diff options
Diffstat (limited to 'Lib/functools.py')
| -rw-r--r-- | Lib/functools.py | 46 |
1 files changed, 21 insertions, 25 deletions
diff --git a/Lib/functools.py b/Lib/functools.py index 7fc42af..adc7927 100644 --- a/Lib/functools.py +++ b/Lib/functools.py @@ -146,31 +146,35 @@ def lru_cache(maxsize=100, typed=False): # The internals of the lru_cache are encapsulated for thread safety and # to allow the implementation to change (including a possible C version). - def decorating_function(user_function, - *, tuple=tuple, sorted=sorted, map=map, len=len, type=type): + def decorating_function(user_function): cache = dict() hits = misses = 0 - cache_get = cache.get # bound method for fast lookup - kwd_mark = (object(),) # separates positional and keyword args - lock = Lock() # needed because linkedlist isn't threadsafe - root = [] # root of circular doubly linked list + 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 of link fields + 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): + key = args + if kwds: + sorted_items = tuple(sorted(kwds.items())) + key += kwd_mark + sorted_items + if typed: + key += tuple(type(v) for v in args) + if kwds: + key += tuple(type(v) for k, v in sorted_items) + return key if maxsize is None: @wraps(user_function) def wrapper(*args, **kwds): # simple caching without ordering or size limit nonlocal hits, misses - key = args - if kwds: - sorted_items = tuple(sorted(kwds.items())) - key += kwd_mark + sorted_items - if typed: - key += tuple(map(type, args)) - if kwds: - key += tuple(type(v) for k, v in sorted_items) + key = make_key(args, kwds, typed) if kwds or typed else args result = cache_get(key) if result is not None: hits += 1 @@ -184,14 +188,7 @@ def lru_cache(maxsize=100, typed=False): def wrapper(*args, **kwds): # size limited caching that tracks accesses by recency nonlocal hits, misses - key = args - if kwds: - sorted_items = tuple(sorted(kwds.items())) - key += kwd_mark + sorted_items - if typed: - key += tuple(map(type, args)) - if kwds: - key += tuple(type(v) for k, v in sorted_items) + key = make_key(args, kwds, typed) if kwds or typed else args with lock: link = cache_get(key) if link is not None: @@ -210,7 +207,7 @@ def lru_cache(maxsize=100, typed=False): last = root[PREV] link = [last, root, key, result] cache[key] = last[NEXT] = root[PREV] = link - if len(cache) > maxsize: + if _len(cache) > maxsize: # purge least recently used cache entry old_prev, old_next, old_key, old_result = root[NEXT] root[NEXT] = old_next @@ -229,7 +226,6 @@ def lru_cache(maxsize=100, typed=False): nonlocal hits, misses, root with lock: cache.clear() - root = [] root[:] = [root, root, None, None] hits = misses = 0 |