114 lines
4.1 KiB
Python
114 lines
4.1 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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# http://code.google.com/p/protobuf/
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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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"""Provides a factory class for generating dynamic messages."""
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__author__ = 'matthewtoia@google.com (Matt Toia)'
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from google.protobuf import descriptor_database
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from google.protobuf import descriptor_pool
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from google.protobuf import message
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from google.protobuf import reflection
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class MessageFactory(object):
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"""Factory for creating Proto2 messages from descriptors in a pool."""
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def __init__(self):
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"""Initializes a new factory."""
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self._classes = {}
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def GetPrototype(self, descriptor):
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"""Builds a proto2 message class based on the passed in descriptor.
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Passing a descriptor with a fully qualified name matching a previous
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invocation will cause the same class to be returned.
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Args:
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descriptor: The descriptor to build from.
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Returns:
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A class describing the passed in descriptor.
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"""
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if descriptor.full_name not in self._classes:
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result_class = reflection.GeneratedProtocolMessageType(
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descriptor.name.encode('ascii', 'ignore'),
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(message.Message,),
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{'DESCRIPTOR': descriptor})
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self._classes[descriptor.full_name] = result_class
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for field in descriptor.fields:
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if field.message_type:
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self.GetPrototype(field.message_type)
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return self._classes[descriptor.full_name]
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_DB = descriptor_database.DescriptorDatabase()
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_POOL = descriptor_pool.DescriptorPool(_DB)
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_FACTORY = MessageFactory()
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def GetMessages(file_protos):
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"""Builds a dictionary of all the messages available in a set of files.
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Args:
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file_protos: A sequence of file protos to build messages out of.
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Returns:
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A dictionary containing all the message types in the files mapping the
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fully qualified name to a Message subclass for the descriptor.
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"""
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result = {}
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for file_proto in file_protos:
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_DB.Add(file_proto)
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for file_proto in file_protos:
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for desc in _GetAllDescriptors(file_proto.message_type, file_proto.package):
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result[desc.full_name] = _FACTORY.GetPrototype(desc)
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return result
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def _GetAllDescriptors(desc_protos, package):
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"""Gets all levels of nested message types as a flattened list of descriptors.
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Args:
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desc_protos: The descriptor protos to process.
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package: The package where the protos are defined.
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Yields:
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Each message descriptor for each nested type.
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"""
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for desc_proto in desc_protos:
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name = '.'.join((package, desc_proto.name))
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yield _POOL.FindMessageTypeByName(name)
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for nested_desc in _GetAllDescriptors(desc_proto.nested_type, name):
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yield nested_desc
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