No need to create and destroy links when updating a fixed-sized circular queue.
diff --git a/Lib/functools.py b/Lib/functools.py
index 299e9d8..5cf8f1c 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -219,7 +219,7 @@
def wrapper(*args, **kwds):
# size limited caching that tracks accesses by recency
- nonlocal hits, misses
+ nonlocal root, hits, misses
key = make_key(args, kwds, typed) if kwds or typed else args
with lock:
link = cache_get(key)
@@ -236,16 +236,21 @@
return result
result = user_function(*args, **kwds)
with lock:
- # put result in a new link at the front of the list
- last = root[PREV]
- link = [last, root, key, result]
- cache[key] = last[NEXT] = root[PREV] = link
- if _len(cache) > maxsize:
- # purge the least recently used cache entry
- old_prev, old_next, old_key, old_result = root[NEXT]
- root[NEXT] = old_next
- old_next[PREV] = root
- del cache[old_key]
+ if _len(cache) < maxsize:
+ # put result in a new link at the front of the list
+ last = root[PREV]
+ link = [last, root, key, result]
+ cache[key] = last[NEXT] = root[PREV] = link
+ else:
+ # use root to store the new key and result
+ root[KEY] = key
+ root[RESULT] = result
+ cache[key] = root
+ # empty the oldest link and make it the new root
+ root = root[NEXT]
+ del cache[root[KEY]]
+ root[KEY] = None
+ root[RESULT] = None
misses += 1
return result