Current File : //lib/python2.7/site-packages/google/protobuf/internal/python_message.py
# 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.
# 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)'
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
import copy_reg
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 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 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
def NewMessage(bases, descriptor, dictionary):
_AddClassAttributesForNestedExtensions(descriptor, dictionary)
_AddSlots(descriptor, dictionary)
return bases
def InitMessage(descriptor, cls):
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))
# Attach stuff to each FieldDescriptor for quick lookup later on.
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)
copy_reg.pickle(cls, lambda obj: (cls, (), obj.__getstate__()))
# 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__']
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.
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 _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 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.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):
# 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 _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 = len(kwargs) > 0
self._fields = {}
# _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.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:
setattr(self, field_name, 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
valid_values = set()
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
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.
"""
# TODO(robinson): Remove duplication with similar method
# for non-repeated scalars.
proto_field_name = field.name
property_name = _PropertyName(proto_field_name)
# TODO(komarek): Can anyone explain to me why we cache the message_type this
# way, instead of referring to field.message_type inside of getter(self)?
# What if someone sets message_type later on (which makes for simpler
# dyanmic proto descriptor and class creation code).
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() # use field.message_type?
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
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)
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]
# 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._unknown_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
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 _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 _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.
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):
# 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()
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)
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:
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
unknown_field_list = self._unknown_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:
value_start_pos = new_pos
new_pos = local_SkipField(buffer, new_pos, end, tag_bytes)
if new_pos == -1:
return pos
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)
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):
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__))
assert msg is not self
self._Modified()
fields = self._fields
for field, value in msg._fields.iteritems():
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 msg._unknown_fields:
if not self._unknown_fields:
self._unknown_fields = []
self._unknown_fields.extend(msg._unknown_fields)
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)
_AddUnicodeMethod(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.
"""
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.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)
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