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# Copyright 2024 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
"""LE Audio - Published Audio Capabilities Service"""
# -----------------------------------------------------------------------------
# Imports
# -----------------------------------------------------------------------------
from __future__ import annotations
import dataclasses
import logging
import struct
from collections.abc import Sequence
from bumble import gatt, gatt_adapters, gatt_client, hci
from bumble.profiles import le_audio
from bumble.profiles.bap import AudioLocation, CodecSpecificCapabilities, ContextType
# -----------------------------------------------------------------------------
# Logging
# -----------------------------------------------------------------------------
logger = logging.getLogger(__name__)
# -----------------------------------------------------------------------------
@dataclasses.dataclass
class PacRecord:
'''Published Audio Capabilities Service, Table 3.2/3.4.'''
coding_format: hci.CodingFormat
codec_specific_capabilities: CodecSpecificCapabilities | bytes
metadata: le_audio.Metadata = dataclasses.field(default_factory=le_audio.Metadata)
@classmethod
def from_bytes(cls, data: bytes) -> PacRecord:
offset, coding_format = hci.CodingFormat.parse_from_bytes(data, 0)
codec_specific_capabilities_size = data[offset]
offset += 1
codec_specific_capabilities_bytes = data[
offset : offset + codec_specific_capabilities_size
]
offset += codec_specific_capabilities_size
metadata_size = data[offset]
offset += 1
metadata = le_audio.Metadata.from_bytes(data[offset : offset + metadata_size])
codec_specific_capabilities: CodecSpecificCapabilities | bytes
if coding_format.codec_id == hci.CodecID.VENDOR_SPECIFIC:
codec_specific_capabilities = codec_specific_capabilities_bytes
else:
codec_specific_capabilities = CodecSpecificCapabilities.from_bytes(
codec_specific_capabilities_bytes
)
return PacRecord(
coding_format=coding_format,
codec_specific_capabilities=codec_specific_capabilities,
metadata=metadata,
)
@classmethod
def list_from_bytes(cls, data: bytes) -> list[PacRecord]:
"""Parse a serialized list of records preceded by a one byte list length."""
record_count = data[0]
records = []
offset = 1
for _ in range(record_count):
record = PacRecord.from_bytes(data[offset:])
offset += len(bytes(record))
records.append(record)
return records
def __bytes__(self) -> bytes:
capabilities_bytes = bytes(self.codec_specific_capabilities)
metadata_bytes = bytes(self.metadata)
return (
bytes(self.coding_format)
+ bytes([len(capabilities_bytes)])
+ capabilities_bytes
+ bytes([len(metadata_bytes)])
+ metadata_bytes
)
# -----------------------------------------------------------------------------
# Server
# -----------------------------------------------------------------------------
class PublishedAudioCapabilitiesService(gatt.TemplateService):
UUID = gatt.GATT_PUBLISHED_AUDIO_CAPABILITIES_SERVICE
sink_pac: gatt.Characteristic[bytes] | None
sink_audio_locations: gatt.Characteristic[bytes] | None
source_pac: gatt.Characteristic[bytes] | None
source_audio_locations: gatt.Characteristic[bytes] | None
available_audio_contexts: gatt.Characteristic[bytes]
supported_audio_contexts: gatt.Characteristic[bytes]
def __init__(
self,
supported_source_context: ContextType,
supported_sink_context: ContextType,
available_source_context: ContextType,
available_sink_context: ContextType,
sink_pac: Sequence[PacRecord] = (),
sink_audio_locations: AudioLocation | None = None,
source_pac: Sequence[PacRecord] = (),
source_audio_locations: AudioLocation | None = None,
) -> None:
characteristics = []
self.supported_audio_contexts = gatt.Characteristic(
uuid=gatt.GATT_SUPPORTED_AUDIO_CONTEXTS_CHARACTERISTIC,
properties=gatt.Characteristic.Properties.READ,
permissions=gatt.Characteristic.Permissions.READABLE,
value=struct.pack('<HH', supported_sink_context, supported_source_context),
)
characteristics.append(self.supported_audio_contexts)
self.available_audio_contexts = gatt.Characteristic(
uuid=gatt.GATT_AVAILABLE_AUDIO_CONTEXTS_CHARACTERISTIC,
properties=gatt.Characteristic.Properties.READ
| gatt.Characteristic.Properties.NOTIFY,
permissions=gatt.Characteristic.Permissions.READABLE,
value=struct.pack('<HH', available_sink_context, available_source_context),
)
characteristics.append(self.available_audio_contexts)
if sink_pac:
self.sink_pac = gatt.Characteristic(
uuid=gatt.GATT_SINK_PAC_CHARACTERISTIC,
properties=gatt.Characteristic.Properties.READ,
permissions=gatt.Characteristic.Permissions.READABLE,
value=bytes([len(sink_pac)]) + b''.join(map(bytes, sink_pac)),
)
characteristics.append(self.sink_pac)
if sink_audio_locations is not None:
self.sink_audio_locations = gatt.Characteristic(
uuid=gatt.GATT_SINK_AUDIO_LOCATION_CHARACTERISTIC,
properties=gatt.Characteristic.Properties.READ,
permissions=gatt.Characteristic.Permissions.READABLE,
value=struct.pack('<I', sink_audio_locations),
)
characteristics.append(self.sink_audio_locations)
if source_pac:
self.source_pac = gatt.Characteristic(
uuid=gatt.GATT_SOURCE_PAC_CHARACTERISTIC,
properties=gatt.Characteristic.Properties.READ,
permissions=gatt.Characteristic.Permissions.READABLE,
value=bytes([len(source_pac)]) + b''.join(map(bytes, source_pac)),
)
characteristics.append(self.source_pac)
if source_audio_locations is not None:
self.source_audio_locations = gatt.Characteristic(
uuid=gatt.GATT_SOURCE_AUDIO_LOCATION_CHARACTERISTIC,
properties=gatt.Characteristic.Properties.READ,
permissions=gatt.Characteristic.Permissions.READABLE,
value=struct.pack('<I', source_audio_locations),
)
characteristics.append(self.source_audio_locations)
super().__init__(characteristics)
# -----------------------------------------------------------------------------
# Client
# -----------------------------------------------------------------------------
class PublishedAudioCapabilitiesServiceProxy(gatt_client.ProfileServiceProxy):
SERVICE_CLASS = PublishedAudioCapabilitiesService
sink_pac: gatt_client.CharacteristicProxy[list[PacRecord]] | None = None
sink_audio_locations: gatt_client.CharacteristicProxy[AudioLocation] | None = None
source_pac: gatt_client.CharacteristicProxy[list[PacRecord]] | None = None
source_audio_locations: gatt_client.CharacteristicProxy[AudioLocation] | None = None
available_audio_contexts: gatt_client.CharacteristicProxy[tuple[ContextType, ...]]
supported_audio_contexts: gatt_client.CharacteristicProxy[tuple[ContextType, ...]]
def __init__(self, service_proxy: gatt_client.ServiceProxy):
self.service_proxy = service_proxy
self.available_audio_contexts = (
gatt_adapters.DelegatedCharacteristicProxyAdapter(
service_proxy.get_required_characteristic_by_uuid(
gatt.GATT_AVAILABLE_AUDIO_CONTEXTS_CHARACTERISTIC
),
decode=lambda x: tuple(map(ContextType, struct.unpack('<HH', x))),
)
)
self.supported_audio_contexts = (
gatt_adapters.DelegatedCharacteristicProxyAdapter(
service_proxy.get_required_characteristic_by_uuid(
gatt.GATT_SUPPORTED_AUDIO_CONTEXTS_CHARACTERISTIC
),
decode=lambda x: tuple(map(ContextType, struct.unpack('<HH', x))),
)
)
if characteristics := service_proxy.get_characteristics_by_uuid(
gatt.GATT_SINK_PAC_CHARACTERISTIC
):
self.sink_pac = gatt_adapters.DelegatedCharacteristicProxyAdapter(
characteristics[0],
decode=PacRecord.list_from_bytes,
)
if characteristics := service_proxy.get_characteristics_by_uuid(
gatt.GATT_SOURCE_PAC_CHARACTERISTIC
):
self.source_pac = gatt_adapters.DelegatedCharacteristicProxyAdapter(
characteristics[0],
decode=PacRecord.list_from_bytes,
)
if characteristics := service_proxy.get_characteristics_by_uuid(
gatt.GATT_SINK_AUDIO_LOCATION_CHARACTERISTIC
):
self.sink_audio_locations = (
gatt_adapters.DelegatedCharacteristicProxyAdapter(
characteristics[0],
decode=lambda x: AudioLocation(struct.unpack('<I', x)[0]),
)
)
if characteristics := service_proxy.get_characteristics_by_uuid(
gatt.GATT_SOURCE_AUDIO_LOCATION_CHARACTERISTIC
):
self.source_audio_locations = (
gatt_adapters.DelegatedCharacteristicProxyAdapter(
characteristics[0],
decode=lambda x: AudioLocation(struct.unpack('<I', x)[0]),
)
)
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