163 lines
6.5 KiB
Python
163 lines
6.5 KiB
Python
|
# 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.
|
||
|
|
|
||
|
|
"""Provides a factory class for generating dynamic messages.
|
||
|
|
|
||
|
|
The easiest way to use this class is if you have access to the FileDescriptor
|
||
|
|
protos containing the messages you want to create you can just do the following:
|
||
|
|
|
||
|
|
message_classes = message_factory.GetMessages(iterable_of_file_descriptors)
|
||
|
|
my_proto_instance = message_classes['some.proto.package.MessageName']()
|
||
|
|
"""
|
||
|
|
|
||
|
|
__author__ = 'matthewtoia@google.com (Matt Toia)'
|
||
|
|
|
||
|
|
from google.protobuf.internal import api_implementation
|
||
|
|
from google.protobuf import descriptor_pool
|
||
|
|
from google.protobuf import message
|
||
|
|
|
||
|
|
if api_implementation.Type() == 'cpp':
|
||
|
|
from google.protobuf.pyext import cpp_message as message_impl
|
||
|
|
else:
|
||
|
|
from google.protobuf.internal import python_message as message_impl
|
||
|
|
|
||
|
|
|
||
|
|
# The type of all Message classes.
|
||
|
|
_GENERATED_PROTOCOL_MESSAGE_TYPE = message_impl.GeneratedProtocolMessageType
|
||
|
|
|
||
|
|
|
||
|
|
class MessageFactory(object):
|
||
|
|
"""Factory for creating Proto2 messages from descriptors in a pool."""
|
||
|
|
|
||
|
|
def __init__(self, pool=None):
|
||
|
|
"""Initializes a new factory."""
|
||
|
|
self.pool = pool or descriptor_pool.DescriptorPool()
|
||
|
|
|
||
|
|
# local cache of all classes built from protobuf descriptors
|
||
|
|
self._classes = {}
|
||
|
|
|
||
|
|
def GetPrototype(self, descriptor):
|
||
|
|
"""Builds a proto2 message class based on the passed in descriptor.
|
||
|
|
|
||
|
|
Passing a descriptor with a fully qualified name matching a previous
|
||
|
|
invocation will cause the same class to be returned.
|
||
|
|
|
||
|
|
Args:
|
||
|
|
descriptor: The descriptor to build from.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
A class describing the passed in descriptor.
|
||
|
|
"""
|
||
|
|
if descriptor not in self._classes:
|
||
|
|
descriptor_name = descriptor.name
|
||
|
|
if str is bytes: # PY2
|
||
|
|
descriptor_name = descriptor.name.encode('ascii', 'ignore')
|
||
|
|
result_class = _GENERATED_PROTOCOL_MESSAGE_TYPE(
|
||
|
|
descriptor_name,
|
||
|
|
(message.Message,),
|
||
|
|
{'DESCRIPTOR': descriptor, '__module__': None})
|
||
|
|
# pylint: disable=protected-access
|
||
|
|
result_class._FACTORY = self
|
||
|
|
# If module not set, it wrongly points to message_factory module.
|
||
|
|
self._classes[descriptor] = result_class
|
||
|
|
for field in descriptor.fields:
|
||
|
|
if field.message_type:
|
||
|
|
self.GetPrototype(field.message_type)
|
||
|
|
for extension in result_class.DESCRIPTOR.extensions:
|
||
|
|
if extension.containing_type not in self._classes:
|
||
|
|
self.GetPrototype(extension.containing_type)
|
||
|
|
extended_class = self._classes[extension.containing_type]
|
||
|
|
extended_class.RegisterExtension(extension)
|
||
|
|
return self._classes[descriptor]
|
||
|
|
|
||
|
|
def GetMessages(self, files):
|
||
|
|
"""Gets all the messages from a specified file.
|
||
|
|
|
||
|
|
This will find and resolve dependencies, failing if the descriptor
|
||
|
|
pool cannot satisfy them.
|
||
|
|
|
||
|
|
Args:
|
||
|
|
files: The file names to extract messages from.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
A dictionary mapping proto names to the message classes. This will include
|
||
|
|
any dependent messages as well as any messages defined in the same file as
|
||
|
|
a specified message.
|
||
|
|
"""
|
||
|
|
result = {}
|
||
|
|
for file_name in files:
|
||
|
|
file_desc = self.pool.FindFileByName(file_name)
|
||
|
|
for desc in file_desc.message_types_by_name.values():
|
||
|
|
result[desc.full_name] = self.GetPrototype(desc)
|
||
|
|
|
||
|
|
# While the extension FieldDescriptors are created by the descriptor pool,
|
||
|
|
# the python classes created in the factory need them to be registered
|
||
|
|
# explicitly, which is done below.
|
||
|
|
#
|
||
|
|
# The call to RegisterExtension will specifically check if the
|
||
|
|
# extension was already registered on the object and either
|
||
|
|
# ignore the registration if the original was the same, or raise
|
||
|
|
# an error if they were different.
|
||
|
|
|
||
|
|
for extension in file_desc.extensions_by_name.values():
|
||
|
|
if extension.containing_type not in self._classes:
|
||
|
|
self.GetPrototype(extension.containing_type)
|
||
|
|
extended_class = self._classes[extension.containing_type]
|
||
|
|
extended_class.RegisterExtension(extension)
|
||
|
|
return result
|
||
|
|
|
||
|
|
|
||
|
|
_FACTORY = MessageFactory()
|
||
|
|
|
||
|
|
|
||
|
|
def GetMessages(file_protos):
|
||
|
|
"""Builds a dictionary of all the messages available in a set of files.
|
||
|
|
|
||
|
|
Args:
|
||
|
|
file_protos: Iterable of FileDescriptorProto to build messages out of.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
A dictionary mapping proto names to the message classes. This will include
|
||
|
|
any dependent messages as well as any messages defined in the same file as
|
||
|
|
a specified message.
|
||
|
|
"""
|
||
|
|
# The cpp implementation of the protocol buffer library requires to add the
|
||
|
|
# message in topological order of the dependency graph.
|
||
|
|
file_by_name = {file_proto.name: file_proto for file_proto in file_protos}
|
||
|
|
def _AddFile(file_proto):
|
||
|
|
for dependency in file_proto.dependency:
|
||
|
|
if dependency in file_by_name:
|
||
|
|
# Remove from elements to be visited, in order to cut cycles.
|
||
|
|
_AddFile(file_by_name.pop(dependency))
|
||
|
|
_FACTORY.pool.Add(file_proto)
|
||
|
|
while file_by_name:
|
||
|
|
_AddFile(file_by_name.popitem()[1])
|
||
|
|
return _FACTORY.GetMessages([file_proto.name for file_proto in file_protos])
|