Source Code for Module google.protobuf.proto_builder

  1  # Protocol Buffers - Google's data interchange format 
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 30   
 31  """Dynamic Protobuf class creator.""" 
 32   
 33  try: 
 34      from collections import OrderedDict 
 35  except ImportError: 
 36      from ordereddict import OrderedDict  #PY26 
 37  import hashlib 
 38  import os 
 39   
 40  from google.protobuf import descriptor_pb2 
 41  from google.protobuf import message_factory 
 42   
 43   
 44 -def _GetMessageFromFactory(factory, full_name): 
 45    """Get a proto class from the MessageFactory by name. 
 46   
 47    Args: 
 48      factory: a MessageFactory instance. 
 49      full_name: str, the fully qualified name of the proto type. 
 50    Returns: 
 51      A class, for the type identified by full_name. 
 52    Raises: 
 53      KeyError, if the proto is not found in the factory's descriptor pool. 
 54    """ 
 55    proto_descriptor = factory.pool.FindMessageTypeByName(full_name) 
 56    proto_cls = factory.GetPrototype(proto_descriptor) 
 57    return proto_cls 
 58   
 59   
 60 -def MakeSimpleProtoClass(fields, full_name=None, pool=None): 
 61    """Create a Protobuf class whose fields are basic types. 
 62   
 63    Note: this doesn't validate field names! 
 64   
 65    Args: 
 66      fields: dict of {name: field_type} mappings for each field in the proto. If 
 67          this is an OrderedDict the order will be maintained, otherwise the 
 68          fields will be sorted by name. 
 69      full_name: optional str, the fully-qualified name of the proto type. 
 70      pool: optional DescriptorPool instance. 
 71    Returns: 
 72      a class, the new protobuf class with a FileDescriptor. 
 73    """ 
 74    factory = message_factory.MessageFactory(pool=pool) 
 75   
 76    if full_name is not None: 
 77      try: 
 78        proto_cls = _GetMessageFromFactory(factory, full_name) 
 79        return proto_cls 
 80      except KeyError: 
 81        # The factory's DescriptorPool doesn't know about this class yet. 
 82        pass 
 83   
 84    # Get a list of (name, field_type) tuples from the fields dict. If fields was 
 85    # an OrderedDict we keep the order, but otherwise we sort the field to ensure 
 86    # consistent ordering. 
 87    field_items = fields.items() 
 88    if not isinstance(fields, OrderedDict): 
 89      field_items = sorted(field_items) 
 90   
 91    # Use a consistent file name that is unlikely to conflict with any imported 
 92    # proto files. 
 93    fields_hash = hashlib.sha1() 
 94    for f_name, f_type in field_items: 
 95      fields_hash.update(f_name.encode('utf-8')) 
 96      fields_hash.update(str(f_type).encode('utf-8')) 
 97    proto_file_name = fields_hash.hexdigest() + '.proto' 
 98   
 99    # If the proto is anonymous, use the same hash to name it. 
100    if full_name is None: 
101      full_name = ('net.proto2.python.public.proto_builder.AnonymousProto_' + 
102                   fields_hash.hexdigest()) 
103      try: 
104        proto_cls = _GetMessageFromFactory(factory, full_name) 
105        return proto_cls 
106      except KeyError: 
107        # The factory's DescriptorPool doesn't know about this class yet. 
108        pass 
109   
110    # This is the first time we see this proto: add a new descriptor to the pool. 
111    factory.pool.Add( 
112        _MakeFileDescriptorProto(proto_file_name, full_name, field_items)) 
113    return _GetMessageFromFactory(factory, full_name) 
114   
115   
116 -def _MakeFileDescriptorProto(proto_file_name, full_name, field_items): 
117    """Populate FileDescriptorProto for MessageFactory's DescriptorPool.""" 
118    package, name = full_name.rsplit('.', 1) 
119    file_proto = descriptor_pb2.FileDescriptorProto() 
120    file_proto.name = os.path.join(package.replace('.', '/'), proto_file_name) 
121    file_proto.package = package 
122    desc_proto = file_proto.message_type.add() 
123    desc_proto.name = name 
124    for f_number, (f_name, f_type) in enumerate(field_items, 1): 
125      field_proto = desc_proto.field.add() 
126      field_proto.name = f_name 
127      field_proto.number = f_number 
128      field_proto.label = descriptor_pb2.FieldDescriptorProto.LABEL_OPTIONAL 
129      field_proto.type = f_type 
130    return file_proto 
131