135 lines
5.4 KiB
Python
135 lines
5.4 KiB
Python
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# Protocol Buffers - Google's data interchange format
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# Copyright 2008 Google Inc. All rights reserved.
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# https://developers.google.com/protocol-buffers/
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are
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# met:
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#
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# * Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# * Redistributions in binary form must reproduce the above
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# copyright notice, this list of conditions and the following disclaimer
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# in the documentation and/or other materials provided with the
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# distribution.
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# * Neither the name of Google Inc. nor the names of its
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# contributors may be used to endorse or promote products derived from
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# this software without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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"""Dynamic Protobuf class creator."""
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from collections import OrderedDict
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import hashlib
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import os
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from google.protobuf import descriptor_pb2
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from google.protobuf import descriptor
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from google.protobuf import descriptor_pool
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from google.protobuf import message_factory
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def _GetMessageFromFactory(pool, full_name):
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"""Get a proto class from the MessageFactory by name.
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Args:
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pool: a descriptor pool.
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full_name: str, the fully qualified name of the proto type.
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Returns:
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A class, for the type identified by full_name.
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Raises:
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KeyError, if the proto is not found in the factory's descriptor pool.
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"""
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proto_descriptor = pool.FindMessageTypeByName(full_name)
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proto_cls = message_factory.GetMessageClass(proto_descriptor)
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return proto_cls
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def MakeSimpleProtoClass(fields, full_name=None, pool=None):
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"""Create a Protobuf class whose fields are basic types.
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Note: this doesn't validate field names!
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Args:
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fields: dict of {name: field_type} mappings for each field in the proto. If
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this is an OrderedDict the order will be maintained, otherwise the
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fields will be sorted by name.
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full_name: optional str, the fully-qualified name of the proto type.
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pool: optional DescriptorPool instance.
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Returns:
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a class, the new protobuf class with a FileDescriptor.
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"""
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pool_instance = pool or descriptor_pool.DescriptorPool()
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if full_name is not None:
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try:
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proto_cls = _GetMessageFromFactory(pool_instance, full_name)
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return proto_cls
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except KeyError:
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# The factory's DescriptorPool doesn't know about this class yet.
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pass
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# Get a list of (name, field_type) tuples from the fields dict. If fields was
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# an OrderedDict we keep the order, but otherwise we sort the field to ensure
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# consistent ordering.
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field_items = fields.items()
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if not isinstance(fields, OrderedDict):
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field_items = sorted(field_items)
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# Use a consistent file name that is unlikely to conflict with any imported
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# proto files.
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fields_hash = hashlib.sha1()
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for f_name, f_type in field_items:
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fields_hash.update(f_name.encode('utf-8'))
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fields_hash.update(str(f_type).encode('utf-8'))
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proto_file_name = fields_hash.hexdigest() + '.proto'
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# If the proto is anonymous, use the same hash to name it.
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if full_name is None:
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full_name = ('net.proto2.python.public.proto_builder.AnonymousProto_' +
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fields_hash.hexdigest())
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try:
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proto_cls = _GetMessageFromFactory(pool_instance, full_name)
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return proto_cls
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except KeyError:
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# The factory's DescriptorPool doesn't know about this class yet.
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pass
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# This is the first time we see this proto: add a new descriptor to the pool.
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pool_instance.Add(
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_MakeFileDescriptorProto(proto_file_name, full_name, field_items))
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return _GetMessageFromFactory(pool_instance, full_name)
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def _MakeFileDescriptorProto(proto_file_name, full_name, field_items):
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"""Populate FileDescriptorProto for MessageFactory's DescriptorPool."""
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package, name = full_name.rsplit('.', 1)
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file_proto = descriptor_pb2.FileDescriptorProto()
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file_proto.name = os.path.join(package.replace('.', '/'), proto_file_name)
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file_proto.package = package
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desc_proto = file_proto.message_type.add()
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desc_proto.name = name
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for f_number, (f_name, f_type) in enumerate(field_items, 1):
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field_proto = desc_proto.field.add()
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field_proto.name = f_name
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# # If the number falls in the reserved range, reassign it to the correct
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# # number after the range.
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if f_number >= descriptor.FieldDescriptor.FIRST_RESERVED_FIELD_NUMBER:
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f_number += (
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descriptor.FieldDescriptor.LAST_RESERVED_FIELD_NUMBER -
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descriptor.FieldDescriptor.FIRST_RESERVED_FIELD_NUMBER + 1)
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field_proto.number = f_number
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field_proto.label = descriptor_pb2.FieldDescriptorProto.LABEL_OPTIONAL
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field_proto.type = f_type
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return file_proto
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