improve vendor event support

bumble/hci.py

@@ -4996,6 +4996,7 @@ class HCI_Event(HCI_Packet):
     hci_packet_type = HCI_EVENT_PACKET
     event_names: Dict[int, str] = {}
     event_classes: Dict[int, Type[HCI_Event]] = {}
+    vendor_factory: Optional[Callable[[bytes], Optional[HCI_Event]]] = None
 
     @staticmethod
     def event(fields=()):
@@ -5053,31 +5054,41 @@ class HCI_Event(HCI_Packet):
 
         return event_class
 
-    @staticmethod
-    def from_bytes(packet: bytes) -> HCI_Event:
+    @classmethod
+    def from_bytes(cls, packet: bytes) -> HCI_Event:
         event_code = packet[1]
         length = packet[2]
         parameters = packet[3:]
         if len(parameters) != length:
             raise InvalidPacketError('invalid packet length')
 
-        cls: Any
+        subclass: Any
         if event_code == HCI_LE_META_EVENT:
             # We do this dispatch here and not in the subclass in order to avoid call
             # loops
             subevent_code = parameters[0]
-            cls = HCI_LE_Meta_Event.subevent_classes.get(subevent_code)
-            if cls is None:
+            subclass = HCI_LE_Meta_Event.subevent_classes.get(subevent_code)
+            if subclass is None:
                 # No class registered, just use a generic class instance
                 return HCI_LE_Meta_Event(subevent_code, parameters)
+        elif event_code == HCI_VENDOR_EVENT:
+            # Invoke all the registered factories to see if any of them can handle
+            # the event
+            if cls.vendor_factory:
+                if event := cls.vendor_factory(parameters):
+                    return event
+
+            # No factory, or the factory could not create an instance,
+            # return a generic vendor event
+            return HCI_Event(event_code, parameters)
         else:
-            cls = HCI_Event.event_classes.get(event_code)
-            if cls is None:
+            subclass = HCI_Event.event_classes.get(event_code)
+            if subclass is None:
                 # No class registered, just use a generic class instance
                 return HCI_Event(event_code, parameters)
 
         # Invoke the factory to create a new instance
-        return cls.from_parameters(parameters)  # type: ignore
+        return subclass.from_parameters(parameters)  # type: ignore
 
     @classmethod
     def from_parameters(cls, parameters):
@@ -5127,7 +5138,7 @@ class HCI_Extended_Event(HCI_Event):
     '''
 
     subevent_names: Dict[int, str] = {}
-    subevent_classes: Dict[int, Type[HCI_Extended_Event]]
+    subevent_classes: Dict[int, Type[HCI_Extended_Event]] = {}
 
     @classmethod
     def event(cls, fields=()):
@@ -5178,7 +5189,22 @@ class HCI_Extended_Event(HCI_Event):
         cls.subevent_names.update(cls.subevent_map(symbols))
 
     @classmethod
-    def from_parameters(cls, parameters):
+    def subclass_from_parameters(
+        cls, parameters: bytes
+    ) -> Optional[HCI_Extended_Event]:
+        """
+        Factory method that parses the subevent code, finds a registered subclass,
+        and creates an instance if found.
+        """
+        subevent_code = parameters[0]
+        if subclass := cls.subevent_classes.get(subevent_code):
+            return subclass.from_parameters(parameters)
+
+        return None
+
+    @classmethod
+    def from_parameters(cls, parameters: bytes) -> HCI_Extended_Event:
+        """Factory method for subclasses (the subevent code has already been parsed)"""
         self = cls.__new__(cls)
         HCI_Extended_Event.__init__(self, self.subevent_code, parameters)
         if fields := getattr(self, 'fields', None):
@@ -6092,8 +6118,9 @@ class HCI_Command_Complete_Event(HCI_Event):
     See Bluetooth spec @ 7.7.14 Command Complete Event
     '''
 
-    return_parameters = b''
+    num_hci_command_packets: int
     command_opcode: int
+    return_parameters = b''
 
     def map_return_parameters(self, return_parameters):
         '''Map simple 'status' return parameters to their named constant form'''