Implement missing _delete() method of filesystem.Channel

kombu/transport/filesystem.py

@@ -262,6 +262,37 @@ def _get(self, queue):
 
         raise Empty()
 
+    def _delete(self, queue, exchange, routing_key, pattern, *args, **kwargs):
+        super()._delete(queue, exchange, routing_key, pattern, *args, **kwargs)
+
+        file = self.control_folder / f"{exchange}.exchange"
+        queue_val = exchange_queue_t(routing_key or "", pattern or "",
+                                     queue or "")
+        f_obj = None
+        try:
+            try:
+                f_obj = file.open("rb+", buffering=0)
+            except FileNotFoundError:
+                # Exchange file was removed concurrently; nothing to update.
+                return
+            lock(f_obj, LOCK_EX)
+            exchange_table = loads(bytes_to_str(f_obj.read()))
+            queues = [exchange_queue_t(*q) for q in exchange_table]
+            original_len = len(queues)
+            try:
+                queues.remove(queue_val)
+            except ValueError:
+                # queue_val was not present; nothing to remove
+                pass
+            if len(queues) != original_len:
+                f_obj.seek(0)
+                f_obj.write(str_to_bytes(dumps(queues)))
+                f_obj.truncate()
+        finally:
+            if f_obj is not None:
+                unlock(f_obj)
+                f_obj.close()
+
     def _purge(self, queue):
         """Remove all messages from `queue`."""
         count = 0