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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. | |
"""A database of Python protocol buffer generated symbols. | |
SymbolDatabase is the MessageFactory for messages generated at compile time, | |
and makes it easy to create new instances of a registered type, given only the | |
type's protocol buffer symbol name. | |
Example usage:: | |
db = symbol_database.SymbolDatabase() | |
# Register symbols of interest, from one or multiple files. | |
db.RegisterFileDescriptor(my_proto_pb2.DESCRIPTOR) | |
db.RegisterMessage(my_proto_pb2.MyMessage) | |
db.RegisterEnumDescriptor(my_proto_pb2.MyEnum.DESCRIPTOR) | |
# The database can be used as a MessageFactory, to generate types based on | |
# their name: | |
types = db.GetMessages(['my_proto.proto']) | |
my_message_instance = types['MyMessage']() | |
# The database's underlying descriptor pool can be queried, so it's not | |
# necessary to know a type's filename to be able to generate it: | |
filename = db.pool.FindFileContainingSymbol('MyMessage') | |
my_message_instance = db.GetMessages([filename])['MyMessage']() | |
# This functionality is also provided directly via a convenience method: | |
my_message_instance = db.GetSymbol('MyMessage')() | |
""" | |
from google.protobuf.internal import api_implementation | |
from google.protobuf import descriptor_pool | |
from google.protobuf import message_factory | |
class SymbolDatabase(message_factory.MessageFactory): | |
"""A database of Python generated symbols.""" | |
def RegisterMessage(self, message): | |
"""Registers the given message type in the local database. | |
Calls to GetSymbol() and GetMessages() will return messages registered here. | |
Args: | |
message: A :class:`google.protobuf.message.Message` subclass (or | |
instance); its descriptor will be registered. | |
Returns: | |
The provided message. | |
""" | |
desc = message.DESCRIPTOR | |
self._classes[desc] = message | |
self.RegisterMessageDescriptor(desc) | |
return message | |
def RegisterMessageDescriptor(self, message_descriptor): | |
"""Registers the given message descriptor in the local database. | |
Args: | |
message_descriptor (Descriptor): the message descriptor to add. | |
""" | |
if api_implementation.Type() == 'python': | |
# pylint: disable=protected-access | |
self.pool._AddDescriptor(message_descriptor) | |
def RegisterEnumDescriptor(self, enum_descriptor): | |
"""Registers the given enum descriptor in the local database. | |
Args: | |
enum_descriptor (EnumDescriptor): The enum descriptor to register. | |
Returns: | |
EnumDescriptor: The provided descriptor. | |
""" | |
if api_implementation.Type() == 'python': | |
# pylint: disable=protected-access | |
self.pool._AddEnumDescriptor(enum_descriptor) | |
return enum_descriptor | |
def RegisterServiceDescriptor(self, service_descriptor): | |
"""Registers the given service descriptor in the local database. | |
Args: | |
service_descriptor (ServiceDescriptor): the service descriptor to | |
register. | |
""" | |
if api_implementation.Type() == 'python': | |
# pylint: disable=protected-access | |
self.pool._AddServiceDescriptor(service_descriptor) | |
def RegisterFileDescriptor(self, file_descriptor): | |
"""Registers the given file descriptor in the local database. | |
Args: | |
file_descriptor (FileDescriptor): The file descriptor to register. | |
""" | |
if api_implementation.Type() == 'python': | |
# pylint: disable=protected-access | |
self.pool._InternalAddFileDescriptor(file_descriptor) | |
def GetSymbol(self, symbol): | |
"""Tries to find a symbol in the local database. | |
Currently, this method only returns message.Message instances, however, if | |
may be extended in future to support other symbol types. | |
Args: | |
symbol (str): a protocol buffer symbol. | |
Returns: | |
A Python class corresponding to the symbol. | |
Raises: | |
KeyError: if the symbol could not be found. | |
""" | |
return self._classes[self.pool.FindMessageTypeByName(symbol)] | |
def GetMessages(self, files): | |
# TODO(amauryfa): Fix the differences with MessageFactory. | |
"""Gets all registered messages from a specified file. | |
Only messages already created and registered will be returned; (this is the | |
case for imported _pb2 modules) | |
But unlike MessageFactory, this version also returns already defined nested | |
messages, but does not register any message extensions. | |
Args: | |
files (list[str]): The file names to extract messages from. | |
Returns: | |
A dictionary mapping proto names to the message classes. | |
Raises: | |
KeyError: if a file could not be found. | |
""" | |
def _GetAllMessages(desc): | |
"""Walk a message Descriptor and recursively yields all message names.""" | |
yield desc | |
for msg_desc in desc.nested_types: | |
for nested_desc in _GetAllMessages(msg_desc): | |
yield nested_desc | |
result = {} | |
for file_name in files: | |
file_desc = self.pool.FindFileByName(file_name) | |
for msg_desc in file_desc.message_types_by_name.values(): | |
for desc in _GetAllMessages(msg_desc): | |
try: | |
result[desc.full_name] = self._classes[desc] | |
except KeyError: | |
# This descriptor has no registered class, skip it. | |
pass | |
return result | |
_DEFAULT = SymbolDatabase(pool=descriptor_pool.Default()) | |
def Default(): | |
"""Returns the default SymbolDatabase.""" | |
return _DEFAULT | |