ble: simplify GATT characteristic lookup

No need to get triggered by BlueZDeviceManager when it finds any GATT
characteristic. The BlueZDevice just needs its 'ServicesResolved' and
can resolve the GATT characteristics itself.

This solves a FIXME.

Signed-off-by: Daniel Martin <consume.noise@gmail.com>

tuhi/ble.py

@@ -81,9 +81,7 @@ class BlueZDevice(GObject.Object):
     Abstraction for a org.bluez.Device1 object
 
     The device initializes itself based on the given object manager and
-    object, specifically: it resolves its services and gatt characteristics.
-    The device resolves itself where possible, if one of its
-    services/characteristics comes in late, call resolve().
+    object, specifically: it resolves its gatt characteristics.
 
     To connect to the real device, call connect_to_device(). The 'connected'
     and 'disconnected' signals are emitted when the connection is
@@ -108,13 +106,14 @@ class BlueZDevice(GObject.Object):
         GObject.Object.__init__(self)
         self.objpath = obj.get_object_path()
         self.obj = obj
+        self.om = om
         self.interface = obj.get_interface(ORG_BLUEZ_DEVICE1)
         assert(self.interface is not None)
 
         logger.debug(f'Device {self.objpath} - {self.address} - {self.name}')
 
         self.characteristics = {}
-        self.resolve(om)
+        self._resolve_gatt_characteristics()
         self.interface.connect('g-properties-changed', self._on_properties_changed)
         if self.connected:
             self.emit('connected')
@@ -167,48 +166,21 @@ class BlueZDevice(GObject.Object):
 
         return None
 
-    def resolve(self, om):
+    def _resolve_gatt_characteristics(self):
         '''
-        Resolve the GattServices and GattCharacteristics. This function does
-        not need to be called for existing objects but if a device comes in
-        at runtime not all services may have been resolved by the time the
-        org.bluez.Device1 shows up.
+        Resolve the GattCharacteristics.
         '''
-        objects = om.get_objects()
-        self._resolve_gatt_services(objects)
-
-    def _resolve_gatt_services(self, objects):
-        self.gatt_services = []
-        for obj in objects:
-            i = obj.get_interface(ORG_BLUEZ_GATTSERVICE1)
-            if i is None:
-                continue
-
-            device = i.get_cached_property('Device').get_string()
-            if device != self.objpath:
-                continue
-
-            logger.debug(f'GattService1: {obj.get_object_path()} for device {device}')
-            self.gatt_services.append(obj)
-            self._resolve_gatt_characteristics(obj, objects)
-
-    def _resolve_gatt_characteristics(self, service_obj, objects):
-        for obj in objects:
+        objs = self.om.get_objects(interface=ORG_BLUEZ_GATTCHARACTERISTIC1,
+                                   base_path=self.objpath)
+        for obj in objs:
             i = obj.get_interface(ORG_BLUEZ_GATTCHARACTERISTIC1)
-            if i is None:
+            uuid = i.get_cached_property('UUID').unpack()
+
+            if uuid in self.characteristics:
                 continue
 
-            service = i.get_cached_property('Service').get_string()
-            if service != service_obj.get_object_path():
-                continue
-
-            chrc = BlueZCharacteristic(obj)
-            if chrc.uuid in self.characteristics:
-                continue
-
-            logger.debug(f'GattCharacteristic: {chrc.uuid} for service {service}')
-
-            self.characteristics[chrc.uuid] = chrc
+            self.characteristics[uuid] = BlueZCharacteristic(obj)
+            logger.debug(f'GattCharacteristic: {uuid}')
 
     def connect_device(self):
         '''
@@ -263,6 +235,7 @@ class BlueZDevice(GObject.Object):
                 self.emit('disconnected')
         if 'ServicesResolved' in properties:
             if properties['ServicesResolved']:
+                self._resolve_gatt_characteristics()
                 self.emit('connected')
         if 'RSSI' in properties:
             self.emit('updated')
@@ -442,14 +415,7 @@ class BlueZDeviceManager(GObject.Object):
         '''Callback for ObjectManager's object-added'''
         objpath = obj.get_object_path()
         logger.debug(f'Object added: {objpath}')
-        needs_resolve = self._process_object(obj, event=True)
-
-        # we had at least one characteristic added, need to resolve the
-        # devices.
-        # FIXME: this isn't the most efficient way...
-        if needs_resolve:
-            for d in self.devices:
-                d.resolve(om)
+        self._process_object(obj, event=True)
 
     def _on_om_object_removed(self, om, obj):
         '''Callback for ObjectManager's object-removed'''
@@ -464,9 +430,7 @@ class BlueZDeviceManager(GObject.Object):
         elif obj.get_interface(ORG_BLUEZ_DEVICE1) is not None:
             self._process_device(obj)
         elif obj.get_interface(ORG_BLUEZ_GATTCHARACTERISTIC1) is not None:
-            return True
-
-        return False
+            self._process_characteristic(obj)
 
     def _process_adapter(self, obj):
         objpath = obj.get_object_path()