| #!/usr/bin/env python |
| # |
| # Copyright 2007 Google Inc. |
| # |
| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| # |
| |
| |
| """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.net.proto2.python.public.message_factory |
| directly instead of this class. |
| """ |
| |
| |
| import sys |
| |
| from google.net.proto2.python.public import descriptor |
| from google.net.proto2.python.public import descriptor_database |
| from google.net.proto2.python.public 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() |
| 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() |
| 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 = {} |
| |
| |
| |
| |
| |
| 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].number |
| 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 |
