Sets the field's type, cpp_type, message_type and enum_type.

    Args:
      field_proto: Data about the field in proto format.
      field_desc: The descriptor to modiy.
      package: The package the field's container is in.
      scope: Enclosing scope of available types.

def _SetFieldType(self, field_proto, field_desc, package, scope):
    """Sets the field's type, cpp_type, message_type and enum_type.

    Args:
      field_proto: Data about the field in proto format.
      field_desc: The descriptor to modiy.
      package: The package the field's container is in.
      scope: Enclosing scope of available types.
    """
    if field_proto.type_name:
      desc = self._GetTypeFromScope(package, field_proto.type_name, scope)
    else:
      desc = None

    if not field_proto.HasField('type'):
      if isinstance(desc, descriptor.Descriptor):
        field_proto.type = descriptor.FieldDescriptor.TYPE_MESSAGE
      else:
        field_proto.type = descriptor.FieldDescriptor.TYPE_ENUM

    field_desc.cpp_type = descriptor.FieldDescriptor.ProtoTypeToCppProtoType(
        field_proto.type)

    if (field_proto.type == descriptor.FieldDescriptor.TYPE_MESSAGE
        or field_proto.type == descriptor.FieldDescriptor.TYPE_GROUP):
      field_desc.message_type = desc

    if field_proto.type == descriptor.FieldDescriptor.TYPE_ENUM:
      field_desc.enum_type = desc

    if field_proto.label == descriptor.FieldDescriptor.LABEL_REPEATED:
      field_desc.has_default_value = False
      field_desc.default_value = []
    elif field_proto.HasField('default_value'):
      field_desc.has_default_value = True
      if (field_proto.type == descriptor.FieldDescriptor.TYPE_DOUBLE or
          field_proto.type == descriptor.FieldDescriptor.TYPE_FLOAT):
        field_desc.default_value = float(field_proto.default_value)
      elif field_proto.type == descriptor.FieldDescriptor.TYPE_STRING:
        field_desc.default_value = field_proto.default_value
      elif field_proto.type == descriptor.FieldDescriptor.TYPE_BOOL:
        field_desc.default_value = field_proto.default_value.lower() == 'true'
      elif field_proto.type == descriptor.FieldDescriptor.TYPE_ENUM:
        field_desc.default_value = field_desc.enum_type.values_by_name[
            field_proto.default_value].number
      elif field_proto.type == descriptor.FieldDescriptor.TYPE_BYTES:
        field_desc.default_value = text_encoding.CUnescape(
            field_proto.default_value)
      else:
        # All other types are of the "int" type.
        field_desc.default_value = int(field_proto.default_value)
    else:
      field_desc.has_default_value = False
      if (field_proto.type == descriptor.FieldDescriptor.TYPE_DOUBLE or
          field_proto.type == descriptor.FieldDescriptor.TYPE_FLOAT):
        field_desc.default_value = 0.0
      elif field_proto.type == descriptor.FieldDescriptor.TYPE_STRING:
        field_desc.default_value = u''
      elif field_proto.type == descriptor.FieldDescriptor.TYPE_BOOL:
        field_desc.default_value = False
      elif field_proto.type == descriptor.FieldDescriptor.TYPE_ENUM:
        field_desc.default_value = field_desc.enum_type.values[0].number
      elif field_proto.type == descriptor.FieldDescriptor.TYPE_BYTES:
        field_desc.default_value = b''
      else:
        # All other types are of the "int" type.
        field_desc.default_value = 0

    field_desc.type = field_proto.type