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Code Issues 32 Releases Wiki Activity

Fixed #21351 -- Replaced memoize with Python's lru_cache.

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Replaced the custom, untested memoize with a similar decorator from Python's
3.2 stdlib. Although some minor performance degradation (see ticket), it is
expected that in the long run lru_cache will outperform memoize once it is
implemented in C.

Thanks to EvilDMP for the report and Baptiste Mispelon for the idea of
replacing memoize with lru_cache.
This commit is contained in:
Bouke Haarsma
2013-11-01 21:15:41 +01:00
committed by Baptiste Mispelon
parent 6c5f5b9a41
commit 9b7455e918
13 changed files with 254 additions and 38 deletions
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10
django/contrib/staticfiles/finders.py
View File

@@ -4,16 +4,14 @@ import os
from django.conf import settings
from django.core.exceptions import ImproperlyConfigured
from django.core.files.storage import default_storage, Storage, FileSystemStorage
from django.utils.functional import empty, memoize, LazyObject
from django.utils.functional import empty, LazyObject
from django.utils.module_loading import import_by_path
from django.utils._os import safe_join
from django.utils import six
from django.utils import six, lru_cache
from django.contrib.staticfiles import utils
from django.contrib.staticfiles.storage import AppStaticStorage
_finders = OrderedDict()
class BaseFinder(object):
"""
@@ -254,7 +252,8 @@ def get_finders():
yield get_finder(finder_path)
def _get_finder(import_path):
@lru_cache.lru_cache(maxsize=None)
def get_finder(import_path):
"""
Imports the staticfiles finder class described by import_path, where
import_path is the full Python path to the class.
@@ -264,4 +263,3 @@ def _get_finder(import_path):
raise ImproperlyConfigured('Finder "%s" is not a subclass of "%s"' %
(Finder, BaseFinder))
return Finder()
get_finder = memoize(_get_finder, _finders, 1)

9
django/core/management/commands/loaddata.py
View File

@@ -14,8 +14,9 @@ from django.core.management.color import no_style
from django.db import (connections, router, transaction, DEFAULT_DB_ALIAS,
IntegrityError, DatabaseError)
from django.db.models import get_app_paths
from django.utils import lru_cache
from django.utils.encoding import force_text
from django.utils.functional import cached_property, memoize
from django.utils.functional import cached_property
from django.utils._os import upath
from itertools import product
@@ -164,7 +165,8 @@ class Command(BaseCommand):
RuntimeWarning
)
def _find_fixtures(self, fixture_label):
@lru_cache.lru_cache(maxsize=None)
def find_fixtures(self, fixture_label):
"""
Finds fixture files for a given label.
"""
@@ -220,9 +222,6 @@ class Command(BaseCommand):
return fixture_files
_label_to_fixtures_cache = {}
find_fixtures = memoize(_find_fixtures, _label_to_fixtures_cache, 2)
@cached_property
def fixture_dirs(self):
"""

23
django/core/urlresolvers.py
View File

@@ -16,18 +16,14 @@ from django.http import Http404
from django.core.exceptions import ImproperlyConfigured, ViewDoesNotExist
from django.utils.datastructures import MultiValueDict
from django.utils.encoding import force_str, force_text, iri_to_uri
from django.utils.functional import memoize, lazy
from django.utils.functional import lazy
from django.utils.http import urlquote
from django.utils.module_loading import module_has_submodule
from django.utils.regex_helper import normalize
from django.utils import six
from django.utils import six, lru_cache
from django.utils.translation import get_language
_resolver_cache = {} # Maps URLconf modules to RegexURLResolver instances.
_ns_resolver_cache = {} # Maps namespaces to RegexURLResolver instances.
_callable_cache = {} # Maps view and url pattern names to their view functions.
# SCRIPT_NAME prefixes for each thread are stored here. If there's no entry for
# the current thread (which is the only one we ever access), it is assumed to
# be empty.
@@ -80,6 +76,7 @@ class NoReverseMatch(Exception):
pass
@lru_cache.lru_cache(maxsize=None)
def get_callable(lookup_view, can_fail=False):
"""
Convert a string version of a function name to the callable object.
@@ -119,17 +116,17 @@ def get_callable(lookup_view, can_fail=False):
"Could not import %s. View does not exist in module %s." %
(lookup_view, mod_name))
return lookup_view
get_callable = memoize(get_callable, _callable_cache, 1)
@lru_cache.lru_cache(maxsize=None)
def get_resolver(urlconf):
if urlconf is None:
from django.conf import settings
urlconf = settings.ROOT_URLCONF
return RegexURLResolver(r'^/', urlconf)
get_resolver = memoize(get_resolver, _resolver_cache, 1)
@lru_cache.lru_cache(maxsize=None)
def get_ns_resolver(ns_pattern, resolver):
# Build a namespaced resolver for the given parent urlconf pattern.
# This makes it possible to have captured parameters in the parent
@@ -137,7 +134,6 @@ def get_ns_resolver(ns_pattern, resolver):
ns_resolver = RegexURLResolver(ns_pattern,
resolver.url_patterns)
return RegexURLResolver(r'^/', [ns_resolver])
get_ns_resolver = memoize(get_ns_resolver, _ns_resolver_cache, 2)
def get_mod_func(callback):
@@ -523,12 +519,9 @@ reverse_lazy = lazy(reverse, str)
def clear_url_caches():
global _resolver_cache
global _ns_resolver_cache
global _callable_cache
_resolver_cache.clear()
_ns_resolver_cache.clear()
_callable_cache.clear()
get_callable.cache_clear()
get_resolver.cache_clear()
get_ns_resolver.cache_clear()
def set_script_prefix(prefix):

2
django/test/utils.py
View File

@@ -427,7 +427,7 @@ class TransRealMixin(object):
trans_real._translations = {}
trans_real._active = local()
trans_real._default = None
trans_real._checked_languages = {}
trans_real.check_for_language.cache_clear()
def tearDown(self):
self.flush_caches()

5
django/utils/functional.py
View File

@@ -2,6 +2,7 @@ import copy
import operator
from functools import wraps
import sys
import warnings
from django.utils import six
from django.utils.six.moves import copyreg
@@ -24,6 +25,10 @@ def memoize(func, cache, num_args):
Only the first num_args are considered when creating the key.
"""
warnings.warn(u"memoize wrapper is deprecated and will be removed in "
u"Django 1.9. Use django.utils.lru_cache instead.",
PendingDeprecationWarning, 2)
@wraps(func)
def wrapper(*args):
mem_args = args[:num_args]

173
django/utils/lru_cache.py Normal file
View File

@@ -0,0 +1,173 @@
try:
from functools import lru_cache
except ImportError:
# backport of Python's 3.2 lru_cache, written by Raymond Hettinger and
# licensed under MIT license, from:
# <http://code.activestate.com/recipes/578078-py26-and-py30-backport-of-python-33s-lru-cache/>
# Should be removed when Django only supports Python 3.2 and above.
from collections import namedtuple
from functools import update_wrapper
from threading import RLock
_CacheInfo = namedtuple("CacheInfo", ["hits", "misses", "maxsize", "currsize"])
class _HashedSeq(list):
__slots__ = 'hashvalue'
def __init__(self, tup, hash=hash):
self[:] = tup
self.hashvalue = hash(tup)
def __hash__(self):
return self.hashvalue
def _make_key(args, kwds, typed,
kwd_mark = (object(),),
fasttypes = {int, str, frozenset, type(None)},
sorted=sorted, tuple=tuple, type=type, len=len):
'Make a cache key from optionally typed positional and keyword arguments'
key = args
if kwds:
sorted_items = sorted(kwds.items())
key += kwd_mark
for item in sorted_items:
key += item
if typed:
key += tuple(type(v) for v in args)
if kwds:
key += tuple(type(v) for k, v in sorted_items)
elif len(key) == 1 and type(key[0]) in fasttypes:
return key[0]
return _HashedSeq(key)
def lru_cache(maxsize=100, typed=False):
"""Least-recently-used cache decorator.
If *maxsize* is set to None, the LRU features are disabled and the cache
can grow without bound.
If *typed* is True, arguments of different types will be cached separately.
For example, f(3.0) and f(3) will be treated as distinct calls with
distinct results.
Arguments to the cached function must be hashable.
View the cache statistics named tuple (hits, misses, maxsize, currsize) with
f.cache_info(). Clear the cache and statistics with f.cache_clear().
Access the underlying function with f.__wrapped__.
See: http://en.wikipedia.org/wiki/Cache_algorithms#Least_Recently_Used
"""
# Users should only access the lru_cache through its public API:
# 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).
def decorating_function(user_function):
cache = dict()
stats = [0, 0] # make statistics updateable non-locally
HITS, MISSES = 0, 1 # names for the stats fields
make_key = _make_key
cache_get = cache.get # bound method to lookup key or return None
_len = len # localize the global len() function
lock = RLock() # because linkedlist updates aren't threadsafe
root = [] # root of the circular doubly linked list
root[:] = [root, root, None, None] # initialize by pointing to self
nonlocal_root = [root] # make updateable non-locally
PREV, NEXT, KEY, RESULT = 0, 1, 2, 3 # names for the link fields
if maxsize == 0:
def wrapper(*args, **kwds):
# no caching, just do a statistics update after a successful call
result = user_function(*args, **kwds)
stats[MISSES] += 1
return result
elif maxsize is None:
def wrapper(*args, **kwds):
# simple caching without ordering or size limit
key = make_key(args, kwds, typed)
result = cache_get(key, root) # root used here as a unique not-found sentinel
if result is not root:
stats[HITS] += 1
return result
result = user_function(*args, **kwds)
cache[key] = result
stats[MISSES] += 1
return result
else:
def wrapper(*args, **kwds):
# size limited caching that tracks accesses by recency
key = make_key(args, kwds, typed) if kwds or typed else args
with lock:
link = cache_get(key)
if link is not None:
# record recent use of the key by moving it to the front of the list
root, = nonlocal_root
link_prev, link_next, key, result = link
link_prev[NEXT] = link_next
link_next[PREV] = link_prev
last = root[PREV]
last[NEXT] = root[PREV] = link
link[PREV] = last
link[NEXT] = root
stats[HITS] += 1
return result
result = user_function(*args, **kwds)
with lock:
root, = nonlocal_root
if key in cache:
# getting here means that this same key was added to the
# cache while the lock was released. since the link
# update is already done, we need only return the
# computed result and update the count of misses.
pass
elif _len(cache) >= maxsize:
# use the old root to store the new key and result
oldroot = root
oldroot[KEY] = key
oldroot[RESULT] = result
# empty the oldest link and make it the new root
root = nonlocal_root[0] = oldroot[NEXT]
oldkey = root[KEY]
oldvalue = root[RESULT]
root[KEY] = root[RESULT] = None
# now update the cache dictionary for the new links
del cache[oldkey]
cache[key] = oldroot
else:
# put result in a new link at the front of the list
last = root[PREV]
link = [last, root, key, result]
last[NEXT] = root[PREV] = cache[key] = link
stats[MISSES] += 1
return result
def cache_info():
"""Report cache statistics"""
with lock:
return _CacheInfo(stats[HITS], stats[MISSES], maxsize, len(cache))
def cache_clear():
"""Clear the cache and cache statistics"""
with lock:
cache.clear()
root = nonlocal_root[0]
root[:] = [root, root, None, None]
stats[:] = [0, 0]
wrapper.__wrapped__ = user_function
wrapper.cache_info = cache_info
wrapper.cache_clear = cache_clear
return update_wrapper(wrapper, user_function)
return decorating_function

6
django/utils/translation/trans_real.py
View File

@@ -14,10 +14,9 @@ import warnings
from django.dispatch import receiver
from django.test.signals import setting_changed
from django.utils.encoding import force_str, force_text
from django.utils.functional import memoize
from django.utils._os import upath
from django.utils.safestring import mark_safe, SafeData
from django.utils import six
from django.utils import six, lru_cache
from django.utils.six import StringIO
from django.utils.translation import TranslatorCommentWarning, trim_whitespace
@@ -33,7 +32,6 @@ _default = None
# This is a cache for normalized accept-header languages to prevent multiple
# file lookups when checking the same locale on repeated requests.
_accepted = {}
_checked_languages = {}
# magic gettext number to separate context from message
CONTEXT_SEPARATOR = "\x04"
@@ -390,6 +388,7 @@ def all_locale_paths():
return [globalpath] + list(settings.LOCALE_PATHS)
@lru_cache.lru_cache(maxsize=None)
def check_for_language(lang_code):
"""
Checks whether there is a global language file for the given language
@@ -401,7 +400,6 @@ def check_for_language(lang_code):
if gettext_module.find('django', path, [to_locale(lang_code)]) is not None:
return True
return False
check_for_language = memoize(check_for_language, _checked_languages, 1)
def get_supported_language_variant(lang_code, supported=None, strict=False):