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+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc. All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# 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.
+
+"""Provides DescriptorPool to use as a container for proto2 descriptors.
+
+The DescriptorPool is used in conjection with a DescriptorDatabase to maintain
+a collection of protocol buffer descriptors for use when dynamically creating
+message types at runtime.
+
+For most applications protocol buffers should be used via modules generated by
+the protocol buffer compiler tool. This should only be used when the type of
+protocol buffers used in an application or library cannot be predetermined.
+
+Below is a straightforward example on how to use this class:
+
+ pool = DescriptorPool()
+ file_descriptor_protos = [ ... ]
+ for file_descriptor_proto in file_descriptor_protos:
+ pool.Add(file_descriptor_proto)
+ my_message_descriptor = pool.FindMessageTypeByName('some.package.MessageType')
+
+The message descriptor can be used in conjunction with the message_factory
+module in order to create a protocol buffer class that can be encoded and
+decoded.
+
+If you want to get a Python class for the specified proto, use the
+helper functions inside google.protobuf.message_factory
+directly instead of this class.
+"""
+
+__author__ = 'matthewtoia@google.com (Matt Toia)'
+
+import sys
+
+from google.protobuf import descriptor
+from google.protobuf import descriptor_database
+from google.protobuf import text_encoding
+
+
+def _NormalizeFullyQualifiedName(name):
+ """Remove leading period from fully-qualified type name.
+
+ Due to b/13860351 in descriptor_database.py, types in the root namespace are
+ generated with a leading period. This function removes that prefix.
+
+ Args:
+ name: A str, the fully-qualified symbol name.
+
+ Returns:
+ A str, the normalized fully-qualified symbol name.
+ """
+ return name.lstrip('.')
+
+
+class DescriptorPool(object):
+ """A collection of protobufs dynamically constructed by descriptor protos."""
+
+ def __init__(self, descriptor_db=None):
+ """Initializes a Pool of proto buffs.
+
+ The descriptor_db argument to the constructor is provided to allow
+ specialized file descriptor proto lookup code to be triggered on demand. An
+ example would be an implementation which will read and compile a file
+ specified in a call to FindFileByName() and not require the call to Add()
+ at all. Results from this database will be cached internally here as well.
+
+ Args:
+ descriptor_db: A secondary source of file descriptors.
+ """
+
+ self._internal_db = descriptor_database.DescriptorDatabase()
+ self._descriptor_db = descriptor_db
+ self._descriptors = {}
+ self._enum_descriptors = {}
+ self._file_descriptors = {}
+
+ def Add(self, file_desc_proto):
+ """Adds the FileDescriptorProto and its types to this pool.
+
+ Args:
+ file_desc_proto: The FileDescriptorProto to add.
+ """
+
+ self._internal_db.Add(file_desc_proto)
+
+ def AddDescriptor(self, desc):
+ """Adds a Descriptor to the pool, non-recursively.
+
+ If the Descriptor contains nested messages or enums, the caller must
+ explicitly register them. This method also registers the FileDescriptor
+ associated with the message.
+
+ Args:
+ desc: A Descriptor.
+ """
+ if not isinstance(desc, descriptor.Descriptor):
+ raise TypeError('Expected instance of descriptor.Descriptor.')
+
+ self._descriptors[desc.full_name] = desc
+ self.AddFileDescriptor(desc.file)
+
+ def AddEnumDescriptor(self, enum_desc):
+ """Adds an EnumDescriptor to the pool.
+
+ This method also registers the FileDescriptor associated with the message.
+
+ Args:
+ enum_desc: An EnumDescriptor.
+ """
+
+ if not isinstance(enum_desc, descriptor.EnumDescriptor):
+ raise TypeError('Expected instance of descriptor.EnumDescriptor.')
+
+ self._enum_descriptors[enum_desc.full_name] = enum_desc
+ self.AddFileDescriptor(enum_desc.file)
+
+ def AddFileDescriptor(self, file_desc):
+ """Adds a FileDescriptor to the pool, non-recursively.
+
+ If the FileDescriptor contains messages or enums, the caller must explicitly
+ register them.
+
+ Args:
+ file_desc: A FileDescriptor.
+ """
+
+ if not isinstance(file_desc, descriptor.FileDescriptor):
+ raise TypeError('Expected instance of descriptor.FileDescriptor.')
+ self._file_descriptors[file_desc.name] = file_desc
+
+ def FindFileByName(self, file_name):
+ """Gets a FileDescriptor by file name.
+
+ Args:
+ file_name: The path to the file to get a descriptor for.
+
+ Returns:
+ A FileDescriptor for the named file.
+
+ Raises:
+ KeyError: if the file can not be found in the pool.
+ """
+
+ try:
+ return self._file_descriptors[file_name]
+ except KeyError:
+ pass
+
+ try:
+ file_proto = self._internal_db.FindFileByName(file_name)
+ except KeyError:
+ _, error, _ = sys.exc_info() #PY25 compatible for GAE.
+ if self._descriptor_db:
+ file_proto = self._descriptor_db.FindFileByName(file_name)
+ else:
+ raise error
+ if not file_proto:
+ raise KeyError('Cannot find a file named %s' % file_name)
+ return self._ConvertFileProtoToFileDescriptor(file_proto)
+
+ def FindFileContainingSymbol(self, symbol):
+ """Gets the FileDescriptor for the file containing the specified symbol.
+
+ Args:
+ symbol: The name of the symbol to search for.
+
+ Returns:
+ A FileDescriptor that contains the specified symbol.
+
+ Raises:
+ KeyError: if the file can not be found in the pool.
+ """
+
+ symbol = _NormalizeFullyQualifiedName(symbol)
+ try:
+ return self._descriptors[symbol].file
+ except KeyError:
+ pass
+
+ try:
+ return self._enum_descriptors[symbol].file
+ except KeyError:
+ pass
+
+ try:
+ file_proto = self._internal_db.FindFileContainingSymbol(symbol)
+ except KeyError:
+ _, error, _ = sys.exc_info() #PY25 compatible for GAE.
+ if self._descriptor_db:
+ file_proto = self._descriptor_db.FindFileContainingSymbol(symbol)
+ else:
+ raise error
+ if not file_proto:
+ raise KeyError('Cannot find a file containing %s' % symbol)
+ return self._ConvertFileProtoToFileDescriptor(file_proto)
+
+ def FindMessageTypeByName(self, full_name):
+ """Loads the named descriptor from the pool.
+
+ Args:
+ full_name: The full name of the descriptor to load.
+
+ Returns:
+ The descriptor for the named type.
+ """
+
+ full_name = _NormalizeFullyQualifiedName(full_name)
+ if full_name not in self._descriptors:
+ self.FindFileContainingSymbol(full_name)
+ return self._descriptors[full_name]
+
+ def FindEnumTypeByName(self, full_name):
+ """Loads the named enum descriptor from the pool.
+
+ Args:
+ full_name: The full name of the enum descriptor to load.
+
+ Returns:
+ The enum descriptor for the named type.
+ """
+
+ full_name = _NormalizeFullyQualifiedName(full_name)
+ if full_name not in self._enum_descriptors:
+ self.FindFileContainingSymbol(full_name)
+ return self._enum_descriptors[full_name]
+
+ def _ConvertFileProtoToFileDescriptor(self, file_proto):
+ """Creates a FileDescriptor from a proto or returns a cached copy.
+
+ This method also has the side effect of loading all the symbols found in
+ the file into the appropriate dictionaries in the pool.
+
+ Args:
+ file_proto: The proto to convert.
+
+ Returns:
+ A FileDescriptor matching the passed in proto.
+ """
+
+ if file_proto.name not in self._file_descriptors:
+ built_deps = list(self._GetDeps(file_proto.dependency))
+ direct_deps = [self.FindFileByName(n) for n in file_proto.dependency]
+
+ file_descriptor = descriptor.FileDescriptor(
+ name=file_proto.name,
+ package=file_proto.package,
+ options=file_proto.options,
+ serialized_pb=file_proto.SerializeToString(),
+ dependencies=direct_deps)
+ scope = {}
+
+ # This loop extracts all the message and enum types from all the
+ # dependencoes of the file_proto. This is necessary to create the
+ # scope of available message types when defining the passed in
+ # file proto.
+ for dependency in built_deps:
+ scope.update(self._ExtractSymbols(
+ dependency.message_types_by_name.values()))
+ scope.update((_PrefixWithDot(enum.full_name), enum)
+ for enum in dependency.enum_types_by_name.values())
+
+ for message_type in file_proto.message_type:
+ message_desc = self._ConvertMessageDescriptor(
+ message_type, file_proto.package, file_descriptor, scope)
+ file_descriptor.message_types_by_name[message_desc.name] = message_desc
+
+ for enum_type in file_proto.enum_type:
+ file_descriptor.enum_types_by_name[enum_type.name] = (
+ self._ConvertEnumDescriptor(enum_type, file_proto.package,
+ file_descriptor, None, scope))
+
+ for index, extension_proto in enumerate(file_proto.extension):
+ extension_desc = self.MakeFieldDescriptor(
+ extension_proto, file_proto.package, index, is_extension=True)
+ extension_desc.containing_type = self._GetTypeFromScope(
+ file_descriptor.package, extension_proto.extendee, scope)
+ self.SetFieldType(extension_proto, extension_desc,
+ file_descriptor.package, scope)
+ file_descriptor.extensions_by_name[extension_desc.name] = extension_desc
+
+ for desc_proto in file_proto.message_type:
+ self.SetAllFieldTypes(file_proto.package, desc_proto, scope)
+
+ if file_proto.package:
+ desc_proto_prefix = _PrefixWithDot(file_proto.package)
+ else:
+ desc_proto_prefix = ''
+
+ for desc_proto in file_proto.message_type:
+ desc = self._GetTypeFromScope(desc_proto_prefix, desc_proto.name, scope)
+ file_descriptor.message_types_by_name[desc_proto.name] = desc
+ self.Add(file_proto)
+ self._file_descriptors[file_proto.name] = file_descriptor
+
+ return self._file_descriptors[file_proto.name]
+
+ def _ConvertMessageDescriptor(self, desc_proto, package=None, file_desc=None,
+ scope=None):
+ """Adds the proto to the pool in the specified package.
+
+ Args:
+ desc_proto: The descriptor_pb2.DescriptorProto protobuf message.
+ package: The package the proto should be located in.
+ file_desc: The file containing this message.
+ scope: Dict mapping short and full symbols to message and enum types.
+
+ Returns:
+ The added descriptor.
+ """
+
+ if package:
+ desc_name = '.'.join((package, desc_proto.name))
+ else:
+ desc_name = desc_proto.name
+
+ if file_desc is None:
+ file_name = None
+ else:
+ file_name = file_desc.name
+
+ if scope is None:
+ scope = {}
+
+ nested = [
+ self._ConvertMessageDescriptor(nested, desc_name, file_desc, scope)
+ for nested in desc_proto.nested_type]
+ enums = [
+ self._ConvertEnumDescriptor(enum, desc_name, file_desc, None, scope)
+ for enum in desc_proto.enum_type]
+ fields = [self.MakeFieldDescriptor(field, desc_name, index)
+ for index, field in enumerate(desc_proto.field)]
+ extensions = [
+ self.MakeFieldDescriptor(extension, desc_name, index, is_extension=True)
+ for index, extension in enumerate(desc_proto.extension)]
+ oneofs = [
+ descriptor.OneofDescriptor(desc.name, '.'.join((desc_name, desc.name)),
+ index, None, [])
+ for index, desc in enumerate(desc_proto.oneof_decl)]
+ extension_ranges = [(r.start, r.end) for r in desc_proto.extension_range]
+ if extension_ranges:
+ is_extendable = True
+ else:
+ is_extendable = False
+ desc = descriptor.Descriptor(
+ name=desc_proto.name,
+ full_name=desc_name,
+ filename=file_name,
+ containing_type=None,
+ fields=fields,
+ oneofs=oneofs,
+ nested_types=nested,
+ enum_types=enums,
+ extensions=extensions,
+ options=desc_proto.options,
+ is_extendable=is_extendable,
+ extension_ranges=extension_ranges,
+ file=file_desc,
+ serialized_start=None,
+ serialized_end=None)
+ for nested in desc.nested_types:
+ nested.containing_type = desc
+ for enum in desc.enum_types:
+ enum.containing_type = desc
+ for field_index, field_desc in enumerate(desc_proto.field):
+ if field_desc.HasField('oneof_index'):
+ oneof_index = field_desc.oneof_index
+ oneofs[oneof_index].fields.append(fields[field_index])
+ fields[field_index].containing_oneof = oneofs[oneof_index]
+
+ scope[_PrefixWithDot(desc_name)] = desc
+ self._descriptors[desc_name] = desc
+ return desc
+
+ def _ConvertEnumDescriptor(self, enum_proto, package=None, file_desc=None,
+ containing_type=None, scope=None):
+ """Make a protobuf EnumDescriptor given an EnumDescriptorProto protobuf.
+
+ Args:
+ enum_proto: The descriptor_pb2.EnumDescriptorProto protobuf message.
+ package: Optional package name for the new message EnumDescriptor.
+ file_desc: The file containing the enum descriptor.
+ containing_type: The type containing this enum.
+ scope: Scope containing available types.
+
+ Returns:
+ The added descriptor
+ """
+
+ if package:
+ enum_name = '.'.join((package, enum_proto.name))
+ else:
+ enum_name = enum_proto.name
+
+ if file_desc is None:
+ file_name = None
+ else:
+ file_name = file_desc.name
+
+ values = [self._MakeEnumValueDescriptor(value, index)
+ for index, value in enumerate(enum_proto.value)]
+ desc = descriptor.EnumDescriptor(name=enum_proto.name,
+ full_name=enum_name,
+ filename=file_name,
+ file=file_desc,
+ values=values,
+ containing_type=containing_type,
+ options=enum_proto.options)
+ scope['.%s' % enum_name] = desc
+ self._enum_descriptors[enum_name] = desc
+ return desc
+
+ def MakeFieldDescriptor(self, field_proto, message_name, index,
+ is_extension=False):
+ """Creates a field descriptor from a FieldDescriptorProto.
+
+ For message and enum type fields, this method will do a look up
+ in the pool for the appropriate descriptor for that type. If it
+ is unavailable, it will fall back to the _source function to
+ create it. If this type is still unavailable, construction will
+ fail.
+
+ Args:
+ field_proto: The proto describing the field.
+ message_name: The name of the containing message.
+ index: Index of the field
+ is_extension: Indication that this field is for an extension.
+
+ Returns:
+ An initialized FieldDescriptor object
+ """
+
+ if message_name:
+ full_name = '.'.join((message_name, field_proto.name))
+ else:
+ full_name = field_proto.name
+
+ return descriptor.FieldDescriptor(
+ name=field_proto.name,
+ full_name=full_name,
+ index=index,
+ number=field_proto.number,
+ type=field_proto.type,
+ cpp_type=None,
+ message_type=None,
+ enum_type=None,
+ containing_type=None,
+ label=field_proto.label,
+ has_default_value=False,
+ default_value=None,
+ is_extension=is_extension,
+ extension_scope=None,
+ options=field_proto.options)
+
+ def SetAllFieldTypes(self, package, desc_proto, scope):
+ """Sets all the descriptor's fields's types.
+
+ This method also sets the containing types on any extensions.
+
+ Args:
+ package: The current package of desc_proto.
+ desc_proto: The message descriptor to update.
+ scope: Enclosing scope of available types.
+ """
+
+ package = _PrefixWithDot(package)
+
+ main_desc = self._GetTypeFromScope(package, desc_proto.name, scope)
+
+ if package == '.':
+ nested_package = _PrefixWithDot(desc_proto.name)
+ else:
+ nested_package = '.'.join([package, desc_proto.name])
+
+ for field_proto, field_desc in zip(desc_proto.field, main_desc.fields):
+ self.SetFieldType(field_proto, field_desc, nested_package, scope)
+
+ for extension_proto, extension_desc in (
+ zip(desc_proto.extension, main_desc.extensions)):
+ extension_desc.containing_type = self._GetTypeFromScope(
+ nested_package, extension_proto.extendee, scope)
+ self.SetFieldType(extension_proto, extension_desc, nested_package, scope)
+
+ for nested_type in desc_proto.nested_type:
+ self.SetAllFieldTypes(nested_package, nested_type, scope)
+
+ def SetFieldType(self, field_proto, field_desc, package, scope):
+ """Sets the field's type, cpp_type, message_type and enum_type.
+
+ Args:
+ field_proto: Data about the field in proto format.
+ field_desc: The descriptor to modiy.
+ package: The package the field's container is in.
+ scope: Enclosing scope of available types.
+ """
+ if field_proto.type_name:
+ desc = self._GetTypeFromScope(package, field_proto.type_name, scope)
+ else:
+ desc = None
+
+ if not field_proto.HasField('type'):
+ if isinstance(desc, descriptor.Descriptor):
+ field_proto.type = descriptor.FieldDescriptor.TYPE_MESSAGE
+ else:
+ field_proto.type = descriptor.FieldDescriptor.TYPE_ENUM
+
+ field_desc.cpp_type = descriptor.FieldDescriptor.ProtoTypeToCppProtoType(
+ field_proto.type)
+
+ if (field_proto.type == descriptor.FieldDescriptor.TYPE_MESSAGE
+ or field_proto.type == descriptor.FieldDescriptor.TYPE_GROUP):
+ field_desc.message_type = desc
+
+ if field_proto.type == descriptor.FieldDescriptor.TYPE_ENUM:
+ field_desc.enum_type = desc
+
+ if field_proto.label == descriptor.FieldDescriptor.LABEL_REPEATED:
+ field_desc.has_default_value = False
+ field_desc.default_value = []
+ elif field_proto.HasField('default_value'):
+ field_desc.has_default_value = True
+ if (field_proto.type == descriptor.FieldDescriptor.TYPE_DOUBLE or
+ field_proto.type == descriptor.FieldDescriptor.TYPE_FLOAT):
+ field_desc.default_value = float(field_proto.default_value)
+ elif field_proto.type == descriptor.FieldDescriptor.TYPE_STRING:
+ field_desc.default_value = field_proto.default_value
+ elif field_proto.type == descriptor.FieldDescriptor.TYPE_BOOL:
+ field_desc.default_value = field_proto.default_value.lower() == 'true'
+ elif field_proto.type == descriptor.FieldDescriptor.TYPE_ENUM:
+ field_desc.default_value = field_desc.enum_type.values_by_name[
+ field_proto.default_value].index
+ elif field_proto.type == descriptor.FieldDescriptor.TYPE_BYTES:
+ field_desc.default_value = text_encoding.CUnescape(
+ field_proto.default_value)
+ else:
+ field_desc.default_value = int(field_proto.default_value)
+ else:
+ field_desc.has_default_value = False
+ field_desc.default_value = None
+
+ field_desc.type = field_proto.type
+
+ def _MakeEnumValueDescriptor(self, value_proto, index):
+ """Creates a enum value descriptor object from a enum value proto.
+
+ Args:
+ value_proto: The proto describing the enum value.
+ index: The index of the enum value.
+
+ Returns:
+ An initialized EnumValueDescriptor object.
+ """
+
+ return descriptor.EnumValueDescriptor(
+ name=value_proto.name,
+ index=index,
+ number=value_proto.number,
+ options=value_proto.options,
+ type=None)
+
+ def _ExtractSymbols(self, descriptors):
+ """Pulls out all the symbols from descriptor protos.
+
+ Args:
+ descriptors: The messages to extract descriptors from.
+ Yields:
+ A two element tuple of the type name and descriptor object.
+ """
+
+ for desc in descriptors:
+ yield (_PrefixWithDot(desc.full_name), desc)
+ for symbol in self._ExtractSymbols(desc.nested_types):
+ yield symbol
+ for enum in desc.enum_types:
+ yield (_PrefixWithDot(enum.full_name), enum)
+
+ def _GetDeps(self, dependencies):
+ """Recursively finds dependencies for file protos.
+
+ Args:
+ dependencies: The names of the files being depended on.
+
+ Yields:
+ Each direct and indirect dependency.
+ """
+
+ for dependency in dependencies:
+ dep_desc = self.FindFileByName(dependency)
+ yield dep_desc
+ for parent_dep in dep_desc.dependencies:
+ yield parent_dep
+
+ def _GetTypeFromScope(self, package, type_name, scope):
+ """Finds a given type name in the current scope.
+
+ Args:
+ package: The package the proto should be located in.
+ type_name: The name of the type to be found in the scope.
+ scope: Dict mapping short and full symbols to message and enum types.
+
+ Returns:
+ The descriptor for the requested type.
+ """
+ if type_name not in scope:
+ components = _PrefixWithDot(package).split('.')
+ while components:
+ possible_match = '.'.join(components + [type_name])
+ if possible_match in scope:
+ type_name = possible_match
+ break
+ else:
+ components.pop(-1)
+ return scope[type_name]
+
+
+def _PrefixWithDot(name):
+ return name if name.startswith('.') else '.%s' % name