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# Protocol Buffers - Google's data interchange format
# Copyright 2008 Google Inc. All rights reserved.
# http://code.google.com/p/protobuf/
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
# * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""Contains helper functions used to create protocol message classes from
Descriptor objects at runtime backed by the protocol buffer C++ API.
"""
__author__ = 'petar@google.com (Petar Petrov)'
import copy_reg
import operator
from google.protobuf.internal import _net_proto2___python
from google.protobuf.internal import enum_type_wrapper
from google.protobuf import message
_LABEL_REPEATED = _net_proto2___python.LABEL_REPEATED
_LABEL_OPTIONAL = _net_proto2___python.LABEL_OPTIONAL
_CPPTYPE_MESSAGE = _net_proto2___python.CPPTYPE_MESSAGE
_TYPE_MESSAGE = _net_proto2___python.TYPE_MESSAGE
def GetDescriptorPool():
"""Creates a new DescriptorPool C++ object."""
return _net_proto2___python.NewCDescriptorPool()
_pool = GetDescriptorPool()
def GetFieldDescriptor(full_field_name):
"""Searches for a field descriptor given a full field name."""
return _pool.FindFieldByName(full_field_name)
def BuildFile(content):
"""Registers a new proto file in the underlying C++ descriptor pool."""
_net_proto2___python.BuildFile(content)
def GetExtensionDescriptor(full_extension_name):
"""Searches for extension descriptor given a full field name."""
return _pool.FindExtensionByName(full_extension_name)
def NewCMessage(full_message_name):
"""Creates a new C++ protocol message by its name."""
return _net_proto2___python.NewCMessage(full_message_name)
def ScalarProperty(cdescriptor):
"""Returns a scalar property for the given descriptor."""
def Getter(self):
return self._cmsg.GetScalar(cdescriptor)
def Setter(self, value):
self._cmsg.SetScalar(cdescriptor, value)
return property(Getter, Setter)
def CompositeProperty(cdescriptor, message_type):
"""Returns a Python property the given composite field."""
def Getter(self):
sub_message = self._composite_fields.get(cdescriptor.name, None)
if sub_message is None:
cmessage = self._cmsg.NewSubMessage(cdescriptor)
sub_message = message_type._concrete_class(__cmessage=cmessage)
self._composite_fields[cdescriptor.name] = sub_message
return sub_message
return property(Getter)
class RepeatedScalarContainer(object):
"""Container for repeated scalar fields."""
__slots__ = ['_message', '_cfield_descriptor', '_cmsg']
def __init__(self, msg, cfield_descriptor):
self._message = msg
self._cmsg = msg._cmsg
self._cfield_descriptor = cfield_descriptor
def append(self, value):
self._cmsg.AddRepeatedScalar(
self._cfield_descriptor, value)
def extend(self, sequence):
for element in sequence:
self.append(element)
def insert(self, key, value):
values = self[slice(None, None, None)]
values.insert(key, value)
self._cmsg.AssignRepeatedScalar(self._cfield_descriptor, values)
def remove(self, value):
values = self[slice(None, None, None)]
values.remove(value)
self._cmsg.AssignRepeatedScalar(self._cfield_descriptor, values)
def __setitem__(self, key, value):
values = self[slice(None, None, None)]
values[key] = value
self._cmsg.AssignRepeatedScalar(self._cfield_descriptor, values)
def __getitem__(self, key):
return self._cmsg.GetRepeatedScalar(self._cfield_descriptor, key)
def __delitem__(self, key):
self._cmsg.DeleteRepeatedField(self._cfield_descriptor, key)
def __len__(self):
return len(self[slice(None, None, None)])
def __eq__(self, other):
if self is other:
return True
if not operator.isSequenceType(other):
raise TypeError(
'Can only compare repeated scalar fields against sequences.')
# We are presumably comparing against some other sequence type.
return other == self[slice(None, None, None)]
def __ne__(self, other):
return not self == other
def __hash__(self):
raise TypeError('unhashable object')
def sort(self, *args, **kwargs):
# Maintain compatibility with the previous interface.
if 'sort_function' in kwargs:
kwargs['cmp'] = kwargs.pop('sort_function')
self._cmsg.AssignRepeatedScalar(self._cfield_descriptor,
sorted(self, *args, **kwargs))
def RepeatedScalarProperty(cdescriptor):
"""Returns a Python property the given repeated scalar field."""
def Getter(self):
container = self._composite_fields.get(cdescriptor.name, None)
if container is None:
container = RepeatedScalarContainer(self, cdescriptor)
self._composite_fields[cdescriptor.name] = container
return container
def Setter(self, new_value):
raise AttributeError('Assignment not allowed to repeated field '
'"%s" in protocol message object.' % cdescriptor.name)
doc = 'Magic attribute generated for "%s" proto field.' % cdescriptor.name
return property(Getter, Setter, doc=doc)
class RepeatedCompositeContainer(object):
"""Container for repeated composite fields."""
__slots__ = ['_message', '_subclass', '_cfield_descriptor', '_cmsg']
def __init__(self, msg, cfield_descriptor, subclass):
self._message = msg
self._cmsg = msg._cmsg
self._subclass = subclass
self._cfield_descriptor = cfield_descriptor
def add(self, **kwargs):
cmessage = self._cmsg.AddMessage(self._cfield_descriptor)
return self._subclass(__cmessage=cmessage, __owner=self._message, **kwargs)
def extend(self, elem_seq):
"""Extends by appending the given sequence of elements of the same type
as this one, copying each individual message.
"""
for message in elem_seq:
self.add().MergeFrom(message)
def remove(self, value):
# TODO(protocol-devel): This is inefficient as it needs to generate a
# message pointer for each message only to do index(). Move this to a C++
# extension function.
self.__delitem__(self[slice(None, None, None)].index(value))
def MergeFrom(self, other):
for message in other[:]:
self.add().MergeFrom(message)
def __getitem__(self, key):
cmessages = self._cmsg.GetRepeatedMessage(
self._cfield_descriptor, key)
subclass = self._subclass
if not isinstance(cmessages, list):
return subclass(__cmessage=cmessages, __owner=self._message)
return [subclass(__cmessage=m, __owner=self._message) for m in cmessages]
def __delitem__(self, key):
self._cmsg.DeleteRepeatedField(
self._cfield_descriptor, key)
def __len__(self):
return self._cmsg.FieldLength(self._cfield_descriptor)
def __eq__(self, other):
"""Compares the current instance with another one."""
if self is other:
return True
if not isinstance(other, self.__class__):
raise TypeError('Can only compare repeated composite fields against '
'other repeated composite fields.')
messages = self[slice(None, None, None)]
other_messages = other[slice(None, None, None)]
return messages == other_messages
def __hash__(self):
raise TypeError('unhashable object')
def sort(self, cmp=None, key=None, reverse=False, **kwargs):
# Maintain compatibility with the old interface.
if cmp is None and 'sort_function' in kwargs:
cmp = kwargs.pop('sort_function')
# The cmp function, if provided, is passed the results of the key function,
# so we only need to wrap one of them.
if key is None:
index_key = self.__getitem__
else:
index_key = lambda i: key(self[i])
# Sort the list of current indexes by the underlying object.
indexes = range(len(self))
indexes.sort(cmp=cmp, key=index_key, reverse=reverse)
# Apply the transposition.
for dest, src in enumerate(indexes):
if dest == src:
continue
self._cmsg.SwapRepeatedFieldElements(self._cfield_descriptor, dest, src)
# Don't swap the same value twice.
indexes[src] = src
def RepeatedCompositeProperty(cdescriptor, message_type):
"""Returns a Python property for the given repeated composite field."""
def Getter(self):
container = self._composite_fields.get(cdescriptor.name, None)
if container is None:
container = RepeatedCompositeContainer(
self, cdescriptor, message_type._concrete_class)
self._composite_fields[cdescriptor.name] = container
return container
def Setter(self, new_value):
raise AttributeError('Assignment not allowed to repeated field '
'"%s" in protocol message object.' % cdescriptor.name)
doc = 'Magic attribute generated for "%s" proto field.' % cdescriptor.name
return property(Getter, Setter, doc=doc)
class ExtensionDict(object):
"""Extension dictionary added to each protocol message."""
def __init__(self, msg):
self._message = msg
self._cmsg = msg._cmsg
self._values = {}
def __setitem__(self, extension, value):
from google.protobuf import descriptor
if not isinstance(extension, descriptor.FieldDescriptor):
raise KeyError('Bad extension %r.' % (extension,))
cdescriptor = extension._cdescriptor
if (cdescriptor.label != _LABEL_OPTIONAL or
cdescriptor.cpp_type == _CPPTYPE_MESSAGE):
raise TypeError('Extension %r is repeated and/or a composite type.' % (
extension.full_name,))
self._cmsg.SetScalar(cdescriptor, value)
self._values[extension] = value
def __getitem__(self, extension):
from google.protobuf import descriptor
if not isinstance(extension, descriptor.FieldDescriptor):
raise KeyError('Bad extension %r.' % (extension,))
cdescriptor = extension._cdescriptor
if (cdescriptor.label != _LABEL_REPEATED and
cdescriptor.cpp_type != _CPPTYPE_MESSAGE):
return self._cmsg.GetScalar(cdescriptor)
ext = self._values.get(extension, None)
if ext is not None:
return ext
ext = self._CreateNewHandle(extension)
self._values[extension] = ext
return ext
def ClearExtension(self, extension):
from google.protobuf import descriptor
if not isinstance(extension, descriptor.FieldDescriptor):
raise KeyError('Bad extension %r.' % (extension,))
self._cmsg.ClearFieldByDescriptor(extension._cdescriptor)
if extension in self._values:
del self._values[extension]
def HasExtension(self, extension):
from google.protobuf import descriptor
if not isinstance(extension, descriptor.FieldDescriptor):
raise KeyError('Bad extension %r.' % (extension,))
return self._cmsg.HasFieldByDescriptor(extension._cdescriptor)
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._message._extensions_by_name.get(name, None)
def _CreateNewHandle(self, extension):
cdescriptor = extension._cdescriptor
if (cdescriptor.label != _LABEL_REPEATED and
cdescriptor.cpp_type == _CPPTYPE_MESSAGE):
cmessage = self._cmsg.NewSubMessage(cdescriptor)
return extension.message_type._concrete_class(__cmessage=cmessage)
if cdescriptor.label == _LABEL_REPEATED:
if cdescriptor.cpp_type == _CPPTYPE_MESSAGE:
return RepeatedCompositeContainer(
self._message, cdescriptor, extension.message_type._concrete_class)
else:
return RepeatedScalarContainer(self._message, cdescriptor)
# This shouldn't happen!
assert False
return None
def NewMessage(bases, message_descriptor, dictionary):
"""Creates a new protocol message *class*."""
_AddClassAttributesForNestedExtensions(message_descriptor, dictionary)
_AddEnumValues(message_descriptor, dictionary)
_AddDescriptors(message_descriptor, dictionary)
return bases
def InitMessage(message_descriptor, cls):
"""Constructs a new message instance (called before instance's __init__)."""
cls._extensions_by_name = {}
_AddInitMethod(message_descriptor, cls)
_AddMessageMethods(message_descriptor, cls)
_AddPropertiesForExtensions(message_descriptor, cls)
copy_reg.pickle(cls, lambda obj: (cls, (), obj.__getstate__()))
def _AddDescriptors(message_descriptor, dictionary):
"""Sets up a new protocol message class dictionary.
Args:
message_descriptor: A Descriptor instance describing this message type.
dictionary: Class dictionary to which we'll add a '__slots__' entry.
"""
dictionary['__descriptors'] = {}
for field in message_descriptor.fields:
dictionary['__descriptors'][field.name] = GetFieldDescriptor(
field.full_name)
dictionary['__slots__'] = list(dictionary['__descriptors'].iterkeys()) + [
'_cmsg', '_owner', '_composite_fields', 'Extensions', '_HACK_REFCOUNTS']
def _AddEnumValues(message_descriptor, dictionary):
"""Sets class-level attributes for all enum fields defined in this message.
Args:
message_descriptor: Descriptor object for this message type.
dictionary: Class dictionary that should be populated.
"""
for enum_type in message_descriptor.enum_types:
dictionary[enum_type.name] = enum_type_wrapper.EnumTypeWrapper(enum_type)
for enum_value in enum_type.values:
dictionary[enum_value.name] = enum_value.number
def _AddClassAttributesForNestedExtensions(message_descriptor, dictionary):
"""Adds class attributes for the nested extensions."""
extension_dict = message_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 _AddInitMethod(message_descriptor, cls):
"""Adds an __init__ method to cls."""
# Create and attach message field properties to the message class.
# This can be done just once per message class, since property setters and
# getters are passed the message instance.
# This makes message instantiation extremely fast, and at the same time it
# doesn't require the creation of property objects for each message instance,
# which saves a lot of memory.
for field in message_descriptor.fields:
field_cdescriptor = cls.__descriptors[field.name]
if field.label == _LABEL_REPEATED:
if field.cpp_type == _CPPTYPE_MESSAGE:
value = RepeatedCompositeProperty(field_cdescriptor, field.message_type)
else:
value = RepeatedScalarProperty(field_cdescriptor)
elif field.cpp_type == _CPPTYPE_MESSAGE:
value = CompositeProperty(field_cdescriptor, field.message_type)
else:
value = ScalarProperty(field_cdescriptor)
setattr(cls, field.name, value)
# Attach a constant with the field number.
constant_name = field.name.upper() + '_FIELD_NUMBER'
setattr(cls, constant_name, field.number)
def Init(self, **kwargs):
"""Message constructor."""
cmessage = kwargs.pop('__cmessage', None)
if cmessage:
self._cmsg = cmessage
else:
self._cmsg = NewCMessage(message_descriptor.full_name)
# Keep a reference to the owner, as the owner keeps a reference to the
# underlying protocol buffer message.
owner = kwargs.pop('__owner', None)
if owner:
self._owner = owner
if message_descriptor.is_extendable:
self.Extensions = ExtensionDict(self)
else:
# Reference counting in the C++ code is broken and depends on
# the Extensions reference to keep this object alive during unit
# tests (see b/4856052). Remove this once b/4945904 is fixed.
self._HACK_REFCOUNTS = self
self._composite_fields = {}
for field_name, field_value in kwargs.iteritems():
field_cdescriptor = self.__descriptors.get(field_name, None)
if not field_cdescriptor:
raise ValueError('Protocol message has no "%s" field.' % field_name)
if field_cdescriptor.label == _LABEL_REPEATED:
if field_cdescriptor.cpp_type == _CPPTYPE_MESSAGE:
field_name = getattr(self, field_name)
for val in field_value:
field_name.add().MergeFrom(val)
else:
getattr(self, field_name).extend(field_value)
elif field_cdescriptor.cpp_type == _CPPTYPE_MESSAGE:
getattr(self, field_name).MergeFrom(field_value)
else:
setattr(self, field_name, field_value)
Init.__module__ = None
Init.__doc__ = None
cls.__init__ = Init
def _IsMessageSetExtension(field):
"""Checks if a field is a message set extension."""
return (field.is_extension and
field.containing_type.has_options and
field.containing_type.GetOptions().message_set_wire_format and
field.type == _TYPE_MESSAGE and
field.message_type == field.extension_scope and
field.label == _LABEL_OPTIONAL)
def _AddMessageMethods(message_descriptor, cls):
"""Adds the methods to a protocol message class."""
if message_descriptor.is_extendable:
def ClearExtension(self, extension):
self.Extensions.ClearExtension(extension)
def HasExtension(self, extension):
return self.Extensions.HasExtension(extension)
def HasField(self, field_name):
return self._cmsg.HasField(field_name)
def ClearField(self, field_name):
child_cmessage = None
if field_name in self._composite_fields:
child_field = self._composite_fields[field_name]
del self._composite_fields[field_name]
child_cdescriptor = self.__descriptors[field_name]
# TODO(anuraag): Support clearing repeated message fields as well.
if (child_cdescriptor.label != _LABEL_REPEATED and
child_cdescriptor.cpp_type == _CPPTYPE_MESSAGE):
child_field._owner = None
child_cmessage = child_field._cmsg
if child_cmessage is not None:
self._cmsg.ClearField(field_name, child_cmessage)
else:
self._cmsg.ClearField(field_name)
def Clear(self):
cmessages_to_release = []
for field_name, child_field in self._composite_fields.iteritems():
child_cdescriptor = self.__descriptors[field_name]
# TODO(anuraag): Support clearing repeated message fields as well.
if (child_cdescriptor.label != _LABEL_REPEATED and
child_cdescriptor.cpp_type == _CPPTYPE_MESSAGE):
child_field._owner = None
cmessages_to_release.append((child_cdescriptor, child_field._cmsg))
self._composite_fields.clear()
self._cmsg.Clear(cmessages_to_release)
def IsInitialized(self, errors=None):
if self._cmsg.IsInitialized():
return True
if errors is not None:
errors.extend(self.FindInitializationErrors());
return False
def SerializeToString(self):
if not self.IsInitialized():
raise message.EncodeError(
'Message %s is missing required fields: %s' % (
self._cmsg.full_name, ','.join(self.FindInitializationErrors())))
return self._cmsg.SerializeToString()
def SerializePartialToString(self):
return self._cmsg.SerializePartialToString()
def ParseFromString(self, serialized):
self.Clear()
self.MergeFromString(serialized)
def MergeFromString(self, serialized):
byte_size = self._cmsg.MergeFromString(serialized)
if byte_size < 0:
raise message.DecodeError('Unable to merge from string.')
return byte_size
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__, type(msg).__name__))
self._cmsg.MergeFrom(msg._cmsg)
def CopyFrom(self, msg):
self._cmsg.CopyFrom(msg._cmsg)
def ByteSize(self):
return self._cmsg.ByteSize()
def SetInParent(self):
return self._cmsg.SetInParent()
def ListFields(self):
all_fields = []
field_list = self._cmsg.ListFields()
fields_by_name = cls.DESCRIPTOR.fields_by_name
for is_extension, field_name in field_list:
if is_extension:
extension = cls._extensions_by_name[field_name]
all_fields.append((extension, self.Extensions[extension]))
else:
field_descriptor = fields_by_name[field_name]
all_fields.append(
(field_descriptor, getattr(self, field_name)))
all_fields.sort(key=lambda item: item[0].number)
return all_fields
def FindInitializationErrors(self):
return self._cmsg.FindInitializationErrors()
def __str__(self):
return str(self._cmsg)
def __eq__(self, other):
if self is other:
return True
if not isinstance(other, self.__class__):
return False
return self.ListFields() == other.ListFields()
def __ne__(self, other):
return not self == other
def __hash__(self):
raise TypeError('unhashable object')
def __unicode__(self):
# Lazy import to prevent circular import when text_format imports this file.
from google.protobuf import text_format
return text_format.MessageToString(self, as_utf8=True).decode('utf-8')
# Attach the local methods to the message class.
for key, value in locals().copy().iteritems():
if key not in ('key', 'value', '__builtins__', '__name__', '__doc__'):
setattr(cls, key, value)
# Static methods:
def RegisterExtension(extension_handle):
extension_handle.containing_type = cls.DESCRIPTOR
cls._extensions_by_name[extension_handle.full_name] = extension_handle
if _IsMessageSetExtension(extension_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(string):
msg = cls()
msg.MergeFromString(string)
return msg
cls.FromString = staticmethod(FromString)
def _AddPropertiesForExtensions(message_descriptor, cls):
"""Adds properties for all fields in this protocol message type."""
extension_dict = message_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)