Replace NSRunLoop with dispatch queue

This replaces the NSRunLoop integration in the corebluetooth backend
with a dispatch queue. This causes callbacks to be dispatched on a
background thread instead of on the main dispatch queue on the main
thread. `call_soon_threadsafe()` is used to synchronize the events
with the event loop where the central manager was created.

The NSRunLoop caused problems because it had to manually be called from
the main thread. This left an asyncio task that had to be manually
stopped at the end of a program to prevent errors about the still
running task (issue: hbldh#111). The NSRunLoop implementation was
also not very efficient since it was waking up the event loop every
millisecond to check for events.

bleak/backends/corebluetooth/CentralManagerDelegate.py

@@ -30,6 +30,7 @@
     NSNumber,
     NSError,
 )
+from libdispatch import dispatch_queue_create, DISPATCH_QUEUE_SERIAL
 
 from bleak.backends.corebluetooth.PeripheralDelegate import PeripheralDelegate
 from bleak.backends.corebluetooth.device import BLEDeviceCoreBluetooth
@@ -58,10 +59,7 @@ def init(self):
         if self is None:
             return None
 
-        self.central_manager = CBCentralManager.alloc().initWithDelegate_queue_(
-            self, None
-        )
-
+        self.event_loop = asyncio.get_event_loop()
         self.connected_peripheral_delegate = None
         self.connected_peripheral = None
         self._connection_state = CMDConnectionState.DISCONNECTED
@@ -75,6 +73,10 @@ def init(self):
         if not self.compliant():
             logger.warning("CentralManagerDelegate is not compliant")
 
+        self.central_manager = CBCentralManager.alloc().initWithDelegate_queue_(
+            self, dispatch_queue_create(b"bleak.corebluetooth", DISPATCH_QUEUE_SERIAL)
+        )
+
         return self
 
     # User defined functions
@@ -151,7 +153,8 @@ async def disconnect(self) -> bool:
 
     # Protocol Functions
 
-    def centralManagerDidUpdateState_(self, centralManager):
+    @objc.python_method
+    def did_update_state(self, centralManager):
         if centralManager.state() == CBManagerStateUnknown:
             logger.debug("Cannot detect bluetooth device")
         elif centralManager.state() == CBManagerStateResetting:
@@ -170,7 +173,15 @@ def centralManagerDidUpdateState_(self, centralManager):
         else:
             self.powered_on_event.clear()
 
-    def centralManager_didDiscoverPeripheral_advertisementData_RSSI_(
+    def centralManagerDidUpdateState_(self, centralManager):
+        logger.debug("centralManagerDidUpdateState_")
+        self.event_loop.call_soon_threadsafe(
+            self.did_update_state,
+            centralManager,
+        )
+
+    @objc.python_method
+    def did_discover_peripheral(
         self,
         central: CBCentralManager,
         peripheral: CBPeripheral,
@@ -210,7 +221,24 @@ def centralManager_didDiscoverPeripheral_advertisementData_RSSI_(
         logger.debug("Discovered device {}: {} @ RSSI: {} (kCBAdvData {})".format(
                 uuid_string, device.name, RSSI, advertisementData.keys()))
 
-    def centralManager_didConnectPeripheral_(self, central, peripheral):
+    def centralManager_didDiscoverPeripheral_advertisementData_RSSI_(
+        self,
+        central: CBCentralManager,
+        peripheral: CBPeripheral,
+        advertisementData: NSDictionary,
+        RSSI: NSNumber,
+    ):
+        logger.debug("centralManager_didDiscoverPeripheral_advertisementData_RSSI_")
+        self.event_loop.call_soon_threadsafe(
+            self.did_discover_peripheral,
+            central,
+            peripheral,
+            advertisementData,
+            RSSI,
+        )
+
+    @objc.python_method
+    def did_connect_peripheral(self, central, peripheral):
         logger.debug(
             "Successfully connected to device uuid {}".format(
                 peripheral.identifier().UUIDString()
@@ -220,7 +248,16 @@ def centralManager_didConnectPeripheral_(self, central, peripheral):
         self.connected_peripheral_delegate = peripheralDelegate
         self._connection_state = CMDConnectionState.CONNECTED
 
-    def centralManager_didFailToConnectPeripheral_error_(
+    def centralManager_didConnectPeripheral_(self, central, peripheral):
+        logger.debug("centralManager_didConnectPeripheral_")
+        self.event_loop.call_soon_threadsafe(
+            self.did_connect_peripheral,
+            central,
+            peripheral,
+        )
+
+    @objc.python_method
+    def did_fail_to_connect_peripheral(
         self, centralManager: CBCentralManager, peripheral: CBPeripheral, error: NSError
     ):
         logger.debug(
@@ -230,7 +267,19 @@ def centralManager_didFailToConnectPeripheral_error_(
         )
         self._connection_state = CMDConnectionState.DISCONNECTED
 
-    def centralManager_didDisconnectPeripheral_error_(
+    def centralManager_didFailToConnectPeripheral_error_(
+        self, centralManager: CBCentralManager, peripheral: CBPeripheral, error: NSError
+    ):
+        logger.debug("centralManager_didFailToConnectPeripheral_error_")
+        self.event_loop.call_soon_threadsafe(
+            self.did_fail_to_connect_peripheral,
+            centralManager,
+            peripheral,
+            error,
+        )
+
+    @objc.python_method
+    def did_disconnect_peripheral(
         self, central: CBCentralManager, peripheral: CBPeripheral, error: NSError
     ):
         logger.debug("Peripheral Device disconnected!")
@@ -239,8 +288,18 @@ def centralManager_didDisconnectPeripheral_error_(
         if self.disconnected_callback is not None:
             self.disconnected_callback()
 
+    def centralManager_didDisconnectPeripheral_error_(
+        self, central: CBCentralManager, peripheral: CBPeripheral, error: NSError
+    ):
+        logger.debug("centralManager_didDisconnectPeripheral_error_")
+        self.event_loop.call_soon_threadsafe(
+            self.did_disconnect_peripheral,
+            central,
+            peripheral,
+            error,
+        )
+
 
 def string2uuid(uuid_str: str) -> CBUUID:
     """Convert a string to a uuid"""
     return CBUUID.UUIDWithString_(uuid_str)
-

bleak/backends/corebluetooth/PeripheralDelegate.py

@@ -58,6 +58,7 @@ def initWithPeripheral_(self, peripheral: CBPeripheral):
         self.peripheral = peripheral
         self.peripheral.setDelegate_(self)
 
+        self._event_loop = asyncio.get_event_loop()
         self._services_discovered_event = asyncio.Event()
 
         self._service_characteristic_discovered_events = _EventDict()
@@ -211,7 +212,9 @@ async def stopNotify_(self, characteristic: CBCharacteristic) -> bool:
         return True
 
     # Protocol Functions
-    def peripheral_didDiscoverServices_(
+
+    @objc.python_method
+    def did_discover_services(
         self, peripheral: CBPeripheral, error: NSError
     ) -> None:
         if error is not None:
@@ -220,7 +223,18 @@ def peripheral_didDiscoverServices_(
         logger.debug("Services discovered")
         self._services_discovered_event.set()
 
-    def peripheral_didDiscoverCharacteristicsForService_error_(
+    def peripheral_didDiscoverServices_(
+        self, peripheral: CBPeripheral, error: NSError
+    ) -> None:
+        logger.debug("peripheral_didDiscoverServices_")
+        self._event_loop.call_soon_threadsafe(
+            self.did_discover_services,
+            peripheral,
+            error,
+        )
+
+    @objc.python_method
+    def did_discover_characteristics_for_service(
         self, peripheral: CBPeripheral, service: CBService, error: NSError
     ):
         sUUID = service.UUID().UUIDString()
@@ -236,7 +250,19 @@ def peripheral_didDiscoverCharacteristicsForService_error_(
         else:
             logger.debug("Unexpected event didDiscoverCharacteristicsForService")
 
-    def peripheral_didDiscoverDescriptorsForCharacteristic_error_(
+    def peripheral_didDiscoverCharacteristicsForService_error_(
+        self, peripheral: CBPeripheral, service: CBService, error: NSError
+    ):
+        logger.debug("peripheral_didDiscoverCharacteristicsForService_error_")
+        self._event_loop.call_soon_threadsafe(
+            self.did_discover_characteristics_for_service,
+            peripheral,
+            service,
+            error,
+        )
+
+    @objc.python_method
+    def did_discover_descriptors_for_characteristic(
         self, peripheral: CBPeripheral, characteristic: CBCharacteristic, error: NSError
     ):
         cUUID = characteristic.UUID().UUIDString()
@@ -254,7 +280,19 @@ def peripheral_didDiscoverDescriptorsForCharacteristic_error_(
         else:
             logger.warning("Unexpected event didDiscoverDescriptorsForCharacteristic")
 
-    def peripheral_didUpdateValueForCharacteristic_error_(
+    def peripheral_didDiscoverDescriptorsForCharacteristic_error_(
+        self, peripheral: CBPeripheral, characteristic: CBCharacteristic, error: NSError
+    ):
+        logger.debug("peripheral_didDiscoverDescriptorsForCharacteristic_error_")
+        self._event_loop.call_soon_threadsafe(
+            self.did_discover_descriptors_for_characteristic,
+            peripheral,
+            characteristic,
+            error,
+        )
+
+    @objc.python_method
+    def did_update_value_for_characteristic(
         self, peripheral: CBPeripheral, characteristic: CBCharacteristic, error: NSError
     ):
         cUUID = characteristic.UUID().UUIDString()
@@ -275,7 +313,19 @@ def peripheral_didUpdateValueForCharacteristic_error_(
             # only expected on read
             pass
 
-    def peripheral_didUpdateValueForDescriptor_error_(
+    def peripheral_didUpdateValueForCharacteristic_error_(
+        self, peripheral: CBPeripheral, characteristic: CBCharacteristic, error: NSError
+    ):
+        logger.debug("peripheral_didUpdateValueForCharacteristic_error_")
+        self._event_loop.call_soon_threadsafe(
+            self.did_update_value_for_characteristic,
+            peripheral,
+            characteristic,
+            error,
+        )
+
+    @objc.python_method
+    def did_update_value_for_descriptor(
         self, peripheral: CBPeripheral, descriptor: CBDescriptor, error: NSError
     ):
         dUUID = descriptor.UUID().UUIDString()
@@ -291,7 +341,19 @@ def peripheral_didUpdateValueForDescriptor_error_(
         else:
             logger.warning("Unexpected event didUpdateValueForDescriptor")
 
-    def peripheral_didWriteValueForCharacteristic_error_(
+    def peripheral_didUpdateValueForDescriptor_error_(
+        self, peripheral: CBPeripheral, descriptor: CBDescriptor, error: NSError
+    ):
+        logger.debug("peripheral_didUpdateValueForDescriptor_error_")
+        self._event_loop.call_soon_threadsafe(
+            self.did_update_value_for_descriptor,
+            peripheral,
+            descriptor,
+            error,
+        )
+
+    @objc.python_method
+    def did_write_value_for_characteristic(
         self, peripheral: CBPeripheral, characteristic: CBCharacteristic, error: NSError
     ):
         cUUID = characteristic.UUID().UUIDString()
@@ -308,7 +370,19 @@ def peripheral_didWriteValueForCharacteristic_error_(
             # event only expected on write with response
             pass
 
-    def peripheral_didWriteValueForDescriptor_error_(
+    def peripheral_didWriteValueForCharacteristic_error_(
+        self, peripheral: CBPeripheral, characteristic: CBCharacteristic, error: NSError
+    ):
+        logger.debug("peripheral_didWriteValueForCharacteristic_error_")
+        self._event_loop.call_soon_threadsafe(
+            self.did_write_value_for_characteristic,
+            peripheral,
+            characteristic,
+            error,
+        )
+
+    @objc.python_method
+    def did_write_value_for_descriptor(
         self, peripheral: CBPeripheral, descriptor: CBDescriptor, error: NSError
     ):
         dUUID = descriptor.UUID().UUIDString()
@@ -322,7 +396,19 @@ def peripheral_didWriteValueForDescriptor_error_(
         else:
             logger.warning("Unexpected event didWriteValueForDescriptor")
 
-    def peripheral_didUpdateNotificationStateForCharacteristic_error_(
+    def peripheral_didWriteValueForDescriptor_error_(
+        self, peripheral: CBPeripheral, descriptor: CBDescriptor, error: NSError
+    ):
+        logger.debug("peripheral_didWriteValueForDescriptor_error_")
+        self._event_loop.call_soon_threadsafe(
+            self.did_write_value_for_descriptor,
+            peripheral,
+            descriptor,
+            error,
+        )
+
+    @objc.python_method
+    def did_update_notification_for_characteristic(
         self, peripheral: CBPeripheral, characteristic: CBCharacteristic, error: NSError
     ):
         cUUID = characteristic.UUID().UUIDString()
@@ -342,3 +428,13 @@ def peripheral_didUpdateNotificationStateForCharacteristic_error_(
                 "Unexpected event didUpdateNotificationStateForCharacteristic"
             )
 
+    def peripheral_didUpdateNotificationStateForCharacteristic_error_(
+        self, peripheral: CBPeripheral, characteristic: CBCharacteristic, error: NSError
+    ):
+        logger.debug("peripheral_didUpdateNotificationStateForCharacteristic_error_")
+        self._event_loop.call_soon_threadsafe(
+            self.did_update_notification_for_characteristic,
+            peripheral,
+            characteristic,
+            error,
+        )

bleak/backends/corebluetooth/__init__.py

@@ -7,7 +7,6 @@
 """
 
 import asyncio
-from Foundation import NSDate, NSDefaultRunLoopMode, NSRunLoop
 from .CentralManagerDelegate import CentralManagerDelegate
 import objc
 
@@ -19,29 +18,9 @@ class Application:
     This is a temporary application class responsible for running the NSRunLoop
     so that events within CoreBluetooth are appropriately handled
     """
-
-    ns_run_loop_done = False
-    ns_run_loop_interval = 0.001
-
     def __init__(self):
-        self.main_loop = asyncio.get_event_loop()
-        self.main_loop.create_task(self._handle_nsrunloop())
-
-        self.nsrunloop = NSRunLoop.currentRunLoop()
-
         self.central_manager_delegate = CentralManagerDelegate.alloc().init()
 
-    def __del__(self):
-        self.ns_run_loop_done = True
-
-    async def _handle_nsrunloop(self):
-        while not self.ns_run_loop_done:
-            time_interval = NSDate.alloc().initWithTimeIntervalSinceNow_(
-                self.ns_run_loop_interval
-            )
-            self.nsrunloop.runMode_beforeDate_(NSDefaultRunLoopMode, time_interval)
-            await asyncio.sleep(0)
-
 
 # Restructure this later: Global isn't the prettiest way of doing this...
 global CBAPP