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# 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, 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: 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
# 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'
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
factory.pool.Add(file_proto)
return _GetMessageFromFactory(factory, full_name)
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