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| # Protocol Buffers - Google's data interchange format | |
| # Copyright 2008 Google Inc. All rights reserved. | |
| # | |
| # Use of this source code is governed by a BSD-style | |
| # license that can be found in the LICENSE file or at | |
| # https://developers.google.com/open-source/licenses/bsd | |
| """Dynamic Protobuf class creator.""" | |
| from collections import OrderedDict | |
| import hashlib | |
| import os | |
| from google.protobuf import descriptor_pb2 | |
| from google.protobuf import descriptor | |
| from google.protobuf import descriptor_pool | |
| from google.protobuf import message_factory | |
| def _GetMessageFromFactory(pool, full_name): | |
| """Get a proto class from the MessageFactory by name. | |
| Args: | |
| pool: a descriptor pool. | |
| full_name: str, the fully qualified name of the proto type. | |
| Returns: | |
| A class, for the type identified by full_name. | |
| Raises: | |
| KeyError, if the proto is not found in the factory's descriptor pool. | |
| """ | |
| proto_descriptor = pool.FindMessageTypeByName(full_name) | |
| proto_cls = message_factory.GetMessageClass(proto_descriptor) | |
| return proto_cls | |
| def MakeSimpleProtoClass(fields, full_name=None, pool=None): | |
| """Create a Protobuf class whose fields are basic types. | |
| Note: this doesn't validate field names! | |
| Args: | |
| fields: dict of {name: field_type} mappings for each field in the proto. If | |
| this is an OrderedDict the order will be maintained, otherwise the | |
| fields will be sorted by name. | |
| full_name: optional str, the fully-qualified name of the proto type. | |
| pool: optional DescriptorPool instance. | |
| Returns: | |
| a class, the new protobuf class with a FileDescriptor. | |
| """ | |
| pool_instance = pool or descriptor_pool.DescriptorPool() | |
| if full_name is not None: | |
| try: | |
| proto_cls = _GetMessageFromFactory(pool_instance, full_name) | |
| return proto_cls | |
| except KeyError: | |
| # The factory's DescriptorPool doesn't know about this class yet. | |
| pass | |
| # Get a list of (name, field_type) tuples from the fields dict. If fields was | |
| # an OrderedDict we keep the order, but otherwise we sort the field to ensure | |
| # consistent ordering. | |
| field_items = fields.items() | |
| if not isinstance(fields, OrderedDict): | |
| field_items = sorted(field_items) | |
| # Use a consistent file name that is unlikely to conflict with any imported | |
| # proto files. | |
| fields_hash = hashlib.sha1() | |
| for f_name, f_type in field_items: | |
| fields_hash.update(f_name.encode('utf-8')) | |
| fields_hash.update(str(f_type).encode('utf-8')) | |
| proto_file_name = fields_hash.hexdigest() + '.proto' | |
| # If the proto is anonymous, use the same hash to name it. | |
| if full_name is None: | |
| full_name = ('net.proto2.python.public.proto_builder.AnonymousProto_' + | |
| fields_hash.hexdigest()) | |
| try: | |
| proto_cls = _GetMessageFromFactory(pool_instance, full_name) | |
| return proto_cls | |
| except KeyError: | |
| # The factory's DescriptorPool doesn't know about this class yet. | |
| pass | |
| # This is the first time we see this proto: add a new descriptor to the pool. | |
| pool_instance.Add( | |
| _MakeFileDescriptorProto(proto_file_name, full_name, field_items)) | |
| return _GetMessageFromFactory(pool_instance, full_name) | |
| def _MakeFileDescriptorProto(proto_file_name, full_name, field_items): | |
| """Populate FileDescriptorProto for MessageFactory's DescriptorPool.""" | |
| package, name = full_name.rsplit('.', 1) | |
| file_proto = descriptor_pb2.FileDescriptorProto() | |
| file_proto.name = os.path.join(package.replace('.', '/'), proto_file_name) | |
| file_proto.package = package | |
| desc_proto = file_proto.message_type.add() | |
| desc_proto.name = name | |
| for f_number, (f_name, f_type) in enumerate(field_items, 1): | |
| field_proto = desc_proto.field.add() | |
| field_proto.name = f_name | |
| # # If the number falls in the reserved range, reassign it to the correct | |
| # # number after the range. | |
| if f_number >= descriptor.FieldDescriptor.FIRST_RESERVED_FIELD_NUMBER: | |
| f_number += ( | |
| descriptor.FieldDescriptor.LAST_RESERVED_FIELD_NUMBER - | |
| descriptor.FieldDescriptor.FIRST_RESERVED_FIELD_NUMBER + 1) | |
| field_proto.number = f_number | |
| field_proto.label = descriptor_pb2.FieldDescriptorProto.LABEL_OPTIONAL | |
| field_proto.type = f_type | |
| return file_proto | |