Low overhead path for maxsize==0
diff --git a/Lib/functools.py b/Lib/functools.py
index f4c8271..de30a92 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -170,15 +170,16 @@
cache = dict()
hits = misses = 0
+ kwd_mark = (object(),) # separate positional and keyword args
cache_get = cache.get # bound method to lookup key or return None
_len = len # localize the global len() function
- kwd_mark = (object(),) # separate positional and keyword args
lock = Lock() # because linkedlist updates aren't threadsafe
root = [] # root of the circular doubly linked list
root[:] = [root, root, None, None] # initialize by pointing to self
PREV, NEXT, KEY, RESULT = 0, 1, 2, 3 # names for the link fields
def make_key(args, kwds, typed, tuple=tuple, sorted=sorted, type=type):
+ # helper function to build a cache key from positional and keyword args
key = args
if kwds:
sorted_items = tuple(sorted(kwds.items()))
@@ -189,7 +190,17 @@
key += tuple(type(v) for k, v in sorted_items)
return key
- if maxsize is None:
+ if maxsize == 0:
+
+ @wraps(user_function)
+ def wrapper(*args, **kwds):
+ # no caching, just do a statistics update after a successful call
+ nonlocal misses
+ result = user_function(*args, **kwds)
+ misses += 1
+ return result
+
+ elif maxsize is None:
@wraps(user_function)
def wrapper(*args, **kwds):