name : proto_builder.py # Protocol Buffers - Google's data interchange format # Copyright 2008 Google Inc. All rights reserved. # https://developers.google.com/protocol-buffers/ # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are # met: # # * Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # * Redistributions in binary form must reproduce the above # copyright notice, this list of conditions and the following disclaimer # in the documentation and/or other materials provided with the # distribution. # * Neither the name of Google Inc. nor the names of its # contributors may be used to endorse or promote products derived from # this software without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. """Dynamic Protobuf class creator.""" try: from collections import OrderedDict except ImportError: from ordereddict import OrderedDict #PY26 import hashlib import os from google.protobuf import descriptor_pb2 from google.protobuf import message_factory def _GetMessageFromFactory(factory, full_name): """Get a proto class from the MessageFactory by name. Args: factory: a MessageFactory instance. 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 = factory.pool.FindMessageTypeByName(full_name) proto_cls = factory.GetPrototype(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. """ factory = message_factory.MessageFactory(pool=pool) if full_name is not None: try: proto_cls = _GetMessageFromFactory(factory, 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(factory, 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. factory.pool.Add( _MakeFileDescriptorProto(proto_file_name, full_name, field_items)) return _GetMessageFromFactory(factory, 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 field_proto.number = f_number field_proto.label = descriptor_pb2.FieldDescriptorProto.LABEL_OPTIONAL field_proto.type = f_type return file_proto