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Refactor "cached" decorator and move implementation details to privat…
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…e submodule.
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Thomas Kemmer committed Feb 20, 2025
1 parent b072920 commit 53120ae
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Showing 2 changed files with 159 additions and 127 deletions.
133 changes: 6 additions & 127 deletions src/cachetools/__init__.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@
import time

from . import keys
from ._decorators import _cached_wrapper


class _DefaultSize:
Expand Down Expand Up @@ -643,150 +644,28 @@ def cached(cache, key=keys.hashkey, lock=None, info=False):

def decorator(func):
if info:
hits = misses = 0

if isinstance(cache, Cache):

def getinfo():
nonlocal hits, misses
def make_info(hits, misses):
return _CacheInfo(hits, misses, cache.maxsize, cache.currsize)

elif isinstance(cache, collections.abc.Mapping):

def getinfo():
nonlocal hits, misses
def make_info(hits, misses):
return _CacheInfo(hits, misses, None, len(cache))

else:

def getinfo():
nonlocal hits, misses
def make_info(hits, misses):
return _CacheInfo(hits, misses, 0, 0)

if cache is None:

def wrapper(*args, **kwargs):
nonlocal misses
misses += 1
return func(*args, **kwargs)

def cache_clear():
nonlocal hits, misses
hits = misses = 0

cache_info = getinfo

elif lock is None:

def wrapper(*args, **kwargs):
nonlocal hits, misses
k = key(*args, **kwargs)
try:
result = cache[k]
hits += 1
return result
except KeyError:
misses += 1
v = func(*args, **kwargs)
try:
cache[k] = v
except ValueError:
pass # value too large
return v

def cache_clear():
nonlocal hits, misses
cache.clear()
hits = misses = 0

cache_info = getinfo

else:

def wrapper(*args, **kwargs):
nonlocal hits, misses
k = key(*args, **kwargs)
try:
with lock:
result = cache[k]
hits += 1
return result
except KeyError:
with lock:
misses += 1
v = func(*args, **kwargs)
# in case of a race, prefer the item already in the cache
try:
with lock:
return cache.setdefault(k, v)
except ValueError:
return v # value too large

def cache_clear():
nonlocal hits, misses
with lock:
cache.clear()
hits = misses = 0

def cache_info():
with lock:
return getinfo()

wrapper = _cached_wrapper(func, cache, key, lock, make_info)
else:
if cache is None:

def wrapper(*args, **kwargs):
return func(*args, **kwargs)

def cache_clear():
pass

elif lock is None:

def wrapper(*args, **kwargs):
k = key(*args, **kwargs)
try:
return cache[k]
except KeyError:
pass # key not found
v = func(*args, **kwargs)
try:
cache[k] = v
except ValueError:
pass # value too large
return v

def cache_clear():
cache.clear()

else:

def wrapper(*args, **kwargs):
k = key(*args, **kwargs)
try:
with lock:
return cache[k]
except KeyError:
pass # key not found
v = func(*args, **kwargs)
# in case of a race, prefer the item already in the cache
try:
with lock:
return cache.setdefault(k, v)
except ValueError:
return v # value too large

def cache_clear():
with lock:
cache.clear()

cache_info = None
wrapper = _cached_wrapper(func, cache, key, lock, None)

wrapper.cache = cache
wrapper.cache_key = key
wrapper.cache_lock = lock
wrapper.cache_clear = cache_clear
wrapper.cache_info = cache_info

return functools.update_wrapper(wrapper, func)

Expand Down
153 changes: 153 additions & 0 deletions src/cachetools/_decorators.py
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,153 @@
"""Extensible memoizing decorator helpers."""


def _cached_locked_info(func, cache, key, lock, info):
hits = misses = 0

def wrapper(*args, **kwargs):
nonlocal hits, misses
k = key(*args, **kwargs)
try:
with lock:
result = cache[k]
hits += 1
return result
except KeyError:
with lock:
misses += 1
v = func(*args, **kwargs)
# in case of a race, prefer the item already in the cache
try:
with lock:
return cache.setdefault(k, v)
except ValueError:
return v # value too large

def cache_clear():
nonlocal hits, misses
with lock:
cache.clear()
hits = misses = 0

def cache_info():
with lock:
return info(hits, misses)

wrapper.cache_clear = cache_clear
wrapper.cache_info = cache_info
return wrapper


def _cached_unlocked_info(func, cache, key, info):
hits = misses = 0

def wrapper(*args, **kwargs):
nonlocal hits, misses
k = key(*args, **kwargs)
try:
result = cache[k]
hits += 1
return result
except KeyError:
misses += 1
v = func(*args, **kwargs)
try:
cache[k] = v
except ValueError:
pass # value too large
return v

def cache_clear():
nonlocal hits, misses
cache.clear()
hits = misses = 0

wrapper.cache_clear = cache_clear
wrapper.cache_info = lambda: info(hits, misses)
return wrapper


def _uncached_info(func, info):
misses = 0

def wrapper(*args, **kwargs):
nonlocal misses
misses += 1
return func(*args, **kwargs)

def cache_clear():
nonlocal misses
misses = 0

wrapper.cache_clear = cache_clear
wrapper.cache_info = lambda: info(0, misses)
return wrapper


def _cached_locked(func, cache, key, lock):
def wrapper(*args, **kwargs):
k = key(*args, **kwargs)
try:
with lock:
return cache[k]
except KeyError:
pass # key not found
v = func(*args, **kwargs)
# in case of a race, prefer the item already in the cache
try:
with lock:
return cache.setdefault(k, v)
except ValueError:
return v # value too large

def cache_clear():
with lock:
cache.clear()

wrapper.cache_clear = cache_clear
return wrapper


def _cached_unlocked(func, cache, key):
def wrapper(*args, **kwargs):
k = key(*args, **kwargs)
try:
return cache[k]
except KeyError:
pass # key not found
v = func(*args, **kwargs)
try:
cache[k] = v
except ValueError:
pass # value too large
return v

wrapper.cache_clear = lambda: cache.clear()
return wrapper


def _uncached(func):
def wrapper(*args, **kwargs):
return func(*args, **kwargs)

wrapper.cache_clear = lambda: None
return wrapper


def _cached_wrapper(func, cache, key, lock, info):
if info is not None:
if cache is None:
wrapper = _uncached_info(func, info)
elif lock is None:
wrapper = _cached_unlocked_info(func, cache, key, info)
else:
wrapper = _cached_locked_info(func, cache, key, lock, info)
else:
if cache is None:
wrapper = _uncached(func)
elif lock is None:
wrapper = _cached_unlocked(func, cache, key)
else:
wrapper = _cached_locked(func, cache, key, lock)
wrapper.cache_info = None
return wrapper

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