Source Code for Module google.protobuf.reflection

 1  # Protocol Buffers - Google's data interchange format 
 2  # Copyright 2008 Google Inc.  All rights reserved. 
 3  # https://developers.google.com/protocol-buffers/ 
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30   
31  # This code is meant to work on Python 2.4 and above only. 
32   
33  """Contains a metaclass and helper functions used to create 
34  protocol message classes from Descriptor objects at runtime. 
35   
36  Recall that a metaclass is the "type" of a class. 
37  (A class is to a metaclass what an instance is to a class.) 
38   
39  In this case, we use the GeneratedProtocolMessageType metaclass 
40  to inject all the useful functionality into the classes 
41  output by the protocol compiler at compile-time. 
42   
43  The upshot of all this is that the real implementation 
44  details for ALL pure-Python protocol buffers are *here in 
45  this file*. 
46  """ 
47   
48  __author__ = 'robinson@google.com (Will Robinson)' 
49   
50   
51  from google.protobuf import message_factory 
52  from google.protobuf import symbol_database 
53   
54  # The type of all Message classes. 
55  # Part of the public interface, but normally only used by message factories. 
56  GeneratedProtocolMessageType = message_factory._GENERATED_PROTOCOL_MESSAGE_TYPE 
57   
58  MESSAGE_CLASS_CACHE = {} 
59   
60   
61  # Deprecated. Please NEVER use reflection.ParseMessage(). 
62 -def ParseMessage(descriptor, byte_str): 
63    """Generate a new Message instance from this Descriptor and a byte string. 
64   
65    DEPRECATED: ParseMessage is deprecated because it is using MakeClass(). 
66    Please use MessageFactory.GetPrototype() instead. 
67   
68    Args: 
69      descriptor: Protobuf Descriptor object 
70      byte_str: Serialized protocol buffer byte string 
71   
72    Returns: 
73      Newly created protobuf Message object. 
74    """ 
75    result_class = MakeClass(descriptor) 
76    new_msg = result_class() 
77    new_msg.ParseFromString(byte_str) 
78    return new_msg 
79   
80   
81  # Deprecated. Please NEVER use reflection.MakeClass(). 
82 -def MakeClass(descriptor): 
83    """Construct a class object for a protobuf described by descriptor. 
84   
85    DEPRECATED: use MessageFactory.GetPrototype() instead. 
86   
87    Args: 
88      descriptor: A descriptor.Descriptor object describing the protobuf. 
89    Returns: 
90      The Message class object described by the descriptor. 
91    """ 
92    # Original implementation leads to duplicate message classes, which won't play 
93    # well with extensions. Message factory info is also missing. 
94    # Redirect to message_factory. 
95    return symbol_database.Default().GetPrototype(descriptor) 
96