diff options
Diffstat (limited to 'Lib')
| -rw-r--r-- | Lib/functools.py | 25 | ||||
| -rw-r--r-- | Lib/test/test_functools.py | 44 |
2 files changed, 54 insertions, 15 deletions
diff --git a/Lib/functools.py b/Lib/functools.py index c1fa170..c223a62 100644 --- a/Lib/functools.py +++ b/Lib/functools.py @@ -12,7 +12,7 @@ __all__ = ['update_wrapper', 'wraps', 'WRAPPER_ASSIGNMENTS', 'WRAPPER_UPDATES', 'total_ordering', 'cmp_to_key', 'lru_cache', 'reduce', 'partial'] from _functools import partial, reduce -from collections import OrderedDict +from collections import OrderedDict, namedtuple try: from _thread import allocate_lock as Lock except: @@ -114,12 +114,15 @@ def cmp_to_key(mycmp): raise TypeError('hash not implemented') return K +_CacheInfo = namedtuple("CacheInfo", "maxsize, size, hits, misses") + def lru_cache(maxsize=100): """Least-recently-used cache decorator. Arguments to the cached function must be hashable. - Performance statistics stored in f.cache_hits and f.cache_misses. + Significant statistics (maxsize, size, hits, misses) are + available through the f.cache_info() named tuple. Clear the cache and statistics using f.cache_clear(). The underlying function is stored in f.__wrapped__. @@ -127,7 +130,7 @@ def lru_cache(maxsize=100): """ # Users should only access the lru_cache through its public API: - # cache_hits, cache_misses, cache_clear(), and __wrapped__ + # cache_info, cache_clear, and f.__wrapped__ # The internals of the lru_cache are encapsulated for thread safety and # to allow the implementation to change (including a possible C version). @@ -137,11 +140,13 @@ def lru_cache(maxsize=100): cache = OrderedDict() # ordered least recent to most recent cache_popitem = cache.popitem cache_renew = cache.move_to_end + hits = misses = 0 kwd_mark = object() # separate positional and keyword args lock = Lock() @wraps(user_function) def wrapper(*args, **kwds): + nonlocal hits, misses key = args if kwds: key += (kwd_mark,) + tuple(sorted(kwds.items())) @@ -149,23 +154,29 @@ def lru_cache(maxsize=100): with lock: result = cache[key] cache_renew(key) # record recent use of this key - wrapper.cache_hits += 1 + hits += 1 except KeyError: result = user_function(*args, **kwds) with lock: cache[key] = result # record recent use of this key - wrapper.cache_misses += 1 + misses += 1 if len(cache) > maxsize: cache_popitem(0) # purge least recently used cache entry return result + def cache_info(): + """Report significant cache statistics""" + with lock: + return _CacheInfo(maxsize, len(cache), hits, misses) + def cache_clear(): """Clear the cache and cache statistics""" + nonlocal hits, misses with lock: cache.clear() - wrapper.cache_hits = wrapper.cache_misses = 0 + hits = misses = 0 - wrapper.cache_hits = wrapper.cache_misses = 0 + wrapper.cache_info = cache_info wrapper.cache_clear = cache_clear return wrapper diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py index 65ef9b4..c877f88 100644 --- a/Lib/test/test_functools.py +++ b/Lib/test/test_functools.py @@ -501,6 +501,11 @@ class TestLRU(unittest.TestCase): def orig(x, y): return 3*x+y f = functools.lru_cache(maxsize=20)(orig) + maxsize, currsize, hits, misses = f.cache_info() + self.assertEqual(maxsize, 20) + self.assertEqual(currsize, 0) + self.assertEqual(hits, 0) + self.assertEqual(misses, 0) domain = range(5) for i in range(1000): @@ -508,21 +513,29 @@ class TestLRU(unittest.TestCase): actual = f(x, y) expected = orig(x, y) self.assertEqual(actual, expected) - self.assertTrue(f.cache_hits > f.cache_misses) - self.assertEqual(f.cache_hits + f.cache_misses, 1000) + maxsize, currsize, hits, misses = f.cache_info() + self.assertTrue(hits > misses) + self.assertEqual(hits + misses, 1000) + self.assertEqual(currsize, 20) f.cache_clear() # test clearing - self.assertEqual(f.cache_hits, 0) - self.assertEqual(f.cache_misses, 0) + maxsize, currsize, hits, misses = f.cache_info() + self.assertEqual(hits, 0) + self.assertEqual(misses, 0) + self.assertEqual(currsize, 0) f(x, y) - self.assertEqual(f.cache_hits, 0) - self.assertEqual(f.cache_misses, 1) + maxsize, currsize, hits, misses = f.cache_info() + self.assertEqual(hits, 0) + self.assertEqual(misses, 1) + self.assertEqual(currsize, 1) # Test bypassing the cache self.assertIs(f.__wrapped__, orig) f.__wrapped__(x, y) - self.assertEqual(f.cache_hits, 0) - self.assertEqual(f.cache_misses, 1) + maxsize, currsize, hits, misses = f.cache_info() + self.assertEqual(hits, 0) + self.assertEqual(misses, 1) + self.assertEqual(currsize, 1) # test size zero (which means "never-cache") @functools.lru_cache(0) @@ -530,10 +543,15 @@ class TestLRU(unittest.TestCase): nonlocal f_cnt f_cnt += 1 return 20 + self.assertEqual(f.cache_info().maxsize, 0) f_cnt = 0 for i in range(5): self.assertEqual(f(), 20) self.assertEqual(f_cnt, 5) + maxsize, currsize, hits, misses = f.cache_info() + self.assertEqual(hits, 0) + self.assertEqual(misses, 5) + self.assertEqual(currsize, 0) # test size one @functools.lru_cache(1) @@ -541,10 +559,15 @@ class TestLRU(unittest.TestCase): nonlocal f_cnt f_cnt += 1 return 20 + self.assertEqual(f.cache_info().maxsize, 1) f_cnt = 0 for i in range(5): self.assertEqual(f(), 20) self.assertEqual(f_cnt, 1) + maxsize, currsize, hits, misses = f.cache_info() + self.assertEqual(hits, 4) + self.assertEqual(misses, 1) + self.assertEqual(currsize, 1) # test size two @functools.lru_cache(2) @@ -552,11 +575,16 @@ class TestLRU(unittest.TestCase): nonlocal f_cnt f_cnt += 1 return x*10 + self.assertEqual(f.cache_info().maxsize, 2) f_cnt = 0 for x in 7, 9, 7, 9, 7, 9, 8, 8, 8, 9, 9, 9, 8, 8, 8, 7: # * * * * self.assertEqual(f(x), x*10) self.assertEqual(f_cnt, 4) + maxsize, currsize, hits, misses = f.cache_info() + self.assertEqual(hits, 12) + self.assertEqual(misses, 4) + self.assertEqual(currsize, 2) def test_main(verbose=None): test_classes = ( |