# Protocol Buffers - Google's data interchange format
# Copyright 2008 Google Inc. All rights reserved.
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# * 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
# * 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.
# TODO(robinson): 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__ = 'email@example.com (Will Robinson)'
class Error(Exception): pass
class DecodeError(Error): pass
class EncodeError(Error): pass
"""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
TODO(robinson): Link to an HTML document here.
TODO(robinson): 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(robinson): Document that the class must also have a static
Not sure how to best express at this point.
# TODO(robinson): Document these fields and methods.
__slots__ = 
DESCRIPTOR = None
def __deepcopy__(self, memo=None):
clone = type(self)()
def __eq__(self, other_msg):
def __ne__(self, other_msg):
# Can't just say self != other_msg, since that would infinitely recurse. :)
return not self == other_msg
raise TypeError('unhashable object')
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.
other_msg: Message to merge into the current message.
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.
other_msg: Message to copy into the current one.
if self is other_msg:
"""Clears all data that was set in the message."""
"""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."""
"""Checks if the message is initialized.
The method returns True if the message is initialized (i.e. all of its
required fields are set).
# TODO(robinson): 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
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.
TODO(robinson): Document handling of unknown fields.
serialized: Any object that allows us to call buffer(serialized)
to access a string of bytes using the buffer interface.
TODO(robinson): When we switch to a helper, this will return None.
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.
def ParseFromString(self, serialized):
"""Like MergeFromString(), except we clear the object first."""
"""Serializes the protocol message to a binary string.
A binary string representation of the message if all of the required
fields in the message are set (i.e. the message is initialized).
message.EncodeError if the message isn't initialized.
"""Serializes the protocol message to a binary string.
This method is similar to SerializeToString but doesn't check if the
message is initialized.
A string representation of the partial message.
# TODO(robinson): 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(robinson): 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_.
"""Returns a list of (FieldDescriptor, value) tuples for all
fields in the message which are not empty. A singular field is non-empty
if HasField() would return true, and a repeated field is non-empty if
it contains at least one element. The fields are ordered by field
def HasField(self, field_name):
def ClearField(self, field_name):
def HasExtension(self, extension_handle):
def ClearExtension(self, extension_handle):
"""Returns the serialized size of this message.
Recursively calls ByteSize() on all contained messages.
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.