Add Volume Control Service

bumble/profiles/vcp.py

@@ -0,0 +1,228 @@
+# Copyright 2021-2024 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 the specific language governing permissions and
+# limitations under the License.
+
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+from __future__ import annotations
+import enum
+
+from bumble import att
+from bumble import device
+from bumble import gatt
+from bumble import gatt_client
+
+from typing import Optional
+
+# -----------------------------------------------------------------------------
+# Constants
+# -----------------------------------------------------------------------------
+
+MIN_VOLUME = 0
+MAX_VOLUME = 255
+
+
+class ErrorCode(enum.IntEnum):
+    '''
+    See Volume Control Service 1.6. Application error codes.
+    '''
+
+    INVALID_CHANGE_COUNTER = 0x80
+    OPCODE_NOT_SUPPORTED = 0x81
+
+
+class VolumeFlags(enum.IntFlag):
+    '''
+    See Volume Control Service 3.3. Volume Flags.
+    '''
+
+    VOLUME_SETTING_PERSISTED = 0x01
+    # RFU
+
+
+class VolumeControlPointOpcode(enum.IntEnum):
+    '''
+    See Volume Control Service Table 3.3: Volume Control Point procedure requirements.
+    '''
+
+    # fmt: off
+    RELATIVE_VOLUME_DOWN        = 0x00
+    RELATIVE_VOLUME_UP          = 0x01
+    UNMUTE_RELATIVE_VOLUME_DOWN = 0x02
+    UNMUTE_RELATIVE_VOLUME_UP   = 0x03
+    SET_ABSOLUTE_VOLUME         = 0x04
+    UNMUTE                      = 0x05
+    MUTE                        = 0x06
+
+
+# -----------------------------------------------------------------------------
+# Server
+# -----------------------------------------------------------------------------
+class VolumeControlService(gatt.TemplateService):
+    UUID = gatt.GATT_VOLUME_CONTROL_SERVICE
+
+    volume_state: gatt.Characteristic
+    volume_control_point: gatt.Characteristic
+    volume_flags: gatt.Characteristic
+
+    volume_setting: int
+    muted: int
+    change_counter: int
+
+    def __init__(
+        self,
+        step_size: int = 16,
+        volume_setting: int = 0,
+        muted: int = 0,
+        change_counter: int = 0,
+        volume_flags: int = 0,
+    ) -> None:
+        self.step_size = step_size
+        self.volume_setting = volume_setting
+        self.muted = muted
+        self.change_counter = change_counter
+
+        self.volume_state = gatt.Characteristic(
+            uuid=gatt.GATT_VOLUME_STATE_CHARACTERISTIC,
+            properties=(
+                gatt.Characteristic.Properties.READ
+                | gatt.Characteristic.Properties.NOTIFY
+            ),
+            permissions=gatt.Characteristic.Permissions.READ_REQUIRES_ENCRYPTION,
+            value=gatt.CharacteristicValue(read=self._on_read_volume_state),
+        )
+        self.volume_control_point = gatt.Characteristic(
+            uuid=gatt.GATT_VOLUME_CONTROL_POINT_CHARACTERISTIC,
+            properties=gatt.Characteristic.Properties.WRITE,
+            permissions=gatt.Characteristic.Permissions.WRITE_REQUIRES_ENCRYPTION,
+            value=gatt.CharacteristicValue(write=self._on_write_volume_control_point),
+        )
+        self.volume_flags = gatt.Characteristic(
+            uuid=gatt.GATT_VOLUME_FLAGS_CHARACTERISTIC,
+            properties=gatt.Characteristic.Properties.READ,
+            permissions=gatt.Characteristic.Permissions.READ_REQUIRES_ENCRYPTION,
+            value=bytes([volume_flags]),
+        )
+
+        super().__init__(
+            [
+                self.volume_state,
+                self.volume_control_point,
+                self.volume_flags,
+            ]
+        )
+
+    @property
+    def volume_state_bytes(self) -> bytes:
+        return bytes([self.volume_setting, self.muted, self.change_counter])
+
+    @volume_state_bytes.setter
+    def volume_state_bytes(self, new_value: bytes) -> None:
+        self.volume_setting, self.muted, self.change_counter = new_value
+
+    def _on_read_volume_state(self, _connection: Optional[device.Connection]) -> bytes:
+        return self.volume_state_bytes
+
+    def _on_write_volume_control_point(
+        self, connection: Optional[device.Connection], value: bytes
+    ) -> None:
+        assert connection
+
+        opcode = VolumeControlPointOpcode(value[0])
+        change_counter = value[1]
+
+        if change_counter != self.change_counter:
+            raise att.ATT_Error(ErrorCode.INVALID_CHANGE_COUNTER)
+
+        handler = getattr(self, '_on_' + opcode.name.lower())
+        if handler(*value[2:]):
+            self.change_counter = (self.change_counter + 1) % 256
+            connection.abort_on(
+                'disconnection',
+                connection.device.notify_subscribers(
+                    attribute=self.volume_state,
+                    value=self.volume_state_bytes,
+                ),
+            )
+            self.emit(
+                'volume_state', self.volume_setting, self.muted, self.change_counter
+            )
+
+    def _on_relative_volume_down(self) -> bool:
+        old_volume = self.volume_setting
+        self.volume_setting = max(self.volume_setting - self.step_size, MIN_VOLUME)
+        return self.volume_setting != old_volume
+
+    def _on_relative_volume_up(self) -> bool:
+        old_volume = self.volume_setting
+        self.volume_setting = min(self.volume_setting + self.step_size, MAX_VOLUME)
+        return self.volume_setting != old_volume
+
+    def _on_unmute_relative_volume_down(self) -> bool:
+        old_volume, old_muted_state = self.volume_setting, self.muted
+        self.volume_setting = max(self.volume_setting - self.step_size, MIN_VOLUME)
+        self.muted = 0
+        return (self.volume_setting, self.muted) != (old_volume, old_muted_state)
+
+    def _on_unmute_relative_volume_up(self) -> bool:
+        old_volume, old_muted_state = self.volume_setting, self.muted
+        self.volume_setting = min(self.volume_setting + self.step_size, MAX_VOLUME)
+        self.muted = 0
+        return (self.volume_setting, self.muted) != (old_volume, old_muted_state)
+
+    def _on_set_absolute_volume(self, volume_setting: int) -> bool:
+        old_volume_setting = self.volume_setting
+        self.volume_setting = volume_setting
+        return old_volume_setting != self.volume_setting
+
+    def _on_unmute(self) -> bool:
+        old_muted_state = self.muted
+        self.muted = 0
+        return self.muted != old_muted_state
+
+    def _on_mute(self) -> bool:
+        old_muted_state = self.muted
+        self.muted = 1
+        return self.muted != old_muted_state
+
+
+# -----------------------------------------------------------------------------
+# Client
+# -----------------------------------------------------------------------------
+class VolumeControlServiceProxy(gatt_client.ProfileServiceProxy):
+    SERVICE_CLASS = VolumeControlService
+
+    volume_control_point: gatt_client.CharacteristicProxy
+
+    def __init__(self, service_proxy: gatt_client.ServiceProxy) -> None:
+        self.service_proxy = service_proxy
+
+        self.volume_state = gatt.PackedCharacteristicAdapter(
+            service_proxy.get_characteristics_by_uuid(
+                gatt.GATT_VOLUME_STATE_CHARACTERISTIC
+            )[0],
+            'BBB',
+        )
+
+        self.volume_control_point = service_proxy.get_characteristics_by_uuid(
+            gatt.GATT_VOLUME_CONTROL_POINT_CHARACTERISTIC
+        )[0]
+
+        self.volume_flags = gatt.PackedCharacteristicAdapter(
+            service_proxy.get_characteristics_by_uuid(
+                gatt.GATT_VOLUME_FLAGS_CHARACTERISTIC
+            )[0],
+            'B',
+        )