perf: optimize stack fetching (#50)

src/zeal/listeners.py

@@ -123,7 +123,8 @@ def _alert(
         if is_allowlisted:
             return
 
-        final_caller = get_caller()
+        stack = get_stack()
+        final_caller = get_caller(stack)
         if should_include_all_callers:
             message = f"{message} with calls:\n"
             for i, caller in enumerate(calls):
@@ -157,9 +158,10 @@ def notify(
         context = _nplusone_context.get()
         if not context.enabled:
             return
-        caller = get_caller()
+        stack = get_stack()
+        caller = get_caller(stack)
         key = (model, field, f"{caller.filename}:{caller.lineno}")
-        context.calls[key].append(get_stack())
+        context.calls[key].append(stack)
         count = len(context.calls[key])
         if count >= self._threshold and instance_key not in context.ignored:
             message = f"N+1 detected on {model._meta.app_label}.{model.__name__}.{field}"

src/zeal/util.py

@@ -21,12 +21,12 @@ def get_stack() -> list[inspect.FrameInfo]:
     ]
 
 
-def get_caller() -> inspect.FrameInfo:
+def get_caller(stack: list[inspect.FrameInfo]) -> inspect.FrameInfo:
     """
     Returns the filename and line number of the current caller,
     excluding any code in site-packages or zeal.
     """
-    return next(frame for frame in get_stack())
+    return next(frame for frame in stack)
 
 
 def is_single_query(query: Query):