Files
bumble_mirror/bumble/gatt_adapters.py
2025-12-29 19:28:45 -08:00

365 lines
13 KiB
Python

# Copyright 2025 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# -----------------------------------------------------------------------------
# GATT - Type Adapters
# -----------------------------------------------------------------------------
# -----------------------------------------------------------------------------
# Imports
# -----------------------------------------------------------------------------
from __future__ import annotations
import struct
from typing import Any, Callable, Generic, Iterable, Literal, Optional, TypeVar
from bumble import utils
from bumble.core import InvalidOperationError
from bumble.gatt import Characteristic
from bumble.gatt_client import CharacteristicProxy
# -----------------------------------------------------------------------------
# Typing
# -----------------------------------------------------------------------------
_T = TypeVar('_T')
_T2 = TypeVar('_T2', bound=utils.ByteSerializable)
_T3 = TypeVar('_T3', bound=utils.IntConvertible)
# -----------------------------------------------------------------------------
class CharacteristicAdapter(Characteristic, Generic[_T]):
'''Base class for GATT Characteristic adapters.'''
def __init__(self, characteristic: Characteristic) -> None:
super().__init__(
characteristic.uuid,
characteristic.properties,
characteristic.permissions,
characteristic.value,
characteristic.descriptors,
)
# -----------------------------------------------------------------------------
class CharacteristicProxyAdapter(CharacteristicProxy[_T]):
'''Base class for GATT CharacteristicProxy adapters.'''
def __init__(self, characteristic_proxy: CharacteristicProxy):
super().__init__(
characteristic_proxy.client,
characteristic_proxy.handle,
characteristic_proxy.end_group_handle,
characteristic_proxy.uuid,
characteristic_proxy.properties,
)
# -----------------------------------------------------------------------------
class DelegatedCharacteristicAdapter(CharacteristicAdapter[_T]):
'''
Adapter that converts bytes values using an encode and/or a decode function.
'''
def __init__(
self,
characteristic: Characteristic,
encode: Optional[Callable[[_T], bytes]] = None,
decode: Optional[Callable[[bytes], _T]] = None,
):
super().__init__(characteristic)
self.encode = encode
self.decode = decode
def encode_value(self, value: _T) -> bytes:
if self.encode is None:
raise InvalidOperationError('delegated adapter does not have an encoder')
return self.encode(value)
def decode_value(self, value: bytes) -> _T:
if self.decode is None:
raise InvalidOperationError('delegate adapter does not have a decoder')
return self.decode(value)
# -----------------------------------------------------------------------------
class DelegatedCharacteristicProxyAdapter(CharacteristicProxyAdapter[_T]):
'''
Adapter that converts bytes values using an encode and a decode function.
'''
def __init__(
self,
characteristic_proxy: CharacteristicProxy,
encode: Optional[Callable[[_T], bytes]] = None,
decode: Optional[Callable[[bytes], _T]] = None,
):
super().__init__(characteristic_proxy)
self.encode = encode
self.decode = decode
def encode_value(self, value: _T) -> bytes:
if self.encode is None:
raise InvalidOperationError('delegated adapter does not have an encoder')
return self.encode(value)
def decode_value(self, value: bytes) -> _T:
if self.decode is None:
raise InvalidOperationError('delegate adapter does not have a decoder')
return self.decode(value)
# -----------------------------------------------------------------------------
class PackedCharacteristicAdapter(CharacteristicAdapter):
'''
Adapter that packs/unpacks characteristic values according to a standard
Python `struct` format.
For formats with a single value, the adapted `read_value` and `write_value`
methods return/accept single values. For formats with multiple values,
they return/accept a tuple with the same number of elements as is required for
the format.
'''
def __init__(self, characteristic: Characteristic, pack_format: str) -> None:
super().__init__(characteristic)
self.struct = struct.Struct(pack_format)
def pack(self, *values) -> bytes:
return self.struct.pack(*values)
def unpack(self, buffer: bytes) -> tuple:
return self.struct.unpack(buffer)
def encode_value(self, value: Any) -> bytes:
return self.pack(*value if isinstance(value, tuple) else (value,))
def decode_value(self, value: bytes) -> Any:
unpacked = self.unpack(value)
return unpacked[0] if len(unpacked) == 1 else unpacked
# -----------------------------------------------------------------------------
class PackedCharacteristicProxyAdapter(CharacteristicProxyAdapter):
'''
Adapter that packs/unpacks characteristic values according to a standard
Python `struct` format.
For formats with a single value, the adapted `read_value` and `write_value`
methods return/accept single values. For formats with multiple values,
they return/accept a tuple with the same number of elements as is required for
the format.
'''
def __init__(self, characteristic_proxy, pack_format):
super().__init__(characteristic_proxy)
self.struct = struct.Struct(pack_format)
def pack(self, *values) -> bytes:
return self.struct.pack(*values)
def unpack(self, buffer: bytes) -> tuple:
return self.struct.unpack(buffer)
def encode_value(self, value: Any) -> bytes:
return self.pack(*value if isinstance(value, tuple) else (value,))
def decode_value(self, value: bytes) -> Any:
unpacked = self.unpack(value)
return unpacked[0] if len(unpacked) == 1 else unpacked
# -----------------------------------------------------------------------------
class MappedCharacteristicAdapter(PackedCharacteristicAdapter):
'''
Adapter that packs/unpacks characteristic values according to a standard
Python `struct` format.
The adapted `read_value` and `write_value` methods return/accept a dictionary which
is packed/unpacked according to format, with the arguments extracted from the
dictionary by key, in the same order as they occur in the `keys` parameter.
'''
def __init__(
self, characteristic: Characteristic, pack_format: str, keys: Iterable[str]
) -> None:
super().__init__(characteristic, pack_format)
self.keys = keys
# pylint: disable=arguments-differ
def pack(self, values) -> bytes:
return super().pack(*(values[key] for key in self.keys))
def unpack(self, buffer: bytes) -> Any:
return dict(zip(self.keys, super().unpack(buffer)))
# -----------------------------------------------------------------------------
class MappedCharacteristicProxyAdapter(PackedCharacteristicProxyAdapter):
'''
Adapter that packs/unpacks characteristic values according to a standard
Python `struct` format.
The adapted `read_value` and `write_value` methods return/accept a dictionary which
is packed/unpacked according to format, with the arguments extracted from the
dictionary by key, in the same order as they occur in the `keys` parameter.
'''
def __init__(
self,
characteristic_proxy: CharacteristicProxy,
pack_format: str,
keys: Iterable[str],
) -> None:
super().__init__(characteristic_proxy, pack_format)
self.keys = keys
# pylint: disable=arguments-differ
def pack(self, values) -> bytes:
return super().pack(*(values[key] for key in self.keys))
def unpack(self, buffer: bytes) -> Any:
return dict(zip(self.keys, super().unpack(buffer)))
# -----------------------------------------------------------------------------
class UTF8CharacteristicAdapter(CharacteristicAdapter[str]):
'''
Adapter that converts strings to/from bytes using UTF-8 encoding
'''
def encode_value(self, value: str) -> bytes:
return value.encode('utf-8')
def decode_value(self, value: bytes) -> str:
return value.decode('utf-8')
# -----------------------------------------------------------------------------
class UTF8CharacteristicProxyAdapter(CharacteristicProxyAdapter[str]):
'''
Adapter that converts strings to/from bytes using UTF-8 encoding
'''
def encode_value(self, value: str) -> bytes:
return value.encode('utf-8')
def decode_value(self, value: bytes) -> str:
return value.decode('utf-8')
# -----------------------------------------------------------------------------
class SerializableCharacteristicAdapter(CharacteristicAdapter[_T2]):
'''
Adapter that converts any class to/from bytes using the class'
`to_bytes` and `__bytes__` methods, respectively.
'''
def __init__(self, characteristic: Characteristic, cls: type[_T2]) -> None:
super().__init__(characteristic)
self.cls = cls
def encode_value(self, value: _T2) -> bytes:
return bytes(value)
def decode_value(self, value: bytes) -> _T2:
return self.cls.from_bytes(value)
# -----------------------------------------------------------------------------
class SerializableCharacteristicProxyAdapter(CharacteristicProxyAdapter[_T2]):
'''
Adapter that converts any class to/from bytes using the class'
`to_bytes` and `__bytes__` methods, respectively.
'''
def __init__(
self, characteristic_proxy: CharacteristicProxy, cls: type[_T2]
) -> None:
super().__init__(characteristic_proxy)
self.cls = cls
def encode_value(self, value: _T2) -> bytes:
return bytes(value)
def decode_value(self, value: bytes) -> _T2:
return self.cls.from_bytes(value)
# -----------------------------------------------------------------------------
class EnumCharacteristicAdapter(CharacteristicAdapter[_T3]):
'''
Adapter that converts int-enum-like classes to/from bytes using the class'
`int().to_bytes()` and `from_bytes()` methods, respectively.
'''
def __init__(
self,
characteristic: Characteristic,
cls: type[_T3],
length: int,
byteorder: Literal['little', 'big'] = 'little',
):
"""
Initialize an instance.
Params:
characteristic: the Characteristic to adapt to/from
cls: the class to/from which to convert integer values
length: number of bytes used to represent integer values
byteorder: byte order of the byte representation of integers.
"""
super().__init__(characteristic)
self.cls = cls
self.length = length
self.byteorder = byteorder
def encode_value(self, value: _T3) -> bytes:
return int(value).to_bytes(self.length, self.byteorder)
def decode_value(self, value: bytes) -> _T3:
int_value = int.from_bytes(value, self.byteorder)
return self.cls(int_value)
# -----------------------------------------------------------------------------
class EnumCharacteristicProxyAdapter(CharacteristicProxyAdapter[_T3]):
'''
Adapter that converts int-enum-like classes to/from bytes using the class'
`int().to_bytes()` and `from_bytes()` methods, respectively.
'''
def __init__(
self,
characteristic_proxy: CharacteristicProxy,
cls: type[_T3],
length: int,
byteorder: Literal['little', 'big'] = 'little',
):
"""
Initialize an instance.
Params:
characteristic_proxy: the CharacteristicProxy to adapt to/from
cls: the class to/from which to convert integer values
length: number of bytes used to represent integer values
byteorder: byte order of the byte representation of integers.
"""
super().__init__(characteristic_proxy)
self.cls = cls
self.length = length
self.byteorder = byteorder
def encode_value(self, value: _T3) -> bytes:
return int(value).to_bytes(self.length, self.byteorder)
def decode_value(self, value: bytes) -> _T3:
int_value = int.from_bytes(value, self.byteorder)
return self.cls(int_value)