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trezor-firmware/python/src/trezorlib/mapping.py
matejcik a58823cc0c refactor(python): rework trezorlib protobuf codec
API-compatibility with the original one is retained.

Now that we don't need to keep code parity with core, we could do some
changes that make life easier.

All generated classes are now in one file. This makes github diffs more
readable, at the cost of somewhat complicating inspecting individual
classes; however, that is something we shouldn't be doing anyway.

Enums are now implemented as enum.IntEnum.

The original class-level FIELDS member was restored.

Each field is now defined via protobuf.Field, which is easier to work
with in the codec, AND we're not stuffing defaults and flags into the
same field.
2021-06-08 09:55:19 +02:00

75 lines
2.2 KiB
Python

# This file is part of the Trezor project.
#
# Copyright (C) 2012-2019 SatoshiLabs and contributors
#
# This library is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License version 3
# as published by the Free Software Foundation.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the License along with this library.
# If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
import io
from typing import Tuple
from . import messages, protobuf
map_type_to_class = {}
map_class_to_type = {}
def build_map():
for entry in messages.MessageType:
msg_class = getattr(messages, entry.name, None)
if msg_class is None:
raise ValueError(
f"Implementation of protobuf message '{entry.name}' is missing"
)
if msg_class.MESSAGE_WIRE_TYPE != entry.value:
raise ValueError(
f"Inconsistent wire type and MessageType record for '{entry.name}'"
)
register_message(msg_class)
def register_message(msg_class):
if msg_class.MESSAGE_WIRE_TYPE in map_type_to_class:
raise Exception(
"Message for wire type %s is already registered by %s"
% (msg_class.MESSAGE_WIRE_TYPE, get_class(msg_class.MESSAGE_WIRE_TYPE))
)
map_class_to_type[msg_class] = msg_class.MESSAGE_WIRE_TYPE
map_type_to_class[msg_class.MESSAGE_WIRE_TYPE] = msg_class
def get_type(msg):
return map_class_to_type[msg.__class__]
def get_class(t):
return map_type_to_class[t]
def encode(msg: protobuf.MessageType) -> Tuple[int, bytes]:
message_type = msg.MESSAGE_WIRE_TYPE
buf = io.BytesIO()
protobuf.dump_message(buf, msg)
return message_type, buf.getvalue()
def decode(message_type: int, message_bytes: bytes) -> protobuf.MessageType:
cls = get_class(message_type)
buf = io.BytesIO(message_bytes)
return protobuf.load_message(buf, cls)
build_map()