffer, pos)
         if element in enum_type.values_by_number:
             value.append(element)
         else:
             if not message._unknown_fields:
                 message._unknown_fields = []
             tag_bytes = encoder.TagBytes(field_number,
                                          wire_format.WIRETYPE_VARINT)
             message._unknown_fields.append(
                 (tag_bytes, buffer[value_start_pos:pos]))
     if pos > endpoint:
         if element in enum_type.values_by_number:
             del value[-1]  # Discard corrupt value.
         else:
             del message._unknown_fields[-1]
         raise _DecodeError('Packed element was truncated.')
     return pos
    def SpecificDecoder(field_number, is_repeated, is_packed, key,
                        new_default):
        if is_packed:
            local_DecodeVarint = _DecodeVarint

            def DecodePackedField(buffer, pos, end, message, field_dict):
                value = field_dict.get(key)
                if value is None:
                    value = field_dict.setdefault(key, new_default(message))
                (endpoint, pos) = local_DecodeVarint(buffer, pos)
                endpoint += pos
                if endpoint > end:
                    raise _DecodeError('Truncated message.')
                while pos < endpoint:
                    (element, pos) = decode_value(buffer, pos)
                    value.append(element)
                if pos > endpoint:
                    del value[-1]  # Discard corrupt value.
                    raise _DecodeError('Packed element was truncated.')
                return pos

            return DecodePackedField
        elif is_repeated:
            tag_bytes = encoder.TagBytes(field_number, wire_type)
            tag_len = len(tag_bytes)

            def DecodeRepeatedField(buffer, pos, end, message, field_dict):
                value = field_dict.get(key)
                if value is None:
                    value = field_dict.setdefault(key, new_default(message))
                while 1:
                    (element, new_pos) = decode_value(buffer, pos)
                    value.append(element)
                    # Predict that the next tag is another copy of the same repeated
                    # field.
                    pos = new_pos + tag_len
                    if buffer[new_pos:pos] != tag_bytes or new_pos >= end:
                        # Prediction failed.  Return.
                        if new_pos > end:
                            raise _DecodeError('Truncated message.')
                        return new_pos

            return DecodeRepeatedField
        else:

            def DecodeField(buffer, pos, end, message, field_dict):
                (field_dict[key], pos) = decode_value(buffer, pos)
                if pos > end:
                    del field_dict[key]  # Discard corrupt value.
                    raise _DecodeError('Truncated message.')
                return pos

            return DecodeField
 def CheckUnknownField(self, name, expected_value):
     field_descriptor = self.descriptor.fields_by_name[name]
     wire_type = type_checkers.FIELD_TYPE_TO_WIRE_TYPE[
         field_descriptor.type]
     field_tag = encoder.TagBytes(field_descriptor.number, wire_type)
     result_dict = {}
     for tag_bytes, value in self.missing_message._unknown_fields:
         if tag_bytes == field_tag:
             decoder = missing_enum_values_pb2.TestEnumValues._decoders_by_tag[
                 tag_bytes][0]
             decoder(value, 0, len(value), self.message, result_dict)
     self.assertEqual(expected_value, result_dict[field_descriptor])
def MessageDecoder(field_number, is_repeated, is_packed, key, new_default):
    """Returns a decoder for a message field."""

    local_DecodeVarint = _DecodeVarint

    assert not is_packed
    if is_repeated:
        tag_bytes = encoder.TagBytes(field_number,
                                     wire_format.WIRETYPE_LENGTH_DELIMITED)
        tag_len = len(tag_bytes)

        def DecodeRepeatedField(buffer, pos, end, message, field_dict):
            value = field_dict.get(key)
            if value is None:
                value = field_dict.setdefault(key, new_default(message))
            while 1:
                # Read length.
                (size, pos) = local_DecodeVarint(buffer, pos)
                new_pos = pos + size
                if new_pos > end:
                    raise _DecodeError('Truncated message.')
                # Read sub-message.
                if value.add()._InternalParse(buffer, pos, new_pos) != new_pos:
                    # The only reason _InternalParse would return early is if it
                    # encountered an end-group tag.
                    raise _DecodeError('Unexpected end-group tag.')
                # Predict that the next tag is another copy of the same repeated field.
                pos = new_pos + tag_len
                if buffer[new_pos:pos] != tag_bytes or new_pos == end:
                    # Prediction failed.  Return.
                    return new_pos

        return DecodeRepeatedField
    else:

        def DecodeField(buffer, pos, end, message, field_dict):
            value = field_dict.get(key)
            if value is None:
                value = field_dict.setdefault(key, new_default(message))
            # Read length.
            (size, pos) = local_DecodeVarint(buffer, pos)
            new_pos = pos + size
            if new_pos > end:
                raise _DecodeError('Truncated message.')
            # Read sub-message.
            if value._InternalParse(buffer, pos, new_pos) != new_pos:
                # The only reason _InternalParse would return early is if it encountered
                # an end-group tag.
                raise _DecodeError('Unexpected end-group tag.')
            return new_pos

        return DecodeField
 def DecodeField(buffer, pos, end, message, field_dict):
     value_start_pos = pos
     (enum_value, pos) = _DecodeSignedVarint32(buffer, pos)
     if pos > end:
         raise _DecodeError('Truncated message.')
     if enum_value in enum_type.values_by_number:
         field_dict[key] = enum_value
     else:
         if not message._unknown_fields:
             message._unknown_fields = []
         tag_bytes = encoder.TagBytes(field_number,
                                      wire_format.WIRETYPE_VARINT)
         message._unknown_fields.append(
             (tag_bytes, buffer[value_start_pos:pos]))
     return pos
def StringDecoder(field_number, is_repeated, is_packed, key, new_default):
    """Returns a decoder for a string field."""

    local_DecodeVarint = _DecodeVarint
    local_unicode = six.text_type

    def _ConvertToUnicode(byte_str):
        try:
            return local_unicode(byte_str, 'utf-8')
        except UnicodeDecodeError as e:
            # add more information to the error message and re-raise it.
            e.reason = '%s in field: %s' % (e, key.full_name)
            raise

    assert not is_packed
    if is_repeated:
        tag_bytes = encoder.TagBytes(field_number,
                                     wire_format.WIRETYPE_LENGTH_DELIMITED)
        tag_len = len(tag_bytes)

        def DecodeRepeatedField(buffer, pos, end, message, field_dict):
            value = field_dict.get(key)
            if value is None:
                value = field_dict.setdefault(key, new_default(message))
            while 1:
                (size, pos) = local_DecodeVarint(buffer, pos)
                new_pos = pos + size
                if new_pos > end:
                    raise _DecodeError('Truncated string.')
                value.append(_ConvertToUnicode(buffer[pos:new_pos]))
                # Predict that the next tag is another copy of the same repeated field.
                pos = new_pos + tag_len
                if buffer[new_pos:pos] != tag_bytes or new_pos == end:
                    # Prediction failed.  Return.
                    return new_pos

        return DecodeRepeatedField
    else:

        def DecodeField(buffer, pos, end, message, field_dict):
            (size, pos) = local_DecodeVarint(buffer, pos)
            new_pos = pos + size
            if new_pos > end:
                raise _DecodeError('Truncated string.')
            field_dict[key] = _ConvertToUnicode(buffer[pos:new_pos])
            return new_pos

        return DecodeField
def MapDecoder(field_descriptor, new_default, is_message_map):
    """Returns a decoder for a map field."""

    key = field_descriptor
    tag_bytes = encoder.TagBytes(field_descriptor.number,
                                 wire_format.WIRETYPE_LENGTH_DELIMITED)
    tag_len = len(tag_bytes)
    local_DecodeVarint = _DecodeVarint
    # Can't read _concrete_class yet; might not be initialized.
    message_type = field_descriptor.message_type

    def DecodeMap(buffer, pos, end, message, field_dict):
        submsg = message_type._concrete_class()
        value = field_dict.get(key)
        if value is None:
            value = field_dict.setdefault(key, new_default(message))
        while 1:
            # Read length.
            (size, pos) = local_DecodeVarint(buffer, pos)
            new_pos = pos + size
            if new_pos > end:
                raise _DecodeError('Truncated message.')
            # Read sub-message.
            submsg.Clear()
            if submsg._InternalParse(buffer, pos, new_pos) != new_pos:
                # The only reason _InternalParse would return early is if it
                # encountered an end-group tag.
                raise _DecodeError('Unexpected end-group tag.')

            if is_message_map:
                value[submsg.key].MergeFrom(submsg.value)
            else:
                value[submsg.key] = submsg.value

            # Predict that the next tag is another copy of the same repeated field.
            pos = new_pos + tag_len
            if buffer[new_pos:pos] != tag_bytes or new_pos == end:
                # Prediction failed.  Return.
                return new_pos

    return DecodeMap
def BytesDecoder(field_number, is_repeated, is_packed, key, new_default):
    """Returns a decoder for a bytes field."""

    local_DecodeVarint = _DecodeVarint

    assert not is_packed
    if is_repeated:
        tag_bytes = encoder.TagBytes(field_number,
                                     wire_format.WIRETYPE_LENGTH_DELIMITED)
        tag_len = len(tag_bytes)

        def DecodeRepeatedField(buffer, pos, end, message, field_dict):
            value = field_dict.get(key)
            if value is None:
                value = field_dict.setdefault(key, new_default(message))
            while 1:
                (size, pos) = local_DecodeVarint(buffer, pos)
                new_pos = pos + size
                if new_pos > end:
                    raise _DecodeError('Truncated string.')
                value.append(buffer[pos:new_pos])
                # Predict that the next tag is another copy of the same repeated field.
                pos = new_pos + tag_len
                if buffer[new_pos:pos] != tag_bytes or new_pos == end:
                    # Prediction failed.  Return.
                    return new_pos

        return DecodeRepeatedField
    else:

        def DecodeField(buffer, pos, end, message, field_dict):
            (size, pos) = local_DecodeVarint(buffer, pos)
            new_pos = pos + size
            if new_pos > end:
                raise _DecodeError('Truncated string.')
            field_dict[key] = buffer[pos:new_pos]
            return new_pos

        return DecodeField
def MessageSetItemDecoder(descriptor):
    """Returns a decoder for a MessageSet item.

  The parameter is the message Descriptor.

  The message set message looks like this:
    message MessageSet {
      repeated group Item = 1 {
        required int32 type_id = 2;
        required string message = 3;
      }
    }
  """

    type_id_tag_bytes = encoder.TagBytes(2, wire_format.WIRETYPE_VARINT)
    message_tag_bytes = encoder.TagBytes(3,
                                         wire_format.WIRETYPE_LENGTH_DELIMITED)
    item_end_tag_bytes = encoder.TagBytes(1, wire_format.WIRETYPE_END_GROUP)

    local_ReadTag = ReadTag
    local_DecodeVarint = _DecodeVarint
    local_SkipField = SkipField

    def DecodeItem(buffer, pos, end, message, field_dict):
        message_set_item_start = pos
        type_id = -1
        message_start = -1
        message_end = -1

        # Technically, type_id and message can appear in any order, so we need
        # a little loop here.
        while 1:
            (tag_bytes, pos) = local_ReadTag(buffer, pos)
            if tag_bytes == type_id_tag_bytes:
                (type_id, pos) = local_DecodeVarint(buffer, pos)
            elif tag_bytes == message_tag_bytes:
                (size, message_start) = local_DecodeVarint(buffer, pos)
                pos = message_end = message_start + size
            elif tag_bytes == item_end_tag_bytes:
                break
            else:
                pos = SkipField(buffer, pos, end, tag_bytes)
                if pos == -1:
                    raise _DecodeError('Missing group end tag.')

        if pos > end:
            raise _DecodeError('Truncated message.')

        if type_id == -1:
            raise _DecodeError('MessageSet item missing type_id.')
        if message_start == -1:
            raise _DecodeError('MessageSet item missing message.')

        extension = message.Extensions._FindExtensionByNumber(type_id)
        if extension is not None:
            value = field_dict.get(extension)
            if value is None:
                value = field_dict.setdefault(
                    extension, extension.message_type._concrete_class())
            if value._InternalParse(buffer, message_start,
                                    message_end) != message_end:
                # The only reason _InternalParse would return early is if it encountered
                # an end-group tag.
                raise _DecodeError('Unexpected end-group tag.')
        else:
            if not message._unknown_fields:
                message._unknown_fields = []
            message._unknown_fields.append(
                (MESSAGE_SET_ITEM_TAG, buffer[message_set_item_start:pos]))

        return pos

    return DecodeItem
def EnumDecoder(field_number, is_repeated, is_packed, key, new_default):
    enum_type = key.enum_type
    if is_packed:
        local_DecodeVarint = _DecodeVarint

        def DecodePackedField(buffer, pos, end, message, field_dict):
            value = field_dict.get(key)
            if value is None:
                value = field_dict.setdefault(key, new_default(message))
            (endpoint, pos) = local_DecodeVarint(buffer, pos)
            endpoint += pos
            if endpoint > end:
                raise _DecodeError('Truncated message.')
            while pos < endpoint:
                value_start_pos = pos
                (element, pos) = _DecodeSignedVarint32(buffer, pos)
                if element in enum_type.values_by_number:
                    value.append(element)
                else:
                    if not message._unknown_fields:
                        message._unknown_fields = []
                    tag_bytes = encoder.TagBytes(field_number,
                                                 wire_format.WIRETYPE_VARINT)
                    message._unknown_fields.append(
                        (tag_bytes, buffer[value_start_pos:pos]))
            if pos > endpoint:
                if element in enum_type.values_by_number:
                    del value[-1]  # Discard corrupt value.
                else:
                    del message._unknown_fields[-1]
                raise _DecodeError('Packed element was truncated.')
            return pos

        return DecodePackedField
    elif is_repeated:
        tag_bytes = encoder.TagBytes(field_number, wire_format.WIRETYPE_VARINT)
        tag_len = len(tag_bytes)

        def DecodeRepeatedField(buffer, pos, end, message, field_dict):
            value = field_dict.get(key)
            if value is None:
                value = field_dict.setdefault(key, new_default(message))
            while 1:
                (element, new_pos) = _DecodeSignedVarint32(buffer, pos)
                if element in enum_type.values_by_number:
                    value.append(element)
                else:
                    if not message._unknown_fields:
                        message._unknown_fields = []
                    message._unknown_fields.append(
                        (tag_bytes, buffer[pos:new_pos]))
                # Predict that the next tag is another copy of the same repeated
                # field.
                pos = new_pos + tag_len
                if buffer[new_pos:pos] != tag_bytes or new_pos >= end:
                    # Prediction failed.  Return.
                    if new_pos > end:
                        raise _DecodeError('Truncated message.')
                    return new_pos

        return DecodeRepeatedField
    else:

        def DecodeField(buffer, pos, end, message, field_dict):
            value_start_pos = pos
            (enum_value, pos) = _DecodeSignedVarint32(buffer, pos)
            if pos > end:
                raise _DecodeError('Truncated message.')
            if enum_value in enum_type.values_by_number:
                field_dict[key] = enum_value
            else:
                if not message._unknown_fields:
                    message._unknown_fields = []
                tag_bytes = encoder.TagBytes(field_number,
                                             wire_format.WIRETYPE_VARINT)
                message._unknown_fields.append(
                    (tag_bytes, buffer[value_start_pos:pos]))
            return pos

        return DecodeField
            new_pos = pos + size
            if new_pos > end:
                raise _DecodeError('Truncated message.')
            # Read sub-message.
            if value._InternalParse(buffer, pos, new_pos) != new_pos:
                # The only reason _InternalParse would return early is if it encountered
                # an end-group tag.
                raise _DecodeError('Unexpected end-group tag.')
            return new_pos

        return DecodeField


# --------------------------------------------------------------------

MESSAGE_SET_ITEM_TAG = encoder.TagBytes(1, wire_format.WIRETYPE_START_GROUP)


def MessageSetItemDecoder(descriptor):
    """Returns a decoder for a MessageSet item.

  The parameter is the message Descriptor.

  The message set message looks like this:
    message MessageSet {
      repeated group Item = 1 {
        required int32 type_id = 2;
        required string message = 3;
      }
    }
  """