diff --git a/Lib/functools.py b/Lib/functools.py index 19c25e1c053..09df0680208 100644 --- a/Lib/functools.py +++ b/Lib/functools.py @@ -419,120 +419,129 @@ def lru_cache(maxsize=128, typed=False): 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 index 03dd5457368..271d655dd09 100644 --- a/Lib/test/test_functools.py +++ b/Lib/test/test_functools.py @@ -7,6 +7,10 @@ import sys from test import support import unittest from weakref import proxy +try: + import threading +except ImportError: + threading = None import functools @@ -912,12 +916,12 @@ class Orderable_LT: 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 @@ class TestLRU(unittest.TestCase): 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 @@ class TestLRU(unittest.TestCase): 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 @@ class TestLRU(unittest.TestCase): 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 @@ class TestLRU(unittest.TestCase): 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 @@ class TestLRU(unittest.TestCase): 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 @@ class TestLRU(unittest.TestCase): 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 @@ class TestLRU(unittest.TestCase): 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 @@ class TestLRU(unittest.TestCase): [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 @@ class TestLRU(unittest.TestCase): 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 @@ class TestLRU(unittest.TestCase): 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 index 88818b65794..abda41d8723 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -65,6 +65,9 @@ Core and Builtins 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 index 3c82e5134a4..99b50b0e9d3 100644 --- a/Modules/_functoolsmodule.c +++ b/Modules/_functoolsmodule.c @@ -590,6 +590,539 @@ For example, reduce(lambda x, y: x+y, [1, 2, 3, 4, 5]) calculates\n\ 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 @@ static PyMethodDef module_methods[] = { {NULL, NULL} /* sentinel */ }; +static void +module_free(void *m) +{ + Py_CLEAR(kwd_mark); +} static struct PyModuleDef _functoolsmodule = { PyModuleDef_HEAD_INIT, @@ -612,7 +1150,7 @@ static struct PyModuleDef _functoolsmodule = { NULL, NULL, NULL, - NULL + module_free, }; PyMODINIT_FUNC @@ -623,6 +1161,7 @@ PyInit__functools(void) char *name; PyTypeObject *typelist[] = { &partial_type, + &lru_cache_type, NULL }; @@ -630,6 +1169,12 @@ PyInit__functools(void) 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);