#include "Python.h"

#include "pycore_object.h"

#include "pycore_pystate.h"

#include "pycore_tupleobject.h"

#include "frameobject.h"

static PyObject *

cfunction_call_varargs(PyObject *func, PyObject *args, PyObject *kwargs);

static PyObject *const *

_PyStack_UnpackDict(PyObject *const *args, Py_ssize_t nargs, PyObject *kwargs,

PyObject **p_kwnames);

static void

_PyStack_UnpackDict_Free(PyObject *const *stack, Py_ssize_t nargs,

PyObject *kwnames);

static PyObject *

null_error(void)

{

if (!PyErr_Occurred())

PyErr_SetString(PyExc_SystemError,

"null argument to internal routine");

return NULL;

}

PyObject*

_Py_CheckFunctionResult(PyObject *callable, PyObject *result, const char *where)

{

int err_occurred = (PyErr_Occurred() != NULL);

assert((callable != NULL) ^ (where != NULL));

if (result == NULL) {

if (!err_occurred) {

if (callable)

PyErr_Format(PyExc_SystemError,

"%R returned NULL without setting an error",

callable);

else

PyErr_Format(PyExc_SystemError,

"%s returned NULL without setting an error",

where);

#ifdef Py_DEBUG

/* Ensure that the bug is caught in debug mode */

Py_FatalError("a function returned NULL without setting an error");

#endif

return NULL;

}

}

else {

if (err_occurred) {

Py_DECREF(result);

if (callable) {

_PyErr_FormatFromCause(PyExc_SystemError,

"%R returned a result with an error set",

callable);

}

else {

_PyErr_FormatFromCause(PyExc_SystemError,

"%s returned a result with an error set",

where);

}

#ifdef Py_DEBUG

/* Ensure that the bug is caught in debug mode */

Py_FatalError("a function returned a result with an error set");

#endif

return NULL;

}

}

return result;

}

/* --- Core PyObject call functions ------------------------------- */

/* Call a callable Python object without any arguments */

PyObject *

PyObject_CallNoArgs(PyObject *func)

{

return _PyObject_CallNoArg(func);

}

PyObject *

_PyObject_FastCallDict(PyObject *callable, PyObject *const *args,

size_t nargsf, PyObject *kwargs)

{

/* _PyObject_FastCallDict() must not be called with an exception set,

because it can clear it (directly or indirectly) and so the

caller loses its exception */

assert(!PyErr_Occurred());

assert(callable != NULL);

Py_ssize_t nargs = PyVectorcall_NARGS(nargsf);

assert(nargs >= 0);

assert(nargs == 0 || args != NULL);

assert(kwargs == NULL || PyDict_Check(kwargs));

vectorcallfunc func = _PyVectorcall_Function(callable);

if (func == NULL) {

/* Use tp_call instead */

return _PyObject_MakeTpCall(callable, args, nargs, kwargs);

}

PyObject *res;

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

res = func(callable, args, nargsf, NULL);

}

else {

PyObject *kwnames;

PyObject *const *newargs;

newargs = _PyStack_UnpackDict(args, nargs, kwargs, &kwnames);

if (newargs == NULL) {

return NULL;

}

res = func(callable, newargs,

nargs | PY_VECTORCALL_ARGUMENTS_OFFSET, kwnames);

_PyStack_UnpackDict_Free(newargs, nargs, kwnames);

}

return _Py_CheckFunctionResult(callable, res, NULL);

}

PyObject *

_PyObject_MakeTpCall(PyObject *callable, PyObject *const *args, Py_ssize_t nargs, PyObject *keywords)

{

/* Slow path: build a temporary tuple for positional arguments and a

* temporary dictionary for keyword arguments (if any) */

ternaryfunc call = Py_TYPE(callable)->tp_call;

if (call == NULL) {

PyErr_Format(PyExc_TypeError, "'%.200s' object is not callable",

Py_TYPE(callable)->tp_name);

return NULL;

}

assert(nargs >= 0);

assert(nargs == 0 || args != NULL);

assert(keywords == NULL || PyTuple_Check(keywords) || PyDict_Check(keywords));

PyObject *argstuple = _PyTuple_FromArray(args, nargs);

if (argstuple == NULL) {

return NULL;

}

PyObject *kwdict;

if (keywords == NULL || PyDict_Check(keywords)) {

kwdict = keywords;

}

else {

if (PyTuple_GET_SIZE(keywords)) {

assert(args != NULL);

kwdict = _PyStack_AsDict(args + nargs, keywords);

if (kwdict == NULL) {

Py_DECREF(argstuple);

return NULL;

}

}

else {

keywords = kwdict = NULL;

}

}

PyObject *result = NULL;

if (Py_EnterRecursiveCall(" while calling a Python object") == 0)

{

result = call(callable, argstuple, kwdict);

Py_LeaveRecursiveCall();

}

Py_DECREF(argstuple);

if (kwdict != keywords) {

Py_DECREF(kwdict);

}

result = _Py_CheckFunctionResult(callable, result, NULL);

return result;

}

PyObject *

PyVectorcall_Call(PyObject *callable, PyObject *tuple, PyObject *kwargs)

{

/* get vectorcallfunc as in _PyVectorcall_Function, but without

* the _Py_TPFLAGS_HAVE_VECTORCALL check */

Py_ssize_t offset = Py_TYPE(callable)->tp_vectorcall_offset;

if (offset <= 0) {

PyErr_Format(PyExc_TypeError, "'%.200s' object does not support vectorcall",

Py_TYPE(callable)->tp_name);

return NULL;

}

vectorcallfunc func = *(vectorcallfunc *)(((char *)callable) + offset);

if (func == NULL) {

PyErr_Format(PyExc_TypeError, "'%.200s' object does not support vectorcall",

Py_TYPE(callable)->tp_name);

return NULL;

}

Py_ssize_t nargs = PyTuple_GET_SIZE(tuple);

/* Fast path for no keywords */

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

return func(callable, _PyTuple_ITEMS(tuple), nargs, NULL);

}

/* Convert arguments & call */

PyObject *const *args;

PyObject *kwnames;

args = _PyStack_UnpackDict(_PyTuple_ITEMS(tuple), nargs, kwargs, &kwnames);

if (args == NULL) {

return NULL;

}

PyObject *result = func(callable, args,

nargs | PY_VECTORCALL_ARGUMENTS_OFFSET, kwnames);

_PyStack_UnpackDict_Free(args, nargs, kwnames);

return _Py_CheckFunctionResult(callable, result, NULL);

}

PyObject *

PyObject_Call(PyObject *callable, PyObject *args, PyObject *kwargs)

{

ternaryfunc call;

PyObject *result;

/* PyObject_Call() must not be called with an exception set,

because it can clear it (directly or indirectly) and so the

caller loses its exception */

assert(!PyErr_Occurred());

assert(PyTuple_Check(args));

assert(kwargs == NULL || PyDict_Check(kwargs));

if (_PyVectorcall_Function(callable) != NULL) {

return PyVectorcall_Call(callable, args, kwargs);

}

else if (PyCFunction_Check(callable)) {

/* This must be a METH_VARARGS function, otherwise we would be

* in the previous case */

return cfunction_call_varargs(callable, args, kwargs);

}

else {

call = callable->ob_type->tp_call;

if (call == NULL) {

PyErr_Format(PyExc_TypeError, "'%.200s' object is not callable",

callable->ob_type->tp_name);

return NULL;

}

if (Py_EnterRecursiveCall(" while calling a Python object"))

return NULL;

result = (*call)(callable, args, kwargs);

Py_LeaveRecursiveCall();

return _Py_CheckFunctionResult(callable, result, NULL);

}

}

/* --- PyFunction call functions ---------------------------------- */

static PyObject* _Py_HOT_FUNCTION

function_code_fastcall(PyCodeObject *co, PyObject *const *args, Py_ssize_t nargs,

PyObject *globals)

{

PyFrameObject *f;

PyThreadState *tstate = _PyThreadState_GET();

PyObject **fastlocals;

Py_ssize_t i;

PyObject *result;

assert(globals != NULL);

/* XXX Perhaps we should create a specialized

_PyFrame_New_NoTrack() that doesn't take locals, but does

take builtins without sanity checking them.

*/

assert(tstate != NULL);

f = _PyFrame_New_NoTrack(tstate, co, globals, NULL);

if (f == NULL) {

return NULL;

}

fastlocals = f->f_localsplus;

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

Py_INCREF(*args);

fastlocals[i] = *args++;

}

result = PyEval_EvalFrameEx(f,0);

if (Py_REFCNT(f) > 1) {

Py_DECREF(f);

_PyObject_GC_TRACK(f);

}

else {

++tstate->recursion_depth;

Py_DECREF(f);

--tstate->recursion_depth;

}

return result;

}

PyObject *

_PyFunction_Vectorcall(PyObject *func, PyObject* const* stack,

size_t nargsf, PyObject *kwnames)

{

PyCodeObject *co = (PyCodeObject *)PyFunction_GET_CODE(func);

PyObject *globals = PyFunction_GET_GLOBALS(func);

PyObject *argdefs = PyFunction_GET_DEFAULTS(func);

PyObject *kwdefs, *closure, *name, *qualname;

PyObject **d;

Py_ssize_t nkwargs = (kwnames == NULL) ? 0 : PyTuple_GET_SIZE(kwnames);

Py_ssize_t nd;

assert(PyFunction_Check(func));

Py_ssize_t nargs = PyVectorcall_NARGS(nargsf);

assert(nargs >= 0);

assert(kwnames == NULL || PyTuple_CheckExact(kwnames));

assert((nargs == 0 && nkwargs == 0) || stack != NULL);

/* kwnames must only contains str strings, no subclass, and all keys must

be unique */

if (co->co_kwonlyargcount == 0 && nkwargs == 0 &&

(co->co_flags & ~PyCF_MASK) == (CO_OPTIMIZED | CO_NEWLOCALS | CO_NOFREE))

{

if (argdefs == NULL && co->co_argcount == nargs) {

return function_code_fastcall(co, stack, nargs, globals);

}

else if (nargs == 0 && argdefs != NULL

&& co->co_argcount == PyTuple_GET_SIZE(argdefs)) {

/* function called with no arguments, but all parameters have

a default value: use default values as arguments .*/

stack = _PyTuple_ITEMS(argdefs);

return function_code_fastcall(co, stack, PyTuple_GET_SIZE(argdefs),

globals);

}

}

kwdefs = PyFunction_GET_KW_DEFAULTS(func);

closure = PyFunction_GET_CLOSURE(func);

name = ((PyFunctionObject *)func) -> func_name;

qualname = ((PyFunctionObject *)func) -> func_qualname;

if (argdefs != NULL) {

d = _PyTuple_ITEMS(argdefs);

nd = PyTuple_GET_SIZE(argdefs);

}

else {

d = NULL;

nd = 0;

}

return _PyEval_EvalCodeWithName((PyObject*)co, globals, (PyObject *)NULL,

stack, nargs,

nkwargs ? _PyTuple_ITEMS(kwnames) : NULL,

stack + nargs,

nkwargs, 1,

d, (int)nd, kwdefs,

closure, name, qualname);

}

/* --- PyCFunction call functions --------------------------------- */

static PyObject *

cfunction_call_varargs(PyObject *func, PyObject *args, PyObject *kwargs)

{

assert(!PyErr_Occurred());

assert(kwargs == NULL || PyDict_Check(kwargs));

PyCFunction meth = PyCFunction_GET_FUNCTION(func);

PyObject *self = PyCFunction_GET_SELF(func);

PyObject *result;

assert(PyCFunction_GET_FLAGS(func) & METH_VARARGS);

if (PyCFunction_GET_FLAGS(func) & METH_KEYWORDS) {

if (Py_EnterRecursiveCall(" while calling a Python object")) {

return NULL;

}

result = (*(PyCFunctionWithKeywords)(void(*)(void))meth)(self, args, kwargs);

Py_LeaveRecursiveCall();

}

else {

if (kwargs != NULL && PyDict_GET_SIZE(kwargs) != 0) {

PyErr_Format(PyExc_TypeError, "%.200s() takes no keyword arguments",

((PyCFunctionObject*)func)->m_ml->ml_name);

return NULL;

}

if (Py_EnterRecursiveCall(" while calling a Python object")) {

return NULL;

}

result = (*meth)(self, args);

Py_LeaveRecursiveCall();

}

return _Py_CheckFunctionResult(func, result, NULL);

}

PyObject *

PyCFunction_Call(PyObject *func, PyObject *args, PyObject *kwargs)

{

/* For METH_VARARGS, we cannot use vectorcall as the vectorcall pointer

* is NULL. This is intentional, since vectorcall would be slower. */

if (PyCFunction_GET_FLAGS(func) & METH_VARARGS) {

return cfunction_call_varargs(func, args, kwargs);

}

return PyVectorcall_Call(func, args, kwargs);

}

/* --- More complex call functions -------------------------------- */

/* External interface to call any callable object.

The args must be a tuple or NULL. The kwargs must be a dict or NULL. */

PyObject *

PyEval_CallObjectWithKeywords(PyObject *callable,

PyObject *args, PyObject *kwargs)

{

#ifdef Py_DEBUG

/* PyEval_CallObjectWithKeywords() must not be called with an exception

set. It raises a new exception if parameters are invalid or if

PyTuple_New() fails, and so the original exception is lost. */

assert(!PyErr_Occurred());

#endif

if (args != NULL && !PyTuple_Check(args)) {

PyErr_SetString(PyExc_TypeError,

"argument list must be a tuple");

return NULL;

}

if (kwargs != NULL && !PyDict_Check(kwargs)) {

PyErr_SetString(PyExc_TypeError,

"keyword list must be a dictionary");

return NULL;

}

if (args == NULL) {

return _PyObject_FastCallDict(callable, NULL, 0, kwargs);

}

else {

return PyObject_Call(callable, args, kwargs);

}

}

PyObject *

PyObject_CallObject(PyObject *callable, PyObject *args)

{

return PyEval_CallObjectWithKeywords(callable, args, NULL);

}

/* Call callable(obj, *args, **kwargs). */

PyObject *

_PyObject_Call_Prepend(PyObject *callable,

PyObject *obj, PyObject *args, PyObject *kwargs)

{

PyObject *small_stack[_PY_FASTCALL_SMALL_STACK];

PyObject **stack;

Py_ssize_t argcount;

PyObject *result;

assert(PyTuple_Check(args));

argcount = PyTuple_GET_SIZE(args);

if (argcount + 1 <= (Py_ssize_t)Py_ARRAY_LENGTH(small_stack)) {

stack = small_stack;

}

else {

stack = PyMem_Malloc((argcount + 1) * sizeof(PyObject *));

if (stack == NULL) {

PyErr_NoMemory();

return NULL;

}

}

/* use borrowed references */

stack[0] = obj;

memcpy(&stack[1],

_PyTuple_ITEMS(args),

argcount * sizeof(PyObject *));

result = _PyObject_FastCallDict(callable,

stack, argcount + 1,

kwargs);

if (stack != small_stack) {

PyMem_Free(stack);

}

return result;

}

/* --- Call with a format string ---------------------------------- */

static PyObject *

_PyObject_CallFunctionVa(PyObject *callable, const char *format,

va_list va, int is_size_t)

{

PyObject* small_stack[_PY_FASTCALL_SMALL_STACK];

const Py_ssize_t small_stack_len = Py_ARRAY_LENGTH(small_stack);

PyObject **stack;

Py_ssize_t nargs, i;

PyObject *result;

if (callable == NULL) {

return null_error();

}

if (!format || !*format) {

return _PyObject_CallNoArg(callable);

}

if (is_size_t) {

stack = _Py_VaBuildStack_SizeT(small_stack, small_stack_len,

format, va, &nargs);

}

else {

stack = _Py_VaBuildStack(small_stack, small_stack_len,

format, va, &nargs);

}

if (stack == NULL) {

return NULL;

}

if (nargs == 1 && PyTuple_Check(stack[0])) {

/* Special cases for backward compatibility:

- PyObject_CallFunction(func, "O", tuple) calls func(*tuple)

- PyObject_CallFunction(func, "(OOO)", arg1, arg2, arg3) calls

func(*(arg1, arg2, arg3)): func(arg1, arg2, arg3) */

PyObject *args = stack[0];

result = _PyObject_FastCall(callable,

_PyTuple_ITEMS(args),

PyTuple_GET_SIZE(args));

}

else {

result = _PyObject_FastCall(callable, stack, nargs);

}

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

Py_DECREF(stack[i]);

}

if (stack != small_stack) {

PyMem_Free(stack);

}

return result;

}

PyObject *

PyObject_CallFunction(PyObject *callable, const char *format, ...)

{

va_list va;

PyObject *result;

va_start(va, format);

result = _PyObject_CallFunctionVa(callable, format, va, 0);

va_end(va);

return result;

}

/* PyEval_CallFunction is exact copy of PyObject_CallFunction.

* This function is kept for backward compatibility.

*/

PyObject *

PyEval_CallFunction(PyObject *callable, const char *format, ...)

{

va_list va;

PyObject *result;

va_start(va, format);

result = _PyObject_CallFunctionVa(callable, format, va, 0);

va_end(va);

return result;

}

PyObject *

_PyObject_CallFunction_SizeT(PyObject *callable, const char *format, ...)

{

va_list va;

PyObject *result;

va_start(va, format);

result = _PyObject_CallFunctionVa(callable, format, va, 1);

va_end(va);

return result;

}

static PyObject*

callmethod(PyObject* callable, const char *format, va_list va, int is_size_t)

{

assert(callable != NULL);

if (!PyCallable_Check(callable)) {

PyErr_Format(PyExc_TypeError,

"attribute of type '%.200s' is not callable",

Py_TYPE(callable)->tp_name);

return NULL;

}

return _PyObject_CallFunctionVa(callable, format, va, is_size_t);

}

PyObject *

PyObject_CallMethod(PyObject *obj, const char *name, const char *format, ...)

{

va_list va;

PyObject *callable, *retval;

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

return null_error();

}

callable = PyObject_GetAttrString(obj, name);

if (callable == NULL)

return NULL;

va_start(va, format);

retval = callmethod(callable, format, va, 0);

va_end(va);

Py_DECREF(callable);

return retval;

}

/* PyEval_CallMethod is exact copy of PyObject_CallMethod.

* This function is kept for backward compatibility.

*/

PyObject *

PyEval_CallMethod(PyObject *obj, const char *name, const char *format, ...)

{

va_list va;

PyObject *callable, *retval;

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

return null_error();

}

callable = PyObject_GetAttrString(obj, name);

if (callable == NULL)

return NULL;

va_start(va, format);

retval = callmethod(callable, format, va, 0);

va_end(va);

Py_DECREF(callable);

return retval;

}

PyObject *

_PyObject_CallMethodId(PyObject *obj, _Py_Identifier *name,

const char *format, ...)

{

va_list va;

PyObject *callable, *retval;

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

return null_error();

}

callable = _PyObject_GetAttrId(obj, name);

if (callable == NULL)

return NULL;

va_start(va, format);

retval = callmethod(callable, format, va, 0);

va_end(va);

Py_DECREF(callable);

return retval;

}

PyObject *

_PyObject_CallMethod_SizeT(PyObject *obj, const char *name,

const char *format, ...)

{

va_list va;

PyObject *callable, *retval;

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

return null_error();

}

callable = PyObject_GetAttrString(obj, name);

if (callable == NULL)

return NULL;

va_start(va, format);

retval = callmethod(callable, format, va, 1);

va_end(va);

Py_DECREF(callable);

return retval;

}

PyObject *

_PyObject_CallMethodId_SizeT(PyObject *obj, _Py_Identifier *name,

const char *format, ...)

{

va_list va;

PyObject *callable, *retval;

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

return null_error();

}

callable = _PyObject_GetAttrId(obj, name);

if (callable == NULL) {

return NULL;

}

va_start(va, format);

retval = callmethod(callable, format, va, 1);

va_end(va);

Py_DECREF(callable);

return retval;

}

/* --- Call with "..." arguments ---------------------------------- */

static PyObject *

object_vacall(PyObject *base, PyObject *callable, va_list vargs)

{

PyObject *small_stack[_PY_FASTCALL_SMALL_STACK];

PyObject **stack;

Py_ssize_t nargs;

PyObject *result;

Py_ssize_t i;

va_list countva;

if (callable == NULL) {

return null_error();

}

/* Count the number of arguments */

va_copy(countva, vargs);

nargs = base ? 1 : 0;

while (1) {

PyObject *arg = va_arg(countva, PyObject *);

if (arg == NULL) {

break;

}

nargs++;

}

va_end(countva);

/* Copy arguments */

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

stack = small_stack;

}

else {

stack = PyMem_Malloc(nargs * sizeof(stack[0]));

if (stack == NULL) {

PyErr_NoMemory();

return NULL;

}

}

i = 0;

if (base) {

stack[i++] = base;

}

for (; i < nargs; ++i) {

stack[i] = va_arg(vargs, PyObject *);

}

/* Call the function */

result = _PyObject_FastCall(callable, stack, nargs);

if (stack != small_stack) {

PyMem_Free(stack);

}

return result;

}

PyObject *

_PyObject_VectorcallMethod(PyObject *name, PyObject *const *args,

size_t nargsf, PyObject *kwnames)

{

assert(name != NULL);

assert(args != NULL);

assert(PyVectorcall_NARGS(nargsf) >= 1);

PyObject *callable = NULL;

/* Use args[0] as "self" argument */

int unbound = _PyObject_GetMethod(args[0], name, &callable);

if (callable == NULL) {

return NULL;

}

if (unbound) {

/* We must remove PY_VECTORCALL_ARGUMENTS_OFFSET since

* that would be interpreted as allowing to change args[-1] */

nargsf &= ~PY_VECTORCALL_ARGUMENTS_OFFSET;

}

else {

/* Skip "self". We can keep PY_VECTORCALL_ARGUMENTS_OFFSET since

* args[-1] in the onward call is args[0] here. */

args++;

nargsf--;

}

PyObject *result = _PyObject_Vectorcall(callable, args, nargsf, kwnames);

Py_DECREF(callable);

return result;

}

PyObject *

PyObject_CallMethodObjArgs(PyObject *obj, PyObject *name, ...)

{

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

return null_error();

}

PyObject *callable = NULL;

int is_method = _PyObject_GetMethod(obj, name, &callable);

if (callable == NULL) {

return NULL;

}

obj = is_method ? obj : NULL;

va_list vargs;

va_start(vargs, name);

PyObject *result = object_vacall(obj, callable, vargs);

va_end(vargs);

Py_DECREF(callable);

return result;

}

PyObject *

_PyObject_CallMethodIdObjArgs(PyObject *obj,

struct _Py_Identifier *name, ...)

{

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

return null_error();

}

PyObject *oname = _PyUnicode_FromId(name); /* borrowed */

if (!oname) {

return NULL;

}

PyObject *callable = NULL;

int is_method = _PyObject_GetMethod(obj, oname, &callable);

if (callable == NULL) {

return NULL;

}

obj = is_method ? obj : NULL;

va_list vargs;

va_start(vargs, name);

PyObject *result = object_vacall(obj, callable, vargs);

va_end(vargs);

Py_DECREF(callable);

return result;

}

PyObject *

PyObject_CallFunctionObjArgs(PyObject *callable, ...)

{

va_list vargs;

PyObject *result;

va_start(vargs, callable);

result = object_vacall(NULL, callable, vargs);

va_end(vargs);

return result;

}

/* --- PyStack functions ------------------------------------------ */

PyObject *

_PyStack_AsDict(PyObject *const *values, PyObject *kwnames)

{

Py_ssize_t nkwargs;

PyObject *kwdict;

Py_ssize_t i;

assert(kwnames != NULL);

nkwargs = PyTuple_GET_SIZE(kwnames);

kwdict = _PyDict_NewPresized(nkwargs);

if (kwdict == NULL) {

return NULL;

}

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

PyObject *key = PyTuple_GET_ITEM(kwnames, i);

PyObject *value = *values++;

/* If key already exists, replace it with the new value */

if (PyDict_SetItem(kwdict, key, value)) {

Py_DECREF(kwdict);

return NULL;

}

}

return kwdict;

}

/* Convert (args, nargs, kwargs: dict) into a (stack, nargs, kwnames: tuple).

Allocate a new argument vector and keyword names tuple. Return the argument

vector; return NULL with exception set on error. Return the keyword names

tuple in *p_kwnames.

The newly allocated argument vector supports PY_VECTORCALL_ARGUMENTS_OFFSET.

When done, you must call _PyStack_UnpackDict_Free(stack, nargs, kwnames)

The type of keyword keys is not checked, these checks should be done

later (ex: _PyArg_ParseStackAndKeywords). */

static PyObject *const *

_PyStack_UnpackDict(PyObject *const *args, Py_ssize_t nargs, PyObject *kwargs,

PyObject **p_kwnames)

{

assert(nargs >= 0);

assert(kwargs != NULL);

assert(PyDict_Check(kwargs));

Py_ssize_t nkwargs = PyDict_GET_SIZE(kwargs);

/* Check for overflow in the PyMem_Malloc() call below. The subtraction

* in this check cannot overflow: both maxnargs and nkwargs are

* non-negative signed integers, so their difference fits in the type. */

Py_ssize_t maxnargs = PY_SSIZE_T_MAX / sizeof(args[0]) - 1;

if (nargs > maxnargs - nkwargs) {

PyErr_NoMemory();

return NULL;

}

/* Add 1 to support PY_VECTORCALL_ARGUMENTS_OFFSET */

PyObject **stack = PyMem_Malloc((1 + nargs + nkwargs) * sizeof(args[0]));

if (stack == NULL) {

PyErr_NoMemory();

return NULL;

}

PyObject *kwnames = PyTuple_New(nkwargs);

if (kwnames == NULL) {

PyMem_Free(stack);

return NULL;

}

stack++; /* For PY_VECTORCALL_ARGUMENTS_OFFSET */

/* Copy positional arguments */

for (Py_ssize_t i = 0; i < nargs; i++) {

Py_INCREF(args[i]);

stack[i] = args[i];

}

PyObject **kwstack = stack + nargs;

/* This loop doesn't support lookup function mutating the dictionary

to change its size. It's a deliberate choice for speed, this function is

called in the performance critical hot code. */

Py_ssize_t pos = 0, i = 0;

PyObject *key, *value;

while (PyDict_Next(kwargs, &pos, &key, &value)) {

Py_INCREF(key);

Py_INCREF(value);

PyTuple_SET_ITEM(kwnames, i, key);

kwstack[i] = value;

i++;

}

*p_kwnames = kwnames;

return stack;

}

static void