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Diffstat (limited to 'third_party/protobuf/3.4.0/python/google/protobuf/internal/python_message.py')
-rwxr-xr-x | third_party/protobuf/3.4.0/python/google/protobuf/internal/python_message.py | 1544 |
1 files changed, 1544 insertions, 0 deletions
diff --git a/third_party/protobuf/3.4.0/python/google/protobuf/internal/python_message.py b/third_party/protobuf/3.4.0/python/google/protobuf/internal/python_message.py new file mode 100755 index 0000000000..c363d84324 --- /dev/null +++ b/third_party/protobuf/3.4.0/python/google/protobuf/internal/python_message.py @@ -0,0 +1,1544 @@ +# 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. + +# 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. + +Recall that a metaclass is the "type" of a class. +(A class is to a metaclass what an instance is to a class.) + +In this case, we use the GeneratedProtocolMessageType metaclass +to inject all the useful functionality into the classes +output by the protocol compiler at compile-time. + +The upshot of all this is that the real implementation +details for ALL pure-Python protocol buffers are *here in +this file*. +""" + +__author__ = 'robinson@google.com (Will Robinson)' + +from io import BytesIO +import struct +import sys +import weakref + +import six + +# We use "as" to avoid name collisions with variables. +from google.protobuf.internal import api_implementation +from google.protobuf.internal import containers +from google.protobuf.internal import decoder +from google.protobuf.internal import encoder +from google.protobuf.internal import enum_type_wrapper +from google.protobuf.internal import message_listener as message_listener_mod +from google.protobuf.internal import type_checkers +from google.protobuf.internal import well_known_types +from google.protobuf.internal import wire_format +from google.protobuf import descriptor as descriptor_mod +from google.protobuf import message as message_mod +from google.protobuf import text_format + +_FieldDescriptor = descriptor_mod.FieldDescriptor +_AnyFullTypeName = 'google.protobuf.Any' + + +class GeneratedProtocolMessageType(type): + + """Metaclass for protocol message classes created at runtime from Descriptors. + + We add implementations for all methods described in the Message class. We + also create properties to allow getting/setting all fields in the protocol + message. Finally, we create slots to prevent users from accidentally + "setting" nonexistent fields in the protocol message, which then wouldn't get + serialized / deserialized properly. + + The protocol compiler currently uses this metaclass to create protocol + message classes at runtime. Clients can also manually create their own + classes at runtime, as in this example: + + mydescriptor = Descriptor(.....) + factory = symbol_database.Default() + factory.pool.AddDescriptor(mydescriptor) + MyProtoClass = factory.GetPrototype(mydescriptor) + myproto_instance = MyProtoClass() + myproto.foo_field = 23 + ... + """ + + # Must be consistent with the protocol-compiler code in + # proto2/compiler/internal/generator.*. + _DESCRIPTOR_KEY = 'DESCRIPTOR' + + def __new__(cls, name, bases, dictionary): + """Custom allocation for runtime-generated class types. + + We override __new__ because this is apparently the only place + where we can meaningfully set __slots__ on the class we're creating(?). + (The interplay between metaclasses and slots is not very well-documented). + + Args: + name: Name of the class (ignored, but required by the + metaclass protocol). + bases: Base classes of the class we're constructing. + (Should be message.Message). We ignore this field, but + it's required by the metaclass protocol + dictionary: The class dictionary of the class we're + constructing. dictionary[_DESCRIPTOR_KEY] must contain + a Descriptor object describing this protocol message + type. + + Returns: + Newly-allocated class. + """ + descriptor = dictionary[GeneratedProtocolMessageType._DESCRIPTOR_KEY] + if descriptor.full_name in well_known_types.WKTBASES: + bases += (well_known_types.WKTBASES[descriptor.full_name],) + _AddClassAttributesForNestedExtensions(descriptor, dictionary) + _AddSlots(descriptor, dictionary) + + superclass = super(GeneratedProtocolMessageType, cls) + new_class = superclass.__new__(cls, name, bases, dictionary) + return new_class + + def __init__(cls, name, bases, dictionary): + """Here we perform the majority of our work on the class. + We add enum getters, an __init__ method, implementations + of all Message methods, and properties for all fields + in the protocol type. + + Args: + name: Name of the class (ignored, but required by the + metaclass protocol). + bases: Base classes of the class we're constructing. + (Should be message.Message). We ignore this field, but + it's required by the metaclass protocol + dictionary: The class dictionary of the class we're + constructing. dictionary[_DESCRIPTOR_KEY] must contain + a Descriptor object describing this protocol message + type. + """ + descriptor = dictionary[GeneratedProtocolMessageType._DESCRIPTOR_KEY] + cls._decoders_by_tag = {} + if (descriptor.has_options and + descriptor.GetOptions().message_set_wire_format): + cls._decoders_by_tag[decoder.MESSAGE_SET_ITEM_TAG] = ( + decoder.MessageSetItemDecoder(descriptor), None) + + # Attach stuff to each FieldDescriptor for quick lookup later on. + for field in descriptor.fields: + _AttachFieldHelpers(cls, field) + + descriptor._concrete_class = cls # pylint: disable=protected-access + _AddEnumValues(descriptor, cls) + _AddInitMethod(descriptor, cls) + _AddPropertiesForFields(descriptor, cls) + _AddPropertiesForExtensions(descriptor, cls) + _AddStaticMethods(cls) + _AddMessageMethods(descriptor, cls) + _AddPrivateHelperMethods(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 not extension_handle.containing_type: + raise KeyError('"%s" is missing a containing_type.' + % 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', + '_unknown_fields', + '_is_present_in_parent', + '_listener', + '_listener_for_children', + '__weakref__', + '_oneofs'] + + +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.label == _FieldDescriptor.LABEL_OPTIONAL) + + +def _IsMapField(field): + return (field.type == _FieldDescriptor.TYPE_MESSAGE and + field.message_type.has_options and + field.message_type.GetOptions().map_entry) + + +def _IsMessageMapField(field): + value_type = field.message_type.fields_by_name["value"] + return value_type.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE + + +def _AttachFieldHelpers(cls, field_descriptor): + is_repeated = (field_descriptor.label == _FieldDescriptor.LABEL_REPEATED) + is_packable = (is_repeated and + wire_format.IsTypePackable(field_descriptor.type)) + if not is_packable: + is_packed = False + elif field_descriptor.containing_type.syntax == "proto2": + is_packed = (field_descriptor.has_options and + field_descriptor.GetOptions().packed) + else: + has_packed_false = (field_descriptor.has_options and + field_descriptor.GetOptions().HasField("packed") and + field_descriptor.GetOptions().packed == False) + is_packed = not has_packed_false + is_map_entry = _IsMapField(field_descriptor) + + if is_map_entry: + field_encoder = encoder.MapEncoder(field_descriptor) + sizer = encoder.MapSizer(field_descriptor, + _IsMessageMapField(field_descriptor)) + elif _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) + decode_type = field_descriptor.type + if (decode_type == _FieldDescriptor.TYPE_ENUM and + type_checkers.SupportsOpenEnums(field_descriptor)): + decode_type = _FieldDescriptor.TYPE_INT32 + + oneof_descriptor = None + if field_descriptor.containing_oneof is not None: + oneof_descriptor = field_descriptor + + if is_map_entry: + is_message_map = _IsMessageMapField(field_descriptor) + + field_decoder = decoder.MapDecoder( + field_descriptor, _GetInitializeDefaultForMap(field_descriptor), + is_message_map) + else: + field_decoder = type_checkers.TYPE_TO_DECODER[decode_type]( + field_descriptor.number, is_repeated, is_packed, + field_descriptor, field_descriptor._default_constructor) + + cls._decoders_by_tag[tag_bytes] = (field_decoder, oneof_descriptor) + + 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.items(): + 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. + + Also exporting a class-level object that can name enum values. + + Args: + descriptor: Descriptor object for this message type. + cls: Class we're constructing for this message type. + """ + for enum_type in descriptor.enum_types: + setattr(cls, enum_type.name, enum_type_wrapper.EnumTypeWrapper(enum_type)) + for enum_value in enum_type.values: + setattr(cls, enum_value.name, enum_value.number) + + +def _GetInitializeDefaultForMap(field): + if field.label != _FieldDescriptor.LABEL_REPEATED: + raise ValueError('map_entry set on non-repeated field %s' % ( + field.name)) + fields_by_name = field.message_type.fields_by_name + key_checker = type_checkers.GetTypeChecker(fields_by_name['key']) + + value_field = fields_by_name['value'] + if _IsMessageMapField(field): + def MakeMessageMapDefault(message): + return containers.MessageMap( + message._listener_for_children, value_field.message_type, key_checker, + field.message_type) + return MakeMessageMapDefault + else: + value_checker = type_checkers.GetTypeChecker(value_field) + def MakePrimitiveMapDefault(message): + return containers.ScalarMap( + message._listener_for_children, key_checker, value_checker, + field.message_type) + return MakePrimitiveMapDefault + +def _DefaultValueConstructorForField(field): + """Returns a function which returns a default value for a field. + + Args: + field: FieldDescriptor object for this field. + + 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 _IsMapField(field): + return _GetInitializeDefaultForMap(field) + + if field.label == _FieldDescriptor.LABEL_REPEATED: + if field.has_default_value and 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) + 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( + _OneofListener(message, field) + if field.containing_oneof is not None + else message._listener_for_children) + return result + return MakeSubMessageDefault + + def MakeScalarDefault(message): + # TODO(protobuf-team): This may be broken since there may not be + # default_value. Combine with has_default_value somehow. + return field.default_value + return MakeScalarDefault + + +def _ReraiseTypeErrorWithFieldName(message_name, field_name): + """Re-raise the currently-handled TypeError with the field name added.""" + exc = sys.exc_info()[1] + if len(exc.args) == 1 and type(exc) is TypeError: + # simple TypeError; add field name to exception message + exc = TypeError('%s for field %s.%s' % (str(exc), message_name, field_name)) + + # re-raise possibly-amended exception with original traceback: + six.reraise(type(exc), exc, sys.exc_info()[2]) + + +def _AddInitMethod(message_descriptor, cls): + """Adds an __init__ method to cls.""" + + def _GetIntegerEnumValue(enum_type, value): + """Convert a string or integer enum value to an integer. + + If the value is a string, it is converted to the enum value in + enum_type with the same name. If the value is not a string, it's + returned as-is. (No conversion or bounds-checking is done.) + """ + if isinstance(value, six.string_types): + try: + return enum_type.values_by_name[value].number + except KeyError: + raise ValueError('Enum type %s: unknown label "%s"' % ( + enum_type.full_name, value)) + return value + + def init(self, **kwargs): + self._cached_byte_size = 0 + self._cached_byte_size_dirty = len(kwargs) > 0 + self._fields = {} + # Contains a mapping from oneof field descriptors to the descriptor + # of the currently set field in that oneof field. + self._oneofs = {} + + # _unknown_fields is () when empty for efficiency, and will be turned into + # a list if fields are added. + self._unknown_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.items(): + 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_value is None: + # field=None is the same as no field at all. + continue + if field.label == _FieldDescriptor.LABEL_REPEATED: + copy = field._default_constructor(self) + if field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: # Composite + if _IsMapField(field): + if _IsMessageMapField(field): + for key in field_value: + copy[key].MergeFrom(field_value[key]) + else: + copy.update(field_value) + else: + for val in field_value: + if isinstance(val, dict): + copy.add(**val) + else: + copy.add().MergeFrom(val) + else: # Scalar + if field.cpp_type == _FieldDescriptor.CPPTYPE_ENUM: + field_value = [_GetIntegerEnumValue(field.enum_type, val) + for val in field_value] + copy.extend(field_value) + self._fields[field] = copy + elif field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: + copy = field._default_constructor(self) + new_val = field_value + if isinstance(field_value, dict): + new_val = field.message_type._concrete_class(**field_value) + try: + copy.MergeFrom(new_val) + except TypeError: + _ReraiseTypeErrorWithFieldName(message_descriptor.name, field_name) + self._fields[field] = copy + else: + if field.cpp_type == _FieldDescriptor.CPPTYPE_ENUM: + field_value = _GetIntegerEnumValue(field.enum_type, field_value) + try: + setattr(self, field_name, field_value) + except TypeError: + _ReraiseTypeErrorWithFieldName(message_descriptor.name, field_name) + + 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 %s has no "%s" field.' % + (message_descriptor.name, 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) + default_value = field.default_value + valid_values = set() + is_proto3 = field.containing_type.syntax == "proto3" + + def getter(self): + # TODO(protobuf-team): This may be broken since there may not be + # default_value. Combine with has_default_value somehow. + return self._fields.get(field, default_value) + getter.__module__ = None + getter.__doc__ = 'Getter for %s.' % proto_field_name + + clear_when_set_to_default = is_proto3 and not field.containing_oneof + + def field_setter(self, new_value): + # pylint: disable=protected-access + # Testing the value for truthiness captures all of the proto3 defaults + # (0, 0.0, enum 0, and False). + new_value = type_checker.CheckValue(new_value) + if clear_when_set_to_default and not new_value: + self._fields.pop(field, None) + else: + 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() + + if field.containing_oneof: + def setter(self, new_value): + field_setter(self, new_value) + self._UpdateOneofState(field) + else: + setter = field_setter + + 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. + """ + # TODO(robinson): Remove duplication with similar method + # for non-repeated scalars. + 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 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.items(): + constant_name = extension_name.upper() + "_FIELD_NUMBER" + setattr(cls, constant_name, extension_field.number) + + # TODO(amauryfa): Migrate all users of these attributes to functions like + # pool.FindExtensionByNumber(descriptor). + if descriptor.file is not None: + # TODO(amauryfa): Use cls.MESSAGE_FACTORY.pool when available. + pool = descriptor.file.pool + cls._extensions_by_number = pool._extensions_by_number[descriptor] + cls._extensions_by_name = pool._extensions_by_name[descriptor] + +def _AddStaticMethods(cls): + # TODO(robinson): This probably needs to be thread-safe(?) + def RegisterExtension(extension_handle): + extension_handle.containing_type = cls.DESCRIPTOR + # TODO(amauryfa): Use cls.MESSAGE_FACTORY.pool when available. + cls.DESCRIPTOR.file.pool.AddExtensionDescriptor(extension_handle) + _AttachFieldHelpers(cls, 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.items() if _IsPresent(item)] + all_fields.sort(key = lambda item: item[0].number) + return all_fields + + cls.ListFields = ListFields + +_Proto3HasError = 'Protocol message has no non-repeated submessage field "%s"' +_Proto2HasError = 'Protocol message has no non-repeated field "%s"' + +def _AddHasFieldMethod(message_descriptor, cls): + """Helper for _AddMessageMethods().""" + + is_proto3 = (message_descriptor.syntax == "proto3") + error_msg = _Proto3HasError if is_proto3 else _Proto2HasError + + hassable_fields = {} + for field in message_descriptor.fields: + if field.label == _FieldDescriptor.LABEL_REPEATED: + continue + # For proto3, only submessages and fields inside a oneof have presence. + if (is_proto3 and field.cpp_type != _FieldDescriptor.CPPTYPE_MESSAGE and + not field.containing_oneof): + continue + hassable_fields[field.name] = field + + if not is_proto3: + # Fields inside oneofs are never repeated (enforced by the compiler). + for oneof in message_descriptor.oneofs: + hassable_fields[oneof.name] = oneof + + def HasField(self, field_name): + try: + field = hassable_fields[field_name] + except KeyError: + raise ValueError(error_msg % field_name) + + if isinstance(field, descriptor_mod.OneofDescriptor): + try: + return HasField(self, self._oneofs[field].name) + except KeyError: + return False + else: + 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 + + +def _AddClearFieldMethod(message_descriptor, cls): + """Helper for _AddMessageMethods().""" + def ClearField(self, field_name): + try: + field = message_descriptor.fields_by_name[field_name] + except KeyError: + try: + field = message_descriptor.oneofs_by_name[field_name] + if field in self._oneofs: + field = self._oneofs[field] + else: + return + except KeyError: + raise ValueError('Protocol message %s() has no "%s" field.' % + (message_descriptor.name, field_name)) + + if field in self._fields: + # To match the C++ implementation, we need to invalidate iterators + # for map fields when ClearField() happens. + if hasattr(self._fields[field], 'InvalidateIterators'): + self._fields[field].InvalidateIterators() + + # 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] + + if self._oneofs.get(field.containing_oneof, None) is field: + del self._oneofs[field.containing_oneof] + + # 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 _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 _InternalUnpackAny(msg): + """Unpacks Any message and returns the unpacked message. + + This internal method is different from public Any Unpack method which takes + the target message as argument. _InternalUnpackAny method does not have + target message type and need to find the message type in descriptor pool. + + Args: + msg: An Any message to be unpacked. + + Returns: + The unpacked message. + """ + # TODO(amauryfa): Don't use the factory of generated messages. + # To make Any work with custom factories, use the message factory of the + # parent message. + # pylint: disable=g-import-not-at-top + from google.protobuf import symbol_database + factory = symbol_database.Default() + + type_url = msg.type_url + + if not type_url: + return None + + # TODO(haberman): For now we just strip the hostname. Better logic will be + # required. + type_name = type_url.split('/')[-1] + descriptor = factory.pool.FindMessageTypeByName(type_name) + + if descriptor is None: + return None + + message_class = factory.GetPrototype(descriptor) + message = message_class() + + message.ParseFromString(msg.value) + return message + + +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 + + if self.DESCRIPTOR.full_name == _AnyFullTypeName: + any_a = _InternalUnpackAny(self) + any_b = _InternalUnpackAny(other) + if any_a and any_b: + return any_a == any_b + + if not self.ListFields() == other.ListFields(): + return False + + # Sort unknown fields because their order shouldn't affect equality test. + unknown_fields = list(self._unknown_fields) + unknown_fields.sort() + other_unknown_fields = list(other._unknown_fields) + other_unknown_fields.sort() + + return unknown_fields == other_unknown_fields + + cls.__eq__ = __eq__ + + +def _AddStrMethod(message_descriptor, cls): + """Helper for _AddMessageMethods().""" + def __str__(self): + return text_format.MessageToString(self) + cls.__str__ = __str__ + + +def _AddReprMethod(message_descriptor, cls): + """Helper for _AddMessageMethods().""" + def __repr__(self): + return text_format.MessageToString(self) + cls.__repr__ = __repr__ + + +def _AddUnicodeMethod(unused_message_descriptor, cls): + """Helper for _AddMessageMethods().""" + + def __unicode__(self): + return text_format.MessageToString(self, as_utf8=True).decode('utf-8') + cls.__unicode__ = __unicode__ + + +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. + + 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) + + for tag_bytes, value_bytes in self._unknown_fields: + size += len(tag_bytes) + len(value_bytes) + + 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, **kwargs): + # Check if the message has all of its required fields set. + errors = [] + if not self.IsInitialized(): + raise message_mod.EncodeError( + 'Message %s is missing required fields: %s' % ( + self.DESCRIPTOR.full_name, ','.join(self.FindInitializationErrors()))) + return self.SerializePartialToString(**kwargs) + cls.SerializeToString = SerializeToString + + +def _AddSerializePartialToStringMethod(message_descriptor, cls): + """Helper for _AddMessageMethods().""" + + def SerializePartialToString(self, **kwargs): + out = BytesIO() + self._InternalSerialize(out.write, **kwargs) + return out.getvalue() + cls.SerializePartialToString = SerializePartialToString + + def InternalSerialize(self, write_bytes, deterministic=None): + if deterministic is None: + deterministic = ( + api_implementation.IsPythonDefaultSerializationDeterministic()) + else: + deterministic = bool(deterministic) + for field_descriptor, field_value in self.ListFields(): + field_descriptor._encoder(write_bytes, field_value, deterministic) + for tag_bytes, value_bytes in self._unknown_fields: + write_bytes(tag_bytes) + write_bytes(value_bytes) + 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, TypeError): + # Now ord(buf[p:p+1]) == ord('') gets TypeError. + raise message_mod.DecodeError('Truncated message.') + except struct.error as 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 + is_proto3 = message_descriptor.syntax == "proto3" + + def InternalParse(self, buffer, pos, end): + self._Modified() + field_dict = self._fields + unknown_field_list = self._unknown_fields + while pos != end: + (tag_bytes, new_pos) = local_ReadTag(buffer, pos) + field_decoder, field_desc = decoders_by_tag.get(tag_bytes, (None, None)) + if field_decoder is None: + value_start_pos = new_pos + new_pos = local_SkipField(buffer, new_pos, end, tag_bytes) + if new_pos == -1: + return pos + if not is_proto3: + if not unknown_field_list: + unknown_field_list = self._unknown_fields = [] + unknown_field_list.append( + (tag_bytes, buffer[value_start_pos:new_pos])) + pos = new_pos + else: + pos = field_decoder(buffer, new_pos, end, self, field_dict) + if field_desc: + self._UpdateOneofState(field_desc) + 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 list(self._fields.items()): # dict can change size! + if field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: + if field.label == _FieldDescriptor.LABEL_REPEATED: + if (field.message_type.has_options and + field.message_type.GetOptions().map_entry): + continue + 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 _IsMapField(field): + if _IsMessageMapField(field): + for key in value: + element = value[key] + prefix = "%s[%s]." % (name, key) + sub_errors = element.FindInitializationErrors() + errors += [prefix + error for error in sub_errors] + else: + # ScalarMaps can't have any initialization errors. + pass + elif field.label == _FieldDescriptor.LABEL_REPEATED: + for i in range(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): + if not isinstance(msg, cls): + raise TypeError( + "Parameter to MergeFrom() must be instance of same class: " + 'expected %s got %s.' % (cls.__name__, msg.__class__.__name__)) + + assert msg is not self + self._Modified() + + fields = self._fields + + for field, value in msg._fields.items(): + if field.label == LABEL_REPEATED: + 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) + elif field.cpp_type == CPPTYPE_MESSAGE: + if value._is_present_in_parent: + 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 + if field.containing_oneof: + self._UpdateOneofState(field) + + if msg._unknown_fields: + if not self._unknown_fields: + self._unknown_fields = [] + self._unknown_fields.extend(msg._unknown_fields) + + cls.MergeFrom = MergeFrom + + +def _AddWhichOneofMethod(message_descriptor, cls): + def WhichOneof(self, oneof_name): + """Returns the name of the currently set field inside a oneof, or None.""" + try: + field = message_descriptor.oneofs_by_name[oneof_name] + except KeyError: + raise ValueError( + 'Protocol message has no oneof "%s" field.' % oneof_name) + + nested_field = self._oneofs.get(field, None) + if nested_field is not None and self.HasField(nested_field.name): + return nested_field.name + else: + return None + + cls.WhichOneof = WhichOneof + + +def _AddReduceMethod(cls): + def __reduce__(self): # pylint: disable=invalid-name + return (type(self), (), self.__getstate__()) + cls.__reduce__ = __reduce__ + + +def _Clear(self): + # Clear fields. + self._fields = {} + self._unknown_fields = () + self._oneofs = {} + self._Modified() + + +def _DiscardUnknownFields(self): + self._unknown_fields = [] + for field, value in self.ListFields(): + if field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE: + if field.label == _FieldDescriptor.LABEL_REPEATED: + for sub_message in value: + sub_message.DiscardUnknownFields() + else: + value.DiscardUnknownFields() + + +def _SetListener(self, listener): + if listener is None: + self._listener = message_listener_mod.NullMessageListener() + else: + self._listener = listener + + +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) + _AddEqualsMethod(message_descriptor, cls) + _AddStrMethod(message_descriptor, cls) + _AddReprMethod(message_descriptor, cls) + _AddUnicodeMethod(message_descriptor, cls) + _AddByteSizeMethod(message_descriptor, cls) + _AddSerializeToStringMethod(message_descriptor, cls) + _AddSerializePartialToStringMethod(message_descriptor, cls) + _AddMergeFromStringMethod(message_descriptor, cls) + _AddIsInitializedMethod(message_descriptor, cls) + _AddMergeFromMethod(cls) + _AddWhichOneofMethod(message_descriptor, cls) + _AddReduceMethod(cls) + # Adds methods which do not depend on cls. + cls.Clear = _Clear + cls.DiscardUnknownFields = _DiscardUnknownFields + cls._SetListener = _SetListener + + +def _AddPrivateHelperMethods(message_descriptor, 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() + + def _UpdateOneofState(self, field): + """Sets field as the active field in its containing oneof. + + Will also delete currently active field in the oneof, if it is different + from the argument. Does not mark the message as modified. + """ + other_field = self._oneofs.setdefault(field.containing_oneof, field) + if other_field is not field: + del self._fields[other_field] + self._oneofs[field.containing_oneof] = field + + cls._Modified = Modified + cls.SetInParent = Modified + cls._UpdateOneofState = _UpdateOneofState + + +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 + + +class _OneofListener(_Listener): + """Special listener implementation for setting composite oneof fields.""" + + def __init__(self, parent_message, field): + """Args: + parent_message: The message whose _Modified() method we should call when + we receive Modified() messages. + field: The descriptor of the field being set in the parent message. + """ + super(_OneofListener, self).__init__(parent_message) + self._field = field + + def Modified(self): + """Also updates the state of the containing oneof in the parent message.""" + try: + self._parent_message_weakref._UpdateOneofState(self._field) + super(_OneofListener, self).Modified() + except ReferenceError: + 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. + """ + + 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 + + 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 + + def __hash__(self): + raise TypeError('unhashable object') + + # 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) + # pylint: disable=protected-access + self._extended_message._fields[extension_handle] = ( + type_checker.CheckValue(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) + + def _FindExtensionByNumber(self, number): + """Tries to find a known extension with the field number. + + Args: + number: Extension field number. + + Returns: + Extension field descriptor. + """ + return self._extended_message._extensions_by_number.get(number, None) |