Squashed 'third_party/protobuf/' content from commit e35e248
Change-Id: I6cbe123d09fe50fdcad0e51466665daeee7433c7
git-subtree-dir: third_party/protobuf
git-subtree-split: e35e24800fb8d694bdeea5fd63dc7d1b14d68723
diff --git a/python/google/protobuf/symbol_database.py b/python/google/protobuf/symbol_database.py
new file mode 100644
index 0000000..87760f2
--- /dev/null
+++ b/python/google/protobuf/symbol_database.py
@@ -0,0 +1,185 @@
+# 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 makes it easy to create new instances of a registered type, given
+only the type's protocol buffer symbol name. Once all symbols are registered,
+they can be accessed using either the MessageFactory interface which
+SymbolDatabase exposes, or the DescriptorPool interface of the underlying
+pool.
+
+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 import descriptor_pool
+
+
+class SymbolDatabase(object):
+ """A database of Python generated symbols.
+
+ SymbolDatabase also models message_factory.MessageFactory.
+
+ The symbol database can be used to keep a global registry of all protocol
+ buffer types used within a program.
+ """
+
+ def __init__(self, pool=None):
+ """Constructor."""
+
+ self._symbols = {}
+ self._symbols_by_file = {}
+ self.pool = pool or descriptor_pool.Default()
+
+ def RegisterMessage(self, message):
+ """Registers the given message type in the local database.
+
+ Args:
+ message: a message.Message, to be registered.
+
+ Returns:
+ The provided message.
+ """
+
+ desc = message.DESCRIPTOR
+ self._symbols[desc.full_name] = message
+ if desc.file.name not in self._symbols_by_file:
+ self._symbols_by_file[desc.file.name] = {}
+ self._symbols_by_file[desc.file.name][desc.full_name] = message
+ self.pool.AddDescriptor(desc)
+ return message
+
+ def RegisterEnumDescriptor(self, enum_descriptor):
+ """Registers the given enum descriptor in the local database.
+
+ Args:
+ enum_descriptor: a descriptor.EnumDescriptor.
+
+ Returns:
+ The provided descriptor.
+ """
+ self.pool.AddEnumDescriptor(enum_descriptor)
+ return enum_descriptor
+
+ def RegisterFileDescriptor(self, file_descriptor):
+ """Registers the given file descriptor in the local database.
+
+ Args:
+ file_descriptor: a descriptor.FileDescriptor.
+
+ Returns:
+ The provided descriptor.
+ """
+ self.pool.AddFileDescriptor(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: A str, a protocol buffer symbol.
+
+ Returns:
+ A Python class corresponding to the symbol.
+
+ Raises:
+ KeyError: if the symbol could not be found.
+ """
+
+ return self._symbols[symbol]
+
+ 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.
+ """
+
+ return self.GetSymbol(descriptor.full_name)
+
+ def GetMessages(self, files):
+ """Gets all the messages from a specified file.
+
+ This will find and resolve dependencies, failing if they are not registered
+ in the symbol database.
+
+
+ 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.
+
+ Raises:
+ KeyError: if a file could not be found.
+ """
+
+ result = {}
+ for f in files:
+ result.update(self._symbols_by_file[f])
+ return result
+
+_DEFAULT = SymbolDatabase(pool=descriptor_pool.Default())
+
+
+def Default():
+ """Returns the default SymbolDatabase."""
+ return _DEFAULT