[Python-checkins] cpython: Track the cache size directly.
raymond.hettinger
python-checkins at python.org
Mon Apr 30 03:09:21 CEST 2012
http://hg.python.org/cpython/rev/d4fd58fff480
changeset: 76656:d4fd58fff480
user: Raymond Hettinger <python at rcn.com>
date: Sun Apr 29 18:09:02 2012 -0700
summary:
Track the cache size directly.
files:
Lib/functools.py | 21 +++++++++++----------
1 files changed, 11 insertions(+), 10 deletions(-)
diff --git a/Lib/functools.py b/Lib/functools.py
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -168,15 +168,14 @@
# to allow the implementation to change (including a possible C version).
# Constants shared by all lru cache instances:
- kwd_mark = (object(),) # separate positional and keyword args
- sentinel = object() # unique object used to signal cache misses
- _len = len # localize the global len() function
+ kwd_mark = (object(),) # separate positional and keyword args
+ sentinel = object() # unique object used to signal cache misses
PREV, NEXT, KEY, RESULT = 0, 1, 2, 3 # names for the link fields
def decorating_function(user_function):
cache = {}
- hits = misses = 0
+ hits = misses = currsize = 0
cache_get = cache.get # bound method to lookup a key or return None
lock = Lock() # because linkedlist updates aren't threadsafe
root = [] # root of the circular doubly linked list
@@ -209,7 +208,7 @@
def wrapper(*args, **kwds):
# simple caching without ordering or size limit
- nonlocal hits, misses
+ nonlocal hits, misses, currsize
key = make_key(args, kwds, typed) if kwds or typed else args
result = cache_get(key, sentinel)
if result is not sentinel:
@@ -218,13 +217,14 @@
result = user_function(*args, **kwds)
cache[key] = result
misses += 1
+ currsize += 1
return result
else:
def wrapper(*args, **kwds):
# size limited caching that tracks accesses by recency
- nonlocal root, hits, misses
+ nonlocal root, hits, misses, currsize
key = make_key(args, kwds, typed) if kwds or typed else args
with lock:
link = cache_get(key)
@@ -241,11 +241,12 @@
return result
result = user_function(*args, **kwds)
with lock:
- if _len(cache) < maxsize:
+ if currsize < maxsize:
# put result in a new link at the front of the queue
last = root[PREV]
link = [last, root, key, result]
cache[key] = last[NEXT] = root[PREV] = link
+ currsize += 1
else:
# use root to store the new key and result
root[KEY] = key
@@ -261,15 +262,15 @@
def cache_info():
"""Report cache statistics"""
with lock:
- return _CacheInfo(hits, misses, maxsize, len(cache))
+ return _CacheInfo(hits, misses, maxsize, currsize)
def cache_clear():
"""Clear the cache and cache statistics"""
- nonlocal hits, misses
+ nonlocal hits, misses, currsize
with lock:
cache.clear()
root[:] = [root, root, None, None]
- hits = misses = 0
+ hits = misses = currsize = 0
wrapper.cache_info = cache_info
wrapper.cache_clear = cache_clear
--
Repository URL: http://hg.python.org/cpython
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