400 lines
13 KiB
Python
400 lines
13 KiB
Python
|
# Protocol Buffers - Google's data interchange format
|
||
|
|
# Copyright 2008 Google Inc. All rights reserved.
|
||
|
|
#
|
||
|
|
# Use of this source code is governed by a BSD-style
|
||
|
|
# license that can be found in the LICENSE file or at
|
||
|
|
# https://developers.google.com/open-source/licenses/bsd
|
||
|
|
|
||
|
|
# TODO: We should just make these methods all "pure-virtual" and move
|
||
|
|
# all implementation out, into reflection.py for now.
|
||
|
|
|
||
|
|
|
||
|
|
"""Contains an abstract base class for protocol messages."""
|
||
|
|
|
||
|
|
__author__ = 'robinson@google.com (Will Robinson)'
|
||
|
|
|
||
|
|
class Error(Exception):
|
||
|
|
"""Base error type for this module."""
|
||
|
|
pass
|
||
|
|
|
||
|
|
|
||
|
|
class DecodeError(Error):
|
||
|
|
"""Exception raised when deserializing messages."""
|
||
|
|
pass
|
||
|
|
|
||
|
|
|
||
|
|
class EncodeError(Error):
|
||
|
|
"""Exception raised when serializing messages."""
|
||
|
|
pass
|
||
|
|
|
||
|
|
|
||
|
|
class Message(object):
|
||
|
|
|
||
|
|
"""Abstract base class for protocol messages.
|
||
|
|
|
||
|
|
Protocol message classes are almost always generated by the protocol
|
||
|
|
compiler. These generated types subclass Message and implement the methods
|
||
|
|
shown below.
|
||
|
|
"""
|
||
|
|
|
||
|
|
# TODO: Link to an HTML document here.
|
||
|
|
|
||
|
|
# TODO: Document that instances of this class will also
|
||
|
|
# have an Extensions attribute with __getitem__ and __setitem__.
|
||
|
|
# Again, not sure how to best convey this.
|
||
|
|
|
||
|
|
# TODO: Document these fields and methods.
|
||
|
|
|
||
|
|
__slots__ = []
|
||
|
|
|
||
|
|
#: The :class:`google.protobuf.Descriptor`
|
||
|
|
# for this message type.
|
||
|
|
DESCRIPTOR = None
|
||
|
|
|
||
|
|
def __deepcopy__(self, memo=None):
|
||
|
|
clone = type(self)()
|
||
|
|
clone.MergeFrom(self)
|
||
|
|
return clone
|
||
|
|
|
||
|
|
def __eq__(self, other_msg):
|
||
|
|
"""Recursively compares two messages by value and structure."""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def __ne__(self, other_msg):
|
||
|
|
# Can't just say self != other_msg, since that would infinitely recurse. :)
|
||
|
|
return not self == other_msg
|
||
|
|
|
||
|
|
def __hash__(self):
|
||
|
|
raise TypeError('unhashable object')
|
||
|
|
|
||
|
|
def __str__(self):
|
||
|
|
"""Outputs a human-readable representation of the message."""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def __unicode__(self):
|
||
|
|
"""Outputs a human-readable representation of the message."""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def MergeFrom(self, other_msg):
|
||
|
|
"""Merges the contents of the specified message into current message.
|
||
|
|
|
||
|
|
This method merges the contents of the specified message into the current
|
||
|
|
message. Singular fields that are set in the specified message overwrite
|
||
|
|
the corresponding fields in the current message. Repeated fields are
|
||
|
|
appended. Singular sub-messages and groups are recursively merged.
|
||
|
|
|
||
|
|
Args:
|
||
|
|
other_msg (Message): A message to merge into the current message.
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def CopyFrom(self, other_msg):
|
||
|
|
"""Copies the content of the specified message into the current message.
|
||
|
|
|
||
|
|
The method clears the current message and then merges the specified
|
||
|
|
message using MergeFrom.
|
||
|
|
|
||
|
|
Args:
|
||
|
|
other_msg (Message): A message to copy into the current one.
|
||
|
|
"""
|
||
|
|
if self is other_msg:
|
||
|
|
return
|
||
|
|
self.Clear()
|
||
|
|
self.MergeFrom(other_msg)
|
||
|
|
|
||
|
|
def Clear(self):
|
||
|
|
"""Clears all data that was set in the message."""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def SetInParent(self):
|
||
|
|
"""Mark this as present in the parent.
|
||
|
|
|
||
|
|
This normally happens automatically when you assign a field of a
|
||
|
|
sub-message, but sometimes you want to make the sub-message
|
||
|
|
present while keeping it empty. If you find yourself using this,
|
||
|
|
you may want to reconsider your design.
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def IsInitialized(self):
|
||
|
|
"""Checks if the message is initialized.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
bool: The method returns True if the message is initialized (i.e. all of
|
||
|
|
its required fields are set).
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
# TODO: MergeFromString() should probably return None and be
|
||
|
|
# implemented in terms of a helper that returns the # of bytes read. Our
|
||
|
|
# deserialization routines would use the helper when recursively
|
||
|
|
# deserializing, but the end user would almost always just want the no-return
|
||
|
|
# MergeFromString().
|
||
|
|
|
||
|
|
def MergeFromString(self, serialized):
|
||
|
|
"""Merges serialized protocol buffer data into this message.
|
||
|
|
|
||
|
|
When we find a field in `serialized` that is already present
|
||
|
|
in this message:
|
||
|
|
|
||
|
|
- If it's a "repeated" field, we append to the end of our list.
|
||
|
|
- Else, if it's a scalar, we overwrite our field.
|
||
|
|
- Else, (it's a nonrepeated composite), we recursively merge
|
||
|
|
into the existing composite.
|
||
|
|
|
||
|
|
Args:
|
||
|
|
serialized (bytes): Any object that allows us to call
|
||
|
|
``memoryview(serialized)`` to access a string of bytes using the
|
||
|
|
buffer interface.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
int: The number of bytes read from `serialized`.
|
||
|
|
For non-group messages, this will always be `len(serialized)`,
|
||
|
|
but for messages which are actually groups, this will
|
||
|
|
generally be less than `len(serialized)`, since we must
|
||
|
|
stop when we reach an ``END_GROUP`` tag. Note that if
|
||
|
|
we *do* stop because of an ``END_GROUP`` tag, the number
|
||
|
|
of bytes returned does not include the bytes
|
||
|
|
for the ``END_GROUP`` tag information.
|
||
|
|
|
||
|
|
Raises:
|
||
|
|
DecodeError: if the input cannot be parsed.
|
||
|
|
"""
|
||
|
|
# TODO: Document handling of unknown fields.
|
||
|
|
# TODO: When we switch to a helper, this will return None.
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def ParseFromString(self, serialized):
|
||
|
|
"""Parse serialized protocol buffer data in binary form into this message.
|
||
|
|
|
||
|
|
Like :func:`MergeFromString()`, except we clear the object first.
|
||
|
|
|
||
|
|
Raises:
|
||
|
|
message.DecodeError if the input cannot be parsed.
|
||
|
|
"""
|
||
|
|
self.Clear()
|
||
|
|
return self.MergeFromString(serialized)
|
||
|
|
|
||
|
|
def SerializeToString(self, **kwargs):
|
||
|
|
"""Serializes the protocol message to a binary string.
|
||
|
|
|
||
|
|
Keyword Args:
|
||
|
|
deterministic (bool): If true, requests deterministic serialization
|
||
|
|
of the protobuf, with predictable ordering of map keys.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
A binary string representation of the message if all of the required
|
||
|
|
fields in the message are set (i.e. the message is initialized).
|
||
|
|
|
||
|
|
Raises:
|
||
|
|
EncodeError: if the message isn't initialized (see :func:`IsInitialized`).
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def SerializePartialToString(self, **kwargs):
|
||
|
|
"""Serializes the protocol message to a binary string.
|
||
|
|
|
||
|
|
This method is similar to SerializeToString but doesn't check if the
|
||
|
|
message is initialized.
|
||
|
|
|
||
|
|
Keyword Args:
|
||
|
|
deterministic (bool): If true, requests deterministic serialization
|
||
|
|
of the protobuf, with predictable ordering of map keys.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
bytes: A serialized representation of the partial message.
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
# TODO: Decide whether we like these better
|
||
|
|
# than auto-generated has_foo() and clear_foo() methods
|
||
|
|
# on the instances themselves. This way is less consistent
|
||
|
|
# with C++, but it makes reflection-type access easier and
|
||
|
|
# reduces the number of magically autogenerated things.
|
||
|
|
#
|
||
|
|
# TODO: Be sure to document (and test) exactly
|
||
|
|
# which field names are accepted here. Are we case-sensitive?
|
||
|
|
# What do we do with fields that share names with Python keywords
|
||
|
|
# like 'lambda' and 'yield'?
|
||
|
|
#
|
||
|
|
# nnorwitz says:
|
||
|
|
# """
|
||
|
|
# Typically (in python), an underscore is appended to names that are
|
||
|
|
# keywords. So they would become lambda_ or yield_.
|
||
|
|
# """
|
||
|
|
def ListFields(self):
|
||
|
|
"""Returns a list of (FieldDescriptor, value) tuples for present fields.
|
||
|
|
|
||
|
|
A message field is non-empty if HasField() would return true. A singular
|
||
|
|
primitive field is non-empty if HasField() would return true in proto2 or it
|
||
|
|
is non zero in proto3. A repeated field is non-empty if it contains at least
|
||
|
|
one element. The fields are ordered by field number.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
list[tuple(FieldDescriptor, value)]: field descriptors and values
|
||
|
|
for all fields in the message which are not empty. The values vary by
|
||
|
|
field type.
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def HasField(self, field_name):
|
||
|
|
"""Checks if a certain field is set for the message.
|
||
|
|
|
||
|
|
For a oneof group, checks if any field inside is set. Note that if the
|
||
|
|
field_name is not defined in the message descriptor, :exc:`ValueError` will
|
||
|
|
be raised.
|
||
|
|
|
||
|
|
Args:
|
||
|
|
field_name (str): The name of the field to check for presence.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
bool: Whether a value has been set for the named field.
|
||
|
|
|
||
|
|
Raises:
|
||
|
|
ValueError: if the `field_name` is not a member of this message.
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def ClearField(self, field_name):
|
||
|
|
"""Clears the contents of a given field.
|
||
|
|
|
||
|
|
Inside a oneof group, clears the field set. If the name neither refers to a
|
||
|
|
defined field or oneof group, :exc:`ValueError` is raised.
|
||
|
|
|
||
|
|
Args:
|
||
|
|
field_name (str): The name of the field to check for presence.
|
||
|
|
|
||
|
|
Raises:
|
||
|
|
ValueError: if the `field_name` is not a member of this message.
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def WhichOneof(self, oneof_group):
|
||
|
|
"""Returns the name of the field that is set inside a oneof group.
|
||
|
|
|
||
|
|
If no field is set, returns None.
|
||
|
|
|
||
|
|
Args:
|
||
|
|
oneof_group (str): the name of the oneof group to check.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
str or None: The name of the group that is set, or None.
|
||
|
|
|
||
|
|
Raises:
|
||
|
|
ValueError: no group with the given name exists
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def HasExtension(self, field_descriptor):
|
||
|
|
"""Checks if a certain extension is present for this message.
|
||
|
|
|
||
|
|
Extensions are retrieved using the :attr:`Extensions` mapping (if present).
|
||
|
|
|
||
|
|
Args:
|
||
|
|
field_descriptor: The field descriptor for the extension to check.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
bool: Whether the extension is present for this message.
|
||
|
|
|
||
|
|
Raises:
|
||
|
|
KeyError: if the extension is repeated. Similar to repeated fields,
|
||
|
|
there is no separate notion of presence: a "not present" repeated
|
||
|
|
extension is an empty list.
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def ClearExtension(self, field_descriptor):
|
||
|
|
"""Clears the contents of a given extension.
|
||
|
|
|
||
|
|
Args:
|
||
|
|
field_descriptor: The field descriptor for the extension to clear.
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def UnknownFields(self):
|
||
|
|
"""Returns the UnknownFieldSet.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
UnknownFieldSet: The unknown fields stored in this message.
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def DiscardUnknownFields(self):
|
||
|
|
"""Clears all fields in the :class:`UnknownFieldSet`.
|
||
|
|
|
||
|
|
This operation is recursive for nested message.
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def ByteSize(self):
|
||
|
|
"""Returns the serialized size of this message.
|
||
|
|
|
||
|
|
Recursively calls ByteSize() on all contained messages.
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
int: The number of bytes required to serialize this message.
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
@classmethod
|
||
|
|
def FromString(cls, s):
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
# TODO: Remove it in OSS
|
||
|
|
@staticmethod
|
||
|
|
def RegisterExtension(field_descriptor):
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def _SetListener(self, message_listener):
|
||
|
|
"""Internal method used by the protocol message implementation.
|
||
|
|
Clients should not call this directly.
|
||
|
|
|
||
|
|
Sets a listener that this message will call on certain state transitions.
|
||
|
|
|
||
|
|
The purpose of this method is to register back-edges from children to
|
||
|
|
parents at runtime, for the purpose of setting "has" bits and
|
||
|
|
byte-size-dirty bits in the parent and ancestor objects whenever a child or
|
||
|
|
descendant object is modified.
|
||
|
|
|
||
|
|
If the client wants to disconnect this Message from the object tree, she
|
||
|
|
explicitly sets callback to None.
|
||
|
|
|
||
|
|
If message_listener is None, unregisters any existing listener. Otherwise,
|
||
|
|
message_listener must implement the MessageListener interface in
|
||
|
|
internal/message_listener.py, and we discard any listener registered
|
||
|
|
via a previous _SetListener() call.
|
||
|
|
"""
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def __getstate__(self):
|
||
|
|
"""Support the pickle protocol."""
|
||
|
|
return dict(serialized=self.SerializePartialToString())
|
||
|
|
|
||
|
|
def __setstate__(self, state):
|
||
|
|
"""Support the pickle protocol."""
|
||
|
|
self.__init__()
|
||
|
|
serialized = state['serialized']
|
||
|
|
# On Python 3, using encoding='latin1' is required for unpickling
|
||
|
|
# protos pickled by Python 2.
|
||
|
|
if not isinstance(serialized, bytes):
|
||
|
|
serialized = serialized.encode('latin1')
|
||
|
|
self.ParseFromString(serialized)
|
||
|
|
|
||
|
|
def __reduce__(self):
|
||
|
|
message_descriptor = self.DESCRIPTOR
|
||
|
|
if message_descriptor.containing_type is None:
|
||
|
|
return type(self), (), self.__getstate__()
|
||
|
|
# the message type must be nested.
|
||
|
|
# Python does not pickle nested classes; use the symbol_database on the
|
||
|
|
# receiving end.
|
||
|
|
container = message_descriptor
|
||
|
|
return (_InternalConstructMessage, (container.full_name,),
|
||
|
|
self.__getstate__())
|
||
|
|
|
||
|
|
|
||
|
|
def _InternalConstructMessage(full_name):
|
||
|
|
"""Constructs a nested message."""
|
||
|
|
from google.protobuf import symbol_database # pylint:disable=g-import-not-at-top
|
||
|
|
|
||
|
|
return symbol_database.Default().GetSymbol(full_name)()
|