[Python-checkins] cpython: Issue #14373: Added C implementation of functools.lru_cache(). Based on
serhiy.storchaka
python-checkins at python.org
Sat May 23 21:43:13 CEST 2015
https://hg.python.org/cpython/rev/57776eee74f2
changeset: 96246:57776eee74f2
user: Serhiy Storchaka <storchaka at gmail.com>
date: Sat May 23 22:42:49 2015 +0300
summary:
Issue #14373: Added C implementation of functools.lru_cache(). Based on
patches by Matt Joiner and Alexey Kachayev.
files:
Lib/functools.py | 203 ++++----
Lib/test/test_functools.py | 109 ++++-
Misc/NEWS | 3 +
Modules/_functoolsmodule.c | 547 ++++++++++++++++++++++++-
4 files changed, 747 insertions(+), 115 deletions(-)
diff --git a/Lib/functools.py b/Lib/functools.py
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -419,120 +419,129 @@
if maxsize is not None and not isinstance(maxsize, int):
raise TypeError('Expected maxsize to be an integer or None')
+ def decorating_function(user_function):
+ wrapper = _lru_cache_wrapper(user_function, maxsize, typed, _CacheInfo)
+ return update_wrapper(wrapper, user_function)
+
+ return decorating_function
+
+def _lru_cache_wrapper(user_function, maxsize, typed, _CacheInfo):
# Constants shared by all lru cache instances:
sentinel = object() # unique object used to signal cache misses
make_key = _make_key # build a key from the function arguments
PREV, NEXT, KEY, RESULT = 0, 1, 2, 3 # names for the link fields
- def decorating_function(user_function):
- cache = {}
- hits = misses = 0
- full = False
- cache_get = cache.get # bound method to lookup a key or return None
- 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
+ cache = {}
+ hits = misses = 0
+ full = False
+ cache_get = cache.get # bound method to lookup a key or return None
+ 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
- if maxsize == 0:
+ if maxsize == 0:
- def wrapper(*args, **kwds):
- # No caching -- just a statistics update after a successful call
- nonlocal misses
- result = user_function(*args, **kwds)
- misses += 1
+ def wrapper(*args, **kwds):
+ # No caching -- just a statistics update after a successful call
+ nonlocal misses
+ result = user_function(*args, **kwds)
+ misses += 1
+ return result
+
+ elif maxsize is None:
+
+ def wrapper(*args, **kwds):
+ # Simple caching without ordering or size limit
+ nonlocal hits, misses
+ key = make_key(args, kwds, typed)
+ result = cache_get(key, sentinel)
+ if result is not sentinel:
+ hits += 1
return result
+ result = user_function(*args, **kwds)
+ cache[key] = result
+ misses += 1
+ return result
- elif maxsize is None:
+ else:
- def wrapper(*args, **kwds):
- # Simple caching without ordering or size limit
- nonlocal hits, misses
- key = make_key(args, kwds, typed)
- result = cache_get(key, sentinel)
- if result is not sentinel:
+ def wrapper(*args, **kwds):
+ # Size limited caching that tracks accesses by recency
+ nonlocal root, hits, misses, full
+ key = make_key(args, kwds, typed)
+ with lock:
+ link = cache_get(key)
+ if link is not None:
+ # Move the link to the front of the circular queue
+ 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
hits += 1
return result
- result = user_function(*args, **kwds)
- cache[key] = result
+ result = user_function(*args, **kwds)
+ with lock:
+ 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 full:
+ # 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.
+ # Keep a reference to the old key and old result to
+ # prevent their ref counts from going to zero during the
+ # update. That will prevent potentially arbitrary object
+ # clean-up code (i.e. __del__) from running while we're
+ # still adjusting the links.
+ root = oldroot[NEXT]
+ oldkey = root[KEY]
+ oldresult = root[RESULT]
+ root[KEY] = root[RESULT] = None
+ # Now update the cache dictionary.
+ del cache[oldkey]
+ # Save the potentially reentrant cache[key] assignment
+ # for last, after the root and links have been put in
+ # a consistent state.
+ cache[key] = oldroot
+ else:
+ # Put result in a new link at the front of the queue.
+ last = root[PREV]
+ link = [last, root, key, result]
+ last[NEXT] = root[PREV] = cache[key] = link
+ full = (len(cache) >= maxsize)
misses += 1
- return result
+ return result
- else:
+ def cache_info():
+ """Report cache statistics"""
+ with lock:
+ return _CacheInfo(hits, misses, maxsize, len(cache))
- def wrapper(*args, **kwds):
- # Size limited caching that tracks accesses by recency
- nonlocal root, hits, misses, full
- key = make_key(args, kwds, typed)
- with lock:
- link = cache_get(key)
- if link is not None:
- # Move the link to the front of the circular queue
- 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
- hits += 1
- return result
- result = user_function(*args, **kwds)
- with lock:
- 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 full:
- # 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.
- # Keep a reference to the old key and old result to
- # prevent their ref counts from going to zero during the
- # update. That will prevent potentially arbitrary object
- # clean-up code (i.e. __del__) from running while we're
- # still adjusting the links.
- root = oldroot[NEXT]
- oldkey = root[KEY]
- oldresult = root[RESULT]
- root[KEY] = root[RESULT] = None
- # Now update the cache dictionary.
- del cache[oldkey]
- # Save the potentially reentrant cache[key] assignment
- # for last, after the root and links have been put in
- # a consistent state.
- cache[key] = oldroot
- else:
- # Put result in a new link at the front of the queue.
- last = root[PREV]
- link = [last, root, key, result]
- last[NEXT] = root[PREV] = cache[key] = link
- full = (len(cache) >= maxsize)
- misses += 1
- return result
+ def cache_clear():
+ """Clear the cache and cache statistics"""
+ nonlocal hits, misses, full
+ with lock:
+ cache.clear()
+ root[:] = [root, root, None, None]
+ hits = misses = 0
+ full = False
- def cache_info():
- """Report cache statistics"""
- with lock:
- return _CacheInfo(hits, misses, maxsize, len(cache))
+ wrapper.cache_info = cache_info
+ wrapper.cache_clear = cache_clear
+ return update_wrapper(wrapper, user_function)
- def cache_clear():
- """Clear the cache and cache statistics"""
- nonlocal hits, misses, full
- with lock:
- cache.clear()
- root[:] = [root, root, None, None]
- hits = misses = 0
- full = False
-
- wrapper.cache_info = cache_info
- wrapper.cache_clear = cache_clear
- return update_wrapper(wrapper, user_function)
-
- return decorating_function
+try:
+ from _functools import _lru_cache_wrapper
+except ImportError:
+ pass
################################################################################
diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py
--- a/Lib/test/test_functools.py
+++ b/Lib/test/test_functools.py
@@ -7,6 +7,10 @@
from test import support
import unittest
from weakref import proxy
+try:
+ import threading
+except ImportError:
+ threading = None
import functools
@@ -912,12 +916,12 @@
return self.value == other.value
-class TestLRU(unittest.TestCase):
+class TestLRU:
def test_lru(self):
def orig(x, y):
return 3 * x + y
- f = functools.lru_cache(maxsize=20)(orig)
+ f = self.module.lru_cache(maxsize=20)(orig)
hits, misses, maxsize, currsize = f.cache_info()
self.assertEqual(maxsize, 20)
self.assertEqual(currsize, 0)
@@ -955,7 +959,7 @@
self.assertEqual(currsize, 1)
# test size zero (which means "never-cache")
- @functools.lru_cache(0)
+ @self.module.lru_cache(0)
def f():
nonlocal f_cnt
f_cnt += 1
@@ -971,7 +975,7 @@
self.assertEqual(currsize, 0)
# test size one
- @functools.lru_cache(1)
+ @self.module.lru_cache(1)
def f():
nonlocal f_cnt
f_cnt += 1
@@ -987,7 +991,7 @@
self.assertEqual(currsize, 1)
# test size two
- @functools.lru_cache(2)
+ @self.module.lru_cache(2)
def f(x):
nonlocal f_cnt
f_cnt += 1
@@ -1004,7 +1008,7 @@
self.assertEqual(currsize, 2)
def test_lru_with_maxsize_none(self):
- @functools.lru_cache(maxsize=None)
+ @self.module.lru_cache(maxsize=None)
def fib(n):
if n < 2:
return n
@@ -1012,17 +1016,26 @@
self.assertEqual([fib(n) for n in range(16)],
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610])
self.assertEqual(fib.cache_info(),
- functools._CacheInfo(hits=28, misses=16, maxsize=None, currsize=16))
+ self.module._CacheInfo(hits=28, misses=16, maxsize=None, currsize=16))
fib.cache_clear()
self.assertEqual(fib.cache_info(),
- functools._CacheInfo(hits=0, misses=0, maxsize=None, currsize=0))
+ self.module._CacheInfo(hits=0, misses=0, maxsize=None, currsize=0))
+
+ def test_lru_with_maxsize_negative(self):
+ @self.module.lru_cache(maxsize=-10)
+ def eq(n):
+ return n
+ for i in (0, 1):
+ self.assertEqual([eq(n) for n in range(150)], list(range(150)))
+ self.assertEqual(eq.cache_info(),
+ self.module._CacheInfo(hits=0, misses=300, maxsize=-10, currsize=1))
def test_lru_with_exceptions(self):
# Verify that user_function exceptions get passed through without
# creating a hard-to-read chained exception.
# http://bugs.python.org/issue13177
for maxsize in (None, 128):
- @functools.lru_cache(maxsize)
+ @self.module.lru_cache(maxsize)
def func(i):
return 'abc'[i]
self.assertEqual(func(0), 'a')
@@ -1035,7 +1048,7 @@
def test_lru_with_types(self):
for maxsize in (None, 128):
- @functools.lru_cache(maxsize=maxsize, typed=True)
+ @self.module.lru_cache(maxsize=maxsize, typed=True)
def square(x):
return x * x
self.assertEqual(square(3), 9)
@@ -1050,7 +1063,7 @@
self.assertEqual(square.cache_info().misses, 4)
def test_lru_with_keyword_args(self):
- @functools.lru_cache()
+ @self.module.lru_cache()
def fib(n):
if n < 2:
return n
@@ -1060,13 +1073,13 @@
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610]
)
self.assertEqual(fib.cache_info(),
- functools._CacheInfo(hits=28, misses=16, maxsize=128, currsize=16))
+ self.module._CacheInfo(hits=28, misses=16, maxsize=128, currsize=16))
fib.cache_clear()
self.assertEqual(fib.cache_info(),
- functools._CacheInfo(hits=0, misses=0, maxsize=128, currsize=0))
+ self.module._CacheInfo(hits=0, misses=0, maxsize=128, currsize=0))
def test_lru_with_keyword_args_maxsize_none(self):
- @functools.lru_cache(maxsize=None)
+ @self.module.lru_cache(maxsize=None)
def fib(n):
if n < 2:
return n
@@ -1074,15 +1087,71 @@
self.assertEqual([fib(n=number) for number in range(16)],
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610])
self.assertEqual(fib.cache_info(),
- functools._CacheInfo(hits=28, misses=16, maxsize=None, currsize=16))
+ self.module._CacheInfo(hits=28, misses=16, maxsize=None, currsize=16))
fib.cache_clear()
self.assertEqual(fib.cache_info(),
- functools._CacheInfo(hits=0, misses=0, maxsize=None, currsize=0))
+ self.module._CacheInfo(hits=0, misses=0, maxsize=None, currsize=0))
+
+ def test_lru_cache_decoration(self):
+ def f(zomg: 'zomg_annotation'):
+ """f doc string"""
+ return 42
+ g = self.module.lru_cache()(f)
+ for attr in self.module.WRAPPER_ASSIGNMENTS:
+ self.assertEqual(getattr(g, attr), getattr(f, attr))
+
+ @unittest.skipUnless(threading, 'This test requires threading.')
+ def test_lru_cache_threaded(self):
+ def orig(x, y):
+ return 3 * x + y
+ f = self.module.lru_cache(maxsize=20)(orig)
+ hits, misses, maxsize, currsize = f.cache_info()
+ self.assertEqual(currsize, 0)
+
+ def full(f, *args):
+ for _ in range(10):
+ f(*args)
+
+ def clear(f):
+ for _ in range(10):
+ f.cache_clear()
+
+ orig_si = sys.getswitchinterval()
+ sys.setswitchinterval(1e-6)
+ try:
+ # create 5 threads in order to fill cache
+ threads = []
+ for k in range(5):
+ t = threading.Thread(target=full, args=[f, k, k])
+ t.start()
+ threads.append(t)
+
+ for t in threads:
+ t.join()
+
+ hits, misses, maxsize, currsize = f.cache_info()
+ self.assertEqual(hits, 45)
+ self.assertEqual(misses, 5)
+ self.assertEqual(currsize, 5)
+
+ # create 5 threads in order to fill cache and 1 to clear it
+ cleaner = threading.Thread(target=clear, args=[f])
+ cleaner.start()
+ threads = [cleaner]
+ for k in range(5):
+ t = threading.Thread(target=full, args=[f, k, k])
+ t.start()
+ threads.append(t)
+
+ for t in threads:
+ t.join()
+ finally:
+ sys.setswitchinterval(orig_si)
def test_need_for_rlock(self):
# This will deadlock on an LRU cache that uses a regular lock
- @functools.lru_cache(maxsize=10)
+ @self.module.lru_cache(maxsize=10)
def test_func(x):
'Used to demonstrate a reentrant lru_cache call within a single thread'
return x
@@ -1110,6 +1179,12 @@
def f():
pass
+class TestLRUC(TestLRU, unittest.TestCase):
+ module = c_functools
+
+class TestLRUPy(TestLRU, unittest.TestCase):
+ module = py_functools
+
class TestSingleDispatch(unittest.TestCase):
def test_simple_overloads(self):
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -63,6 +63,9 @@
Library
-------
+- Issue #14373: Added C implementation of functools.lru_cache(). Based on
+ patches by Matt Joiner and Alexey Kachayev.
+
- Issue 24230: The tempfile module now accepts bytes for prefix, suffix and dir
parameters and returns bytes in such situations (matching the os module APIs).
diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -590,6 +590,539 @@
of the sequence in the calculation, and serves as a default when the\n\
sequence is empty.");
+/* lru_cache object **********************************************************/
+
+/* this object is used delimit args and keywords in the cache keys */
+static PyObject *kwd_mark = NULL;
+
+struct lru_list_elem;
+struct lru_cache_object;
+
+typedef struct lru_list_elem {
+ PyObject_HEAD
+ struct lru_list_elem *prev, *next; /* borrowed links */
+ PyObject *key, *result;
+} lru_list_elem;
+
+static void
+lru_list_elem_dealloc(lru_list_elem *link)
+{
+ _PyObject_GC_UNTRACK(link);
+ Py_XDECREF(link->key);
+ Py_XDECREF(link->result);
+ PyObject_GC_Del(link);
+}
+
+static int
+lru_list_elem_traverse(lru_list_elem *link, visitproc visit, void *arg)
+{
+ Py_VISIT(link->key);
+ Py_VISIT(link->result);
+ return 0;
+}
+
+static int
+lru_list_elem_clear(lru_list_elem *link)
+{
+ Py_CLEAR(link->key);
+ Py_CLEAR(link->result);
+ return 0;
+}
+
+static PyTypeObject lru_list_elem_type = {
+ PyVarObject_HEAD_INIT(&PyType_Type, 0)
+ "functools._lru_list_elem", /* tp_name */
+ sizeof(lru_list_elem), /* tp_basicsize */
+ 0, /* tp_itemsize */
+ /* methods */
+ (destructor)lru_list_elem_dealloc, /* tp_dealloc */
+ 0, /* tp_print */
+ 0, /* tp_getattr */
+ 0, /* tp_setattr */
+ 0, /* tp_reserved */
+ 0, /* tp_repr */
+ 0, /* tp_as_number */
+ 0, /* tp_as_sequence */
+ 0, /* tp_as_mapping */
+ 0, /* tp_hash */
+ 0, /* tp_call */
+ 0, /* tp_str */
+ 0, /* tp_getattro */
+ 0, /* tp_setattro */
+ 0, /* tp_as_buffer */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
+ 0, /* tp_doc */
+ (traverseproc)lru_list_elem_traverse, /* tp_traverse */
+ (inquiry)lru_list_elem_clear, /* tp_clear */
+};
+
+
+typedef PyObject *(*lru_cache_ternaryfunc)(struct lru_cache_object *, PyObject *, PyObject *);
+
+typedef struct lru_cache_object {
+ lru_list_elem root; /* includes PyObject_HEAD */
+ Py_ssize_t maxsize;
+ PyObject *maxsize_O;
+ PyObject *func;
+ lru_cache_ternaryfunc wrapper;
+ PyObject *cache;
+ PyObject *cache_info_type;
+ Py_ssize_t misses, hits;
+ int typed;
+ PyObject *dict;
+ int full;
+} lru_cache_object;
+
+static PyTypeObject lru_cache_type;
+
+static PyObject *
+lru_cache_make_key(PyObject *args, PyObject *kwds, int typed)
+{
+ PyObject *key, *sorted_items;
+ Py_ssize_t key_size, pos, key_pos;
+
+ /* short path, key will match args anyway, which is a tuple */
+ if (!typed && !kwds) {
+ Py_INCREF(args);
+ return args;
+ }
+
+ if (kwds && PyDict_Size(kwds) > 0) {
+ sorted_items = PyDict_Items(kwds);
+ if (!sorted_items)
+ return NULL;
+ if (PyList_Sort(sorted_items) < 0) {
+ Py_DECREF(sorted_items);
+ return NULL;
+ }
+ } else
+ sorted_items = NULL;
+
+ key_size = PyTuple_GET_SIZE(args);
+ if (sorted_items)
+ key_size += PyList_GET_SIZE(sorted_items);
+ if (typed)
+ key_size *= 2;
+ if (sorted_items)
+ key_size++;
+
+ key = PyTuple_New(key_size);
+ if (key == NULL)
+ goto done;
+
+ key_pos = 0;
+ for (pos = 0; pos < PyTuple_GET_SIZE(args); ++pos) {
+ PyObject *item = PyTuple_GET_ITEM(args, pos);
+ Py_INCREF(item);
+ PyTuple_SET_ITEM(key, key_pos++, item);
+ }
+ if (sorted_items) {
+ Py_INCREF(kwd_mark);
+ PyTuple_SET_ITEM(key, key_pos++, kwd_mark);
+ for (pos = 0; pos < PyList_GET_SIZE(sorted_items); ++pos) {
+ PyObject *item = PyList_GET_ITEM(sorted_items, pos);
+ Py_INCREF(item);
+ PyTuple_SET_ITEM(key, key_pos++, item);
+ }
+ }
+ if (typed) {
+ for (pos = 0; pos < PyTuple_GET_SIZE(args); ++pos) {
+ PyObject *item = (PyObject *)Py_TYPE(PyTuple_GET_ITEM(args, pos));
+ Py_INCREF(item);
+ PyTuple_SET_ITEM(key, key_pos++, item);
+ }
+ if (sorted_items) {
+ for (pos = 0; pos < PyList_GET_SIZE(sorted_items); ++pos) {
+ PyObject *tp_items = PyList_GET_ITEM(sorted_items, pos);
+ PyObject *item = (PyObject *)Py_TYPE(PyTuple_GET_ITEM(tp_items, 1));
+ Py_INCREF(item);
+ PyTuple_SET_ITEM(key, key_pos++, item);
+ }
+ }
+ }
+ assert(key_pos == key_size);
+
+done:
+ if (sorted_items)
+ Py_DECREF(sorted_items);
+ return key;
+}
+
+static PyObject *
+uncached_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds)
+{
+ PyObject *result = PyObject_Call(self->func, args, kwds);
+ if (!result)
+ return NULL;
+ self->misses++;
+ return result;
+}
+
+static PyObject *
+infinite_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds)
+{
+ PyObject *result;
+ PyObject *key = lru_cache_make_key(args, kwds, self->typed);
+ if (!key)
+ return NULL;
+ result = PyDict_GetItemWithError(self->cache, key);
+ if (result) {
+ Py_INCREF(result);
+ self->hits++;
+ Py_DECREF(key);
+ return result;
+ }
+ if (PyErr_Occurred()) {
+ Py_DECREF(key);
+ return NULL;
+ }
+ result = PyObject_Call(self->func, args, kwds);
+ if (!result) {
+ Py_DECREF(key);
+ return NULL;
+ }
+ if (PyDict_SetItem(self->cache, key, result) < 0) {
+ Py_DECREF(result);
+ Py_DECREF(key);
+ return NULL;
+ }
+ Py_DECREF(key);
+ self->misses++;
+ return result;
+}
+
+static void
+lru_cache_extricate_link(lru_list_elem *link)
+{
+ link->prev->next = link->next;
+ link->next->prev = link->prev;
+}
+
+static void
+lru_cache_append_link(lru_cache_object *self, lru_list_elem *link)
+{
+ lru_list_elem *root = &self->root;
+ lru_list_elem *last = root->prev;
+ last->next = root->prev = link;
+ link->prev = last;
+ link->next = root;
+}
+
+static PyObject *
+bounded_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds)
+{
+ lru_list_elem *link;
+ PyObject *key, *result;
+
+ key = lru_cache_make_key(args, kwds, self->typed);
+ if (!key)
+ return NULL;
+ link = (lru_list_elem *)PyDict_GetItemWithError(self->cache, key);
+ if (link) {
+ lru_cache_extricate_link(link);
+ lru_cache_append_link(self, link);
+ self->hits++;
+ result = link->result;
+ Py_INCREF(result);
+ Py_DECREF(key);
+ return result;
+ }
+ if (PyErr_Occurred()) {
+ Py_DECREF(key);
+ return NULL;
+ }
+ result = PyObject_Call(self->func, args, kwds);
+ if (!result) {
+ Py_DECREF(key);
+ return NULL;
+ }
+ if (self->full && self->root.next != &self->root) {
+ /* Use the oldest item to store the new key and result. */
+ PyObject *oldkey, *oldresult;
+ /* Extricate the oldest item. */
+ link = self->root.next;
+ lru_cache_extricate_link(link);
+ /* Remove it from the cache.
+ The cache dict holds one reference to the link,
+ and the linked list holds yet one reference to it. */
+ if (PyDict_DelItem(self->cache, link->key) < 0) {
+ lru_cache_append_link(self, link);
+ Py_DECREF(key);
+ Py_DECREF(result);
+ return NULL;
+ }
+ /* Keep a reference to the old key and old result to
+ prevent their ref counts from going to zero during the
+ update. That will prevent potentially arbitrary object
+ clean-up code (i.e. __del__) from running while we're
+ still adjusting the links. */
+ oldkey = link->key;
+ oldresult = link->result;
+
+ link->key = key;
+ link->result = result;
+ if (PyDict_SetItem(self->cache, key, (PyObject *)link) < 0) {
+ Py_DECREF(link);
+ Py_DECREF(oldkey);
+ Py_DECREF(oldresult);
+ return NULL;
+ }
+ lru_cache_append_link(self, link);
+ Py_INCREF(result); /* for return */
+ Py_DECREF(oldkey);
+ Py_DECREF(oldresult);
+ } else {
+ /* Put result in a new link at the front of the queue. */
+ link = (lru_list_elem *)PyObject_GC_New(lru_list_elem,
+ &lru_list_elem_type);
+ if (link == NULL) {
+ Py_DECREF(key);
+ Py_DECREF(result);
+ return NULL;
+ }
+
+ link->key = key;
+ link->result = result;
+ _PyObject_GC_TRACK(link);
+ if (PyDict_SetItem(self->cache, key, (PyObject *)link) < 0) {
+ Py_DECREF(link);
+ return NULL;
+ }
+ lru_cache_append_link(self, link);
+ Py_INCREF(result); /* for return */
+ self->full = (PyDict_Size(self->cache) >= self->maxsize);
+ }
+ self->misses++;
+ return result;
+}
+
+static PyObject *
+lru_cache_new(PyTypeObject *type, PyObject *args, PyObject *kw)
+{
+ PyObject *func, *maxsize_O, *cache_info_type;
+ int typed;
+ lru_cache_object *obj;
+ Py_ssize_t maxsize;
+ PyObject *(*wrapper)(lru_cache_object *, PyObject *, PyObject *);
+ static char *keywords[] = {"user_function", "maxsize", "typed",
+ "cache_info_type", NULL};
+
+ if (!PyArg_ParseTupleAndKeywords(args, kw, "OOpO:lru_cache", keywords,
+ &func, &maxsize_O, &typed,
+ &cache_info_type)) {
+ return NULL;
+ }
+
+ if (!PyCallable_Check(func)) {
+ PyErr_SetString(PyExc_TypeError,
+ "the first argument must be callable");
+ return NULL;
+ }
+
+ /* select the caching function, and make/inc maxsize_O */
+ if (maxsize_O == Py_None) {
+ wrapper = infinite_lru_cache_wrapper;
+ /* use this only to initialize lru_cache_object attribute maxsize */
+ maxsize = -1;
+ } else if (PyIndex_Check(maxsize_O)) {
+ maxsize = PyNumber_AsSsize_t(maxsize_O, PyExc_OverflowError);
+ if (maxsize == -1 && PyErr_Occurred())
+ return NULL;
+ if (maxsize == 0)
+ wrapper = uncached_lru_cache_wrapper;
+ else
+ wrapper = bounded_lru_cache_wrapper;
+ } else {
+ PyErr_SetString(PyExc_TypeError, "maxsize should be integer or None");
+ return NULL;
+ }
+
+ obj = (lru_cache_object *)type->tp_alloc(type, 0);
+ if (obj == NULL)
+ return NULL;
+
+ if (!(obj->cache = PyDict_New())) {
+ Py_DECREF(obj);
+ return NULL;
+ }
+
+ obj->root.prev = &obj->root;
+ obj->root.next = &obj->root;
+ obj->maxsize = maxsize;
+ Py_INCREF(maxsize_O);
+ obj->maxsize_O = maxsize_O;
+ Py_INCREF(func);
+ obj->func = func;
+ obj->wrapper = wrapper;
+ obj->misses = obj->hits = 0;
+ obj->typed = typed;
+ Py_INCREF(cache_info_type);
+ obj->cache_info_type = cache_info_type;
+
+ return (PyObject *)obj;
+}
+
+static lru_list_elem *
+lru_cache_unlink_list(lru_cache_object *self)
+{
+ lru_list_elem *root = &self->root;
+ lru_list_elem *link = root->next;
+ if (link == root)
+ return NULL;
+ root->prev->next = NULL;
+ root->next = root->prev = root;
+ return link;
+}
+
+static void
+lru_cache_clear_list(lru_list_elem *link)
+{
+ while (link != NULL) {
+ lru_list_elem *next = link->next;
+ Py_DECREF(link);
+ link = next;
+ }
+}
+
+static void
+lru_cache_dealloc(lru_cache_object *obj)
+{
+ lru_list_elem *list = lru_cache_unlink_list(obj);
+ Py_XDECREF(obj->maxsize_O);
+ Py_XDECREF(obj->func);
+ Py_XDECREF(obj->cache);
+ Py_XDECREF(obj->dict);
+ Py_XDECREF(obj->cache_info_type);
+ lru_cache_clear_list(list);
+ Py_TYPE(obj)->tp_free(obj);
+}
+
+static PyObject *
+lru_cache_call(lru_cache_object *self, PyObject *args, PyObject *kwds)
+{
+ return self->wrapper(self, args, kwds);
+}
+
+static PyObject *
+lru_cache_cache_info(lru_cache_object *self, PyObject *unused)
+{
+ return PyObject_CallFunction(self->cache_info_type, "nnOn",
+ self->hits, self->misses, self->maxsize_O,
+ PyDict_Size(self->cache));
+}
+
+static PyObject *
+lru_cache_cache_clear(lru_cache_object *self, PyObject *unused)
+{
+ lru_list_elem *list = lru_cache_unlink_list(self);
+ self->hits = self->misses = 0;
+ self->full = 0;
+ PyDict_Clear(self->cache);
+ lru_cache_clear_list(list);
+ Py_RETURN_NONE;
+}
+
+static int
+lru_cache_tp_traverse(lru_cache_object *self, visitproc visit, void *arg)
+{
+ lru_list_elem *link = self->root.next;
+ while (link != &self->root) {
+ lru_list_elem *next = link->next;
+ Py_VISIT(link);
+ link = next;
+ }
+ Py_VISIT(self->maxsize_O);
+ Py_VISIT(self->func);
+ Py_VISIT(self->cache);
+ Py_VISIT(self->cache_info_type);
+ Py_VISIT(self->dict);
+ return 0;
+}
+
+static int
+lru_cache_tp_clear(lru_cache_object *self)
+{
+ lru_list_elem *list = lru_cache_unlink_list(self);
+ Py_CLEAR(self->maxsize_O);
+ Py_CLEAR(self->func);
+ Py_CLEAR(self->cache);
+ Py_CLEAR(self->cache_info_type);
+ Py_CLEAR(self->dict);
+ lru_cache_clear_list(list);
+ return 0;
+}
+
+
+PyDoc_STRVAR(lru_cache_doc,
+"Create a cached callable that wraps another function.\n\
+\n\
+user_function: the function being cached\n\
+\n\
+maxsize: 0 for no caching\n\
+ None for unlimited cache size\n\
+ n for a bounded cache\n\
+\n\
+typed: False cache f(3) and f(3.0) as identical calls\n\
+ True cache f(3) and f(3.0) as distinct calls\n\
+\n\
+cache_info_type: namedtuple class with the fields:\n\
+ hits misses currsize maxsize\n"
+);
+
+static PyMethodDef lru_cache_methods[] = {
+ {"cache_info", (PyCFunction)lru_cache_cache_info, METH_NOARGS},
+ {"cache_clear", (PyCFunction)lru_cache_cache_clear, METH_NOARGS},
+ {NULL}
+};
+
+static PyGetSetDef lru_cache_getsetlist[] = {
+ {"__dict__", PyObject_GenericGetDict, PyObject_GenericSetDict},
+ {NULL}
+};
+
+static PyTypeObject lru_cache_type = {
+ PyVarObject_HEAD_INIT(NULL, 0)
+ "functools._lru_cache_wrapper", /* tp_name */
+ sizeof(lru_cache_object), /* tp_basicsize */
+ 0, /* tp_itemsize */
+ /* methods */
+ (destructor)lru_cache_dealloc, /* tp_dealloc */
+ 0, /* tp_print */
+ 0, /* tp_getattr */
+ 0, /* tp_setattr */
+ 0, /* tp_reserved */
+ 0, /* tp_repr */
+ 0, /* tp_as_number */
+ 0, /* tp_as_sequence */
+ 0, /* tp_as_mapping */
+ 0, /* tp_hash */
+ (ternaryfunc)lru_cache_call, /* tp_call */
+ 0, /* tp_str */
+ 0, /* tp_getattro */
+ 0, /* tp_setattro */
+ 0, /* tp_as_buffer */
+ Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE|Py_TPFLAGS_HAVE_GC,
+ /* tp_flags */
+ lru_cache_doc, /* tp_doc */
+ (traverseproc)lru_cache_tp_traverse,/* tp_traverse */
+ (inquiry)lru_cache_tp_clear, /* tp_clear */
+ 0, /* tp_richcompare */
+ 0, /* tp_weaklistoffset */
+ 0, /* tp_iter */
+ 0, /* tp_iternext */
+ lru_cache_methods, /* tp_methods */
+ 0, /* tp_members */
+ lru_cache_getsetlist, /* tp_getset */
+ 0, /* tp_base */
+ 0, /* tp_dict */
+ 0, /* tp_descr_get */
+ 0, /* tp_descr_set */
+ offsetof(lru_cache_object, dict), /* tp_dictoffset */
+ 0, /* tp_init */
+ 0, /* tp_alloc */
+ lru_cache_new, /* tp_new */
+};
+
/* module level code ********************************************************/
PyDoc_STRVAR(module_doc,
@@ -602,6 +1135,11 @@
{NULL, NULL} /* sentinel */
};
+static void
+module_free(void *m)
+{
+ Py_CLEAR(kwd_mark);
+}
static struct PyModuleDef _functoolsmodule = {
PyModuleDef_HEAD_INIT,
@@ -612,7 +1150,7 @@
NULL,
NULL,
NULL,
- NULL
+ module_free,
};
PyMODINIT_FUNC
@@ -623,6 +1161,7 @@
char *name;
PyTypeObject *typelist[] = {
&partial_type,
+ &lru_cache_type,
NULL
};
@@ -630,6 +1169,12 @@
if (m == NULL)
return NULL;
+ kwd_mark = PyObject_CallObject((PyObject *)&PyBaseObject_Type, NULL);
+ if (!kwd_mark) {
+ Py_DECREF(m);
+ return NULL;
+ }
+
for (i=0 ; typelist[i] != NULL ; i++) {
if (PyType_Ready(typelist[i]) < 0) {
Py_DECREF(m);
--
Repository URL: https://hg.python.org/cpython
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