diff options
Diffstat (limited to 'python/google/protobuf/reflection.py')
| -rwxr-xr-x | python/google/protobuf/reflection.py | 1071 |
1 files changed, 64 insertions, 1007 deletions
diff --git a/python/google/protobuf/reflection.py b/python/google/protobuf/reflection.py index 5b23803..1fc704a 100755 --- a/python/google/protobuf/reflection.py +++ b/python/google/protobuf/reflection.py @@ -1,6 +1,6 @@ # Protocol Buffers - Google's data interchange format # Copyright 2008 Google Inc. All rights reserved. -# http://code.google.com/p/protobuf/ +# 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 @@ -29,9 +29,6 @@ # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. # This code is meant to work on Python 2.4 and above only. -# -# TODO(robinson): Helpers for verbose, common checks like seeing if a -# descriptor's cpp_type is CPPTYPE_MESSAGE. """Contains a metaclass and helper functions used to create protocol message classes from Descriptor objects at runtime. @@ -50,27 +47,29 @@ this file*. __author__ = 'robinson@google.com (Will Robinson)' -try: - from cStringIO import StringIO -except ImportError: - from StringIO import StringIO -import struct -import weakref -# We use "as" to avoid name collisions with variables. -from google.protobuf.internal import containers -from google.protobuf.internal import decoder -from google.protobuf.internal import encoder -from google.protobuf.internal import message_listener as message_listener_mod -from google.protobuf.internal import type_checkers -from google.protobuf.internal import wire_format +from google.protobuf.internal import api_implementation from google.protobuf import descriptor as descriptor_mod -from google.protobuf import message as message_mod -from google.protobuf import text_format +from google.protobuf import message _FieldDescriptor = descriptor_mod.FieldDescriptor +if api_implementation.Type() == 'cpp': + if api_implementation.Version() == 2: + from google.protobuf.pyext import cpp_message + _NewMessage = cpp_message.NewMessage + _InitMessage = cpp_message.InitMessage + else: + from google.protobuf.internal import cpp_message + _NewMessage = cpp_message.NewMessage + _InitMessage = cpp_message.InitMessage +else: + from google.protobuf.internal import python_message + _NewMessage = python_message.NewMessage + _InitMessage = python_message.InitMessage + + class GeneratedProtocolMessageType(type): """Metaclass for protocol message classes created at runtime from Descriptors. @@ -92,6 +91,10 @@ class GeneratedProtocolMessageType(type): myproto_instance = MyProtoClass() myproto.foo_field = 23 ... + + The above example will not work for nested types. If you wish to include them, + use reflection.MakeClass() instead of manually instantiating the class in + order to create the appropriate class structure. """ # Must be consistent with the protocol-compiler code in @@ -120,10 +123,12 @@ class GeneratedProtocolMessageType(type): Newly-allocated class. """ descriptor = dictionary[GeneratedProtocolMessageType._DESCRIPTOR_KEY] - _AddSlots(descriptor, dictionary) - _AddClassAttributesForNestedExtensions(descriptor, dictionary) + bases = _NewMessage(bases, descriptor, dictionary) superclass = super(GeneratedProtocolMessageType, cls) - return superclass.__new__(cls, name, bases, dictionary) + + new_class = superclass.__new__(cls, name, bases, dictionary) + setattr(descriptor, '_concrete_class', new_class) + return new_class def __init__(cls, name, bases, dictionary): """Here we perform the majority of our work on the class. @@ -143,1006 +148,58 @@ class GeneratedProtocolMessageType(type): type. """ descriptor = dictionary[GeneratedProtocolMessageType._DESCRIPTOR_KEY] - - cls._decoders_by_tag = {} - cls._extensions_by_name = {} - cls._extensions_by_number = {} - if (descriptor.has_options and - descriptor.GetOptions().message_set_wire_format): - cls._decoders_by_tag[decoder.MESSAGE_SET_ITEM_TAG] = ( - decoder.MessageSetItemDecoder(cls._extensions_by_number)) - - # We act as a "friend" class of the descriptor, setting - # its _concrete_class attribute the first time we use a - # given descriptor to initialize a concrete protocol message - # class. We also attach stuff to each FieldDescriptor for quick - # lookup later on. - concrete_class_attr_name = '_concrete_class' - if not hasattr(descriptor, concrete_class_attr_name): - setattr(descriptor, concrete_class_attr_name, cls) - for field in descriptor.fields: - _AttachFieldHelpers(cls, field) - - _AddEnumValues(descriptor, cls) - _AddInitMethod(descriptor, cls) - _AddPropertiesForFields(descriptor, cls) - _AddPropertiesForExtensions(descriptor, cls) - _AddStaticMethods(cls) - _AddMessageMethods(descriptor, cls) - _AddPrivateHelperMethods(cls) + _InitMessage(descriptor, cls) superclass = super(GeneratedProtocolMessageType, cls) superclass.__init__(name, bases, dictionary) -# Stateless helpers for GeneratedProtocolMessageType below. -# Outside clients should not access these directly. -# -# I opted not to make any of these methods on the metaclass, to make it more -# clear that I'm not really using any state there and to keep clients from -# thinking that they have direct access to these construction helpers. - - -def _PropertyName(proto_field_name): - """Returns the name of the public property attribute which - clients can use to get and (in some cases) set the value - of a protocol message field. - - Args: - proto_field_name: The protocol message field name, exactly - as it appears (or would appear) in a .proto file. - """ - # TODO(robinson): Escape Python keywords (e.g., yield), and test this support. - # nnorwitz makes my day by writing: - # """ - # FYI. See the keyword module in the stdlib. This could be as simple as: - # - # if keyword.iskeyword(proto_field_name): - # return proto_field_name + "_" - # return proto_field_name - # """ - # Kenton says: The above is a BAD IDEA. People rely on being able to use - # getattr() and setattr() to reflectively manipulate field values. If we - # rename the properties, then every such user has to also make sure to apply - # the same transformation. Note that currently if you name a field "yield", - # you can still access it just fine using getattr/setattr -- it's not even - # that cumbersome to do so. - # TODO(kenton): Remove this method entirely if/when everyone agrees with my - # position. - return proto_field_name - - -def _VerifyExtensionHandle(message, extension_handle): - """Verify that the given extension handle is valid.""" - - if not isinstance(extension_handle, _FieldDescriptor): - raise KeyError('HasExtension() expects an extension handle, got: %s' % - extension_handle) - - if not extension_handle.is_extension: - raise KeyError('"%s" is not an extension.' % extension_handle.full_name) - - if extension_handle.containing_type is not message.DESCRIPTOR: - raise KeyError('Extension "%s" extends message type "%s", but this ' - 'message is of type "%s".' % - (extension_handle.full_name, - extension_handle.containing_type.full_name, - message.DESCRIPTOR.full_name)) - - -def _AddSlots(message_descriptor, dictionary): - """Adds a __slots__ entry to dictionary, containing the names of all valid - attributes for this message type. - - Args: - message_descriptor: A Descriptor instance describing this message type. - dictionary: Class dictionary to which we'll add a '__slots__' entry. - """ - dictionary['__slots__'] = ['_cached_byte_size', - '_cached_byte_size_dirty', - '_fields', - '_is_present_in_parent', - '_listener', - '_listener_for_children', - '__weakref__'] - - -def _IsMessageSetExtension(field): - return (field.is_extension and - field.containing_type.has_options and - field.containing_type.GetOptions().message_set_wire_format and - field.type == _FieldDescriptor.TYPE_MESSAGE and - field.message_type == field.extension_scope and - field.label == _FieldDescriptor.LABEL_OPTIONAL) - - -def _AttachFieldHelpers(cls, field_descriptor): - is_repeated = (field_descriptor.label == _FieldDescriptor.LABEL_REPEATED) - is_packed = (field_descriptor.has_options and - field_descriptor.GetOptions().packed) - - if _IsMessageSetExtension(field_descriptor): - field_encoder = encoder.MessageSetItemEncoder(field_descriptor.number) - sizer = encoder.MessageSetItemSizer(field_descriptor.number) - else: - field_encoder = type_checkers.TYPE_TO_ENCODER[field_descriptor.type]( - field_descriptor.number, is_repeated, is_packed) - sizer = type_checkers.TYPE_TO_SIZER[field_descriptor.type]( - field_descriptor.number, is_repeated, is_packed) - - field_descriptor._encoder = field_encoder - field_descriptor._sizer = sizer - field_descriptor._default_constructor = _DefaultValueConstructorForField( - field_descriptor) - - def AddDecoder(wiretype, is_packed): - tag_bytes = encoder.TagBytes(field_descriptor.number, wiretype) - cls._decoders_by_tag[tag_bytes] = ( - type_checkers.TYPE_TO_DECODER[field_descriptor.type]( - field_descriptor.number, is_repeated, is_packed, - field_descriptor, field_descriptor._default_constructor)) - - AddDecoder(type_checkers.FIELD_TYPE_TO_WIRE_TYPE[field_descriptor.type], - False) - - if is_repeated and wire_format.IsTypePackable(field_descriptor.type): - # To support wire compatibility of adding packed = true, add a decoder for - # packed values regardless of the field's options. - AddDecoder(wire_format.WIRETYPE_LENGTH_DELIMITED, True) - - -def _AddClassAttributesForNestedExtensions(descriptor, dictionary): - extension_dict = descriptor.extensions_by_name - for extension_name, extension_field in extension_dict.iteritems(): - assert extension_name not in dictionary - dictionary[extension_name] = extension_field - - -def _AddEnumValues(descriptor, cls): - """Sets class-level attributes for all enum fields defined in this message. - - Args: - descriptor: Descriptor object for this message type. - cls: Class we're constructing for this message type. - """ - for enum_type in descriptor.enum_types: - for enum_value in enum_type.values: - setattr(cls, enum_value.name, enum_value.number) - - -def _DefaultValueConstructorForField(field): - """Returns a function which returns a default value for a field. +def ParseMessage(descriptor, byte_str): + """Generate a new Message instance from this Descriptor and a byte string. Args: - field: FieldDescriptor object for this field. + descriptor: Protobuf Descriptor object + byte_str: Serialized protocol buffer byte string - The returned function has one argument: - message: Message instance containing this field, or a weakref proxy - of same. - - That function in turn returns a default value for this field. The default - value may refer back to |message| via a weak reference. - """ - - if field.label == _FieldDescriptor.LABEL_REPEATED: - if field.default_value != []: - raise ValueError('Repeated field default value not empty list: %s' % ( - field.default_value)) - if field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: - # We can't look at _concrete_class yet since it might not have - # been set. (Depends on order in which we initialize the classes). - message_type = field.message_type - def MakeRepeatedMessageDefault(message): - return containers.RepeatedCompositeFieldContainer( - message._listener_for_children, field.message_type) - return MakeRepeatedMessageDefault - else: - type_checker = type_checkers.GetTypeChecker(field.cpp_type, field.type) - def MakeRepeatedScalarDefault(message): - return containers.RepeatedScalarFieldContainer( - message._listener_for_children, type_checker) - return MakeRepeatedScalarDefault - - if field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: - # _concrete_class may not yet be initialized. - message_type = field.message_type - def MakeSubMessageDefault(message): - result = message_type._concrete_class() - result._SetListener(message._listener_for_children) - return result - return MakeSubMessageDefault - - def MakeScalarDefault(message): - return field.default_value - return MakeScalarDefault - - -def _AddInitMethod(message_descriptor, cls): - """Adds an __init__ method to cls.""" - fields = message_descriptor.fields - def init(self, **kwargs): - self._cached_byte_size = 0 - self._cached_byte_size_dirty = False - self._fields = {} - self._is_present_in_parent = False - self._listener = message_listener_mod.NullMessageListener() - self._listener_for_children = _Listener(self) - for field_name, field_value in kwargs.iteritems(): - field = _GetFieldByName(message_descriptor, field_name) - if field is None: - raise TypeError("%s() got an unexpected keyword argument '%s'" % - (message_descriptor.name, field_name)) - if field.label == _FieldDescriptor.LABEL_REPEATED: - copy = field._default_constructor(self) - if field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: # Composite - for val in field_value: - copy.add().MergeFrom(val) - else: # Scalar - copy.extend(field_value) - self._fields[field] = copy - elif field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: - copy = field._default_constructor(self) - copy.MergeFrom(field_value) - self._fields[field] = copy - else: - self._fields[field] = field_value - - init.__module__ = None - init.__doc__ = None - cls.__init__ = init - - -def _GetFieldByName(message_descriptor, field_name): - """Returns a field descriptor by field name. - - Args: - message_descriptor: A Descriptor describing all fields in message. - field_name: The name of the field to retrieve. Returns: - The field descriptor associated with the field name. - """ - try: - return message_descriptor.fields_by_name[field_name] - except KeyError: - raise ValueError('Protocol message has no "%s" field.' % field_name) - - -def _AddPropertiesForFields(descriptor, cls): - """Adds properties for all fields in this protocol message type.""" - for field in descriptor.fields: - _AddPropertiesForField(field, cls) - - if descriptor.is_extendable: - # _ExtensionDict is just an adaptor with no state so we allocate a new one - # every time it is accessed. - cls.Extensions = property(lambda self: _ExtensionDict(self)) - - -def _AddPropertiesForField(field, cls): - """Adds a public property for a protocol message field. - Clients can use this property to get and (in the case - of non-repeated scalar fields) directly set the value - of a protocol message field. - - Args: - field: A FieldDescriptor for this field. - cls: The class we're constructing. - """ - # Catch it if we add other types that we should - # handle specially here. - assert _FieldDescriptor.MAX_CPPTYPE == 10 - - constant_name = field.name.upper() + "_FIELD_NUMBER" - setattr(cls, constant_name, field.number) - - if field.label == _FieldDescriptor.LABEL_REPEATED: - _AddPropertiesForRepeatedField(field, cls) - elif field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: - _AddPropertiesForNonRepeatedCompositeField(field, cls) - else: - _AddPropertiesForNonRepeatedScalarField(field, cls) - - -def _AddPropertiesForRepeatedField(field, cls): - """Adds a public property for a "repeated" protocol message field. Clients - can use this property to get the value of the field, which will be either a - _RepeatedScalarFieldContainer or _RepeatedCompositeFieldContainer (see - below). - - Note that when clients add values to these containers, we perform - type-checking in the case of repeated scalar fields, and we also set any - necessary "has" bits as a side-effect. - - Args: - field: A FieldDescriptor for this field. - cls: The class we're constructing. - """ - proto_field_name = field.name - property_name = _PropertyName(proto_field_name) - - def getter(self): - field_value = self._fields.get(field) - if field_value is None: - # Construct a new object to represent this field. - field_value = field._default_constructor(self) - - # Atomically check if another thread has preempted us and, if not, swap - # in the new object we just created. If someone has preempted us, we - # take that object and discard ours. - # WARNING: We are relying on setdefault() being atomic. This is true - # in CPython but we haven't investigated others. This warning appears - # in several other locations in this file. - field_value = self._fields.setdefault(field, field_value) - return field_value - getter.__module__ = None - getter.__doc__ = 'Getter for %s.' % proto_field_name - - # We define a setter just so we can throw an exception with a more - # helpful error message. - def setter(self, new_value): - raise AttributeError('Assignment not allowed to repeated field ' - '"%s" in protocol message object.' % proto_field_name) - - doc = 'Magic attribute generated for "%s" proto field.' % proto_field_name - setattr(cls, property_name, property(getter, setter, doc=doc)) - - -def _AddPropertiesForNonRepeatedScalarField(field, cls): - """Adds a public property for a nonrepeated, scalar protocol message field. - Clients can use this property to get and directly set the value of the field. - Note that when the client sets the value of a field by using this property, - all necessary "has" bits are set as a side-effect, and we also perform - type-checking. - - Args: - field: A FieldDescriptor for this field. - cls: The class we're constructing. - """ - proto_field_name = field.name - property_name = _PropertyName(proto_field_name) - type_checker = type_checkers.GetTypeChecker(field.cpp_type, field.type) - default_value = field.default_value - - def getter(self): - return self._fields.get(field, default_value) - getter.__module__ = None - getter.__doc__ = 'Getter for %s.' % proto_field_name - def setter(self, new_value): - type_checker.CheckValue(new_value) - self._fields[field] = new_value - # Check _cached_byte_size_dirty inline to improve performance, since scalar - # setters are called frequently. - if not self._cached_byte_size_dirty: - self._Modified() - setter.__module__ = None - setter.__doc__ = 'Setter for %s.' % proto_field_name - - # Add a property to encapsulate the getter/setter. - doc = 'Magic attribute generated for "%s" proto field.' % proto_field_name - setattr(cls, property_name, property(getter, setter, doc=doc)) - - -def _AddPropertiesForNonRepeatedCompositeField(field, cls): - """Adds a public property for a nonrepeated, composite protocol message field. - A composite field is a "group" or "message" field. - - Clients can use this property to get the value of the field, but cannot - assign to the property directly. - - Args: - field: A FieldDescriptor for this field. - cls: The class we're constructing. + Newly created protobuf Message object. """ - # TODO(robinson): Remove duplication with similar method - # for non-repeated scalars. - proto_field_name = field.name - property_name = _PropertyName(proto_field_name) - message_type = field.message_type - - def getter(self): - field_value = self._fields.get(field) - if field_value is None: - # Construct a new object to represent this field. - field_value = message_type._concrete_class() - field_value._SetListener(self._listener_for_children) - - # Atomically check if another thread has preempted us and, if not, swap - # in the new object we just created. If someone has preempted us, we - # take that object and discard ours. - # WARNING: We are relying on setdefault() being atomic. This is true - # in CPython but we haven't investigated others. This warning appears - # in several other locations in this file. - field_value = self._fields.setdefault(field, field_value) - return field_value - getter.__module__ = None - getter.__doc__ = 'Getter for %s.' % proto_field_name - - # We define a setter just so we can throw an exception with a more - # helpful error message. - def setter(self, new_value): - raise AttributeError('Assignment not allowed to composite field ' - '"%s" in protocol message object.' % proto_field_name) - - # Add a property to encapsulate the getter. - doc = 'Magic attribute generated for "%s" proto field.' % proto_field_name - setattr(cls, property_name, property(getter, setter, doc=doc)) - - -def _AddPropertiesForExtensions(descriptor, cls): - """Adds properties for all fields in this protocol message type.""" - extension_dict = descriptor.extensions_by_name - for extension_name, extension_field in extension_dict.iteritems(): - constant_name = extension_name.upper() + "_FIELD_NUMBER" - setattr(cls, constant_name, extension_field.number) - - -def _AddStaticMethods(cls): - # TODO(robinson): This probably needs to be thread-safe(?) - def RegisterExtension(extension_handle): - extension_handle.containing_type = cls.DESCRIPTOR - _AttachFieldHelpers(cls, extension_handle) - - # Try to insert our extension, failing if an extension with the same number - # already exists. - actual_handle = cls._extensions_by_number.setdefault( - extension_handle.number, extension_handle) - if actual_handle is not extension_handle: - raise AssertionError( - 'Extensions "%s" and "%s" both try to extend message type "%s" with ' - 'field number %d.' % - (extension_handle.full_name, actual_handle.full_name, - cls.DESCRIPTOR.full_name, extension_handle.number)) - - cls._extensions_by_name[extension_handle.full_name] = extension_handle - - handle = extension_handle # avoid line wrapping - if _IsMessageSetExtension(handle): - # MessageSet extension. Also register under type name. - cls._extensions_by_name[ - extension_handle.message_type.full_name] = extension_handle - - cls.RegisterExtension = staticmethod(RegisterExtension) - - def FromString(s): - message = cls() - message.MergeFromString(s) - return message - cls.FromString = staticmethod(FromString) - - -def _IsPresent(item): - """Given a (FieldDescriptor, value) tuple from _fields, return true if the - value should be included in the list returned by ListFields().""" - - if item[0].label == _FieldDescriptor.LABEL_REPEATED: - return bool(item[1]) - elif item[0].cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: - return item[1]._is_present_in_parent - else: - return True - - -def _AddListFieldsMethod(message_descriptor, cls): - """Helper for _AddMessageMethods().""" - - def ListFields(self): - all_fields = [item for item in self._fields.iteritems() if _IsPresent(item)] - all_fields.sort(key = lambda item: item[0].number) - return all_fields - - cls.ListFields = ListFields - - -def _AddHasFieldMethod(message_descriptor, cls): - """Helper for _AddMessageMethods().""" - - singular_fields = {} - for field in message_descriptor.fields: - if field.label != _FieldDescriptor.LABEL_REPEATED: - singular_fields[field.name] = field - - def HasField(self, field_name): - try: - field = singular_fields[field_name] - except KeyError: - raise ValueError( - 'Protocol message has no singular "%s" field.' % field_name) - - if field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: - value = self._fields.get(field) - return value is not None and value._is_present_in_parent - else: - return field in self._fields - cls.HasField = HasField + result_class = MakeClass(descriptor) + new_msg = result_class() + new_msg.ParseFromString(byte_str) + return new_msg -def _AddClearFieldMethod(message_descriptor, cls): - """Helper for _AddMessageMethods().""" - def ClearField(self, field_name): - try: - field = message_descriptor.fields_by_name[field_name] - except KeyError: - raise ValueError('Protocol message has no "%s" field.' % field_name) +def MakeClass(descriptor): + """Construct a class object for a protobuf described by descriptor. - if field in self._fields: - # Note: If the field is a sub-message, its listener will still point - # at us. That's fine, because the worst than can happen is that it - # will call _Modified() and invalidate our byte size. Big deal. - del self._fields[field] + Composite descriptors are handled by defining the new class as a member of the + parent class, recursing as deep as necessary. + This is the dynamic equivalent to: - # Always call _Modified() -- even if nothing was changed, this is - # a mutating method, and thus calling it should cause the field to become - # present in the parent message. - self._Modified() - - cls.ClearField = ClearField - - -def _AddClearExtensionMethod(cls): - """Helper for _AddMessageMethods().""" - def ClearExtension(self, extension_handle): - _VerifyExtensionHandle(self, extension_handle) - - # Similar to ClearField(), above. - if extension_handle in self._fields: - del self._fields[extension_handle] - self._Modified() - cls.ClearExtension = ClearExtension - - -def _AddClearMethod(message_descriptor, cls): - """Helper for _AddMessageMethods().""" - def Clear(self): - # Clear fields. - self._fields = {} - self._Modified() - cls.Clear = Clear - - -def _AddHasExtensionMethod(cls): - """Helper for _AddMessageMethods().""" - def HasExtension(self, extension_handle): - _VerifyExtensionHandle(self, extension_handle) - if extension_handle.label == _FieldDescriptor.LABEL_REPEATED: - raise KeyError('"%s" is repeated.' % extension_handle.full_name) - - if extension_handle.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: - value = self._fields.get(extension_handle) - return value is not None and value._is_present_in_parent - else: - return extension_handle in self._fields - cls.HasExtension = HasExtension - - -def _AddEqualsMethod(message_descriptor, cls): - """Helper for _AddMessageMethods().""" - def __eq__(self, other): - if (not isinstance(other, message_mod.Message) or - other.DESCRIPTOR != self.DESCRIPTOR): - return False - - if self is other: - return True - - return self.ListFields() == other.ListFields() - - cls.__eq__ = __eq__ - - -def _AddStrMethod(message_descriptor, cls): - """Helper for _AddMessageMethods().""" - def __str__(self): - return text_format.MessageToString(self) - cls.__str__ = __str__ - - -def _AddSetListenerMethod(cls): - """Helper for _AddMessageMethods().""" - def SetListener(self, listener): - if listener is None: - self._listener = message_listener_mod.NullMessageListener() - else: - self._listener = listener - cls._SetListener = SetListener - - -def _BytesForNonRepeatedElement(value, field_number, field_type): - """Returns the number of bytes needed to serialize a non-repeated element. - The returned byte count includes space for tag information and any - other additional space associated with serializing value. + class Parent(message.Message): + __metaclass__ = GeneratedProtocolMessageType + DESCRIPTOR = descriptor + class Child(message.Message): + __metaclass__ = GeneratedProtocolMessageType + DESCRIPTOR = descriptor.nested_types[0] + + Sample usage: + file_descriptor = descriptor_pb2.FileDescriptorProto() + file_descriptor.ParseFromString(proto2_string) + msg_descriptor = descriptor.MakeDescriptor(file_descriptor.message_type[0]) + msg_class = reflection.MakeClass(msg_descriptor) + msg = msg_class() Args: - value: Value we're serializing. - field_number: Field number of this value. (Since the field number - is stored as part of a varint-encoded tag, this has an impact - on the total bytes required to serialize the value). - field_type: The type of the field. One of the TYPE_* constants - within FieldDescriptor. - """ - try: - fn = type_checkers.TYPE_TO_BYTE_SIZE_FN[field_type] - return fn(field_number, value) - except KeyError: - raise message_mod.EncodeError('Unrecognized field type: %d' % field_type) - - -def _AddByteSizeMethod(message_descriptor, cls): - """Helper for _AddMessageMethods().""" - - def ByteSize(self): - if not self._cached_byte_size_dirty: - return self._cached_byte_size - - size = 0 - for field_descriptor, field_value in self.ListFields(): - size += field_descriptor._sizer(field_value) - - self._cached_byte_size = size - self._cached_byte_size_dirty = False - self._listener_for_children.dirty = False - return size - - cls.ByteSize = ByteSize - - -def _AddSerializeToStringMethod(message_descriptor, cls): - """Helper for _AddMessageMethods().""" - - def SerializeToString(self): - # Check if the message has all of its required fields set. - errors = [] - if not self.IsInitialized(): - raise message_mod.EncodeError( - 'Message is missing required fields: ' + - ','.join(self.FindInitializationErrors())) - return self.SerializePartialToString() - cls.SerializeToString = SerializeToString - - -def _AddSerializePartialToStringMethod(message_descriptor, cls): - """Helper for _AddMessageMethods().""" - - def SerializePartialToString(self): - out = StringIO() - self._InternalSerialize(out.write) - return out.getvalue() - cls.SerializePartialToString = SerializePartialToString - - def InternalSerialize(self, write_bytes): - for field_descriptor, field_value in self.ListFields(): - field_descriptor._encoder(write_bytes, field_value) - cls._InternalSerialize = InternalSerialize - - -def _AddMergeFromStringMethod(message_descriptor, cls): - """Helper for _AddMessageMethods().""" - def MergeFromString(self, serialized): - length = len(serialized) - try: - if self._InternalParse(serialized, 0, length) != length: - # The only reason _InternalParse would return early is if it - # encountered an end-group tag. - raise message_mod.DecodeError('Unexpected end-group tag.') - except IndexError: - raise message_mod.DecodeError('Truncated message.') - except struct.error, e: - raise message_mod.DecodeError(e) - return length # Return this for legacy reasons. - cls.MergeFromString = MergeFromString - - local_ReadTag = decoder.ReadTag - local_SkipField = decoder.SkipField - decoders_by_tag = cls._decoders_by_tag - - def InternalParse(self, buffer, pos, end): - self._Modified() - field_dict = self._fields - while pos != end: - (tag_bytes, new_pos) = local_ReadTag(buffer, pos) - field_decoder = decoders_by_tag.get(tag_bytes) - if field_decoder is None: - new_pos = local_SkipField(buffer, new_pos, end, tag_bytes) - if new_pos == -1: - return pos - pos = new_pos - else: - pos = field_decoder(buffer, new_pos, end, self, field_dict) - return pos - cls._InternalParse = InternalParse - - -def _AddIsInitializedMethod(message_descriptor, cls): - """Adds the IsInitialized and FindInitializationError methods to the - protocol message class.""" - - required_fields = [field for field in message_descriptor.fields - if field.label == _FieldDescriptor.LABEL_REQUIRED] - - def IsInitialized(self, errors=None): - """Checks if all required fields of a message are set. - - Args: - errors: A list which, if provided, will be populated with the field - paths of all missing required fields. - - Returns: - True iff the specified message has all required fields set. - """ - - # Performance is critical so we avoid HasField() and ListFields(). - - for field in required_fields: - if (field not in self._fields or - (field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE and - not self._fields[field]._is_present_in_parent)): - if errors is not None: - errors.extend(self.FindInitializationErrors()) - return False - - for field, value in self._fields.iteritems(): - if field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: - if field.label == _FieldDescriptor.LABEL_REPEATED: - for element in value: - if not element.IsInitialized(): - if errors is not None: - errors.extend(self.FindInitializationErrors()) - return False - elif value._is_present_in_parent and not value.IsInitialized(): - if errors is not None: - errors.extend(self.FindInitializationErrors()) - return False - - return True - - cls.IsInitialized = IsInitialized - - def FindInitializationErrors(self): - """Finds required fields which are not initialized. - - Returns: - A list of strings. Each string is a path to an uninitialized field from - the top-level message, e.g. "foo.bar[5].baz". - """ - - errors = [] # simplify things - - for field in required_fields: - if not self.HasField(field.name): - errors.append(field.name) - - for field, value in self.ListFields(): - if field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: - if field.is_extension: - name = "(%s)" % field.full_name - else: - name = field.name - - if field.label == _FieldDescriptor.LABEL_REPEATED: - for i in xrange(len(value)): - element = value[i] - prefix = "%s[%d]." % (name, i) - sub_errors = element.FindInitializationErrors() - errors += [ prefix + error for error in sub_errors ] - else: - prefix = name + "." - sub_errors = value.FindInitializationErrors() - errors += [ prefix + error for error in sub_errors ] - - return errors - - cls.FindInitializationErrors = FindInitializationErrors - - -def _AddMergeFromMethod(cls): - LABEL_REPEATED = _FieldDescriptor.LABEL_REPEATED - CPPTYPE_MESSAGE = _FieldDescriptor.CPPTYPE_MESSAGE - - def MergeFrom(self, msg): - assert msg is not self - self._Modified() - - fields = self._fields - - for field, value in msg._fields.iteritems(): - if field.label == LABEL_REPEATED or field.cpp_type == CPPTYPE_MESSAGE: - field_value = fields.get(field) - if field_value is None: - # Construct a new object to represent this field. - field_value = field._default_constructor(self) - fields[field] = field_value - field_value.MergeFrom(value) - else: - self._fields[field] = value - cls.MergeFrom = MergeFrom - - -def _AddMessageMethods(message_descriptor, cls): - """Adds implementations of all Message methods to cls.""" - _AddListFieldsMethod(message_descriptor, cls) - _AddHasFieldMethod(message_descriptor, cls) - _AddClearFieldMethod(message_descriptor, cls) - if message_descriptor.is_extendable: - _AddClearExtensionMethod(cls) - _AddHasExtensionMethod(cls) - _AddClearMethod(message_descriptor, cls) - _AddEqualsMethod(message_descriptor, cls) - _AddStrMethod(message_descriptor, cls) - _AddSetListenerMethod(cls) - _AddByteSizeMethod(message_descriptor, cls) - _AddSerializeToStringMethod(message_descriptor, cls) - _AddSerializePartialToStringMethod(message_descriptor, cls) - _AddMergeFromStringMethod(message_descriptor, cls) - _AddIsInitializedMethod(message_descriptor, cls) - _AddMergeFromMethod(cls) - - -def _AddPrivateHelperMethods(cls): - """Adds implementation of private helper methods to cls.""" - - def Modified(self): - """Sets the _cached_byte_size_dirty bit to true, - and propagates this to our listener iff this was a state change. - """ - - # Note: Some callers check _cached_byte_size_dirty before calling - # _Modified() as an extra optimization. So, if this method is ever - # changed such that it does stuff even when _cached_byte_size_dirty is - # already true, the callers need to be updated. - if not self._cached_byte_size_dirty: - self._cached_byte_size_dirty = True - self._listener_for_children.dirty = True - self._is_present_in_parent = True - self._listener.Modified() - - cls._Modified = Modified - cls.SetInParent = Modified - - -class _Listener(object): - - """MessageListener implementation that a parent message registers with its - child message. - - In order to support semantics like: - - foo.bar.baz.qux = 23 - assert foo.HasField('bar') - - ...child objects must have back references to their parents. - This helper class is at the heart of this support. - """ - - def __init__(self, parent_message): - """Args: - parent_message: The message whose _Modified() method we should call when - we receive Modified() messages. - """ - # This listener establishes a back reference from a child (contained) object - # to its parent (containing) object. We make this a weak reference to avoid - # creating cyclic garbage when the client finishes with the 'parent' object - # in the tree. - if isinstance(parent_message, weakref.ProxyType): - self._parent_message_weakref = parent_message - else: - self._parent_message_weakref = weakref.proxy(parent_message) - - # As an optimization, we also indicate directly on the listener whether - # or not the parent message is dirty. This way we can avoid traversing - # up the tree in the common case. - self.dirty = False - - def Modified(self): - if self.dirty: - return - try: - # Propagate the signal to our parents iff this is the first field set. - self._parent_message_weakref._Modified() - except ReferenceError: - # We can get here if a client has kept a reference to a child object, - # and is now setting a field on it, but the child's parent has been - # garbage-collected. This is not an error. - pass - - -# TODO(robinson): Move elsewhere? This file is getting pretty ridiculous... -# TODO(robinson): Unify error handling of "unknown extension" crap. -# TODO(robinson): Support iteritems()-style iteration over all -# extensions with the "has" bits turned on? -class _ExtensionDict(object): - - """Dict-like container for supporting an indexable "Extensions" - field on proto instances. - - Note that in all cases we expect extension handles to be - FieldDescriptors. + descriptor: A descriptor.Descriptor object describing the protobuf. + Returns: + The Message class object described by the descriptor. """ + attributes = {} + for name, nested_type in descriptor.nested_types_by_name.items(): + attributes[name] = MakeClass(nested_type) - def __init__(self, extended_message): - """extended_message: Message instance for which we are the Extensions dict. - """ - - self._extended_message = extended_message - - def __getitem__(self, extension_handle): - """Returns the current value of the given extension handle.""" - - _VerifyExtensionHandle(self._extended_message, extension_handle) - - result = self._extended_message._fields.get(extension_handle) - if result is not None: - return result - - if extension_handle.label == _FieldDescriptor.LABEL_REPEATED: - result = extension_handle._default_constructor(self._extended_message) - elif extension_handle.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: - result = extension_handle.message_type._concrete_class() - try: - result._SetListener(self._extended_message._listener_for_children) - except ReferenceError: - pass - else: - # Singular scalar -- just return the default without inserting into the - # dict. - return extension_handle.default_value - - # Atomically check if another thread has preempted us and, if not, swap - # in the new object we just created. If someone has preempted us, we - # take that object and discard ours. - # WARNING: We are relying on setdefault() being atomic. This is true - # in CPython but we haven't investigated others. This warning appears - # in several other locations in this file. - result = self._extended_message._fields.setdefault( - extension_handle, result) - - return result - - def __eq__(self, other): - if not isinstance(other, self.__class__): - return False + attributes[GeneratedProtocolMessageType._DESCRIPTOR_KEY] = descriptor - my_fields = self._extended_message.ListFields() - other_fields = other._extended_message.ListFields() - - # Get rid of non-extension fields. - my_fields = [ field for field in my_fields if field.is_extension ] - other_fields = [ field for field in other_fields if field.is_extension ] - - return my_fields == other_fields - - def __ne__(self, other): - return not self == other - - # Note that this is only meaningful for non-repeated, scalar extension - # fields. Note also that we may have to call _Modified() when we do - # successfully set a field this way, to set any necssary "has" bits in the - # ancestors of the extended message. - def __setitem__(self, extension_handle, value): - """If extension_handle specifies a non-repeated, scalar extension - field, sets the value of that field. - """ - - _VerifyExtensionHandle(self._extended_message, extension_handle) - - if (extension_handle.label == _FieldDescriptor.LABEL_REPEATED or - extension_handle.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE): - raise TypeError( - 'Cannot assign to extension "%s" because it is a repeated or ' - 'composite type.' % extension_handle.full_name) - - # It's slightly wasteful to lookup the type checker each time, - # but we expect this to be a vanishingly uncommon case anyway. - type_checker = type_checkers.GetTypeChecker( - extension_handle.cpp_type, extension_handle.type) - type_checker.CheckValue(value) - self._extended_message._fields[extension_handle] = value - self._extended_message._Modified() - - def _FindExtensionByName(self, name): - """Tries to find a known extension with the specified name. - - Args: - name: Extension full name. - - Returns: - Extension field descriptor. - """ - return self._extended_message._extensions_by_name.get(name, None) + return GeneratedProtocolMessageType(str(descriptor.name), (message.Message,), + attributes) |