1 files changed, 31 insertions, 12 deletions
diff --git a/python/google/protobuf/proto_builder.py b/python/google/protobuf/proto_builder.py
index 700e3c25..736caed3 100644
--- a/python/google/protobuf/proto_builder.py
+++ b/python/google/protobuf/proto_builder.py
@@ -48,7 +48,7 @@ def _GetMessageFromFactory(factory, full_name):
     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.
+    A class, for the type identified by full_name.
   Raises:
     KeyError, if the proto is not found in the factory's descriptor pool.
   """
@@ -57,7 +57,7 @@ def _GetMessageFromFactory(factory, full_name):
   return proto_cls
 
 
-def MakeSimpleProtoClass(fields, full_name, pool=None):
+def MakeSimpleProtoClass(fields, full_name=None, pool=None):
   """Create a Protobuf class whose fields are basic types.
 
   Note: this doesn't validate field names!
@@ -66,18 +66,20 @@ def MakeSimpleProtoClass(fields, full_name, pool=None):
     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: str, the fully-qualified name of the proto type.
+    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)
-  try:
-    proto_cls = _GetMessageFromFactory(factory, full_name)
-    return proto_cls
-  except KeyError:
-    # The factory's DescriptorPool doesn't know about this class yet.
-    pass
+
+  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
@@ -94,6 +96,25 @@ def MakeSimpleProtoClass(fields, full_name, pool=None):
     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)
@@ -106,6 +127,4 @@ def MakeSimpleProtoClass(fields, full_name, pool=None):
     field_proto.number = f_number
     field_proto.label = descriptor_pb2.FieldDescriptorProto.LABEL_OPTIONAL
     field_proto.type = f_type
-
-  factory.pool.Add(file_proto)
-  return _GetMessageFromFactory(factory, full_name)
+  return file_proto