#include "Python.h"

#include "pycore_call.h" // _PyObject_CallNoArgs()

#include "pycore_dict.h" // _PyDict_Pop_KnownHash()

#include "pycore_long.h" // _PyLong_GetZero()

#include "pycore_moduleobject.h" // _PyModule_GetState()

#include "pycore_object.h" // _PyObject_GC_TRACK

#include "pycore_pystate.h" // _PyThreadState_GET()

#include "pycore_tuple.h" // _PyTuple_ITEMS()

#include "pycore_weakref.h" // FT_CLEAR_WEAKREFS()

#include "clinic/_functoolsmodule.c.h"

/*[clinic input]

module _functools

class _functools._lru_cache_wrapper "PyObject *" "&lru_cache_type_spec"

[clinic start generated code]*/

/*[clinic end generated code: output=da39a3ee5e6b4b0d input=bece4053896b09c0]*/

/* _functools module written and maintained

by Hye-Shik Chang <perky@FreeBSD.org>

with adaptations by Raymond Hettinger <python@rcn.com>

Copyright (c) 2004, 2005, 2006 Python Software Foundation.

All rights reserved.

*/

typedef struct _functools_state {

/* this object is used delimit args and keywords in the cache keys */

PyObject *kwd_mark;

PyTypeObject *partial_type;

PyTypeObject *keyobject_type;

PyTypeObject *lru_list_elem_type;

} _functools_state;

static inline _functools_state *

get_functools_state(PyObject *module)

{

void *state = _PyModule_GetState(module);

assert(state != NULL);

return (_functools_state *)state;

}

/* partial object **********************************************************/

typedef struct {

PyObject_HEAD

PyObject *fn;

PyObject *args;

PyObject *kw;

PyObject *dict; /* __dict__ */

PyObject *weakreflist; /* List of weak references */

vectorcallfunc vectorcall;

} partialobject;

static void partial_setvectorcall(partialobject *pto);

static struct PyModuleDef _functools_module;

static PyObject *

partial_call(partialobject *pto, PyObject *args, PyObject *kwargs);

static inline _functools_state *

get_functools_state_by_type(PyTypeObject *type)

{

PyObject *module = PyType_GetModuleByDef(type, &_functools_module);

if (module == NULL) {

return NULL;

}

return get_functools_state(module);

}

// Not converted to argument clinic, because of `*args, **kwargs` arguments.

static PyObject *

partial_new(PyTypeObject *type, PyObject *args, PyObject *kw)

{

PyObject *func, *pargs, *nargs, *pkw;

partialobject *pto;

if (PyTuple_GET_SIZE(args) < 1) {

PyErr_SetString(PyExc_TypeError,

"type 'partial' takes at least one argument");

return NULL;

}

_functools_state *state = get_functools_state_by_type(type);

if (state == NULL) {

return NULL;

}

pargs = pkw = NULL;

func = PyTuple_GET_ITEM(args, 0);

int res = PyObject_TypeCheck(func, state->partial_type);

if (res == -1) {

return NULL;

}

if (res == 1) {

// We can use its underlying function directly and merge the arguments.

partialobject *part = (partialobject *)func;

if (part->dict == NULL) {

pargs = part->args;

pkw = part->kw;

func = part->fn;

assert(PyTuple_Check(pargs));

assert(PyDict_Check(pkw));

}

}

if (!PyCallable_Check(func)) {

PyErr_SetString(PyExc_TypeError,

"the first argument must be callable");

return NULL;

}

/* create partialobject structure */

pto = (partialobject *)type->tp_alloc(type, 0);

if (pto == NULL)

return NULL;

pto->fn = Py_NewRef(func);

nargs = PyTuple_GetSlice(args, 1, PY_SSIZE_T_MAX);

if (nargs == NULL) {

Py_DECREF(pto);

return NULL;

}

if (pargs == NULL) {

pto->args = nargs;

}

else {

pto->args = PySequence_Concat(pargs, nargs);

Py_DECREF(nargs);

if (pto->args == NULL) {

Py_DECREF(pto);

return NULL;

}

assert(PyTuple_Check(pto->args));

}

if (pkw == NULL || PyDict_GET_SIZE(pkw) == 0) {

if (kw == NULL) {

pto->kw = PyDict_New();

}

else if (Py_REFCNT(kw) == 1) {

pto->kw = Py_NewRef(kw);

}

else {

pto->kw = PyDict_Copy(kw);

}

}

else {

pto->kw = PyDict_Copy(pkw);

if (kw != NULL && pto->kw != NULL) {

if (PyDict_Merge(pto->kw, kw, 1) != 0) {

Py_DECREF(pto);

return NULL;

}

}

}

if (pto->kw == NULL) {

Py_DECREF(pto);

return NULL;

}

partial_setvectorcall(pto);

return (PyObject *)pto;

}

static int

partial_clear(partialobject *pto)

{

Py_CLEAR(pto->fn);

Py_CLEAR(pto->args);

Py_CLEAR(pto->kw);

Py_CLEAR(pto->dict);

return 0;

}

static int

partial_traverse(partialobject *pto, visitproc visit, void *arg)

{

Py_VISIT(Py_TYPE(pto));

Py_VISIT(pto->fn);

Py_VISIT(pto->args);

Py_VISIT(pto->kw);

Py_VISIT(pto->dict);

return 0;

}

static void

partial_dealloc(partialobject *pto)

{

PyTypeObject *tp = Py_TYPE(pto);

/* bpo-31095: UnTrack is needed before calling any callbacks */

PyObject_GC_UnTrack(pto);

FT_CLEAR_WEAKREFS((PyObject*)pto, pto->weakreflist);

(void)partial_clear(pto);

tp->tp_free(pto);

Py_DECREF(tp);

}

static PyObject *

partial_descr_get(PyObject *self, PyObject *obj, PyObject *type)

{

if (obj == Py_None || obj == NULL) {

return Py_NewRef(self);

}

if (PyErr_WarnEx(PyExc_FutureWarning,

"functools.partial will be a method descriptor in "

"future Python versions; wrap it in staticmethod() "

"if you want to preserve the old behavior", 1) < 0)

{

return NULL;

}

return Py_NewRef(self);

}

/* Merging keyword arguments using the vectorcall convention is messy, so

* if we would need to do that, we stop using vectorcall and fall back

* to using partial_call() instead. */

Py_NO_INLINE static PyObject *

partial_vectorcall_fallback(PyThreadState *tstate, partialobject *pto,

PyObject *const *args, size_t nargsf,

PyObject *kwnames)

{

#ifndef Py_GIL_DISABLED

pto->vectorcall = NULL;

#endif

Py_ssize_t nargs = PyVectorcall_NARGS(nargsf);

return _PyObject_MakeTpCall(tstate, (PyObject *)pto,

args, nargs, kwnames);

}

static PyObject *

partial_vectorcall(partialobject *pto, PyObject *const *args,

size_t nargsf, PyObject *kwnames)

{

PyThreadState *tstate = _PyThreadState_GET();

/* pto->kw is mutable, so need to check every time */

if (PyDict_GET_SIZE(pto->kw)) {

return partial_vectorcall_fallback(tstate, pto, args, nargsf, kwnames);

}

Py_ssize_t nargs = PyVectorcall_NARGS(nargsf);

Py_ssize_t nargs_total = nargs;

if (kwnames != NULL) {

nargs_total += PyTuple_GET_SIZE(kwnames);

}

PyObject **pto_args = _PyTuple_ITEMS(pto->args);

Py_ssize_t pto_nargs = PyTuple_GET_SIZE(pto->args);

/* Fast path if we're called without arguments */

if (nargs_total == 0) {

return _PyObject_VectorcallTstate(tstate, pto->fn,

pto_args, pto_nargs, NULL);

}

/* Fast path using PY_VECTORCALL_ARGUMENTS_OFFSET to prepend a single

* positional argument */

if (pto_nargs == 1 && (nargsf & PY_VECTORCALL_ARGUMENTS_OFFSET)) {

PyObject **newargs = (PyObject **)args - 1;

PyObject *tmp = newargs[0];

newargs[0] = pto_args[0];

PyObject *ret = _PyObject_VectorcallTstate(tstate, pto->fn,

newargs, nargs + 1, kwnames);

newargs[0] = tmp;

return ret;

}

Py_ssize_t newnargs_total = pto_nargs + nargs_total;

PyObject *small_stack[_PY_FASTCALL_SMALL_STACK];

PyObject *ret;

PyObject **stack;

if (newnargs_total <= (Py_ssize_t)Py_ARRAY_LENGTH(small_stack)) {

stack = small_stack;

}

else {

stack = PyMem_Malloc(newnargs_total * sizeof(PyObject *));

if (stack == NULL) {

PyErr_NoMemory();

return NULL;

}

}

/* Copy to new stack, using borrowed references */

memcpy(stack, pto_args, pto_nargs * sizeof(PyObject*));

memcpy(stack + pto_nargs, args, nargs_total * sizeof(PyObject*));

ret = _PyObject_VectorcallTstate(tstate, pto->fn,

stack, pto_nargs + nargs, kwnames);

if (stack != small_stack) {

PyMem_Free(stack);

}

return ret;

}

/* Set pto->vectorcall depending on the parameters of the partial object */

static void

partial_setvectorcall(partialobject *pto)

{

if (PyVectorcall_Function(pto->fn) == NULL) {

/* Don't use vectorcall if the underlying function doesn't support it */

pto->vectorcall = NULL;

}

/* We could have a special case if there are no arguments,

* but that is unlikely (why use partial without arguments?),

* so we don't optimize that */

else {

pto->vectorcall = (vectorcallfunc)partial_vectorcall;

}

}

// Not converted to argument clinic, because of `*args, **kwargs` arguments.

static PyObject *

partial_call(partialobject *pto, PyObject *args, PyObject *kwargs)

{

assert(PyCallable_Check(pto->fn));

assert(PyTuple_Check(pto->args));

assert(PyDict_Check(pto->kw));

/* Merge keywords */

PyObject *kwargs2;

if (PyDict_GET_SIZE(pto->kw) == 0) {

/* kwargs can be NULL */

kwargs2 = Py_XNewRef(kwargs);

}

else {

/* bpo-27840, bpo-29318: dictionary of keyword parameters must be

copied, because a function using "**kwargs" can modify the

dictionary. */

kwargs2 = PyDict_Copy(pto->kw);

if (kwargs2 == NULL) {

return NULL;

}

if (kwargs != NULL) {

if (PyDict_Merge(kwargs2, kwargs, 1) != 0) {

Py_DECREF(kwargs2);

return NULL;

}

}

}

/* Merge positional arguments */

/* Note: tupleconcat() is optimized for empty tuples */

PyObject *args2 = PySequence_Concat(pto->args, args);

if (args2 == NULL) {

Py_XDECREF(kwargs2);

return NULL;

}

PyObject *res = PyObject_Call(pto->fn, args2, kwargs2);

Py_DECREF(args2);

Py_XDECREF(kwargs2);

return res;

}

PyDoc_STRVAR(partial_doc,

"partial(func, /, *args, **keywords)\n--\n\n\

Create a new function with partial application of the given arguments\n\

and keywords.");

#define OFF(x) offsetof(partialobject, x)

static PyMemberDef partial_memberlist[] = {

{"func", _Py_T_OBJECT, OFF(fn), Py_READONLY,

"function object to use in future partial calls"},

{"args", _Py_T_OBJECT, OFF(args), Py_READONLY,

"tuple of arguments to future partial calls"},

{"keywords", _Py_T_OBJECT, OFF(kw), Py_READONLY,

"dictionary of keyword arguments to future partial calls"},

{"__weaklistoffset__", Py_T_PYSSIZET,

offsetof(partialobject, weakreflist), Py_READONLY},

{"__dictoffset__", Py_T_PYSSIZET,

offsetof(partialobject, dict), Py_READONLY},

{"__vectorcalloffset__", Py_T_PYSSIZET,

offsetof(partialobject, vectorcall), Py_READONLY},

{NULL} /* Sentinel */

};

static PyGetSetDef partial_getsetlist[] = {

{"__dict__", PyObject_GenericGetDict, PyObject_GenericSetDict},

{NULL} /* Sentinel */

};

static PyObject *

partial_repr(partialobject *pto)

{

PyObject *result = NULL;

PyObject *arglist = NULL;

PyObject *mod = NULL;

PyObject *name = NULL;

Py_ssize_t i, n;

PyObject *key, *value;

int status;

status = Py_ReprEnter((PyObject *)pto);

if (status != 0) {

if (status < 0) {

return NULL;

}

return PyUnicode_FromString("...");

}

/* Reference arguments in case they change */

PyObject *fn = Py_NewRef(pto->fn);

PyObject *args = Py_NewRef(pto->args);

PyObject *kw = Py_NewRef(pto->kw);

assert(PyTuple_Check(args));

assert(PyDict_Check(kw));

arglist = PyUnicode_FromString("");

if (arglist == NULL) {

goto done;

}

/* Pack positional arguments */

n = PyTuple_GET_SIZE(args);

for (i = 0; i < n; i++) {

Py_SETREF(arglist, PyUnicode_FromFormat("%U, %R", arglist,

PyTuple_GET_ITEM(args, i)));

if (arglist == NULL) {

goto done;

}

}

/* Pack keyword arguments */

for (i = 0; PyDict_Next(kw, &i, &key, &value);) {

/* Prevent key.__str__ from deleting the value. */

Py_INCREF(value);

Py_SETREF(arglist, PyUnicode_FromFormat("%U, %S=%R", arglist,

key, value));

Py_DECREF(value);

if (arglist == NULL) {

goto done;

}

}

mod = PyType_GetModuleName(Py_TYPE(pto));

if (mod == NULL) {

goto done;

}

name = PyType_GetQualName(Py_TYPE(pto));

if (name == NULL) {

goto done;

}

result = PyUnicode_FromFormat("%S.%S(%R%U)", mod, name, fn, arglist);

done:

Py_XDECREF(name);

Py_XDECREF(mod);

Py_XDECREF(arglist);

Py_DECREF(fn);

Py_DECREF(args);

Py_DECREF(kw);

Py_ReprLeave((PyObject *)pto);

return result;

}

/* Pickle strategy:

__reduce__ by itself doesn't support getting kwargs in the unpickle

operation so we define a __setstate__ that replaces all the information

about the partial. If we only replaced part of it someone would use

it as a hook to do strange things.

*/

static PyObject *

partial_reduce(partialobject *pto, PyObject *unused)

{

return Py_BuildValue("O(O)(OOOO)", Py_TYPE(pto), pto->fn, pto->fn,

pto->args, pto->kw,

pto->dict ? pto->dict : Py_None);

}

static PyObject *

partial_setstate(partialobject *pto, PyObject *state)

{

PyObject *fn, *fnargs, *kw, *dict;

if (!PyTuple_Check(state) ||

!PyArg_ParseTuple(state, "OOOO", &fn, &fnargs, &kw, &dict) ||

!PyCallable_Check(fn) ||

!PyTuple_Check(fnargs) ||

(kw != Py_None && !PyDict_Check(kw)) ||

(dict != Py_None && !PyDict_Check(dict)))

{

PyErr_SetString(PyExc_TypeError, "invalid partial state");

return NULL;

}

if(!PyTuple_CheckExact(fnargs))

fnargs = PySequence_Tuple(fnargs);

else

Py_INCREF(fnargs);

if (fnargs == NULL)

return NULL;

if (kw == Py_None)

kw = PyDict_New();

else if(!PyDict_CheckExact(kw))

kw = PyDict_Copy(kw);

else

Py_INCREF(kw);

if (kw == NULL) {

Py_DECREF(fnargs);

return NULL;

}

if (dict == Py_None)

dict = NULL;

else

Py_INCREF(dict);

Py_SETREF(pto->fn, Py_NewRef(fn));

Py_SETREF(pto->args, fnargs);

Py_SETREF(pto->kw, kw);

Py_XSETREF(pto->dict, dict);

partial_setvectorcall(pto);

Py_RETURN_NONE;

}

static PyMethodDef partial_methods[] = {

{"__reduce__", (PyCFunction)partial_reduce, METH_NOARGS},

{"__setstate__", (PyCFunction)partial_setstate, METH_O},

{"__class_getitem__", Py_GenericAlias,

METH_O|METH_CLASS,

PyDoc_STR("partial is generic over the wrapped function's return type")},

{NULL, NULL} /* sentinel */

};

static PyType_Slot partial_type_slots[] = {

{Py_tp_dealloc, partial_dealloc},

{Py_tp_repr, partial_repr},

{Py_tp_call, partial_call},

{Py_tp_getattro, PyObject_GenericGetAttr},

{Py_tp_setattro, PyObject_GenericSetAttr},

{Py_tp_doc, (void *)partial_doc},

{Py_tp_traverse, partial_traverse},

{Py_tp_clear, partial_clear},

{Py_tp_methods, partial_methods},

{Py_tp_members, partial_memberlist},

{Py_tp_getset, partial_getsetlist},

{Py_tp_descr_get, (descrgetfunc)partial_descr_get},

{Py_tp_new, partial_new},

{Py_tp_free, PyObject_GC_Del},

{0, 0}

};

static PyType_Spec partial_type_spec = {

.name = "functools.partial",

.basicsize = sizeof(partialobject),

.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |

Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_VECTORCALL |

Py_TPFLAGS_IMMUTABLETYPE,

.slots = partial_type_slots

};

/* cmp_to_key ***************************************************************/

typedef struct {

PyObject_HEAD

PyObject *cmp;

PyObject *object;

} keyobject;

static int

keyobject_clear(keyobject *ko)

{

Py_CLEAR(ko->cmp);

Py_CLEAR(ko->object);

return 0;

}

static void

keyobject_dealloc(keyobject *ko)

{

PyTypeObject *tp = Py_TYPE(ko);

PyObject_GC_UnTrack(ko);

(void)keyobject_clear(ko);

tp->tp_free(ko);

Py_DECREF(tp);

}

static int

keyobject_traverse(keyobject *ko, visitproc visit, void *arg)

{

Py_VISIT(Py_TYPE(ko));

Py_VISIT(ko->cmp);

Py_VISIT(ko->object);

return 0;

}

static PyMemberDef keyobject_members[] = {

{"obj", _Py_T_OBJECT,

offsetof(keyobject, object), 0,

PyDoc_STR("Value wrapped by a key function.")},

{NULL}

};

static PyObject *

keyobject_text_signature(PyObject *self, void *Py_UNUSED(ignored))

{

return PyUnicode_FromString("(obj)");

}

static PyGetSetDef keyobject_getset[] = {

{"__text_signature__", keyobject_text_signature, (setter)NULL},

{NULL}

};

static PyObject *

keyobject_call(keyobject *ko, PyObject *args, PyObject *kwds);

static PyObject *

keyobject_richcompare(PyObject *ko, PyObject *other, int op);

static PyType_Slot keyobject_type_slots[] = {

{Py_tp_dealloc, keyobject_dealloc},

{Py_tp_call, keyobject_call},

{Py_tp_getattro, PyObject_GenericGetAttr},

{Py_tp_traverse, keyobject_traverse},

{Py_tp_clear, keyobject_clear},

{Py_tp_richcompare, keyobject_richcompare},

{Py_tp_members, keyobject_members},

{Py_tp_getset, keyobject_getset},

{0, 0}

};

static PyType_Spec keyobject_type_spec = {

.name = "functools.KeyWrapper",

.basicsize = sizeof(keyobject),

.flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_DISALLOW_INSTANTIATION |

Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_IMMUTABLETYPE),

.slots = keyobject_type_slots

};

static PyObject *

keyobject_call(keyobject *ko, PyObject *args, PyObject *kwds)

{

PyObject *object;

keyobject *result;

static char *kwargs[] = {"obj", NULL};

if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:K", kwargs, &object))

return NULL;

result = PyObject_GC_New(keyobject, Py_TYPE(ko));

if (result == NULL) {

return NULL;

}

result->cmp = Py_NewRef(ko->cmp);

result->object = Py_NewRef(object);

PyObject_GC_Track(result);

return (PyObject *)result;

}

static PyObject *

keyobject_richcompare(PyObject *ko, PyObject *other, int op)

{

if (!Py_IS_TYPE(other, Py_TYPE(ko))) {

PyErr_Format(PyExc_TypeError, "other argument must be K instance");

return NULL;

}

PyObject *compare = ((keyobject *) ko)->cmp;

assert(compare != NULL);

PyObject *x = ((keyobject *) ko)->object;

PyObject *y = ((keyobject *) other)->object;

if (!x || !y){

PyErr_Format(PyExc_AttributeError, "object");

return NULL;

}

/* Call the user's comparison function and translate the 3-way

* result into true or false (or error).

*/

PyObject* args[2] = {x, y};

PyObject *res = PyObject_Vectorcall(compare, args, 2, NULL);

if (res == NULL) {

return NULL;

}

PyObject *answer = PyObject_RichCompare(res, _PyLong_GetZero(), op);

Py_DECREF(res);

return answer;

}

/*[clinic input]

_functools.cmp_to_key

mycmp: object

Function that compares two objects.

Convert a cmp= function into a key= function.

[clinic start generated code]*/

static PyObject *

_functools_cmp_to_key_impl(PyObject *module, PyObject *mycmp)

/*[clinic end generated code: output=71eaad0f4fc81f33 input=d1b76f231c0dfeb3]*/

{

keyobject *object;

_functools_state *state;

state = get_functools_state(module);

object = PyObject_GC_New(keyobject, state->keyobject_type);

if (!object)

return NULL;

object->cmp = Py_NewRef(mycmp);

object->object = NULL;

PyObject_GC_Track(object);

return (PyObject *)object;

}

/* reduce (used to be a builtin) ********************************************/

// Not converted to argument clinic, because of `args` in-place modification.

// AC will affect performance.

static PyObject *

functools_reduce(PyObject *self, PyObject *args)

{

PyObject *seq, *func, *result = NULL, *it;

if (!PyArg_UnpackTuple(args, "reduce", 2, 3, &func, &seq, &result))

return NULL;

if (result != NULL)

Py_INCREF(result);

it = PyObject_GetIter(seq);

if (it == NULL) {

if (PyErr_ExceptionMatches(PyExc_TypeError))

PyErr_SetString(PyExc_TypeError,

"reduce() arg 2 must support iteration");

Py_XDECREF(result);

return NULL;

}

if ((args = PyTuple_New(2)) == NULL)

goto Fail;

for (;;) {

PyObject *op2;

if (Py_REFCNT(args) > 1) {

Py_DECREF(args);

if ((args = PyTuple_New(2)) == NULL)

goto Fail;

}

op2 = PyIter_Next(it);

if (op2 == NULL) {

if (PyErr_Occurred())

goto Fail;

break;

}

if (result == NULL)

result = op2;

else {

/* Update the args tuple in-place */

assert(Py_REFCNT(args) == 1);

Py_XSETREF(_PyTuple_ITEMS(args)[0], result);

Py_XSETREF(_PyTuple_ITEMS(args)[1], op2);

if ((result = PyObject_Call(func, args, NULL)) == NULL) {

goto Fail;

}

// bpo-42536: The GC may have untracked this args tuple. Since we're

// recycling it, make sure it's tracked again:

if (!_PyObject_GC_IS_TRACKED(args)) {

_PyObject_GC_TRACK(args);

}

}

}

Py_DECREF(args);

if (result == NULL)

PyErr_SetString(PyExc_TypeError,

"reduce() of empty iterable with no initial value");

Py_DECREF(it);

return result;

Fail:

Py_XDECREF(args);

Py_XDECREF(result);

Py_DECREF(it);

return NULL;

}

PyDoc_STRVAR(functools_reduce_doc,

"reduce(function, iterable[, initial], /) -> value\n\

\n\

Apply a function of two arguments cumulatively to the items of an iterable, from left to right.\n\

\n\

This effectively reduces the iterable to a single value. If initial is present,\n\

it is placed before the items of the iterable in the calculation, and serves as\n\

a default when the iterable is empty.\n\

\n\

For example, reduce(lambda x, y: x+y, [1, 2, 3, 4, 5])\n\

calculates ((((1 + 2) + 3) + 4) + 5).");

/* lru_cache object **********************************************************/

/* There are four principal algorithmic differences from the pure python version:

1). The C version relies on the GIL instead of having its own reentrant lock.

2). The prev/next link fields use borrowed references.

3). For a full cache, the pure python version rotates the location of the

root entry so that it never has to move individual links and it can

limit updates to just the key and result fields. However, in the C

version, links are temporarily removed while the cache dict updates are

occurring. Afterwards, they are appended or prepended back into the

doubly-linked lists.

4) In the Python version, the _HashSeq class is used to prevent __hash__

from being called more than once. In the C version, the "known hash"

variants of dictionary calls as used to the same effect.

*/

struct lru_list_elem;

struct lru_cache_object;

typedef struct lru_list_elem {

PyObject_HEAD

struct lru_list_elem *prev, *next; /* borrowed links */

Py_hash_t hash;

PyObject *key, *result;

} lru_list_elem;

static void

lru_list_elem_dealloc(lru_list_elem *link)

{

PyTypeObject *tp = Py_TYPE(link);

Py_XDECREF(link->key);

Py_XDECREF(link->result);

tp->tp_free(link);

Py_DECREF(tp);

}

static PyType_Slot lru_list_elem_type_slots[] = {

{Py_tp_dealloc, lru_list_elem_dealloc},

{0, 0}

};

static PyType_Spec lru_list_elem_type_spec = {

.name = "functools._lru_list_elem",

.basicsize = sizeof(lru_list_elem),

.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_DISALLOW_INSTANTIATION |

Py_TPFLAGS_IMMUTABLETYPE,

.slots = lru_list_elem_type_slots

};

typedef PyObject *(*lru_cache_ternaryfunc)(struct lru_cache_object *, PyObject *, PyObject *);

typedef struct lru_cache_object {

lru_list_elem root; /* includes PyObject_HEAD */

lru_cache_ternaryfunc wrapper;

int typed;

PyObject *cache;

Py_ssize_t hits;

PyObject *func;

Py_ssize_t maxsize;

Py_ssize_t misses;

/* the kwd_mark is used delimit args and keywords in the cache keys */

PyObject *kwd_mark;

PyTypeObject *lru_list_elem_type;

PyObject *cache_info_type;

PyObject *dict;

PyObject *weakreflist;

} lru_cache_object;

static PyObject *

lru_cache_make_key(PyObject *kwd_mark, PyObject *args,

PyObject *kwds, int typed)

{

PyObject *key, *keyword, *value;

Py_ssize_t key_size, pos, key_pos, kwds_size;

kwds_size = kwds ? PyDict_GET_SIZE(kwds) : 0;

/* short path, key will match args anyway, which is a tuple */

if (!typed && !kwds_size) {

if (PyTuple_GET_SIZE(args) == 1) {

key = PyTuple_GET_ITEM(args, 0);

if (PyUnicode_CheckExact(key) || PyLong_CheckExact(key)) {

/* For common scalar keys, save space by

dropping the enclosing args tuple */

return Py_NewRef(key);

}

}

return Py_NewRef(args);

}

key_size = PyTuple_GET_SIZE(args);

if (kwds_size)

key_size += kwds_size * 2 + 1;

if (typed)

key_size += PyTuple_GET_SIZE(args) + kwds_size;

key = PyTuple_New(key_size);

if (key == NULL)

return NULL;

key_pos = 0;

for (pos = 0; pos < PyTuple_GET_SIZE(args); ++pos) {

PyObject *item = PyTuple_GET_ITEM(args, pos);

PyTuple_SET_ITEM(key, key_pos++, Py_NewRef(item));

}

if (kwds_size) {

PyTuple_SET_ITEM(key, key_pos++, Py_NewRef(kwd_mark));

for (pos = 0; PyDict_Next(kwds, &pos, &keyword, &value);) {

PyTuple_SET_ITEM(key, key_pos++, Py_NewRef(keyword));

PyTuple_SET_ITEM(key, key_pos++, Py_NewRef(value));

}

assert(key_pos == PyTuple_GET_SIZE(args) + kwds_size * 2 + 1);

}

if (typed) {

for (pos = 0; pos < PyTuple_GET_SIZE(args); ++pos) {

PyObject *item = (PyObject *)Py_TYPE(PyTuple_GET_ITEM(args, pos));

PyTuple_SET_ITEM(key, key_pos++, Py_NewRef(item));

}

if (kwds_size) {

for (pos = 0; PyDict_Next(kwds, &pos, &keyword, &value);) {

PyObject *item = (PyObject *)Py_TYPE(value);

PyTuple_SET_ITEM(key, key_pos++, Py_NewRef(item));

}

}

}

assert(key_pos == key_size);

return key;

}

static PyObject *

uncached_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds)

{

PyObject *result;

self->misses++;

result = PyObject_Call(self->func, args, kwds);

if (!result)

return NULL;

return result;

}

static PyObject *

infinite_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds)

{

PyObject *result;

Py_hash_t hash;

PyObject *key = lru_cache_make_key(self->kwd_mark, args, kwds, self->typed);

if (!key)

return NULL;

hash = PyObject_Hash(key);

if (hash == -1) {

Py_DECREF(key);

return NULL;

}

result = _PyDict_GetItem_KnownHash(self->cache, key, hash);

if (result) {

Py_INCREF(result);

self->hits++;

Py_DECREF(key);

return result;

}

if (PyErr_Occurred()) {

Py_DECREF(key);

return NULL;

}

self->misses++;

result = PyObject_Call(self->func, args, kwds);

if (!result) {

Py_DECREF(key);

return NULL;

}

if (_PyDict_SetItem_KnownHash(self->cache, key, result, hash) < 0) {

Py_DECREF(result);

Py_DECREF(key);

return NULL;

}

Py_DECREF(key);

return result;

}

static void

lru_cache_extract_link(lru_list_elem *link)

{

lru_list_elem *link_prev = link->prev;

lru_list_elem *link_next = link->next;

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;